Revascularization for acute blunt popliteal artery injury

Abstract

Case

A 45‐year‐old man was brought to our hospital in pre‐shock after falling from a motorcycle. As we diagnosed him with open fracture of the right femur with leg ischemia, we performed revascularization of injured popliteal artery and treated the leg. The pathological findings showed fragmentation and decrease of elastic fibers and fragmentation of collagen fibers, but no inflammatory cells or intimal hyperplasia, and no dissection.

Outcome

Unfortunately, amputation had to be carried out on the 29th postoperative day due to infection and leg dysfunction. The postoperative course was uneventful. The patient could walk with an artificial leg and was discharged approximately 5 months after popliteal artery replacement.

Conclusions

We report a case of revascularization involving a patient with open fracture of the right femur due to acute blunt popliteal artery injury.

Introduction

Injury mechanisms are divided into penetrating and blunt types.1 Popliteal artery (PA) trauma leads to limb loss more often than any other vascular injury of the extremities, and reported amputation rates following blunt PA injury are 29%2 and 17.6%.3 We herein report a case of revascularization involving a patient with open fracture of the right femur due to acute blunt PA injury. Moreover, as reported pathological findings of the injured PA have been quite limited, we also discuss the findings.

Case

A 45‐year‐old man was immediately brought to our hospital in pre‐shock after falling from a motorcycle. The patient's height was 172 cm and body weight was 90 kg, with a body mass index of 30.4. Although he had been diagnosed with hypertension and diabetes mellitus type 2, he was not being treated. Upon arrival, the patient's consciousness was a little drowsy, his blood pressure was 96/66 mmHg and pulse was 111 b.p.m. However, his blood pressure was unstable and rapid infusion was needed. The oxygen saturation (SpO₂) was 100% after providing oxygen. Physical examination showed a deformed open wound of the right posterior thigh without sensory disturbance, right toes with both motor and sensory disturbance, and a pulseless right PA. Moreover, he had painful deformity of the right upper arm as well as tenderness of the right lateral chest and right lower abdomen. Laboratory examination showed the following: AST, 286 IU/L; alanine aminotransferase, 255 IU/L; lactic dehydrogenase, 856 IU/L; creatine phosphokinase, 392 IU/L; white blood cells, 13,500/μL; serum blood sugar, 355 mg/dL; HbA1C, 12.5%. Right humerus, tibia, and femur X‐rays showed fractures, and computed tomography (CT) revealed right multiple rib fractures and slight hemopneumothorax. There was no massive hemorrhage in spite of the pelvic ring fracture. Moreover, 3‐D enhanced CT showed occlusion of the right PA and popliteal vein (Fig. 1). Although the patient was initially in a hemodynamically unstable condition with multiple injuries, his condition became relatively stable. Therefore, we performed an emergency operation, but some doctors don't do the operation and choose an amputation first. Moreover, even though we treat it, the patient's leg dysfunction will not recover. However, the humerus was splinted and the others were observed. First, in a supine position, the right common femoral artery was exposed through the right inguinal incision to control bleeding during the operation. At the same time, we harvested the left large saphenous vein (LSV) of the medial thigh. Second, in a lateral decubitus position, orthopedic surgeons sterilized the open wound and fixed the dislocated femur using an external fixator. Third, as the severe injury of the muscles and soft tissues made it impossible to identify the injured PA, we could find it using intraoperative ultrasound. The PA was stretched, and was consequently slightly hard and thin, whereas the popliteal vein was intact (Fig. 2). As ultrasound showed a thrombus in the PA and we failed to identify the distal PA, we performed thrombectomy using a 4Fr. Fogarty catheter as a palliative treatment. However, the catheter could not be inserted to the distal PA; thus, after we managed to identify the intact PA by ultrasound, PA replacement was carried out with LSV graft approximately 8 h after the injury.

Figure 1.

Three‐dimensional enhanced computed tomography of a 45‐year‐old man with acute blunt popliteal artery injury. The scan shows occlusion of the right popliteal artery (solid arrow) and vein (dotted arrow), which seemed to be stretched by the right broken femur.

