Sarwahi Vishal, Sugarman Etan P, Wollowick Adam L, Amaral Terry D, Lo Yungtai, Thornhill Beverly
Department of Orthopaedic Surgery, Montefiore Medical Center, The Albert Einstein College of Medicine, 3400 Bainbridge Avenue, 6th Floor, Bronx, NY 10467. E-mail address for V. Sarwahi:
Department of Epidemiology and Population Health, The Albert Einstein College of Medicine, Jack and Pearl Resnick Campus, 1300 Morris Park Avenue, Block, Room 341, Bronx, NY 10461. E-mail address:
J Bone Joint Surg Am. 2014 Jun 4;96(11):e92. doi: 10.2106/JBJS.M.01058.
A thorough understanding of pedicle morphology is necessary for pedicle screw placement. Previous studies classifying pedicle morphology, to our knowledge, have neither discussed the range of abnormal morphology nor correlated patient or curve characteristics with abnormal morphology to identify at-risk pedicles.
With the use of computed tomography (CT) images, we analyzed a total of 6116 pedicles from ninety-five patients without spinal deformity (forty-two females and fifty-three males) and ninety-one patients with adolescent idiopathic scoliosis (AIS) (sixty-eight females and twenty-three males). Pedicle morphology was classified as: Type A, a cancellous channel of >4 mm; Type B, a cancellous channel of 2 to 4 mm; Type C, a cortical channel of ≥2 mm; or Type D, a cortical or cancellous channel of <2 mm. Types B, C, and D were defined as abnormal. Patient demographic data and pedicle distribution were assessed for prevalence and likelihood of abnormal pedicle morphology. Postoperative CT images from fifty-nine patients with AIS were used to assess screw placement.
There was a significantly higher rate of abnormal pedicles in patients with AIS (p = 0.001). More abnormal pedicles were located in the thoracic spine compared with the lumbar spine both in patients without deformity (13.3% versus 2.0%) and patients with AIS (31.9% versus 2.4%). Significantly more abnormal pedicles were located on the concavity (p < 0.001), within the periapical region (p = 0.02), and on the apex of the curve (p = 0.03). Three times as many pedicle screws were misplaced in abnormal pedicles compared with normal pedicles (21% versus 7%).
Our study found a significantly higher prevalence of abnormal pedicles in the patients with AIS. Of the abnormal pedicles in these patients, most were in the thoracic spine, on the concave side, and in the periapical and apical regions.
Knowledge of abnormal pedicles may enable surgeons to anticipate and plan for difficult screw placement and further decrease risk to the patient.
全面了解椎弓根形态对于椎弓根螺钉置入至关重要。据我们所知，以往对椎弓根形态进行分类的研究，既未讨论异常形态的范围，也未将患者或侧弯特征与异常形态相关联以识别有风险的椎弓根。
利用计算机断层扫描（CT）图像，我们分析了95例无脊柱畸形患者（42例女性和53例男性）以及91例青少年特发性脊柱侧弯（AIS）患者（68例女性和23例男性）的总共6116个椎弓根。椎弓根形态分为：A型，松质骨通道>4mm；B型，松质骨通道2至4mm；C型，皮质骨通道≥2mm；或D型，皮质骨或松质骨通道<2mm。B、C和D型被定义为异常。评估患者人口统计学数据和椎弓根分布，以了解异常椎弓根形态的患病率和可能性。使用59例AIS患者的术后CT图像评估螺钉置入情况。
AIS患者中异常椎弓根的发生率显著更高（p = 0.001）。在无畸形患者（13.3%对2.0%）和AIS患者（31.9%对2.4%）中，与腰椎相比，胸椎中异常椎弓根更多。显著更多的异常椎弓根位于凹侧（p < 0.001）、根尖区域内（p = 0.02）以及侧弯顶点（p = 0.03）。与正常椎弓根相比，异常椎弓根中椎弓根螺钉误置的数量是正常椎弓根的三倍（21%对7%）。
我们的研究发现AIS患者中异常椎弓根的患病率显著更高。在这些患者的异常椎弓根中，大多数位于胸椎、凹侧以及根尖和顶点区域。
了解异常椎弓根可能使外科医生能够预测并规划困难的螺钉置入，并进一步降低对患者的风险。
