腰椎经后路椎体间融合后单边或双边固定对邻近节段退变的影响

背景：在行后路椎体融合内固定术中,椎弓根钉置入不可避免会损伤邻近关节突关节。目前一致认为单边固定因保留一侧关节突关节可明显降低邻近节段退变的发生率,但仍缺乏对邻近节段退变的影响因素及不同节段退变发生率的长期随访研究。目的：对比经后路椎体间融合术（posterior lumbar interbody fusion,PLIF）后单边或双边椎弓根螺钉固定对邻近节段退变的影响。方法：2006年2月至2007年12月,101例行PLIF手术的L4-L5椎间盘突出症患者纳入本研究。采用单边固定42例,双边固定59例。所有患者术后随访时间均超过5年。邻近节段分为三个节段：第1个近端邻近节段、第2个近端邻近节段及远端邻近节段。依据末次随访的影像学资料评估邻近节段退变的情况,并记录末次随访时的ODI评分评价腰椎功能。结果：单边固定组第1个近端邻近节段、第2个近端邻近节段及远端邻近节段退变的发生率分别为57.1%（24/42）、45.2%（19/42）、38.1%（16/42）;双边固定组第1个近端邻近节段、第2个近端邻近节段及远端邻近节段退变的发生率分别为72.9%（43/59）、68.0%（40/59）、50.8%（30/59）。两组第1个近端邻近节段和远端邻近节段退变发生率无统计学差异,而第2个近端邻近节段退变发生率具有统计学差异。末次随访时单边固定组和双边固定组的ODI评分分别为25.6±5.9、28.4±5.2,两组具有显著统计学差异（t=-2.503,P=0.014）。结论：对于行腰椎后路减压融合术的单节段腰椎间盘突出症患者,单边固定者邻近节段退变发生率低于双边固定者,尤其对于第2个近端邻近退变节段的患者。

Comparative study of adjacent segment degeneration after posterior lumbar interbody fusion with unilateral or bilateral pedicle screw instrumentation

Background： In the instrumented fusion, adjacent facet joint violation or impingement by pedicle screws is unavoidable.Unilateral pedicle screw instrumentation is thought to reduce adjacent segment degeneration（ASD） by preventing contralateral cephalad adjacent facet joint from injury by pedicle screw insertion. However, there are few studies on long-term followup comparative study on ASD between unilateral and bilateral pedicle screw fusion.Objective： To compare ASD after posterior lumbar interbody fusion（PLIF） using either unilateral or bilateral pedicle screw instrumentation for patients with L4-L5 intervertebral disc herniation.Methods： A total of 101 patients with L4-L5 intervertebral disc herniation were treated with PLIF between February 2006 and December 2007 and enrolled in the study. There were 42 cases with unilateral fixation and 59 cases with bilateral fixation. The follow-up period of all patients were more than 5 years. Radiologic ASD was evaluated at three segments： the first cephalad adjacent segment, the second cephalad adjacent segment, and caudal adjacent segment. ODI score was used to evaluate vertebral function at the last follow-up.Results： In the unilateral fixation group, the incidence of ASD of the first cephalad adjacent segment, second cephalad adjacent segment and caudal adjacent segment was 57.1%（24/42）, 45.2%（19/42） and 38.1%（16/42））, respectively. In the bilateral fixation group, the incidence of ASD of the three segments was 72.9%（43/59）, 68.0%（40/59） and 50.8%（30/59）, respectively. There were no significant differences in the incidences of ASD of the first cephalad and caudal adjacent segmentbetween groups, while significant difference was found in the second cephalad adjacent segment degeneration between two groups. ODI score was 25.6±5.9 in the unilateral fixation group and 28.4±5.2 in the bilateral fixation group（t=-2.503, P=0.014）.Conclusions： As compared with bilateral fixation, there is a lower incidence of radiologic ASD