A new epineural nerve repair technique: oblique nerve coaptation.

Despite the existence of various nerve coaptation techniques, functional results of nerve repair are still inadequate. Potential benefits of developing modified coaptation techniques cannot be disregarded. The authors report a new coaptation technique in which the nerves are cut in an oblique fashion to increase the coaptational surface. The sciatic nerves of male Wistar albino rats were cut at an angle of 30 and 45 deg (experimental groups), and 90 deg (control group). The nerves were repaired with nine 10-0 epineural stitches. Functional and histological studies were performed at week 12 on 7 rats from the 30-deg group, 15 rats from the 45-deg group, and 7 rats from the 90-deg group. Mean sciatic function index values of walking track analysis were the following: 30-deg group, -42.4+/-15.4; 45-deg group, -44.7+/-17.9; and 90-deg group, -52.9+/-13.9 (p>0.05). The mean values of myelinated axonal counts for the 30-deg, 45-deg, and 90-deg transection groups were 196.2+/-3.7, 196.1+/- 3.7, and 176.1+/- 5.6 respectively for proximal nerve segments and 180.1+/-6.8, 178.2+/-3.8, and 114.1+/-17.3 respectively for distal samples. Both the 30-deg and 45-deg coaptational groups had a significantly lower reduction of myelinated axonal counts at the regeneration zone in comparison with the 90-deg group (p<0.01). Mean myelinated axonal diameters in the proximal nerve segments were 8.2+/-2.6 microm, 8.4+/-3.1 microm, and 8.1+/-3.2 microm respectively, and were 7.1+/-3.6 microm, 6.9+/-3.4 microm, and 6.7+/-3.4 microm respectively in the distal nerve segments (p>0.05). The oblique nerve coaptation technique may enhance nerve regeneration by enabling a larger sprouting and contact area for nerve fibers, but additional investigation by more experienced centers is needed before relying on the preliminary results of this simple modification.