Emerg Radiol DOI 10.1007/s10140-015-1299-4
CASE REPORT
Core curriculum illustration: scapulothoracic disassociation Nupur Verma & Ken F. Linnau
Received: 23 January 2015 / Accepted: 3 February 2015 # American Society of Emergency Radiology 2015
Abstract This is the 14th installment of a series that will highlight one case per publication issue from the bank of cases available online as part of the American Society of Emergency Radiology (ASER) educational resources. Our goal is to generate more interest in and use of our online materials. To view more cases online, please visit the ASER Core Curriculum and Recommendations for Study online at: http://www. aseronline.org/curriculum/toc.htm.
ally displaced right scapula relative to the thoracic cage, widening at the right sternoclavicular joint (Fig. 2a), and complete transection of the right axillary artery (Fig. 2b) for which the patient undergoes operative repair. Subsequent magnetic resonance (MR) imaging performed approximately 1 month later shows diffuse high signal in the brachial plexus (Fig. 3).
Keywords Scapulothoracic disassociation . Upper extremity . Computed tomography angiography . Brachial plexus
Discussion
History A 48-year-old man fell 200 ft during an avalanche while skiing and suffered prolonged extrication. He has a cold pulseless right arm, with loss of sensory and motor function, and is airlifted to the trauma center.
Findings On physical exam, the patient has decreased pulses in the cool and ischemic appearing right upper extremity. Chest radiograph, performed as part of primary trauma survey, shows the right scapula laterally displaced from midline when compared to the left (Fig. 1). Subsequent computer tomographic (CT) angiogram shows posteriorly and laterN. Verma (*) : K. F. Linnau Department of Radiology, University of Washington, 325 Ninth Ave, Box 359728, Seattle, WA 98104, USA e-mail: [email protected]
Scapulothoracic disassociation represents a closed forequarter amputation secondary to severe lateral traction on the upper extremity, most commonly from motorcycle accidents [1]. The injury is characterized by fractures or dislocations separating the upper extremity from the thoracic cage, with swelling and deformity of the chest and proximal upper extremity from underlying soft tissue sheering, edema, and hemorrhage. The patient may present with decreased to absent sensation, reflexes, and distal pulses [1, 2]. As scapulothoracic disassociation is a marker of high-energy trauma; it raises the patient’s likelihood of having other concomitant major injuries, including other orthopedic and central neurological injuries [1]. Recognizing the displacement of the involved extremity’s scapula asymmetrically laterally relative to the midline is often the initial clue on chest radiography. Extensive separation at a clavicle fracture, acromioclavicular separation, or sternoclavicular dislocation may also be seen. Additional findings on radiography may include an apical cap or hematoma in the soft tissues. Timely recognition of scapulothoracic disassociation is imperative as there is a high association with neurovascular injuries. The vascular injury may be arterial or venous, with arterial injuries most commonly from intravascular thrombosis [2]. In a series by Damchen et al.,
Emerg Radiol
Fig. 1 Chest radiograph of a 48-year-old avalanche survivor shows the right scapula asymmetrically laterally displaced (arrows) from midline (spinous processes: dashed line). There is increased soft tissue attenuation at the right axilla indicating soft tissue injury and hematoma
88 % of patients had vascular injuries and 94 % of patients had some neurological injury [1]. To avoid uncontrolled bleeding or prolonged limb ischemia, all patients with scapulothoracic disassociation thus warrant CT angiography. Early identification of scapulothoracic disassociation facilitates vascular imaging to be performed as part of the trauma scan, with injection from the contralateral upper extremity to successfully instill contrast and avoid obscuring the region of interest by streak artifact from the contrast bolus. CT best shows the osseous injuries and displacement, vasculature findings, and also demonstrates soft tissue injury to the pectoralis, deltoid, and trapezius muscles. MR imaging is performed 3 to 4 weeks after trauma to allow for stabilization of Wallerian degeneration and development of the most sensitive finding of complete brac h i a l p l e x u s i n j u r y, a p s e u d o m e n i n g o c e l e [ 2 ] .
