Sarwahi Vishal, Suggs William, Wollowick Adam L, Kulkarni Preethi M, Lo Yungtai, Amaral Terry D, Thornhill Beverly
*The Department of Orthopaedic Surgery †Division of Vascular Surgery ‡Department of Epidemiology & Population Health §Department of Radiology, Children's Hospital at Montefiore, Albert Einstein College of Medicine, Bronx, NY.
J Spinal Disord Tech. 2014 Apr;27(2):64-9. doi: 10.1097/BSD.0b013e31825bfecd.
A retrospective study.
To determine the incidence of pedicle screws close to vital structures and to identify patient or curve characteristics that increase the risk of screw misplacement.
Most pedicle screw misplacements are asymptomatic, thus they are frequently undetected. This study identifies the rate of screw placement in proximity to vital structures using postoperative computed tomography scans.
A total of 2132 screws in 101 patients, who underwent posterior spinal fusion for spinal deformity, were reviewed. Screws adjacent to great vessels and viscera were identified and evaluated. Patients with screws at risk (group B) were compared with patients without screws at risk (group A). Patient and curve characteristics were analyzed to determine whether a correlation with screw misplacement exists.
A total of 40 at risk screws (∼2%) were identified in 25 patients (∼25%). These 40 screws were in proximity to the aorta (31), left subclavian artery (1), esophagus (3), trachea (3), pleura (1), and diaphragm (1). Of the 31 screws close to the aorta, 10 screws in 6 patients were impinging or distorting the aortic wall. One hundred percent of misplaced screws were in the thoracic spine, 50% were misplaced laterally, 50% were 35 mm long, 57.5% were in pedicles with normal morphology, and 75% were in curves between 40 and 70 degrees. Median screw misplacement rate was 10% in group A and 13% in group B. Adjusted for age and preoperative Cobb angle, patients with a higher misplacement rate were more likely to have screws adjacent to vital organs [adjusted odds ratio: 1.06 (95% confidence interval, 1.01-1.13), P=0.033].
Although only a small number of screws were at risk, they occurred in a large percentage of patients (25%). A single at-risk screw causes a significant complication for the patient. Postoperative imaging beyond routine x-rays may be needed to detect at-risk screws in asymptomatic patients.
一项回顾性研究。
确定靠近重要结构的椎弓根螺钉的发生率，并识别增加螺钉误置风险的患者或脊柱侧弯特征。
大多数椎弓根螺钉误置是无症状的，因此常常未被发现。本研究使用术后计算机断层扫描来确定螺钉置于靠近重要结构处的发生率。
对101例行后路脊柱融合术治疗脊柱畸形的患者中总共2132枚螺钉进行了回顾。识别并评估靠近大血管和内脏的螺钉。将有螺钉置于危险位置的患者（B组）与无螺钉置于危险位置的患者（A组）进行比较。分析患者和脊柱侧弯特征，以确定是否与螺钉误置存在相关性。
在25例患者（约25%）中总共识别出40枚有危险的螺钉（约2%）。这40枚螺钉靠近主动脉（31枚）、左锁骨下动脉（1枚）、食管（3枚）、气管（3枚）、胸膜（1枚）和膈肌（1枚）。在靠近主动脉的31枚螺钉中，6例患者的10枚螺钉压迫或扭曲了主动脉壁。100%的误置螺钉位于胸椎，50%向外侧误置，50%长度为35毫米，57.5%位于形态正常的椎弓根，75%位于40至70度的脊柱侧弯中。A组螺钉误置率中位数为10%，B组为13%。校正年龄和术前Cobb角后，误置率较高的患者更有可能有靠近重要器官的螺钉[校正比值比：1.06（95%置信区间，1.01 - 1.13），P = 0.033]。
虽然只有少数螺钉有危险，但它们出现在很大比例的患者中（25%）。一枚有危险的螺钉会给患者带来严重并发症。对于无症状患者，可能需要进行常规X线以外的术后影像学检查以检测有危险的螺钉。
