Penetrating Popliteal Vascular Injury: Surgical Management and Early Outcome During Current War in Taiz –Yemen

Background: Popliteal vascular injury remains a challenging entity, and carries the greatest risk of limb loss among lower extremity vascular injuries. We aim to review our experience with complex penetrating popliteal vascular injuries, thereby focusing on therapeutic challenges, and early outcomes. Methods: From September 2015 to December 2019, we managed total of 728 penetrating vascular injuries with 163 popliteal vascular injuries presented to Authority of Althawra hospital in Taiz. Of 125 patients, 103 patients were fullling the inclusion criteria. Variables were retrospectively collected included patient demographics, mechanism and type of injuries, limb ischemia time, type of vascular reconstruction, associated complications, limb salvage, and mortality. Results: 157 vascular reconstructions were performed for 103 patients with penetrating popliteal vascular injuries, the majority 94 (91.3%) were male. Mean age was 27.3 ± 12.3 years. Popliteal vascular injuries were the second most common accounting for 35% of lower extremity vascular injuries and 22.4% of the total vascular injuries. Nearly half 54 (52.4%) of patients sustained complex popliteal vascular injuries (arterial and venous injuries), 31 (30.1%) isolated arterial injuries, and 18 (17.5%) isolated venous injuries. Management of vascular injury was by interposition graft in 68 (66%), end-to-end in 16 (15.5%), and venous patch in 1(1%). Venous injury was repaired in 53 (51.4%) and ligated in 18 (17.5%). Less than 6 hours from injury to completed revascularization was achieved in 58 (56.3%) patients. The overall fasciotomy was 28 (27.2%) which increased length of hospital stays (17 days vs 7 days, P= The overall limb-salvage rate in our study was 94.2%. During the study period, the most common complication was 14 (13.6%) wound infection, 14 (13.6%) graft thrombosis, 6 (5.8%) bleeding, 4 (3.9%) graft infection. Early limb loss occurred in 6 (5.8%) and the mortality rate was (1.9%). Conclusions: Wartime penetrating popliteal vascular injury is a real challenge. However, team approach and promptly vascular repair found to associate with a remarkable limb salvage rate of 94.2%. We advocate repair of arterial injury with vein graft as the treatment of choice whenever possible.


Introduction
The popliteal artery is the second most commonly injured vessel in the lower extremity in which its injury remains a challenging entity and is frequently associated with high levels of morbidity and poor rates of limb salvage compared with other vascular injuries. (1,2) There is a wide variation in the incidence, cause, and mechanism of vascular trauma depending on the local conditions.
In the current warfare conditions, vascular trauma represents 7-10% of total battle injuries. (3)(4)(5) Popliteal artery injuries (PAI) account for about 5-19% of extremity arterial injuries in civilians (6,7) while in the military setting, the reported incidence of vascular injuries has changed signi cantly since World War I (WWI) until now. The rate in WWI was reported to be 0.4-1.3% and in WWII 0.96%. The rate increased slightly during the Vietnam and Korean wars to 2% − 3%. However, the rate increased to 12% during the recent tours in Afghanistan and Iraq. Of these injuries, 66% occurring in the lower extremities of which PAIconstitute 50-60% of all extremity arterial injuries and had an increased rate of secondary amputation, probably as a result of the associated soft-tissue injuries that accompany improvised explosive device (IED) injury patterns. (8)(9)(10)(11)(12) However, PAI has the highest rates of amputations amongst all lower extremity vascular injuries. Despite technical advancements and the lessons learned during the war era (13,14) , (15) the associated amputation rates are high (10-16%) (13,14,(16)(17)(18) although in the military population remain at approximately 30%, whereas range between 14.5-25% in the literature for civilians. (9,19) The practice of early vascular repair over simple ligation has greatly improved limb salvage rates. (19)(20)(21)(22) Since the rst moment of Yemeni revolution in February 2011, an exponential rise in the number of vascular injuries in Taiz city in Yemen, in which Yemen international hospital received 63 cases of vascular injuries with 10 (16%) patients of popliteal vessels injury that present critical challenges in resource-limited settings of developing countries.(3) Ideally, war injuries should be treated by surgeons having military surgery experience. In fact, civilian surgeons may nd themselves trapped in wars practicing military surgery without prior training or experience in this eld. (15) The purpose of this study was to review our recent experience with penetrating popliteal vascular injuries in Taiz -Yemen, thereby focusing on surgical management, and early outcomes and to highlight lessons learned from that period.

