腰椎单侧小关节突分级切除的生物力学影响及微创外科的修复与重建

The biomechanical change of lumbar unilateral graded facetectomy and strategies of its microsurgical reconstruction:report of 23 cases

目的通过生物力学实验以研究腰椎单侧小关节突分级切除后对稳定性的影响,并通过临床研究以评价内窥镜下单侧小关节突切除、腰椎间植骨融合、单侧椎弓根螺钉内固术的初划临床结果。方法选用5具新鲜成人尸体脊柱制成5个 L4～L5椎功能单位,以研究小关节突分级切除后对腰椎前屈、后伸、侧屈及轴向旋转运动范围的影响。并对23例手术患者的初期临床结果进行评价。其中男16例,女7例;年龄32～74岁,平均47.7岁。手术在内窥镜下单侧小关节突切除、椎间盘摘除、神经根松解和减压、自体松质骨椎间植骨、单枚椎间融合器斜向椎间植入,单侧椎弓根螺钉内固定。结果腰椎单侧小关节突分级切除对早期腰椎的前屈和后伸活动无明显的影响。当单侧小关节突切除范围超过1/2时,对腰椎侧弯和轴向旋转活动有明显的影响(均 P<0.05)。本组23例患者,疗效评定按照 VAS 疼痛目测评分法、ODI 功能障碍指数和 Nakai 分级评定。根据 Nakai 分级,优15例(65.2%),良6例(26.1%),可2例(8.7%)。优良率91.3%。植骨融合率为95.6%。结论腰椎单侧小关节突切除范围超过1/2时,显著影响腰椎的稳定性。内窥镜下经单侧神经管减压、椎间植骨融合、单侧椎弓根螺钉内固定是一种可供临床选择的微创外科术式。

Objective To study the effects of unilateral graded facetectomy on lumbar stability through biomechanical analysis. The primary clinical results of unilateral facetectomy, posterior lumbar interbody fusion and unilateral pedicle screw instrumentation using X-tube system were also evaluated. Methods 5 functional spinal units （ FSU ） from fresh cadavers of 5 adults were made, divided into 5 groups to remain intact, or with the lateral 1/4, 1/2, or 3/4 or the whole of the left IA/5 articular process, and then put in the biomechanical testing apparatus to evaluate the effects of operation on the lumbar motion range of flexion, extension, lateral bending and axial rotation. Twenty-three patients, 16 males and 7 females, aged 47. 7 （ 32 - 74 ）, underwent unilateral facetectomy, posterior lumbar interbody fusion, and unilateral pedicle screw instrumentation using X-tube system. The clinical outcomes of the 23 patients were assessed by use of the visual analog score （ VAS）, Oswestry disability index （ ODI ）, and Nakai criteria. Result The experiment of the 5 FSUs showed that no significantly negative effects on the change in lumbar motion range of flexion, extension after unilateral graded facetectomy （ all P 〉 0. 05 ）, and the stability of lateral bending and axial rotation had been greatly affected with the range of graded facetectomy exceeding 1/2（P 〈0.05）. According to the Nakai criteria, the clinical effect was excellent in 15 cases （65.2%）, good in 6 cases （26. 1% ）, and fair in 2 cases （8. 7% ）. The excellent and good cases accounted for 91.3% with a fusion rate of 95.6%. Conclusion The lumbar stability is significantly affected if the range of graded facetectomy exceeds 1/2. The use of procedures of unilateral facetectomy, diskectomy, spinal nerve root decompression, autologous bone grafting, and unilateral pedicle screw fixation using X-tube is an optional strategy for minimally invasive spine technique.