BACKGROUND Osteotomies in the cervical spine are technically challenging. The purpose of this study was to evaluate the feasibility of the modified pedicle subtraction osteotomy (PSO) technique at C7 to be used for the treatment of cervicothoracic kyphosis secondary to ankylosing spondylitis. METHODS A total of 120 cervical spine computed tomography (CT) scans (of 82 male and 38 female patients) were evaluated. The scans were taken parallel to the middle sagittal plane and the sagittal plane intersecting the pedicles. Simulated osteotomy was performed by setting the apex of the wedge osteotomy at different points, and morphologic measurements were obtained. Seven patients with cervicothoracic kyphosis who underwent a modified PSO at C7 between May 2009 and June 2015 were retrospectively evaluated. The mean follow up was 32.9 months (range 21-54 months). Preoperative and postoperative chin-brow vertical angle (CBVA), sagittal vertical axis (SVA) and sagittal Cobb angle of the cervical region were reviewed. The outcomes were analyzed through various measures, which included the 36-Item Short Form Health Survey (SF-36) and a visual analog scale for neck pain. RESULTS In this morphometric study, a modified PSO was performed on 87 patients (59 male and 28 female) with a reasonable ratio of 72.5%. In the case series, radiographic parameters and health-related quality-of-life measures were found to show significant postoperative improvement in all patients. No major complications occurred, and no implant failures were noted until the latest follow up. CONCLUSIONS The modified PSO is a safe and valid alternative to the classic PSO, allowing for excellent correction of cervical kyphosis and improvement in health-related quality-of-life measures.

中文翻译：

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改良的C7椎弓根减法截骨术用于校正颈胸椎后凸畸形。

背景技术颈椎的截骨术在技术上具有挑战性。这项研究的目的是评估在C7改良的椎弓根减法截骨术（PSO）技术用于治疗强直性脊柱炎继发的颈胸椎后凸畸形的可行性。方法评估了120例颈椎CT扫描（82例男性和38例女性）。扫描平行于中间矢状面和与椎弓根相交的矢状面。通过在不同点设置楔形截骨的顶点进行模拟截骨，并获得形态学测量值。回顾性评估了2009年5月至2015年6月在C7接受改良PSO的7例颈胸椎后凸畸形患者。平均随访32次。9个月（范围21-54个月）。回顾了术前和术后下颌垂直角（CBVA），矢状垂直轴（SVA）和颈椎矢状Cobb角。通过各种措施对结局进行了分析，包括36项简短形式健康调查（SF-36）和颈部疼痛的视觉模拟量表。结果在该形态计量学研究中，对87例患者（男性59例，女性28例）进行了改良的PSO，合理比例为72.5％。在病例系列中，发现放射学参数和与健康相关的生活质量衡量指标显示所有患者术后均有明显改善。在最近的随访之前，没有发生重大并发症，也没有发现植入失败。结论修改后的PSO是经典PSO的安全有效替代方案，