Advertisement

Early Results of Supporting Free Flap Coverage of Mangled Lower Extremities with Long Saphenous Arteriovenous Loop Grafts.

Open AccessPublished:August 11, 2020DOI:https://doi.org/10.1016/j.avsg.2020.07.056

      Background

      The ability to salvage the mangled lower extremity is both technically challenging and time consuming. It requires the collaborative efforts among multiple surgical specialties in addition to comprehensive post-traumatic wound follow-up. Our institution has integrated a dynamic effort among these specialists in the planning and facilitating a successful limb salvage program with creation of a mangled extremity algorithm. An integral part in this process is the vascular inflow to prepare coverage for large tissue defects lacking adequate recipient targets. Utilization of long saphenous arteriovenous (AV) loop has been cited with minimal data available using larger inflow vessels in the acute trauma setting. We performed a retrospective review and describe our early experience using our protocol with AV loop creation with free flap reconstruction to salvage traumatic leg injuries. Using the data, we sought to develop a mangled extremity protocol for trauma centers to guide mangled limb salvage.

      Methods

      Since June 2016, 398 patients were admitted to our level II trauma facility with isolated traumatic wounds to the lower extremities. Thirty-one limbs were deemed mangled in which 21 received primary amputations due to multiple factors. Ten patients admitted from the trauma service with isolated mangled lower extremities injuries were identified for review. All 10 patients sustained severe crush injuries with large soft tissue defects and decreased perfusion for healing but deemed salvageable by multispecialty assessment. Mangled extremity severity scores were tabulated. Patients age ranged from 21–44 years, with 8 men and 2 women. Repeated debridements until successful sterilization of the wounds were accomplished. Ten long saphenous vein AV loops were anastomosed to the at or above knee popliteal vessels for free flap reconstruction. All patients were followed post-AV loop creation for vascular complications and wound assessments.

      Results

      All 10 patients had sterilization of the wounds with repair of the fracture site before vascular reconstruction. Mean debridement to surgical site sterilization was 4.3 washouts (range 2–7). Successful AV loop creation with long saphenous vein was completed in 100% of patients without vascular complications nor steal events. Free flap tissue transfers directly connected to the loop were completed using 6 rectus abdominis, 3 latissimus dorsi, and 1 anterior thigh graft within 10 days of its creation. Patency rates of the AV loop was 100% with 10 successful flap transfers and 90% amputation free survival. One flap did not survive due to recurrent bacterial infection of the hardware. The 9 patients with successful procedures reached preoperative ambulatory status within 3 months after their final surgery. At 24 months follow-up, 90% amputation free survival is still maintained.

      Conclusions

      Although a small patient cohort, utilization of long saphenous vein AV loop is successful as a bridge to free flap transfer for isolated mangled lower extremities. Development and incorporation of our mangled extremity protocol to guide limb salvage has proven successful in our early experience. Long-term data need to be complied to assess patency of the free flap transfer and quality of life outcomes.

      Introduction

      Despite multiple studies on the successfulness of microvascular transfer for soft tissue defects, no definite recommendations have been made for best practice guidelines for traumatic limb salvage. Across the spectrum of soft tissue defects among patients with critical limb ischemia, oncological and radiation deficits, as well as diabetic foot ulcers, several publications have proven successfulness of free tissue transfers to cover bony defects.
      • Meyer A.
      • Goller K.
      • Horch R.E.
      • et al.
      Results of combined vascular reconstruction and free flap transfer for limb salvage in patients with critical limb ischemia.
      ,
      • Meyer A.
      • Goller K.
      • Horch R.E.
      • et al.
      Results of combined vascular reconstruction by means of AV loops and free flap transfer in patient’s with soft tissue defects.
      Mangled extremities from trauma present a different set of comorbidities. The ability to salvage the mangled lower extremity is both technically challenging and time consuming. It requires the collaborative efforts among multiple surgical specialties in addition to comprehensive post-traumatic wound follow-up. A primarily published series of solely trauma patients with free tissue transfer within a dedicated algorithm incorporating all aspects of care including vascular, orthopedic, plastic, wound care, and nutritional data points is difficult to document. Our institution has integrated a dynamic effort among these specialists in the planning and facilitating a successful limb salvage program with creation of a mangled lower extremity algorithm.
      An integral part in this process is the vascular inflow to prepare coverage for large tissue defects without compromising distal blood flow to the zone of injury. In other literature, muscle flap coverage is usually direct from recipient vessel to target vessel in the free tissue defect. These microanatomies carry a high rate of failure due to recipient arterial injury at the site of tissue transfer.
      • Stranix J.T.
      • Lee Z.H.
      • Jacoby A.
      • et al.
      Not all Gustilo type IIIB fractures are created equal: arterial injury impacts limb salvage outcomes.
      Utilization of a long saphenous arteriovenous (AV) loop to bridge this complication may improve successful outcomes. Long saphenous AV loop creation has been cited with minimal data available with using primarily larger inflow vessels in the acute trauma setting.
      • Cavadas P.C.
      Arteriovenous vascular loops in free flap reconstruction of the extremities.
      • Mambally S.R.
      • Santha K.K.
      Utility of arteriovenous loops before free tissue transfer for post-traumatic leg defects.
      • Lin C.H.
      • Mardini S.
      • Lin Y.T.
      • et al.
      Sixty-five clinical cases of free tissue transfer using long arteriovenous fistulas or vein grafts.
      Our retrospective review of our mangled lower extremity protocol with inclusion of this step in micro transfer may not only benefit limb salvage outcomes in the trauma population but also may be applied to other soft tissue defects from other causes.

