PENETRATING

NECK

TISAUMA

INBRIEF Penetrating neck trauma involves a small fraction of a surgeon’s overall clinical experience. However, the extent of potential injuty and the inherent morbidit-y and mortality is not inconsequential. This monograph will discuss the current controversies in the diagnosis and management of the spectrum of injuries involving the cervical region. Historically, care of patients with penetrating neck injuries has been slow to advance. Not until recently, towards the end of World War II, has more than simple ligation of the injured carotid artery been attempted. Primary repair of these injuries, along with improvement in perioperative care, has resulted in progressively more acceptable results. Current controversies, however, revolve around mandatory exploration versus selective observation of these injuries. Advocates of the former approach contend exploration, which has time-proven success, to be a basic principle of trauma care. Surgeons who follow a selective approach question the validity of comparing therapeutic guidelines used previously to treat high-energv, destructive trauma typical of military wounds, with current civilian injuries. Proponents of each provide supportive evidence from both a medical and economical viewpoint. To further complicate the issue, data from recent nonoperative experiences in patients with “minimal” peripheral vascular injuries are being extrapolated to those with cervical vascular trauma. The anatomical infrastructure of the neck contains many lifesustaining and other important elements which are closely positioned in a limited area. A detailed awareness of the cervical region is critical in determining the structures at risk for damage in a given zone of injury. Zone I, the thoracic outlet, extends from the base of the neck to the cricoid cartilage. Zone II encompasses the area between the cricoid cartilage and the angle of the mandible. Injuries in this area are common and easy to access. Moreover, they are associated with a lower mortality rate than Zone I injuries. Finally, Zone III injuries extend from the angle of the mandible to the base of the skull. Injuries in this area are often difficult to approach. EXpOSure of Curr

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the vertebral artery is aided by an extensive knowledge of the network of fascial planes present in the neck, the unique course of the vessel, and the venous plexus which is precariously adjacent to the distal segment of the artery. The anatomic relationships in the neck are of added importance when considering the mechanism of injury. Penetrating neck injury, primarily caused by stab and gunshot wounds, may result in death or disability by affecting the vascular structures of the neck. Exsanguination, cerebral vascular occlusion, or embolization, and neurologic devastation because of spinal cord injury are products of this form of trauma. An injury caused by a projectile necessitates more caution than that caused by a stab wound. The property of the missile may contribute substantially to the extent of destruction, which is related to the cavitation effect. Moreover, missiles have the potential for embolization and have been indicted as contributing to venous air emboli following fatal head and neck wounds. Therefore, not only do bullets have the potential to penetrate deeper than stab wounds, but they may also cause damage extending beyond the boundaries of the missile tract itself. The actual care of patients with penetrating neck injury follows basic tenants of trauma care. In addition to the standard resuscitation guidelines, extra caution must be taken to ensure cervical spine stabilization. Mild Trendelenburg position may help prevent air embolization in cases of suspected venous injury. Maintaining airway patency by avoiding accumulation of secretions such as blood and vomitus should be the physician’s central goal. Moreover, by assessing the location of injury, the etiology of the airway obstruction may be determined. Management of a compromised airway involves a spectrum of techniques ranging from a simple chin lift or jaw thrust to the establishment of a surgical airway. Indications and caveats for these maneuvers will be discussed. Assessment of breathing, the second phase of resuscitation, is very important in patients with neck trauma. Stridor may indicate severe airway obstruction secondary to fluid, edema, extrinsic compression of the trachea, or primary injury of the trachea or larynx. Breathing difficulties may result from asymmetric chest movement, as might occur after a pneumothorax or hemopneumothorax, secondary to a Zone I or II injury. Stabilization of the patient’s circulatory status is the third tier in the evaluation process, although this is typically performed simultaneously with the first two. Direct pressure is usually ‘the primary means of hemorrhage control, although Zone I injuries may require emergent left anterolateral thoracotomy or median sternotomy. After a rapid but thorough patient history is obtained, the wound is examined. Under no circumstances should probing be performed. Clot dislodgement and uncontrollable hemorrhage may occur even 6

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in the most innocuous wounds. Examination should include gentle palpation of the affected area, noting swelling, crepitus, tenderness, and tracheal deviation. A thorough vascular and neurological examination is essential as is the evaluation for any potential skeletal trauma. The controversy surrounding this algorithm involves the diagnostic pathway in the hemodynamically stable patient. The debate between mandatory exploration and selective observation stems from those surgeons who question the validity of exploration in all patients with injuries penetrating the platysma muscle. Multiple studies support mandatory exploration indicating minimal morbidity for negative procedures. These studies also warned of a significant incidence of injury in patients with clinically negative physical examinations. Nonetheless, in an attempt to initiate alternative means of detecting injury, surgeons began to question the high incidence of negative neck explorations. Arteriography became the “gold standard,” proving to be an accurate modality in this situation. Further studies were needed, however, to ensure against aerodigestive trauma as well. These extra diagnostic maneuvers prolonged the length and increased the cost of diagnostic evaluation, forcing many surgeons to continue their support of mandatory exploration. With the validity of arteriograms well established, the use of diagnostic techniques for studying other organs was initiated. Esophagography and panendoscopy were the mainstays in this area. Proponents of selective management published a number of reports supporting selective nonoperative management for patients lacking clinical symptoms and signs of injury. Support for nonoperative therapy continued, as data relative to the decreased cost and length of hospitalization was presented. The addition of well-controlled prospective studies, however, did question the safety of selective observation. One prospective study on the efficacy of barium esophagography including flexible and rigid esphagoscopy, found that in patients with equivocal barium studies, rigid as opposed to flexible esphagoscopy should be performed to exclude esophageal injury. Although inherent controversy surrounding management of patients with penetrating cervical trauma exists, consideration of the zone of injury will aid in assessing these patients. For Zone I injuries, preoperative arteriography in the stable patient may guide the surgical approach. In Zone III injuries, arteriographic results may influence both the need for surgery as well as the procedure to be performed. Zone II lesions, conversely, may be assessed by selective management or exploration which offers clear visualization at this level and avoids a prolonged and costly diagnostic work-up. Patients with negative exploration may be considered for discharge fr*om the recovery room. Injuries from gunshot wounds, either singular OI multiple, are often best evaluated b-y arteriography even if exploration is planned. Their course is not alwa.ys predictable and the Curr

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added information obtained from the arteriogram may assist the surgical procedure. It is important to remember, however, that if a nonoperative plan is to be adopted, injuly to the aerodigestive system must be excluded. Prior to the surgical procedure, cooperation between the surgeon, anesthesiologist, operating room team, and patient is essential. Maneuvers which elevate blood pressure or cause agitation should be avoided. Rapid induction of anesthesia may be preferable to awake techniques. Skin preparation should be gentle to avoid dislodging any clot that may be present. Nasogastric placement, which may increase pressure during insertion, should be withheld until after induction of anesthesia. Awareness of the management precautions necessary in these trauma patients (cervical spine immobilization, aspiration prevention, possibility of anomalous or distorted airway anatomy), are crucial points for the anesthesiologist. Experience with fiber optic intubation should be part of their armamentarium when caring for this select group of patients. The surgical approach to penetrating neck trauma also depends on the zone of involvement. Zone II and III injuries are addressed in a manner typical of elective carotid surgery. Access to the vertebral artery may also be achieved by this procedure. Visualization of injuries in the distal internal carotid artery may be enhanced by anteriol subluxation of the mandible. Injuries at the base of the neck may be accessed rapidly through a median sternotomy, whereas a left anterior thoracotomy may control hemorrhage from the proximal left subclavian artery. Both incisions may be modified to adequately expose other areas of the vessels. In the stable patient, an incision along the medial aspect of the clavicle will expose the proximal right subclavian artery and both subclavian veins. Again, extension of these incisions may be performed to evaluate the right or left neck. With proximal and distal control of the injured vessel, repair is usually accomplished without the use of either intraluminal shunts or heparin. Saphenous vein for interposition or patching purposes should be readily available from a previously prepared site. Completion arteriograply must be an integral part of the operative procedure. The repair of injuries to the extracranial carotid artery is complicated by concern for the neurologic status of the patient. Generally, injuries to patients with normal or minimally abnormal neurologic examinations should be repaired. Because of the concern about converting an ischemic to a hemorrhagic infarct, the controvkrsial group consists of patients with moderate or dense pre-operative neurologic deficits associated with interrupted carotid blood flow. However, death after revascularization is thought by some to be secondary to cerebral edema as opposed to infarction. Another concern which makes the value of I-evascularizatic,n uncertain is cerebral me8

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tabolism and autoregulation, and the extent of collateral circulation. Most investigators agree that, except in circumstances of profound neurologic injury, emergent revascularization offers the best opportunity for survival and acceptable neurologic recovery. While access to the various organs within the neck may be similar, repair of individual organs requires specific techniques. Tracheal and laryngeal injuries may be repaired with a single layer of absorbable suture, saving permanent monofilament material for closing involved cartilaginous structures. Drainage and administration of antibiotics are also recommended. Pharyngeal and esophageal injuries are managed similarly to tracheal and laryngeal injuries. Many surgeons advocate, however, a two-layer closure in the repair of the former. In both groups of injuries it is appropriate to reinforce the repair with local muscle flaps. Newer techniques for the control and treatment of relatively inaccessible areas of the cervical vascular tree include the use of fogarty balloon catheters and transcatheter embolization. Fogarty catheters may be used to control (by occlusion) hemorrhage from distal internal carotid artery injuries. Moreover, detachable endovascular balloons have been used as a permanent solution for this problem. Although transcatheter embolization using many agents has gained acceptance in recent radiology and neurosurgery literature, the possibility of partial or inadequate treatment must be realized. Cervical venous injuries rarely cause problems. Basic vascular techniques are used in repair of these injuries, but ligation is recommended if more extensive management is indicated. Air embolization comprises the major problem related to this injury. Specific management is also indicated for injuries to the thoracic duct, cranial nerves, and salivary and endocrine glands with the crucial element being appropriate recognition. Infectious complications commonly occur when injuries have been overlooked. As in other areas of trauma surgery, administration of perioperative antibiotics is recommended. Specific coverage and treatment is indicated for cervical abscess, fasciitis, and cervical osteomyelitis. In brief, the care of patients with penetrating trauma to the neck is an exciting task, with management and therapeutic techniques constantly evolving. The basic surgical principles continue to serve as the foundation on which treatment is performed. Resuscitation, history and physical examination, followed by a diagnostic program are all essential elements of the treatment plan. Deciding on the mode of management depends on the stability of the patient, the mechanism and the zone of injury, the results of diagnostic evaluations, and the philosophy of the individual surgeon.

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Erwin R. Thai, M.D., graduated from the Ohio State University College of Medicine in 1962. His internship and residency in general surgery were completed at Parkland Memorial Hospital on the campus of Southwestern Medical School in Dallas, Texas. Following his training, he joined the faculty at Southwestern, where he is currently Professor of Surgery. His major area of interest in general surgery lies in the$eld of trauma. He is the immediate Past Chairman of the American College of Surgeons’ Committee on Trauma.

Dan M. Meyer, M.D., received his undergraduate and medical degree from the University of California at Los Angeles. His postgraduate training in general surgery was completed at Parkland Memoral Hospital in Dallas, Texas. During this period, he also spent a year doing research in the surgical cardiovascular laboratory. Following his residency, he continued his training at the University of Texas Southwestern Medical Center in Dallas with a fellowship in thoracic and cardiovascular surgery. He is currently an Assistant Professor in the Division of Cardiothoracic Surgery at Southwestern Medical School. 10

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PENETRATING

NECK

TRAUMA

Penetrating injury to the neck comprises 5% to 10% of all trauma cases, a relatively small fraction of the overall trauma experience. Many controversies regarding the diagnosis and appropriate management of these often occult injuries still need resolution. In spite of the relatively small fraction of total body surface area, the neck contains anatomic structures representing virtually every physiologic parameter, all of which are subject to injury. Whereas aggressive operative management was formerly the accepted mode of therapy, improvement in diagnostic procedures and experience with nonoperative treatment have caused many individuals to reevaluate and formulate new management principles.

