Department of Orthopaedic Surgery, Shinshu University School of Medicine, Matsumoto-city, Nagano, Japan.
Spine (Phila Pa 1976). 2017 Dec 15;42(24):1895-1900. doi: 10.1097/BRS.0000000000002305.
A retrospective chart review.
The aim of this study was to investigate the incidence and characteristics of screw loosening in surgically treated adolescent idiopathic scoliosis (AIS) patients.
Pedicle screws are widely used in posterior spinal fusion for AIS, although postoperative loosening can occur. However, few reports exist on screw loosening after pedicle screw fixation in young scoliosis patients and the etiology of loosening is not well known.
One hundred twenty AIS patients (9 males, 111 females; mean age: 15.0 years) who had received pedicle screw fixation were retrospectively reviewed. All patients underwent routine computed tomography (CT) reconstruction scans at 6 months postoperatively to assess screw position, bony fusion, and the presence of screw loosening. The perforation status of each pedicle screw was assigned a grade of 0 to 3 using Rao classification.
Forty-three of 1624 (2.6%) screws showed evidence of loosening on CT. Screw loosening rates according to vertebral insertion level were upper instrumented vertebra (UIV): 9.6%; lower instrumented vertebra (LIV): 5.4%; one vertebra below the UIV: 1.8%; one vertebra above the LIV: 0.5%; two vertebrae below the UIV: 1.2%; and three vertebrae below the UIV: 0.9%. Screw loosening rates based on screw perforation grade were Grade 0: 1.4%; Grade 1: 3.1%; Grade 2: 15.5%; and Grade 3: 15.2%. Multivariate analysis revealed a distance from the UIV or LIV of one vertebra as well as the presence of major perforation to be independent factors affecting screw loosening. The odds ratios (ORs) of UIV/LIV insertion and major perforation were 73.4 and 17.2, respectively. When major perforations occurred in the UIV or LIV, the OR for loosening approached 1262.
Pedicle screw loosening after posterior spinal fusion in AIS patients tend to occur in the UIV or LIV. Major screw perforation is also significantly associated with screw loosening. The risk of loosening becomes compounded when major perforations are present in the UIV or LIV.
回顾性图表分析。
本研究旨在调查手术治疗青少年特发性脊柱侧凸（AIS）患者中螺钉松动的发生率和特征。
尽管术后可能会发生螺钉松动，但椎弓根螺钉广泛用于 AIS 的后路脊柱融合术。然而，关于年轻脊柱侧凸患者椎弓根螺钉固定后的螺钉松动以及松动的病因知之甚少。
回顾性分析 120 例接受椎弓根螺钉固定的 AIS 患者（男 9 例，女 111 例；平均年龄：15.0 岁）。所有患者均在术后 6 个月行常规计算机断层扫描（CT）重建扫描，以评估螺钉位置、骨融合和螺钉松动情况。采用 Rao 分类法将每个椎弓根螺钉的穿透状态分为 0-3 级。
在 1624 个螺钉中，有 43 个（2.6%）在 CT 上显示有松动的证据。根据椎弓根螺钉插入水平，螺钉松动率为：上固定椎（UIV）：9.6%；下固定椎（LIV）：5.4%；UIV 下方一个椎体：1.8%；LIV 上方一个椎体：0.5%；UIV 下方两个椎体：1.2%；UIV 下方三个椎体：0.9%。根据螺钉穿透等级，螺钉松动率为：Grade 0：1.4%；Grade 1：3.1%；Grade 2：15.5%；Grade 3：15.2%。多变量分析显示，UIV 或 LIV 上方或下方一个椎体的距离以及大穿孔是影响螺钉松动的独立因素。UIV/LIV 插入和大穿孔的优势比（OR）分别为 73.4 和 17.2。当 UIV 或 LIV 发生大穿孔时，松动的 OR 接近 1262。
AIS 患者后路脊柱融合术后椎弓根螺钉松动倾向于发生在 UIV 或 LIV。大穿孔也与螺钉松动显著相关。当 UIV 或 LIV 存在大穿孔时，松动的风险会增加。
4 级。