Data Collection
From September 2015 to December 2019, we managed total of 728 penetrating vascular injuries with 163 (125 patients) popliteal vascular injuries presented to Authority of Althawra hospital in Taiz-Yemen. Of 125 patients, 103 patients were ful lling the inclusion criteria. Variables were retrospectively collected included patient demographics, mechanism and type of injuries, limb ischemia time, type of vascular reconstruction, associated complications, limb salvage, and mortality.
Any of the following was considered criteria for exclusion: presented with late complications of PAI (pseudoaneurysms and arteriovenous stulas), primary traumatic amputation of lower limb associated with PAI, blunt PAI, iatrogenic PAI, and incomplete or missed le data during the study period.
All patients were resuscitated in emergency room according to Advanced Trauma Life Support protocols in the hospital eld. The diagnosis of popliteal vascular injuries was based on clinical examination and hand-held Doppler. Hard signs ndings of vascular injury like (distal ischemia, pulsatile bleeding, expanding hematoma, palpable thrill, or bruit) were indications for immediate surgical exploration and repair. For soft signs of vascular injury and no immediate threat to life or limb, patients were admitted for close observation and frequent vascular examination, as we were unable to send patients for computed tomography angiography because of limited sources in the city related to war. Routine x rays of the lower extremity were performed on arrival to assess for bony fractures or dislocation. All patients were diagnosed and operated on within 24 hours. Time of limb ischemia was de ned as the time from injury to revascularization. Limb salvage was de ned as the presence of a viable limb at 1 month after injury, regardless of functional outcome.
Our approach was to perform surgical revascularization as soon as the vascular injury was recognized. Operative exploration of injured vessels was performed via standard incisions, distal and proximal control. Flow and back ow were assessed, and we routinely passed an embolectomy catheter to proximal and distal segments to perform thrombectomy followed by the ushing of the distal segment with heparinized saline. This was followed by de nitive repair. Direct end-to-end anastomosis was performed if approximation of debrided arterial ends were free of tension. When this was not possible, IPVG, using autologous reversed long saphenous vein from the contralateral limb, was done. The prosthetic graft was not used in our study.
Deep venous injuries were repaired rather than ligated if patients were hemodynamically stable and when judged necessary. The venous return was restored after arterial repair. Vascular reconstruction was performed before orthopedic stabilization whenever possible. We did not use temporary intravascular shunting (TIVS). We routinely performed calf fasciotomy (4 compartment via 2 incisions), when compartment syndrome was anticipated. Compartment syndrome was based primarily on the clinical nding of tense calf swelling.
Postoperatively, Frequent monitoring and vascular checks (eg, pulse presence, quality, and capillary re ll) continue for the rst 24-48 hours. The injured lower limb was kept elevated and wrapped with a compressed bandage. Early ambulation (within the rst 24-48 hours) was encouraged. All patients received prophylactic antibiotics, which were continued postoperatively for 3-5 days unless prolonged use was dictated by the presence of obvious contamination or infection. Low molecular weight heparin (LMWH) was administered throughout hospital con nement. Patients with arterial injuries received antiplatelet therapy with 100-mg acetylsalicylic acid routine 90 days postoperatively. Complications and outcomes were reviewed through OPD appointment and telephone survey.

Data and statistical analysis
This study is a retrospective review. The major endpoints are overall limb-salvage and mortality rates.
Subgroup analysis was performed for secondary endpoints including fasciotomy and vascular complications. Numerical values were expressed as mean ± standard deviation. Continuous data were compared with unpaired Student's t-tests. All statistical analyzes were performed using SPSS Statistics 24.0. Variables were compared by using analysis of Chi-square analysis or Fisher exact test. P-values ≤ 0.05 were considered statistically signi cant.

Results
From September 2015 to December 2019, we managed a total of 728 vascular injuries presented to our hospital. During that period, 125 patients presented with 163 popliteal vascular injuries.
Twenty-tow patients were excluded from the study, as they were not candidate for the inclusion criteria.
The overall fasciotomy was 28 (27.2%) of which 16 (15.5%) were prophylactically done immediately post vascular reperfusion and 12 (11.7%) were therapeutic done after clinical diagnosis of compartment syndrome. Associated orthopedic injuries in 63 (61.2%) patients; 50 (48.5%) patients required external stabilization, 3 (2.9%) patients were xed with open reduction and internal xation (ORIF), and 10 (9.7%) patients by plaster casts. Adjacent concomitant injuries included nerve injury in 40 (38.8%) patients, signi cant soft tissue loss requiring skin or muscle aps in 27 (26.2%) patients, and associated major body injuries in 15 (14.6%) patients (Table 3).  The overall limb-salvage rate in this study was 94.2%. 30-days complications in the survival group were: 14 (13.6%) wound infection, 14 (13.6%) graft thrombosis, 6 (5.8%) bleeding and\or hematoma collection, 4 (3.9%) graft infection, 6 (5.8%) above-knee amputations, and pulmonary embolism developed in one case (Table 4). Six patients had above-knee amputation after revascularization. Among them, 2 patients were associated with massive soft-tissue injuries and preoperative neurologic impairment in the injured limb. In spite of good vascular repair, patients had a recurrent infection and sensory and motor loss, they later developed wounds infection and did not regain motor or sensory function in the reconstructed limb. Two patients had failed revascularization and the last 2 patients had a severe infection and graft thrombosis.
All vascular repairs were patent upon hospital discharge. Seventy-ve patients (72.8%) required ICU admission, with a mean length of stay of 1.1 ± 1.4 days. The overall mean length of hospitalization was 9.96 ± 9.6days. The hospital stay was signi cantly longer in patients who had fasciotomy and wound infection compared to patients without fasciotomy or infection (7 days vs 17 days, 8 days vs 21 days, P = 0.0003, P = 0.02 respectively).
The overall mortality rate for patients who sustained penetrating popliteal vascular injuries was 1.9 % (two patients). The rst patient had missed PAI and died 7 hours post vascular repair due to hemorrhagic shock, the second patient developed a pulmonary embolism and died 3rd post-operative day.

