Abdominal Vascular Injury

Christopher J. Dente and David V. Feliciano

The major sites of hemorrhage in patients sustaining blunt or penetrating abdominal trauma are the viscera, the mesentery, and the major abdominal vessels. The term abdominal vascular injury generally refers to injury to major intraperitoneal or retroperitoneal vessels and is generally classified into four zones described as follows and in Table 34-1:

TABLE 34-1 Classification of Abdominal Vascular Injury

• Zone 1: midline retroperitoneum

Supramesocolic region

Inframesocolic region

• Zone 2: upper lateral retroperitoneum

• Zone 3: pelvic retroperitoneum

• Porta hepatis/retrohepatic inferior vena cava

As many of these vessels are somewhat difficult to quickly access via a midline laparotomy incision, a systematic operative approach is required to adequately diagnose and manage these potentially devastating injuries. A general discussion of epidemiology and methods of diagnosis, with subsequent descriptions of the operative management of abdominal vascular injuries within each region of the abdomen, follows.

EPIDEMIOLOGY

In reviews of vascular injuries sustained in military conflicts, abdominal vascular injuries have been extraordinarily rare. For example, DeBakey and Simeone’s classic article on 2,471 arterial injuries during World War II included only 49 that occurred in the abdomen, an incidence of 2%.¹ Reporting on 304 arterial injuries from the Korean conflict, Hughes noted that only 7, or 2.3%, occurred in the iliac arteries.² In the review by Rich et al. of 1,000 arterial injuries in the Vietnam War, only 29, or 2.9%, involved abdominal vessels.³ Finally, a recent review of abdominal injuries during the Iraqi conflict documented only 4 injuries to major vessels in 145 patients undergoing laparotomy (2.8%).⁴

The data from civilian trauma centers are quite different. In 1979, 15% of patients with abdominal trauma treated at the Ben Taub General Hospital in Houston had injuries to major vascular structures.⁵ Also, abdominal vascular injury accounted for 27.5% of all arterial injuries treated over that same time period. A similar review from the same hospital in 1982 revealed that 31.9% of all vascular injuries occurred in the abdomen, including 18.5% of all arterial injuries and 47.5% of all venous injuries.⁶ Finally, a 30-year review (1958–1988) at the same hospital, published in 1989, documented that 33.8% of 5,760 cardiovascular injuries occurred in the abdomen.⁷ In the last 5 years of the period covered by the report (1984–1988), abdominal vascular injuries accounted for 27.3% of all cardiovascular injuries.

Even with the recent decrease in the volume of penetrating trauma in some centers, many patients with abdominal vascular injuries continue to be treated. For example, there were 302 patients with 238 abdominal arterial and 266 abdominal venous injuries who underwent operative repair at the Los Angeles County Hospital (University of Southern California) from 1992 to 1997.⁸ Similarly, there were 300 patients with 205 abdominal arterial and 284 abdominal venous injuries who underwent operative repair at the Grady Memorial Hospital (Emory University) from 1989 to 1998.⁹

The significantly higher number of abdominal vascular injuries treated in civilian as opposed to military practice likely reflects the modest wounding capacity of many handguns when compared with military ordinance, as well as the shorter prehospital transit times in most urban areas of the United States. Advances in military armor and the changing tactics of modern warfare also have led to a shift in injuries to the extremities rather than the torso, although noncompressible (torso) hemorrhage remained the leading cause of combatant death from hemorrhage in a recent review.¹⁰

At present, the estimated incidence of injury to major abdominal vessels in patients sustaining blunt abdominal trauma is thought to be about 5–10%.^11,12 This is compared with patients with penetrating stab wounds to the abdomen, who will sustain a major abdominal vascular injury approximately 10% of the time (V. Spjut-Patrinely, D. V. Feliciano, Data from Ben Taub General Hospital, Houston, Texas, July 1985 to June 1988, unpublished), and patients with gunshot wounds to the abdomen, who will have injury to a major vessel 20–25% of the time.¹³

PATHOPHYSIOLOGY

Blunt Trauma

Rapid deceleration in motor vehicle crashes may cause two different types of vascular injuries in the abdomen. The first is avulsion of small branches from major vessels, with subsequent hemorrhage. A common example of this is the avulsion of intestinal branches from either the proximal or distal superior mesenteric artery at sites of fixation. A second type of vascular problem seen with deceleration injury is an intimal tear with secondary thrombosis of the lumen, such as is seen in patients with renal artery thrombosis, or a full-thickness tear with a secondary pseudoaneurysm of the renal artery.^14–16

