Radiological and clinical outcome of screw placement in adolescent idiopathic scoliosis: evaluation with low-dose computed tomography

European Spine Journal

Pavel Maly¹  Acke Ohlin¹  Pia C. Sundgren¹  Kasim Abul-Kasim¹  Anita Strömbeck¹ 

[1] Faculty of Medicine, University of Lund, Lund, Sweden

关键词: Low-dose CT;    Neurovascular complications;    Medial cortical perforation;    Lateral cortical perforation;    Anterior cortical perforation;   

DOI  :  10.1007/s00586-009-1203-6

学科分类：骨科学

来源: Springer

【 摘 要 】

Posterior corrective surgery using “all pedicle screw construct” carries risk of neurovascular complications. The study aims were to assess the screw placement in patients with adolescent idiopathic scoliosis using CT with low-radiation dose, and to evaluate the clinical outcome in patients with misplaced pedicle screws. CTs of 49 consecutive patients (873 screws, 79% thoracic) were retrospectively evaluated by two independent radiologists. A new grading system was developed to distinguish between lateral, medial and anterior cortical perforations, endplate perforation and foraminal perforation. The grading system is based on whether the cortical violation is partial or total rather than on mm-basis. The overall rate of screw misplacement was 17% (n = 149): 8% were laterally placed and 6.1% were medially placed. The rates of anterior cortical, endplate and foraminal perforation were 1.5, 0.9, and 0.5%, respectively. Lateral cortical perforation was more frequent in the thoracic spine (P = 0.005), whereas other types of misplacement including medial cortical perforation were more frequent on the left and the concave side of scoliotic curves (P = 0.002 and 0.003). No neurovascular complications were reported. The association between the occurrence of screw misplacement and the Cobb angle was statistically significant (P = 0.037). Misplacements exceeding half screw diameter should be classified as unacceptable. Low-dose CT implies exposing these young individuals to a significantly lower radiation dose than do other protocols used in daily clinical practice. We recommend using low-dose CT and the grading system proposed here in the postoperative assessment of screw placement.

【 授权许可】

Unknown