Mesentery and Colon Injuries Secondary to Blunt Trauma"
Diagnostic Radiology
Jack L. Westcott, M.D., and Jay R. V. Smith, M.D. Three cases of colon lesions following blunt trauma are presented to illustrate their varied manifestations. Although these injuries are not as common as those to the small bowel and solid viscera, the radiologist's awareness of them and of their various presentations may be helpful in suggesting the correct diagnosis. The major types of colon injury include mesenteric laceration with blood loss, vascular injury with or without bowel ischemia, intramural hematoma, bowel wall laceration, and delayed cicatricial stenosis. INDEX TERMS:
Colon, wounds and injuries. Mesentery
Radiology 114: 597-600, March 1975
placed by the combination shoulder-lap belt, the incidence of injuries to the abdominal viscera should markedly decrease (17). Although colon injuries may occur alone, they are frequently associated with, and sometimes overshadowed by, injuries to the small bowel, spleen, liver, pancreas, and kidneys. A wide spectrum of colon injuries can be categorized as follows (adapted from McCort, 9): I. Mesenteric laceration A. With hematoma B. With major vessel injury 1. Acute hemorrhage 2. Bowel ischemia a. Complete healing b. Bowel necrosis and perforation c. Delayed ischemic stenosis II. Intramural hematoma A. Acute B. Chronic III. Bowel laceration A. Incomplete (seromuscular tear) B. Complete
NJURIES to the colon after blunt abdominal trauma are much less common than those to the small bowel and other abdominal and retroperitoneal organs (1, 15, 17, 20). However, life-threatening injuries to the large bowel occasionally do occur and have recently been reported with increasing frequency, possibly as a result of the widespread use of lap-type seat belts (6, 14, 16, 17). We have recently observed three cases of serious colon lesions occurring after blunt trauma to the abdomen. These cases are described in the legends of Figures 1-3, and, together with a brief review of the various types of colon injury secondary to trauma, form the basis of this report.
I
DISCUSSION
The mechanisms of colon injury due to blunt trauma appear to be similar to those of the more common injuries to the small bowel. Experimental studies by Williams and Sargent (19) suggest that shearing forces generated by compression between two opposing forces (usually the anterior abdominal wall and the lumbar spine or pelvis) are the major cause of intestinal injuries. Some injuries may also result from the force of a direct blow to the bowel wall, resulting in contusion or laceration. Recently, an association between lap-type seat belts and visceral injuries has been noted (6, 7, 14, 16, 17, 20). If the belt is improperly positioned or if the passenger slides under the belt at impact, the deceleration forces will be absorbed by the abdomen rather than by the iliac crests. Resultant shearing may cause severe injuries to the solid viscera, small and large bowel, lumbar spine, and abdominal musculature. (One of the patients (CASE III) was wearing a lap-type seat belt at the time of injury, but we were unable to obtain this information in the other two cases.) As the lap belt is re1
MESENTERIC LACERATION
The most frequent large bowel injury following blunt trauma is laceration of the mesentery (17). It may occur alone or in association with injuries to the bowel or solid viscera (16, 17). If the laceration is small and major vessels are left intact, injury usually amounts to no more than mesenteric hematoma, and the bowel remains viable (9, 18). If there is major vessel laceration, the patient may present acutely with signs of blood loss (7, 14) or later with signs of bowel ischemia. CASE I represents an example of mesenteric laceration with major arterial injury. The arteriogram revealed a laceration and false aneurysm of the middle colic ar-
From the Department of Radiology, Hartford Hospital, Hartford, Conn. Accepted for publication in October 1974.