Fig. 2 CTA images confirm lateral displacement of the right scapula (a arrow) and widening of the right sternoclavicular joint (a arrowhead); there is traumatic thrombotic occlusion of the right axillary artery (b). Fractures of the inferior scapula and segmental right ribs were present (not shown)
Fig. 3 Coronal MR STIR image of the right brachial plexus shows diffusely increased signal and indistinct appearance of the divisions of the right brachial plexus (arrow) without nerve root sleeve avulsion or pseudomeningocele. There is also increased T2 signal throughout the right shoulder musculature without denervation atrophy
Electromyography (EMG) may also be performed to further evaluate denervation and delineate if the injury is pre or post-ganglionic [1]. Classifications for scapulothoracic disassociation recognize that outcome is dependent on if there is isolated musculoskeletal injury or coexistent vascular or peripheral neurological injury [1, 3]. Zelle’s grading stresses the importance of neurological injury on patient outcome, by giving those patients with complete brachial plexus injury the highest grade [3]. In the setting of initial presentation with flail extremity, without sensory or motor function, the return of neurological function is unlikely [3].
Emerg Radiol
In summary, it is important for emergency radiologists to raise the possibility of scapulothoracic disassociation when radiographic clues are present in order to allow assessment of vascular and neurological integrity of the involved extremity. Conflict of interest The authors declare that they have no conflict of interest.
References 1. Damschen DD, Cogbil TH, Siegel MJ (1997) Scapulothoracic dissociation caused by blunt trauma. J Trauma Injury, Infect Crit Care 42(3): 537–540 2. Brucker PU, Gruen GS, Kaufmann RA (2005) Scapulothoracic dissociation: evaluation and management. Injury 36(10):1147–1155 3. Zelle BA, Pape HC, Geric TG et al (2004) Functional outcome following scapulothoracic dissociation. J Bone Joint Surg 86(1):2–8
CASE REPORT
Core curriculum illustration: scapulothoracic disassociation Nupur Verma & Ken F. Linnau
Received: 23 January 2015 / Accepted: 3 February 2015 # American Society of Emergency Radiology 2015
Abstract This is the 14th installment of a series that will highlight one case per publication issue from the bank of cases available online as part of the American Society of Emergency Radiology (ASER) educational resources. Our goal is to generate more interest in and use of our online materials. To view more cases online, please visit the ASER Core Curriculum and Recommendations for Study online at: http://www. aseronline.org/curriculum/toc.htm.
ally displaced right scapula relative to the thoracic cage, widening at the right sternoclavicular joint (Fig. 2a), and complete transection of the right axillary artery (Fig. 2b) for which the patient undergoes operative repair. Subsequent magnetic resonance (MR) imaging performed approximately 1 month later shows diffuse high signal in the brachial plexus (Fig. 3).
Keywords Scapulothoracic disassociation . Upper extremity . Computed tomography angiography . Brachial plexus
Discussion
History A 48-year-old man fell 200 ft during an avalanche while skiing and suffered prolonged extrication. He has a cold pulseless right arm, with loss of sensory and motor function, and is airlifted to the trauma center.