Crush injuries to the abdomen, such as by a lap seat belt or by a posterior blow to the spine, also may cause two different types of vascular injury. The first is an intimal tear or flap with secondary thrombosis of a vessel such as the superior mesenteric artery,¹⁷ infrarenal abdominal aorta,^18,19 or iliac artery.^20,21 The “seat belt aorta” is a classic example of an injury resulting from this mechanism.^18,22 Direct blows can also completely disrupt exposed vessels, such as the left renal vein over the aorta²³ or the superior mesenteric artery or vein at the base of the mesentery,²⁴ leading to massive intraperitoneal hemorrhage, or even partly disrupt the infrarenal abdominal aorta, leading to a false aneurysm.^25,26

Penetrating Trauma

Penetrating injuries, in contrast, create the same kinds of abdominal vascular injuries as are seen in the vessels of the extremities, producing blast effects with intimal flaps and secondary thrombosis, lateral wall defects with hemorrhage or pulsatile hematomas (early false aneurysms), or complete transection with either free bleeding or thrombosis.²⁷ On rare occasions, a penetrating injury may produce an arteriovenous fistula involving the portal vein and hepatic artery, renal vessels, or iliac vessels.

Iatrogenic injuries to major abdominal vessels are an uncommon but persistent problem. Reported iatrogenic causes of abdominal vascular injury have included diagnostic procedures (angiography, cardiac catheterization, laparoscopy), abdominal operations (pelvic and retroperitoneal procedures), spinal operations (removal of a herniated disk), and adjuncts to cardiac surgery (cardiopulmonary bypass, intra-aortic balloon assist).^28–30

DIAGNOSIS

History and Physical Examination

An abdominal vascular injury may present in one of three ways including free intraperitoneal hemorrhage, a contained intraperitoneal or retroperitoneal hematoma, and thrombosis of the vessel. As such, patients can be quickly divided into two major groups including those with ongoing hemorrhage and those without ongoing hemorrhage (contained hematoma or thrombosis). The presenting symptoms, thus, are variable based on both the event and the involved vessel. After blunt trauma, for example, free intraperitoneal hemorrhage may be seen with avulsion of mesenteric vessels and lead to secondary hypovolemic shock. Conversely, when thrombosis of the renal artery is present, the patient will be hemodynamically stable but may complain of upper abdominal and flank pain and will commonly have hematuria (70–80%).¹⁶ Thrombosis of the proximal superior mesenteric artery will cause severe abdominal pain, while thrombosis of the infrarenal abdominal aorta will cause pulseless lower extremities.

Penetrating truncal wounds between the nipples and the upper thighs remain the most common cause of abdominal vascular injuries. The exact vessel injured is generally related to the track of the missile or stab wound. For example, gunshot wounds directly on the midline most commonly involve the inferior vena cava or abdominal aorta. Gunshot wounds traversing the pelvis will often injure branches of the iliac artery or vein, while gunshot wounds in the right upper quadrant may involve the renovascular structures, vascular structures within the porta hepatis, or the retrohepatic inferior vena cava.

On physical examination, the findings in patients with abdominal vascular injury will obviously depend on whether a contained hematoma or active hemorrhage is present. Patients with contained hematomas in the retroperitoneum, base of the mesentery, or hepatoduodenal ligament, particularly those with injuries to abdominal veins, may be hypotensive in transit but often respond rapidly to the infusion of fluids. They may remain remarkably stable, with modest or even no peritoneal signs on examination, until the hematoma is opened at the time of laparotomy. These patients are candidates for the imaging studies mentioned below. Conversely, patients with active hemorrhage generally have a rigid abdomen and unrelenting hypotension. These patients should obviously undergo immediate laparotomy without further evaluation. In a review by Ingram et al. of 70 consecutive patients undergoing laparotomy for an abdominal vascular injury, patients could generally be divided into two groups based on an admission systolic blood pressure greater than or less than 100 mm Hg.³¹ In the former group, the mean base deficit on admission was −7.2, blood replacement in the operating room was 8.6 U, an isolated venous injury was present in 73.1% of patients, and survival was 96.2%. This was compared with a 43% survival and an average of 15.1 U of blood replacement in patients presenting with hypotension (Table 34-2). Indeed, admission base deficit was the only independent indicator of mortality in a recent series of patients with abdominal vascular injuries from Lincoln Hospital in New York City.³²

TABLE 34-2 Blood Pressure in the Emergency Department in Patients with Abdominal Vascular Injury

The other major physical finding that may be noted in patients with abdominal vascular injury is loss of the pulse in the femoral artery in one lower extremity when the ipsilateral common or external iliac artery has been transected or is thrombosed. In such patients, the presence of a transpelvic gunshot wound associated with a wavering or an absent pulse in the femoral artery is pathognomonic of injury to the ipsilateral iliac artery.

