Omentopexy for limb salvage in Buerger's disease: indications, technique and results.

S Talwar, SK Choudhary 
 Department of Cardiothoracic and Vascular Surgery, All India Institute of Medical Sciences, New Delhi, India. , India

Correspondence Address:
S Talwar
Department of Cardiothoracic and Vascular Surgery, All India Institute of Medical Sciences, New Delhi, India.
India

Full Text

Buerger’s disease (Thromboangitis Obliterans) is a condition characterised by segmental occlusion of small and medium sized arteries of the lower and sometimes of upper extremities in young male smokers, often associated with migratory thrombophlebitis.[1],[2] Its treatment has remained an enigma and multiple strategies have been employed. Drug therapy is of little benefit.[2],[3],[4] Surgical treatment options have consisted of sympathectomy,[5] direct arterial surgery,[6] adrenalectomy,[7] and amputation as a last resort.[3] With the exception of cessation of smoking, none of these measures is curative and conflicting results have been obtained.[2],[3],[4],[7],[8]

However, in patients with critical limb ischaemia, surgery is required to salvage the limb. Traditionally, patients who have ischaemic signs and symptoms have been offered sympathectomy[5] despite the fact that relapses are frequent due to normalisation of vasomotor tone within two weeks to six months after operation.[7],[9] Results of adrenalectomy also continue to be disappointing.[10]

Arterial reconstruction is usually impossible due to distal nature of the disease and carries a high failure rate.[12] These considerations have always prompted surgeons to look for an alternative solution in the form of omental transfer. In this review, we discuss the historical aspects, technical considerations and results of omental transfer for this limb-threatening condition.

::   Historical aspects

The vascularising properties of omentum have been known since a long time and have included use for absorption of ascites,[12] Myocardial, cerebral and spinal cord revascularisation,[13],[14],[15] and protection of oesophagogastric anastomosis.[16]

Based on these, pedicled omental transfer was first used by Goldsmith and his colleagues for surgical relief of chronic lymphoedema of lower limbs in 1967.[17] Casten and Alday first used this for 24 cases of atherosclerosis[18] and reported excellent clinical results in terms of relief of symptoms and complete healing of ulceration and gangrenous areas of toes and feet.

::   Surgical anatomy

An understanding of the vascular anatomy of the omental vascular arcade [Figure:1] is crucial to the concept of omental lengthening. The right and the left gastroepiploic arteries and their branches along the greater curative of the stomach form the omental vascular arcade. The branches consist of the right and left omental artery the middle omental artery the accessory omental artery and shot omental arteries. The middle omental artery, which is the major branch further, divides into right and left branch which join the right and left omental arteries. The presence of this omental arcade allows the omentum to be lengthened as far as down the ankle by division of the side branches basing the pedicle on the right or the left gastroepiploic artery.

Alday and Goldsmith[19] performed autopsy studies on 136 adult cadavers and described five types of omental vascular arcades depending upon the level of bifurcation or the absence of the middle omental artery [Figure:2]. Type 1 is most common and involves bifurcation of the middle omental artery near the lower end of the omentum. In type 2 the middle omental artery bifurcates midway between the gastroepiploic arcade and the lower end of the omentum. In type 3, it bifurcates 2-3 centimetres from the gastroepiploic arcade. In type 4 the middle omental artery is absent and the right and left omental arteries form the omental vascular arcade. In type 5, the terminal branch of the splenic artery develops into the left omental artery and the right gastroepiploic artery gives rise to the middle omental artery. The knowledge of these types of variations is important as the line of division of the vessels depends on this.

::   Procedure for omental lengthening

This was just described by Goldsmith and de Los Santos[17] for relief of chronic lymphoedema of the extremities in 1967 and later by us and others.[18],[19],[20],[21],[22],[23],[24],[25],[26],[27],[28],[29],[30] Usually a midline incision is used; however in recent times it has been combined with single stage sympathectomy in which case a transverse incision is preferred.[32] The omentum is freed from the transverse colon along the vascular plane and then from the greater curvature of the stomach taking care to preserve the gastroepiploic arcades and the blood vessel between the arcades. In doing so the pedicle is based on either the right or the left gastroepiploic artery based on the dominance.

This pedicled graft is then lengthened depending upon the vascular anatomy and the branches along the greater curvature of the stomach are tied with silk sutures. As shown in [Figure:3], a subfascial tunnel is then prepared on the anteromedial aspect of the thigh and leg up to the ankle of the affected limbs after making multiple skin incision. The lengthened omentum is passed down through this tunnel from the abdomen and pelvis up to the ankle where it is anchored to the underlying muscle using interrupted silk sutures. The average operating time for the procedure is usually 140-180 minutes.

::   Indications

The traditional indications for omentopexy on patients are[20] failure of lumbar sympathectomy to heal the ulceration or poor demarcation despite lumbar sympathectomy, ulceration not responding to conservative treatment and incapacitating rest pain and claudication after lumbar sympathectomy. However, with the realisation of the short-term benefits of lumbar sympathectomy, single stage lumbar sympathectomy and omentopexy has also been proposed to be equally successful with the advantages of a single stage operation and low cost.[31]

::   Mechanism of action

When the procedure was introduced for patients with atherosclerosis, it was thought that omental transposition works by supplying extra blood to the ischaemic limb. However, this is difficult to believe, as the diameter of omental vessels is roughly one-tenth of the popliteal artery.[32] Later studies have demonstrated that the possible mechanism of action of omental transfer is an increase in local collateral circulation rather than any significant increase in blood flow.[20],[23],[25] It has also been demonstrated that the omentum contains a lipid fraction which promotes neovascularisation.[33],[34] Thus a local action on limb musculature with increased local collateral circulation may be a possible mode of action.