597
ah
598
JACK L. WESTCOTT AND JAY R. V. SMITH
,
March
1975
occur (2, 3. 8, 12, 13). In some patients , a delayed bowel stricture develops as the ischemic segment heals (1, 10). It is frequently impossible to determine whether a delayed stricture after trauma is due to ischemia with subsequent scarring or to organization of an intramural hematoma or both. Mays and Noer (10) and Altner (1) reviewed the subject of delayed post-traumatic stenosis of the large bowel and concluded that the most likely explanation was a combination of interstitial hemorrhage and ischemia . They also believed that the ischemia was usually due to small intramural vascular thrombosis or decreased tissue perfusion rather than to major vessel occlusion. INTRAMURAL HEMATOMA
Fig. 1. CASE I. An 18-year-old youth ran his automobile off a highway overpass and landed on the lower level. On admission to hospital. he was found to have brainstem injuries. a right pneumothorax. abdominal wall bruises. a fractured mandible. and multiple facial lacerations. A chest tube was inserted. and tracheostomy was performed. The mandible was wired . The patient's blood pressure was difficult to maintain in spite of multiple transfusions. Because of continued blood loss and abdominal pain, abdominal angiography was performed on the fifteenth hospital day. A superior mesenteric arteriogram demonstrated a false aneurysm arising from the middle colic artery (arrow). This was approximately 2 cm in diameter. There wasopacification of theceliac trunk via a persisting arc of Buhler. At surgery approximately 100 ml of old blood was found in the abdominal cavity, and there was a large hematoma of the left mesocolon. There was slight ecchymosis of the small bowel mesentery. but no sign of active bleeding. The false aneurysm of themiddle colic artery was dissected freeand removed. The postoperative course was uneventful. tery which was the source of major abdominal bleeding. The arteriogram in this case was helpful in locating the site of major injury and in excluding other sources of hemorrhage. but major vessel laceration or thrombosis due to blunt trauma is apparently rare (8, 13). We were able to find only one other case in which mesenteric vascular injury was demonstrated by angiography (4). According to Killen (8), venous thrombosis occurs more frequently than major arterial injury. Presumably most vascular injuries heal completely, but sometimes ischemic colitis develops, and occasionally gangrene and perforation of the involved segment
An intramural hematoma may occur alone or in association with a hematoma of the adjacent mesentery. Spencer et et. (15) reviewed 34 reported cases of acute post-traumatic intestinal hematoma and found that only 8 were in the large bowel. Intramural hematomas probably become symptomatic only if they cause colon obstruction. According to Nance and Crowder (11), acute hematomas are less often symptomatic than chronic ones . As stated earlier, delayed stenosis associated with an organiz ing hematoma may be due in part to bowel ischemia . Most of the reported cases of acute or chronic obstructing hematoma of the colon have been located in the descending colon, but they have also been reported in the sigmoid, cecum, and ascending colon (1, 10. 11). We were unable to find any reports of hematomas involving the transverse colon . In some patients, post-traumatic colon stenosis is not discovered until years after the injury, and in these an association with the remote episode of trauma is unlikely to be made (10). CASE II (Fig. 2) represents an example of stenosis and partial obstruction secondary to an organizing hematoma of the sigmoid-descending colon junction; this became symptomatic two weeks following injury. COLON LACERATION
Lacerations of the colon wall may be single or multiple and vary in severity from incomplete (seromuscular) tears to localized perforations and, rarely, complete bowel transection. Seromuscular tears involve the muscularis and serosa and leave the mucosal layers intact (17). Mays and Noer found that in rabbits the mucosa and muscularis mucosa are the most resistant layers to direct blunt trauma, confirming the clinical observation that incomplete tears in humans involve the serosa and muscularis instead of the mucosa (10, 14, 16). If the injury is severe enough, all of the intestinal layers may be torn, resulting in perforation . Most tears occur along the anti mesenteric border with perforation into the peritoneal cavity (17), but occasionally they
