False Aneurysm of the Abdominal Aorta Due to Blunt Trauma GULSHAN K. SETHI, M.D., STEWART M. SCOTT, M.D., TIMOTHY TAKARO, M.D.
Nonpenetrating trauma to the abdominal aorta is uncommon and the development of a traumatic abdominal aortic aneurysm is even more rare. The victims of blunt trauma to the abdomen should be examined for diminution or absence of femoral pulses, especially if numbness, diminished sensations, or motor weakness appear following trauma. If pulse abnormalities are present, aortography should be performed promptly to exclude aortic disruption or dissection. Immediate surgery should be performed once the diagnosis of aortic disruption is made. To our knowledge, this is the second reported case of successful surgical treatment of a false aneurysm of the abdominal aorta following nonpenetrating trauma.
N?NPENETRATING TRAUMA to the abdomen may cause injury to any of the intra abdominal organs. Abdominal aortic injuries and especially traumatic rupture of the abdominal aorta are uncommon. It is possible that most of these patients die before medical assistance can be given to them, or they are in extremis and are never operated upon and do not have autopsy examination.13 Even more rare than traumatic rupture of the abdominal aorta is the development of a traumatic aneurysm of the abdominal aorta.5 Because of the rare occurrence of such a complication, we are reporting the case of a patient who developed a Submitted for publication April 2, 1975. Reprint requests: Gulshan K. Sethi, M.D., Veterans Administration Hospital, Oteen, N.C. 28805
From the Division of Thoracic and Cardiovascular Surgery, Veterans Administration Hospital, Oteen, North Carolina
false aneurysm of the abdominal aorta following blunt trauma. A review of the pathogenesis and management of abdominal aortic injuries due to blunt trauma is also included. Case Report A 46-year-old negro man, who was a chronic alcoholic, had a fall from a flight of stairs about 4 weeks prior to admission. He struck his chest and abdomen on the stairs, but he did not seek medical help. About 48 hours before admission to another hospital, he began having severe pain in the abdomen and back, as well as in the left thigh and leg. The pain gradually became worse, to the extent that he could not move from his bed. In the past, the patient had been seen many times in the Outpatient Clinic with various injuries, including fractured ribs, abrasions and contusions of various parts of the body. Physical examination revealed a thin male in acute distress due to abdominal and back pain. Blood pressure was 150/80 mm Hg pulse was 80 per minute, and respirations 20 per minute. A pulsatile abdominal mass measuring 8 by 10 inches was palpable in the mid epigastric region. The femoral and peripheral pulses were palpable bilaterally and were of equal volume. No bruit was heard. Chest x-ray showed multiple bilateral healed rib fractures. The electrocardiogram was normal. Hemoglobin was 11.0 gm% and hematocrit 33%. Blood chemistry determinations were normal.
Ann. Surg. July 1975 SETHI, SCOTT AND TAKARO ner recommended by Bentley Laboratories, Inc.* Ten thousand units of heparin were administered intravenously. The aorta was crossclamped below the renal arteries and the iliac arteries were clamped distally. The aneurysm was incised anteriorly, and immediately about 1,000 mls of blood were aspirated and circulated to the patient by the autotransfusion pump. After opening the aneurysm, it became apparent that the patient had an anterior transverse laceration of the aorta, and that the mass occupying most of the retroperitoneal area was a false aneurysm. The lacerated ends of the anterior wall of the aorta were about 4 cms apart and primary closure of the aorta was not possible. The aorta was transected and an 18 mm tubular knitted dacron arterial prosthesis** was interposed between the cut ends of the aorta. Postoperatively, he had good peripheral pulses. On the fourteenth day, he developed azotemia which responded promptly to fluid administration. Pain in the left lower extremity continued, and he later developed weakness of the quadriceps muscles. A postoperative intravenous pyelogram showed prompt function of both kidneys, and the left kidney was returned to its normal anatomical position. At 6 months' follow-up, he is doing well, and the left leg pain and weakness of the quadriceps muscles have improved. Renal function studies and intravenous pyelogram are normal.