Discussion
Austere environments, the lack of usual supplies, and exposure to horri c injuries all a rm Debakey's comment that "war is never a cheerful business.(13) Now, as we approach this fth year of the war in Yemen, we continue to evaluate and report the management of wartime popliteal vascular injury in an effort to enhance the care of such injuries for both military and civilian settings. This report comments on type of injury, management, repair technique, and early outcome.
In this study, 103 patients with popliteal vascular injuries were recorded and most of them were active young patients (mean age was 27.3 ± 12.3 years with 89.3% being less than 45 years) thus, optimal management to control bleeding and reestablish circulation is crucial. The management of complex injuries involving vascular and skeletal elements of the lower extremity remains challenging and still incurs a high incidence of limb loss and morbidity. (23)(24)(25)(26)(27) The management of military vascular trauma has changed considerably as a result of the wars of the 20th century and the signi cant contributions of Debakey, Hughes, Rich, and others. (13,14,28) Gunshot and blast injuries caused the penetrating popliteal vascular injuries in our study. In which gunshot wounds from high-velocity weapons accounted for the majority (81.6%) of popliteal vascular injuries, producing deep cavity wounds frequently associated with fracture and neurovascular injury. A major concern is that repair of venous injuries will result in vein thrombosis and subsequent pulmonary emboli, although support for this scenario is somewhat anecdotal. (35) In the largest recent study, they have found this to be the contrary; in fact, the risk of pulmonary emboli is low in venous repair compare to venous ligation or equivalent. (36) In our study result, pulmonary embolism was recorded in one (1%) patient, in which venous injury was repaired by IPVG. Regardless of long-term results, venous patency during the initial 2 weeks after the injury perhaps improves patency rates in a new arterial anastomosis before development of collateral venous canals.(37, 38) Moore et al. (39) advocate that venous patency for 2 weeks after reconstruction virtually assures long-term patency. Finally, Reagan et al. (36) reported their analysis of a review of more than 100 traumatic military venous injuries. They conclude that management of vein repair versus ligation for traumatic venous injury remains a controversy. In an ideal setting, venous injuries should be repaired when possible and tolerated by the patient especially in a watershed area, as in popliteal venous injury. Repair is especially encouraged to ameliorate the high risk of leg phlegmasia or fascial edema. They found also no signi cantly different infection rates for venous injuries patients who were treated by ligation or venous repair. In our study, there were no signi cantly different infection rates for venous injuries patients who were treated by ligation or venous repair (p = 0.24).
It is a controversial issue that which one should be repaired rst for patients that have both popliteal artery and popliteal vein injuries. Some indicated that rst venous and then arterial repair should be done and thus venous circulation should be improved after arterial revascularization.(40) However some authors reported that arterial repair should be done rst in order to reduce the duration of ischemia. (41) For our report, rst arterial repair was done and thus ischemia duration was kept as short as possible. The shunt was not used because we thought venous circulation was provided partly by collaterals until venous repair was done.
Furthermore, our results con rm that a good limb-salvage rate (94.2%) is achieved without the use of TIVS if revascularization is performed as soon as the arterial injury is recognized. The placement of an TIVS would be an additional step with no real bene ts and may potentially cause vessel complications such as dissection or thrombosis. (42) In support of our contention, other large series have found the use of TIVS not helpful. (27,29,43) However, TIVS may be useful as part of a "damage-control" strategy for patients who are too "unstable" to undergo immediate vascular reconstruction because of other lifethreatening injuries. (44) In this setting, limb perfusion can be maintained through the TIVS until the patient's condition ameliorates at which time vascular repair can be performed.