Vol. 114
ME SENTARY AND COLON INJURIES SECONDARY TO BLUNT TRAUMA
599
Diagnostic Radiology
Fig. 2. CASE II. L. P., a 55-year-old male truck driver, was involved in an accident on April 27, 1973, and was admitted to another hospital with a left knee laceration. There was also a large hematoma of the left chest and left side of the abdomen, extending to the left flank ; this was thought to be secondary to blunt trauma from the steering wheel. The patient was discharged following treatment of the knee laceration, and for a week he remained asymptomatic. A decrease in the size and number of stools, nausea, anorexia, and colicky pains in the lower abdomen led to his admission to our hospital on May 12. Physical examination showed a distended abdomen. There was slight tenderness in the left lower quadrant, and an abdominal wall hematoma in that quadrant measured 20 em in its greatest diameter. An abdominal radiograph (A) taken on the sixteenth day after the accident showed dilatation of the large bowel from the cecum to the lower descending colon. This finding was consistent with descending colon obstruction . The patient was placed on a bland diet but failed to respond. Twenty-eight days after trauma, a barium enema examination (B) revealed almost complete obstruction by intramural hematoma (arrows) at the junction of the descending and the sigmoid colon. On May 29 surgery disclosed a chronic inflammatory process involving the lower descending colon and upper sigmoid along with the adjacent mesentery and abdominal wall. There was a large hematoma in the wall of the bowel with thickening of the bowel wall. This was believed to be secondary to venous obstruct ion in the mesentery. The involved segment of colon was resected, and primary anastomosis was performed. The surgical specimen revealed mucosal edema with fat necrosis . The patient had an uneventful postoperative course.
Fig. 3. CASE III. J. S., a 66-year-old woman , was admitted with complaints of increasing abdominal pain of approximately five days duration. She had been in an automobile accident about one week earlier and had been treated in another hospital for lacerations. Radiographs of the chest and abdomen had revealed no abnormalities. Two days prior to admission, she was seen in the Emergency Room of our hospital complaining of abdominal and right shoulder pain. Abdominal and chest radiographs at that time were again "negative," and she was discharged. Physical findings on admission two days later revealed areas of ecchymosis over the right iliac crest, presumably secondary to a lap-type seat belt which was in place at the time of the accident. Abdominal examination revealed tenderness , most marked on the left side. X-ray studies at this time (above) demonstrated a large amount of free air under the right diaphragm, owing to delayed perforation of the sigmoid colon. Because of the history and the amount of free air, the possibility of a colon rupture was suggested. Operation on the same day revealed a perforation along the antimesenteric border at the junction of the sigmoid and the descending colon. There was no evidence of fecal contamination at the site of perforation . Primary anastomosis following resection was performed, and the patient was discharged after an uneventful recovery.
600
JACK L. WESTCOTT AND JAY R. V. SMITH
occur on the mesenteric side resulting in the formation of a retroperitoneal abscess or retroperitoneal gas collection (3, 17). Rarely, with severe trauma, complete transection of the colon may occur (16). While some colon perforations occur immediately after injury, in many patients there is a delay of days or even weeks between the time of trauma and the onset of symptoms and diagnosis. Part of the delay is probably due to the fact that in some cases the colon trauma is overshadowed by more obvious injuries; however, this would not explain the occasional long delay that may occur before a colon laceration becomes obvious. One such sequence was observed in CASE III. Abdominal radiographs immediately following the episode of trauma and again