Recovery and Regrowth After Nerve Repair: A Systematic Analysis of Four Repair Techniques.

BACKGROUND:Outcome assessments that evaluate post-transection nerve repair do not often correlate with one another. The aims of this study were twofold: to compare four nerve repair techniques with each other and incorporate both negative and positive control groups and to identify possible correlations between outcome assessments. MATERIALS AND METHODS:Sciatic nerve transection and repair was performed in Lewis rats using one of the following techniques: interrupted epineural, running epineural, grouped fascicular, epineural with absorbable type I collagen wrap, and high tension for incorporation of a negative control. A sham surgery group was also included as a positive control group. Outcomes were compared using assessments of functional recovery (behavior and electrophysiology) and nerve regrowth (imaging and histomorphometry). Three-dimensional printed custom electrode stabilization and imaging devices were designed and fabricated to provide standardization in assessment between subjects. RESULTS:Nerve repair was performed in 48 male Lewis rats. In all animals, functional testing was performed at week 13. The sham group (n = 7) performed the best on both behavioral assays (P < 0.001) and electrophysiology assessments (P < 0.001). The negative control group (high tension) performed poorest on multiple assessments, and there were no significant differences observed for any of the four repair types. Positive correlations were observed between behavioral and histomorphometric tests. CONCLUSIONS:There was no difference in outcome between the four types of nerve repair. High-tension nerve repair represents an ideal negative control. Not all assessment methods correlate equally, and consistent use of complimentary outcome assessments could allow for improved comparison between studies.