HISTORY The first recorded treatment of a cervical vascular injury occurred when Ambrose Pare arrested the hemorrhage from a bleeding left carotid artery caused by an epee wound in 1522.’ Operative management was the mainstay of therapy when Fleming, on board the H.M.S. Tonnant in 1803, ligated the common carotid artery after one of the sailors attempted suicide.” This practice of ligation was continued in the 1800s in spite of mortality rates as high as 60%. Impiovement was gradual and although mortality decreased with time, reports continued to produce less than encouraging results. Ligation continued to be the procedure of choice during World War I, although in a series reported by Makins,” 30% of the patients had a postoperative neurologic deficit. It was not until World War II, as reported by Lawrence and associates4 that repair of the carotid artery was attempted. Experience gained in the Korean War” and the Vietnam conflict6 began to demonstrate the benefits of early repair. With improvement in pre- and perioperative care, as well as the advent of modern operative techniques, mortality continued to fall to 15% during the Vietnam War and finally to a current level varying between 2% and 6% .‘, ’ Although the emphasis on operative therapy for penetrating injuries to the neck was fostered in the Vietnam era, attention has now Curr

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turned to nonoperative management of many of these patients. The advocates of mandatory exploration defend their position by stating that penetrating neck injury frequently causes significant, albeit often occult, injuries. Moreover, the combined morbidity and mortality following negative findings on neck exploration are negligible, when contrasted with the complications that frequently accompany a missed injury. The proponents of mandatory exploration also note that the hospital stay is similar in length for patients operated on when compared to those observed expectantly. Finally, mandatory exploration reduces the total physician time needed to safely observe acutely injured patients as well as limits the number of diagnostic studies obtained. Advocates of selective observation argue that mandatory exploration is a practice based on military injuries resulting from highvelocity missiles-a mechanism different from today’s stab wound or low-velocity-missile wounds.” They reflect on recent experiences that produced lower rates of exploration for which no injury was found at operation, lower costs, and equally satisfactory results, based primarily on better diagnostic procedures, namely, arteriography, endoscopy, and contrast-enhanced radiography. Patients with obvious surgical indications, such as significant or active bleeding, vascular occlusion with intact neurologic function, and penetration of the aerodigestive system, are clearly not candidates for nonoperative management. Patients with isolated zone 11 injuries (defined in next section) may also be better served by operative exploration rather than exhaustive and expensive diagnostic studies. This area is easily accessible and there is low risk for exploration. In contrast to zone II injuries, zone I injuries (base of the neck1 and zone III injuries (base of the skull1 offer more difficult surgical challenges and, therefore, as a minimum, arteriography is generally recommended. A positive finding on arteriogram is usually followed by surgical intervention, although some authors now advocate selective nonoperative management for minimal vascular injury, as may occur in vertebral artery injuries.‘” Patients with negative findings on angiogram frequently are observed if no other injuries are present. From an economic standpoint, opinions are polarized regarding the monetary advantage of selective management versus mandatory exploration. Merion and coworkersL1 reported a significant mortality related to delayed operation in patients initially observed for penetrating cervical trauma. To avoid the incidence of missed injuries, selective evaluation has been advocated. While some investigators” reported a savings of $2,000 per patient treated nonoperatively, others believe mandator-y operation may have economic advantages. Bishara and associates” reported a 53% incidence of normal findings in patients following mandatory exploration for zone II neck wounds. 12

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These authors suggest discharging these patients immediately after surgery without formal admission to the hospital. This outpatient surgery has the advantages of significant cost savings, often with less morbidity. Another controversial issue concerning the care of patients sustaining penetrating cervical trauma relates to the concept of the trauma center. Recent data indicate that less morbidity and mortality occur when patients are treated in an appropriate trauma facility.” Resuscitation, evaluation, and definitive treatment are better accomplished by individuals who frequently see these problems and have a large experience from which to individualize care. Many patients with seemingly trivial injuries may indeed have life-threatening problems. As with all trauma patients, the immediate postinjury period may be misleading in regard to the extent and severity of injmy. The acutely injured patient with penetrating neck trauma, rcgardless of initial findings, should be taken to a trauma center.

ANATOMIC

CONSIDERATIONS

The more immediate life-threatening cervical injuries involve the vascular and neurologic structures in the neck. Other serious injuries may involve the larynx, trachea, pharynx, and esophagus. Involvement of the surrounding soft tissue, th-yroid and parath.yroid glands, the lower cranial nelves, and the brachial plexus, and the rare thoracic duct injur;v must also be considered. Anatomically, the neck can be divided into either triangles OI zones. The two major triangles of the neck are located anteriorly and posteriorly. The anterior triangle is bounded by the midline of the neck, the lower border of the mandible, and the anterior border of the sternocleidomastoid muscle (Fig 1). Within this triangle can be found important vascular and aerodigestive structures. The boundaries of the posterior triangle are the middle one third of the clavicle, the posterior border of the sternocleidomastoid muscle, and the anterior border of the trapezius muscle. The more common anatomic classification when describiIlg cervical injuries stratifies the neck into three zones situated in horizontal planes (Pig 21. Zone 1 encompasses the thoracic outlet and extends from the base of the neck located at the sternal notc:h to the cricoid cartilage. Penetrating trauma in this area is associated with a higher mortality because of the risk of injury to major \,as(:ulaI~ and intrathoracic structures such as the proximal common carotid artery, the vertebral artery, the subclavian artery, and other major thoracic: vessels; the lungs; upper mediastinum; esophagus; trachea; thyroid; and thoracic duct. Zone II extends from the cricoid cartilage cephalad to the angle of the mandible. Potenlial injtrries include the carotid artery, \r:rtebral

FIG 1. The anterior and posterior triangles of the neck. (From Jurkovlch GJ, The Neck, in Moore EE (ed): Ear/y Care of the injured PaBent, ed 4. Philadelphia, BC Decker, Inc, 1990, p 127. Used by permission.)

artery, jugular vein, trachea, larynx, esophagus, and spinal cord. Zone II injuries are the most common and generally are associated with a lower mortality rate than found with zone I injuries. This difference in mortality results from the ease of obtaining local control of major hemorrhage and the ability to gain rapid and complete exposure of the anatomic structures in this area. Zone III is located cephalad to the angle of the mandible and extends to the base of the skull. Structures at risk in this region include the distal internal carotid artery, the vertebral artery, the salivary glands, pharynx, and spinal cord. Injuries in this area may be difficult to identify and repair. Additional exposure can be accomplished by performing anterior subluxation of the mandible and wiring the jaws. Utilizing this technique, it is possible to gain access to an additional 1 to 2 cm of the distal internal carotid artery (Fig 3). Surgical exposure in the neck is based on many important anatomic landmarks. The platysma muscle is the first structure encountered beneath the skin. Penetration of this muscle, in the past, has been an indication for surgical exploration and hence it serves as a key landmark. Management of patients with injuries that penetrate 14

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FIG 2. 3n~cal Jurkovich -Jelphla.

zones of the rieck. Snaueo area refers to zone /I In some cIasslficdw:ls (From GJ: The Neck, in Moore EE ted) Early We of The /n/wed Patient, ed 4. 2h1laBC Decker, Inc, 1990. p 127 lised by permssion )

this muscle requires metlcuious evaluation and mature clinical judgment. The platysma covers the entire anterior triangle and the anteroinferior aspect of the posterior triangle. The muscle is extremely thin, is covered by a superficial fascia, and overlies the deep cervical fascia (Fig. 41. The deep cervical fascia serves as a supporting framework for the muscles, vesseis, and viscera of the neck, It is divided into three parts; the investing layer, the pretracheal layer, and the prevertebral layer. The investing layer encircles the neck, splitting to envelop the sternocleidomastoid and trapezius muscles. The pretracheal layer adheres to the thyroid and cricoid cartilage and extends into the chest where it fuses n,*ith the pericardium. This ?aver surrounds the thvroid gland and binds it to the laynx. The d prevertebral layer covers the prevertebral muscles ilongus capitis, Iongus cervicis, scalenus anticus, scalenus medius, levalor scapulae, and splenius capitis!. Extension of this layer forms the axillary sheath that invests the sttbclavian artery as it emerges from between the scalenus anticus and scalenus medius muscles. The carotid sheath envelopes the common and internal carotid arteries, the inand fuses anteriorly with the ternal jugular vein, and vagus nerves, Curr

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FIG 3. Additional exposure of the distal internal carotid artery obtained by subluxatlon of the mandible (arrow). (From Thal ER: Injury to the Neck, In Mattox KL, Moore EE, Feliciano DV (eds): Trauma, ed 2. Norwalk, Conn. Appleton and Lange, 1988, p 307. Used by permlssion.)

pretracheal and investing layer zf the deep cervical fascia, and behind with the prevertebral layer. While surgical exposure of the carotid artery is well described, exposure of the vertebral artery is less well appreciated. Recent attention has been drawn to this vessel as the frequency of recognized vertebral artery injuries has paralleled the increased use of four16

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Cross section view of cervical DA. At/as of Surgicai Anatomy sion.)

‘ascidi &nes (From Gray SW, Skandalakis >E, IvlcCltisky Mtimore, Wi!liams & Wilkins, 1985, p 15. Used by permis-

vessel arteriography for penetrating cervical trauma. The vertebral artery is the first and largest branch of the subclavian artery and is divided into four segments (Fig 5). The first segment of the vessel passes upward and posteriorly through the foramen of the transverse process of the sixth cervical vertebra. It is contiguous with the vertebral and internal jugular veins. The second and longest segment ascends through the foramen of the transverse process of the upper six cervical vertebrae. The third segment passes horizontally, posteriorly, and medially behind the lateral portion of the atlas. Finally, the fourth segment is the intracranial portion, passing through the foramen magnum to form the circle of Willis with the internal

FIG 5. V, through V, denotes the four segments of the vertebral JA J Trauma 1988; 28:1008 Used by permissIon )

artery

(From

Reid

JDS,

Welgelt

carotid artery after it joins the vertebral artery from the opposite side. Surrounding the distal portion of the vessel is a large venous plexus, which, if injured, results in significant blood loss. MECHANISM

OF INJURY

Penetrating neck trauma is most often due to either stab wounds or gunshot wounds, although other sharp projectiles may be responsible for injury. Despite the fact that soft tissue, airway, and digestive structures are frequently injured, the most common cause of death and disability relates to vascular injuries with attendant exsanguination, stroke secondary to embolism or vascular occlusion, or neurologic injury secondary to spinal cord involvement. One of the major problems associated with the management of penetrating neck trauma is the assessment of high-velocity-missile 18