on the fifth day were normal. Abdominal free air was not demonstrated until the seventh day (Fig. 3). Similar and often longer delays from the traumatic episode to the time of discovery of the perforation have been described by other investigators (2, 6, 20). It seems most unlikely that a free perforation would remain undetected for many days. Presumably the initial tear involves the serosal and muscular layers and leaves the mucosa intact. A second later event (? ischemia, ? secondary infection) causes a loss of mucosal integrity and a delayed free perforation. While hematomas and stenoses usually involve the ascending and descending colon, acute perforations are most commonly found in the transverse and sigmoid colon, probably because these areas are more likely to be impinged between the anterior abdominal wall and the lumbar spine (10). Delayed perforations appear to be most common in the cecum and sigmoid colon. RADIOGRAPHIC CHANGES
The radiographic findings in colon trauma vary, depending on the time of study and the type of injury. Rarely, retroperitoneal air (3) or signs of mesenteric vascular disease (8, 9) may be seen on plain radiographs of the abdomen. Normal abdominal x-ray studies are of little significance since a "negative" study does not exclude serious injury to the mesentery, mesenteric vessels, or bowel wall. Obviously, repeat radiographs should be obtained if clinically indicated. Contrast studies of the colon may be normal if the injury is limited to the mesentery and if the bowel wall remains viable. If there is significant arterial or venous injury, the barium enema may reveal changes due to ischemic colitis (3). Intramural hematomas and delayed stenoses due to ischemia or organizing hematoma usually appear as circumferential areas of narrowing and
March 1975
may simulate an annular neoplasm. The location of the lesion may be helpful since the vast majority of delayed cicatricial stenoses have occurred in the descending or sigmoid colon (1, 5, 10). Mesenteric angiography may be useful on occasion (CASE I, Fig. 1), but its routine use in abdominal trauma is probably not warranted because of the infrequency of major mesenteric arterial injury (8, 13). Department of Radiology Hartford Hospital Hartford, Conn. 06115
REFERENCES 1. Altner PC: Constrictive lesions of the colon due to blunt trauma to the abdomen. Surg Gynecol Obstet 118:1257-1262, Jun··1964 2. Blumenberg RM: The seat belt syndrome: sigmoid colon perforation. Ann Surg 165:637-639, Apr 1967 3. Burrell M, Toffler R, Lowman R: Blunt trauma to the abdomen and gastrointestinal tract: plain film and contrast study. Radiol Clin North Am 11:561-578, Dec 1973 4. Campbell OK, Austin RF: Seat-belt injury: injury of the abdominal aorta. Radiology 92: 123-124, Jan 1969 5. Corbett R: Stenosed segment of descending colon associated with trauma. Proc R Soc Med 50:271-272, Apr 1957 6. Doersch KB, Dozier WE: The seat-belt syndrome: the seat belt sign, intestinal and mesenteric injuries. Am J Surg 116:831-833, Dec 1968 7. Gerritsen R, Frobese AS, Pezzi PJ: Unusual abdominal injuries due to seat belts. J Albert Einstein Med Ctr 14:63-66, 1966 8. Killen DA: InjurY'of the superior mesenteric vessels secondary to nonpenetrating abdominal trauma. Am Surg 30:306-312, May 1964 9. McCort JJ: Radiographic examination in blunt abdominal trauma. Philadelphia, Saunders, 1966, pp 112-117; 135~ 141 10. Mays ET, Noer RJ: Colonic stenosis after trauma. J Trauma 6:316-331, May 1966 11. Nance FC, Crowder VH: Intramural hematoma of the colon following blunt trauma to the abdomen. Am Surg 34:85-87, Jan 1968 12. Penn I, Mendels J: Gangrene of the caecum following closed abdominal injury. Br J Surg 50:112-114, Jul 1962 13. Shuck JM, Trump OS: Nonpenetrating abdominal trauma with injury to blood vessels. Am Surg 27:693-697, Oct 1961 14. Snyder CJ: Bowel injuries from automobile seat belts. Am J Surg 123:312-316, Mar 1972 15. Spencer R, Bateman JO, Horn PL: Intramural hematoma of the intestine, a rare cause of intestinal obstruction. Review of the literature and report of a case. Surgery 41:794-804, May 1957 16. Towne JB, Coe JO: Seat belt trauma of the colon. Am J Surg 122:683-685, Nov 1971 17. Williams JS, Kirkpatrick JR: The nature of seat belt injuries. J Trauma 11:207-218, Mar 1971 18. Williams JS, Lies BA Jr, Hale HW Jr: ~he automotive safety belt in saving a life may produce intra-abdominal injuries. J Trauma 6:303-315, May 1966 19. Williams R, Sargent FT: The mechanism of intestinal injury in trauma. J Trauma 3:288-294, May 1963 20. Zacheis HG, Condon RE: Seat belts and intra-abdominal trauma: report of two unusual cases. J Trauma 12:85-90, Jan 1972