      Methods

      Since June 2016, we performed a retrospective review of all isolated traumatic lower extremities wounds admitted by the trauma service at our level II institution. Informed consent and institutional review board’s approval was obtained for this retrospective analysis. Ten patients admitted from the trauma service with isolated mangled lower extremity injuries were identified and followed for limb salvage. All 10 patients sustained severe crush injuries with large tissue defects with questionable vascular perfusion for healing the defect yet deemed salvageable by multispecialty assessment. Mangled extremity severity scores (MESS) were tabulated at the onset of presentation. Patients ages ranged from 21–44 years of age with 8 men and 2 women. After multidisciplinary evaluation by trauma, vascular, orthopedic, and plastic surgery, if the threatened limb was deemed salvageable, interventions were performed. Those patients with multisystem injuries in which the threatened limb was a minor scale injury were excluded from the protocol. The procedural algorithm is displayed in Figure 1.
      Figure thumbnail gr1
      Fig. 1Mangled lower extremity algorithm. CDT, catheter-directed thrombolysis; DVT, deep vein thrombosis.

      Vascular Flow Assessment

      Diagnostic AV studies were performed to assess conduit options for reconstruction. Arteriogram of the affected limb was performed to assess distal runoff. If distal runoff was not intact, endovascular and/or open reconstruction was performed to reinline flow to the extremity. After completion of arterial reconstruction, reassessment of limb salvage was performed by all surgical disciplines to determine limb viability. Venous duplex ultrasound was used pre- and peri-operatively to assess the presence of deep venous thrombosis as well as size and patency of the long and short saphenous vein for AV loop conduit. If a deep venous thrombosis was diagnosed, catheter-directed thrombolysis was considered to reopen venous outflow targets. If AV inflow and outflow options were viable, limb salvage surgical reconstruction was planned.
      • Janhofer D.E.
      • Lakhiani C.
      • Kim P.J.
      • et al.
      The utility of preoperative arteriography for free flap planning in patients with chronic lower extremity wounds.
      • Janhofer D.E.
      • Lakhiani C.
      • Kim P.J.
      • et al.
      The utility of preoperative venous testing for lower extremity flap planning in patients with lower extremity wounds.
      • Wettstein R.
      • Schurch R.
      • Banic A.
      • et al.
      Review of 197 consecutive free flap reconstructions in the lower extremity.

      Surgical Protocol

      Multiple surgical debridements of the wound were performed by the orthopedic trauma service until successful sterilization was accomplished. Intraoperative cultures were performed at the completion of each debridement until a negative result was obtained. Patients were started on broad spectrum antibiotics at onset of presentation and were tailored until sterilization of injury as per microbiology. Once the wound was sterilized, patients underwent a 3-tiered procedural event. First, definitive repair of the fracture was completed by orthopedics. Three days after definitive orthopedic repair of the fracture site with a negative culture result, arteriovenous loop was performed. This was accomplished by construction to larger inflow vessels based on arteriogram, using when appropriate, ipsilateral long saphenous vein (IGSV). This conduit was chosen in contrary to contralateral saphenous vein due to the high risk of ipsilateral limb loss and multisurgeon agreement not to compromise the contralateral limb in the face of potential injured lower extremity amputation.
      • Reddy N.P.
      • Rowe V.L.
      Is it really mandatory to harvest the contralateral saphenous vein for use in repair of traumatic injuries.
      • Woodard E.B.
      • Clouse W.D.
      • Eliason J.L.
      • et al.
      Penetrating femoropopliteal injury during modern warfare: experience of the Balad vascular Registry.

      Peck MA, Clouse WD, Cox MW, et al. The complete management of extremity vascular injury in a local population: A wartime report from the 332 Expeditionary Medical Group/Air Force Theater Hospital, Balad Air Base, Iraq.

      Standard dissection of the ipsilateral popliteal or superficial femoral artery and vein was performed in the injured limb with standard harvest of the IGSV. Prior to clamping, intravenous heparin was administered to achieve an activated clotting time (ACT) > 250 seconds. ACT levels were checked at 30-minute intervals and subsequent doses of heparin were given as needed to maintain the ACT level. The IGSV was placed in the reversed direction and anastomosed to the AV target vessels in a semicircular loop with 5–0 prolene. AV loops once created were placed directly over the fracture site and protected with white foam over the loop and wound vac placed at 50mmhg until free flap transfer (Fig. 2). Once AV loop was constructed, a minimum of 24 hours of maturation lapsed to allow for arterialization and distention of the venous conduit. Depending upon the patient, co-morbidities and surgeon availability, mean time from vascular loop placement to free flap transfer varied, but was no more than 10 days. Ten long saphenous vein AV loops were anastomosed 9 times to the popliteal vessels and once to the superficial femoral vessels. All patients were followed post AV loop creation for vascular complications and wound assessments. After loop construction, the patient was heparinized to a PTT of 75% of therapeutic, started on aspirin 81 mg daily and continued until the free flap transfer was accomplished.
      • Badash I.
      • Burtt K.
      • Leland H.
      • et al.
      Effects of perioperative venous thromboembolism on outcomes in soft tissue reconstruction of traumatic lower extremity injuries.
      ,
      • Valerio I.
      • Sabino J.
      • Heckert R.
      • et al.
      Known preoperative deep venous thrombosis and/or pulmonary embolus: to flap or not to flap the severely injured extremity.
      Decision of free flap tissue transfer (FFT) was performed at the discretion of the plastic surgeon. Mobilization of the rectus abdominis, latissimus dorsi and anterior lateral thigh graft with transfer are described elsewhere.
      • Chung K.C.
      • Disa J.J.
      • Gosain A.
      • et al.
      In summary, at the time of FFT, the AV loop was transected in its mid-segment with the AV sides of the loop anastomosed to the reciprocal donor's muscle flap arterial inflow and venous outflow vessels with 7–0 prolene. Upon immediate completion of the FFT, split thickness skin grafts were taken from the ipsilateral thigh and placed over the muscle flap and wound vac device was secured (Fig. 3). Therapeutic heparin infusion was discontinued 24 hours post-operatively of free flap transfer. A daily 81 mg aspirin regimen was continued indefinitely.
      Figure thumbnail gr2
      Fig. 2Intraoperative completion of popliteal artery to popliteal vein long saphenous loop creation before wound vacuum placement.
      Figure thumbnail gr3
      Fig. 3Postoperative rectus abdominus free flap tissue transfer with split thickness skin grafting.

