Refer to: Silsby JJ: Pressure gun injection injuries of the hand. West J Med 125:271-276, Oct 1976
Pressure Gun Injection Injuries of the Hand JOHN J. SILSBY, MD, Sepulveda, California
Pressure gun injection injuries are becoming increasingly common. Their effect on the fingers and hands, especially when improperly managed, can be devastating. Therefore it is important to review features, clinical course, anatomic distribution and operative management of such injuries. If a useful hand and fingers are to be attained, rapid and thorough decompression and debridement of these injuries are essential.
PRESSURE GUN injection injuries involve the injection of an industrial substance, usually paint or grease, into the hand at pressures ranging from 750 pounds per square inch to 12,000 pounds per square inch. The object of this review is to further publicize this type of injury and to emphasize the extreme urgency of appropriate surgical care. Pressure gun injection injuries have received emphasis in the surgical literature, major articles being those by Stark and co-workers"2 and Waters and co-workers,3 but there are still too many cases in which necessary treatment is delayed. Recognition of the potential severity and urgent nature of paint or grease gun injuries is the key to successful management. Rees, in 1937, was the first to describe this injury. Scattered case reports have accumulated since then, and there are now approximately 100 cases reported in the literature. However, these injuries are much more common than the number of reports would indicate and as industry finds more uses for high pressure airless guns, it seems The author is Chief, Section of Plastic Surgery, Veterans Administration Hospital, Sepulveda, and Assistant Professor of Surgery in Residence, University of California, Los Angeles, Center for the Health Sciences. Submitted March 4, 1976. Reprint requests to: John J. Silsby, MD, Department of Surgery, UCLA Center for the Health Sciences, Los Angeles, CA 90024.
likely that more of these injuries with a wider range of injected materials will be seen. Pressure gun injuries fall into two categories, distinguished by different clinical courses. The most commonly injected substances are paint and related solvents, stains and thinners. Water-base paint is the least locally toxic of the common paints, followed by roofing paints and other types of outdoor paints, and the most toxic substance is turpentine. These are complex chemicals, not amenable to neutralization nor dissolution. The injuries caused by paint are characterized by a very intense initial inflammatory reaction. Minimal delay is the key to a successful outcome in the management of paint gun injuries. If decompression and debridement is carried out within four hours of injury, the prospect for attaining a functioning hand is fairly good. If 12 hours or more has passed since injury, the functional results are usually poor and serious consideration should be given to primary amputation of the involved digit. The second category of pressure gun injuries involves grease guns. These injuries are characterized by a less intense initial inflammatory reaction, but by more frequent delayed abscesses and more residual fibrosis. THE WESTERN JOURNAL OF MEDICINE
271
PRESSURE GUN INJURIES
The management of these injuries in the 1940's and 1950's was nonoperative, with the usual result being amputation. It gradually became appreciated that operative removal of the injected material was the only way a functional finger or hand could be obtained. Delayed surgical care yields a result similar to nonoperative management. The reason that prompt surgical decompression and debridement is essential is the rapid onset of severe ischemia in the injected finger. The development of ischemia is much more pronounced in pressure gun injuries involving paint than in those involving grease. If a paint gun injury is seen 30 to 60 minutes after injection, the entrance wound will be a small puncture site and the finger will not be greatly swollen or painful, and will probably have a nearly full range of motion. The same finger an hour or two later will have become painful and swollen, and significant cyanosis will TVe.ndon shea.
have developed. The benign appearance of the early injury, of course, is responsible for the fact that the severity of the injury is often not appreciated. When it becomes apparent to the patient that the condition of the injured finger is deteriorating, much of the damage is already irreversible. It seems likely that the basic cause of the ischemia is the rapid development of severe edema secondary to the inflammatory response to the foreign material. It is the decompression of the swollen finger that is at least as important as removal of the foreign material. An additional cause of digital ischemia is the frequent occurrence of thrombosis of one or both of the digital arteries.
Anatomy The distribution of the injected substance is determined by a combination of the pressure of injection and the fascial planes of the finger and hand. At the site of injection and around it, the injected substance will permeate all the tissue. The neurovascular bundles in the area will be completely infiltrated. The infiltration of the nerve with the injected substance accounts for the hypesthesia often noted on initial examination of pressure gun injected fingers. This initial absence of pain may further mislead the initial examiner
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RadKic-,1 Lbursa Figure 1.-The location of tendon sheaths and bursae in the hand which may be involved in a pressure gun
injury.