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wounds. In this situation, there is significant tissue destruction related to the energy of the projectile; hence, the formula K = M mv? where K = kinetic ener@, m = mass, and v = velocity, must be COIIsidered. Accordingly, as the velocity of the missile doubles, the energy produced increases four times. Doubling the mass, however, only doubles the kinetic energy. Furthermore, the extent of injury increases as a result of expansion or fragmentation of the missile within the neck. The theoretic wounding potential of a projectile, or the kinetic energy that must be produced by the missile to cause tissue damage, increases with changes in velocity far out of proportion to changes in mass or weight. Similarly, the velocity of the projectile at impact and the subseyuent rate of deceleration of the bullet determines the energy that is released to the target area. Ln evaluating patients with penetrating injury to the neck, information as to the source of the wounding agent is important. One must consider, however, the path of the missile. While bullets may travel in a straight line, deflection often occurs in various surrounding tissues, especiall-y if bone is hit. Low-velocity missiles such as shotgun pellets I< 2,500 feet/sect are more prone to erratic pathways, as they tend to follow tissue planes or the path of least resistance. Missiles may spontaneously fragment or may fragment after contact with other tissue, thereby propelling secondary missiles. Another factor related to the release of kinetic energy is associated tumbling of the missile. Moreover, the angle at which the bullet travels through the tissue determines the displacement of kinetic enera and therefore contributes to tissue damage. Regardless of the etiology of this kinetic ener@, whether it be velocity, mass effect, or characteristics of the projectile, the distribution to the surrounding tissue in the neck causes a temporary cavitation. The higher the energy, the greater the cavitation and associated tissue damage.” ” Therefore, it is important to note that blast effect and significant injury may occur with wounds that appear to be superficial. Rearing this in mind, complete e\.aluation of these patients must include a broad area of potential involvement. This cavitation effect OC~:LWS because of the missile’s abilit?! to produce a temporary cavity in addition to the permanent cavity formed by the actual path of the IjulIet [Fig 6). The actual dimensions of the temporary cavity (shape and size) depend on bullet velocity, diameter, shape, size, tumbling potential, and fragmentation etfect. The cavitation effect is thought to be due to elastic recoil of the tissue, which causes air to be trapped by negative pressure.” With an increase in the velocity of the projectile, the size of the cavity and the formed pressure wave will increase, potentially causing damage out of proportion to the bullet cliameter. Therefore, missile wounds ma>’ penetrate more deeply than stab wounds and produce an area of

FIG 6. Cavitation effect of missiles. Open arrow denotes temporary cavity. (From Barach E, Tomlanovich Used by permission.)

permanent M, Nowak

cavity; closed R: J Trauma

arrow 1986;

denotes 26:231.

damage extending beyond the actual missile tract, secondary to this cavitation effect.17’ I8 This concept, however, is not accepted by all investigators.1s Another consideration in the evaluation of penetrating cervical trauma relates to missile emboli. An intravascular migratory bullet is a rare complication, but may occur with either direct penetration of a vascular structure or direct entry into the heart. Missile emboli have been reported as long as 14 years after initial injury and the mechanism is probably vessel erosion rather than direct injury at the time of the initial incident? There are many case reports of 20

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both arterial and venous cmbolization. Abdo and coIIeagues,Z1 from Beirut, reported a shotgun wound to the neck in which a pellet embolized from the internal carotid artery to the middle cerebral artery. This patient developed progression of neurologic symptoms after his injury. A computed tomography (CT) scan showed a left frontal lobe infarction, which accounted for the new onset of his right-sided weakness and motor aphasia that occurred 2 days after the injury. A subsequent carotid arteriogram showed the pellet located in the left frontotemporal branch of the middle cerebral artery. The patient was treated conservatively with complete resolution of his neurologic deficits. Mattox and associates,zl in discussing the management of missile embolization, focused on preoperative radiographic localization. Changes in missile localization occur as a result of gravity, the weight of the bullet, or positional change of the patient. If this occurs, it is recommended that the projectile be removed. The presence of venous air emboli following fatal head and neck wounds was recently reported by Adams and Hirsch.‘” Air emboli in both the right side of the heart and pulmonary artery were found at autopsy in 16 patients ~ollo~~~ng either shotgun or gunshot wounds of the head and neck as well as in patients with blunt head trauma. The venous air emboli were thought to QCCEII’as a result of a central progression of air from the venous en@ site caused by the negative intrathoracic pressure gradient created by the inspiratory effort. The authors stated that x-ray uation of the chest in addition to the head and neck may be he 1 in the early management of these patients. Penetrating injury may occur due to blunt trauma. Whereas different mechanisms such as deceleration, &earing, and tearing forces exist with blunt trauma, penetration from adjacent sharp objects may also occur. Careful evaluation on physical examination will generally reveal these injuries.

RESUSCITATION

The evaluation and management of patients sustaining penetrating neck trauma follow the basic principles of trauma care. Airway control is the initial concern and highest priority of care, a point that cannot be overemphasized when dealing with any patient population. In the prehospital setting, the suspicion or possibility of cervical spine injury mandates stabilization to prevent further injury or deterioration. Sandbags may be more functional, but afford little protection from violent movement. A cervical collar is rigid, but may interfere with the examination process. Its use with penetrating neck

trauma is not recommended unless there is evidence of cervical instability. It is important to keep the patient in a supine position and to be prepared to suction the airway if vomiting occurs. If venous injury is suspected, a very slight Trendelenburg position may aid in the prevention of air embolism. Airway patency can be rapidly evaluated by focusing on the location of injury, degree of upper or lowe airway obstruction, and assessment of respiratory effort. Impairment of mental status and neurologic injury may further complicate airway function. Other aspects related to potential airway obstruction include the presence of blood or vomitus in the pharynx, progressive cervical swelling from a pharyngeal or esophageal injury, and soft tissue swelling secondary to the primary injury. At this point, the assessment of the patient’s oxygenation and ventilation may indicate a need to establish a more adequate airway. Basic life support maneuvers such as a chin lift or jaw thrust may overcome a simple upper airway obstruction. Failure of this maneuver should be followed by the insertion of a nasal trumpet or nasopharyngeal tube. Removal of foreign bodies or secretions by suction may be beneficial. If these procedures do not resolve the problem, a nasotracheal or endotracheal airway is immediately required. In-line manual cervical support performed by another member of the resuscitation team may allow direct orotracheal intubation with minimal neck hyperextension. It is not necessary, and in fact may be detrimental, to apply cervical traction at this point. It is important that all patients with significant neck trauma be assumed to have a cervical spine injury until proved otherwise. Another danger associated with endotracheal intubation relates to the possibility of converting an apparently minor airway obstruction into that of a life-threatening one. This may occur when multiple blind attempts at intubation result in the raising of a mucosal flap, which in turn causes an airway obstruction. Care must be taken to evaluate the integrity of the larynx prior to intubation, as a fractured larynx is a relative contraindication for endotracheal manipulation. This injurv is more common with blunt trauma, but does occur with penetraiing injury as well. Intubation of a patient with a fractured larynx may precipitate a complete transection or create a false passage. If a fractured larynx is present, one should secure a surgical airway by performing a tracheotomy. If an airway cannot be secured by the standard oral or nasal route, efforts must rapidly be turned toward performing the necessary surgical procedures designed to cannulate the trachea. This is most often successfully accomplished by establishing a cricothyroidotomy or, in children, performing a needle jet cricothyroidotomy. Indications for a surgical airway include the inability to secure an airway by conventional means or concomitant major maxillofacial trauma, especially involving the floor of the mouth or the base of the tongue. 22

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The second phase of resuscitation, assessment of breathing, is particularly important in patients with neck trauma. The patient should be evaluated for evidence of strider, although this may be absent in cases of severe airway obstruction secondary to diminished airflow. Stridor may also mark airway obstruction secondary to tracheal or laryngeal injury, with respiratory muscle retraction being evident in the supraclavicular, intercostal, and suprasternal locations. Neck wounds caused by long objects may cause acute changes in the chest. Unequal breath sounds and as_ymmetric chest movement are signs of inadequate ventilation, possibly caused by a pneumothorax or a combined pneumohemothorax, as may be the case in injuries penetrating zones I and II. Tension pneumothorax should be sought and relieved as soon as possible. Following, but generally simultaneously with, assessment of the airway and breathing, attention is directed toward evaluation and stabilization of the patient’s circulatory status. Fortunately, most bleeding incurred from penetrating neck wounds can be controlled by direct pressure at the site of the injury. This position can be maintained until the patient is intubated and the surgical field is prepared. Random placement of clamps in the region of the wound must be avoided, as blind clamping may injure vascular and nervous structures. Hemorrhage from a zone I neck wound may be more difficult to control, as exsanguination may occur within the chest cavity. Intravenous access should exclude the ipsilateral upper extremity because of the possibility of internal jugular vein or subclavian vein injuty. When confronted with major intrathoracic hemorrhage an emergent anteriolateral thoracotomy or median sternotomy for direct control of the injuly may be indicated.

A rapid, accurate history obtained from the patient, paramedics, family members, or other witnesses may supply important information regarding the mechanism of injury, the patient’s condition prior to arrival at the hospital, an assessment of the amount of blood loss, and the likelihood of other associated injuries. Questions addressing difficulty with breathing, swallowing, or phonating, as well as a history of hemoptysis or hematemesis, are important. A complete neurologic history, including a focus on any upper extremity dysfunction in patients with trauma to the lower neck, is essential. A thorough history is followed by a detailed physical examination that first assesses the airwa.v, but being careti not to focus simply on the cervical region. Careful examination of the chest should be performed to ensure against associated thoracic injury such as pneumothorax, hemothorax, or paralysis of the diaphragm. Inspira-

tory and expiratory chest roentgenograms are obtained to rule out subtle injuries. On close examination of the neck, one should observe for any swelling, asymmetry, or discoloration, all signs indicative of vascular injury. If bleeding occurs, it is important to ascertain whether or not it is pulsatile in nature. The wound itself, no matter how innocuous it may appear, should not be probed for fear of dislodging a clot or causing hemorrhage that often cannot be controlled. Moreover, as previously stated, attempts at clamping within the depth of a bleeding wound should be discouraged because of risk of injury to adjacent structures as well as the vessels themselves. If bleeding occurs, direct pressure should be applied for control. Palpation should be performed, noting areas ‘of tenderness, crepitus, subcutaneous emphysema, or tracheal deviation. Vascular integrity is assessed by palpating for pulses and thrills as well as auscultating for bruits. It is important to note that a normal vascular examination may be present in 10% to 30% of patients with vascular injury. The posterior aspect of the neck should be evaluated with the same degree of concern as the anterior and lateral aspects, with special attention directed toward potential skeletal injuries. A thorough neurologic examination completes the evaluation. Clinical findings associated with specific cervical injuries are listed in Table 1. Important physical findings in patients with potential vascular injuries include diminished carotid, superficial temporal, or ophthalmic pulsations; presence of bruits; or a cervical hematoma (noting size and progression). Vascular trauma may also be manifested by evidence of neurologic deficits consistent with a hemispheric stroke due to either thrombosis or embolization. Classic findings would include hemiparesis, aphasia, or monocular blindness. One must be aware that although extremely important, the physical examination is not the “gold standard” when evaluating neck injuries. McCormack and Burch” found that 38 (42%) of 91 patients with a physical examination suggestive of vascular injury had normal arteriograms, whereas 20% of patients with no clinical signs of injury had positive findings on the studies. Laryngeal trauma, although more common with blunt injury, may produce characteristic physical findings. The examiner should be cognizant of the possibility of fracture to the thyroid cartilage, subluxation of the arytenoid cartilage, or dislocation of the cricothyroid joint. Patients may have local tenderness, subcutaneous emphysema, shortness of breath, or changes in phonation. As previously noted, endotracheal intubation is potentially hazardous because of the possibility of creating a false passage, thereby leaving the patient without an adequate airway. Nerve injury following penetrating cervical trauma may have an array of possible physical findings, including deviation of the tongue toward the ipsilateral side of injury, dysfunction of the oropharyn24

Cur-r

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1992

TABLE Clinical

1. Findings

Associated

with

Spwific

(krvical

Injuries’

geal muscles causing drooping of the corner of the mouth, Horner’s sUyndrome, cervical sensor? deficits, or extremity deficits as a result of a brachial plexus injury. After a complete history and physical examination, a diagnostic plan should evolve and be dependent on the location of the injury and the stability of the patient. In the unstable patient, resuscitation and local control of bleeding should be attempted while preparing for emergent operation. Injuries located toward the base of the neck on the left side are best managed by performance of an urgent left anterior thoracotomy in the third to fourth intercostal space for control of hemorrhage. Conversely, injuries at the base of the neck in the midline or on the right side are best approached through a median sternotomy (Fig ‘7). More commonly, patients are stable, allowing the physician to pursue an orderly diagnostic workup. The controversy between selective nonoperative management versus aggressive mandatory exploration dictates what type of evaluation is undertaken. On one side are those who support mandator-y exploration for all wounds that penetrate the platysma muscle. In contrast, the alternate camp promotes selective obsefalation following a complete diagnostic eval-

