Department of Orthopaedics and Traumatology, Kocaeli University School of Medicine, Kocaeli, Turkey.
Spine (Phila Pa 1976). 2011 Sep 1;36(19):1592-9. doi: 10.1097/BRS.0b013e3181f54f7f.
Retrospective study.
Investigate the radiographic features of the subtypes of Lenke 1A curves to help to determine the optimum distal fusion level selection.
The Lenke 1A was the most frequently evaluated curve type in adolescent idiopathic curves. Miyanji et al suggested that the lumbar modifier type A does not accurately define the behavior of the compensatory lumbar curve in Lenke 1A. The tilt of L3 and L4 in the coronal plane may have a significant role in determining distal fusion level.
Thirty-six patients with Lenke type 1A idiopathic scoliosis treated by segmental posterior instrumentation with an average of 52.1-month follow-up were retrospectively analyzed. Four different curve types depending on L3-L4 vertebral tilt were described. The radiographic measurements including proximal and distal junctional kyphosis was obtained at latest follow-up. RESULTS.: Preoperative mean major curve Cobb angle of 47.6° was corrected to 12.9° showing a correction rate of 72.8% and maintained at 14.2°. Loss of correction at final follow-up was 2.7%. The mean compensatory curve Cobb angle of 24.4° was corrected to 8.2°. All patients balanced after surgery although seven had more than -5° clavicle angle before surgery. The mean preoperative and postoperative sagittal T5-T12 angles were 30.6° and 26.2°, respectively, and 29.1° at latest follow-up. The mean preoperative, postoperative, and latest follow-up T10-L2 sagittal Cobb angles were -0.2°, 2.0°, and 4.2°. Three patients diagnosed as distal junctional kyphosis at latest follow-up.
Distal fusion level should be extended to at least lower end vertebra (LEV) -1 in type 1A-A and type 1A-D curves, while it might be necessary to go down to LEV in the type 1A-B and 1A-C. It seems that LEV might be a reliable guide to select ideal distal fusion level in Lenke type 1A curves.
回顾性研究。
探讨 Lenke 1A 型曲线亚型的影像学特征，以帮助确定最佳的远端融合水平选择。
Lenke 1A 是青少年特发性脊柱侧弯中最常评估的曲线类型。Miyanji 等人认为，腰椎修正 A 型并不能准确定义 Lenke 1A 中代偿性腰椎曲线的行为。L3 和 L4 在冠状面上的倾斜可能在确定远端融合水平方面发挥重要作用。
回顾性分析了 36 例采用节段性后路器械治疗的 Lenke 1A 型特发性脊柱侧弯患者，平均随访 52.1 个月。根据 L3-L4 椎体倾斜，描述了四种不同的曲线类型。在末次随访时，获得了包括近端和远端交界后凸角的影像学测量值。
术前平均主弯 Cobb 角为 47.6°，矫正至 12.9°，矫正率为 72.8%，并维持在 14.2°。末次随访时丢失矫正 2.7%。平均代偿性曲线 Cobb 角为 24.4°，矫正至 8.2°。所有患者术后均平衡，尽管术前有 7 例锁骨角大于-5°。术前和术后平均矢状面 T5-T12 角分别为 30.6°和 26.2°，末次随访时为 29.1°。术前、术后和末次随访时 T10-L2 矢状 Cobb 角平均分别为-0.2°、2.0°和 4.2°。3 例患者在末次随访时诊断为远端交界后凸。
在 1A-A 型和 1A-D 型曲线中，远端融合水平应至少延伸至下终椎（LEV）-1，而在 1A-B 和 1A-C 型中，可能需要降至 LEV。似乎 LEV 可能是选择 Lenke 1A 型曲线理想远端融合水平的可靠指南。