Diagnostic Radiology
Jack L. Westcott, M.D., and Jay R. V. Smith, M.D. Three cases of colon lesions following blunt trauma are presented to illustrate their varied manifestations. Although these injuries are not as common as those to the small bowel and solid viscera, the radiologist's awareness of them and of their various presentations may be helpful in suggesting the correct diagnosis. The major types of colon injury include mesenteric laceration with blood loss, vascular injury with or without bowel ischemia, intramural hematoma, bowel wall laceration, and delayed cicatricial stenosis. INDEX TERMS:
Colon, wounds and injuries. Mesentery
Radiology 114: 597-600, March 1975
placed by the combination shoulder-lap belt, the incidence of injuries to the abdominal viscera should markedly decrease (17). Although colon injuries may occur alone, they are frequently associated with, and sometimes overshadowed by, injuries to the small bowel, spleen, liver, pancreas, and kidneys. A wide spectrum of colon injuries can be categorized as follows (adapted from McCort, 9): I. Mesenteric laceration A. With hematoma B. With major vessel injury 1. Acute hemorrhage 2. Bowel ischemia a. Complete healing b. Bowel necrosis and perforation c. Delayed ischemic stenosis II. Intramural hematoma A. Acute B. Chronic III. Bowel laceration A. Incomplete (seromuscular tear) B. Complete
NJURIES to the colon after blunt abdominal trauma are much less common than those to the small bowel and other abdominal and retroperitoneal organs (1, 15, 17, 20). However, life-threatening injuries to the large bowel occasionally do occur and have recently been reported with increasing frequency, possibly as a result of the widespread use of lap-type seat belts (6, 14, 16, 17). We have recently observed three cases of serious colon lesions occurring after blunt trauma to the abdomen. These cases are described in the legends of Figures 1-3, and, together with a brief review of the various types of colon injury secondary to trauma, form the basis of this report.
I
DISCUSSION
The mechanisms of colon injury due to blunt trauma appear to be similar to those of the more common injuries to the small bowel. Experimental studies by Williams and Sargent (19) suggest that shearing forces generated by compression between two opposing forces (usually the anterior abdominal wall and the lumbar spine or pelvis) are the major cause of intestinal injuries. Some injuries may also result from the force of a direct blow to the bowel wall, resulting in contusion or laceration. Recently, an association between lap-type seat belts and visceral injuries has been noted (6, 7, 14, 16, 17, 20). If the belt is improperly positioned or if the passenger slides under the belt at impact, the deceleration forces will be absorbed by the abdomen rather than by the iliac crests. Resultant shearing may cause severe injuries to the solid viscera, small and large bowel, lumbar spine, and abdominal musculature. (One of the patients (CASE III) was wearing a lap-type seat belt at the time of injury, but we were unable to obtain this information in the other two cases.) As the lap belt is re1
MESENTERIC LACERATION
The most frequent large bowel injury following blunt trauma is laceration of the mesentery (17). It may occur alone or in association with injuries to the bowel or solid viscera (16, 17). If the laceration is small and major vessels are left intact, injury usually amounts to no more than mesenteric hematoma, and the bowel remains viable (9, 18). If there is major vessel laceration, the patient may present acutely with signs of blood loss (7, 14) or later with signs of bowel ischemia. CASE I represents an example of mesenteric laceration with major arterial injury. The arteriogram revealed a laceration and false aneurysm of the middle colic ar-
From the Department of Radiology, Hartford Hospital, Hartford, Conn. Accepted for publication in October 1974.
