后路复位技术在重度腰椎滑脱症治疗中的应用

APPLICATION OF REDUCTION BY POSTERIOR APPROACH TO TREAT SEVERE SPONDYLOLISTHESIS

目的总结分析经后路复位治疗重度腰椎滑脱症的复位技巧,并探讨神经牵张损伤预防方法。方法回顾性分析2007年7月-2011年4月收治且随访资料完整的17例重度腰椎滑脱症患者临床资料。其中男2例,女15例;年龄8～67岁,中位年龄15岁。病程5个月～16年4个月,中位病程18个月。重度腰椎滑脱部位:L4 1例,L5 16例。滑脱Meyerding分度为Ⅲ度12例,Ⅳ度5例。16例为发育性滑脱,其中高度发育不良型9例,低度发育不良型7例;1例为L5创伤性滑脱。16例L5椎体滑脱根据腰骶椎滑脱国际脊柱畸形学会(SDSG)标准分型,4型6例,5型9例,6型1例。患者均行后路椎管减压、双向Schanz钉固定并复位滑脱椎体、椎间及后外侧联合植骨融合,以及纠正腰骶部畸形。根据出行神经根张力调整复位幅度,原则上复位要纠正至MeyerdingⅡ度以内。手术前后摄站立位全脊柱正侧位X线片(包括双侧股骨头)分析手术前后椎体滑脱幅度和腰骶角纠正情况;疼痛视觉模拟评分(VAS)评估术后神经根减压情况;CT三维重建评价植骨融合情况。结果术后除1例出现L5神经根麻痹症状,4周后自行缓解外,其余患者均无神经损害加重。术后切口均Ⅰ期愈合。17例均获随访,随访时间12～48个月,平均25个月。椎体滑移百分比、腰骶角、下肢疼痛VAS评分分别由术前的72%±10%、(18.2±3.5)°、(7.0±1.5)分改善至术后12个月的12%±6%、(—7.3±2.9)°、(1.5±1.3)分,差异均有统计学意义(P<0.05)。术后12个月CT三维重建均可见植骨区成熟骨桥生长,未发现断钉、断棒和复位丢失情况。结论采用后路椎管减压、双向Schanz钉固定复位滑脱椎体、椎间及后外侧联合植骨融合治疗重度腰椎滑脱临床结果满意。通过降低复位后椎间高度、术中根据神经根张力情况调整滑脱椎体复位幅度、纠正腰骶后凸畸形等措施,可预防神经根牵张损伤。

Objective To investigate the technique and to discuss the method to prevent nerve stretch injury. of reduction by posterior approach for severe spondylolisthesis, Methods Between July 2007 and April 2011, 17 patients with severe spondylolisthesis underwent reduction, fixation, and fusion by posterior approach. There were 2 males and 15 females with a median age of 15 years （range, 8-67 years） and a median disease duration of 18 months （range, 5 months-16 years and 4 months）. The level of spondylolisthesis was at L4 in 1 case and Ls in 16 cases; the spondylolisthesis was at degree III in 12 cases and degree IV in 5 cases according to Meyerding classification. There were 16 cases of developmental spondylolisthesis （high- dysplastic and low-dysplasia spondylolisthesis in 9 and 7 cases, respectively） and 1 case of traumatic spondylolisthesis; 16 cases of developmental spondylotisthesis at Ls level included 6 cases of type 4, 9 case of type 5, and 1 case of type 6 according to Spinal Deformity Study Group （SDSG） classification. All cases underwent posterior spinal decompression, Schanz screw fixation for the slipped vertebrae, the intervertebral and posterolateral fusion and reduction of the slipped vertebrae, and correction of the lumbosacral kyphosis. The reductive degree of slipped vertebrae was modulated according to the strain of exiting spinal root. The slip degree should be reduced within Meyerding degree II. The anteroposterior and lateral radiographs of whole spine were taken in a standardized standing position to observe the correction of displacement severity and lumbosacral angle. The nerve function and pain score of lower extremity were evaluated by neurological Frankel grade and visual analogue scale （VAS）. Bony fusion was assessed by followed-up CT three-dimentional reconstruction. Results Exiting nerve root paralysis occurred in 1 case after operation, and released at 4 weeks after operation; no aggravation of nerve damage was observed in the other patients. The incisions primarily healed. All the patients were followed up 12-48 months （mean, 25 months）. The slip percentage, the lumbosacral angle, and VAS score of lower extremity were improved from 72%士 10%, （18.2 士 3.5）°, and 7.0 ＋ 1.5 at preoperation to 12% ＋ 6%, （-7.3 士 2.9）°, and 1.5 士 1.3 at 12 months after operation respectively, all showing significantdifferences （P 〈 0.05）. Osteosynthesis was seen at the bone grafting area by CT three-dimentional reconstruction at 12 monthsafter operation. No breakage of screw and rod or reduction loss occurred. Conclusion It can obtain satisfactory clinical result to use spinal canal decompression by posterior approach, the Schanz screw fLxation of the slipped vertebrae, the intervertebral and posterolateral fusion for severe spondylolisthesis. The risk of nerve stretch injury can be prevented by choosing the lowest height of intervertebral cage, modulating the reductive degree of slipped vertebrae according to the strain of exiting spinal root, and correcting lumbosacral kyphosis.