A functional model of nerve repair. Reanastomosis vs entubulation repair.

OBJECTIVE: To compare reanastomosis and entubulation repair after transection of the peroneal nerve in rats with the use of 2 functional models: gait analysis and a tension transduction device. DESIGN: Prospective, randomized, blinded control study. Each animal served as its own control. The injured site was alternated between the left and the right. Gait analysis was evaluated in a blind fashion at postoperative weeks 1, 3, 7, and 13, and the tension transduction device at week 13, for injured and uninjured legs. SUBJECTS: Animals underwent unilateral peroneal nerve transection injury, half with entubulation and half with end-to-end reanastomosis repair. INTERVENTION: Nerve transection was performed 6 mm proximal to the anterior tibialis muscle insertion followed by reanastomosis (epineurial suture placement to align the sectioned nerve ends) or entubulation (placement of nerve ends into a 4-mm-long sterile Silastic tube secured with 2 epineurial sutures). RESULTS: Gait analysis demonstrated a poorer ankle angle in all injured legs compared with uninjured legs at each postoperative period. Ankle angles for reanastomosis were statistically better than those for entubulation at weeks 3, 7, and 13. The tension transduction device demonstrated poorer force in injured than uninjured animals at 13 weeks. Reanastomosis repair groups demonstrated no difference in force development compared with entubulation repair groups. CONCLUSIONS: Reanastomosis of the transected rat peroneal nerve demonstrated improved functional return by gait analysis when compared with entubulation-repaired nerves at postoperative weeks 3, 7, and 13. Force development of injured nerve groups measured by the tension transduction device was decreased compared with control, but no difference was detected between the 2 repair methods. Further studies are needed to evaluate the possible functional benefit of reanastomosis.

Brain-derived neurotrophic factor and peripheral nerve regeneration: a functional evaluation.

The potential benefit of brain-derived neurotrophic factor (BDNF) on motor-nerve regeneration after transection injury in 24 adult rats was evaluated after entubulation repair. Gait analysis for ankle angle and tension transduction device (TTD) strain-gauge measurements yielded functional evaluation of regeneration. The BDNF (15 mg/mL) or phosphate buffered saline (control) was injected into the silicone elastomer (Silastic) channel. Gait analysis performed 0, 2, 4, 6, 10, and 12 weeks after injury demonstrated a significant difference between uninjured and injured legs of 23 and 43 degrees, respectively (P<.001, analysis of variance). The TTD evaluation 13 weeks after injury demonstrated a significant decrease in force development of injured compared to uninjured legs, 148 and 58 g, respectively (P<.001). No functional benefits were demonstrated between BDNF-treated versus control-treated animals in either model for a single exposure to BDNF.