Superficial Versus Deep Local Anesthetic Infiltration in Carpal Tunnel Release: A Randomized Clinical Trial

Carpal tunnel release (CTR) is commonly performed with the patient wide awake using local anesthetic (LA). Although most patients tolerate this type of procedure, there is a possibility of some discomfort or pain. We compared two LA infiltration techniques-subcutaneous infiltration alone (superficial) and subcutaneous infiltration with infiltration into the carpal tunnel (deep)-to determine which provides a better pain experience during CTR.

Seventy-four participants (n = 80 cases) were recruited and randomized to either deep or superficial LA infiltration. Thirty-eight received deep LA and 42 superficial LA. Primary outcomes were presence and severity of pain and/or tingling during the LA infiltration and during the procedure. We also examined the severity of pain at 2, 8, and 24 hours after the procedure. Clinical outcomes were assessed with the Boston Carpal Tunnel Questionnaire score at baseline and at 3 months postprocedure. Statistical comparisons were performed using chi-square and analysis of variance tests.

The average age of participants was 63.04 ± 12.92 years (n = 40 females and n = 34 males). In the deep group, 21% experienced pain during LA infiltration compared to 9.5% in the superficial group, whereas 13.2% of the deep group and 11.0% of the superficial group experienced pain during the procedure. Both groups showed a significant improvement in clinical outcomes, measured by the Boston Carpal Tunnel Questionnaire.

In this randomized clinical trial comparing deep versus superficial LA infiltration techniques for CTR, we found that there was no statistically significant difference in the pain experienced during the administration of the LA or during the procedure. Given these findings, we recommend using superficial infiltration for CTR as it is technically easier and reduces the risk of potential median nerve injury.

Therapeutic Ib.