Shaun M. Gifford

Effect of temporary shunting on extremity vascular injury: An outcome analysis from the Global War on Terror vascular injury initiative

OBJECTIVE Extremity vascular injury during the current war has been defined by anecdotal description and case series. These reports focused on estimation of short-term limb viability and technical description of commonly used adjuncts. Temporary vascular shunting (TVS) has been advocated in current care structures, yet mostly due to war environments, broader statistical scrutiny is lacking. This studys purpose is to provide perspective on TVSs impact on limb salvage, and estimate longer-term freedom from amputation. METHODS Data from the Joint Theater Trauma Registry (JTTR), Balad Vascular Registry (BVR), Walter Reed Vascular Registry (WRVR), electronic medical records, and patient interviews were collected on American Troops sustaining extremity vascular injury from June 2003 through December 2007. Those in whom arterial TVS utilization was identified comprise the TVS group. These were compared with controls with similar injury date and anatomic location managed without TVS. Descriptive statistics were employed establishing overall univariate predictors of amputation and comparison between groups. Proportional-hazards modeling, with propensity score adjustment for systemic injury severity and Level 2 care, characterized risk factors of limb loss and effect of TVS. Freedom from amputation was estimated using Kaplan Meier log-rank methods. RESULTS Cases and controls consisted of 64 and 61 extremity arterial injuries, respectively. Mean follow-up was 22 months (range: 1-54 months). The TVS group was more severely injured (mean injury severity score [ISS]: 18 [SD = 10] TVS vs. 15 [SD = 10] control, P = .05) and more likely to receive Level 2 care (TVS: 26%; control: 10%, P = .02). Overall, a total of 26 amputations occurred (21%). Penetrating blasts, compared with gunshot wounds, were associated with amputation (30% vs. 6%, P = .002). After propensity score adjustment, use of TVS suggested a reduced risk of amputation (relative risk [RR] = 0.47; 95% confidence interval [CI] [0.18-1.19]; P = .11). Venous repair was associated with limb salvage (RR = 0.2; 95% CI [0.04-0.99], P = .05). Associated fracture (RR = 5.0; 95% CI [1.45-17.28], P = .01), and elevated mangled extremity severity score (MESS) ([MESS 5-7] RR = 3.5, 95% CI [0.97-12.36], P = .06; [MESS 8-12] RR = 16.4; 95% CI (3.79-70.79), P < .001) predicted amputation. Amputation-free survival was 78% in the TVS group and 77% in the control group at three years (P = .5). CONCLUSION Temporary vascular shunting used as a damage control adjunct in management of wartime extremity vascular injury does not lead to worse outcomes. Benefit from TVS is suggested, but not statistically significant. Injury specific variables of venous ligation, associated fracture, and penetrating blast mechanism are associated with amputation. Amputation-free survival after vascular injury in Operation Iraqi Freedom is 79% at three years. Further studies to statistically define any possible benefits of TVS are needed.

Outcomes of selective tibial artery repair following combat-related extremity injury

OBJECTIVE Selective tibial revascularization refers to the practice of vessel repair vs ligation or observation based on factors observed at the time of injury. Although commonly employed, the effectiveness of this strategy and its impact on sustained limb salvage is unknown. The objective of this study is to define the factors most relevant in selective tibial artery revascularization and to characterize limb salvage following tibial-level vascular injury. METHODS The cohort of active-duty military patients undergoing infrapopliteal artery repair comprises the tibial Bypass group. A similarly injured cohort of patients that did not undergo operative vascular intervention (No Bypass group) was identified. All tibial vessel injuries were documented by angiography. Data were compiled via medical records and patient interview. The primary outcome measure was failure of limb salvage. Multivariate regression was performed to identify factors associated with revascularization and to describe factors associated with amputation. RESULTS Between March 2003 and September 2008, 135 of 1332 patients with battle-related vascular injuries had documented tibial vessel disruption or occlusion. Of these, 104 were included for analysis. Twenty-one underwent autologous vein bypass at the time of injury (Bypass group), and the remaining 83 patients were managed without revascularization (No Bypass group). Mean follow-up (39 vs 41 months; P = .27), age (25 vs 27 years; P = .66), and mechanism of injury (88% vs 92% penetrating blast; P = .56) were similar, but the No Bypass group had higher Injury Severity Scores (ISS; 16.3 vs 11.7; P < .01). Injury characteristics, including Gustilo III classification (49% vs 43%; P = .81) and nerve injury (55% vs 53%; P = 1.0), were similar. Subjects were more likely to receive tibial bypass with an increasing number of tibial vessel occlusions and documented ischemia on initial exam. However, of the 23 in the No Bypass group with initially unobtainable Doppler signals, 17 (74%) regained pedal flow following resuscitation and limb stabilization. Amputation rates were similar (23% vs 19%; P = .79), but the prevalence of chronic limb pain was lower in the Bypass group (10% vs 30%, respectively; P = .08). Cox regression analysis of amputation-free survival demonstrated an association between mangled extremity severity score >5 (hazard ratio [HR], 2.7; P = .01) and amputation. CONCLUSIONS This report provides outcomes data for wartime tibial vascular injury, which supports a selective approach to tibial artery revascularization. Clinical factors such as ISS and degree of ischemia guide which patients are best suited for tibial vascular repair, while injury-specific characteristics are associated with amputation regardless of revascularization status.

