微細手術用縫合針のX線検出限界：人体死体モデルを用いた評価

Intraoperative loss of surgical needles represents a rare but significant challenge in operative settings, particularly in microsurgical procedures involving free tissue transfer where fine sutures (8-0 to 10-0) are employed. Current hospital protocols typically use intraoperative portable radiography to localize misplaced needles. However, the diagnostic utility of X-ray imaging in detecting small-caliber needles remains poorly defined. Following ethical approval, a cadaveric study was conducted using a range of monofilament Ethilon™ needles (3-0 to 10-0 caliber), which were inserted at four anatomically relevant surgical sites. Anteroposterior radiographs were obtained using a standard intraoperative C-arm. A total of 53 participants - including consultant surgeons, radiology trainees, nursing staff, and surgical registrars-were asked to identify needle number and location using blinded image review. Radiographic identification of needles was accurate for calibers 3-0, 4-0, 5-0, and 6-0, with identification rates approaching or exceeding 99%. Smaller needle calibers showed a dramatic decline in detection accuracy. The 8-0 needles were correctly localized in 3.77% of attempts, just one 9-0 needle was successfully identified. None of the 10-0 needles were detected across all anatomical sites. While portable radiography remains a reliable modality for locating surgical needles of caliber 3-0 to 6-0, it proves ineffective for the detection of finer microsurgical needles (≥8-0). These results have important implications for operative protocols and clinical decision-making. The routine X-ray imaging in cases of microsurgical needle loss warrants reconsideration to favor evidence-informed strategies that minimize intraoperative delays, prolonged anesthesia and unnecessary radiation exposure.