The rate of bursting strength gain in repaired nerves

The sciatic nerve in 60 rats was transected and repaired with 9-0 nylon under magnification. The repairs were tested for bursting strength at 2, 3, 6, 9, and 12 weeks and expressed as a percentage of the bursting strength of a paired control from the opposite leg. The mean percent bursting strength was 25, 42, 53, 45, and 62, respectively. There was no statistically significant gain in bursting strength from the third to the ninth week after nerve repair. However, there was a significant difference in bursting strength at 3 weeks and 12 weeks after repair. A similar experiment was performed in monkeys. At 4 weeks, the repaired nerves had regained 77% of the bursting strength of the normal median and ulnar nerves. These studies call into question earlier claims that repaired nerves regain normal bursting strength within 3 to 4 weeks of repair.