Discussion Over 95%o of traumatic aortic injuries involve the thoracic aorta at points of fixation which include the base of the heart, the attachment of the ligamentum arFIG. 1. Preoperative intravenous pyelogram showing normally functionand the diaphragm at the hiatus.' Nonpenetratteriosum, ing kidneys bilaterally. The right kidney is in its normal anatomical position, but the left kidney (big arrow) is displaced superiorly and ing traumatic injuries to the abdominal aorta are uncomlaterally by an extrinsic mass (small arrows) and has attained an almost mon because it is well protected by its retroperitoneal horizontal position. location and by the rigid vertebral column. In 347 autopsy cases of nonpenetrating traumatic injury of the An intravenous pyelogram revealed normally functioning kidbilaterally. However, the left kidney was markedly displaced superiorly and laterally by an extrinsic mass, attaining an almost horizontal position (Fig. 1). Over the next 24 hours following admission, his back pain became worse and the hemoglobin level dropped from 11 to 9 gm%. He was transferred to Oteen Veterans Administration Hospital with a presumptive diagnosis of rupturing abdominal aortic aneurysm. Examination at this time showed a patient with obtunded sensorium. The previously described pulsatile abdominal mass was now also tender. There was also marked tenderness in the lower back. Vital signs were unchanged. Peripheral pulses were normal. The patient was immediately taken to the operating room. A radial arterial line and a central venous line were inserted for monitoring purposes, and the abdomen was opened through a midline incision. Exploration of the abdomen did not reveal evidence of recent or remote intra-abdominal bleeding, or any injury to the visceral organs. The pulsatile mass, measuring 8 by 10 inches occupied almost the whole left retroperitoneal area. The right kidney was in its normal anatomical position. The left kidney was displaced cephalad and laterally by the pulsatile mass and was lying under the spleen (Fig. 2). The left renal vein was stretched over the aorta so that to obtain control of the aorta proximal to the aneurysm was technically very difficult. Accordingly, the left renal vein was divided and access to the infrarenal aorta was obtained. Distally the iliac arteries were dissected and umbilical tapes were passed around them. Because of the limited availability of blood and the danger of uncontrollable bleeding, autotransfusion was used in the manneys
*Bentley Laboratories, Inc., 17502 Armstrong Avenue, Irvine, Calif. 92705 **USCI, A Division of C. R. Bard, Inc., Box 566, Billerica, Mass. 01821
ADRENAl,, SIrE OF TRANSECrION OF LEFT
FIG. 2. Schematic diagram showing the findings at operation.
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FALSE ANEURYSM OF THE ABDOMINAL AORTA
aorta, only 16 instances of injury to the abdominal aorta were recorded.f'5 In a review of over 1300 cases of nonpenetrating abdominal trauma, abdominal vascular injuries were noted in 16 instances and the abdominal aorta was involved only once.6 The mechanism of blunt abdominal aortic injury is related to direct and indirect forces. The aorta is relatively fixed by the lumbar vessels and vertebral column. Direct force may cause aortic rupture from the resultant pressure against the "trapped" aorta or by laceration of the vessels from associated vertebral fracture.9 The severity of atheromatous changes and the magnitude of blunt force determine whether complete disruption of the aorta occurs or only intimal tearing with subsequent mural dissection.2 The indirect forces are created by 1) transmission of the pressure of the initiating force through adjacent organs to the aortic wall with resultant compression against a relatively incompressible blood column, the existing intravascular pressure, and the elasticity of the aortic wall, and 2) by the rate of deceleration between free and relatively fixed segments of the aorta, resulting in a shearing force and aortic rupture.16 Other factors contributing to blunt aortic injuries include the physique of the individual, the character and suddenness of the trauma, and the state of contraction of the musculature of the abdominal wall. The thin build and suddenness of the injury may have facilitated the aortic laceration in our patient. The most common causes of abdominal aortic injuries due to nonpenetrating trauma are automobile accidents or direct blows to the abdomen. Occasionally, as in our patient, direct trauma to the abdomen, by a fall from a height, may also cause aortic rupture. Campbell and Austin3 reported a case of initmal tear and thrombosis of the distal abdominal aorta due to seat belt injury. Ngu and Konstam8 reported intimal tear and thrombosis of distal aorta in a thin 37-year-old woman who was struck across the mid abdomen by the end of a surfboard. The right leg was paralyzed and motor power and sensation to pin prick were grossly impaired in the left lower extremity. Both lower extremities were ischemic. The thrombus was removed from the aorta and the displaced intima was sutured back to the proximal edge of the tear. Normal motor function and sensation returned rapidly in both legs following surgery. Nonpenetrating abdominal injuries may cause occlusion, rupture, or transection of the aorta, or may produce dissecting or false aortic aneurysms. Acute abdominal aortic occlusion is usually manifested by claudication, cyanosis, coldness, numbness, weakness, and impending gangrene of the lower extremities. The femoral pulses are usually absent. Severe neurological complications ranging from mild sensory loss to paraplegia may occur.7 Ischemic changes of nerves may also explain persistent
