Patterns of sural nerve innervation of the sural artery with implication for reconstructive surgery

Abstract Background Most of the literature concerning the neurocutaneous flap is related to its anatomic investigation and clinical application, and the more in-depth physiological problem such as whether the cutaneous nerve contains sympathetic fibers that innervate its accompanying vessels has never been explored. Materials and methods Dissection was first performed on three rabbits. In another 22 rabbits, two rabbits undergoing no surgery were used as the normal control group. In the remaining 20 rabbits, the 40 sides of hind limbs were divided into a nerve severance group, where the sural nerve was transected at its origin after creation of the proximally based sural neurocutaneous flap, and a nerve preservation group, in which the continuation of the sural nerve was preserved. The sural neurovascular bundles at four time points were harvested for immunohistochemical and Western blotting analyses of the expression of tyrosine hydroxylase (TH). An infrared thermal imager was used for measurement of the average flap temperature within the first 24 h. Results The sural neurovascular bundle entered the skin at 4.5 ± 1.2 cm above the lateral malleolus. The TH in the sural nerve and tunica adventitia of the sural artery showed a synchronized abated expression in the nerve severance group. The TH expression showed no decline in the nerve preservation group. The average flap temperature in the nerve severance group was higher than that in the nerve preservation group starting from 2 h after flap harvest ( P = 0.05). Conclusions The cutaneous nerve has meted out sympathetic fibers to the accompanying artery, regulating its vascular tone.