Impact of Staged Vascular Management on Limb Outcomes in Wartime Femoropopliteal Arterial Injury

Vascular Reconstruction and Limb Loss in Military Tibial Artery Injuries

BACKGROUND

Selective operative management of injuries to the tibial arteries is controversial, with the necessity of revascularization in the face of multiple tibial arteries debated. Tibial artery injuries are frequently encountered in military trauma, but revascularization practices and outcomes are poorly defined. We aimed to investigate associations between the number of injured vessels and reconstruction and limb loss rates in military casualties with tibial arterial trauma.

METHODS

A US military database of lower extremity vascular injuries from Iraq and Afghanistan (2004-2012) was queried for limbs sustaining at least 1 tibial artery injury. Injury, intervention characteristics, and limb outcomes were analyzed by the number of tibial arteries injured (1, T1; 2, T2; 3, T3).

RESULTS

Two hundred twenty one limbs were included (194 T1, 22 T2, 5 T3). The proportions with concomitant venous, orthopedic, nerve, or proximal arterial injuries were similar between groups. Arterial reconstruction (versus ligation) was performed in 29% of T1, 63% of T2, and universally in T3 limbs (P < 0.001). Arterial reconstruction was via vein graft (versus localized repair) in 62% of T1, 54% of T2, and 80% of T3 (P = 0.59). T3 received greater blood transfusion volume (P = 0.02), and fasciotomy was used universally (versus 34% T1 and 14% T2, P = 0.05). Amputation rates were 23% for T1, 26% for T2, and 60% for T3 (P = 0.16), and amputation was not significantly predicted by arterial ligation in T1 (P = 0.08) or T2 (P = 0.34) limbs. Limb infection was more common in T3 (80%) than in T1 (25%) or T2 (32%, P = 0.02), but other limb complication rates were similar.

CONCLUSIONS

In this series of military lower extremity injuries, an increasing number of tibial arteries injured was associated with the increasing use of arterial reconstruction. Limbs with all 3 tibial arteries injured had high rates of complex vascular reconstruction and eventual amputation. Limb loss was not predicted by arterial ligation in 1-vessel and 2-vessel injuries, suggesting that selective reconstruction in these cases is advisable.

Mangled extremity: limb salvage for reconstruction versus primary amputation

PURPOSE OF REVIEW

While MESS has historically influenced limb salvage versus amputation decisions, its universal applicability remains uncertain. With trauma systems expanding and advancements in trauma care, the need for a nuanced understanding of limb salvage has become paramount.

RECENT FINDINGS

Recent literature reflects a shift in the management of mangled extremities. Vascular surgery, plastic surgery, and technological advancements have garnered attention. The MESS's efficacy in predicting amputation postvascular reconstruction has been questioned. Machine learning techniques have emerged as a means to predict peritraumatic amputation, incorporating a broader set of variables. Additionally, advancements in socket design, such as automated adjustments and bone-anchored prosthetics, show promise in enhancing prosthetic care. Surgical strategies to mitigate neuropathic pain, including targeted muscle reinnervation (TMR), are evolving and may offer relief for amputees. Predicting the long-term course of osteomyelitis following limb salvage is challenging, but it significantly influences patient quality of life.

SUMMARY

The review underscores the evolving landscape of limb salvage decision-making, emphasizing the need for personalized, patient-centered approaches. The Ganga Hospital Score (GHS) introduces a nuanced approach with a 'grey zone' for patients requiring individualized assessments. Future research may leverage artificial intelligence (AI) and predictive models to enhance decision support. Overall, the care of mangled extremities extends beyond a binary choice of limb salvage or amputation, necessitating a holistic understanding of patients' injury patterns, expectations, and abilities for optimal outcomes.

Association between time to revascularization and limb loss in military femoropopliteal arterial injuries

OBJECTIVE

Expeditious revascularization is key to limb salvage after arterial injuries, but the relationship between time to revascularization and amputation risk is not well-defined. We aimed to explore amputation risk based on time to revascularization in a cohort of military femoropopliteal arterial injuries.

METHODS

A database of vascular injuries from Iraq and Afghanistan casualties (2004-2012) was queried for femoral (common, superficial, or deep) and/or popliteal arterial injuries that underwent revascularization. Time from injury to initial revascularization (via shunt or reconstruction) was divided into groups of <3 hours, 3 to 6 hours, 6 to 9 hours, and >9 hours, and bivariate comparisons were performed.

