Anatomic basis and clinical application of perforator flap thinning of posterior tibial artery

Objective To explore the anatomic basis of the thinning of the free posterior tibial artery perforator flaps and the clinical effect of repairing wound on hand or foot due to trauma. Methods From November, 2016 to December, 2017, 10 cases of lower extremity cadaver specimens perfused with red ralex were dissected, which were perfused through the amputated femoral artery. Five of them were left and the rest were right. All cases were males. The number, diameter, branches and distribution of the perforator was observed. From September, 2012 to September, 2017, there were 13 cases of clinical application, which were 5 cases of hand wound and 8 cases of foot wound. The size of the wound was 3.0 cm × 2.0 cm to 6.0 cm × 4.0 cm, and the flap area was 3.5 cm × 2.2 cm to 6.5 cm × 4.5 cm. The repairing procedure was suitable for the wound associated with tendon, bone, joint capsule exposure. Results The number of posterior tibial artery perforating branches that more than 0.50 mm in diameter was 4 to 6, and the mean diameter was (0.87±0.26) mm. The perforating branch penetrated into the fat layer and was divided into 3 layers of vascular network: deep fat vascular network, superficial fat vascular network and subdermal vascular network. The perforating branch was located according to the positional relationship from deep to shallow, and vessel diameter become smaller step by step. The perforating branch trunk gave off branches to the deep vascular network, and the superficial vascular network had the same origin or shared with the deep blood vessels. The subdermal vascular network issued from the superficial vascular network or directly from the perforating branch trunk. There was no or few communicating branch between the deep vascular network and superficial ones, besides the vessel pedicle. So trimming deep fat layer will not affect the blood supply of superficial vascular network and neither will affect the flap blood supply. Most of the deep fat tissue was trimmed in 13 cases. The superficial and subdermal fat vascular network was preserved, and the same to the trunk and branches of the pedicle. All the flaps survived. Of which, 1 appeared arterial crisis on the 2nd day after operation, and relieved by the local injection of papaverine. There was 1 case of venous crisis on the 3rd day, and improved by stitches, local release of congestion. Followed-up time was ranged from 2 to 12 months. All flaps were soft with good blood supply and good appearance, and did not need a second thinning surgery. Flaps restored the protective feeling 6 months later. Conclusion The microdissection of perforator flap of posterior tibial artery provides a theoretical basis for the perforator flap thinning, and the thinning of perforator flap is a good method to repair the appearance and function of the wound after foot and hand injuries. Key words: Posterior tibial artery perforator flap; Applied anatomy; Wound; Repair; Microsurgical operation