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 (diaphragmatic aorta), 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). This maneuver was originally described by DeBakey et al,72 applied by Elkins et al,73 and modified by Mattox et al (Fig. 34-1).74 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.75 Disadvantages include the time required to complete the maneuver (5–7 minutes), risk of injury 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.76 One alternative is to leave the left kidney in its fossa, thereby eliminating potential damage to or decreasing renal blood flow 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.74
Completion of left medial visceral mobilization after elevation of left colon, left kidney, spleen, tail of the pancreas, and fundus of the stomach.
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 superior to the hiatus.76 With the distal descending thoracic aorta in the hiatus exposed, a supraceliac aortic clamp such as a Crafoord—DeBakey or Cherry can be applied. 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 identified from this area, the surgeon may attempt to control it manually or with one of the aortic compression devices such as the Conn-Trippel aortic root compessor.77,78 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 exposure as described for the left-sided medial visceral rotation, but more quickly.79 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.80 Similarly, the time of placement of the clamp should be noted. 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 performed at repeat exploration when “damage control” techniques are required.81
(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.)
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 by incising them with a Potts scissors and the defect closed in a transverse fashion with polypropylene sutures. 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. This, however, is rarely necessary. 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 and by the need to mobilize the lumbar arteries.
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.82,83,84 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. The data in the American literature describing young patients with injuries to nondiseased abdominal aortas do not support the concern about Dacron interposition grafts; however, 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
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. Baseline arterial blood gases may be helpful in guiding bicarbonate replacement.85 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 with its physiological consequences. 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.86 Measurement of the pressure in the anterior compartments of the thighs is worthwhile, as well.
The survival rate of patients with penetrating injuries to the suprarenal abdominal aorta in the past was 35%.87,88,89,90,91,92 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 (Table 34-2).8,9,93,94 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).93 The reasons for this decrease in survival figures are not defined in the reviews described, although the most likely cause is the shorter prehospital times secondary to improvements in emergency medical services. This brings many patients who would otherwise not survive transit to the trauma center to die in the same.
TABLE 34-2Survival with Injuries to the Abdominal Aortaa ||Download (.pdf) TABLE 34-2 Survival with Injuries to the Abdominal Aortaa
| ||Asensio et al8 ||Davis et al9 ||Tyburski et al93 ||Coimbra et al94 |
|Abdominal aorta overall ||36.1 (13/63) ||39.1% (25/64) ||21.9% (15/71) ||51% (12/24) |
|Isolated ||21.7% (10/46) ||— ||— ||— |
|With other artery ||17.6% (3/17) ||— ||— ||— |
|Suprarenal ||— ||— ||8.3% (3/36) ||— |
|Infrarenal ||— ||— ||34.2% (12/35) ||— |
Blunt injury to the suprarenal or infrarenal 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 the section “Infrarenal Aorta.”
Injury to the celiac axis is rare. In the review by Asensio et al, only 13 patients with this uncommon injury were treated.95 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 treatment. 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.95 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.96 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. The collateral circulation between the celiac axis and the superior mesenteric artery will maintain viability of the viscera in the foregut. If in doubt a “second look laparotomy” should be performed.
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 patients with profound shock with secondary vasoconstriction. There is clearly no good reason to repair 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 al97 described an anatomic classification of injuries to the superior mesenteric artery that has been used intermittently by subsequent authors in the trauma literature.69,98 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 or GIA or TA staplers to locate and control the bleeding points. 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. It is important to remember that the celiac axis and superior mesenteric artery have a “v” conformation when approached from the left side (see Fig. 34-2).
Injuries to the superior mesenteric artery occur beyond the pancreas at the base of the transverse mesocolon (Fullen zone 2, between the pancreaticoduodenal and middle colic branches of the artery), also. 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.69,97,98 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.99 Profound vasoconstriction of the visceral vessels, however, may compromise the viability of distal segments of the small bowel and the right colon. This is the most important reason for these patients to be returned to the operating room in 24–48 hours for a “second look laparotomy.” The value of this approach was confirmed in Asensio et al98 in a multi-institutional study of 250 injuries to the superior mesenteric artery. 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 control100 (Fig. 34-3). 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). 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 considered for repair, since ligation in this area is distal to the connection to collateral vessels from the foregut and the hindgut.101 As this may require microsurgical techniques, however, it is never performed and ligation may mandate extensive resection of the ileum and right colon.102
Argyle shunt in proximal superior mesenteric artery of patient with gunshot wound to upper abdomen.
Same patient as in Fig. 34-3. Shunt has been removed, proximal superior mesenteric artery has been ligated, and view is of aorto-superior mesenteric artery (posterior aspect) bypass graft with autogenous saphenous vein.
