Study: Revision cubital tunnel surgery provides improvement, but poor results vs primary surgery

BOSTON — A cross-sectional study that compared patients with at least 2 years of follow-up who underwent primary surgery of the ulnar nerve for cubital tunnel syndrome to a group that underwent revision showed poorer objective and patient-reported outcomes in the revision cohort.

“The findings of our study indicate that the outcomes of revision ulnar nerve surgery for cubital tunnel fail to replicate the outcomes of primary nerve surgery,” Alexander Aleem, MD, said at the American Society for Surgery of the Hand Annual Meeting, here. “There are multiple plausible explanations for this discrepancy. Revision surgery may add a second traumatic insult to the nerve that makes it more difficult to recover function. This group of patients may have an inherent nerve dysfunction that is not amenable to recover regardless of surgical treatment. Additionally, the added morbidity of submuscular transposition may contribute to this disparity.”

Researchers investigated the results of patients who were at least 2 years after primary or revision surgery and had returned for an in-office evaluation. The primary outcome measure for the study was the Levine-Katz Questionnaire. A power analysis revealed 40 patients would be needed per group to indicate a minimal clinical difference, Aleem said.

Of the 51 revision and 448 primary patients eligible for the study, 28 revision patients agreed to participate and 28 randomly selected control patients who only underwent one surgery, irrespective of outcome, were included.

The groups had similar symptom length, quality of preoperative symptoms, preoperative motor conduction velocity and preoperative disease severity, as measured by McGowan grade.

“Ninety-three percent of the revision group had open in situ decompression as their primary surgery compared to 61% in the control group. This was statistically significant,” Aleem said noting that most of the revision surgeries performed were submuscular transpositions.

Patient-rated outcomes taken during the in-office evaluation showed the control group demonstrated both statistically significant and clinically relevant favorable outcomes when compared to the revision group for all scores. In addition, 96% of the control patients reported permanent or temporary relief after their primary surgery compared to 50% of the revision group. Overall, 79% of the revision group reported relief after their revision surgery.

“On physical exam, the revision group was found to have significant differences, with worse outcomes in elbow extension, ulnar nerve tenderness, pinch strength, two-point discrimination and the presence of a Wartenberg’s sign,” Aleem said.

Final postoperative McGowan grading showed 79% of the control group were grade 0 or 1 vs. 39% of the revision group. More than half of the revision group showed no change in their grading; 25% showed improvement in their grading and 21% had worse function post-revision.

Aleem said potential recall and selection bias, retrospective design and small enrollment as study limitations.

“Revision cubital tunnel surgery still provides a subjective improvement, as 80% of the patients in our study claimed,” he said. “However, patients are still expected to have continued nerve dysfunction and we counsel them regarding this when discussing revision surgery.” – by Gina Brockenbrough, MA

Reference:

Aleem A. Paper #41. Presented at: American Society for Surgery of the Hand Annual Meeting; Sept. 18-20, 2014; Boston.

Disclosure: Aleem has no relevant financial disclosures.