597
ah
598
JACK L. WESTCOTT AND JAY R. V. SMITH
,
March
1975
occur (2, 3. 8, 12, 13). In some patients , a delayed bowel stricture develops as the ischemic segment heals (1, 10). It is frequently impossible to determine whether a delayed stricture after trauma is due to ischemia with subsequent scarring or to organization of an intramural hematoma or both. Mays and Noer (10) and Altner (1) reviewed the subject of delayed post-traumatic stenosis of the large bowel and concluded that the most likely explanation was a combination of interstitial hemorrhage and ischemia . They also believed that the ischemia was usually due to small intramural vascular thrombosis or decreased tissue perfusion rather than to major vessel occlusion. INTRAMURAL HEMATOMA
Fig. 1. CASE I. An 18-year-old youth ran his automobile off a highway overpass and landed on the lower level. On admission to hospital. he was found to have brainstem injuries. a right pneumothorax. abdominal wall bruises. a fractured mandible. and multiple facial lacerations. A chest tube was inserted. and tracheostomy was performed. The mandible was wired . The patient's blood pressure was difficult to maintain in spite of multiple transfusions. Because of continued blood loss and abdominal pain, abdominal angiography was performed on the fifteenth hospital day. A superior mesenteric arteriogram demonstrated a false aneurysm arising from the middle colic artery (arrow). This was approximately 2 cm in diameter. There wasopacification of theceliac trunk via a persisting arc of Buhler. At surgery approximately 100 ml of old blood was found in the abdominal cavity, and there was a large hematoma of the left mesocolon. There was slight ecchymosis of the small bowel mesentery. but no sign of active bleeding. The false aneurysm of themiddle colic artery was dissected freeand removed. The postoperative course was uneventful. tery which was the source of major abdominal bleeding. The arteriogram in this case was helpful in locating the site of major injury and in excluding other sources of hemorrhage. but major vessel laceration or thrombosis due to blunt trauma is apparently rare (8, 13). We were able to find only one other case in which mesenteric vascular injury was demonstrated by angiography (4). According to Killen (8), venous thrombosis occurs more frequently than major arterial injury. Presumably most vascular injuries heal completely, but sometimes ischemic colitis develops, and occasionally gangrene and perforation of the involved segment
An intramural hematoma may occur alone or in association with a hematoma of the adjacent mesentery. Spencer et et. (15) reviewed 34 reported cases of acute post-traumatic intestinal hematoma and found that only 8 were in the large bowel. Intramural hematomas probably become symptomatic only if they cause colon obstruction. According to Nance and Crowder (11), acute hematomas are less often symptomatic than chronic ones . As stated earlier, delayed stenosis associated with an organiz ing hematoma may be due in part to bowel ischemia . Most of the reported cases of acute or chronic obstructing hematoma of the colon have been located in the descending colon, but they have also been reported in the sigmoid, cecum, and ascending colon (1, 10. 11). We were unable to find any reports of hematomas involving the transverse colon . In some patients, post-traumatic colon stenosis is not discovered until years after the injury, and in these an association with the remote episode of trauma is unlikely to be made (10). CASE II (Fig. 2) represents an example of stenosis and partial obstruction secondary to an organizing hematoma of the sigmoid-descending colon junction; this became symptomatic two weeks following injury. COLON LACERATION
Lacerations of the colon wall may be single or multiple and vary in severity from incomplete (seromuscular) tears to localized perforations and, rarely, complete bowel transection. Seromuscular tears involve the muscularis and serosa and leave the mucosal layers intact (17). Mays and Noer found that in rabbits the mucosa and muscularis mucosa are the most resistant layers to direct blunt trauma, confirming the clinical observation that incomplete tears in humans involve the serosa and muscularis instead of the mucosa (10, 14, 16). If the injury is severe enough, all of the intestinal layers may be torn, resulting in perforation . Most tears occur along the anti mesenteric border with perforation into the peritoneal cavity (17), but occasionally they