RESULTS

Revascularization times were available for 120 cases. Injury and treatment characteristics by time group were generally similar between time groups. Shunting and vein injuries were more common in limbs revascularized earlier, whereas blast mechanism and fasciotomy were more common with later revascularization. Ten cases (8%) underwent revascularization in less than 3 hours, 63 (53%) were revascularized in 3 to 6 hours, 33 (28%) in 6 to 9 hours, and 14 (12%) after 9 hours. Amputation rates within the cohorts were 10%, 21%, 24%, and 50%, respectively (P = .085, χ2 of amputation rates across time groups). The mean ± standard deviation revascularization time for amputated limbs was 442 ± 348 minutes vs 347 ± 183 minutes for salvaged limbs (P = .057). Amputation was performed in 19% of limbs revascularized in <6 hours and in 32% revascularized >6 hours from injury (P = .112). The >9-hour group, however, had a 50% amputation rate vs 21% for those with revascularization in <9 hours (P = .016). Fractures were more common in >9-hour limbs than <9-hour limbs (79% vs 44%; P = .016), but other limb injury characteristics were similar, with no difference in limb injury severity scores. Among 91 salvaged limbs, neither vascular nor other complications were predicted by time to revascularization. All seven >9-hour limbs had a limb complication, most commonly infection (71%), and three (42%) required a skin graft to close their fasciotomies.

CONCLUSIONS

Increasing time from injury to initial revascularization was associated with increasing rates of limb loss. Revascularization within 3 hours of injury resulted in a low amputation rate, whereas one-half of limbs treated after 9 hours were amputated. Arterial shunting was associated with earlier revascularization and should be considered a mainstay of combat casualty vascular care. Forward-deployed surgical assets play a pivotal role in providing early revascularization and reducing rates of limb loss in modern combat casualty care.

Systematic review of temporary intravascular shunt use in military and civilian extremity trauma

BACKGROUND

The use of temporary intravascular shunts (TIVS) in the setting of military and civilian trauma has grown in recent years, predominantly because of the mounting evidence of improved limb outcomes. We sought to characterize the use and outcomes of TIVS in trauma through a systematic review of military and civilian literature.

METHODS

The MEDLINE, EBSCO, EMBASE, and Cochrane databases were searched for studies on TIVS use in military and civilian trauma settings published between January 2000 and March 2021. Reports lacking systematic data collection along with those with insufficient TIVS descriptive and outcome data were excluded. Data regarding the characteristics and outcomes of TIVS were assessed and collective syntheses of military and civilian data performed.

RESULTS

Twenty-one reports were included, 14 from civilian trauma centers or databases and 7 from military field data or databases (total of 1,380 shunts in 1,280 patients). Sixteen were retrospective cohort studies, and four were prospective. Five studies had an unshunted comparison group. Shunts were predominantly used in the lower extremity and most commonly for damage control indications. Dwell times were infrequently reported and were not consistently linked to shunt thrombosis or other complications. Anticoagulation during shunting was sparsely reported and inconsistently applied. Shunted limbs had higher injury severity than unshunted limbs but similar salvage rates.

CONCLUSION

Temporary intravascular shunts are effective for expeditious restoration of perfusion in severely injured limbs and likely contribute to limb salvage. There is a paucity of comparative TIVS data in the literature and no consistently applied reporting standards, so controversies regarding TIVS use remain.

LEVEL OF EVIDENCE

Systematic Review, level IV.

Performance of a novel temporary arterial shunt in a military-relevant controlled hemorrhage swine model

BACKGROUND

In military trauma, temporary vascular shunts restore arterial continuity until delayed vascular reconstruction, often for a period of hours. A novel US Air Force-developed trauma-specific vascular injury shunt (TS-VIS) incorporates an accessible side port for intervention or monitoring, which may improve patency under adverse hemodynamic conditions. Our objective was to evaluate TS-VIS patency in the setting of volume-limited resuscitation from hemorrhagic shock.

METHODS

Female swine (70-90 kg) underwent 30% hemorrhage and occlusion of the left external iliac artery for 30 minutes. Animals were allocated to one of three groups (n = 5 per group) by left external iliac artery treatment: Sundt shunt (SUNDT), TS-VIS with arterial pressure monitoring (TS-VIS), or TS-VIS with heparin infusion (10 μ/kg per hour, TS-VISHep). Animals were resuscitated with up to 3 U of whole blood to maintain a mean arterial pressure (MAP) of >60 mm Hg and were monitored for 6 hours. Bilateral femoral arterial flow was continuously monitored with transonic flow probes, and shunt thrombosis was defined as the absence of flow for greater than 5 minutes.