Imaging

In both stable and unstable patients, a rapid surgeon-performed ultrasound (Focused Assessment for the Sonographic Evaluation of the Trauma Patient [“FAST”]) is useful in ruling out an associated cardiac injury with secondary tamponade or an associated hemothorax mandating the insertion of a thoracostomy tube.^33–36 In a stable patient with an abdominal gunshot wound, a routine flat-plate x-ray of the abdomen is of diagnostic value, so that the track of the missile can be predicted from markers placed over the wounds or from the position of a retained missile.

In former years, all patients who had suffered penetrating abdominal wounds and who were not in shock would undergo a one-shot intravenous pyelogram (IVP) in the emergency department. The major purposes of this study were as follows: to evaluate the function of both kidneys, with lack of flow to one kidney suggesting either absence of the kidney or thrombosis of the renal artery; the presence of active hemorrhage from the kidney itself; and the position and status of the ureters. This study is no longer performed routinely and is indicated only in stable patients with a flank wound and gross hematuria when the computed tomography (CT) scanner is not available.

In patients with blunt abdominal trauma, hematuria, modest to moderate hypotension, and peritonitis in the emergency department, a preoperative one-shot IVP during resuscitation would still be useful for documenting the presence of an intact kidney. If the kidney is mostly intact without extravasation of the dye, the surgeon will not have to open a perirenal hematoma at the subsequent laparotomy. Nonvisualization of one kidney on the IVP, suggesting thrombosis of the renal artery, was evaluated by renal arteriography in stable patients in the past. Experience with CT scanning of the abdomen in multiple patients with blunt trauma has documented that the absence of renal enhancement and excretion and the presence of a cortical rim sign are diagnostic of thrombosis of the renal artery, and arteriography is no longer indicated for this diagnosis.³⁷ Similarly, any stable patient with blunt trauma who does not require an immediate laparotomy and who has significant hematuria should undergo an immediate abdominal CT scan without a preliminary one-shot IVP.³⁸

Preoperative abdominal aortography should not be routinely performed to document intra-abdominal vascular injuries after penetrating wounds. This is because most patients with such wounds are not stable enough to undergo the manipulation required for appropriate studies of large vessels in an angiographic suite. In patients with blunt trauma, aortography is used to diagnose and treat deep pelvic arterial bleeding associated with fractures³⁹ and to diagnose unusual injuries such as the previously mentioned intimal tears with thrombosis in the infrarenal aorta, the iliac artery, or the renal artery. The occasional patient is also a candidate for endovascular therapy and this will be discussed below.

As the technology of CT scanning has advanced, many surgeons and radiologists are comfortable making therapeutic decisions based on data acquired from multiplanar scanning and formal CT angiography. Extensive literature exists on the diagnosis of traumatic thoracic aortic disruption with CT⁴⁰ and at least one small prospective study has shown acceptable accuracy of CT angiography in extremity trauma.⁴¹ Conversely, data on the use of CT angiography as a method of diagnosis of abdominal vascular injury remain preliminary. Indeed, in one recent study, contrast-enhanced CT alone had a 94% sensitivity and 89% specificity for the diagnosis of active hemorrhage when compared with angiography.⁴² Most of the positive scans involved branches of the internal iliac artery with a concomitant pelvic fracture or injuries to solid organs and, thus, were not necessarily diagnostic of true abdominal vascular injury. Still, in the stable patient with blunt trauma, findings on CT that are suggestive of injury to the retroperitoneal great vessels warrant further evaluation with angiography or operative intervention.

INITIAL MANAGEMENT AND RESUSCITATION

Prehospital Resuscitation

Resuscitation in the field in patients with possible blunt or penetrating abdominal vascular injuries should be restricted to basic airway maneuvers such as intubation or cricothyroidotomy and decompression of a tension pneumothorax at the scene. Insertion of intravenous lines for infusing crystalloid solutions is best attempted during transport to the hospital. Restoration of blood pressure to normal levels is critical to neurologic recovery in the rare patients with associated blunt intracranial injuries and possible abdominal vascular injuries.⁴³ In contrast, there is no consistent evidence to support either the aggressive administration of crystalloid solutions during the short prehospital times in urban environments or the withholding of similar solutions (“delayed resuscitation”) in patients with penetrating abdominal vascular injuries.^44,45 Indeed, a key component of “damage control resuscitation” as espoused by the US military and discussed below is minimization of early crystalloid resuscitation.⁴⁶

