A comparison of nerve grafting and tissue expansion techniques in the rat

This study compares nerve repair following tissue expansion with nerve repair using an interposed graft in the rat. Group I had expansion conducted over 2 weeks at 40 mmHg. A 4 mm segment was excised from the lengthened nerve and repaired primarily. Group II had a 4 mm segment of nerve excised and then replaced as an interposition graft. Group III was sham-operated controls. Thirteen weeks postoperatively, all animals were evaluated using walking track analysis. Thirty-five rats finished the study: Eleven in group I, 10 in group II, and 14 in group III. The Sciatic Functional Index (SFI) was calculated for each group as follows: group I, -57 +/- 11 (mean +/- standard deviation); group II, -59 +/- 25; group III, -13 +/- 6.5. The control group was significantly better than either experimental group (P < 0.01). The two experimental groups were not statistically different. Nerve repair following expansion allowed only one coaptation to be used. Functional results were the same as with interposition grafting. Repair by the expansion technique would eliminate the need to harvest a nerve graft, and the subsequent donor defect.