Crush Nerve Injury Model in the Rat Sciatic Nerve: A Comprehensive Review and Validation of Various Methods.

INTRODUCTION The rat sciatic nerve crush injury model is commonly employed to evaluate the efficacy of treatments aimed at promoting nerve regeneration. This review examines various crush techniques and the types of nerve injuries they are designed to produce. METHODS A literature review was conducted using PubMed, Embase, Web of Science, and SCOPUS for studies published between 2010 and 2024. Studies were included if they involved surgical crush injuries on the rat sciatic nerve, performed at least one sensory functional evaluation, and compared outcomes with naive or sham controls. Crush techniques and the resulting nerve injuries were analyzed based on postoperative sensory evaluations. RESULTS Of the 48 studies reviewed, 21 met the inclusion criteria. The crush techniques used included clamp (11 studies), forceps (5), clip (4), and others (1), all of which resulted in sensory impairments. Ten studies reported transient impairments with recovery to control levels, while 11 reported no recovery during the observation period (permanent). The transient group had significantly longer observation periods compared to the permanent group (57.7 vs. 17.4 days, p = 0.0009). ROC analysis determined 25 days as the optimal cutoff to distinguish transient from permanent injuries, with 90.0% sensitivity and 81.8% specificity. DISCUSSION Regardless of the technique used, the induced nerve injury aligns with axonotmesis, characterized by spontaneous recovery over time. To accurately evaluate functional recovery, a minimum postoperative observation period of 4 weeks is recommended. This model is best suited for assessing rapid-acting agents, as spontaneous recovery may obscure the effects of slower-acting treatments.