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12. Adjunctive Techniques: Proximal Anastomosis of an Infrainguinal Bypass
4.
Identifying a soft arterial segment proximal to the occlusive disease to serve as an inflow source
5.
Identifying a soft arterial segment distal to the occlusive disease to serve as a suitable outflow vessel
6.
Connecting these two arterial segments with a conduit, preferably a single segment of autogenous great saphenous vein
The artery to be used as the inflow vessel is usually selected on the basis of the preoperative angiogram. The inflow vessel may be found to be diseased upon its exposure. The pathology that may be encountered includes a heavily calcified plaque or severe thickening of the wall, especially in redo procedures. If dissecting a more proximal segment of the artery is not possible or reveals a similar pathology, constructing an anastomosis to a diseased inflow vessel may become unavoidable. In this situation, the proximal anastomosis could become very challenging. Proximal and distal vascular control can be accomplished by occluding the vessels from within using balloon occluding catheters. Even in the presence of heavy calcifications, a soft area in the artery may still be identified and used as the arteriotomy site. If that is not possible, a localized endarterectomy may become necessary. In that situation, it is important to perform the endarterectomy without creating a distal dissection and disrupting valuable collaterals. In addition, because the atherosclerotic disease usually extends distally for a long segment, ending the endarterectomy often requires transecting the plaque and leaving a shelf. Consequently, tacking of the endarterectomy endpoint is often necessary.
Saphenofemoral Junction with Femoral Vein Cuff
When constructing an anastomosis to an artery with thickened walls, narrowing of the bypass could occur just distal to the heel, especially if the conduit has a small caliber such as with a reversed vein bypass graft. If a prosthetic conduit is to be used, an 8-mm graft can be selected and the hood can be fashioned to accommodate for the thickening in the arterial wall. If the conduit used is the greater saphenous vein, this narrowing must be avoided. One option is to perform an in situ or a nonreversed free vein bypass. The saphenofemoral junction is used as the hood of the bypass (section “Saphenofemoral Junction with Femoral Vein Cuff”). The saphenofemoral junction is dissected freely. A Cooley clamp is applied to the femoral vein in a partially occluding manner. The saphenous vein is transected to include a 1-mm rim of the femoral vein. The venotomy in the femoral vein is then closed with a 5-0 Prolene running suture. The leaflets of the valve at the saphenofemoral junction are excised under direct vision. The hood created will be able to accommodate for the thickening in the arterial wall.
T-Junction
If the saphenofemoral junction is not available, several techniques could be used to assist in performing the proximal anastomosis without creating a narrowing in the bypass. One option involves using the segment of vein with the largest diameter and an associated side branch. The vein is slit along the posterior wall in a fashion to incorporate the side branch [2, 3, 5]. The shape of the segment of the vein that will be used for the anastomosis will appear as a “T”. Consequently, this technique is referred to as the “T-junction technique” (section “T-Junction”). The T-junction technique can help prevent the narrowing that could develop just distal to the heel. In addition, it can also be used in the distal anastomosis to prevent undesirable angulation in the bypass [4]. The length of the T-junction can be modified according to the size of the arteriotomy and the length of the side branch.
Patch Angioplasty of the Inflow Vessel
Another option is to perform a vein patch angioplasty of the arteriotomy. An incision is then performed in the patch and used as the new site for constructing the proximal anastomosis [2]. In this technique, the vein bypass is sutured to the soft and thin wall of the vein patch, which could prevent the proximal anastomotic stenosis (section “Patch Angioplasty of the Inflow Vessel”).
Patch Angioplasty of the Hood of the Bypass
Another option is to carry out the anastomosis in the usual fashion and then perform a vein patch angioplasty if the bypass appears stenotic. The vein patch angioplasty is started in the hood of the graft and may be extended into the bypass as needed (section “Patch Angioplasty of the Hood of the Bypass”).
Incorporation of Profundaplasty
In the presence of occlusive disease at the orifice of the profunda femoris artery, a profundaplasty may be performed in conjunction with the distal bypass. The arteriotomy in the common femoral artery is extended into the profunda femoris artery. Following the endarterectomy, a vein patch closure of the arteriotomy may be performed. The proximal anastomosis can be carried out as described in the section “Patch Angioplasty of the Inflow Vessel.” Alternatively, the arteriotomy used for the endarterectomy is incorporated in the proximal anastomosis, with the hood of the bypass serving as a patch (Section “Incorporation of Profundaplasty”).
Sartorius Muscle Flap
The subcutaneous tissues are the only layers separating a femoral anastomosis from the skin. If a wound problem develops, wound debridement can result in exposing the graft and the anastomotic suture line. In this situation, one treatment option is to perform a muscle flap to cover the graft and the anastomosis with vascularized tissue. This can allow adequate debridement without the risk of exposing the graft. The sartorius muscle is readily accessible for use as a rotational muscle flap (section “Sartorius Muscle Flap”) [1]. It can also be used prophylactically in high-risk wounds.
Gracilis Muscle Flap
The gracilis muscle is the most superficial muscle on the medial side of the thigh and can serve as a reliable muscle flap to cover groin wounds. Unlike the sartorius muscle flap, it will require a separate incision over the medial thigh. A separate incision can also be made at the knee to incise the insertion into the medial condyle. While the leg is in the frog position, a 10–20-cm-long incision is made.
The blood supply to the gracilis muscle is via the medial femoral circumflex, a branch off the profunda artery.
Once mobilized and transected at the knee, it is retroflexed below the fascia into the groin. Few interrupted 2-0 vicryl sutures are placed to tack the muscle to the inguinal ligament and surrounding tissue. The wound can be closed in layers over a drain.
Website with pics (https://www.microsurgeon.org/gracilismuscle)
Youtube: (https://www.youtube.com/watch?v=FngQbkHtrrE)
Saphenofemoral Junction with Femoral Vein Cuff
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