A modification of the neural-island flap: 'split neural-island flap'.

The purpose of this study was to demonstrate the new concept of a consistent and reliable skin-flap design supplied solely by the intrinsic vasculature of a split cutaneous nerve. A total of 88 Wistar rats were used in this experiment, which was divided into three parts. In Part I (n=20), the vascular anatomy and the fascicular anatomy of the lateral femoral cutaneous nerve were established. In Part II (n=44), split neural-island flaps were created. Two skin flaps (measuring 2x3 cm each) were harvested based solely on the lateral femoral cutaneous nerve, which was split into two based on its fascicles. In Part III (n=24), a surgical delay procedure was applied in order to augment the survival areas of split neural-island flaps. On postoperative day 7, the viability of all flaps was evaluated. The results of the anatomic studies demonstrated that the lateral femoral cutaneous nerve consisted of usually two (80%), rarely three, fascicles (20%). Meticulous dissection enabled us to separate these fascicles without disrupting the perineural vasculature around each fascicle. The mean flap survival rate in the acutely elevated split neural-island flap group in Part II was 6.2+/-3.1%, whereas survival in the graft group was 0.0%. Results of Part III of the experiment demonstrated a significantly higher survival rate for the delayed split neural-island flap (98.5+/-2.8%) compared to the acutely elevated split neural-island flap (P<0.05). In conclusion, this is a reliable skin flap that can be nourished solely by the intrinsic vasculature of an interfascicularly dissected ('split') nerve.