{"title":"How many cases of spinal intramedullary ependymoma surgery are required to achieve stability? - Analysis using X-bar charts.","authors":"Narihito Nagoshi, Kengo Nagashima, Toshiki Okubo, Masahiro Ozaki, Satoshi Suzuki, Kazuki Takeda, Takahito Iga, Morio Matsumoto, Masaya Nakamura, Kota Watanabe","doi":"10.1038/s41393-025-01090-0","DOIUrl":null,"url":null,"abstract":"<p><strong>Study design: </strong>Retrospective cohort study.</p><p><strong>Objectives: </strong>To evaluate surgical consistency and clinical outcomes in intramedullary ependymoma (WHO grade II) cases by using X-bar charts as a tool to assess procedural stability.</p><p><strong>Setting: </strong>The single institution in Japan.</p><p><strong>Methods: </strong>This study included patients who underwent resection of intramedullary ependymomas between 2001 and 2023. All surgeries were performed by one of five board-certified spine surgeons. Operative time was analyzed for stability using X-bar charts. Neurological outcomes were assessed using the modified McCormick Scale (mMS), and regression analysis was performed to evaluate the relationship between operative time and mMS.</p><p><strong>Results: </strong>The study included 144 patients (82 men, 62 women; average age 50.3 ± 14.6 years). Tumors were located at cervical (67.4%) or thoracic (32.6%) levels, averaging 3.0 ± 1.2 vertebrae. The surgeon who performed 71 cases was defined as the experienced surgeon, and the other surgeons performed 10-24 cases, respectively. The mean operative time was 380.6 ± 140.7 min, and 135 cases achieved gross total resection. The average follow-up duration was 6.9 ± 3.9 years. X-bar charts showed surgical stability once the average number of cases exceeded 17. No significant correlation was found between operative time and mMS for any surgeon. Perioperative complications were minimal.</p><p><strong>Conclusions: </strong>X-bar charts are a valuable tool for objectively evaluating surgical stability. In intramedullary ependymoma surgeries, consistency in operative time was achieved after 17 cases, and longer procedures did not adversely affect neurological outcomes. This method could be extended to monitor procedural reliability in other complex surgical interventions.</p>","PeriodicalId":21976,"journal":{"name":"Spinal cord","volume":" ","pages":""},"PeriodicalIF":2.1000,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Spinal cord","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1038/s41393-025-01090-0","RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"CLINICAL NEUROLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Study design: Retrospective cohort study.
Objectives: To evaluate surgical consistency and clinical outcomes in intramedullary ependymoma (WHO grade II) cases by using X-bar charts as a tool to assess procedural stability.
Setting: The single institution in Japan.
Methods: This study included patients who underwent resection of intramedullary ependymomas between 2001 and 2023. All surgeries were performed by one of five board-certified spine surgeons. Operative time was analyzed for stability using X-bar charts. Neurological outcomes were assessed using the modified McCormick Scale (mMS), and regression analysis was performed to evaluate the relationship between operative time and mMS.
Results: The study included 144 patients (82 men, 62 women; average age 50.3 ± 14.6 years). Tumors were located at cervical (67.4%) or thoracic (32.6%) levels, averaging 3.0 ± 1.2 vertebrae. The surgeon who performed 71 cases was defined as the experienced surgeon, and the other surgeons performed 10-24 cases, respectively. The mean operative time was 380.6 ± 140.7 min, and 135 cases achieved gross total resection. The average follow-up duration was 6.9 ± 3.9 years. X-bar charts showed surgical stability once the average number of cases exceeded 17. No significant correlation was found between operative time and mMS for any surgeon. Perioperative complications were minimal.
Conclusions: X-bar charts are a valuable tool for objectively evaluating surgical stability. In intramedullary ependymoma surgeries, consistency in operative time was achieved after 17 cases, and longer procedures did not adversely affect neurological outcomes. This method could be extended to monitor procedural reliability in other complex surgical interventions.
期刊介绍:
Spinal Cord is a specialised, international journal that has been publishing spinal cord related manuscripts since 1963. It appears monthly, online and in print, and accepts contributions on spinal cord anatomy, physiology, management of injury and disease, and the quality of life and life circumstances of people with a spinal cord injury. Spinal Cord is multi-disciplinary and publishes contributions across the entire spectrum of research ranging from basic science to applied clinical research. It focuses on high quality original research, systematic reviews and narrative reviews.
Spinal Cord''s sister journal Spinal Cord Series and Cases: Clinical Management in Spinal Cord Disorders publishes high quality case reports, small case series, pilot and retrospective studies perspectives, Pulse survey articles, Point-couterpoint articles, correspondences and book reviews. It specialises in material that addresses all aspects of life for persons with spinal cord injuries or disorders. For more information, please see the aims and scope of Spinal Cord Series and Cases.