Emergency Department Resuscitation

In the emergency department, the extent of resuscitation clearly depends on the patient’s condition at the time of arrival. In the agonal patient with a rigid abdomen after a gunshot wound, emergency department thoracotomy with cross-clamping of the descending thoracic aorta may be necessary to maintain cerebral and coronary arterial flow, especially if the trauma operating room is geographically distant from the emergency department.⁴⁷ Although all trauma surgeons agree that performing a thoracotomy in the emergency department will complicate the patient’s intraoperative course, the thoracotomy and cross-clamping are sometimes the only way to prevent irreversible ischemic changes in the patient’s brain and heart until a laparotomy with vascular control can be performed. It must be recognized, however, that the need for emergency department thoracotomy is essentially predictive of a <5% survival for the patient with blunt or penetrating abdominal trauma.⁴⁸ In the large series by Feliciano et al.,⁴⁷ only 1 of 59 patients with isolated penetrating wounds to the abdomen survived after undergoing a preliminary thoracotomy in the emergency department.

In the patient arriving with blunt abdominal trauma, hypotension, and a positive surgeon-performed “FAST” or penetrating abdominal trauma and hypotension or peritonitis, a time limit of less than 5 minutes in the emergency department is mandatory. An identification bracelet is applied, an airway and thoracostomy tube are inserted if necessary, especially if the operating room is geographically distant, and blood samples for typing and cross-matching are obtained with the insertion of the first intravenous catheter. Whether more intravenous lines should be inserted in the emergency department or after arrival in the operating room is much debated. The authors have always believed that patients needing an emergency laparotomy should be in the operating room, as soon as the identification bracelet has been applied and a blood specimen has been sent to the blood bank.

There are now multiple large-bore catheters, specialized administration sets, and heating elements commercially available for use in the emergency department or operating room. With short, large-bore (10-gauge or number 8.5 French) catheters in peripheral veins, flow rates of 1,400–1,600 mL/min of crystalloid solutions can be obtained when an external pressure device is exerting 300 mm Hg pressure.⁴⁹ Blood replacement during resuscitation is usually with type-specific blood, although universal donor type O negative blood may be used when there is no time for even a limited cross-match.

Measures in the emergency department that will diminish the hypothermia of resuscitation include the following: a heated resuscitation room, the use of prewarmed (37–40°C [98.6–104.0°F]) crystalloid solutions, passage of all crystalloids and blood through high-flow warmers, and covering the patient’s trunk and extremities with prewarmed blankets or heating units.^48–50

Damage Control Resuscitation and Massive Transfusion

In the last 5 years, based mostly on the military experience in Iraq, there has been a dramatic change in the resuscitation philosophy of critically injured patients in many centers. The military resuscitation philosophy of “damage control resuscitation” is seen as an extension of the concepts of “damage control surgery,” a term coined in the early 1990s by Rotondo et al.⁵¹ One cornerstone of damage control resuscitation is the early and aggressive use of either fresh whole blood or blood components (fresh frozen plasma and platelets) in high, defined ratios to packed red blood cells. In the civilian setting, this practice requires the support of the blood bank and a highly organized massive transfusion protocol (MTP). Multiple civilian centers have now published their results using institution-specific MTPs, generally with significant improvements in patient outcome.^52–55 As many patients with abdominal vascular injury will require massive transfusion, the treating surgeons should be familiar with the design and implementation of any MTP that exists in their institution. The concepts of damage control surgery, damage control resuscitation, and massive transfusion will be covered in much more detail elsewhere in this text.

OPERATIVE PREPERATIONS

Draping and Incisions

In the operating room, the entire trunk from the chin to the knees is prepared and draped in the usual manner. Before making the incision for laparotomy, the trauma surgeon should confirm that the following items are available: blood components for transfusion, autotransfusion apparatus, a thoracotomy tray, an aortic compressor, a complete tray of vascular instruments, sponge sticks with gauze sponges in place for venous compression, as well as appropriate vascular sutures.