272
OCTOBER 1976 * 125 * 4
Figure 2.-A photograph illustrating the early benign appearance of a paint gun injury.
PRESSURE GUN INJURIES
into underestimating the severity of the wound. Involvement of the tendon sheath presents a severe problem because its involvement nearly assures residual stiffness. Experimentally it has been found that the thinner portion of the sheath, over the phalangeal flexion creases, is readily penetrated and if the site of injection is over the flexion creases, flexor tendon sheath involvement is likely. The thicker portions of the sheath over the shafts of the phalanges are not so readily involved. In the operative management of this injury the sheath should be opened sufficiently to determine whether or not involvement is present. The course of the injected material, after leaving the finger, depends mostly on which digit is injured (Figure 1). In the thumb the material often involves the thenar muscles with greater or lesser damage. If the flexor pollicis longus tendon sheath is involved, the substance may enter the radial bursa and consequently involve the struc-
tures in the carpal canal, or can enter the retroflexor space of Parona in the wrist, or finally can enter the ulnar bursa and involve the flexor tendon sheath of the fifth finger in a retrograde manner. Therefore, operative management of an injection injury to the thumb may necessitate a carpal tunnel decompression. Injection of the index finger, probably the finger most commonly involved, may extend into the subcutaneous tissue of the palm and if the flexor tendon sheath is involved the thenar space may also become involved. Similar patterns of distribution are seen in the long and ring fingers. However, if the flexor tendon sheaths are involved the injected material will spread to the midpalmar space. In the case of the long and ring fingers, as well as the index, the force of injection can be sufficient to drive the paint into the carpal canal. Appropriate operative management dictates pursuit of the injected material as far as it appears to go. Finally, the possible distribution of the injected substance in the little finger is analogous to the pattern in the thumb; the hypothenar muscles can be injured and the spread may be into the ulnar bursa, space of Parona and the carpal tunnel.
Clinical Presentatlon The typical case is that of a young man whose paint gun has malfunctioned and who wipes off *iz
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Pressure Gun Injection Injuries of the Hand JOHN J. SILSBY, MD, Sepulveda, California
Pressure gun injection injuries are becoming increasingly common. Their effect on the fingers and hands, especially when improperly managed, can be devastating. Therefore it is important to review features, clinical course, anatomic distribution and operative management of such injuries. If a useful hand and fingers are to be attained, rapid and thorough decompression and debridement of these injuries are essential.
PRESSURE GUN injection injuries involve the injection of an industrial substance, usually paint or grease, into the hand at pressures ranging from 750 pounds per square inch to 12,000 pounds per square inch. The object of this review is to further publicize this type of injury and to emphasize the extreme urgency of appropriate surgical care. Pressure gun injection injuries have received emphasis in the surgical literature, major articles being those by Stark and co-workers"2 and Waters and co-workers,3 but there are still too many cases in which necessary treatment is delayed. Recognition of the potential severity and urgent nature of paint or grease gun injuries is the key to successful management. Rees, in 1937, was the first to describe this injury. Scattered case reports have accumulated since then, and there are now approximately 100 cases reported in the literature. However, these injuries are much more common than the number of reports would indicate and as industry finds more uses for high pressure airless guns, it seems The author is Chief, Section of Plastic Surgery, Veterans Administration Hospital, Sepulveda, and Assistant Professor of Surgery in Residence, University of California, Los Angeles, Center for the Health Sciences. Submitted March 4, 1976. Reprint requests to: John J. Silsby, MD, Department of Surgery, UCLA Center for the Health Sciences, Los Angeles, CA 90024.