      Post Hospitalization Treatment

      Once the patient has completed all surgical procedures, follow-up was tiered to orthopedic, vascular and plastic surgical clinics. Post-operative radiography of the fracture site and physical therapy was initiated for each patient. Vascular clinic follow-up included baseline ankle-brachial index, bedside doppler of the flap with AV duplex ultrasound of the flap performed at 1 month, 6 months and yearly to ensure no hemodynamic vascular compromise to the flap (Fig. 4, Fig. 5). If non-invasive doppler shows greater than 300 cm/sec on the arterial side of the loop, arteriogram was considered. Plastic surgery clinic directed wound care assessments and surgical debridement as necessary over the operative site.
      Figure thumbnail gr4
      Fig. 4A 28-year-old male with midshaft tibial fracture from MVC. (A) Intraoperative arteriovenous loop creation after definitive bone cement and ORIF. (B) Six-month postoperative follow-up visit with healed rectus abdominus free flap transfer. MVC, motor vehicle collision; ORIF, open reduction internal fixation.
      Figure thumbnail gr5
      Fig. 5A 44-year-old male 6-month postoperative follow-up visit with open patella fracture from MVC. Successful healed result with anterior lateral thigh graft perfused from distal SFA–SFV arteriovenous loop. MVC, motor vehicle collision; SFA, superficial femoral artery; SFV, superficial femoral vein.

      Results

      During the time frame of this retrospective review, there were 398 isolated lower extremity injuries from trauma ranging from minor incidents to massive hemorrhage from foreign bodies and open fractures. Patients with multiorgan system injury with associated lower extremity severe soft tissue injury requiring distal revascularization were excluded due to the high risk of amputation and death from associated traumatic injuries. Of those, 31 were considered “mangled” but intact at time of presentation. 21 limbs were considered unsalvageable and went on to direct amputation. 15 limbs were removed at the time of surgical exploration due to hemodynamic instability of the patient at time of surgery. Six patients, who at initial operation had too much necrotic tissue for coverage, elected for primary amputation. The 2 remaining patients did not want to undergo multiple surgeries for limb salvage. The remaining 10 patients was our current cohort available for retrospective analysis.
      After trauma bay resuscitation and assessment by the multiple disciplinary team of trauma, orthopedic, vascular and plastic surgery, 8 males and 2 females were deemed salvageable via AV loop and free flap transfer. Mechanisms of trauma included motor vehicle accident in 5, all-terrain vehicle in 3 with one motorcycle and fall injury respectively. MESS scored ranged from 2 to 7 with mean of 5.1. Mid-tibial shaft fractures (Gustillo Grade 3B) were found in 7 patients with 2 pilon and 1 patella injury (Table I). Once hemodynamically stable, all patients followed our proposed algorithm. Successful arteriogram and venous duplex were performed without complications. No arterial injury was identified that required primary reconstruction. No deep venous thrombosis was identified in all 10 patients. Distal runoff included 3 vessels in 4 patients, 2 vessels in 5 patients and one patient with single runoff. All patients had sterilization of the wounds with orthopedic repair of the fracture site prior to vascular reconstruction. Mean debridement to achieve surgical site sterilization was 4.3 washouts (Range 2–7 washouts) followed by open reduction internal fixation of the fracture site. Identified bacteria included Pseudomonas in 4 patients, Enterobacter in 2 patients, and Klebisella and MRSA in one patient apiece. Five patients had no bacteria cultured at the time of initial washout and failed to grow any bacterial counts on subsequent surgeries.
      Table ISummary of mangled lower extremity AV loop—free flap transfer patients
      PatientAge (years)GenderMechanism of traumaInjuryMESS scoreIsolated bacteria# Washouts to sterile wound# Of runoff vesselsVein loop creation# Days to FFTMuscle for FFTPatency time (months)Complication
      123FMVCPilon & Talar3None33Pop A–Pop V6LD33
      233MATVTibial shaft7Pseudomonas52Pop A–Pop V4RA36
      331MMVCTibial shaft5None33Pop A–Pop V3RA30
      421MMVCTibial shaft5MRSA; Enterobacter42Pop A–Pop V2RA40
      528MMCYTibial shaft5Pseudomonas; Enterobacter71Pop A–Pop V5RA38
      624MMVCTibial shaft5Pseudomonas22Pop A–Pop V5LD1BKA
      744MMVCPatella6Klebsiella; Pseudomonas53Distal SFA–Distal SFV10ALTG33
      847MFallPilon & Talar5None42Pop A–Pop V1RA29
      919FATVTibial shaft5None23Pop A–Pop V2LD26
      1048MMVCTibial shaft5None32Pop A–Pop V6RA26Intraoperative aborted LD
      ALTG, anterior lateral thigh graft; ATV, all-terrain vehicle; BKA, below knee amputation; LD, Latissimus dorsi; MCY, motorcycle; MRSA, methicillin-resistant Staphylococcus aureus; MVC, motor vehicle collision; Pop A, popliteal artery; Pop V, popliteal vein; RA, rectus abdominus; SFA, superficial femoral artery; SFV, superficial femoral vein.
      Nine successful popliteal and one superficial femoral AV loop creation with long saphenous vein was completed in 100% of patients without vascular complications nor steal events with all patients having suitable IGSV. No contralateral venous conduit nor cryopreserved vessel was used. All patients were heparinized to PTT of 75% of therapeutic and given 81 mg aspirin by mouth daily without thrombosis of any loop before free flap transfer. Free flap tissue transfers were completed using 6 rectus abdominis, 3 latissimus dorsi, and 1 anterior lateral flap within 10 days of the loop creation with a mean 4.5 days post-AV loop creation. One patient had an aborted latissimus dorsi intraoperative due to small target vessel but reflapped to a successful rectus abdominis 3 days later. Patency rates of the AV loop was 100% with 10 successful flap transfers. One flap did not survive resulting in a below knee amputation due to recurrent bacterial infection of the hardware from pseudomonas despite achieving surgical site sterilization. Distal runoff had no influence on flap failure in this series. The 9 patients with successful procedures reached preoperative ambulatory status within 3 months after their final surgery. Thus far, follow-up duplex ultrasound at 1, 6, 12, 18, and 24 months showed no hemodynamic stenosis of the arterial side of the flap requiring interventions. Twenty-four month amputation free survival is 90%.

