Skew Flap vs Long Posterior Flap for Below Knee Amputation Early and Short- Term Outcomes

Overview

Below knee amputations (BKAs) are frequently performed among vascular patients with end stage chronic limb threatening ischemia and / or complications of diabetes and diabetic foot infections and gangrene, It may also be necessary for patients with aggressive diabetic foot infections or gangrene, or both; for those with extensive venous ulceration; or following major trauma. and in the case of extremity sepsis. There is two main methods for constructing the myocutaneous flaps in below knee amputation; the long posterior flap (LPF) and skew flap (SF).

Anesthesia BKA could be performed under general anesthesia (GA), epidural anesthesia or under spinal anesthesia . Patient position The patient lies in the supine position. Technique The limb is prepared by an application of povidone iodine solution in the ward 2 h before surgery. The foot and any septic lesion is isolated. The whole limb is wrapped in a dry sterile sheet. Penicillin and metronidazole prophylaxis is used routinely. The operation is performed under general anesthesia with a regional anesthetic technique. The skin flaps are marked on the skin before any incision. And the skin flaps are semicircular. based on a line around the limb at right angles to its long axis, drawn at the plane of bone section 10-12cm from the joint line at the tibial plateau. The skin flaps are cut which includes the fat and deep fascia. but these are not stripped from the underlying muscle more than is required to gain access to the anterior tibial compartment. The saphenous veins are ligated. The periosteum over the tibia is incised where it is exposed and elevated with the skin flap to 2 cm above the line of bone section. The anterior tibial nerve and the peroneal nerve are divided and allowed to retract while the vessels are ligated. The fibula is divided 2cm above the line of tibial bone section. The tibia is divided with a GIGLI saw. Traction on the bone hook exposes the tibialis posterior muscle and this is divided at the line of distal bone section which exposes the posterior tibial artery and its venae comitantes. the posterior tibial nerve and the peroneal artery and its venae comitantes. ligatures applied to each of the vascular bundles. The gastrocnemius and soleus muscle mass can then be separated from the tibia and fibula of the specimen while hemostasis is maintained. The muscle mass is cut transversely, thus freeing the specimen; this must allow a length of muscle below the bone end at least equal to the diameter of the leg. The protruding muscle mass is then thinned from the line of bone section to its extremity . Careful homeostasis is essential and the muscle must not be compressed due to too much bulk or tight constricting sutures. A suction tube drain is drawn through the lateral aspect of the stump above the suture line and placed to collect any fluid in the vicinity of the bone ends. The drain can be removed in 48-72 h; the sutures are removed at 15- 21 days. Follow up Patients will be followed up prospectively intraoperative, during postoperative hospital admission and late in outpatient clinic. Major adverse clinical events (MACE) are carefully monitored. Follow up include immediate postoperative complications.