Safety and efficacy of the “safe needle” technique in single-portal endoscopic carpal tunnel release for carpal tunnel syndrome: a case series report

To assess the safety of the “Safe Needle” assistive technique for preventing iatrogenic superficial palmar arch (SPA) injury during single‑portal endoscopic carpal tunnel release (SECTR), and to report secondary clinical outcomes. This single‑center retrospective case series included 100 patients with carpal tunnel syndrome (CTS) who underwent Safe‑Needle‑assisted SECTR from October 2023 to June 2025. The key procedural step was preoperative high‑frequency ultrasound localization of the SPA apex. A sterile 5‑mL syringe needle was percutaneously inserted vertically 1.0 cm proximal to this apex to create a visible and palpable physical barrier as a mechanical stop deep beneath the transverse carpal ligament (TCL). The primary outcome was the incidence of intra‑ or postoperative SPA‑related injury. Secondary outcomes comprised operative time, complication rates, CTS‑6 scores, pillar‑pain Visual Analog Scale (VAS) scores, and patient‑reported satisfaction. Mean follow‑up duration was 13.2 ± 2.8 months. No iatrogenic SPA injuries were observed across the entire cohort (0%). The overall complication rate was 3.0%, including two cases of mild pillar pain resolving spontaneously within 3 months and one case of complex regional pain syndrome (CRPS). No permanent nerve or tendon injuries occurred. Mean operative time per wrist was 16.2 ± 2.5 min. At final follow‑up, median CTS‑6 scores decreased significantly from 15.0 preoperatively to 6.0 (*P* < 0.001), corresponding to an 84.0% clinical recovery rate; mean patient satisfaction was 6.2 ± 0.9 points. The Safe Needle technique establishes a physical barrier to overcome poorly defined distal cutting borders of the TCL within the endoscopic anatomical blind spot. This simple, low‑cost safety adjunct prevents SPA injury without prolonging operative time or increasing medical expenses. It may be recommended for SECTR clinical training and routine practice to improve intraoperative safety.