title: Delayed repair of the peripheral nerve: a novel model in the rat sciatic nerve.
abstract: Peripheral nerve reconstruction is seldom done in the acute phase of nerve injury due to concomitant injuries and the uncertainty of the extent of nerve damage. A proper model that mimics true clinical scenarios is critical but lacking. The aim of this study is to develop a standardized, delayed sciatic nerve repair model in rats and validate the feasibility of direct secondary neurrorraphy after various delay intervals. Immediately or 1, 4, 6, 8 and 12 weeks after sciatic nerve transection, nerve repair was carried out. A successful tension-free direct neurorraphy (TFDN) was defined when the gap was shorter than 4.0 mm and the stumps could be reapproximated with 10-0 stitches without detachment. Compound muscle action potential (CMAP) was recorded postoperatively. Gaps between the two nerve stumps ranged from 0 to 9 mm, the average being 1.36, 2.85, 3.43, 3.83 and 6.4 mm in rats with 1, 4, 6, 8 and 12 week delay, respectively. The rate of successful TFDN was 78% overall. CMAP values of 1 and 4 week delay groups were not different from the immediate repair group, whereas CMAP amplitudes of 6, 8 and 12 week delay groups were significantly lower. A novel, standardized delayed nerve repair model is established. For this model to be sensitive, the interval between nerve injury and secondary repair should be at least over 4 weeks. Thereafter the longer the delay, the more challenging the model is for nerve regeneration. The choice of delay intervals can be tailored to meet specific requirements in future studies.
authors: Department of Neurologic Surgery, Mayo Clinic, Rochester, MN 55905, USA.
authors: Peng
authors: P
authors: Wu
authors: Robert J
authors: RJ
authors: Spinner
authors: Yudong
authors: Y
authors: Gu
authors: Michael J
authors: MJ
authors: Yaszemski
authors: Anthony J
authors: AJ
authors: Windebank
authors: Huan
authors: H
authors: Wang
mesh_terms: D000200:Action Potentials; D000818:Animals; D019771:Axotomy; D005240:Feasibility Studies; D005260:Female; D008866:Microsurgery / Q000379:methods; D009416:Nerve Regeneration; D019635:Neurosurgical Procedures / Q000379:methods*; D051381:Rats; D011917:Rats, Inbred Lew; D012086:Reoperation; D015203:Reproducibility of Results; D012584:Sciatic Nerve / Q000293:injuries / Q000502:physiology / Q000601:surgery*; D013997:Time Factors