More than half of the vascular injuries (61.2%) were associated with long-bone fractures in our report. The timing of orthopedic xation in concomitant bone injury is a source of debate. Prior skeletal xation is strongly advocated in some series, (45,46) while more recent reports have highlighted the importance of reducing ischemia time by proceeding with vascular reconstruction rst. (27,47) Wolf et al. (48) reduced ischemia time by using TIVS and then performing orthopedic xation before vascular reconstruction. In our practice, we use vascular repairs rstly in all cases followed by orthopedic xations on a stable base. Based on this experience and that of others, we advocate that de nitive arterial reconstruction should precede orthopedic intervention for combined complex lower-extremity injuries. (27,47,49) Of the 103 patients, 28 (27.2%) patients had associated complication in our study. The most common complication was wound infection (13.6%) and graft thrombosis (13.6%), lower than that reported by Fox et al. (50) the overall complication rate among 30 casualties who suffered a major complication or failed attempted limb salvage was 65% included infection (26%), Ratnayake et al. (51) the most common complication was wound infection (33%) and early graft thromboses (24%), and those of past con icts often related to infection and graft occlusion. (5,13,14,50,52,53) Popliteal vascular injuries are associated with higher rates of compartment syndrome. Predominant risk factors included prolonged ischemia (> 6 h), combined vascular and skeletal injuries, or venous ligation. (23) In our experience, 2-incision fasciotomies were usually performed at the initial operation immediately after restoration of blood perfusion. The technique for a single-incision fasciotomy is a well-described alternative for adequate decompression of the lower extremity however, a more involved surgical dissection is required.(54) Also, the decision to perform fasciotomies was clinical one and its liberal use has been recommended by some groups. (19,23,42,55) The overall fasciotomy rate in this study (27.2%) is superior to previously reported series, (27,29,42,56) and NTDB (50%). (19) The liberal use of fasciotomies appears to be associated with lower rates of amputation but the fasciotomy wounds themselves are a source of morbidity. In fact, the length of stay was signi cantly longer in patients who had fasciotomy compared with no fasciotomy (17 versus 7 days, p = 0.0003). We acknowledge in this series, the fasciotomy wounds were associated with increased morbidity and longer length of hospital stay.
In our study, we found low amputation rates of only 5.8%, superior to previous studies (11% for penetrating injuries) and other series ranging as high as 71%. (19,55) Hafez et al. (27) showed amputation rates of 16% in a series of 550 patients with lower extremity arterial injury, of which 31% corresponded to PAI. Nair et al. (25) reported a series of 117 popliteal artery gunshot wounds with 27% and 50% amputation rates for low and high-velocity injuries, respectively.
We found that amputation rate was signi cantly higher in patients who had wound infection and Fasciotomy (P = 0.007, P = 0.025 respectively). In contrast to previous reports, we found no good preoperative predictors for limb loss, including venous ligation, associated facture, ischemic time (mean 5.6 ± 2.6 hours), and compartment syndrome (P = 0.31, P = 0.48, P = 0.38, P = 0.14 respectively). Although it is generally accepted that skeletal muscles can tolerate ischemia up to 6 hours, we found that the ischemic time alone cannot be used to predict limb viability. Prolonged ischemia is a well-recognized predictor of cell death, but the tolerance period varies between persons, depending on the severity of the ischemia and the presence of collateral ow. So, decreasing ischemic time from admission to restoration of perfusion as close to 6 hours as possible may improve outcomes by increased limb salvage and decreased amputation. The mortality in this series was 1.9% which is similar to previous studies ranging from 1 to 9%. (22,27,57) Limitations of the study: First, this study is retrospective and refers to penetrating injury to the most complicated zone of lower limbt. Second, Database system are not matured enough and lots of information regarding ISS, GCS and MESS are missing or not exist. The often multiple admissions and emergent operating mode with and lack of registrars and uniform data collections prevent important details from being promptly recorded.
Finally, there were no extensive diagnostic radiological procedures and wounds were explored in the operating theatre as soon as possible depending mainly on the clinical ndings. Angiography / Endovascular means was not used in our series. Therefore, it is possible that occult vascular injuries have been possibly missed and those usually present later. Despite these limitations, the overall observations herein are signi cant and add knowledge to report in previous wartime experiences, we think that it is very important to share this information with others.

Conclusions
Wartime penetrating popliteal vascular injury is a real challenge. However, team approach and promptly vascular repair found to associate with a remarkable limb salvage rate of 94.2%. This study represents the rst analysis of popliteal vascular injuries during the contemporary war in Taiz city in Yemen. We advocate repair of arterial injury with vein graft as the treatment of choice whenever possible.