Abstract
Hypothesis
Does the result of steroid injection in the carpal tunnel in a patient with recurrent carpal tunnel symptoms provide a good predictor of the outcome of later carpal tunnel release (CTR).
Methods
A retrospective review of all patients who underwent revision CTR for recurrent or persistent carpal tunnel syndrome (CTS) over a two year period was conducted. A total of 23 patients and 28 wrists met inclusion criteria. Patients were evaluated to determine if pre-operative factors or result of injection predicted the outcome of revision CTR. A multivariate logistic regression analysis (MLRA) was used to predict surgical success when multiple pre-operative findings were considered.
Results
No patient characteristic or physical exam finding was found to predict successful revision CTR. Twenty-two (86.4%) of patients who had relief from injection had symptom relief/improvement with revision CTR whereas only 4 (13.6%) were not improved by the surgery; the difference was not statistically significant. The sensitivity and positive predictive value for injection alone predicting outcome of revision CTR was 86.4%. MLRA combining injection results with physical exam findings (Numbness and/or motor weakness in median nerve distribution, Positive Durkin's, and Positive Phalen's test) provided a sensitivity of 100% and specificity of 80%.
Conclusions
In contrast to primary CTS, cortisone injection into the carpal tunnel in the face of recurrent CTS is not, by itself, a statistically significant predictor of successful revision surgery. However, patients with a positive result from injection had an 86.4% success with revision CTR with an average DASH score of 28.87. Relief from injection as a diagnostic test for success from revision CTR was found to have both high sensitivity and positive predictive value. Coupled with the components of the physical examination, injection provides a good screening test to establish success with revision CTR, sensitivity of 100% and specificity of 80%