likely that more of these injuries with a wider range of injected materials will be seen. Pressure gun injuries fall into two categories, distinguished by different clinical courses. The most commonly injected substances are paint and related solvents, stains and thinners. Water-base paint is the least locally toxic of the common paints, followed by roofing paints and other types of outdoor paints, and the most toxic substance is turpentine. These are complex chemicals, not amenable to neutralization nor dissolution. The injuries caused by paint are characterized by a very intense initial inflammatory reaction. Minimal delay is the key to a successful outcome in the management of paint gun injuries. If decompression and debridement is carried out within four hours of injury, the prospect for attaining a functioning hand is fairly good. If 12 hours or more has passed since injury, the functional results are usually poor and serious consideration should be given to primary amputation of the involved digit. The second category of pressure gun injuries involves grease guns. These injuries are characterized by a less intense initial inflammatory reaction, but by more frequent delayed abscesses and more residual fibrosis. THE WESTERN JOURNAL OF MEDICINE
271
PRESSURE GUN INJURIES
The management of these injuries in the 1940's and 1950's was nonoperative, with the usual result being amputation. It gradually became appreciated that operative removal of the injected material was the only way a functional finger or hand could be obtained. Delayed surgical care yields a result similar to nonoperative management. The reason that prompt surgical decompression and debridement is essential is the rapid onset of severe ischemia in the injected finger. The development of ischemia is much more pronounced in pressure gun injuries involving paint than in those involving grease. If a paint gun injury is seen 30 to 60 minutes after injection, the entrance wound will be a small puncture site and the finger will not be greatly swollen or painful, and will probably have a nearly full range of motion. The same finger an hour or two later will have become painful and swollen, and significant cyanosis will TVe.ndon shea.
have developed. The benign appearance of the early injury, of course, is responsible for the fact that the severity of the injury is often not appreciated. When it becomes apparent to the patient that the condition of the injured finger is deteriorating, much of the damage is already irreversible. It seems likely that the basic cause of the ischemia is the rapid development of severe edema secondary to the inflammatory response to the foreign material. It is the decompression of the swollen finger that is at least as important as removal of the foreign material. An additional cause of digital ischemia is the frequent occurrence of thrombosis of one or both of the digital arteries.
Anatomy The distribution of the injected substance is determined by a combination of the pressure of injection and the fascial planes of the finger and hand. At the site of injection and around it, the injected substance will permeate all the tissue. The neurovascular bundles in the area will be completely infiltrated. The infiltration of the nerve with the injected substance accounts for the hypesthesia often noted on initial examination of pressure gun injected fingers. This initial absence of pain may further mislead the initial examiner
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RadKic-,1 Lbursa Figure 1.-The location of tendon sheaths and bursae in the hand which may be involved in a pressure gun
injury.
272
OCTOBER 1976 * 125 * 4
Figure 2.-A photograph illustrating the early benign appearance of a paint gun injury.
PRESSURE GUN INJURIES
into underestimating the severity of the wound. Involvement of the tendon sheath presents a severe problem because its involvement nearly assures residual stiffness. Experimentally it has been found that the thinner portion of the sheath, over the phalangeal flexion creases, is readily penetrated and if the site of injection is over the flexion creases, flexor tendon sheath involvement is likely. The thicker portions of the sheath over the shafts of the phalanges are not so readily involved. In the operative management of this injury the sheath should be opened sufficiently to determine whether or not involvement is present. The course of the injected material, after leaving the finger, depends mostly on which digit is injured (Figure 1). In the thumb the material often involves the thenar muscles with greater or lesser damage. If the flexor pollicis longus tendon sheath is involved, the substance may enter the radial bursa and consequently involve the struc-
tures in the carpal canal, or can enter the retroflexor space of Parona in the wrist, or finally can enter the ulnar bursa and involve the flexor tendon sheath of the fifth finger in a retrograde manner. Therefore, operative management of an injection injury to the thumb may necessitate a carpal tunnel decompression. Injection of the index finger, probably the finger most commonly involved, may extend into the subcutaneous tissue of the palm and if the flexor tendon sheath is involved the thenar space may also become involved. Similar patterns of distribution are seen in the long and ring fingers. However, if the flexor tendon sheaths are involved the injected material will spread to the midpalmar space. In the case of the long and ring fingers, as well as the index, the force of injection can be sufficient to drive the paint into the carpal canal. Appropriate operative management dictates pursuit of the injected material as far as it appears to go. Finally, the possible distribution of the injected substance in the little finger is analogous to the pattern in the thumb; the hypothenar muscles can be injured and the spread may be into the ulnar bursa, space of Parona and the carpal tunnel.
Clinical Presentatlon The typical case is that of a young man whose paint gun has malfunctioned and who wipes off *iz
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