RESULTS

No intergroup differences in MAP or flow were observed at baseline or following hemorrhage. Animals were hypotensive at shunt placement (MAP, 35.5 ± 7.3 mm Hg); resuscitation raised MAP to >60 mm Hg by 26.5 ± 15.5 minutes. Shunt placement required 4.5 ± 1.8 minutes with no difference between groups. Four SUNDT thrombosed (three before 60 minutes). One SUNDT thrombosed at 240 minutes, and two TS-VIS and one TS-VISHep thrombosed between 230 and 282 minutes. Median patency was 21 minutes for SUNDT and 360 minutes for both TS-VIS groups (p = 0.04). While patent, all shunts maintained flow between 60% and 90% of contralateral.

CONCLUSION

The TS-VIS demonstrated sustained patency superior to the Sundt under adverse hemodynamic conditions. No benefit was observed by the addition of localized heparin therapy over arterial pressure monitoring by the TS-VIS side port.

Outcomes of Arterial Grafts for the Reconstruction of Military Lower Extremity Arterial Injuries

INTRODUCTION

Lower extremity (LE) arterial injuries are common in military casualties and limb salvage is a primary goal. Bypass grafts are the most common reconstructions; however, their specific outcomes are largely unreported. We sought to describe the outcomes of LE arterial grafts among combat casualties and their association with limb loss.

METHODS

Retrospective cohort study of 2004-2012 Iraq/Afghanistan casualties with LE arterial injury undergoing bypass graft from a database containing follow-up until amputation, death, or military discharge. Primary outcome was composite graft complications (GC-thrombosis, stenosis, pseudoaneurysm, blowout, and/or arteriovenous fistula).

RESULTS

Two hundred and twenty-two grafts were included (99 femoral, 73 popliteal, 48 tibial). 56 (26%) had at least one GC; thrombosis was most common in femoral, stenosis most common in popliteal and tibial. GC was not associated with graft level but was associated with synthetic conduit (P = 0.01) and trended towards an association with multiple-level arterial injuries (P = 0.07). Four of eight (50%) synthetic grafts had amputations, all within 72h. Two of the eight synthetic grafts thrombosed, and both limbs were amputated. There were 52 total amputations. Amputation was performed in 13 (23%) of limbs with a GC and 24% of those without (P = 0.93) Overall, 24 (11%) of grafts thrombosed, 16 within 48h and 13 (25%) in limbs undergoing amputation (P = 0.001 for association of thrombosis with amputation).

CONCLUSION

GC are common among LE bypass grafts in combat casualties but are not associated with limb loss. Thrombosis is predominantly early and is associated with amputation. Closer attention to ensuring early patency may improve limb salvage.

Utility of the Mangled Extremity Severity Score in Predicting Amputation in Military Lower Extremity Arterial Injury

BACKGROUND

Effective amputation prediction may help inform appropriate early limb salvage efforts in military lower extremity (LE) arterial injury. The Mangled Extremity Severity Score (MESS) is the most commonly applied system for early amputation prediction but its utility in military trauma is unknown.

METHODS

Retrospective cohort study of Iraq and Afghanistan casualties with LE arterial injury who underwent a vascular limb salvage attempt. Retrospectively assessed MESS was statistically explored as an amputation predictor and MESS component surrogates (mechanism, vascular injury characteristics, tourniquet use, and transfusion volume) were used to characterize limb injuries by presenting characteristics and evaluated for amputation prediction.

RESULTS

A total of 439 limbs were included with 99 (23%) amputations, 29 (7%) within 48 hr of injury. Median MESS was 5 (interquartile range 4-6) among salvaged limbs and 7 (5-9) among amputations (P < 0.0001). An MESS cutoff of ≥7 had a better receiver operating characteristic sensitivity/specificity profile (area under the curve 0.696 overall, 0.765 amputation within 48 hr) than MESS ≥8 (0.593, 0.621), but amputation rates were only 43% for MESS ≥7 and 50% for ≥8. MESS ≥7 was significantly associated with age, polytrauma, blast or crush mechanism, fracture, tourniquet use, distal (popliteal/tibial) and multiple arterial injuries, and massive transfusion. Amputation was significantly associated with polytrauma, blast or crush mechanism, fracture, and massive transfusion; however, 83 casualties had all 4 characteristics with an amputation rate of only 46%.

CONCLUSIONS

In combat casualties with arterial injury, LE amputation after attempted vascular limb salvage is inadequately predicted by existing scoring systems or the presenting characteristics available in this registry. Limb loss is predominantly late and likely because of factors not projectable at initial presentation.