Ulnar nerve decompression and transposition with versus without supercharged end-to-side motor nerve transfer for advanced cubital tunnel syndrome: a randomized comparison study

OBJECTIVE The objective of this prospective randomized study was to compare ulnar nerve decompression and anterior subfascial transposition with versus without supercharged end-to-side anterior interosseous nerve-to-ulnar motor nerve transfer for advanced cubital tunnel syndrome, to describe performing the nerve transfer through a small incision, and to investigate predictive factors for poor recovery following the procedure. METHODS Between January 2013 and October 2016, 93 patients were randomly allocated to a study group (n = 45) and a control group (n = 48). Patients in the study group were treated with supercharged motor nerve transfer via a 5- cm incision following decompression and anterior subfascial transposition. Patients in the control group were treated with decompression and anterior subfascial transposition alone. Postoperative pinch strength and compound muscle action potential amplitude (CMAPa) were assessed. Function of the limb was assessed based on the Gabel/Amadio scale. Between- group data were compared, and significance was set at p < 0.05. Potential risk factors were collected from demographic data and disease severity indicators. RESULTS At the final follow-up at 2 years, the results of the study group were superior to those of the control group with regard to postoperative pinch strength ( 75.13% +/- 7.65% vs 62.11% +/- 6.97%, p < 0.05); CMAPa of the first dorsal interossei (17.17 +/- 5.84 mV vs 12.20 +/- 4.09 mV, p < 0.01); CMAPa of abductor digiti minimi (11.57 +/- 4.04 mV vs 8.43 +/- 6.11 mV, p < 0.01); and excellent to good results (0.67 for the study group vs 0.35 for the control group, p < 0.05). Multivariate analysis showed that the advanced age (OR 2.98, 95% CI 2.25-4.10; p = 0.003) in the study group was related to unsatisfactory outcome in the patients. CONCLUSIONS In the treatment of advanced cubital tunnel syndrome, additional supercharged end-to-side anterior interosseous nerve- to-ulnar motor nerve transfer may produce a better function of the hand. The authors also found that cases in the elderly were related to unsatisfactory postoperative results for these patients and that they could be informed of the possibility of worsening surgery results.