Free extended posterior tibial artery perforator flap with the neurovascular plexus of a saphenous nerve branch for large soft tissue and sensory reconstruction: Anatomic study and clinical application

Background The posterior tibial artery perforator (PTAP) flap is a useful tool for reconstruction of soft tissue defects in the leg. However, the size and reliability of the flap largely depends on the quality of the perforator by which the flap is supplied, and the sensory recovery of the flap is limited. In this study, the anatomy of the saphenous nerve branches and their accompanying vessels was investigated, and a free extended PTAP flap with the neurovascular plexus of a saphenous nerve branch was designed for large soft tissue and sensory reconstruction in a series of clinical cases. Methods Sixteen adult cadaveric legs perfused with red latex in the femoral artery were dissected. The number and location of the saphenous nerve branches and the features of their accompanying vessels were dissected and studied. From January 2016 to December 2017, six patients with soft tissue defects ranged from 8 × 2.5 cm to 21 × 4 cm were repaired by the free extended PTAP flap. The patients' average age was 48 years. The causes of the defects included machine injuries in three patients and traffic injuries in the other three. The defects located at the hand in three cases, foot in two cases, and ankle in one case. The flap was designed based on the perforators of the posterior tibial artery and included a branch of saphenous nerve. The perforator pedicle and the nerve branch were connected to the vessels and nerve in the recipient site, respectively. Results The saphenous nerve gave off 5.8 ± 1.1 branches, with a relatively constant one issuing 8.1 ± 0.7 cm distal to the medial femoral condyle. Every nerve branch had an accompanying vessel, which connected with the PTAPs and supplied the skin. The size of the flap ranged from 10 × 3.5 cm to 23 × 5 cm. All of the flaps survived completely without complications. Follow-up varied from 6 to 12 months. All the patients obtained cold/hot sensation and pain sensation. The results of Semmes-Weinstein monofilament test ranged from 4.31(2 g) to 5.46 (26 g), and the 2-point discrimination test varied from 20 to 35 mm. Conclusion The free extended PTAP flap, containing the saphenous nerve branch and its accompanying vessels, may be an alternative for large soft tissue reconstruction with improved sensation recovery.