COMMON RIQIT suBCL6/lAN

CAROTID

ARTE

VESSE

LEFT

~~I~CLAWAN

vEssm

EXTENSION FOR INNOMINATE ARTERY

LAP-INNOMINATE.PROXlMAL EFT !iWSCLAVlAN AND LEFT OMMON CAROTID ARTERIES

EMERGENCY CONTROL OF RIGHT SUBCLMAN AND INNOMINATE ARTERIES

MERGENCY CONTROL DF IWOXMAL EFT SUBCLAVIAN ARTERY INNOMINATE ARTERY, PROXIMAL LEFT COMMON CAROTID

FIG 7. lncwons used for operative exposure of Injuries located at the base of the neck. (From Snyder WH 111, Peripheral and Abdominal Vascular InjurIes. In Rutherford RB (ed). Vascular Surgery, ed 2 Philadelphia, WB Saunders Co. 1984, p 477 Used by permission.)

uation, which may be limited only to the history and physical examination or may include routine endoscopy and arteriography. The philosophy of early mandatory exploration of penetrating cervical trauma comes from a study by Fogelman and Stewart,‘” who reviewed 274 patients following penetrating neck trauma. The group that underwent early exploration had an operative mortality of 6.0%, while those explored late or not at all had a mortality of 35%. In the 15 patients who underwent operation without signs or symptoms of cervical injury, the overall mortality was 4%. In further support of this method of management, Sheeley and associates”” reviewed 632 patients, over half of which underwent exploration whereas 125 patients were observed. There were 142 explorations with negative findings, with no mortality or significant morbidity. The 35 deaths (5.5% operative mortality in this study support the premise that there is minimal risk when performing neck exploration as a diagnostic and therapeutic modality. Saletta and coworkersY reported a retrospective series of 246 patients with neck trauma. With a policy of mandatory exploration, 156 patients (63%) had negative findings on exploration, with a morbidity of less than l%, no mortality, and a mean duration of hospitalization of 3 davs. In the 90 patients with positive findings on exploration, the investigators reported a morbidity of 8%, a mortality of 9%, and a mean duration of hospitalization of 8.5 days. Thirteen (14.4% J of 90 patients with positive findings on exploration had clinically negative results on physical examination. There were 7 internal jugular vein injuries, 2 hUypopharyngeal injuries detected bv endoscopy, 1 esophageal injury, and 1 each internal carotid injury, -innominate artery, and innominate vein injury diagnosed by arteriography in this group. More recently, Bishara and associates’” reviewed 110 patients with zone II injuries. Their study 26

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was limited to zone II as many surgeons advocate routine preoperative arteriography on stable patients with penetrating trauma to zones I and III. Perioperative evaluation included careful physical examination, plain cervical radiographs, and arteriography. Although 53% of their patients had normal findings at exploration, 33% did have injuries to vascular structures and 14% were found to have nonvascular injuries. Twenty-three percent of the patients with no clinical evidence of injury had positive findings on exploration. The authors reported two false-negative results based on arteriograms. These investigators, based on the low incidence of minor complications 15%) in the group with no injuries, recommended routine exploration for patients with penetrating cervical trauma. As surgeons began to note the high tieyuency of procedures in which no injuries were found, arteriography as a “gold standard”“’ became more commonly used as a diagnostic study. Carducci and associates” focused on the importance of vascular injmy in patients sustaining penetrating cervical trauma and found large vessels tarteries and veins) injured in 44.4% of their patients. Moreoever, they identified a significant rate of air embolism associated with cervical venuus injuries. In 18% of their patients, they found arterial injuries, of which 33% were corn1~101~ carotid, 15% subclavian, and 14% external carotid. These authors also referred to the series from Flint and associates”’ on injuries at the base of the neck, in which 86 arterial injuries were noted with a mortality of 12.5%. In zone I, Flint and associates found the carotid artery, along with the subclavian, injured most often, each comprising 18% in their series. Injuries to the innominate and vertebral arteries were considerably less freyuent, comprising only 3% each in their series. Thirty-two percent of their patients with vascular injuly had no clinical evidence on physical examination, although 35% of the patients with carotid injuries had a lateralizing neurologic deficit. Late complications included traumatic aneurysms and arteriovenous fistulae. Hiatt and associates.“’ reported a series of over 100 cervical injuries, 70% of which appeared normal on arteriograms and were therefore observed without complications. Approximately 30% appeared abnormal on preoperative arteriograms, with 26 184% I of 31 patients having operative findings that correlated with the arteriographic findings. In 2 patients, however, arteriography underestimated the extent of arterial injury. Also, in 3 patients with carotid lacerations, a significant venous injury that was present was not diagnosed on preoperative studies. In an attempt to further decrease the rate of negative findings on neck exploration, many groups serially added more steps to the preoperative evaluation. Focusing on the asymptomatic patient, Jurkovich and coworkers.” reviewed 100 consecutive patients, 53 of whom were managed selectively based on the absenct> of physical signs of injury or the suri:urr

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27

geon’s preference. Arteriography, fluoroesophagography, and aerodigestive tract endoscopy were performed, with a diagnostic yield of 22.6% (12/53). Only 5 (9.4% J of 53 patients in this group actually benefited from the additional diagnostic studies. Arteriography detected most of the injuries in their series. These authors recommended using these ancillary studies selectively according to the anatomic zone of injury. For injuries to the base of the neck or thoracic outlet that may be occult, chest x-ray, arteriography, and fluoroesophagography should be considered. Conversely, zone II injuries are, according to these authors, rarely occult and therefore they recommend nonoperative observation so long as the patient remains asymptomatic. Endoscopy and esophagoscopy proved unrewarding in their experience and, subsequently, they recommended operative exploration in cases where clinical suspicion points toward an injury to the aerodigestive tract. Similarly, they considered zone III injuries to involve the aerodigestive system infrequently and thus endoscopy would be of little yield. Arteriography, however, is worthwhile to diagnose high internal carotid arterial lesions. With recognition of the validity and reliability of arteriography in identifying injury to the vascular structures, similar attempts were made to study other organs for potential injury. The premise was that if diagnostic studies reveal no injury to the major organs, selective nonoperative management might be more palatable, even to those who advocate an aggressive operative approach for all patients with penetrating neck trauma. This led to the more widespread use of panendoscopy and esophagography. With more experience and confidence in these techniques, additional interest in supportive management of these patients with negative or even selectively positive findings on arteriographic studies became apparent. One of the early series evaluating the use of selective management in penetrating cervical trauma was a prospective study by Narrod and Moore.” In a group of 77 patients, 48 (62%) underwent exploration based solely on clinical findings, with 85% having major injuries. Of the remaining 38% of the patients who were observed, ancillary diagnostic studies determined no need for operation. Additionally, the average number of hospital days was more in both the group explored and found to have injuries (10.4 days] and those with negative findings on neck exploration (2.8 days), when compared to the group observed (1.8 days). The authors concluded that preoperative arteriography was useful in patients with zone I and zone III injuries and in those patients with multiple zone II injuries. Moreover( they suggested that the addition of esophageal studies was warranted in patients with zone I injuries. Another large study questioning the efficacy of mandatory exploration was by Ayuyao and coworkers,“’ who reviewed 257 patients. They analyzed the treatment pattern over a period of time. Of the 28

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19%~

first 148 patients, 134 (group 11 underwent mandatory exploration. Sixty-nine percent had negative findings on exploration. There was a 5% morbidity and a 3% mortality rate in this group. Because of the substantial number of unnecessary operations, the next 109 patients (group II) were managed selectively. Indications for operation in the group II patients included ll”vpotension, shock fraom neck injury, significant bleeding or expanding hematoma, difficulty swallowing, neurologic deficit, decreased or absent carotid pulses, subcutaneous emphysema, respiratory distress, hemoptysis, or hematemesis. Forty of those patients ultimately required an operation. Nine 11’2%) of the 40 patients had no injur?/ at operation. None of the remaining ti9 patients who were observed required an operation. The mortalihr (5.5%~ and morbidity 15.y0’ > ,(II iti this group were not significantly diiferent from those in group I. Using indications for operation similar to those of Au.yuyao and colleagues, as well as considering the site and trajectory of the bullet plus a time interval between injuly and resuscitation of greater than 6 ~~LII~S, Ordog and associates”” used selective management for gunshot wounds to the neck. Those patients who were stable and lacked ph.vsical signs of obvious neck injury were managed with diagnostic evaluation, which included arteriography and endoscopv. ‘I’ht:.v reported a \‘er?/ low mortality of only 2.7% for their patients. Noyes and associates” ’ reviewed their experience with 193 patients sustaining penetrating neck trauma. Seventy-six patients had mandatory exploration, 5’7 patients were selectively observed, and the remaining 60 patients were explored after some preoperative diagnostic studies. As evidenced by a 50% rate of negative findings on exploration, physical signs and symptoms proved to be an unreliable predictor of injury. Conversely, arteriograph-v 1100% I, bronchoscopy and laryngoscopy (1OOWI, esophagograph.y (90% 1, and esophagoscop-v (SC?% J appearecl quite accurate predictors of injury when compared with routine surgeI?/. The length of hospitalization was shortest in the nonsurgical group; selective management-2 days, negative findings on exploration-42 days, positive findings on exploration-9.5 days. The cost was not markedly different when the price of exploration was compared with that of a cervical arteriogram and panendoscopy. Noyes and coworkers concluded that arteriographv and panendoscopy were appropriate in stable patients without specific signs and syymptoms suggesting injury. In another significant stucly Meyer and associates,‘15 addressing the question of mandatory operation versus selective management, prospectively studied 120 patients with penetrating injuries to zone II of the neck. Preoperative studies included four-vessel and arch arteriography, laryngotracheoscop.y, esophagoscopy, and barium sn.allow. All patients were explored and 24% were found to have injuries. There was a 4.4% inciclenctl of missed injury in the 113 patients who Cur-r Prohl

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1992

29

had preoperative arteriographic studies. These injuries included the esophagus, internal jugular vein, and internal and common carotid artery. Impressed by these missed injuries, the authors warned against selective management of patients with penetrating wounds to the neck. The length of hospitalization for a patient with positive findings on exploration was approximately 10 days, as compared to 3.8 days for those with negative findings on exploration. Their overall morbidity of 6% and mortality of 0.8% compared favorably with those of other series and supported their recommendations. Another prospective study involving patients with penetrating wounds to zones II and III looked at the efficacy of various diagnostic studies designed to evaluate esophageal injuries. Weigelt and associates”” prospectively studied 118 hemod-ynamically stable patients with penetrating neck trauma using barium swallow plus flexible and rigid esophagoscopy. Barium swallow, using biplane cineradiography, had a sensitivity of 89%, a specificity of loo%, and an accuracy of 94%. In contrast, the sensitivity of physical examination was 80% ; specificity, 64% ; and accuracy, 72%. While 5 of 8 esophageal injuries were missed with flexible endoscopy, rigid endoscopy had a sensitivity of 89%, a specificity of 95%, and an accuracy of 94%. The combination of cineradiography and rigid esophagoscopy missed no esophageal injuries. There were no false-positive results, but one false-negative result on barium swallow and one false-negative result on rigid endoscopy (not in the same patient) in this study. The authors concluded that patients with penetrating cervical trauma and no obvious clinical or radiographic evidence of arterial or esophageal injury could be safely observed. If esophagography is equivocal, rigid esophagoscopy should be performed to rule out esophageal injuly. It should be noted that although the combination of barium swallow and rigid esophagoscopy missed no injuries, these studies coupled with arteriography are time-consuming and costly. Rigid endoscopy generally requires a general anesthetic. In spite of these excellent results in identifying esophageal injury, it must be emphasized that this was a small study of only 10 patients with proven injury. Conversely, Rivers and coworkers‘ “’ identified six injuries in 61 patients evaluated by angiography. Of these 6 injuries, 3 were deemed spurious, 2 were clinically insignificant, and 1 required operative intervention. Furthermore, no significant injuries were found at arteriography in the absence of physical findings and no injuries found at operation were missed preoperatively. From these data, the authors concluded that arteriography was not necessary in the absence of physical findings and surgical explorations of patients with indications for surgery may negate the need for arteriography, thereby excluding the possibility of false-positive studies. Overall, in considering the proper management of patients with 30