::   Results technical success during surgery

[Table:1], [Table:2]



The operation is easy if performed with the complete understanding of the anatomy of the omental vascular arcade. It is usually possible to lengthen the omentum up to the ankle in nearly all patients. In only three out of 62 cases of pedicled omental transfer performed by us[30] this was not possible and we could bring the omentum down only up to the mid-thigh level. Satisfactory results have been obtained even if the omentum has been brought down up to the mid-thigh level.[27],[29] The technical success of the procedure is reflected by the immediate and late post-operative results (detailed below).

::   Clinical improvement during immediate post-operative period

The immediate post-operative results are an indication of the efficacy of omentopexy. These consist of postoperative relief of rest-pain, increase in claudication distance, failure of progression of gangrene and healing of ulcers. Relief of symptoms has been almost immediate in most series.[20],[21],[22],[23],[24],[25],[26],[27],[28],[29],[30] Patients have reported relief of pain in the ischaemic limb even while they had pain at the abdominal incision site.[30] This has been partly explained by psychological factors and cessation of smoking following surgery; however increase in tissue oxygen saturation points to increased blood flow as the possible mechanism of action.[30] Another important feature of clinical improvement in the post-operative period is an increase in the claudication distance, improvement in skin temperature, and improvement in tissue oxygen saturation as measured by pulse oximetry.[27],[28],[30]

::   Long-term follow-up

At a mean follow-up ranging from 1-5 years in most series,[21],[22],[23],[24],[25],[26],[27],[28],[29],[30],[31],[32],[33],[34],[35],[36],[37] the improvement has been sustained with progressive improvement in claudication distance, healing of ulcers and avoidance of major amputations as evident from [Table:1]. Thus, it has been possible to save the limb in many patients who would otherwise have required below knee or even mid-thigh amputation for relief of pain or gangrene.

::   Objective assessment of results of omentopexy

Objective assessment of the results of omentopexy has been carried out using angiography,[23],[25],[28] measurement of tissue oxygen saturation,[27],[28],[30] digital plethysmography and tread- mill exercise testing.[27]

The measurement of tissue oxygen saturation has been particularly useful as this has improved within hours of surgery and has shown sustained improvement on early and late follow-up [Table:2]. Nishimura et al[35] have shown an increase in muscle blood flow during exercise and reactive hyperaemia by using Xenon (X 133) clearance studies.

Agarwal et al[23] performed postoperative angiography in 50 patients who underwent omental grafting and observed increased number of collaterals at graft site with filling of vessels distal to the block in the limbs. In an extension of the same study,[36] 20 dogs underwent allograft omental transfer in hind limbs after ligation of the femoral artery in 10 of these. At the end of three weeks, exploration of the graft site revealed increased number of collaterals at the graft site with filling of vessels distal to the site of the block. The authors concluded that even a blood group and human leukocyte antigen mismatched omental graft is taken up and revascularises the ischaemic limb.

Bhargava et al[27] performed treadmill exercise testing of the patients before and after omentopexy. In the preoperative period, the claudication free period on treadmill was 2-3 minutes, which increased to 6-9 minutes following omentopexy (p<0.05). Also mean tolerated workload increased significantly. Subodh et al[25] performed post-operative Doppler studies and selective coeliac- axis angiography to study the circulation in the omental graft. In 18 of their 20 cases, the arterial pulsations were heard till the knee on Doppler study. In 2 cases in which they were not heard, there was no improvement in symptoms. However on coeliac-axis angiography, the omental vessels were visualised till mid-thigh in only six and up to the knee in only four patients. The authors concluded that omental transposition probably works by promoting local collateralisation. Similar conclusions were drawn in another study comparing free versus pedicled omental grafts.[20] Khazanchi et al[37] have also reported improved vascularity in the limb on serial Doppler studies after omentopexy.

::   Complications and technical failures

In general, the operation is very safe. Even when the omental graft has autolysed, major complications are unusual. The most frequently encountered complications include prolonged ileus and minor wound infection at the incision sites. Incisional hernia has been reported to occur from the abdominal incision site.[26],[27],[30]

Failures have been shown to result in patients in whom the mobilisation of the omentum has been improper.[30] Majority of these occur if the surgeon is unfamiliar with the anatomy of the omental vascular arcade. Handling of the omentum should be gentle to prevent thrombosis of omental vessels and care should be taken to prevent omental torsion while tunnelling.

Presently, there is no experience with omentopexy in patients who have undergone previous abdominal surgery. In these patients the surgery may be nearly impossible due to extensive adhesions between the omentum and gut.

::   Future directions

As described by us recently, single stage lumbar sympathectomy and omentopexy is rapidly emerging as the procedure of choice in these patients with the advantages of a single stage operation and low cost.[31] However, much work needs to be done in this field. The question regarding the mechanism of action of omentum needs to be answered. Long term prospective randomised and controlled clinical trials with longer follow-up are required to establish this procedure as the first line of management of patients with Buerger’s disease. Till then, the quest for an ideal treatment for this grave limb-threatening condition must continue.

References