Summary

Despite lack of consensus on diagnosis and appropriate management of symptomatic CuTS, this study found that cases of mild and moderate CuTS that are electrodiagnostically severe have greater odds of being surgically treated.

Abstract

Introduction

Previous studies demonstrate a significant increase in surgical procedures aimed to treat cubital tunnel syndrome (CuTS) over the last 25 years despite lack of consensus on diagnosis and appropriate management of symptomatic CuTS. This is particularly true in patients who present predominantly with subjective symptoms rather than persistent numbness or intrinsic atrophy. This study aimed to investigate the demographic and clinical differences between surgical and non-surgical treatment of patients with mild or moderate CuTS.

Methods

To control for variance due to surgeon preferences, data were retrospectively reviewed from a single-institution orthopedic practice from December 2016 to July 2022. A random sample of patients were included if they were diagnosed with mild or moderate (McGowan Grade I or II, respectively) CuTS and underwent concurrent electrodiagnostic (EDx) and ultrasound (US) evaluations.
Patient demographics, symptom presentation, clinical findings, and diagnostic test findings were analyzed. Continuous variables were analyzed using Student’s t-test or Mann-Whitney U-Test. Categorical variables were analyzed by Pearson’s X2 or Fisher’s Exact test. Multivariable logistic regression models were used to test the association of factors associated with surgical intervention.

Results

The sample consisted of 73 patients and 103 elbows aged 18-84. Most patients were male, right-hand dominant, and unilaterally symptomatic in the dominant hand (Table 1). Twenty-six elbows were surgically treated. Bivariable analyses by surgical treatment showed that patients who underwent surgery more often had positive electrodiagnostic findings including motor nerve conduction velocity (CVm) <50m/s and CVm difference >10m/s.
Fifty-nine cases were categorized as electrodiagnostically normal, 31 as mild-moderate, and 13 as severe. Of the electrodiagnostically normal cases 29 had positive findings of CuTS on US. Cases involving the non-dominant hand were more often severe. Abnormalities on US defined as nerve enlargement or segmental thickening were more often noted among mild-moderate and severe cases and equally in normal cases. Normal cases were mostly found with UN CSA of 4.9-9.7mm2 while severe cases were mostly found with UN CSA of 14-34mm2 (Table 2).
Our logistic regression model showed that electrodiagnostically severe cases had 3.7 times higher odds of being surgically treated than their normal counterparts (AOR: 3.7, 95%CI: 1.11-12.6; p=0.03).

Discussion

Only electrodiagnostic severity differentiated patients that were treated surgically from those who were treated conservatively for mild to moderate CuTS symptoms. Future studies should continue to investigate factors influencing surgical treatment of these patients including self-reported level of impairment.