INTRODUCTION
Saphenous vein grafts have been established as the gold standard conduit for lower extremity bypass grafting [1]. Conventionally, the great saphenous vein (GSV) is typically harvested via a long continuous or “skip” incisions that may extend from the groin to the ankle, before its use as an arterial conduit. This approach, however, is associated with significant morbidities, including surgical site infections, ischemic skin flaps, fat necrosis, lymph leaks, increased postoperative pain, and longer hospital length of stay (LOS) for as many as 24% to 43% of patients [2].Endoscopic vein harvest (EVH) has been demonstrated to improve early morbidity when compared with the conventional open harvest technique (OVH) for infrainguinal bypass surgery. The aim of this article is to report a simple but unique technique to tunnel the vein graft without injury in the usage of reverse saphenous vein grafts in infrainguinal bypass surgeries.
CASE REPORT
A 50 year old male labourer by occupation, was admitted with a non-healing ulcer of the anterior aspect of the tibia with rest pain. He was a chronic smoker with a pack year of 32 and a history of intermittent claudication and rest pain. The peripheral pulse was not palpable infrapopliteally on the left leg. The systemic examinations were within normal limits. Clinical evaluation was suggestive of a Rutherford grade 2, category 4. The patient was maintained on medical management with standard regimens, however he was not symptomatically relieved .He had a claudication distance of 100 metres. Two months later, he sustained a left tibial fracture following a fall at his workplace. He underwent an open reduction and internal fixation of the left tibia at an outside hospital and was referred to us with a non-healing wound over the anterior aspect of the left shin. Doppler evaluation revealed a monophasic flow in the infrapopliteal vessels. He was evaluated with a peripheral CT aortogram, which revealed a completely occluded superficial artery with a two vessel run-off infrapopliteally (Figure 1). The lesion was categorised as TASC II TYPE D, and infra popliteal revascularisation was planned after discussion with the patient and family. We performed a femoropopliteal bypass using autologous reverse saphenous vein grafts, which were harvested by the endoscopic venous harvesting technique.
SURGICAL TECHNIQUE
For EVH, the patient was placed in a supine position and a transverse stab incision was made at the medial tibial condyle. Sharp dissection was carried out to identify the GSV, which was then elevated with a vessel loop. Another stab incision was made in the groin to disconnect the saphenous vein from the saphenofemoral junction. The calf portion of the vein was also harvested by redirecting the catheter caudally, and a separate stab incision was made at the medial calf to disconnect and ligate the vein distally. An ankle incision was not used. EVH was performed with the disposable VASOVIEW 7 EVH System (MaquetInc,Wayne, NJ), using a carbon dioxide insufflation technique (flow set at 5, and pressure of 12 mm Hg) in the perivenous tunnel created by the camera dissector. Bipolar electrocautery (set at 25 V) was employed to divide side branches in situ, with silk ties applied prior to grafting. During blunt tip dissection, a regular sequence of short gentle motions is performed, allowing the CO2 to promoted dissection and ensuring that side branches are dissected thoroughly to allow adequate length for branch division. By providing an adequate margin and keeping electrocautery energy settings on the lowest possible settings, the risk of thermal injury is minimized.
Once removed, the great saphenous vein was dilated with plasmalyte. The side branches were ligated and clipped. For tunnelling the saphenous vein through the submuscular plane we improvised a new technique. We introduced an autoclaved 5Fr Fogarty catheter cover for threading across the tunnel (figure 3). A standard atrium tunneler set was used in the sub sartorial muscular plane. The 5Fr Fogarty cover was threaded along the tunneler. An Ethicon Ethisteel™ no 6 – 75 cm (MNW- 9494) straight tip was used to thread along the Fogarty cover. The end was made into a loop .The reversed end of the vein was attached to the loop end of the Ethisteel™, and the vein was threaded along the whole length of the tunneler. Once the vein reached the desired length for the distal anastomosis, the Fogarty cover was removed. Our remaining attention focused on the construction of proximal and distal anastomoses, as in a standard femoropop- liteal bypass.
DISCUSSION
Arterial bypass is a classic, yet very efficient surgical method of treatment for peripheral arterial obstructive disease in critical ischemia patients, with good results for limb salvage and improvement of quality of life .This method of reconstruction has been utilized in preference to prosthetic bypass on the basis that experimental and clinical studies [1-4] have shown a poor long-term patency rate when synthetic material was utilized to bypass the occluded superficial femoral artery. Minimally invasive vein harvesting techniques were initially introduced in 1994 and have been developed to reduce the wound morbidity associated with open vein harvest (OVH) [5]. Since its introduction in the mid-1990s, EVH has undergone many transformations, with both refinements in harvesting technique and vessel handling, in addition to technological advancements towards more practical and protective features. New-generation EVH systems have been developed to minimize endothelial cell damage secondary to “thermal spread.” They use a bipolar radiofrequency energy source designed to keep thermal spread to a minimum (less than 1 mm), potentially minimizing graft injury.
Although studies shows that EVH may be associated with a decreased rate of wound complications, it is also associated with inferior graft patency in patients treated for critical limb ischaemia, with an increased incidence of severe stenosis within the body of the graft requiring reintervention. Limb salvage and secondary patency rates are similar for OVH and EVH.
To date, despite widespread acceptance of the in situ bypass technique, there is not a scintilla of evidence that use of the in situ-bypass is associated with a patency rate superior to that of concurrently performed reversed vein bypass (in situ versus reverse graft). Various explanations have been advanced in an effort to explain the presumed improved results noted with the in situ bypass, including improved endothelial preservation, preservation of intact vasa vasorum, and improved arterial hemodynamics resulting from an improved size match between the anastomosed proximal and distal vessels. Recent objective studies comparing in situ and reversed grafts have failed to confirm these presumed differences when the requisite critical analyses were performed [6-8] In addition, numerous recent reports describing methods of recognizing and treating postoperative arteriovenous fistulas and valve site stenosis attest to a disturbing incidence of second operations required to maintain patency of in situ grafts of saphenous vein. The use of in situ grafts in the anatomical position can lead to kinking and angulation while entering the deeper anastomotic sites as already described in the literature.
CONCLUSION
We at our centre routinely use reverse saphenous vein grafting for femoropopliteal bypass operations. We have quite commonly encountered the technical problems of vein avulsion and internal bleeding while tunnelling the reverse saphenous vein graft through the subsartorial tunnel. Technical complications encountered while tunnelling the saphenous vein have not been well described in the literature Though people have tried a soft mouldable tunneler, use of the Fogarty catheter hard cover has never been reported in the literature. Although the tunnel created by the endoscopic dissector can be used for the purpose of threading the vein, small intimal tears and stretching on the side branches while tunnelling can lead to disastrous consequences, sometimes resulting in sacrificing the only conduit remaining for the patient. The subsartorial tunnel is superior to the tunnel created by the EVH dissector. This necessitates the use of a tunneler. The use of a Fogarty catheter cover as described can reduce the risk of intimal damage during traction while tunnelling, side branch avulsion, and slipping of ligatures which can result in disastrous consequences of internal bleeding, which forces conversion to an open wound exploration, or resorting to the use of prosthetic grafts which have reportedly lower graft primary, primary assisted and secondary patencies.
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