Development of a Novel Surgical Method for Endoscopic Flexor Tendon Repair: Stage 0 (Preclinical) Cadaveric Case Report and Study Protocol Following the IDEAL-D Framework

Flexor tendon injuries of the hand are challenging to treat, with open surgical repair causing tissue damage, postoperative edema, and range-of-motion limitations. Minimally invasive endoscopic techniques may address these issues, but no reports describe endoscopic tendon suturing. This IDEAL-D Stage 0 (Preclinical) study presents a cadaveric case report and research protocol for a novel endoscopic flexor tendon repair technique. The case report used the left ring finger of an 88-year-old male cadaver, employing a loop suture technique under endoscopic guidance to visualize and suture tendon ends. Sutures facilitated tendon gliding, withstood 5 N tension, and caused no neurovascular injuries. The protocol involves five cadaver specimens from Fukushima Medical University, excluding those with deformities or prior hand injuries. The primary outcome is the success rate of endoscopic repair, defined as proper tendon alignment, tension, and integrity without complications. Secondary outcomes include suturing time, gap distance, complications, a proposed tendon injury classification system, and a surgical technique video. Results will be analyzed using descriptive statistics with 95% confidence intervals. This technique may offer a minimally invasive, precise solution for flexor tendon injuries.