Cwr

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1~2

penetrating cervical trauma, one must consider the zone of injury involved. Arteriography ma-v be indicated for patients with injuries in zones I and III. Zone I injuries may involve the arch vessels or the superior mediastinum and may require median sternotomy or anterior thoracotomy; thus, the accuracy of preoperative diagnosis is important. Similarly, because of the difficulty in exposing zone III injuries, arteriography may help plan the operative approach or the need for surgery. Management of zone II injuries, however, is more straightfonuard. Because of the relative ease of surgical exposure, many surgeons proceed directly to exploration in patients sustaining an injury in this area. However, it must be pointed out that arteriography will reliably exclude a vascular injury, as shown by the above-described studies, and if the aerodigestive can be cleared nonoperative management may be selected. In spite of impressive results with arteriography, meticulous attention must be given to several technical points. All cutaneous wounds should be marked with a radiopaque object which will help direct one’s attention to the site of injury. Whereas stab wounds generally produce a linear track, gunshot wounds are totally unpredictable. Therefore, it is essential that generous proximal and distal visualization is obtained. Wounds located low in the neck should include visualization of the aortic arch and its branches, and those patients with wounds located high in the neck require visualization of the cerebral circulation. This is especially true if there is a distal internal carotid artery injury, which may require ligation. Prior to ligation, it is important to assess the collateral circulation through the circle of Willis. A word of caution is offered regarding angiography at the thoracic outlet. It is often difficult to adequately visualize all aspects 01 this area and, hence, the study may not be as reliable as in other areas. It is difficult to rotate the patient so that all areas of these vessels are clearly seen. It is important to have the clinician present during angiography. This will allow the radiologist to have the benefit of knowing the specific areas of concern. The attending physician should review the films with the radiologist prior to the removal of the catheter. In the event the study is not satisfactory, it may be necessary to obtain additional views and different projections or even employ subtraction techniques. With the more liberal use of angiography, an increased recognition of vertebral artery injuries has been noted. For this reason, my p”tient sustaining a gunshot wound that crosses the midline should have a four-vessel study that includes both carotids and both vertebral arteries. Most patients with gunshot wounds will benefit from a four-vessel study; however, some will clearly have the injury pattern limited to one side of the neck for which an ipsilateral carotid mcl vertebral studvv will suffice. Patients with stab wounds limited to one side without contralateral involvement should have two-vessel ipsiCur-r Probl

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19’J2

31

lateral studies (carotid and vertebral). Whereas angiography has proved reliable in identifying vascular injuries, the precise type of injury may not be recognized. A report of 43 vertebral artery injuries by Reid and Weigelt” showed only a 50% accuracy in identifying the specific type of injury. The accuracy of the above-described studies of the vascular and aerodigestive systems has given more credence to nonoperative therapy. The ongoing metamorphosis toward a less invasive management mode has stimulated the use of a variety of other studies, which include duplex scans, Doppler noninvasive studies, digital subtraction angiography, digital venous angiography, and CT. Furthermore, once its role has been better defined, angioscopy may also be considered in the diagnostic armamentarium. Although routine x-rays of the neck are rarely of benefit, occasionally air may be seen in the soft tissue, or retained foreign bodies may be identified. As a minimum, x-rays should be obtained in all patients with penetrating neck injuries if no other studies are indicated. Cervical spine films are important in patients suspected of having an injury in proximity to the vertebral column. Very limited experience is available regarding noninvasive techniques for cervical trauma. Doppler flow probes can be used to detect occlusion of both the common carotid and the subclavian arteries and their respective veins. Similarly, vertebral artery patency can also be assessed. A recent study by Panetta and coworkers”’ noted improved sensitivity and specificity in a canine model using duplex scanning techniques. Using a more indirect route, Doppler flow probes. can be used to detect reversal of flow in the carotid system and may give an indication of injury therein. However, while these modalities are able to detect traumatic occlusion, experience with them is very limited in detecting traumatic intimal defects. Oculoplethysmography (OPGJ, commonly used in the assessment of nontrauma patients by measuring delays in the pulse transmitted to the eye, has not been used in the evaluation of acutely injured patients. In an attempt to preserve the detail seen with arteriography but avoid the invasiveness and potential complications of arterial punctures, intravenous digital subtraction angiography IIVDSAI was introduced. Assessing its efficacy in vascular trauma to the extremities and lower portion of the neck, Gavant and associates39 evaluated 295 patients, 11 with injuries that involved the common carotid artery. A normal appearance on IVDSA was accepted the same as a negative finding on arteriogram, whereas patients with an abno&al appearance were taken directly to the operating room without further studies. Their results showed no false-positive studies and no delayed complications secondary to false-negative interpretations. While the experience is very limited using this technique, advantages of IVDSA include no arterial puncture, rapid vessel access, and the ability to 32

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1992

use higher concentrations of contrast material to rule out an area of interest. Disadvantages include poor visualization of small vessels, difficulties in detection of subtle intimal abnormalities, and problems in differentiating vascular spasm from a subtle underl-ying injury. Moreover, many machines do not tolerate motion artifact, thereby limiting the study only to cooperative patients. Although these authors are enthusiastic about its use, one cannot recommend it for trauma patients at this time because of its inability to detect subtle injuries. With more experience and a better understanding of the natural history of minimal injury, there may be a role for its use in the future. CT has been used in evaluating injury to laryngeal structures, especially in patients sustaining blunt trauma. Penetrating injuries to the larynx are usually recognized by physical findings. Indirect laryngoscopy has been a useful modality in evaluating patients with laryngeal trauma. It is easy to detect vocrtl cord immobility, mucosal tears, endolaxyngeal hematomas, arytenoid dislocation, and luminal distortion. Soft tissue radiographs of the neck, laryngeal tomography, and contrast-enhanced laryngography have all been described, but rarely, if ever, used for evaluating penetrating trauma. Surgical exploration may be considered safer than direct laryngoscopy in a patient with possible laryngeal injury. Laryngoscopy may further aggravate an existing injury, thereby necessitating a tracheostomy.‘“’ Fiberoptic bronchscopy is another diagnostic technique more commonly used for blunt injury. Kelly and coworkers” reported their findings with 24 consecutive patients who had combined tracheoesophageal injuries. Twenty-one (88%) of the 24 injuries were penetrating in nature, and all patients had bronchoscopy performed. There was one 14% I false-negative study in the series. This patient sustained a gunshot wound to the cervical region of the trachea and died from his injuries. Because of the uncommon but real possibility that lesions can be missed, repeat hronchoscopy should be considered if indicated by the clinical situation. Examination 01 the cervical trachea, larynx, and supraglottic regions should also be reassessed. Considering all of the options available, one must ultimately make a choice as to the most appropriate treatment for each individual patient. One approach, as previously discussed, is to manage potential injuries according to the zone of injury. It is reasonable to treat penetrating injuries to zone I and zone III in an asymptomatic patient by nonoperative methods. This includes the use of arteriography, contrast studies, and endoscopic procedures as indicated to identifv potential injuries. For zone 1 injuries, arch aortography allows tsualization of the innominate, common carotid, subclavian, and vertebral arteries and is helpful in planning the appropriate SUITgical approach if an injury is identified. Patients with zone 111 injuCiu-r

Prob/

Surf,

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1992

33

TABLE Cost

2.

Calculation

Hospitalization CI MOO&y Nonoperative management Operative management Professional fee Nonoperative management Operating room 1st hour Each subsequent I/L hr

= 1 day = 2 Clays = $125.00 = S3H9.00 = s151.00

ries will benefit from the use of arteriography and visualization of the carotid artery and intracerebral circulation, which will give important information regarding the feasibility of repair and the possible consequences of ligation. Angiography may be diagnostic as well as therapeutic if embolization is a consideration. Treatment of zone II injuries may be approached in two ways. For patients with gunshot wounds, arteriography may still be of value prior to exploration in the stable patient. The extent of injury may not be clinically apparent due to the unpredictable trajectory of missiles. Stab wounds, on the other hand, are best treated by operative exploration, excluding an extensive and expensive preoperative evaluation. These patients can be explored and, if the findings are negative, discharged early from the recovery room. This approach is attractive from both a logistic and an economic standpoint. A review of esophageal injuries at Parkland Memorial Hospital”” pointed out the varying costs to the patient, depending on how extensive the workup was. The cost calculation is depicted in Table 2 and the cost of management is calculated in Table 3. If a nonoperative approach to zone II injuries is preferred, one must remember that the diagnostic accuracy of arte-

TABLE Cost

3.

of Management

Add rigid esophagugraphy (45 min of OR time1 A&l neck exploration 160 min of OK time1 Mandatory exploration lwithout diagnostic studio 160 min of OR time1

34

$3,‘t95.00 $ti,ZHO.OO $2,‘785.00

Curr

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1992

riography for penetrating trauma remains high, with a sensitivity ot 97%; however, a specificity of 90% translates into a few false-negative studies, but a false-positive rate that cannot be discounted.“’

PREOPERATIVE

PREPARATlOh

Because of the tenuous nature of potential cervical injuries, special care should be taken as the patient is prepared for surgery. This includes special precautions by the anesthesiologist as well as the surgeon. Prior to the induction of anesthesia, the surgeon and the operating room staff should be prepared for an emergency tracheostomy. Immobilization of the cervical aspect of the spine should be maintained if the integrity of the spine is still in question. In patients with a distal internal carotid artery injury, anterior dislocation of the mandible should be considered preoperatively. Most of the maneuvers prior to intubation are t&used on keeping the stimulation level to a minimum until control of the injur?/ is obtained. Intubation while the patient is awake has been described, but should be avoided if it becomes time-consuming or causes patient agitation. Rapid induction techniques may be preferable. In preparing the skin, vigorous scrubbing of the operative site is not suggested, as this may dislodge a softly formed c:lot. Therefore, surgical paint may be used in place of a formal surgical scrub, thereby minimizing the risk of dislodging a clot fixom an area of injury. Similarly, no probes should be placed into the wound. A nasogastric tube, a potential source of increasing pressure with retching and gagging during insertion, should be withheld until the risk of dislodging a clot or disrupting existing soft tissue tamponade has subsided. The nasogastric tube may be placed just after induction of anesthesia, when rapid exploration and treatment can be initiated, should bleeding occur. In addition to preparing the surgical area, if time permits, a vascular donor site should be prepared and draped if the patient has a known or potential iniury that might require an interposition graft.

