Correlation Analysis of Histomorphometry and Motor Neurography in the Median Nerve Rat Model

Objective: Standard methods to evaluate the functional regeneration after injury of the rat median nerve are insufficient to identify any further differences of axonal nerve regeneration after restitution of motor recovery is completed. An important complementary method for assessing such differences is a histomorphometric analysis of the distal to lesion nerve fibers. Recently, an electrophysiological method has been proposed as a sensitive method to examine the quality of axonal nerve regeneration. Methods: A linear regression analysis has been performed to correlate histomorphometric and neurographic data originating from 31 rats subjected to neurotmesis and immediate reconstruction of their right median nerve. Results: A significant linear correlation between the velocity of neuromuscular conduction and the total number of nerve fibers (P = .037) as well as between the amplitude of compound muscle action potential and the total number of nerve fibers (P = .026) has been identified. Interestingly, a significant correlation between the velocity of neuromuscular conduction and the square root of the cross-sectional area of the nerve could be found (P = .008). This corresponds to a linear correlation between the velocity of neuromuscular conduction and the radius of the nerve. Conclusion: These results contribute in a better interpretation of morphological predictors of nerve regeneration and verify the previously described electrophysiological assessment in the median nerve rat model as a valid method.