腰椎短节段融合术后坐-立位相邻节段序列变化研究

Analysis of unfused adjacent segment lordosis in standing and sitting positions for patients with short-segments lumbar fusion

目的:观察腰椎短节段融合术后不同功能体位脊柱-骨盆矢状位序列的变化,探讨坐位下相邻未融合节段矢状位序列的调节机制。方法:2010年9月~2012年2月行腰椎短节段融合术的63例患者纳入研究,其中男30例,女33例,末次随访时年龄为61.6±11.0岁(31.0~81.0岁),随访时间为82.0±7.3个月(68.0~94.0个月)。共39例患者融合至S1,其中3例为L5~S1固定融合,20例为L4~S1固定融合,15例为L3~S1固定融合,1例为L2~S1固定融合;24例未融合至S1,其中13例为L3~L5固定融合,5例为L4~L5固定融合,6例为L2~L5固定融合。均行术前站立位、末次随访站立位-端坐位-自然坐位全脊柱正侧位X线片检查,通过院内PACS系统,测量术前、末次随访时的脊柱-骨盆矢状位参数,包括骨盆入射角(PI)、骨盆倾斜角(PT)、骶骨倾斜角(SS)、腰椎前凸角(LL)、固定节段前凸角(FSL)、胸椎后凸角(TK)、上相邻前凸角(URL)、下相邻前凸角(LRL)及T1骨盆角(TPA)。采用单因素方差分析,对比不同体位脊柱-骨盆矢状位参数变化;运用Pearson相关分析,分析站立位、自然坐位情况下URL、LRL与其他矢状位参数的相关性,检验水准α=0.05。结果:当体位由站立位向坐位转变后,矢状位参数会出现显著的变化。对于未融合至S1的患者,从站立位变为端坐位后,LL显著减小、TPA显著增大(P<0.05);由端坐位变为自然坐位后,LL进一步显著减小、TPA进一步显著增大(P<0.05),SS、URL、LRL显著减小(P<0.05),PT显著增加(P<0.05)。对于融合至S1的患者,从站立位变为端坐位后,LL、URL显著减小(P<0.05),TPA显著增大(P<0.05);由端坐位变为自然坐位后,LL、URL进一步显著减小(P<0.05),TPA进一步显著增大(P<0.05),SS显著减小、PT显著增加(P<0.05)。在站立位时,URL与PI、SS、FSL、LL有显著相关性(P<0.05)。自然坐位后,URL与FSL无显著相关性(P=0.388),URL与PI、SS、TK、LL有显著相关性(P<0.05),LRL与PT、SS、LL有显著相关性(P<0.05)。结论:腰椎短节段融合术后患者坐位时矢状位序列会发生显著改变,表现为骨盆后倾旋转,腰椎前凸变得平直,尤其是上、下相邻节段。自然坐位时,URL主要依靠骨盆与胸椎后凸角度的调节。自然坐位下URL、LRL显著减小的特点,可能是腰椎融合术后远期交界区并发症的病因之一。

Objectives:This study aimed to investigate the differences in spinopelvic sagittal alignment of patients with posterior lumbar fusion among different functional postures.The variation of spinopelvic sagittal alignment,especially the unfused adjacent segments lordosis in sitting position will be fully studied.Methods:This was a radiological analysis using full-spine standing,erect and natural sitting lateral radiographs of patients with posterior lumbar fusion before surgery and in final follow-up.A total of 63 patients who received lumbar fusions with short segments between September 2010 and February 2012(30 males,33 females;mean age 61.6±11.0 years;mean follow-up duration time 82.0±7.3 months) were enrolled.39 patients had lumbosacral fusion,including 3 patients with L5-S1 fusion,20 patients with L4-S1 fusion,15 patients with L3-S1 fusion,and 1 patient with L2-S1 fusion.24 patients had lumbar floating fusion,including 13 patients with L3-L5 fusion,5 patients with L4-L5 fusion,and 6 patients with L2-L5 fusion.Pelvic and spinal parameters were measured,including pelvic incidence(PI),pelvic tilt(PT),sacral slope(SS),lumbar lordosis(LL),fusion segment lordosis(FSL),upper residual lordosis(URL),lower residual lordosis(LRL),thoracic kyphosis(TK)and T1-pelvic angle(TPA).Using one-way ANOVA,the parameters were compared between standing and erect sitting posture,erect and natural sitting posture.The changes of sagittal alignment in different postures were discussed.Using Pearson’s correlation test,relationships between residual lordosis and other parameters were discussed according to different positions.Results:When moving from standing to sitting position,sagittal parameters were changed significantly.For patients with lumbar floating fusions,when changing from standing to erect sitting,increased TP A and decreased LL were observed(P<0.05).When changing to natural sitting,increasing TP A and decreasing LL were further observed(P<0.05),SS,URL and LRL were significantly decreased(P<0.05),and PT was significantly increased(P<0.05).For patients with lumbosacral fusions,when changing from standing to erect sitting,increased TPA,decreased LL and URL were observed(P<0.05).When changing to natural sitting,increasing TPA and decreasing LL and URL were further observed(P<0.05),SS was significantly decreased(P<0.05),and PT was significantly increased(P<0.05).In standing position,the correlations between URL-PI and URL-FSL existed(P<0.05).But in natural sitting position,the correlation in URL-FSL was lost(P=0.388),URL had close relationship with TK(P<0.05).Correlations between LRL-SS,LRL-PT and LRL-LL existed(P<0.05).Conclusions:In a natural sitting posture,the total spine becomes kyphotic comprising the thoracic,the unfused lumbar and fused lumbar spine.The unfused lumbar segments are more straightened in sitting position.In natural sitting position,the URL depends more on the adjustment of TK.The characteristics of unfused segments lordosis in natural sitting position may provide information for one of the possible causes of proximal and distal junctional failure or adjacent segment degeneration.