Patients sustaining penetrating cervical trauma not only must be considered unique because of the anesthetic management specific to potential neck injuries, but also must be recognized in regard to precautions given any injured patient. These include: I11 immobilization of the cervical region of the spine, (2) prevention of aspiration, 131ailway control when confronted with anomalous anatomy, (41 comorbid medical conditions such as coronay artery disease and

metabolic problems, (5) abnormal pulmonary physiology, and (61 conditions that may modify pharmacologic agents often used for intubation such as sedatives and muscle relaxants. When a patient with penetrating cervical trauma is intubated, oral intubation using manual in-line axial support is preferred unless the certainty of cervical spine integrity has been ensured. A modified rapid sequence induction is generally used.42 This entails ventilation by mask followed by cricoid pressure while the intubation is performed. Surgical control of the airway is rarely indicated, but during intubation the surgeon needs to be standing by in case difficulty is encountered. The more common techniques of intubation include rapid control intubation, awake intubation, or fiberoptic intubation. With rapid control intubation, the patient is preoxygenated with 100% oxygen while awake. d-Tubocurarine (DTC1 is given intravenously 2 to 3 minutes prior to intubation. This pretreatment is crucial when using succinylcholine, which induces muscle spasm of the abdominal wall and may increase intragastric pressure, thereby causing possible regurgitation with subsequent aspiration. This sequence of events can be prevented if the patient is blocked with DTC. After the injection of DTC, cricoid pressure is applied, followed by induction with either thiopental or ketamine, depending on the patient’s cardiovascular status. Thiopental is generally avoided in hypovolemic patients. Next, succinylcholine is given, followed by immediate intubation. It is important that during the preoxygenation period and prior to intubation, no positive pressure ventilation is given via the mask. This will further lessen the risk of inflation of the stomach with subsequent regurgitation. Awake intubation is used more frequently in patients with airway and cervical injuries. The advantage of this technique is that the patient voluntarily controls his or her own airway and thereby has the benefit of maintaining the protective reflexes intact. Prior to intubation, the patient is anesthetized topically using lidocaine followed by some form of sedation. The patient must be fairly coooperative in order to use this technique, which limits its application in the trauma population. Awake intubation can be accomplished using either the oral or the nasal route. However, for cervical trauma, direct visualization using an oral route is preferable. This technique should not be used in a combative or restless patient, as a doctor-patient struggle produces a potentially dangerous situation. Fiberoptic intubation is helpful when previous attempts at intubation have failed. The technique is somewhat limited because it is not rapid and it requires a significant amount of topical anesthesia. The fiberoptic laryngoscope, after being lubricated, is slipped into an appropriate-sized endotracheal tube. The scope is passed through the tube, past the epiglottis, and into the glottis. It is advanced past the 36

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1992

vocal cords and into the trachea, at which time the endotracheal tube is advanced over the scope to secure intubation. When this technique is used, transillumination of the larynx and trachea is helpful in guiding the scope and tube. Although the light is visible as the tip of the scope passes the glottis, it may also be seen if the scope is inserted into the esophagus.

SURGICAL SURGICAL

EXPOSURE, TECHNIQUE, MANAGEMENT

AND INITIAL

A variety of incisions are used to provide surgical exposure in patients with penetrating neck trauma. Selection is determined by the zone of potential or known injmy. An incision along the anterior border of the sternocleidomastoid muscle gives good exposure for zone II and III injuries. Proximal and distal control is obtained prior to approaching the area of injury. The technique of obtaining proximal and distal control is similar to that used in peripheral vascular trauma. The actual site of injury is initially avoided, as vessel loops are placed proximal and distal to the area involved. Gentle digital pressure is applied, if necessary, to control bleeding while the patient is stabilized prior to attempting further dissection. Exposure and control of the distal internal carotid artery may be difficult. Both temporary and permanent control may be obtained by using a Fogarty balloon catheter with a detachable balloon. As described earlier, visualization of the vertebral artery can also be accomplished by using this incision. Additional exposure of the carotid artery high in the neck can be obtained by anterior subluxation of the mandible. Using a circummandibular/transnasal wiring technique, the mandible is pulled inferiorly and anteriorly.“” This technique is rapid and simple to perform and is not associated with any postoperative temporomandibular joint dysfunction. Two other procedures may facilitate visualization of the distal internal carotid artery: 111 detachment of the sternocleidomastoid muscle from the mastoid process, and (21 division of the digastric muscles and occipital artery. Exposure of injuries located at the base of the neck involves a number of options (see Fig 7i. If the patient is hemodynamically stable, an incision along the medial aspect of the clavicle will give access to the right proximal subclavian artery and both subclavian veins. This can be accomplished either with or without a subperiosteal resection of the medial one third of the clavicle. If the patient is hemodynamically unstable, a median stemotomy is preferable as a faster and safer means of obtaining control of the vessels of the thoracic inlet. From this exposure, the incision can be extended into the left or right side of the nmk An anterolateral thoracotomy in the

third intercostal space allows rapid vascular contol for patients with significant ongoing hemorrhage. With this exposure, manual compression in the apex of the thoracic cavity can be applied to obtain hemostasis. This maneuver may be followed by a medially placed vertical incision connecting the previously placed clavicular incision, forming a segment of anterior chest wall that can be retracted outward as a hinge or “book.” This later technique is rarely used.44 A left anterior thoracotomy in the third or fourth intercostal space is the incision of choice for injuries to the proximal left subclavian artery. Once control is obtained, one must consider the use of anticoagulation, the use of intraluminal shunts, the neurologic status of the patient, and the proposed technique of repair. Systemic anticoagulation is usually not required for simple repair of a laceration or partial transection injury. However, if there are no contraindications to the use of heparin, such as associated abdominal, osseous, or cerebral injuries or if a prolonged clamp time is anticipated because of a complex repair, full heparinization should be given prior to clamping the vessel. Reversal of heparin by using protamine at the termination of the repair is optional. Most of the time, the half-life of heparin has been exceeded and reversal is not necessary. If protamine is used, it should be infused slowly to avoid the transient hypotension occasionally seen with its use. Contrary to elective carotid vascular procedures, shunts are infrequently used in common carotid artery injuries, especially if the distal clamp is applied proximal to the bifurcation of the internal and external carotid arteries. The decision to use a shunt is based on the length of proposed clamp time, the neurologic status of the patient, the knowledge of collateral circulation, the pressure and flow characteristics of bleeding when the distal clamp is temporarily removed, and the personal choice of the surgeon. Shunts are generally used if the clamp time is prolonged, the stump pressure is less than 50 mm Hg, or an interposition graft is warranted. Although the surgeon should be familiar with the various types of intraluminal shunts, it must be emphasized that the placement of these devices is not without potential complications, such as tearing or embolization of plaques, or inadvertent intimal dissection. Heparinization is necessary if a shunt is used; hence, this is an important consideration especially if the use of heparin is contraindicated. As with most vascular injury repairs, arteriography should be performed at completion to ensure a patent and adequate anastomosjs as well as a clean distal conduit. This is essential in the carotid artery because of the devastating sequelae of either thrombosis or embolization. Vascular injury in the neck differs from peripheral vascular trauma in terms of the end-organ response. Patients with a vascular injury may or may not have a neurologic deficit. The decision to repair a cervical vascular injury is influenced, therefore, by the severity and 38

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duration of neurologic impairment, if such exists. The literature is somewhat controversial regarding vascular repair if the patient has a dense neurologic deficit. The concerns are twofold. First, there is the potential problem of converling an ischemic infarct to a hemorrhagic one with revascularization. Second, it is uncertain to what extent reduction of flow or distal embolization contributes to cerebral ischemia and infarction after carotid artery injury. A variety of factors combine to determine the degree of ischemia or adequacy of cerebral blood flow after carotid injury; these include the degree and site of flow reduction, existence of collateral channels, cardiac output, and efficiency of the cerebral vascular compensatory response to flow reduction in the injured vessel. HLypotension may exaggerate cerebral ischemia, but does not appear to have a predictable deleterious effect on the eventual neurologic status.“” Whereas there has been a reluctance in the past to repair vessels and reestablish flow if a moderate or dense neurologic deficit was present, most authors now advocate repair regardless of neurologic status. If the neurologic function of the patient is normal preoperatively, repair of the injured vessel is advocated. Even extensive wounds resulting from high-velocity missiles can be repaired using standard vascular techniques, such as b-ypass and interposition grafts. An exception to this may be when there is complete obstruction of the flow at the site of injuly with intraluminal thrombosis in the cephalad portion of the vessel. The concern with revascularization in this situation would be one of distal embolization.l“ The mortality rate after vascular reconstruction of penetrating carotid artery injuries without a preoperative neurologic deficit is less than 4%. Moreover, postoperati\re ischemic deficits occur in less than 2% of patients.“” In contrast, the results 01‘ reconstructive surgery in patients with preoperative neurologic deficits are not as satisfactory. In a review by Bradley,‘” a high mortality rate was associated with patients who had preoperative neurologic compromise. Of the 24 patients studied with carotid injuries, all of the 14 patients without preoperative neurologic deficits survived repair. Conversely, 5 of the 10 patients with preoperative neurologic deficits did not survive. Bradley compared the similarity between acute arterial obstruction due to trauma and that of atherosclerosis, thereby recommending ligation of the carotid artery in patients with severe preoperative deficits. Similar findings were reported in a review of 60 patients with carotid artery injuries from Parkland Memorial Hospital.‘7 This study investigated the importance of the severeity of the neurologic deficit with respect to the restoration of blood flow. Patients were classified into three neurologic groups: 111 those with mild deficits and prograde carotid flow, 12) those with severe preoperative deficits with prograde flow, and 131 those \\-ith severe preoperative defic:its withCur-r

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39

out prograde carotid flow. Prograde flow was present in 5 of 6 patients with mild deficits, all of which were successfully repaired without neurologic sequelae. Prograde flow was also noted in 10 of 13 patients with severe neurologic insults. Nine of these patients were repaired and one was ligated. Five of these patients recovered with either complete or partial improvement in their neurologic status. Two patients had no improvement and 2 patients died. Of the 3 patients with a severe preoperative deficit and no prograde flow, ligation of the vessel was performed and resulted in improvement in 1 patient, no change in 1 patient, and death of the remaining patient. The authors concluded that vascular reconstruction should be performed in patients, regardless of neurologic status in the presence of prograde carotid flow. Conversely, ligation was recommended for those with a severe neurologic deficit and no prograde carotid flow. They also recommended that for patients with a neurologic deficit, prograde flow, and a distal thrombus that cannot be retrieved, ligation is the treatment of choice. Other authors have advocated vascular repair rather than ligation for all penetrating carotid trauma. Leikweg and Greenfield4” reviewed 233 cases, finding no greater morbidity or mortality in patients regardless of neurologic deficit, with the exception of coma, who had a primary repair as compared to those who were ligated. Similarly, Ledgerwood and colleagues4” reported their experience with 36 patients with carotid artery injury, the majority of which had penetrating trauma. They also found that the preoperative neurologic status of the patient directly correlated with postoperative function. Moreover, the patients in their series who were in shock or had absent arterial flow were also at higher risk of postoperative stroke. These authors recommended carotid artery repair for all patients who were not comatose, had stable vital signs, and had technically repairable injuries. Unger and associates’” reviewed 186 patients with a severe neurologic deficit after penetrating carotid artery trauma. They found that the patients with arterial repair fared better than those with ligation, noting a 34% improvement in those repaired and only a 14% improvement with either ligation or observation. While shock or coma were independent indicators of poor outcome there was no evidence to support coma as a contraindication to restoring arterial continuity. There is still no consensus regarding the best treatment of patients presenting with coma as evidenced by the plethora of articles reviewing this problem. Brown and coworkers”’ compared the results of revascularization and ligation in 129 patients with carotid artery injuries. While surgical repair was clearly the preferred operative choice in patients with neurologic deficits short of coma, they concluded that revascularization may also be considered in patients 40

