Department of Orthopaedic Surgery, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan.
Department of Orthopedic Surgery, Shinshu University, Matsumoto, Nagano, Japan.
Spine (Phila Pa 1976). 2021 Aug 15;46(16):E878-E887. doi: 10.1097/BRS.0000000000003961.
Retrospective multicenter study.
This study aimed to investigate the incidence and risk factors of subjacent disc wedging (SDW) in adolescent idiopathic scoliosis (AIS) patients with Lenke type 5 curve.
SDW is frequently observed after surgery; however, data about its mechanism and relations with outcome are limited.
Data of 59 patients with AIS with Lenke type 5 curves who underwent posterior spinal fusion to L3 as the lowest instrumented vertebra (LIV) were retrospectively analyzed. The subjacent disc angle (SDA) was defined as the angle between L3 (LIV) and L4. SDW was defined as the absolute value of SDA of 10° or higher 2 years postoperatively. The incidence of SDW was investigated between nonselective and selective thoracolumbar/lumbar (TL/L) fusion group. In the selective group, patients with and without SDW were compared.
Among 59 patients, 11 had nonselective and 48 had selective fusion. No patients in the nonselective group showed SDW versus 13 patients in the selective group (27%) showed SDW. In the selective group, patients with SDW showed significantly greater main thoracic curve, apical vertebral translation of the main thoracic curve, upper instrumented vertebra tilt, LIV tilt, and SDA 2 years postoperatively, whereas no differences were found in the coronal balance or clinical outcome. Multivariate analysis revealed preoperative T curve and SDA as predictors of SDW occurrence. T curve greater than 30° and SDA greater than 0° were calculated as cutoff values based on the receiver operating characteristic curve.
SDW is sometimes seen in Lenke type 5 patients with AIS who underwent selective TL/L fusion. SDW seemed to occur as a compensation mechanism for progressing deformity of unfused segments (thoracic curve and residual lumbar curve) to maintain coronal alignment. Preoperative T curve > 30° and SDA > 0° (lower-end vertebra as L4) were determined as risk factors for SDW occurrence.Level of Evidence: 3.
回顾性多中心研究。
本研究旨在探讨 Lenke 5 型曲线青少年特发性脊柱侧凸（AIS）患者中下位椎间盘楔变（SDW）的发生率及危险因素。
SDW 术后常发生，但有关其发病机制及与结果的关系资料有限。
回顾性分析 59 例 Lenke 5 型曲线 AIS 患者，后路脊柱融合至 L3 为最低固定椎体（LIV）。下位椎间盘角（SDA）定义为 L3（LIV）和 L4 之间的角度。术后 2 年 SDA绝对值≥10°定义为 SDW。在非选择性和选择性胸腰段/腰椎段（TL/L）融合组之间，研究 SDW 的发生率。在选择性组中，比较有和无 SDW 的患者。
59 例患者中，11 例为非选择性融合，48 例为选择性融合。非选择性组无患者出现 SDW，而选择性组 13 例（27%）患者出现 SDW。在选择性组中，SDW 患者术后主胸弯、主胸弯顶椎位移、上固定椎倾斜、LIV 倾斜和 SDA 明显大于无 SDW 患者，而冠状平衡或临床结果无差异。多因素分析显示术前 T 弯和 SDA 是 SDW 发生的预测因素。根据受试者工作特征曲线，T 弯>30°和 SDA>0°计算为截断值。
Lenke 5 型 AIS 患者选择性 TL/L 融合后，SDW 有时可见。SDW 似乎是为了维持冠状位的对线，作为未融合节段（胸弯和残余腰弯）进展性畸形的代偿机制而发生。术前 T 弯>30°和 SDA>0°（下位椎为 L4）被确定为 SDW 发生的危险因素。
3 级。
