Does vascularized adipose tissue enhance nerve regeneration?

Background. The use of adipose tissue in reconstructive procedures has become popular in the last decades due to the adipose tissue properties of stem cells and mechanical protection. In acute nerve lesions, there have been experimental reports on the use of non-vascularised adipose tissue as an adjuvant for nerve recovery but to our knowledge there is no published research that describes the effect of the pedicled vascularised adipose tissue (pVAT) on acute nerve injuries. Therefore we decided to study the effect of pVAT on nerve regeneration when wrapped around an epineurial coaptation site and for a 5 mm defect of the sciatic nerve from the rat. Methods. The effect of pedicled vascularized adipose tissue (pVAT) on nerve regeneration was studied on the sciatic nerve injury model in twenty-four Wistar rats divided into four groups: epineurial repair; epineurial repair and pVAT; a 5 mm nerve gap bridged by an autograft; a 5 mm nerve gap bridged by a conduit-pVAT (C-pVAT). Automatization injuries, walking track analysis, postoperative extraneural fibrosis and histological analysis were performed three months after the intervention. Results. Although histological and functional nerve regeneration was present in various degrees in all the studied groups, nerve regeneration was not enhanced by the use of the pVAT or C-pVAT. The harvesting of the pVAT flap caused postoperative fibrosis when used as a conduit. Automutilation was not decreased by the use of the pVAT nor a correlation between automutilation and postoperative fibrosis in the studied groups could be established. The postoperative fibrosis did not influence neural regeneration in the pVAT and autograft group. Conclusion. Vascularized adipose tissue did not enhance neural regeneration when used as an adjunct procedure for primary nerve repair and or even as a novel conduit for 5 mm nerve defects in the rat sciatic nerve.