      Discussion

      A dedicated algorithm for successful management of the mangled lower extremity has not been clearly established. Multiple papers on soft tissue defects in patients with chronic limb ischemia, oncological and radiation disease, as well as diabetic foot ulcers make it difficult to compose a consensus statement concerning the successfulness of FFT.
      • Quniones-Baldrich W.J.
      • Kashyap V.S.
      • Taw M.B.
      • et al.
      Combined revascularization and microvascular free tissue transfer for limb salvage: a six-year experience.
      ,
      • Sunar H.
      • Aygit C.A.
      • Afsar Y.
      • et al.
      Arterial and venous reconstruction for free tissue transfer in diabetic ischemic foot ulcers.
      The creation of vascular reconstruction for free flap tissue transfer is an established therapy for these former groups. In most cases, AV loops are used as a “last resort” connection as most patients in this category have calcified vessels with infrainguinal occlusive disease requiring bypass surgery for inflow to accept an FFT.
      • Vermassen F.E.
      • van Landuyt K.
      Combined vascular reconstruction and free flap transfer in diabetic arterial disease.
      Extensive tibial occlusive disease makes FFT very challenging to sew the flap to these diseased vessels even after bypass.
      • Hughes K.
      • Domenig C.M.
      • Hamdan A.D.
      • et al.
      Bypass to plantar and tarsal arteries: an acceptable approach to limb salvage.
      In the cases of trauma, most patients tend to be younger with decreased risk factors for atherosclerotic disease. An AV loop is tolerated much better because of the lack of disease making the risk of lower extremity steal minimal and thus decreased risk for limb ischemia.
      We calculated the MESS for each of our patients at the initial presentation of trauma. It has been suggested by past literature that MESS and other scoring systems may assist in the decision-making process for limb salvage.
      • Shanmuganathan R.
      The utility of scores in the decision to salvage or amputation in severely injured limbs.
      However, most scoring systems are only as good as the center and team of physicians in the facility that may use them. Certain limbs may be salvageable regardless of scoring system in an advanced tertiary system, such as ours, versus a lesser equipped smaller institution.
      • Ball C.G.
      • Sutherland F.R.
      • Dixon E.
      • et al.
      Surgical trauma referrals from rural level III hospitals: Should our community colleagues be doing more or less?.
      • Clemmer T.P.
      • Orme J.F.
      • Thomas F.O.
      • et al.
      Outcome of critically injured patients treated at Level I trauma centers versus full-service community hospitals.
      • Harrington D.T.
      • Connolly M.
      • Biffl W.L.
      • et al.
      Transfer times to definite care facilities are too long: a consequence of an immature trauma system.
      In a more doubtful patient presentation, a scoring system can provide a threshold guideline for decision making. Sheean et al. has shown that there has been no difference between MESS values of those patients treated with limb salvage versus amputations in the combat setting.
      • Sheenan A.J.
      • Krueger C.A.
      • Napoierala M.A.
      • et al.
      Evaluation of the mangled extremity severity score in combat related type III open tibia fracture.
      This conclusion has also been supported by multiple authors in the trauma and orthopedic literature.
      • EgeT Unlu A.
      • Tas H.
      • Bek D.
      • et al.
      Reliability of the mangled extremity severity score in combat-related upper and lower extremity injuries.
      ,
      • Kumar R.S.
      • Singhi P.K.
      • Chidambaram M.
      Are we justified doing salvage or amputation procedure based upon mangled extremity severity score in mangled upper extremity injury?.
      Combat injuries and traumatic wounds all tend to involve the same set of decision-making parameters. As in those studies and in our small cohort, MESS score nor other similar scoring systems are neither sensitive nor accurate in predicting amputations.
      • Hohenberger G.M.
      • Konstantiniuk P.
      • Cambiaso-Daniel J.
      • et al.
      The mangled extremity severity score fails to be a good predictor for secondary limb amputation after trauma with vascular injury in central Europe.
      ,
      • Dua A.
      • Desai S.S.
      • Shah J.O.
      • et al.
      Outcomes predictors of limb salvage in popliteal artery injury.
      Overall, several authors have concluded that the scoring system needs to be revisited and revised to understand its utility and relevance in the current trauma paradigm.
      • Loja M.N.
      • Sammann A.
      • Dubose J.
      • et al.
      The mangled extremity score and amputation: time for a revision.
      • Schiro G.R.
      • Sessa S.
      • Piccioli A.
      • et al.
      Primary amputation vs limb salvage in mangled extremity: a systematic review of the current scoring system.
      • Yet B.
      • Perkins Z.B.
      • Rasmussen T.E.
      • et al.
      Combing data and meta-analysis to build Bayesian networks for clinical decision support.
      • Fodor L.
      • Sobec R.
      • Sita-Alb L.
      • et al.
      Mangled lower extremity: can we trust the amputation scores?.