Maneuvers to Prevent or Decrease Hypothermia

In addition to the maneuvers previously described for preventing hypothermia in the emergency department, operative maneuvers with the same purpose include warming the operating room to >85°F (29.4°C); covering the patient’s head; covering the upper and lower extremities with a heating unit (Bair Hugger, Augustine Medical, Inc, Eden Prairie, Minnesota); the irrigation of nasogastric tubes, thoracostomy tubes, and open body cavities with warm saline; and the use of a heating cascade on the anesthesia machine.⁵⁶

General Principles

A preliminary operating room thoracotomy with cross-clamping of the descending thoracic aorta is used in some centers when the patient’s blood pressure on arrival is less than 70 mm Hg.^57–59 As previously mentioned, this maneuver will maintain cerebral and coronary arterial flow if the heart is still beating and may prevent sudden cardiac arrest when abdominal tamponade is released. Unfortunately, it has little effect on intra-abdominal vascular injuries because of persistent bleeding from backflow. Indeed, patients with unrelenting shock after cross-clamping of the descending thoracic aorta essentially never survive.⁵⁹

A midline abdominal incision is made, and all clots and free blood are manually evacuated or removed with suction. A rapid inspection is performed to visualize contained hematomas or areas of hemorrhage. One intra-abdominal physical finding that may be of diagnostic benefit to the surgeon is “black bowel,” which has been seen in patients with total transection or thrombosis of the proximal superior mesenteric artery. In a patient with a penetrating upper abdominal wound, a large hematoma in the supramesocolic area, and black bowel, an injury to the superior mesenteric artery is likely to be present.⁶⁰

Active hemorrhage from solid organs is controlled by packing, while standard techniques of vascular control are used to control the active hemorrhage from major intra-abdominal vessels. Finger pressure, compression with laparotomy pads, grabbing the perforated artery with a hand (common or external iliac artery), or formal proximal and distal control is needed to control any actively hemorrhaging major artery. Similarly, options for control of bleeding from major veins such as the inferior vena cava, superior mesenteric vein, renal veins, or iliac veins include finger pressure, compression with laparotomy pads or sponge sticks, grabbing the perforated vein with a hand, applying Judd-Allis clamps to the edges of the perforation,⁶¹ and the application of vascular clamps. Once hemorrhage from the vascular injuries is controlled in patients with penetrating wounds, it may be worthwhile to rapidly apply Babcock clamps, Allis clamps, or noncrushing intestinal clamps, or to rapidly use a surgical stapler to control as many gastrointestinal perforations as possible to avoid further contamination of the abdomen during the period of vascular repair. The abdomen is irrigated with an antibiotic–saline solution, the vascular repair is then performed, a soft tissue cover is applied over the repair, and the remainder of the operation is directed toward repair of injuries to the bowel and solid organs.

Conversely, if the patient has a contained retroperitoneal hematoma at the time of laparotomy, the surgeon occasionally has time to first perform necessary gastrointestinal repairs in the free peritoneal cavity, change gloves, and irrigate with an antibiotic–saline solution. The surgeon can then open the retroperitoneum to expose the underlying abdominal vascular injury.

Hematomas or hemorrhage associated with abdominal vascular injuries generally occur in zone 1, midline retroperitoneum; zone 2, upper lateral retroperitoneum; zone 3, pelvic retroperitoneum; or the portal–retrohepatic area of the right upper quadrant, as previously described (Table 34-1). The magnitude of injury is best described using the Organ Injury Scale of the American Association for the Surgery of Trauma (AAST).⁶²

MANAGEMENT OF INJURIES IN ZONE 1: SUPRAMESOCOLIC REGION

Exposure and Vascular Control

The midline retroperitoneum of zone 1 is divided by the transverse mesocolon into a supramesocolic region and an inframesocolic region. If a hematoma or hemorrhage is present in the midline supramesocolic area, injury to the suprarenal aorta, celiac axis, proximal superior mesenteric artery, or proximal renal artery should be suspected. In such cases, there are several techniques for obtaining proximal vascular control of the aorta at the hiatus of the diaphragm. When a contained hematoma is present, as it frequently is with wounds to the aorta in the aortic hiatus, the surgeon usually has time to reflect all left-sided intra-abdominal viscera, including the colon, kidney, spleen, tail of the pancreas, and fundus of the stomach to the midline (left-sided medial visceral rotation) (Fig. 34-1).^63–66 The advantage of this technique is that it provides extensive exposure for visualization of the entire abdominal aorta from the aortic hiatus of the diaphragm to the aortic bifurcation. Disadvantages include the time required to complete the maneuver (5–7 minutes), risk of damage to the spleen, left kidney, or posterior left renal artery during the maneuver, and a fold in the aorta that results when the left kidney is rotated anteriorly. One alternative is to leave the left kidney in its fossa, thereby eliminating potential damage to or distortion resulting from rotation of this structure. In either case, this maneuver provided the best exposure and allowed for the greatest survival in a series of 46 patients with suprarenal aortic injuries studied at Ben Taub General Hospital in Houston, Texas, in the 1970s.⁶⁵

FIGURE 34-1 Left medial visceral mobilization is performed in the retroperitoneal plane behind all left-sided intra-abdominal viscera in a patient with a supramesocolic hematoma in the midline. (Reproduced with permission from Feliciano DV. Truncal vascular trauma. In: Callow AD, Ernst CB, eds. Vascular Surgery. Theory and Practice. Stamford, CT: Appleton & Lange; 1995:1059–1085. © The McGraw-Hill Companies, Inc.)

