Wrong-level spinal surgery : a multicentre analysis of 34,544 consecutive cases

Wrong-level spinal surgery (WLSS) is a rare but serious event. Previous studies have been constrained by small sample sizes and voluntary survey methodologies, resulting in variable incidence rates and insufficient data. This study aimed, first, to determine accurately the incidence of WLSS in different regions of the spine; second, to identify high-risk situations and causative mechanisms; and third, to analyze event characteristics in detail, including the timing of recognition, corrective management, and patient-surgeon conflicts. This study was a retrospective analysis of a prospectively collected multicentre registry, involving 34,544 consecutive patients who had undergone spinal surgery for degenerative disorders at 27 affiliated hospitals between January 2012 and December 2022. WLSS data were collected, and lumbar WLSS cases were investigated for method of level identification, causative mechanisms, timing of error recognition, corrective actions, and patient-surgeon conflicts. A total of 40 cases of WLSS were identified, giving an overall incidence of 0.12% (95% CI 0.09 to 0.16). Regional incidence varied significantly: thoracic 0.42% (95% CI 0.16 to 1.08), lumbar 0.13% (95% CI 0.09 to 0.18), and cervical 0.05% (95% CI 0.02 to 0.12; p = 0.004). Of the lumbar procedures, extracanal disc herniation had a significantly higher risk than intracanal herniation (3.41% (95% CI 1.17 to 9.558) vs 0.16% (95% CI 0.07 to 0.35); p < 0.001). Causative mechanisms were categorized as intraoperative disorientation (81.3%) or image misinterpretation (18.8%). Intraoperative disorientation occurred exclusively at levels involving L4/5 or L5/S1. Errors were recognized before patient extubation in 84.4% of cases: all underwent corrective surgery before the reversal of anaesthesia. However, patient-surgeon conflicts still arose in 18.8% of lumbar cases, including 18.5% of those who had undergone reoperation under the same anaesthetic. The incidence of WLSS varies significantly by spinal region, with thoracic surgery and extracanal disc herniation being at highest risk. Intraoperative disorientation, particularly at the lower lumbar levels, was the primary reason. Patient-surgeon conflicts can occur even when errors are recognized and corrected immediately.