A large animal survival model (Sus scrofa) of extremity ischemia/reperfusion and neuromuscular outcomes assessment: a pilot study.

BACKGROUND Extremity ischemia/reperfusion has been studied mostly in small-animal models with limited characterization of neuromuscular or functional outcome. The objective of this experiment was to report a large-animal survival model of extremity ischemia/reperfusion using circulating, electromyographic (EMG), gate, and histologic measures of injury and limb recovery. METHODS Sus scrofa swine (n = 6; mean, 83 kg) were randomized to iliac artery occlusion for 0 (control), 1 (1 HR), 3 (3 HR), or 6 (6 HR) hours. Restoration of flow after a standard large-vessel reconstructive technique (thrombectomy, heparin irrigation, and patch angioplasty) was performed in each of the control, 1HR, 3HR, and 6HR animals, whereas one animal had iliac artery segment excision with no restoration (NR) of axial flow. One animal had operative exposure but no intervention on the iliac artery (sham). Animals were recovered and closely monitored for 2 weeks. Indicators of ischemia/reperfusion and functional recovery, including circulating markers, EMG measures (complex motor action potential), and Tarlov gate scoring (0-4; 0, insensate/paralyzed to 4, normal posture and no gait abnormality) were measured at 24 hours and 72 hours and 7 days and 14 days. Muscle (peroneus) and nerve (peroneal) were collected during necropsy at 14 days to assess gross and histologic changes. Duplex ultrasound was performed serially during the recovery period to confirm patency of vascular reconstruction. RESULTS There were no deaths or failures of vascular reconstruction. Control had a Tarlov score of 4 and normal EMG measures at each point during recovery (same as sham). Tarlov scores at 1, 3, and 14 days recovery in each of the animals were as follows: 1HR: 3, 3, and 4; 3HR: 1, 2, and 4; 6HR: 1, 2, and 3; and NR: 1, 2, and 4. Complex motor action potential as a percentage of baseline at 1, 2, and 14 days recovery was as follows: 1HR: 56%, 55%, and 84%; 3HR: 9%, 8%, and 57%; 6HR: 5%, 5%, and 16%; and NR: 22%, 28%, and 33%. Muscle and nerve histology was the same in sham, control, and 1HR animals. Moderate degeneration and necrosis was observed in peroneus muscle of the 3HR animals. The peroneal nerve in 3HR demonstrated minimal Wallerian degeneration. Severe necrosis was present, as was minimal regeneration, and peroneal nerve demonstrated moderate Wallerian degeneration in 6HR. CONCLUSION This study reports a new large-animal survival model of extremity ischemia/reperfusion using circulating, functional, and histologic markers of neuromuscular recovery. Findings provide insight into an extremity ischemic threshold after which functional neuromuscular recovery is lost. Additional study is necessary to define this threshold and factors that may move it to a more or less favorable position in the setting of extremity injury.

Methylene Blue Enteric Mapping for Intraoperative Localization in Obscure Small Bowel Hemorrhage: Report of a New Technique and Literature Review

BackgroundSmall bowel sources of obscure gastrointestinal bleeding present both a diagnostic and therapeutic challenge. Due to the normal external appearance of the vast majority of small bowel lesions that cause obscure gastrointestinal bleeding, multiple methods of intraoperative localization have been reported. When an arteriographic abnormality is found, the use of vital dye enteric mapping is one of the most effective localization techniques.Case ReportWe present a new technique combining superselective mesenteric angiography with methylene blue enteric mapping and small bowel resection performed during the same operative procedure. This technique was successfully applied in a patient with a jejunal arteriovenous malformation. Included is a review of methods of intraoperative localization with a focus on vital dye staining-guided enterectomy.

A Collaborative Research System for Functional Outcomes Following Wartime Extremity Vascular Injury

Abstract : Vascular injury with hemorrhage and ischemia is a significant cause of battlefield morbidity (i.e., amputation) and mortality. Recent reports have demonstrated the rate of vascular injury in modern combat to be five times that reported in previous wars. As a result of the volume of vascular trauma incurred, management of these injury patterns is of special importance. Indeed, approaches to vascular trauma (extremity and torso) have witnessed significant changes during the course of the current wars of Iraq and Afghanistan. Therefore, an appraisal of long-term functional outcomes is warranted.

Interpreting comparative died of wounds rates as a quality benchmark of combat casualty care.