Because of the dense nature of the celiac plexus of nerves connecting the right and left celiac ganglia as well as the lymphatics that surround the supraceliac aorta, it is frequently helpful to transect the left crus of the aortic hiatus of the diaphragm at the 2 o’clock position to allow for exposure of the distal descending thoracic aorta above the hiatus.⁶⁷ With the distal descending thoracic aorta in the hiatus exposed, a supraceliac aortic clamp can be applied without difficulty. This allows for the extra few centimeters of exposure that is essential for complex repair of the vessels within this tightly confined anatomic area.

Conversely, if active hemorrhage is coming from this area, the surgeon may attempt to control it manually or with one of the aortic compression devices.^68,69 Failing this, an alternate approach is to divide the lesser omentum manually, retract the stomach and esophagus to the left, and digitally separate the muscle fibers of the aortic hiatus of the diaphragm from the supraceliac aorta to obtain similar, if not more, limited exposure as described for the left-sided medial visceral rotation, but more quickly.⁷⁰ After either approach to the suprarenal abdominal aorta, cross-clamp time should be minimized to avoid the primary fibrinolytic state that occurs, presumably due to hepatic hypoperfusion.⁷¹ Distal control of the aorta in this location is awkward because of the presence of the celiac axis and superior mesenteric artery (Fig. 34-2). In some patients with injury confined to the supraceliac aorta, the celiac axis may have to be divided and ligated to allow for more space for the distal aortic clamp and subsequent vascular repair. Necrosis of the gallbladder is a likely sequela, and cholecystectomy is generally warranted, although this may be done at repeat exploration when “damage control” techniques are required.⁷²

FIGURE 34-2 (A) View of suprarenal aorta and major branches after left-sided medial mobilization maneuver. (B) Diagrammatic representation of structures with labels. (Reproduced with permission from Baylor College of Medicine.)

Suprarenal Aorta

With small perforating wounds to the aorta at this level, lateral aortorrhaphy with 3-0 or 4-0 polypropylene suture is preferred. If two small perforations are adjacent to one another, they should be connected and the defect closed in a transverse fashion with the polypropylene suture. When closure of the perforations results in significant narrowing, or if a portion of the aortic wall is missing, patch aortoplasty with polytetrafluoroethylene (PTFE) is indicated. The other option is to resect a short segment of the injured aorta and attempt to perform an end-to-end anastomosis. Unfortunately, this is often impossible because of the limited mobility of both ends of the aorta at this level.

On rare occasions, patients with extensive injuries to the diaphragmatic or supraceliac aorta will require insertion of a synthetic vascular conduit or spiral graft after resection of the area of injury.^73–75 Many of these patients have associated gastric, enteric, or colonic injuries, and much concern has been expressed about placing a synthetic conduit, such as a 12-, 14-, or 16-mm woven Dacron, albumin-coated Dacron, or PTFE prosthesis, in the abdominal aorta (Fig. 34-3). The data in the American literature describing young patients with injuries to nondiseased abdominal aortas do not support the concern about Dacron interposition grafts, and there are few reports describing the use of PTFE grafts in penetrating trauma to the abdominal aorta. Despite the available data, some clinicians continue to recommend an extra-anatomic bypass when injury to the abdominal aorta would require replacement with a conduit in the presence of gastrointestinal contamination.²²

FIGURE 34-3 A 22-year-old man with a gunshot wound to the right upper quadrant had injuries to the prepyloric area of the stomach and to the supraceliac abdominal aorta. The aortic injury was managed by segmental resection and replacement with a 16-mm polytetrafluoroethylene (PTFE) graft. The patient was discharged 46 days after injury. (Reproduced with permission from Feliciano DV. Injuries to the great vessels of the abdomen. In: Holcroft JW, ed. Scientific American Surgery. Trauma Section. New York: Scientific American; 1998:1–12.)

