Background: Superior mesenteric artery (SMA) injuries are rare and often lethal injuries incurring very high morbidity and mortality. The purposes of this study are to review a multiinstitutional experience with these injuries; to analyze Fullen's classification based on anatomic zone and ischemia grade for its predictive value; to correlate the American Association for the Surgery of Trauma-Organ Injury Scale (AAST-OIS) for abdominal vascular injury with mortality; and to identify independent risk factors predictive of mortality, describing current trends for the management of this injury in America.
Design: We performed a retrospective multiinstitutional study of patients sustaining SMA injuries involving 34 trauma centers in the US over 10 years. Outcomes variables, both continuous and dichotomous, were analyzed initially with univariate methods. For the subsequent multivariate analysis, stepwise logistic regression was used to identify a set of risk factors significantly associated with mortality.
Results: There were 250 patients enrolled, with a mean Revised Trauma Score (RTS) of 6.44 and a mean Injury Severity Score (ISS) of 25. Surgical management consisted of ligation in 175 of 244 patients (72%), primary [corrected] repair in 53 of 244 patients (22%), autogenous grafts were used in 10 of 244 (4%), and prosthetic grafts of PTFE in 6 of 244 patients (2%). Overall mortality was 97 of 250 patients (39%). Mortality versus Fullen's zones: zone I, 39 of 51 (76.5%); zone II, 15 of 34 (44.1%); zone III, 11 of 40 (27.5%); and zone IV, 25 of 108 (23.1%). Mortality versus Fullen's ischemia grade: grade 1, 22 of 34 (64.7%). Mortality versus AAST-OIS for abdominal vascular injury: grade I, 9 of 55 (16.4%); grade II, 13 of 51 (25.5%); grade III, 8 of 20 (40%); grade IV, 37 of 69 (53.6%); and grade V, 17 of 19 (89.5%). Logistic regression analysis identified as independent risk factors for mortality the following: transfusion of greater than 10 units of packed RBCs, intraoperative acidosis, dysrhythmias, injury to Fullen's zone I or II, and multisystem organ failure.
Conclusion: SMA injuries are highly lethal. Fullen's anatomic zones, ischemia grade, and AAST-OIS abdominal vascular injuries correlate well with mortality. Injuries to Fullen's zones I and II, Fullen's maximal ischemia grade, and AAST-OIS injury grades IV and V, high-intraoperative transfusion requirements, and presence of acidosis and disrhythmias are significant predictors of mortality. All of these predictive factors for mortality must be taken into account in the surgical management of these injuries.