Safety and Efficacy of Single Ankle, Single Popliteal or Combined Ankle and Popliteal Block for Diabetic Foot Surgery: A Comparative Study

Diabetic patients suffering diabetic foot disease regularly have sever co-morbidities, they are more liable to hypertension, ischemic heart disease, autonomic neuropathy, infections and gastric reflux all of which contribute to a high risk profile for anesthesia according to American society of anesthesiologists patients classification.

Anesthetic management for diabetic foot disease surgery is a frequent challenge and should be undertaken with a careful consideration of the anesthetic techniques available.

Hazards of general anesthesia is more likely in diabetic patients as they have low reserves to preserve against additional straining factors during general anesthesia consequently, avoiding general anesthesia in this population may be a central concern to ensure optimal peri-operative management following lower limb surgery. Neuraxial anesthesia is complicated by urinary retention, hypotension and postdural puncture headache and backache. In chronic ischemic legs, with multiple and diffuse stenosis in the leg segmental vessels, hypotension can precipitate thrombosis easily. In addition fluid loading and vasopressor administration may not be ideal methods to treat hypotension since end stage renal disease and coronary artery occlusive disease are common in these patients.

Relative to central nerve block, peripheral limb blocks are more discriminatory in their action and consequently result in less interference of bladder function and motor impairments. Also with peripheral nerve block, patients do not require postoperative fasting that help in preserving patient glycemic control. Moreover. Nerve block anesthesia has the advantages of improved postoperative pain control and it is more economical reducing hospital and associated expenses.

Ankle block alone has high failure rate and require more than usual dose to get effective. In popliteal block larger dose is needed than ankle and there is more time delay. The investigators thought to get the advantages of using local than general anesthesia with combined ankle and popliteal blocks to increase potentiation and decrease doses in diabetic foot surgery.