As previously noted, repairs of the intestine and the aorta should not be performed simultaneously. Once the perforated bowel has been packed away and the surgeon has changed gloves, the aortic prosthesis is sewn in place with 3-0 or 4-0 polypropylene suture. After appropriate flushing of both ends of the aorta and removal of the distal aortic clamp, the proximal aortic clamp should be removed very slowly as the anesthesiologist rapidly infuses fluids. If a long aortic clamp time has been necessary, the prophylactic administration of intravenous bicarbonate is indicated to reverse the “washout” acidosis from the previously ischemic lower extremities.⁷⁶ The retroperitoneum is then copiously irrigated and closed in a watertight fashion with an absorbable suture.

Cross-clamping of the supraceliac aorta in a patient with hemorrhagic shock results in severe ischemia of the lower extremities. Restoration of arterial inflow will then cause a reperfusion injury. In a patient who is hemodynamically stable after repair of the suprarenal (or infrarenal) abdominal aorta, measurement of compartmental pressures below the knees should be performed before the patient is moved from the operating room. Pressures in the range of 30–35 mm Hg should be treated with below-knee, two-incision, four-compartment fasciotomies.⁷⁷

The survival rate of patients with penetrating injuries to the suprarenal abdominal aorta in eight series published from 1974 to 1992 was 34.8%^{65,75,78–83} (Table 34-3). Four more recent reviews have documented a significant decline in survival for injuries to the abdominal aorta (suprarenal and infrarenal), ranging from 21.1% to 50% (mean 30.2%) even when patients with exsanguination before repair or those treated with ligation only were excluded.^8,9,84,85 In one series in which injuries to the suprarenal and infrarenal abdominal aorta were separated, the survival rate in the suprarenal group was only 8.3% (3/36).⁸⁴ The reasons for this decrease in survival figures are not defined in the reviews described, although a likely cause is the shorter prehospital times for exsanguinated patients that have been realized with improvements in emergency medical services.

TABLE 34-3 Survival with Injuries to the Abdominal Aorta

Blunt injury to the suprarenal aorta is extraordinarily rare. While blunt injury to the descending thoracic aorta is well described throughout the trauma literature, only 62 cases of blunt trauma to the abdominal aorta were found by Roth et al. in a literature review in 1997.²² Of these, only one case was noted to be in the suprarenal aorta. The most common location is between the origin of the inferior mesenteric artery and the aortic bifurcation (see below). These injuries generally present with signs and symptoms of aortic thrombosis, rather than hemorrhage, with the most common signs being a lack of femoral pulses (81%), abdominal tenderness (55%), lower extremity weakness or paralysis (47%), and paresthesias (20%).²² Management of these injuries is discussed more extensively in Section “Infrarenal Aorta.”

Celiac Axis

Injury to the celiac axis is rare. One of the largest series in the literature, reported by Asensio et al., documented the treatment of 13 patients with this uncommon injury.⁸⁶ Penetrating injuries were the cause in 12 patients, and overall mortality was 62%. Eleven patients were treated with ligation and one with primary repair, with the final patient exsanguinating prior to therapy. Of the five survivors, four had undergone ligation, and all deaths occurred in the operating room. This group also performed an extensive literature review and could only document 33 previously reported cases, all the result of penetrating trauma. Furthermore, they could find no survivor treated with any sort of complex repair.⁸⁶ One case of injury to the celiac artery after blunt trauma was reported by Schreiber et al. and occurred in a patient with preexisting median arcuate ligament syndrome.⁸⁷ Given these results, patients with injuries to the celiac axis that are not amenable to simple arteriorrhaphy should undergo ligation, which should not cause any short-term morbidity other than the aforementioned risk of gallbladder necrosis.

When branches of the celiac axis are injured, they are often difficult to repair because of the dense neural and lymphatic tissue in this area and the small size of the vessels in a patient in shock with secondary vasoconstriction. There is clearly no good reason to fix major injuries to either the left gastric or proximal splenic artery in the patient with trauma to this area. In both instances, these vessels should be ligated. The common hepatic artery may have a larger diameter than the other two vessels, and an injury to this vessel may occasionally be amenable to lateral arteriorrhaphy, end-to-end anastomosis, or the insertion of a saphenous vein or prosthetic graft. In general, however, one should not worry about ligating the hepatic artery proper proximal to the origin of the gastroduodenal artery, since the extensive collateral flow from the midgut through this vessel will maintain the viability of the liver.

