“揭盖式”胸椎管后壁切除术治疗单节段胸椎黄韧带骨化症的疗效及其影响因素

Surgical outcome and associated factors of "cap uncovering" en-bloc removal of the spinal canal′s posterior wall surgery for single-level thoracic ossification of ligamentum flavum

中文关键词:  胸椎黄韧带骨化症  手术疗效  影响因素

英文关键词:Thoracic ossification of ligament flavum  Surgical outcome  Associated factors

中文摘要:

  【摘要】 目的：探讨“揭盖式”胸椎管后壁切除术治疗单节段胸椎黄韧带骨化症（OLF）的疗效，并分析其影响因素。方法：回顾性分析2005年2月~2013年5月因确诊单节段胸椎OLF于我院接受“揭盖式”胸椎管后壁切除术并获得随访的44例患者，排除合并其他脊柱疾病、超过1个节段分布以及外伤致病者。其中男23例，女21例；手术时年龄24~76岁，平均56.8岁。节段分布: T10/11 20例，T11/12 14例，T9/10 4例，T8/9 2例，T2/3 2例，T4/5 1例，T1/2 1例。术前JOA脊髓功能评分（11分法）为2~9分，平均6.68±1.76分。末次随访时按JOA评分改善率进行疗效分级，并计算疗效优良率。按术前MRI横断面上骨化黄韧带对脊髓的压迫程度分度，观察T2WI脊髓内有无高信号及矢状位骨化形态。利用术前CT测量并计算横断面椎管中央、侧界及二者中点部位（旁正中）的椎管前后径残余率，矢状位椎管前后径残余率，椎管面积残余率，观察Sato′s 分型及骨化生长位置。采用单因素线性相关分析检验年龄、性别、术前病程、术前JOA评分、单侧/双侧骨化、硬膜骨化、脑脊液漏、骨化生长位置、手术节段、T2WI脊髓内高信号、MRI矢状位骨化形态、Sato′s分型以及各椎管侵占测量参数与JOA评分改善率的相关性，对有统计学意义的影响因素与JOA评分改善率采用多元线性回归分析进行检验。结果：随访10~99个月，平均40个月。末次随访时，JOA评分为5~11分，平均8.84±1.83分；改善率为-20%~100%，平均58.17%；疗效判定：优13例，良20例，一般9例，差2例，优良率为75.0%（33/44）。单因素相关分析显示，术前JOA评分、单侧/双侧骨化、硬膜骨化、骨化生长位置、T2WI脊髓内高信号、Sato′s分型、MRI脊髓受压分度及CT横断面椎管前后径残余率（椎管侧界和旁正中）、矢状位椎管前后径残余率、椎管面积残余率与JOA评分改善率有相关性（P＜0.05），年龄、性别、术前病程、脑脊液漏、OLF手术节段、MRI骨化形态、CT横断面椎管前后径残余率（中央）与JOA评分改善率无相关性（P＞0.05）。多元回归分析显示，术前JOA评分与CT横断面椎管前后径残余率（旁正中）对手术疗效的影响有统计学意义（P＜0.05），而单侧/双侧骨化、硬膜骨化、骨化生长位置、T2WI脊髓内高信号、Sato′s分型、MRI脊髓受压分度、CT横断面椎管前后径残余率（侧界）、矢状位椎管前后径残余率及椎管面积残余率对手术疗效的影响无统计学意义（P＞0.05）。结论：“揭盖式”胸椎管后壁切除术治疗单节段胸椎OLF疗效相对较好，CT横断面椎管前后径残余率（旁正中）与术前JOA评分是影响手术疗效的重要因素。

英文摘要:

  【Abstract】 Objectives: To assess the efficacy of "cap uncovering" en-bloc removal of the spinal canal′s posterior wall and the prognostic associated factors for thoracic myelopathy caused by single-level thoracic ossification of ligamentum flavum(OLF). Methods: Patients with thoracic myelopathy induced by OLF underwent en-bloc removal of the spinal canal′s posterior wall termed as the "cap uncovering" technique between February 2005 and May 2013 and were retrospectively reviewed. Exclusion criteria were as follows: other tandem spinal diseases, OLF of more than one segment, cases caused by injury. A total of 44 cases was included. Among these 44 cases, there were 23 males and 21 females with a mean age of 56.8 years(range 24-76 years). Segmental distributions was as follows: 20 cases of T10/11, 14 cases of T11/12, 4 cases of T9/10, 2 cases of T8/9, 2 cases of T2/3, 1 case of T4/5, 1 case of T1/2. The modified JOA score and the recovery rate were used to measure the outcomes. The mean JOA score was 6.68±1.76 preoperatively. The follow-up results were classified according to the recovery rate and then the rate of excellent or good was calculated. The degree of spinal canal occupation was graded on axial T2 weighted MRI. The type of OLF and intramedullary high signal intensity on T2-weighted MRI was also evaluated. The spinal canal diameters were measured at the maximally stenosed level on axial and sagittal CT. The spinal canal diameter on axial CT was measured at three sites: the midline of the canal, the boundary of the canal, and the paramedian point. The canal diameter occupied ratio and the cross-section area occupied ratio were calculated. Sato′s classification and the growth position of OLF were observed on CT. Correlations between the surgical outcomes and various factors[age, gender, preoprative JOA scores, preoprative duration, unilateral/bilateral ossification, leakage of cerebrospinal fluid(CSF), the growth position, operative segment, high intensity signal in the spinal cord, shape on the sgittal MRI, dural ossification, Sato′s classification, degree of spinal canal occupation on axial MRI, canal diameter occupied ratio on sagittal and axial CT, the cross-section area occupied ratio] were analyzed through univariate linear correlation analysis, and multiple linear regression analysis was then used. Results: The mean follow-up period of these 44 cases was 40 months(range, 10-99 months). At final follow-up, the JOA score increased to 5-11(mean 8.84±1.83), and the JOA recovery rate was -20%-100%(mean 58.17%). Surgical outcomes were as follows: 13 excellent, 20 good, 9 fair and 2 poor. The rate of excellent or good was 75.0%(33/44). The univariate linear correlation analysis showed that preoprative JOA scores, unilateral/bilateral ossification, dural ossification, the growth position, high intensity signal in the spinal cord, Sato′s classification and degree of spinal canal occupation on axial MRI, canal diameter occupied ratio on sagittal CT, canal diameter occupied ratio on axial CT(boundary), canal diameter occupied ratio on axial CT(paramedian), the cross-section area occupied ratio might be correlated to JOA recovery rate(P＜0.05). Age, gender, preoprative duration, leakage of CSF, operative segment, shape on the sgittal MRI, canal diameter occupied ratio on axial CT(midline) were not associated with JOA recovery rate(P＞0.05). The multiple linear regression analysis revealed that only canal diameter occupied ratio(paramedian) on axial CT and preoprative JOA scores significantly correlated with recovery rate(P＜0.05). Unilateral/bilateral ossification, dural ossification, the growth position, high intensity signal in the spinal cord, degree of spinal canal occupation on axial MRI, Sato′s classification and other occupied index had no significant effect on surgical outcome(P＞0.05). Conclusions: "Cap uncovering" en-bloc removal of the spinal canal′s posterior wall surgery is effective for single-level thoracic OLF. Canal diameter occupied ratio(paramedian) on axial CT and preoperative JOA scores have significant effect on surgical outcome.