Figure 2.

The popliteal artery was stretched, and consequently slightly hard and thin (arrows), whereas the popliteal vein was intact, in a 45‐year‐old man with acute blunt popliteal artery injury. We failed to carry out thrombectomy using a 4Fr. Fogarty catheter.

Hematoxylin–eosin staining showed destruction of the artery and fibrin–blood clot without inflammatory cells and intimal hyperplasia as well as dissection. Elastica van Gieson staining revealed fragmentation and decrease of elastic fibers as well as fragmentation of collagen fibers (Fig. 3).

Figure 3.

Elastica van Gieson staining, carried out after an emergency operation to treat an open fracture of the right femur with leg ischemia, revealed the fragmentation and decrease of elastic fibers as well as fragmentation of collagen fibers.

Postoperative physical examination showed both motor and sensory disturbance of the right leg without leg ischemia. Because the wound became infected with methicillin‐resistant Staphylococcus aureus, linezolid (1,200 mg/day for 14 days) and daptomycin (350 mg/day for 8 days) were given i.v. At the same time, we continued to deterge the infectious leg after debridement twice a day. However, the patient spiked a high fever of approximately 39°C and laboratory examination showed a white blood cell count of 9,480/μL and C‐reactive protein of 21.59 mg/dL. Although the patient's diabetes mellitus was well controlled with miglitol (150 mg/day) and linagliptin (5 mg/day) and laboratory examination showed HgbA1C of 6.6%, due to infection and neurological disability, right above‐knee amputation was carried out on the 29th postoperative day. Osteosynthesis for right humerus fracture was carried out on the 50th postoperative day. The patient's postoperative course was uneventful. He learnt to walk with an artificial leg and was discharged approximately 5 months after PA replacement.

Discussion

Mattox et al. reviewed civilian vascular injuries in the USA involving upper extremities (29.7%), lower extremities (26.7%), abdomen (25.4%), neck (11.0%), and chest (7.2%). The majority of patients were young males, and the causes of most injuries are gunshot wounds (42.4%), stab wounds (33.1%), blunt trauma (14.1%), and shotgun wounds (3.0%).4 The incidence of vascular trauma ranges from 0.2% to 4%.1 In Japan, as there are few gunshot and shotgun wounds, it can be assumed that vascular injuries are rare. In the present case, injured PA replacement was carried out with the contralateral LSV, however, we should have used a temporary shunt5 for immediate restoration of blood flow as well as performed a fasciotomy of the right lower leg.

The mangled extremity severity score (MESS) is a predictor after trauma to determine the need for salvage versus empiric amputation,6 and it may be a more effective predictor of amputation than time from injury to treatment of >6 h.3 Reportedly, 100% of patients with MESS ≥7 required an amputation,6 and 37% of patients with MESS ≥ 7 required it.3 In the present case, the MESS was 6 points, involving: skeletal/soft tissue injury, 2 points; limb ischemia, 2 points; shock, 1 point; and age, 1 point. As MESS does not take into account wound infection or leg dysfunction, our result may conflict with previous reports.

The pathobiology of the injury response after angioplasty has been reported that the angioplasty leads to endothelial cell injury, which leads to luminal thrombosis resulting in occlusion.7 As the acute blunt PA injury occurred very quickly, the mechanism of occlusion on acute injury is different from that on angioplasty. However, the mechanism of occlusion due to acute PA injury still remains unclear, and reported pathological findings have been quite limited. In the present case, hematoxylin–eosin staining showed destruction of the artery, while Elastica van Gieson staining revealed the fragmentation and decrease of elastic fibers as well as fragmentation of collagen fibers. Spasm and/or stretch of the injured artery, which caused luminal stenosis, may be result in occlusion process.8 However, we speculated that whole arterial damage did not activate AKT, which is important for cell survival by preventing apoptosis.9 Thus, apoptosis may occur and lead to thrombosis then occlusion.

Conflict of Interest

None.