      Our one below knee amputation presented with a favorable MESS value despite recurrent bacterial infection leading to limb loss. We used MESS purely as a documented statistic rather than a parameter for decision making. Perhaps a larger patient cohort will be able to better assist us in evaluating the true utility of this variable.
      In the creation of our treatment algorithm, associated use of AV loops in similar patient groups were researched to evaluate its effectiveness and its staging process. Multiple papers have shown that connections to larger inflow vessels, popliteal and proximal, in the affected lower extremity with a 2-stage approach will have less thrombotic complications.
      • Vogt P.M.
      • Steinau H.U.
      • Spies M.
      • et al.
      Outcome of simultaneous and staged microvascular free tissue transfer connected to arteriovenous loops in areas lacking recipient vessels.
      Bleeding and thrombosis leads to a high rate of transfer failure among all patient groups including trauma, radiation, oncological, and atherosclerotic groups.
      • Demiri E.C.
      • Hatzokos H.
      • Dionyssiou D.
      • et al.
      Single stage arteriovenous short saphenous loops in microsurgical reconstruction of the lower extremity.
      A staged procedure also allows for a more reliable loop by allowing for distention of the loop at physiologic pressures to sustain receiving the free flap. Therefore, we choose a 2-stage approach with connections to larger inflow vessels in the hopes of avoiding these high-risk complications. Benefits of a 2-staged approach allow for AV loop maturation, decreased risk of loop thrombosis, and shorter operative times.
      • Radwan M.S.
      • Barakat A.Z.
      • Jaber M.M.
      • et al.
      Free flap transfer with arteriovenous loop establishment for upper limb salvage in a crush injury.
      ,
      • Rajan S.
      • Mambally T.
      • Santha K.K.
      Utility of arteriovenous loops before free tissue transfer for post-traumatic leg defects.
      As a result of this decision, no vascular complications occurred.
      In review of the current literature on free flap tissue transfer, surgical site sterilization did not seem of prime importance. In the trauma population where most injuries involve a contaminated field of injury, site sterilization seems vital to limb salvage. Stone et al. found surgical site sterilization is fundamental for limb salvage in the treatment of infected vascular bypass grafts.
      • Stone P.A.
      • Mousa A.Y.
      • Hass S.M.
      • et al.
      Antibiotic-loaded polymethylmethacrylate beads for the treatment of extracavitary vascular surgical site infections.
      • Stone P.A.
      • Back M.R.
      • Armstrong P.A.
      • et al.
      Evolving microbiology and treatment of extracavitary prosthetic graft infections.
      • Stone P.A.
      • Armstrong P.A.
      • Bandyk D.F.
      • et al.
      Use of antibiotic-loaded polymethylmethacrylate beads for the treatment of extracavitary prosthetic vascular graft infections.
      Ultimate failure of reconstruction was directly attributed to persistent bacterial counts within the surgical sites. Often sartorius or vastus muscle flaps with antibiotic beads for femoral graft salvage were used to cover the soft tissue defect over exposed bypass grafts. Failure of these muscle flaps were seen in those patients without sterile wounds. This correlation was applied to our series. Antibiotic beads were used until wound cultures proved site sterilization. Once achieved, only then was AV loop and free flap transfer planned. In our series, our one failure came from recurrent pseudomonas infection. Therefore, the importance of serial washouts and surgical site sterilization cannot be overemphasized.
      Diagnostic arteriography was used in each of our patients to predict a potential steal phenomenon and assess distal runoff.
      • Janhofer D.E.
      • Lakhiani C.
      • Kim P.J.
      • et al.
      The utility of preoperative arteriography for free flap planning in patients with chronic lower extremity wounds.
      Each of our traumatic flaps were performed using larger inflow and outflow vessels. The evaluation of a steal phenomenon with AV loop placement and delayed flap transfer was not witnessed even in the 2-staged approach. Microvascular steal has been documented in the literature but is rare.
      • Stranix J.T.
      • Lee Z.H.
      • Jacoby A.
      • et al.
      Not all Gustilo type IIIB fractures are created equal: arterial injury impacts limb salvage outcomes.
      Stranix et al. showed steal is more common in patients with arterial injury at the site of the fracture when compromising arterial outflow. They showed a direct correlation between tibial vessel runoff and vascular complications. Two and single vessel runoff often lead to poor distal perfusion and a potential steal phenomenon when tibial recipient vessels were used for free tissue transfer. The lack of steal in our patient cohort is most likely due to our trauma patients were younger with minimal comorbidities including diabetes, end-stage renal disease, hyperlipidemia, cardiac, and peripheral vascular disease. The trauma populations tend to have minimal atherosclerotic distal vasculature where the tendency of steal will be less due to lack of calcified disease. In addition, we were able to avoid this event by using the popliteal and superficial femoral artery as the inflow vessel where the chance for a steal event is minimized.
