A Mechanism-Based Classification and Review of Endoscopic and Ultrasound-Guided Carpal Tunnel Release.

Background

Minimally invasive carpal tunnel release (CTR) approaches, including endoscopic and ultrasound-guided, encompass a range of distinct techniques. These approaches have been increasingly adopted across both surgical and non-surgical specialties. However, the literature frequently groups the techniques into broad categories, obscuring clinically meaningful differences in transection mechanism, safety profile, and learning curve.

Methods

This narrative review organizes minimally invasive CTR into eight distinct techniques, two endoscopic and six ultrasound-guided, classified by their primary transection mechanism.

Results

Single-portal endoscopic CTR has the largest evidence base, with network meta-analysis data demonstrating significant early functional advantages over open CTR. Among ultrasound-guided techniques, the retractable retrograde blade is the most widely adopted, with randomized trial data supporting comparable outcomes to mini-open CTR. Hook-knife retrograde and thread-loop techniques have demonstrated feasibility and durable outcomes, though experience is concentrated among a few high-volume operators. The antegrade cutting, pinhole scalpel, and needle-knife have more limited evidence. Earlier return to work is the most reproducible benefit across all minimally invasive approaches. Endoscopic CTR carries a modestly higher revision rate, while long-term data for ultrasound-guided techniques remain lacking.

Conclusions

This mechanism-based classification highlights important differences between techniques in safety features, evidence maturity, and learning curves. Head-to-head trials comparing endoscopic and ultrasound-guided techniques and device-specific registries with standardized outcome reporting are needed to inform evidence-based adoption.