PEDICLE MORPHOLOGY IN SCOLIOSIS: CLASSIFICATION AGREEMENT FOR PRE-OPERATIVE EVALUATION

ABSTRACT Objectives Although Watanabe morphological classification is well known, there is no consensus of its use among spine surgeons. We propose an analysis of the Watanabe classification by three observers, one senior and two recently graduated orthopedic spine surgeons, and its applicability in pre-operative evaluation. Methods An intraobserver and interobserver analysis of the classifications of 937 thoracic pedicles among 55 scoliosis patients treated surgically in two institutions. The average age at time of surgery was 16.3 years (10- 50 years). The etiologies of the scoliosis were: idiopathic (n= 47), congenital (n=4), syndromic (n= 3) and neuromuscular (n=1). The mean Cobb angle was 67 degrees (41- 120º). The evaluation of the thoracic pedicle was performed using pre-operative CT images. Results A total of 937 pedicles were classified by three observers with percentages of 47.5% type A, 28.6% type B, 17.1% type C and 6.9% type D for the total pedicles, convex and concave. Intraobserver agreement was fair to almost perfect (kappa 0.34 to 0.92) and interobserver agreement was fair to moderate (kappa 0.33 to 0.59) with statistical significance of p<0.001. Conclusion Watanabe classification remains a good method for predicting intraoperative difficulties, and has better agreement as the surgeon becomes more experienced. Level of evidence II; Prognostic Studies.

摘要
目的 尽管渡边形态分类法（Watanabe morphological classification）已被广泛认知，但脊柱外科医师对其临床应用尚未达成统一共识。本研究由3名观察者（1名高年资脊柱外科医师与2名刚毕业的脊柱矫形外科医师）对该分类法开展分析，并探讨其在术前评估中的适用性。
方法 对两家医疗机构收治的55例接受手术治疗的脊柱侧凸患者的937个胸椎椎弓根进行观察者内及观察者间一致性分析。患者手术时的平均年龄为16.3岁（年龄范围10~50岁）。脊柱侧凸的病因分类为：特发性（n=47）、先天性（n=4）、综合征性（n=3）及神经肌肉性（n=1）。患者的平均Cobb角（Cobb angle）为67°（范围41~120°）。所有胸椎椎弓根的评估均采用术前CT影像完成。
结果 3名观察者共完成937个椎弓根的分类，所有凸侧与凹侧椎弓根整体占比为：A型47.5%、B型28.6%、C型17.1%、D型6.9%。观察者内一致性为一般至近乎完美（kappa值0.34~0.92），观察者间一致性为一般至中等（kappa值0.33~0.59），且两组一致性均具有显著统计学意义（p<0.001）。
结论 渡边形态分类法仍是预测术中操作难度的有效工具，且脊柱外科医师的临床经验越丰富，分类一致性越好。
证据等级：Ⅱ级；预后研究类。