Koda Masao, Furuya Takeo, Okawa Akihiko, Aramomi Masaaki, Inada Taigo, Kamiya Koshiro, Ota Mitsutoshi, Maki Satoshi, Ikeda Osamu, Takahashi Kazuhisa, Mannoji Chikato, Yamazaki Masashi
Department of Orthopaedic Surgery, Chiba University Graduate School of Medicine, 1-8-1, Inohana, Chuo-Ku, Chiba, 260-8670, Japan.
Department of Orthopaedic Surgery, Chiba Aoba Municipal Hospital, Chiba, Japan.
Eur Spine J. 2015 Nov;24(11):2555-9. doi: 10.1007/s00586-015-3888-z. Epub 2015 Mar 26.
The motion at the non-ossified segment of the ossification of the posterior longitudinal ligament (OPLL) is thought to be highly correlated to aggravation of symptoms of myelopathy. The rationale for posterior decompression with instrumented fusion (PDF) surgery is to limit the motion of the non-ossified segment of OPLL by stabilization. The purpose of the present study was to elucidate the course of bone union and remodelling of the non-ossified segment of thoracic OPLL (T-OPLL) after PDF surgery.
A total of 29 patients who underwent PDF surgery for T-OPLL were included in this study. We measured the thickness of the OPLLs by determining the thickest part of the OPLL in the sagittal multi-planer reconstruction CT images pre- and post-operatively. Five experienced spine surgeons independently performed CT measurements of OPLL thickness twice. Japanese Orthopaedic Association score for thoracic myelopathy was measured as clinical outcome measure.
Non-ossified segment of OPLLs fused in 24 out of 29 (82.8 %) patients. The average thickness of the OPLL at its thickest segment was 8.0 mm and decreased to 7.3 mm at final follow-up. The decrease in ossification thickness was significantly larger in the patients who showed fusion of non-ossified segments of OPLL compared with that in the patients did not show fusion. There was no significant correlation between the clinical outcome and the decrease in thickness of the OPLLs.
The results of this study showed that remodelling of the OPLLs, following fusion of non-ossified segment of OPLLs, resulted in a decreased OPLL thickness, with potential for a reduction of spinal cord compression.
后纵韧带骨化（OPLL）非骨化节段的活动被认为与脊髓病症状加重高度相关。后路减压并器械融合（PDF）手术的原理是通过稳定来限制OPLL非骨化节段的活动。本研究的目的是阐明PDF手术后胸段OPLL（T-OPLL）非骨化节段的骨愈合和重塑过程。
本研究纳入了29例行T-OPLL的PDF手术患者。我们通过术前和术后矢状多平面重建CT图像确定OPLL最厚部分来测量OPLL的厚度。五位经验丰富的脊柱外科医生独立对OPLL厚度进行了两次CT测量。将日本骨科协会胸段脊髓病评分作为临床结局指标进行测量。
29例患者中有24例（82.8%）OPLL的非骨化节段融合。OPLL最厚节段的平均厚度为8.0mm，末次随访时降至7.3mm。与未出现融合的患者相比，OPLL非骨化节段出现融合的患者其骨化厚度的减小更为显著。临床结局与OPLL厚度减小之间无显著相关性。
本研究结果表明，OPLL非骨化节段融合后，OPLL发生重塑，导致OPLL厚度减小，有可能减轻脊髓压迫。
