Department of Orthopedic Surgery, Asan Medical Center, University of Ulsan College of Medicine, 388-1, PungNap-2-dong, SongPa-gu, Seoul, South Korea.
Department of Orthopedic Surgery, Asan Medical Center, University of Ulsan College of Medicine, 388-1, PungNap-2-dong, SongPa-gu, Seoul, South Korea.
Spine J. 2018 Jul;18(7):1116-1121. doi: 10.1016/j.spinee.2017.10.069. Epub 2017 Nov 7.
Research shows the progression of ossification of the posterior longitudinal ligament (OPLL) following decompressive surgery for cervical myelopathy, particularly in cases presenting with continuous or mixed radiographic types. To date, no study has investigated OPLL progression within each motion segment.
To evaluate progression of cervical OPLL in each motion segment using a novel system of classification, and to identify risk factors for OPLL progression following laminoplasty.
STUDY DESIGN/SETTING: Retrospective case series.
This study included 34 patients (86 segments) with cervical myelopathy secondary to OPLL.
Clinical and radiological data (plain radiographs and computed tomography [CT]) were obtained.
Clinical data from 34 patients (86 segments) with cervical myelopathy secondary to OPLL were evaluated retrospectively. All subjects had undergone laminoplasty at a single center. Sagittal reconstructive CT images were used to measure OPLL thickness in each segment. Ossified masses were classified into four types according to the degree of disc space involvement: type 1 (no involvement); type 2 (involving disc space but not crossing); type 3 (crossing disc space but not fused); and type 4 (complete bridging). Range of motion (ROM) for each segment was measured using dynamic radiographs. Statistical analyses were performed to determine the degree of OPLL progression according to the four disc space involvement types and ROM.
Mean OPLL progression was significantly higher in types 2 (1.3 mm) and 3 (1.5 mm) than in type 1 (0.5 mm) (p<.001). Severe progression (change in thickness >2 mm) was more frequent in types 2 (8 of 29) and 3 (7 of 16) than in types 1 (1 of 35) or 4 (0 of 6) (p=.002). In types 2 or 3, ROM>5° was correlated with severe OPLL progression (52% vs. 8%; p=.035).
Type 2 or 3 disc involvement and segmental ROM>5° were risk factors for OPLL progression. Classification of cervical OPLL according to disc involvement may help predict OPLL progression following laminoplasty. Close follow-up is warranted in cases of type 2 or 3 with greater segmental motion.
研究表明，颈椎后纵韧带骨化症（OPLL）在减压手术后会进展，特别是在连续或混合影像学类型的病例中。迄今为止，尚无研究在每个运动节段内探讨 OPLL 的进展。
使用新的分类系统评估每个运动节段颈椎 OPLL 的进展，并确定椎板成形术后 OPLL 进展的危险因素。
研究设计/设置：回顾性病例系列。
本研究纳入了 34 例（86 个节段）颈椎 OPLL 继发脊髓病患者。
获得临床和影像学数据（平片和计算机断层扫描[CT]）。
回顾性评估了 34 例（86 个节段）颈椎 OPLL 继发脊髓病患者的临床资料。所有患者均在单中心行椎板成形术。矢状位重建 CT 图像用于测量每个节段的 OPLL 厚度。根据椎间盘间隙受累程度将骨化块分为四型：1 型（无受累）；2 型（受累但不穿过椎间盘间隙）；3 型（穿过椎间盘间隙但未融合）；4 型（完全桥接）。使用动力位 X 线片测量每个节段的活动范围（ROM）。进行统计学分析以确定根据四种椎间盘间隙受累类型和 ROM 评估的 OPLL 进展程度。
2 型（1.3mm）和 3 型（1.5mm）的 OPLL 进展程度明显高于 1 型（0.5mm）（p<0.001）。2 型（29 个中的 8 个）和 3 型（16 个中的 7 个）中严重进展（厚度变化>2mm）的发生率高于 1 型（35 个中的 1 个）或 4 型（6 个中的 0 个）（p=0.002）。在 2 型或 3 型中，ROM>5°与严重 OPLL 进展相关（52%比 8%；p=0.035）。
2 型或 3 型椎间盘受累和节段 ROM>5°是 OPLL 进展的危险因素。根据椎间盘受累对颈椎 OPLL 进行分类可能有助于预测椎板成形术后 OPLL 的进展。对于 2 型或 3 型且节段活动度较大的患者，需要密切随访。