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 34-3).69,90,97,103,104,105 Four more recent reviews, including a large multi-institutional study,98 had a mean survival of 58.7%.8,9,93,98 In one of the older series, survival decreased to 22% when any form of repair more complex than lateral arteriorrhaphy was performed.69 Independent risk factors for mortality in the multi-institutional study by Asensio et al 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.98
TABLE 34-3Survival With Injuries to the Superior Mesenteric Artery ||Download (.pdf) TABLE 34-3 Survival With Injuries to the Superior Mesenteric Artery
|Reference ||Year ||No. of patients ||No. of survivors ||Survival (%) |
|6 series69,90,97,103,104,105 ||1972–1986 ||116 ||67 ||57.7 |
|Asensio et al8 (Los Angeles County) ||2000 ||27 (isolated injury) ||11 ||40.7 |
| || ||7 (with other artery) ||2 ||28.6 |
|Asensio et al98 (multi-institutional) ||2001 ||223 ||143 ||61 |
|Davis et al9 ||2001 || 15 ||8 ||53.3 |
|Tyburski et al93 ||2001 || 41 ||20 ||48.8 |
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. Vascular control may be achieved with Henly clamps. Options for repair of either the proximal or distal renal arteries are described later in this chapter (section “Management of Injuries in Zone 2”).
One other major abdominal vessel, the proximal superior mesenteric vein, lying to the right of the superior mesenteric artery, may be injured at the base of the mesocolon. Injury to the most proximal aspect of this vessel near its junction with the splenic vein is difficult to manage. The overlying pancreas, proximity of the uncinate process, and close association with the superior mesenteric artery often preclude easy access to proximal and distal control of the vein. Therefore, as with injuries to the proximal superior mesenteric artery, the neck of the pancreas may have to be transected between noncrushing vascular or intestinal clamps or GIA and/or TA staplers to gain access to the injury. More commonly, the surgeon will find an injury to this vessel inferior to the lower border of the pancreas. Vascular control may be achieved with a small Cooley partial occlusion clamp. Often, the vein can be compressed manually or squeezed between the surgeon’s fingers as an assistant places a continuous row of 5-0 polypropylene sutures into the edges of the perforation. If a posterior perforation is present, multiple collaterals entering the vein at this point will have to be ligated to roll the perforation into view. Occasionally, the vein will be nearly transected and both ends will have to be controlled with vascular clamps. With an assistant pushing the small bowel and its mesentery back toward the pancreas, the surgeon can reapproximate the ends of the vein without tension.
When multiple vascular and visceral injuries are present in the upper abdomen and the superior mesenteric vein has been severely injured, ligation can be performed in the young trauma patient. In three older reviews of injuries to the portal venous system, ligation of the superior mesenteric vein was performed in 27 patients, and 22 survived.81,106,107 In one review of injuries to the superior mesenteric vein, survival was 85% among 33 patients treated with ligation versus 64% in 77 patients who underwent repair.108 Stone et al have emphasized the need for vigorous postoperative fluid resuscitation in these patients as splanchnic hypervolemia leads to peripheral hypovolemia for at least 3 days after ligation of the superior mesenteric vein.107 The survival rate of patients with injuries to the superior mesenteric vein in four series published from 1978 to 1983 was 72.1% (Table 34-4).90,105,106,107 Three more recent reviews had a mean survival of 58.3%.8,9,93
TABLE 34-4Survival With Injuries to the Superior Mesenteric Vein ||Download (.pdf) TABLE 34-4 Survival With Injuries to the Superior Mesenteric Vein
|Reference ||Year ||No. of patients ||No. of survivors ||Survival (%) |
|4 series90,103,105,107 ||1978–1983 ||104 ||75 ||72.1 |
|Asensio et al8 ||2000 ||19 (isolated injury) ||9 ||47.4 |
| || ||14 (with other vein) ||5 ||35.7 |
|Davis et al9 ||2001 ||21 ||15 ||71.4 |
|Tyburski et al93 ||2001 ||32 ||18 ||56.3 |
|Asensio et al109, a ||2007 ||51 ||26 ||51 |
Asensio et al109 reported the largest series in the literature consisting of 51 injuries to the superior mesenteric vein. The mean Injury Severity Score was 25 ± 12, the mechanism of injury was penetrating for 38 (76%) and blunt for 13 (24%), and there were 4 patients who required emergency department thoracotomy 4 (8%). Surgical management consisted of ligation in 30 (59%), primary repair in 16 (31%), and 5 (10%) patients exsanguinated before repair. The overall survival rate excluding patients undergoing emergency department thoracotomy was 51%. The survival rate excluding patients who sustained greater than 3–4 associated injured vessels was 65%. The survival rates of patients with combined superior mesenteric vein and artery injuries was 55%, to the superior mesenteric vein and portal vein (PV) was 40%, while the survival rate of patients with isolated injuries to the superior mesenteric vein was 55%. When mortality was stratified to AAST-OIS grade, survival for grade III was 44% and 42% for grade IV. Survival rates stratified to method of management were 60% for primary repair versus 40% for ligation.
The authors performed a very extensive review of the literature consisting of 401 patients including 127 who underwent primary venorrhaphy, 125 with ligation, and 5 who had interposition grafts (PTFE = 3; saphenous vein = 2) also. Although the data are incomplete in most of the series, survival rates ranged from 17% to 100%.