Vol. 114
ME SENTARY AND COLON INJURIES SECONDARY TO BLUNT TRAUMA
599
Diagnostic Radiology
Fig. 2. CASE II. L. P., a 55-year-old male truck driver, was involved in an accident on April 27, 1973, and was admitted to another hospital with a left knee laceration. There was also a large hematoma of the left chest and left side of the abdomen, extending to the left flank ; this was thought to be secondary to blunt trauma from the steering wheel. The patient was discharged following treatment of the knee laceration, and for a week he remained asymptomatic. A decrease in the size and number of stools, nausea, anorexia, and colicky pains in the lower abdomen led to his admission to our hospital on May 12. Physical examination showed a distended abdomen. There was slight tenderness in the left lower quadrant, and an abdominal wall hematoma in that quadrant measured 20 em in its greatest diameter. An abdominal radiograph (A) taken on the sixteenth day after the accident showed dilatation of the large bowel from the cecum to the lower descending colon. This finding was consistent with descending colon obstruction . The patient was placed on a bland diet but failed to respond. Twenty-eight days after trauma, a barium enema examination (B) revealed almost complete obstruction by intramural hematoma (arrows) at the junction of the descending and the sigmoid colon. On May 29 surgery disclosed a chronic inflammatory process involving the lower descending colon and upper sigmoid along with the adjacent mesentery and abdominal wall. There was a large hematoma in the wall of the bowel with thickening of the bowel wall. This was believed to be secondary to venous obstruct ion in the mesentery. The involved segment of colon was resected, and primary anastomosis was performed. The surgical specimen revealed mucosal edema with fat necrosis . The patient had an uneventful postoperative course.
Fig. 3. CASE III. J. S., a 66-year-old woman , was admitted with complaints of increasing abdominal pain of approximately five days duration. She had been in an automobile accident about one week earlier and had been treated in another hospital for lacerations. Radiographs of the chest and abdomen had revealed no abnormalities. Two days prior to admission, she was seen in the Emergency Room of our hospital complaining of abdominal and right shoulder pain. Abdominal and chest radiographs at that time were again "negative," and she was discharged. Physical findings on admission two days later revealed areas of ecchymosis over the right iliac crest, presumably secondary to a lap-type seat belt which was in place at the time of the accident. Abdominal examination revealed tenderness , most marked on the left side. X-ray studies at this time (above) demonstrated a large amount of free air under the right diaphragm, owing to delayed perforation of the sigmoid colon. Because of the history and the amount of free air, the possibility of a colon rupture was suggested. Operation on the same day revealed a perforation along the antimesenteric border at the junction of the sigmoid and the descending colon. There was no evidence of fecal contamination at the site of perforation . Primary anastomosis following resection was performed, and the patient was discharged after an uneventful recovery.
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JACK L. WESTCOTT AND JAY R. V. SMITH
occur on the mesenteric side resulting in the formation of a retroperitoneal abscess or retroperitoneal gas collection (3, 17). Rarely, with severe trauma, complete transection of the colon may occur (16). While some colon perforations occur immediately after injury, in many patients there is a delay of days or even weeks between the time of trauma and the onset of symptoms and diagnosis. Part of the delay is probably due to the fact that in some cases the colon trauma is overshadowed by more obvious injuries; however, this would not explain the occasional long delay that may occur before a colon laceration becomes obvious. One such sequence was observed in CASE III. Abdominal radiographs immediately following the episode of trauma and again on the fifth day were normal. Abdominal free air was not demonstrated until the seventh day (Fig. 3). Similar and often longer delays from the traumatic episode to the time of discovery of the perforation have been described by