Inside-out and Standard Vein Grafts, with or without Muscle Filling, in Peripheral Nerve Repair: A Histomorphometric Study

Abstract

Aim: The aim of this study was to compare two tubulization techniques, inside-out veins and standard veins, both filled with skeletal muscle or not, in sciatic nerve by morphological and histomorphometric study. Methodology: Seventy Wistar rats were divided in 4 experimental groups (IOVNF - inside-out vein with no filling; IOVSM - inside-out vein filled with skeletal muscle; SVNF - standard vein with no filling; and SVSM - standard vein filled with skeletal muscle) and a control group (Sham). The left external jugular vein was sectioned into about 14 mm segments to be used as autologous vein grafts. A 10 mm gap was then created in the sciatic nerve and the vein graft was inserted into the vein with or without filling of the right caudal tibial muscle. The animals were euthanized 12 weeks after surgery. Results: Myelinated and unmyelinated nerve fibers were observed in the histological analyses for all groups, as well as neoformation of the perineurium and intraneural organization of fascicles and blood vessels. In the morphometric analysis of the distal stump, regarding the myelin sheath area, all groups had a significant difference. The IOVNF group had the highest means for fiber, axon and myelin sheath areas. The SVSM group had the lowest means in all features measured, except for the axon area (4.95±1.72 graft; 3.71±0.90 distal stump). Conclusion: These results show that sciatic nerve repair with inside-out veins and no filling (IOVNF) had the best results, in the majority of measured variables, when compared to the other groups.