BACKGROUND The died of wounds (DOW) rate is cited as a measure of combat casualty care effectiveness without the context of injury severity or insight into lethality of the battlefield. The objective of this study was to characterize injury severity and other factors related to variations in the DOW rate. METHODS The highest monthly DOW (HDOW) and lowest monthly DOW (LDOW) rates from 2004 to 2008 were identified from analysis and casualty report databases and used to direct a search of the Joint Theater Trauma Registry. Casualties from the HDOW and LDOW were combined into cohorts, and injury data were analyzed and compared. RESULTS The HDOW rates were 13.4%, 11.6%, and 12.8% (mean, 12.6%), and the LDOW rates were 1.3%, 2.0%, and 2.7% (mean, 2.0%) (p < 0.0001). The HDOW (n = 541) and LDOW (n = 349) groups sustained a total of 1,154 wounds. Injury Severity Score was greater in the HDOW than the LDOW group (mean [SD], 11.1 [0.53] vs. 9.4 [0.58]; p = 0.03) as was the percentage of patients with Injury Severity Score of more than 25 (HDOW, 12% vs. LDOW, 7.7%; p = 0.04). Excluding minor injuries (Abbreviated Injury Scale score of 1), there was a greater percentage of chest injuries in the HDOW compared with the LDOW group (16.5% vs. 11.2%, p = 0.03). Explosive mechanisms were more commonly the cause of injury in the HDOW group (58.7% vs. 49.7%; p = 0.007), which also had a higher percentage of Marine Corps personnel (p = 0.02). CONCLUSION This study provides novel data demonstrating that the died of wounds rate ranges significantly throughout the course of combat. Discernible differences in injury severity, wounding patterns, and even service affiliation exist within this variation. For accuracy, the died of wounds rate should be cited only in the context of associated injury patterns, injury severity, and mechanisms of injury. Without this context, DOW should not be used as a comparative medical metric. LEVEL OF EVIDENCE Prognostic study, level III.

Endovascular Repair of Innominate Artery Injury Secondary to Air Rifle Pellet: A Case Report and Review of the Literature

Objective: Decreased morbidity makes endovascular treatment preferable for certain central aortic and great vessel injuries. We present a case of penetrating innominate injury, describe considerations of a catheter-based approach, and provide follow-up of repair. Methods: A case report and review of the literature. Results: A 16-year-old man presented with an isolated innominate artery injury following an air rifle wound. Standard transfemoral approach was used to gain access the innominate artery. The injury was treated with an 8 × 35 mm, balloon-expandable, covered stent. Completion imaging confirmed a well-positioned stent with exclusion of the injury and normal flow in distal vessels. There were no symptoms of stent migration or stenosis 1 year following the injury. Conclusions: Specific anatomic characteristics including its proximity to the carotid and vertebral arteries make the endovascular approach to the innominate artery unique. This case demonstrates the viability of catheter-based approaches in treating vascular injury.

Biochemical markers of acute limb ischemia, rhabdomyolysis, and impact on limb salvage

Biochemical markers of ischemia reperfusion injury have been of interest to vascular surgeons and researchers for many years. Acute limb ischemia is the quintessential clinical scenario where these markers would seem relevant. The use of biomarkers to preoperatively or perioperatively predict which patients will not tolerate limb-salvage efforts or who will have poor functional outcomes after salvage is of immense interest. Creatinine phosphokinase, myoglobin, lactate, lactate dehydrogenase, potassium, bicarbonate, and neutrophil/leukocyte ratios are a few of the studied biomarkers available. Currently, the most well-studied aspect of ischemia reperfusion injury is rhabdomyolysis leading to acute kidney injury. The last 10 years have seen significant progression and improvement in the treatment of rhabdomyolysis, from minor supportive care to use of continuous renal replacement therapy. Identification of specific biomarkers with predictive outcome characteristics in the setting of ischemia reperfusion injury will help guide therapeutic development and potentially mitigate pathophysiologic changes in acute limb ischemia, including rhabdomyolysis. These may further lead to improvements in short- and long-term surgical outcomes and limb salvage, as well as a better understanding of the timing and selection of intervention.

Inferior mesenteric artery aneurysm in the setting of chronic colonic vascular ectasia

Colonic vascular ectasia is a condition characterized by dilated submucosal veins, venules, or capillaries found commonly in patients with lower gastrointestinal hemorrhage. We present a case of colorectal ectasia associated with ischemia and an inferior mesenteric artery aneurysm. These pathologic findings may be the result of the vascular ectasia and may add to the natural history of this condition.

Damage Control Vascular Surgery in the Austere Environment

Managing vascular trauma in an austere environment with limited resources will challenge even the most seasoned surgeon. Successful management requires immediate hemorrhage control, and then, the surgeon must make critical decisions for limb salvage to be successful. This chapter highlights the principles of vascular management and provides damage control techniques that can be applied in a wide array of trauma settings.