other investigators (2, 6, 20). It seems most unlikely that a free perforation would remain undetected for many days. Presumably the initial tear involves the serosal and muscular layers and leaves the mucosa intact. A second later event (? ischemia, ? secondary infection) causes a loss of mucosal integrity and a delayed free perforation. While hematomas and stenoses usually involve the ascending and descending colon, acute perforations are most commonly found in the transverse and sigmoid colon, probably because these areas are more likely to be impinged between the anterior abdominal wall and the lumbar spine (10). Delayed perforations appear to be most common in the cecum and sigmoid colon. RADIOGRAPHIC CHANGES
The radiographic findings in colon trauma vary, depending on the time of study and the type of injury. Rarely, retroperitoneal air (3) or signs of mesenteric vascular disease (8, 9) may be seen on plain radiographs of the abdomen. Normal abdominal x-ray studies are of little significance since a "negative" study does not exclude serious injury to the mesentery, mesenteric vessels, or bowel wall. Obviously, repeat radiographs should be obtained if clinically indicated. Contrast studies of the colon may be normal if the injury is limited to the mesentery and if the bowel wall remains viable. If there is significant arterial or venous injury, the barium enema may reveal changes due to ischemic colitis (3). Intramural hematomas and delayed stenoses due to ischemia or organizing hematoma usually appear as circumferential areas of narrowing and
March 1975
may simulate an annular neoplasm. The location of the lesion may be helpful since the vast majority of delayed cicatricial stenoses have occurred in the descending or sigmoid colon (1, 5, 10). Mesenteric angiography may be useful on occasion (CASE I, Fig. 1), but its routine use in abdominal trauma is probably not warranted because of the infrequency of major mesenteric arterial injury (8, 13). Department of Radiology Hartford Hospital Hartford, Conn. 06115
REFERENCES 1. Altner PC: Constrictive lesions of the colon due to blunt trauma to the abdomen. Surg Gynecol Obstet 118:1257-1262, Jun··1964 2. Blumenberg RM: The seat belt syndrome: sigmoid colon perforation. Ann Surg 165:637-639, Apr 1967 3. Burrell M, Toffler R, Lowman R: Blunt trauma to the abdomen and gastrointestinal tract: plain film and contrast study. Radiol Clin North Am 11:561-578, Dec 1973 4. Campbell OK, Austin RF: Seat-belt injury: injury of the abdominal aorta. Radiology 92: 123-124, Jan 1969 5. Corbett R: Stenosed segment of descending colon associated with trauma. Proc R Soc Med 50:271-272, Apr 1957 6. Doersch KB, Dozier WE: The seat-belt syndrome: the seat belt sign, intestinal and mesenteric injuries. Am J Surg 116:831-833, Dec 1968 7. Gerritsen R, Frobese AS, Pezzi PJ: Unusual abdominal injuries due to seat belts. J Albert Einstein Med Ctr 14:63-66, 1966 8. Killen DA: InjurY'of the superior mesenteric vessels secondary to nonpenetrating abdominal trauma. Am Surg 30:306-312, May 1964 9. McCort JJ: Radiographic examination in blunt abdominal trauma. Philadelphia, Saunders, 1966, pp 112-117; 135~ 141 10. Mays ET, Noer RJ: Colonic stenosis after trauma. J Trauma 6:316-331, May 1966 11. Nance FC, Crowder VH: Intramural hematoma of the colon following blunt trauma to the abdomen. Am Surg 34:85-87, Jan 1968 12. Penn I, Mendels J: Gangrene of the caecum following closed abdominal injury. Br J Surg 50:112-114, Jul 1962 13. Shuck JM, Trump OS: Nonpenetrating abdominal trauma with injury to blood vessels. Am Surg 27:693-697, Oct 1961 14. Snyder CJ: Bowel injuries from automobile seat belts. Am J Surg 123:312-316, Mar 1972 15. Spencer R, Bateman JO, Horn PL: Intramural hematoma of the intestine, a rare cause of intestinal obstruction. Review of the literature and report of a case. Surgery 41:794-804, May 1957 16. Towne JB, Coe JO: Seat belt trauma of the colon. Am J Surg 122:683-685, Nov 1971 17. Williams JS, Kirkpatrick JR: The nature of seat belt injuries. J Trauma 11:207-218, Mar 1971 18. Williams JS, Lies BA Jr, Hale HW Jr: ~he automotive safety belt in saving a life may produce intra-abdominal injuries. J Trauma 6:303-315, May 1966 19. Williams R, Sargent FT: The mechanism of intestinal injury in trauma. J Trauma 3:288-294, May 1963 20. Zacheis HG, Condon RE: Seat belts and intra-abdominal trauma: report of two unusual cases. J Trauma 12:85-90, Jan 1972
