A new computed-assisted technique for experimental sciatic nerve function analysis

BACKGROUND: Peripheral nerve injury is a well-known experimental tool to evaluate the effect of various neurotrophic substances. Besides histological and electrophysiological techniques, nerve functional status has been assessed by means of the sciatic function index (SFI) and the static sciatic index (SSI). However, these techniques are still based on a complex and old-fashioned apparatus requiring a relatively long time of execution. This study aimed to assess a novel, rapid, computerized method for assessment of SSI in a rat model of sciatic nerve injury. MATERIAL/METHODS: Fourteen rats were used in this study. The left sciatic nerve was exposed and compressed for 2 minutes with an aneurysm clip. Functional evaluation was performed by analysing the footprints of standing rats, comparing the injured to the uninjured limb with the static sciatic index (SSI). For this purpose the rats were placed on a digital scanner and the resulting images were acquired on a personal computer. Analysis was carried out every day after surgery for 21 consecutive days. RESULTS: Two-minute compression of the sciatic nerve produced a major reduction in motor function as assessed by SSI. Improvement was observed by day 7. By day 20, SSI was completely restored. CONCLUSIONS: This technique is simple to use, quick, without expensive technical equipment. It provides good accuracy and precise quantification of the extent of functional loss and recovery after sciatic nerve injury.