      AV loops were used in all our study group secondary to ensuring patent noninjured inline flow was available for the free tissue transfer. No bypasses were needed as no acute occlusions or calcified vessels were encountered. All patients had no risk factors for atherosclerotic plaque. Free flap studies for radiation ulcers and diabetic disease have had calcified vessels with diffuse superficial femoral and tibial disease requiring open surgical bypass to provide a new inflow for free flap transfer.
      • Meyer A.
      • Goller K.
      • Horch R.E.
      • et al.
      Results of combined vascular reconstruction by means of AV loops and free flap transfer in patient’s with soft tissue defects.
      ,
      • Sunar H.
      • Aygit C.A.
      • Afsar Y.
      • et al.
      Arterial and venous reconstruction for free tissue transfer in diabetic ischemic foot ulcers.
      AV loops provide direct high shunt flow for both inflow and outflow with fresh end to end connection to the recipient flap. We found that using tibial vessels for inflow in these large traumatic defects did not provide adequate circulatory flow for flap acceptance. In addition, small tibial vessels also have a high risk of arterial spasm and poor venous outflow for flap failure. Several authors have demonstrated that failure of free flap was associated more with flap transfer to an injured or diseased vessel.
      • Stranix J.T.
      • Lee Z.H.
      • Jacoby A.
      • et al.
      Not all Gustilo type IIIB fractures are created equal: arterial injury impacts limb salvage outcomes.
      ,
      • Lin C.H.
      • Mardini S.
      • Lin Y.T.
      • et al.
      Sixty-five clinical cases of free tissue transfer using long arteriovenous fistulas or vein grafts.
      A strong association was found between the presence of any arterial injury and an increased flap complication rate when the traumatized vessel was used for microvascular connection.
      • Stranix J.T.
      • Lee Z.H.
      • Jacoby A.
      • et al.
      Not all Gustilo type IIIB fractures are created equal: arterial injury impacts limb salvage outcomes.
      In most lower extremity trauma, the tibial vessel mostly injured was the anterior tibial mid-calf and the posterior tibial vessel distally. Therefore, utilization of recipient vessels for AV conduits to larger inflow vessels not only avoids the zone of injury but also confirms the importance of preoperative AV mapping.
      • Janhofer D.E.
      • Lakhiani C.
      • Kim P.J.
      • et al.
      The utility of preoperative arteriography for free flap planning in patients with chronic lower extremity wounds.
      ,
      • Janhofer D.E.
      • Lakhiani C.
      • Kim P.J.
      • et al.
      The utility of preoperative venous testing for lower extremity flap planning in patients with lower extremity wounds.
      The AV loop also admonishes the risk of microvascular flap thrombosis by providing a fresh tissue bridge for the flap connection. Therefore, any attempt at a direct connection at the tibial level carries a high risk for failure and was not incorporated in our protocol.
      The importance of optimization of medical and surgical management cannot be overemphasized in the patient cohort to achieve a healed wound. If surgical site sterilization is not completed and nutritional status is not maximized, surgical reconstruction will be delayed. It is well known that poor nutritional status and sepsis are clear factors to free flap failure.
      • Haughey L.
      • Barbul A.
      Nutrition and lower extremity ulcers: Causality and/or treatment.
      • Patel G.K.
      The role of nutrition in the management of lower extremity wounds.
      • Quain A.M.
      • Khardori N.M.
      Nutrition in wound care management: a comprehensive overview.
      Diets with high-protein and calorically balanced are well known to maximize wound healing from the inside out.
      • Gruen D.
      Wound healing and nutrition: Going beyond dressings with a balanced care plan.
      During our pretreatment of patients and throughout their rehabilitation process, prealbumin levels and nutritional evaluations were routinely conducted throughout the healing process. When necessary, protein and vitamin supplements were given to patients and laboratories redrawn to ensure nutritional support. All patients in our small sample size had normal prealbumin levels and were given vitamin supplementation. We believe that this diligence was vital to successful outcomes.
      We must acknowledge the limitations of this study. This single-center retrospective review has its inherent selection bias, a limited number of subjects and follow-up. Orthopedic repair and debridement, revascularizations, as well as free flap transfers were performed by multiple different surgeons across specialties. It is very difficult to create a prospective randomized trial for this type of study when assessments are swiftly made in the trauma bay. Most decisions tend to be in an emergent fashion where resuscitation and stability of the patient trumps limb salvage. Finally, we have no comparison group to evaluate limb salvage rates across this group. Most often, below knee mangled extremity wounds are often open with a high rate of infection. If the patient is septic from their injury, primary amputation is among the more common intervention, especially in the older population. This investigation had a cohort of patients not older than 50 years. Only long-term data and patient selection at the time of injury, will we be able to possibly extrapolate data and success of this protocol to older populations.

