2026 Volume 37 Issue 1 Pages 99-105
Background: Restoring intrinsic function is difficult in severe cubital tunnel syndrome (CuTS) with intrinsic muscle palsy. Here we assessed the impact of the supercharge end-to-side anterior interosseous nerve (AIN) to ulnar motor nerve transfer (SETS) on intrinsic muscle function.
Methods: A retrospective evaluation was conducted on 47 patients who had undergone surgery for CuTS. Out of these, 14 patients met specific inclusion criteria: 1) positive Wartenberg’s sign; 2) availability of preoperative nerve conduction studies; and 3) a follow-up period longer than 6 months. The control group consisted of nine patients who underwent ulnar nerve anterior transposition (AT) alone. In comparison, the study group included five patients who received SETS in addition to AT.
Results: The mean age at surgery, palsy duration, preoperative abductor digiti minimi-CMAP amplitude (measured via wrist stimulation), and postoperative follow-up were as follows: for the control group, 60±16 years, 7±8.6 months, 3.6±2.6 mV, and 11±6 months; for the study group, 68±15 years, 6±3.7 months, 1.7±1.8 mV, and 17±6 months. Grip strength increased in both groups: from 73±15.0% to 87±14.8% in the control group and from 79±17.1% to 89±8.4% in the study group, with both changes being statistically significant based on a paired t-test. Wartenberg’s signs were resolved in 66% of the control group patients, but in none of the study group patients. Key pinch strength slightly increased from 61±21.5% to 64±30.4% in the control group — a statistically nonsignificant observation — whereas the study group significantly increased from 58±11.6% to 77±15.5%.
Interpretation: An increase in key pinch strength was observed only after including SETS in elderly patients with severe CuTS, although Wartenberg’s sign remained unchanged. This contradictory outcome might be owing to the anatomical relationship between the AIN and the ulnar nerve, as well as the ulnar nerve’s internal topography at the wrist level.