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with preoperative coma of short duration. This conclusion was based in part from the results of their review and in part by autopsy studies reported by Ledgerwood and colleagues4B who found that death in patients revascularized with preoperative coma was related to cerebral edema and not to hemorrhagic infarction. Brown and coworker$l recommended, therefore, that if one can minimize cerebral edema and infarction size, as well as limit ischemic time prior to surgery, revascularization offered the best chance for survival and acceptable recovery. Richardson and associates,52 stud”ying 33 patients with penetrating cervical injuries, also found no significant advantage of ligation over repair in 8 patients with severe preoperative neurologic deficits. They concluded that aggressive revascularization may lead to equal or superior results than would ligation alone. One of the more recent contributions to this controversial subject is reported by Weaver and associates.“” They reviewed PO patients with penetrating extracranial carotid injuries with varying degrees of neurologic deficit. Patients were subsequently categorized by their mode of treatment. They quantified the neurologic outcome and concluded that arterial reconstruction was the management of choice in patients with penetrating carotid artery trauma. These authors agreed with Ledgerwood’s h.ypothesis that the presence of a neurologic deficit and concern over conversion of an ischemic infarct to a hemorrhagic infarct should not alter the approach. Weaver and associates introduced another area of controversy by stating that patients with minimal injury may be managed expectantly with serial arteriography, much as is becoming the trend in peripheral vascular trauma. A word of caution must be introduced. The natural history of nonoperative treatment of vascular injuries is as yet undetermined. Whereas initial reports are encouraging, the risk of thrombosis or embolization into the head does not warrant recommending this form of management, especially for cervical vascular injuries, until more data are available. Most authors now agree that the restoration of cerebral vascular flow should be performed in all patients with carotid occlusion, with the possible exception of those with profound neurologic deficit, although even this recommendation has been challenged. In performing revascularization, consideration should also be given to the risk of embolization in patients with intraluminal thrombosis that can be safely retrieved.44 In those f&w patients, ligation may be the treatment of choice. If one contemplates operating on a patient with a vertebral artery injury, the patient should be placed on the operating table in a supine position. The patient’s head is turned away from the operative site, the neck extended, and a roll placed under the shoulders. The incision divides the skin, plat,vsma, and fascia along the anterior borCurr

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41

der of the sternocleidomastoid muscle from the cricoid to the mastoid process. Among the important landmarks are the sternocleidomastoid muscle, the spinal accessory nerve, the prevertebral fascia, the levator scapulae muscle, and the splenius capitis muscle. The spinal accessory nerve enters the muscle 3 to 4 cm below the tip of the mastoid process and care must be taken during the dissection to avoid its injury. The sternocleidomastoid muscle is divided at the insertion with the mastoid process. This is followed by mobilization of the sternocleidomastoid muscle, which is retracted laterally and inferiorly. At this point, it is prudent to identify the spinal accessory nerve, by opening the prevertebral fascia, before exposing the levator scapulae from the transverse process of the atlas. The thin first tendon of the splenius cervicis is divided allowing exposure of the third portion of the vertebral artery. To expose the vertebral artery in the C2-6 region, bone rongeurs can be used to remove the anterior cortical portion of the transverse processes. The anterior ramus of the cervical nerves lies directly behind each of these arterial segments. This ramus curves sharply forward around the artery such that nerve injury may occur if the anterior tubercle of the transverse process is removed. Also, care must be taken to prevent injury to the suboccipital venous plexus present around the vertebral artery in the region of the atlas. Moreover, meticulous dissection must be performed to protect the vertebral vein, which accompanies the vertebral artery being fed from each cervical vertebra. The thoracic duct is rarely but occasionally injured and it may be difficult to identify. Anatomically, it passes along the right side of the tracheoesophageal groove, crosses over to the left side behind the aortic arch, and continues to pass along the left margin of the esophagus to the level of the transverse process of Ci’. At this point, it bends laterally and behind the carotid sheath, passing in front of the left vertebral artery. As it approaches the medial border of the anterior scalene muscle, the thoracic duct travels inferiorly in front of the phrenic nerve and the first part of the subclavian artery and drains into the proximal left innominate vein, the distal left subclavian vein, or the internal jugular vein. Missed injuries to this structure may ultimately be recognized as a persistent neck fistula, or a chylothorax if it communicates with the chest. It is unusual for a patient to leak a large amount of lbymphatic fluid at the time of the initial operation; hence, the injury can be easily overlooked. If the injury is recognized, the 1~ymphatic leak can be identified, and easily controlled. On the right side, a thoracic duct is present and receives lymph drainage from the right side of the head and neck, right arm, right side of the chest, and both lungs. It drains into the right jugulosubclavian angle as either a single channel or tributaries that may end independently. 42

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MANAGEMENT

OF SPECIFIC

ORGAN

INJURIES

Once the decision regarding appropriate management has been made, whether this be selectilre observation or mandatol-y exploration, attention is turned to the treatment of specific injuries. The surgical approach to penetrating neck injuries is illustrated in Figure 7 and has been pre\iousiy described.

Surgical control of the airway has been considered elsewhere. If tracheostomy is indicated, it is preferably performed in the operating room, if time permits. indications include severe maxillofacial trauma, selected laryngeal and tracheal injuries, and situations where cricoth-yroidotomy cannot be performed. Placement of the tracheostomy appliance should be at least one ring below the injury, if it is located in the larynx or upper trachea, while in the lower cervical portion of the trachea, the site of the injury itself may be the best place to secure the airwa),. Tracheal and laryngeal injuries should be repaired with a single laver of absorbable suture. /\vulsed cartilage should be adequately dkbrided prior to closure. In cases of mucosal penetration, the mucosal layer may be closed with an absorbable suture followed by approximation of the tracheal or laryngeal cartilage. Primary mucosato-mucosa closure of any respiratory tract defect is essential. The use of permanent monofilament suture is another option when closing the cartilaginous support structures. In cases of extensive tracheal defects, a suprahyoid tissue release may be required. Furthermore, a musculofascial flap, skin graft, or local mucosal advancement flap may accommodate wound closure. In patients with significant disruption of the cartilaginous support of the larynx combined with extensive soft tissue injury, stenting may be reqr Reid and Weigelt,“’ ther,f, is ;I risk of’ inaclequate or inaf)f)l‘“l”‘iat’! therapy in these patients. Cervical venous injuries arc’ evaluated on an individual basis. As a general rule, venous injuries (‘ause t’ar~ feww problems than their a~‘terial counterparts. Injuries to the internal jugular vein should t)c repaired whenever l’easible. ~\c~c:eptable techniques include lateral vf:~Iorrhaphy, resection and f)rimaqv anastomosis, and on rarer occasions, patch venoplast>,. In cases where an interposition vein graft would be necessary, ligation is preferrect unless the patient has obstruction of the co~ltI~alatel~~~1internal jugular vein. I!’ this OCCLII~S, a greater effort should br made to repair the venous injul??. iMiIlO1 veins of the neck can be ligatc~d without difficultv. ‘I’he most serious potential complication assfv:i;Iteci mith repair of: an internal juglIar. Curr

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vein is air embolism. This is less of a problem when positive pressure ventilation is maintained. Local exploration in the emergency room should never be performed if a vascular injury is even remotely possible. THOKACIC

DUCT

INJURIES

Injury to the thoracic duct is uncommon, but should be considered during exploration of any injury in proximity to the internal jugular vein-subclavian vein junction on the left side. Failure to identify a major 1~ymphatic injury, which may not be obvious at exploration, may result in formation of a lymph fistula with subsequent lymphocele or chylothorax. If an injury to the thoracic duct is identified, the duct should be ligated rather than repaired. CERVICAL

NERVE

INJURIES

A thorough familiarity with the neuroanatomy is essential for the detection of injuries associated tith penetrating neck trauma. Injury to the vagus, phrenic, recurrent laryngeal, hypoglossal, spinal accessory, and brachial plexus nerves must be considered. Although primary repair of these injuries is rarely successful, the principles of nerve repair should be practiced, namely, adequate dkbridement and primary anastomosis with fine interrupted sutures placed in the perineurium. Optical magnification will facilitate alignment and reapproximation of these delicate structures. Occasionally, interposition grafts may be indicated. In an acute setting, however, it may be more prudent to tag the ends and delay repair until a more opportune time. This is especially true if the wound is contaminated or the patient is unstable. GLANDULAR

INJLJHIES

The thyroid gland with its rich vascular supply has the potential for significant bleeding when injured. However, thyroid injuries are uncommon and the sites of bleeding are easily controlled with suture ligatures. Extensive injuries may necessitate thyroid lobectomy. In such cases, care must be taken to identi& and follow the path of the recurrent laryngeal nerve to prevent injury. Parathyroid glands, because of their size and location, *are rarely injured. They should be identified and protected if at all possible. They may be encountered during dkbridement of an extensive thyroid injury, but are often obscured because of excessive bleeding. When identified, they should be tagged with a suture for identifica50

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tion in case subsequent surgery is necessay. If devascularized, autotransplantation should be strongly considered. Salivary gland injuries, also rarely see11 are treated by hemostasis, dkbridement, and closed suction drainage. While the tail of the parotid gland is at risk for injuly with high neck trauma, the more commonly injured structures during its exploration include Stonsen’s duct and the facial mne. ‘I’he submandibular gland is enveloped in the superficial layer of the deep cervical fascia and, when injured, may be excised. M’arton’s duct must be stsxrely ligated. ‘l-he anatomy of the marginal mal~dibular branch of the facial nerve is also important to recognize : a11d I)rotect whm this area is dC?bridod.

Following the surgical principles of wound care, all necrotic IIILIScle and soft tissue should b(? avid+ d&rided. Depending on the extent of the dkbridement, it may he necessary to close the defect with a split-thickness skin graft or a myocutaneous flap. Soft tissue coverage of all exposed vessels is essential prior to wound closure. ‘This cm be accomplished by intt:rl)osing a n~usclt~ flap such as the levator scapulae muscle.

INFECTIOUS

COMPLICATIONS

Although controversial, intravenous antibiotics are generally recommended for patients sustaining penetrating trauma to the neck. While the incidence of infection is low in patients with an isolated vascular injury, the potential of injury to the aerodigestive system makes the use of a routine preoperative dose a reasonable consideration. Penicillin is still an excellent choice for these injuries, although a first-generation cephalosporin, while much more expensive, also gives acceptable coverage. In general, cervical infections do not occur acutely, but rather several days after injuly. One should consider missed injuries to the respiratory or gastrointestinal tracts when soft tissue or fascial infections develop. Spinal fluid contamination may be another source. Cervical osteomyelitis is 0c:casionally seen following gunshot wounds, especially if the missile has traversed the gastrointestinal tract en route to an osseous destination. Although abscesses are general1.v confined to fascial planes, on a rare occasion they ma-y erode into normal or repair-td \rascular structures causing major hemorrhage. Heiden and coworkers”) reviewed the cases of 38 civilians with gunshot wounds to the c1~11ical spine. None of the 16 patients

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treated nonoperatively developed infectious complications. However, in the operative group 1 patient developed a spinal fluid infection and 1 developed a superficial wound infection. They noted a lower incidence of infections following low-velocity-missile injuries as compared to the injuries produced by higher-velocity, fragmenting missiles typical of military issue. Jones and coauthors71 reported on four patients with cervical osteomyelitis following transpharyngeal gunshot wounds. They found that delayed operative intervention as well as inadequate debridement of devitalized soft tissue and bone were common features in these patients. These authors concluded that thorough debridement of soft tissue and bone, adequate drainage, broad-spectrum antibiotics, and rigid immobilization of the cervical spine were crucial elements in the care of these patients.

