可动式椎间盘镜下椎体间融合术治疗腰椎滑脱症

Interbody fusion with mobile microendoscopic discectomy technique for lumbar spondylolisthesis

目的探讨可动式椎间盘镜（mobile microendoscopic discectomy, MMED）下椎体间融合术治疗腰椎滑脱症的疗效。方法2013年5月至2015年12月MMED下椎体间融合术治疗腰椎滑脱症62例，男34例，女28例；年龄34-67岁，平均56岁。均有腰痛及腿痛症状，腰痛重于腿痛，活动后加重。术前Oswestry功能障碍指数（Oswestry disability index，ODI）平均为38.9%±12.1%，腰痛疼痛视觉模拟评分（visual analogue scale，VAS）平均为（6.1±4.1）分。影像学检查示Ⅰ度滑脱50例，Ⅱ度滑脱12例。退行性滑脱40例，峡性滑脱22例。责任节段为L 4，5 42例、L 5S1 20例。退变性滑脱采用棘突旁入路，峡性滑脱采用经多裂肌与最长肌间隙的椎间孔入路，于症状严重侧取纵行切口长约2.5 cm，MMED下采用精细骨凿和磨钻去除关节突内侧扩大开窗，摘除椎间盘，充分刮除终板软骨。退行性滑脱者潜行咬除对侧黄韧带、松解对侧神经根；7例有双侧神经症状、狭窄及滑脱严重者在对侧行MMED下开窗减压。退出内套管，直视下试模撑开椎间隙，应用自体骨与异体骨混合植骨并置入cage。X线透视下经椎弓根穿刺，置入空心椎弓根螺钉，预设复位距离，经皮插入连接棒复位固定。记录手术时间、出血量，门诊随访评估疗效。结果2例定位错误者于术中矫正，无术中转为开放手术者，均未发生神经损伤。手术时间100-200 min，平均120 min；术中出血量（估计）为100-300 ml，平均150 ml。术后影像学检查示脊柱序列改善、减压充分，滑脱复位率（滑脱复位距离/术前滑脱距离）平均68%。56例随访12-24个月，其余6例随访6-9个月。末次随访时ODI降低至8.1%±6.9%，VAS下降至（1.5±1.2）分，均较术前明显改善。应用MacNab法评定疗效，优33例、良26例，可3例。结论MMED下椎体间融合术为腰椎滑脱症提供了一种微创治疗方法，能明显缓解症状并恢复脊柱序列，术后近期疗效良好。

Objective To investigate the feasibility and clinical effect of intervertebral body fusion with movable micro- endoscopic discectomy （MMED） in the treatment of lumbar spondylolisthesis. Methods From May 2013 to December 2015, 62 cases of lumbar spondylolisthesis were treated with MMED, including 34 males and 28 females, aged 34-67 years （mean 56 years）. All patients had symptoms of low back pain and leg pain, preoperative mean Oswestry disability index （ODI） was 38.9%±12.1%, visual analogue scale （VAS） low back pain 6.1±4.1; imaging examination showed 1 and 2 degree of spondylolisthesis in 50 and 12 cases, and degenerative and isthemic spondylolisthesis in 40 and 22 cases, respectively. The index levels included L4/5 in 42 patients and L5S1 in 20 patients. A 2.5 cm longitudinal incision was made on symptomatic side along puncture sites of pedicle, para-spinous process approach and transforamina approach through muscle space were used for degenerative or isthemic spondylo- listhesis, respectively. Enlarged fenestration was performed with removal of medial part of facet using fine chisel and high-speed burr with MMED. The endplate cartilage was curetted and disc space was prepared adequately. For degenerative spondylolisthesis, contralateral nerve root was decompressed and released by the same approach. For 7 patients with bilateral neurological symp- toms, severe stenosis and spondylolisthesis, contralateral fenestration was performed under MMED. After removal of the inner tube and enlarging the disc space, a proper size of fusion cage was tested under direct vision, followed by insertion of suitable cage with autologous and allograft bone graft. The distance of spondylolistheis was measured and the expected reduction distance was preset on screw extension rod, followed by reduction and fixation under X-ray guidance. The operative time and blood loss were recorded, and patients were followed-up to evaluate clinical results. Results Despite 2 cases had mistakenly pre-operational surgical/ocation and were corrected during operation, all the surgery was successful, with no nerve injury or conversion to open surgery. The mean operative time was 120 min （range, 100-200 rain）, with a mean blood loss of 150 ml （range, 100-300 ml）. Postoperative radiographs showed sufficient decompression and reduction of spondylolisthesis with improvement of spinal alignment, and the aver- age reduction rate of the spondylolisthesis （reductive distance of spondylofisthesis/preoperative spondylolisthesis） was 68%. 56 cases were followed up for 12-24 months, the other 6 cases were followed up for 6-9 months. At the last follow-up, ODI decreased to 8.1%±6.9% and VAS decreased to 1.5±1.2, which was significantly improved compared with that before operation. The clinical results were excellent in 33 cases, good in 26, and fair in 3 according to the MacNab scale. Conclusion Interbody fusion under MMED provides a minimally invasive treatment for lumbar spondylolisthesis, which can provide satisfactory clinical results and re- store of spine alighment.