Long-Term Outcome of Dynesys Dynamic Stabilization for Lumbar Spinal Stenosis

Many clinical studies over the past decade have indicated positive outcomes for patients treated with Dynesys dynamic stabilization for lumbar degenerative disease. However, long-term outcomes of Dynesys for lumbar spinal stenosis are rarely reported. The aim of this study was to analyze the long-term clinical and radiologic outcomes for patients with lumbar spinal stenosis treated with Dynesys stabilization.Thirty-eight patients with lumbar spinal stenosis were treated with Dynesys stabilization from July 2008 to March 2010. The minimal duration of follow-up was 72 months. The patients were divided into stenosis and spondylolisthesis groups according to degenerative spondylolisthesis. Clinical outcomes were evaluated using the Oswestry Disability Index (ODI) and visual analog scale (VAS). Radiographic evaluations included range of motion (ROM) and the disc heights of stabilized segments and the upper adjacent segments. We also evaluated the occurrence of radiographic and symptomatic adjacent segment degeneration (ASD).There were 23 patients in stenosis group and 15 patients in spondylolisthesis group. The ODI scores were significantly improved at the final follow-up evaluation, as compared to the baseline values (16.1 ± 5.7 vs. 57. 2 ± 14.2, t = 61.41, P < 0.01). The VAS scores for back and leg pain were significantly improved from 4.82 ± 0.89 and 4.04 ± 0.82 preoperatively to 0.93 ± 0.61 and 0.54 ± 0.51 postoperatively (t = 6.59, P < 0.01, and t = 5.91, P < 0.01, respectively). There were no differences between the two groups with respect to VAS and ODI scores. The ROM of stabilized segments decreased significantly from 7.8° ± 2.4° to 4.5° ± 1.5° (t = 7.18, P < 0.05), while the upper adjacent segments increased significantly from 8.3° ± 2.4° to 10.4° ± 2.4° (t = 2.87, P = 0.01). The change in disc height of stabilized segments was not significant (11.9 ± 2.1 preoperatively vs. 12.5 ± 1.5 postoperatively, t = 1.43, P = 0.15), whereas the decrease in disc height of the upper adjacent segments was significant (12.5 ± 2.0 preoperatively vs. 11.0 ± 1.7 postoperatively, t = 2.94, P = 0.01). The occurrence of radiographic and symptomatic ASD was 16% (6/38) and 3% (1/38), respectively.Decompression and Dynesys stabilization for lumbar stenosis with or without spondylolisthesis showed good long-term clinical and radiographic results. Lumbar stenosis with or without Grade I spondylolisthesis, particularly in patients <60 years of age with mild-to-moderate lumbar disc degeneration, would be one of the main indications for the Dynesys system.Dynesys动态固定系统治疗腰椎管狭窄症的长期随访研究摘要背景: 在过去十几年中有大量研究显示，Dynesys动态固定系统治疗腰椎退变性疾病取得良好的短期疗效，但是关于Dynesys系统治疗腰椎管狭窄症的长期随访研究较少。本研究的目的即是评估Dynesys动态稳定系统治疗腰椎管狭窄症的长期临床和影像学疗效。 方法: 回顾分析2008年7月-2010年3月采用Dynesys 动态固定治疗的腰椎管狭窄症患者38例，最短随访时间为72个月。所有患者根据是否存在腰椎退变滑脱分为腰椎管狭窄组和滑脱组。临床评价指标包括Oswestry 功能障碍指数(Oswestry disability index，ODI)和疼痛视觉模拟量表(visual analogue scale，VAS) 评分。影像学评估指标包括手术节段和近侧邻近节段活动度（range of motion, ROM）和椎间高度，以及影像学和症状学邻近节段退变的发生情况。 结果: 腰椎管狭窄组共有23例患者，滑脱组有15例患者。与术前相比，在末次随访时患者ODI评分显著改善(16.1 ± 5.7 vs. 57. 2± 14.2，t = 61.41，P < 0.01)。患者腰部和腿部VAS评分分别由术前的4.82 ± 0.89分和4.04 ± 0.82降至末次随访时的0.93 ± 0.61 分和 0.54 ± 0.51分 (t = 6.59，P < 0.01和 t = 5.91，P < 0.01)。两组患者末次随访时VAS和DOI评分差异无统计学意义。所有患者手术节段ROM由术前平均(7.8±2.4)°保留至末次随访时的(4.5±1.5)° (t = 7.18，P < 0.05)，近侧邻近节段ROM由术前的(8.3±2.4)°增加至末次随访时的(10.4±2.4)° (t = 2.87，P = 0.01)。手术节段椎间高度末次随访和术前相比差异无统计学意义（术前11.9 ± 2.1 mm vs. 12.5 ± 1.5 mm，t = 1.43，P = 0.15），近侧邻近节段椎间高度在末次随访时较术前显著降低(术前12.5 ± 2.0 mm vs. 术后11.0 ± 1.7 mm，t = 2.94，P = 0.01)。影像学和症状学ASD发生情况分别为16%（6/38）和3%（1/38）。 结论: 减压结合Dynesys动态固定系统治疗腰椎管狭窄症伴/不伴滑脱能够获得良好的长期临床疗效。腰椎管狭窄症伴或不伴I度滑脱，年龄小于60岁，腰椎间盘轻到中度退变是Dynesys动态固定系统的主要适应证之一。.