Superior Mesenteric Artery

Injuries to the superior mesenteric artery are managed based on the level of injury. In 1972, Fullen et al.⁸⁸ described an anatomic classification of injuries to the superior mesenteric artery that has been used intermittently by subsequent authors in the trauma literature.^60,89 If the injury to the superior mesenteric artery is beneath the pancreas (Fullen zone 1), the pancreas may have to be transected between Glassman and Dennis intestinal clamps to control the bleeding point. Because the superior mesenteric artery has few branches at this level, proximal and distal vascular control is relatively easy to obtain once the overlying pancreas has been divided. Another option is to perform medial rotation of the left-sided intra-abdominal viscera, as previously described, and apply a clamp directly to the proximal superior mesenteric artery at its origin from the left side of the aorta. In this instance, the left kidney may be left in the retroperitoneum as the medial rotation is performed.

Injuries to the superior mesenteric artery also occur beyond the pancreas at the base of the transverse mesocolon (Fullen zone 2, between the pancreaticoduodenal and middle colic branches of the artery). Although there is certainly more space in which to work in this area, the proximity of the pancreas and the potential for pancreatic leaks near the arterial repair make injuries in this location almost as difficult to handle as the more proximal injuries.^60,88,89 If the superior mesenteric artery has to be ligated at its origin from the aorta or beyond the pancreas (Fullen zone 1 or 2), collateral flow from both the foregut and hindgut should maintain theoretically the viability of the midgut in the distribution of this vessel.⁹⁰ In truth, however, exsanguinating hemorrhage from injuries in this area often leads to intense vasoconstriction of the more distal superior mesenteric artery. For this reason, collateral flow is often inadequate to maintain viability of the distal midgut, especially the cecum and ascending colon. In the hemodynamically unstable patient with hypothermia, acidosis, and a coagulopathy, the insertion of a temporary intraluminal shunt into the debrided ends of the superior mesenteric artery is most appropriate and fits the definition of damage control.⁹¹ If replacement of the proximal superior mesenteric artery is necessary in a more stable patient, it is safest to place the origin of the saphenous vein or prosthetic graft on the distal infrarenal aorta, away from the pancreas and other upper abdominal injuries (Fig. 34-4).⁶⁰ A graft in this location should be tailored so that it will pass through the posterior aspect of the mesentery of the small bowel and then be sutured to the superior mesenteric artery in an end-to-side fashion without significant tension. It is mandatory to cover the aortic suture line with retroperitoneal fat or a viable omental pedicle to avoid an aortoduodenal or aortoenteric fistula at a later time. This is much easier to perform if the proximal origin of the graft is located on the distal aorta. Injuries to the more distal superior mesenteric artery (Fullen zone 3, beyond the middle colic branch, and zone 4, at the level of the enteric branches) should be repaired, since ligation in this area is distal to the connection to collateral vessels from the foregut and the hindgut.⁹² This may require microsurgical techniques.⁹³ If this cannot be accomplished because of the small size of the vessel, ligation may mandate extensive resection of the ileum and right colon.

FIGURE 34-4 (A) When complex grafting procedures to the superior mesenteric artery are necessary, it may be dangerous to place the proximal suture line near an associated pancreatic injury. (B) The proximal suture line should be on the lower aorta, away from the upper abdominal injuries, and should be covered with retroperitoneal tissue. (Reproduced from Accola KD, Feliciano DV, Mattox KL, et al. Management of injuries to the superior mesenteric artery. J Trauma. 1986;26:313.)

The survival rate of patients with penetrating injuries to the superior mesenteric artery in six series published from 1972 to 1986 was 57.7% (Table 34-4).^{60,81,86,94–96} Four more recent reviews, including a large multi-institutional study,⁸⁹ had a mean survival of 58.7%.^8,9,84,89 In one of the older series, survival decreased to 22% when any form of repair more complex than lateral arteriorrhaphy was performed.⁶⁰ Independent risk factors for mortality in the multi-institutional study included injury to Fullen zone 1 or 2, transfusion of >10 U of packed red blood cells, intraoperative acidosis or dysrhythmias, and multisystem organ failure.⁸⁹

TABLE 34-4 Survival with Injuries to the Superior Mesentery Artery

Proximal Renal Arteries

Injuries to the proximal renal arteries may also present with a zone 1, supramesocolic hematoma or with hemorrhage in this area. The left medial visceral rotation maneuver described earlier allows visualization of much of the posterior left renal artery from the aorta to the kidney. This maneuver does not, however, allow for visualization of the proximal right renal artery. The proximal vessel is best approached through the base of the mesocolon beneath the left renal vein and between the infrarenal abdominal aorta and inferior vena cava. Options for repair of either the proximal or distal renal arteries are described later in this chapter (Section “Management of Injuries in Zone 2”).

Superior Mesenteric Vein

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