CONCLUSIONS

Although, at times, patients are seen with innocuous-appearing wounds, one must maintain a healthy respect for the potential injury that can occur in any of the numerous anatomic structures found in the neck. A keen awareness of the mechanism of injury, taking into consideration the unpredictable trajectory of missile injuries, will minimize the incidence of missed injuries and the inevitable increase in morbidity and mortality. The natural history of some of these subtle injuries is such that complications may not manifest for several hours, days, or in the case of some vascular injuries, even months and years. The diagnostic evaluation begins with the complete history including facts surrounding the prehospital period followed by a thorough physical examination. Depending on the physical findings in a patient with the hemodynamic, ventilatory, and neurologic stability, a variety of other diagnostic studies may be obtained. Subsequent to the clinical evaluation, a management decision will have to be made regarding either operative or nonoperative therapy. Controversy still exists regarding the optimal manner in which the asymptomatic patient should be treated. Hospital observation without an extensive diagnostic workup has been advocated by several large centers. Mandatory operative exploration is still favored by a small number of authors, whereas others would recommend any number of diagnostic procedures before selecting one form of management over another. These authors would suggest that patients with injuries in zones I and III would benefit from angiography to either help plan the operation if an injury is identified, or safely manage the patient nonoperatively if other injuries are not a consideration. Furthermore, those 52

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patients with injuries in zone II may be best managed by taking them directly to the operating room, followed by early discharge without hospitalization if no injury is found and there is no other reason for hospital care. Although vascular injuries are potentially life-threatening, one must be aware of possible injury to each and every anatomic structure located in the neck. Special considerations are given to the perioperative care as well as the various operative procedures. As newer diagnostic techniques become available and operative technology continues to improve, the management strategy is bound to evolve. Until such time, however, one can expect very low and acceptable morbidity and mortality rates by following sound general surgical principles and recognizing the potential dangers associated with penetrating neck trauma. REFERENCES 1. Watson WL Silverstone SM: Ligature of the common carotid artery in cancer of the head and neck. Ann Surg 1939; 109:l. 2. Fleming D: Case of rupture of the carotid artery; the wounds of several of its branches, successfully treated by tying the common trunk of the carotid itself. Med Circ J 1817; 32. 3. Makins GH: Gunshot Ir@ries to the Blood Vessels. Bristol, England, John Wright and Sons, Ltd, 1919. 4. Lawrence KB, Shefts LM, McDaniel JR: Wounds of the common carotid arteries, report of seventeen cases from World War II. Am J Surg 1948; 7ti:ZS 5. Hughes EW: Arterial repair during the Korean War. Ann Surg 1958; 147:555. 6. Rich NM: Vascular treatment in Viet Nam. J Cardiovasc Surg 1970; 11:368. 7. Golueke PJ, Goldstein AS, Sclafani SJA, et al: Routine versus selective exploration of penetrating neck injuries. A randomized prospective study. J Trauma 1984; 24:lOlO. 8. Campbell FC, Robbs, JV: Penetrating injuries of the neck: A prospective study of 108 patients. Br J Surg 1980; 67:582. 9. Saletta JD, Lowe RJ, Lim 1,‘l‘. et al: Penetrating trauma of the neck. J Trauma 1976; 16:579. 10. Reid JDS, Weigelt JA: Fortythree cases of vertebral artery trauma. .I Trauma 1988; 28:1007. 11. Merion RM, Harness JK, Ramsburgh SR, et al: Selective management of penetrating neck trauma. Arch Surg 1981; 116:691. 12. Narrod JA, Moore IX: Selecli\,e management of penetrating neck injuries. Arch Surg 1984; 119:574. 13. Bishara RA, Pasch AR, Douglas DD, et al: The necessity of mandatory exploration of penetrating zone II neck injuries. Surgery 1986; 100:65.5. 14. West JG, Trunkey DD, Lim RC: Systems of trauma care: A study of two COUIIties. Arch Surg 1979; 114:4.55. 15. Snell RS: The head and neck, in Snell RS leci): Clinical Anatomv,fiw Medical Students, ed 2. Boston, Little, Brown, 1981, pp 603-605. 16. Barach E, Tomlanovich M, Nowak R: Ballistics: A pathophysiologic examination of the wounding mechanisms of firearms. Part I. .I Trauma 1986; 26322.5. 17. Ordog GJ, Wasserberger J, Balasuhramaniam S: Shotgun wound ballistics. J Trauma 1988; 28:624. Curr Probl Surg, Januq

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18. Ordog GJ, Wasserberger J, Prakash A, et al: Civilian gunshot wounds: Determinants of injury. J Trauma 1987; 27:943. 19. Fackler ML: Wound ballistics: A review of common misconceptions. JAMA 1988; 259:2730. 20. Tadula RT, Sandler SC, Camishion RD: Delayed bullet embolization to the heart following abdominal gunshot wound. Ann Surg 1969; 163:533. 21. Abdo F, Massad M, Slim M, et al: Wandering intravascular missiles: Report of five cases from the Lebanon war. Surgery 1388; 103:376. 22. Mattox KL, Beall AC, Ennix Cl,, et al: Intravascular migratory bullets. Am J Surg 1973; 137:192. 23. Adams VI, Hirsch CS: Venous air embolism from head and neck wounds. Arch Path01 Lab Med 1389; 113:438. 24. McCormick TM, Burch BH: Routine angiographic evaluation of neck and extremity injuries. J Trauma 1979; 13:384. 25. Fogelman MJ, Stewart RD: Penetrating wounds of the neck. Am J Surg 1956; 31:581. 26. Sheely CH 11, Mattox KL, Reul GJ Jr, et al: Current concepts in the management of penetrating neck trauma. J Trauma 1975; 15:895. 27. Snyder WH III, Thal ER, Bridges RA, et al: The validity of normal arteriography in penetrating trauma. Arch Surg 1978; 113:324. 28. Carducci B, Lowe RA, Dalsey W: Penetrating neck trauma: Consensus and controversies. Ann Emerg Med 1986; 15:208. 29. Flint LM, Snyder WH, Perry MO, et al: Management of major vascular injuries in the base of the neck: An llyear experience with 146 cases. Arch Surg 1973; 106:407. 30. Hiatt JR, Busuttil RW, Wilson SE: Impact of routine arteriography on management of penetrating neck injuries. J Vast Surg 1984; 1:860. 31. Jurkovich GJ, Zingarelli W, Wallace J et al: Penetrating neck trauma: Diagnostic studies in the asymptomatic patient. J Trauma 1985; 25:SlS. 32. Ayuyao AM, Kaledzi YL, Parsa MH, et al: Penetrating neck wounds. Mandatory versus selective exploration. Ann Surg 1385; 202:563. 33. Ordog GJ, Albin D, Wasserberger J, et al: 110 bullet wounds to the neck. J ‘Dauma

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25:238.

34. Noyes LD, McSwain NE Jr, Markowitz IP: Panendoscopy with arteriography versus mandatory exploration of penetrating wounds of the neck. Ann Surg 1386; 204:Zl. 35. Meyer JP, Barrett JA, Schuler JJ, et al: Mandatory vs selective exploration for penetrating neck trauma. Arch Surg 1387; 122:532. 36. Weigelt JA, Thal ER, Snyder WH 111, et al: Diagnosis of penetrating cervical esophageal injuries. Am J Surg 1987; 154:619. 37. Rivers SP, Pate1 Y, Delany HM: Limited role of artcriography in penetrating neck trauma. J Vast Surg 1988; 8:112. 38. Panetta T, Hunt JP, Buechter KJ, et al: A blind, randomized canine study of duplex scanning and arteriography for the diagnosis of arterial injury. J Trauma 1930; 30:927. 33. Gavant ML, Gold RE, Fabian TC, et al: Vascular trauma to the extremities and lower neck: Initial assessment with intravenous digital subtraction angiography. Radiology 1986; 158:755. 40. Stanley RB Jr: Value of computed tomography in management of acute laryngeal injury. J Trauma 1984; 24:359. 41. Kelly JP, Webb WR, Moulder PV, et al: Management of airway trauma II: Combined injuries of the trachea and esophagus. Ann Thorac Surg 1987; 43:160. 54

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42. 43. 44.

45.

46. 47.

48.

Grande CM, Stene JK, Bernhard WN: Airwav management: Considerations in the trauma patient. Crir Care Cfin lY90; ti:37. Fisher DP, Clagett GP, Parker Jl. et al: Mandibular subluxation f’or high (:arotid cxposure.J Vast Surg 1984; l:T27. Snyder WH III, Thai EK: Peripheral and Abdominal Vasc;ular Injuries in Kutherford KB led): Vascuhr Sur:;ery, ed 2. Philadelphia, b%‘B Saunders (:ornpay, 1984, pp 473-474. Kassell NE‘, Boarini DJ, Adams HP Jr: Intracranial and Cervical Vascular Injuries, in Cooper PR Icxll: tIf:;rd Injuryv, f:d 2. Raltimore, Williams &. \l’ilkins, 1987, pp 327-354. Bradley EL III: Management of penetrating carotid injuries: /\I> allerl~ati\~e approach. .I Trauma 19X; 13248. ‘l‘hal ER, Snyder M’H, lfqws K, f’t al: ~2anagt:n~ent of c,arotici artq’ injuric:s. Surge7-y 1974; 76:955. Leikweg WC; Jr Greenlield 1.J: \Ianagomc:nt of penetrating carotid arterial iiiJuly.

49. 50.

Ann

1980;

51. 52. 53. 54. 55.

1978;

Surg

188:58T

Ledgerwood ,\bl, Mullins KI, I.uras (2:: Primary repair vs ligatiolr for artery injuries. r\l-ch Surg 1980. 115:48X. linger SLY. Tricker \1’S .Jr hlrd~:~a hl;\, cat al: (:arotirl arterial Iraunla.

carotid .Siqf:rv

S’i:4;7.

Brown MF, Graham JM Ft:lic.iatlo III’, c’t al: (:arotid artery injuries. ,.\771 .I .Sur-g lY82; 144748. FK: Management of c:arotid artniy trauma. Kichardson JD, Simpson C‘. \liller Surcge7y 1988; 104:673 Weaver FA, Ycliin AE,, Wag~wr l\‘H, et al: ‘l’he role of’ arterial lecoilstr,Llctioli in penetrating carotid injuries Arch Surg 1988; 12:3:1106. Flatterer MS Jr, ‘I‘OOII KS, b:llt:stad C. et al: Management of blunt and pc:~w trating external esophageal Irarrnia. .I ‘I?-awna lY85; 25:784. Llrschel HC Jr Kazzuk .11/I, l\‘oc)d KE, et al: Improved managenit:nt of esophageal pfx~oration: b:sc~lusioil and diversion in c-0ntinuit.v. AIIII Surg 1974: lSY:58$.

56.

Winter

57.

Koyd

AD,

Surs

Nounds

58.

5~.

KK, Weigelt Conian

J;\: (:el\ic:al .A.\:

esophageal

tCmc~rgc~nc;y

trauma.

c,l.ic:oth~roidotorll,v:

1990: 125:849. LISC: justified?

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Golueke

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1923. of Surgfo~is, Sut)c~oinIrlitte~: on i\dvanced Trauma Support: Airway nianagerilellt and ventilation, in Advanced Traurna I,$ purr Manual. Chicago. II: American College of Surgeons, 1988, p 31.

American

Feliciano DV, Kitondo (X, Mattox KI,. et al: Combined juries. itrn .I Surg 198.5: 15U:ilO Fly RE, Fry WJ: Extracranial carotid arter?/ injuries. Meier DE, Brink XD, Fry LVJ: Vc~rtchral artery trauma.

64.

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P, Sclafani

S, Philli[ls

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Life Sup-

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Surgery 1980; X8:581. Arch Surg 19X1; Il623ti. artery irijLiIV--(li;iall(~sis and

.I ‘7‘raurrla 1987; 27:S.W KL, LVea\w b’;I, Y~~ilin AE, et ai: ‘I’rends in the n~a~~agc:n~r:~it of traumatic vertebral artciy iniufies. ArrI .I Surg 1989: 15X:101. Ben-Menachem Y, Fields L\‘S. (:ada\id G c:t al: \‘ertebral arlely tra~~ma: ‘I‘ra~lsc:atheter emholization. ,,Uz\il< l!lX7: X:501. btjer HH, Rirciy PI), Ncinun M, f:t al: Subtcniporal transdural LI~C 0C tlctac:hahlt: balloons tar Iraun~iiti~~ c~~ir.otid-c:avt:riloLis fistulas. Nf,flr-osurg~7v 1988; 22:290. Sakamoto ?‘, Yagi K, Hiraide A. et al: ‘l‘ranscatheter trrnbolization in the treatment of massivr bleeding (1111: to maxillofacial injuly. .I Trwfrna 1988; 28:

x40 Cur-r Probl

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January

19%

55

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Curr

Probl

Surg,

January 1992

Penetrating neck trauma.

PENETRATING NECK TISAUMA INBRIEF Penetrating neck trauma involves a small fraction of a surgeon’s overall clinical experience. However, the extent...
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