Functional assessment of misdirected axon growth after nerve repair in therat

Age, late repair, loss of nerve tissue, tension, and other factors are now known to influence axon regeneration and the quality of recovery after nerv e repair. Many of the factors cannot be controlled by surgery. However, a f ew important ones depend on surgical technique, and some could be minimized , e.g., suture with tension, scarring due to foreign material, and misdirec ted axon growth. In this study, the authors tried to assess the functional consequences of misdirected axon growth in the sciatic nerve of the rat. Th ey used a strainless coaptation nerve-repair technique with bioabsorbable p late support (polylactic acid), permitting them to study only the consequen ces of misdirected axon growth, without tension or suture in the area of ne rve repair. Sixty rats were divided into three groups. In Group 1, 20 sciat ic nerves were repaired without rotation of the distal nerve stump. In Grou p 2, 20 sciatic nerves were repaired with a 90-degree rotation of the dista l nerve stump. In Group 3. 20 sciatic nerves were repaired with a 180-degre e rotation of the distal nerve stump. Functional analyses were performed wi th the sciatic functional index. The results showed the poor consequences of incorrect nerve-end alignment i n nerve repair (p < 0.05). Nerve repair with bioabsorbable plate support is known to allow good stump coaptation, without tension and without foreign material. The authors suggest an adaptation or modification of this techniq ue, which might minimize misdirected axon growth, one of the factors whose effects can be mitigated by surgical technique.