Evaluation of outcome after primary median and/or ulnar nerve(s) repair at wrist: clinical, functional, electrophysiologic, and ultrasound study

Background A major problem in surgery of peripheral nerve injuries of the upper extremities is the unpredictable final outcome. More insight and understanding of the proper methods of outcome assessment and the prognostic factors is necessary to improve functional outcome after repair of peripheral nerves. The objective of this study is to assess the outcome and identify possible prognostic factors for functional recovery of median and/or ulnar nerves repairs at wrist. Forty patients with median, ulnar or combined median-ulnar nerve injuries were included. Smoking, age, sex, repaired nerve, associated artery and/ or tendon repairs, joint stiffness and scar tissue were analyzed as prognostic factors for functional outcome after repair. Outcome parameters were medical research counsel (MRC) scoring for sensory and motor recovery, grip and pinch strength, disability of arm, shoulder and hand (DASH) questionnaire, electrophysiology and ultrasonographic evaluation. Results The mean age of the studied patients was 29.1 ± 8.3 and it was statistically correlated with grip strength ( p = 0.045), DASH score ( p = 0.046) and hyperesthesia score ( p = 0.040). EMG results showed signs of regeneration in all patients in the form of small nascent MUAPs and polyphasic MUAPs. CMAP amplitudes of median and ulnar nerves positively correlated with the MRC scale for muscle strength ( p = 0.001) There were statistically significant negative correlations between DASH score and MRC score for sensory evaluation ( p = 0.016), grip ( p = 0.001), and pinch strength ( p = 0.001). There were statistically significant positive correlations between patient's opinion of recovery and MRC score for sensory evaluation ( p = 0.029), grip ( p = 0.001), and pinch strength ( p = 0.001). The MRC score for muscle strength has statistical significant positive correlations with the MRC score for sensory evaluation, grip ( p = 0.003), and pinch strength ( p = 0.040) Conclusions It was concluded that; MRC scale for muscle power, MRC scale for sensory evaluation, functional scores, grip and pinch strength are valuable tools for evaluation of functional outcome. Age, smoking, associated tendon repair, damaged nerve, compliance to rehabilitation protocol, return to work, clinically visible wound adhesions, residual hand joint stiffness, and scar tissue detected by ultrasound were found to be prognostic factors for outcome after nerve repair.