      Conclusion

      Although a small patient cohort, our retrospective review with incorporation and utilization of our mangled extremity protocol to guide traumatic limb salvage has proven successful in our early experience. Utilization of the long saphenous vein for creation of an AV loop graft as a bridge to the free flap transfer in a 2-staged procedure tends to avoid the high-risk thrombotic complications and free flap failure. With the successfulness of this protocol, we hope that this is an early model to build on to maximize acute limb salvage at all trauma centers. Long-term data need to be complied to assess patency of the free flap transfer and quality of life outcomes.

      References

        • Meyer A.
        • Goller K.
        • Horch R.E.
        • et al.
        Results of combined vascular reconstruction and free flap transfer for limb salvage in patients with critical limb ischemia.
        J Vasc Surg. 2015; 61: 1239-1248
        • Meyer A.
        • Goller K.
        • Horch R.E.
        • et al.
        Results of combined vascular reconstruction by means of AV loops and free flap transfer in patient’s with soft tissue defects.
        J Plast Reconstr Aesthet Surg. 2016; 69: 545-553
        • Stranix J.T.
        • Lee Z.H.
        • Jacoby A.
        • et al.
        Not all Gustilo type IIIB fractures are created equal: arterial injury impacts limb salvage outcomes.
        Plast Reconstr Surg. 2017; 140: 1033-1041
        • Cavadas P.C.
        Arteriovenous vascular loops in free flap reconstruction of the extremities.
        Plastics Reconstruction Surg. 2008; 121: 514-520
        • Mambally S.R.
        • Santha K.K.
        Utility of arteriovenous loops before free tissue transfer for post-traumatic leg defects.
        Indian J Plast Surg. 2015; 48: 38-42
        • Lin C.H.
        • Mardini S.
        • Lin Y.T.
        • et al.
        Sixty-five clinical cases of free tissue transfer using long arteriovenous fistulas or vein grafts.
        J Trauma. 2004; 56: 1107-1117
        • Janhofer D.E.
        • Lakhiani C.
        • Kim P.J.
        • et al.
        The utility of preoperative arteriography for free flap planning in patients with chronic lower extremity wounds.
        Plast Reconstr Surg. 2019; 143: 604-613
        • Janhofer D.E.
        • Lakhiani C.
        • Kim P.J.
        • et al.
        The utility of preoperative venous testing for lower extremity flap planning in patients with lower extremity wounds.
        Plast Reconstr Surg. 2020; 145: 164-171
        • Wettstein R.
        • Schurch R.
        • Banic A.
        • et al.
        Review of 197 consecutive free flap reconstructions in the lower extremity.
        J Plast Reconstr Aesthet Surg. 2008; 61: 772-776
        • Reddy N.P.
        • Rowe V.L.
        Is it really mandatory to harvest the contralateral saphenous vein for use in repair of traumatic injuries.
        Vasc Endovascular Surg. 2018; 52: 548-549
        • Woodard E.B.
        • Clouse W.D.
        • Eliason J.L.
        • et al.
        Penetrating femoropopliteal injury during modern warfare: experience of the Balad vascular Registry.
        J Vasc Surg. 2008; 47: 1259-1265
      1. Peck MA, Clouse WD, Cox MW, et al. The complete management of extremity vascular injury in a local population: A wartime report from the 332 Expeditionary Medical Group/Air Force Theater Hospital, Balad Air Base, Iraq.

