Ultra minimally invasive sonographically guided carpal tunnel release: an external pilot study.

BACKGROUND: Authors have reported better outcomes, by reducing surgical dissection for carpal tunnel syndromes requiring surgery. Recently, a new sonographically guided technique for ultra minimally invasive (Ultra-MIS) carpal tunnel release (CTR) through 1mm incision has been described.

HYPOTHESIS: We hypothesized that a clinical trial for comparing Ultra-MIS versus Mini-open Carpal Tunnel Release (Mini-OCTR) was feasible.

MATERIALS AND METHODS: To test our hypothesis, we conducted a pilot study for studying Ultra-MIS versus Mini-OCTR respectively performed through a 1mm or a 2 cm incision. We defined success if primary feasibility objectives (safety and efficacy) as well as secondary feasibility objectives (recruitment rates, compliance, completion, treatment blinding, personnel resources and sample size calculation for the clinical trial) could be matched. Score for Quick-DASH questionnaire at final follow-up was studied as the primary variable for the clinical trial. Turnover times were studied for assessing learning curve stability.

RESULTS: Forty patients were allotted. Primary and secondary feasibility objectives were matched with the following occurrences: 70.2% of eligible patients finally recruited; 4.2% of randomization refusals; 26.6 patients/month recruited; 100% patients receiving a blinded treatment; 97.5% compliance and 100% completion. A sample size of 91 patients was calculated for clinical trial validation. At final follow-up, preliminary results for Quick-Dash substantially favored Ultra-MIS over Mini-OCTR (average 14.54 versus 7.39) and complication rates were lower for Ultra-MIS (5% versus 20%). A stable learning curve was observed for both groups.

CONCLUSIONS: The clinical trial is feasible. There is currently no evidence to contraindicate nor withhold the use of Ultra-MIS for CTR.

LEVEL OF EVIDENCE: III.