Findings On physical exam, the patient has decreased pulses in the cool and ischemic appearing right upper extremity. Chest radiograph, performed as part of primary trauma survey, shows the right scapula laterally displaced from midline when compared to the left (Fig. 1). Subsequent computer tomographic (CT) angiogram shows posteriorly and laterN. Verma (*) : K. F. Linnau Department of Radiology, University of Washington, 325 Ninth Ave, Box 359728, Seattle, WA 98104, USA e-mail: [email protected]
Scapulothoracic disassociation represents a closed forequarter amputation secondary to severe lateral traction on the upper extremity, most commonly from motorcycle accidents [1]. The injury is characterized by fractures or dislocations separating the upper extremity from the thoracic cage, with swelling and deformity of the chest and proximal upper extremity from underlying soft tissue sheering, edema, and hemorrhage. The patient may present with decreased to absent sensation, reflexes, and distal pulses [1, 2]. As scapulothoracic disassociation is a marker of high-energy trauma; it raises the patient’s likelihood of having other concomitant major injuries, including other orthopedic and central neurological injuries [1]. Recognizing the displacement of the involved extremity’s scapula asymmetrically laterally relative to the midline is often the initial clue on chest radiography. Extensive separation at a clavicle fracture, acromioclavicular separation, or sternoclavicular dislocation may also be seen. Additional findings on radiography may include an apical cap or hematoma in the soft tissues. Timely recognition of scapulothoracic disassociation is imperative as there is a high association with neurovascular injuries. The vascular injury may be arterial or venous, with arterial injuries most commonly from intravascular thrombosis [2]. In a series by Damchen et al.,
Emerg Radiol
Fig. 1 Chest radiograph of a 48-year-old avalanche survivor shows the right scapula asymmetrically laterally displaced (arrows) from midline (spinous processes: dashed line). There is increased soft tissue attenuation at the right axilla indicating soft tissue injury and hematoma
88 % of patients had vascular injuries and 94 % of patients had some neurological injury [1]. To avoid uncontrolled bleeding or prolonged limb ischemia, all patients with scapulothoracic disassociation thus warrant CT angiography. Early identification of scapulothoracic disassociation facilitates vascular imaging to be performed as part of the trauma scan, with injection from the contralateral upper extremity to successfully instill contrast and avoid obscuring the region of interest by streak artifact from the contrast bolus. CT best shows the osseous injuries and displacement, vasculature findings, and also demonstrates soft tissue injury to the pectoralis, deltoid, and trapezius muscles. MR imaging is performed 3 to 4 weeks after trauma to allow for stabilization of Wallerian degeneration and development of the most sensitive finding of complete brac h i a l p l e x u s i n j u r y, a p s e u d o m e n i n g o c e l e [ 2 ] .
Fig. 2 CTA images confirm lateral displacement of the right scapula (a arrow) and widening of the right sternoclavicular joint (a arrowhead); there is traumatic thrombotic occlusion of the right axillary artery (b). Fractures of the inferior scapula and segmental right ribs were present (not shown)
Fig. 3 Coronal MR STIR image of the right brachial plexus shows diffusely increased signal and indistinct appearance of the divisions of the right brachial plexus (arrow) without nerve root sleeve avulsion or pseudomeningocele. There is also increased T2 signal throughout the right shoulder musculature without denervation atrophy
Electromyography (EMG) may also be performed to further evaluate denervation and delineate if the injury is pre or post-ganglionic [1]. Classifications for scapulothoracic disassociation recognize that outcome is dependent on if there is isolated musculoskeletal injury or coexistent vascular or peripheral neurological injury [1, 3]. Zelle’s grading stresses the importance of neurological injury on patient outcome, by giving those patients with complete brachial plexus injury the highest grade [3]. In the setting of initial presentation with flail extremity, without sensory or motor function, the return of neurological function is unlikely [3].
Emerg Radiol
In summary, it is important for emergency radiologists to raise the possibility of scapulothoracic disassociation when radiographic clues are present in order to allow assessment of vascular and neurological integrity of the involved extremity. Conflict of interest The authors declare that they have no conflict of interest.
References 1. Damschen DD, Cogbil TH, Siegel MJ (1997) Scapulothoracic dissociation caused by blunt trauma. J Trauma Injury, Infect Crit Care 42(3): 537–540 2. Brucker PU, Gruen GS, Kaufmann RA (2005) Scapulothoracic dissociation: evaluation and management. Injury 36(10):1147–1155 3. Zelle BA, Pape HC, Geric TG et al (2004) Functional outcome following scapulothoracic dissociation. J Bone Joint Surg 86(1):2–8