        • Badash I.
        • Burtt K.
        • Leland H.
        • et al.
        Effects of perioperative venous thromboembolism on outcomes in soft tissue reconstruction of traumatic lower extremity injuries.
        Ann Plast Surg. 2019; 82: 345-349
        • Valerio I.
        • Sabino J.
        • Heckert R.
        • et al.
        Known preoperative deep venous thrombosis and/or pulmonary embolus: to flap or not to flap the severely injured extremity.
        Plast Reconstr Surg. 2013; 132: 213-220
        • Chung K.C.
        • Disa J.J.
        • Gosain A.
        • et al.
        Operative Techniques in Plastic Surgery. Vol III. Lippincott and Associates, New York, NY2018
        • Quniones-Baldrich W.J.
        • Kashyap V.S.
        • Taw M.B.
        • et al.
        Combined revascularization and microvascular free tissue transfer for limb salvage: a six-year experience.
        Ann Vas Surg. 2000; 14: 99-104
        • Sunar H.
        • Aygit C.A.
        • Afsar Y.
        • et al.
        Arterial and venous reconstruction for free tissue transfer in diabetic ischemic foot ulcers.
        Eur J Vasc Endovasc Surg. 2004; 27: 210-215
        • Vermassen F.E.
        • van Landuyt K.
        Combined vascular reconstruction and free flap transfer in diabetic arterial disease.
        Diabetes Metab Res Rev. 2000; 16: S33-S36
        • Hughes K.
        • Domenig C.M.
        • Hamdan A.D.
        • et al.
        Bypass to plantar and tarsal arteries: an acceptable approach to limb salvage.
        J Vasc Surg. 2004; 40: 1149-1157
        • Shanmuganathan R.
        The utility of scores in the decision to salvage or amputation in severely injured limbs.
        Indian J Orthop. 2008; 42: 368-376
        • Ball C.G.
        • Sutherland F.R.
        • Dixon E.
        • et al.
        Surgical trauma referrals from rural level III hospitals: Should our community colleagues be doing more or less?.
        J Trauma. 2009; 67: 180-184
        • Clemmer T.P.
        • Orme J.F.
        • Thomas F.O.
        • et al.
        Outcome of critically injured patients treated at Level I trauma centers versus full-service community hospitals.
        Crit Care Med. 1985; 13: 861-863
        • Harrington D.T.
        • Connolly M.
        • Biffl W.L.
        • et al.
        Transfer times to definite care facilities are too long: a consequence of an immature trauma system.
        Ann Surg. 2005; 241: 961-966
        • Sheenan A.J.
        • Krueger C.A.
        • Napoierala M.A.
        • et al.
        Evaluation of the mangled extremity severity score in combat related type III open tibia fracture.
        J Orthop Trauma. 2014; 28: 523-526
        • EgeT Unlu A.
        • Tas H.
        • Bek D.
        • et al.
        Reliability of the mangled extremity severity score in combat-related upper and lower extremity injuries.
        Indian J Orthop. 2015; 49: 656-660
        • Kumar R.S.
        • Singhi P.K.
        • Chidambaram M.
        Are we justified doing salvage or amputation procedure based upon mangled extremity severity score in mangled upper extremity injury?.
        J Orthop Case Rep. 2017; 1: 3-8
        • Hohenberger G.M.
        • Konstantiniuk P.
        • Cambiaso-Daniel J.
        • et al.
        The mangled extremity severity score fails to be a good predictor for secondary limb amputation after trauma with vascular injury in central Europe.
        World J Surg. 2020; 44: 773-779
        • Dua A.
        • Desai S.S.
        • Shah J.O.
        • et al.
        Outcomes predictors of limb salvage in popliteal artery injury.
        Ann Vas Surg. 2014; 28: 108-114
        • Loja M.N.
        • Sammann A.
        • Dubose J.
        • et al.
        The mangled extremity score and amputation: time for a revision.
        J Trauma Acute Care Surg. 2017; 82: 518-523
        • Schiro G.R.
        • Sessa S.
        • Piccioli A.
        • et al.
        Primary amputation vs limb salvage in mangled extremity: a systematic review of the current scoring system.
        BMC Musculoskelet Disord. 2015; 16: 372-378
        • Yet B.
        • Perkins Z.B.
        • Rasmussen T.E.
        • et al.
        Combing data and meta-analysis to build Bayesian networks for clinical decision support.
        J Biomed Inform. 2014; 52: 373-385
        • Fodor L.
        • Sobec R.
        • Sita-Alb L.
        • et al.
        Mangled lower extremity: can we trust the amputation scores?.
        Int J Burns Trauma. 2012; 2: 51-58
        • Vogt P.M.
        • Steinau H.U.
        • Spies M.
        • et al.
        Outcome of simultaneous and staged microvascular free tissue transfer connected to arteriovenous loops in areas lacking recipient vessels.
        Plast Reconstr Surg. 2007; 120: 1568-1575
        • Demiri E.C.
        • Hatzokos H.
        • Dionyssiou D.
        • et al.
        Single stage arteriovenous short saphenous loops in microsurgical reconstruction of the lower extremity.
        Arch Ortho Trauma Surg. 2009; 129: 521-524
        • Radwan M.S.
        • Barakat A.Z.
        • Jaber M.M.
        • et al.
        Free flap transfer with arteriovenous loop establishment for upper limb salvage in a crush injury.
        Plast Reconstr Surg. 2018; 6: 1-3
        • Rajan S.
        • Mambally T.
        • Santha K.K.
        Utility of arteriovenous loops before free tissue transfer for post-traumatic leg defects.
        Indian J Plast Surg. 2015; 48: 38-42
        • Stone P.A.
        • Mousa A.Y.
        • Hass S.M.
        • et al.
        Antibiotic-loaded polymethylmethacrylate beads for the treatment of extracavitary vascular surgical site infections.
        J Vasc Surg. 2012; 55: 1706-1711
        • Stone P.A.
        • Back M.R.
        • Armstrong P.A.
        • et al.
        Evolving microbiology and treatment of extracavitary prosthetic graft infections.
        J Vasc Endovasc Surg. Dec 2008-Jan 2009; 42: 537-544
        • Stone P.A.
        • Armstrong P.A.
        • Bandyk D.F.
        • et al.
        Use of antibiotic-loaded polymethylmethacrylate beads for the treatment of extracavitary prosthetic vascular graft infections.
        J Vasc Surg. 2006; 44: 757-761
        • Haughey L.
        • Barbul A.
        Nutrition and lower extremity ulcers: Causality and/or treatment.
        Int J Low Extrem Wounds. 2017; 16: 238-243
        • Patel G.K.
        The role of nutrition in the management of lower extremity wounds.
        Int J Low Extrem Wounds. 2005; 4: 12-22
        • Quain A.M.
        • Khardori N.M.
        Nutrition in wound care management: a comprehensive overview.
        Wounds. 2015; 27: 327-335
        • Gruen D.
        Wound healing and nutrition: Going beyond dressings with a balanced care plan.
        J Amer Col Certified Wound Spec. 2010; 2: 46-49