35 paresthesia and subjective weakness of legs. The weakness of the quadriceps muscles, as in our patient, is probably due to femoral nerve entrapment caused by the retroperitoneal hematoma." Usually it responds to physiotherapy and may take many months for complete recovery. In case of known severe abdominal trauma, unexplained shock and development of flank ecchymosis should cause suspicion of retroperitoneal bleeding, which could be due to rupture or transection of the abdominal aorta. Occasionally, a pulse may be palpable distal to the point of arterial disruption because the pressure waves may be transmitted through the freshly formed soft clots, although the lumen of the vessel may be completely occluded. In reviewing 259 arterial injuries, Perry and associates10 noted that 10%o of the proven injuries had equal distal pulses, and Drapanas and his associates4 reported this incidence to be as high as 27%. Aortography should be considered in all patients who sustain severe blunt trauma to the abdomen and who are suspected to have suffered aortic or visceral arterial injuries. Immediate operation should be performed when the diagnosis of abdominal aortic disruption is made or suspected. Apart from the danger of exsanguination secondary to adventitial rupture, the results of aortic reconstructive surgery for aortic injury appear to be time related.2 At laparotomy, the retroperitoneal area should be carefully examined. Subadventitial discoloration, pulse discrepancies, and turbulent flow through the vessels may be detected. They indicate aortic injury. Usually a large retroperitoneal hematoma due to pelvic fractures is not explored unless concern about a major vascular injury exists. The technique for arterial reconstruction is dictated by the findings at operation. If thromboembolectomy and primary repair are possible, then it is the procedure of choice. Distal intimal flaps should be adequately tethered with sutures to avoid further dissection. If there is extensive destruction of the aorta, a vascular prosthesis should be interposed. Intraoperative angiography is indicated if distal pulses are not palpable after aortic reconstruction. Occasionally, as in our case, it may be necessary to ransect the left renal vein to gain access to the aorta proximal to the site of rupture. The left renal vein can be safely interrupted without producing permanent damage to the function of the left kidney provided the principal tributaries, in particular, the gonadal and adrenal veins are preserved, so that renal venous blood may drain through these tributaries.12 Riccen and Dichen11 in 1942 described a patient who developed a false aneurysm of the abdominal aorta following blunt trauma by the butt of a gun. He died 27 years later when the aneurysm ruptured. In 1966, Griffen and associates5 reported the first successful surgical repair of a false aneurysm of the abdominal aorta in a
Ann. Surg.- July 1975 SETHI, SCOTT AND TAKARO sociated with Sudden Occlusion of Abdominal Aorta due to 13-year-old boy. This report adds another case of surgiBlunt Surgery, 118:125, 1975. cally repaired false aneurysm of the abdominal aorta 8. Ngu, V. Trauma. A. and Konstam, P. G.: Traumatic Dissecting Aneurysm which developed following a nonpenetrating abdominal of the Abdominal Aorta. Br. J. Surg., 52:981, 1965. 9. Parmley, L. F., Maltingly, T. W., Manion, W. C. and Jahnke, E. J.: trauma. Nonpenetrating Traumatic Injury of the Aorta. Circulation, 17:1086, 1958. References 10. Perry, M. O., Thal, E. R. and Shires, G. T.: The Management of Arterial Injuries. Ann. Surg., 173:403, 1971. 1. Beall, A. C., Jr., Arbegast, M. R., Ripepi, A. C., et al.: Aortic Laceration due to Rapid Deceleration. Arch. Surg., 98:595, 1969. 11. Ricen, E. and Dickens, P. F., Jr.: Traumatic Aneurysm of the Abdominal Aorta for 27 Years Duration. U. S. Naval Med. Bull., 2. Blute, R. and Ray, F.: Traumatic Dissecting Aneurysm of the 40:692, 1942. Abdominal Aorta. J. Maine Med. Assn., 64:164, 1973. 12. Simeone, F. A. and Hopkins, R. W.: Porta-Renal Shunt for Hepatic 3. Campbell, D. K. and Austin, R. F.: Seat Belt Injury: Injury of the Cirrhosis and Portal Hypertension. Surgery, 61:153, 1967. Abdominal Aorta. Radiology, 92:123, 1969. 13. Sinclair, T. L. and Stephenson, H. E., Jr.: Survival following Abdominal Aortic Rupture from Blunt Brauma. Missouri Med., 4. Drapanas, T. H., Hewitt, R. L., Weichert, R. F., et al.: Civilian 69:271, 1972. Vascular Injuries: A Critical Appraisal of Three Decades of 14. Susens, G. P., Hendrickson, C. G., Mulder, M. J. and Sams, B.: Management. Ann. Surg., 172:351, 1970. Femoral Nerve Entrapment Secondary to Heparin Hematoma. 5. Griffen, W. O., Belin, R. P. and Walder, A. I.: Traumatic Ann. Intern. Med., 69:575, 1968. Aneurysm of the Abdominal Aorta. Surgery, 60:813, 1966. 15. Strassmann, G.: Traumatic Rupture of the Aorta. Am. Heart J., 6. Killen, D. A.: Injuries of the Superior Mesenteric Vessels Secon33:508, 1947. dary to Nonpenetrating Abdominal Trauma. Am. Surg., 30:306, 16. Welborn, M. B. and Sawyers, J. L.: Acute Abdominal Aortic 1964. Occlusion due to Nonpenetrating Trauma. Am. J. Surg., 7. Mozingo, J. R. and Denton, I. C.: The Neurological Deficit As118:112, 1969.