脊柱侧后凸/后凸畸形SRS-Schwab四级截骨术后近端交界性后凸的危险因素分析

Risk factors for proximal junctional kyphosis after SRS-Schwab grade 4 osteotomy in patients with spine kyphoscoliosis/kyphosis

目的:探讨脊柱侧后凸/后凸畸形患者SRS-Schwab四级截骨术后发生近端交界性后凸(proximal junctional kyphosis,PJK)的相关危险因素。方法:回顾性分析2011年5月~2015年12月于我院行SRS-Schwab四级截骨手术且具有完整临床及影像学资料的46例脊柱侧后凸/后凸畸形患者,其中男性24例,女性22例,手术时年龄23.1±19.7岁。记录患者体重指数、融合节段、最上端固定椎(upper instrumented vertebra,UIV)位置及置钉密度等。测量术前、术后3个月及末次随访时的胸椎后凸角(thoracic kyphosis,TK)、腰椎前凸角(lumbar lordosis,LL)、骨盆入射角(pelvic incidence,PI)、局部后凸角(segmental kyphosis,SK)、主弯Cobb角(main curve,MC)、矢状面平衡(sagittal vertical axis,SVA)及近端交界角(proximal junctional angle,PJA)。根据患者术后是否发生PJK分为非PJK组和PJK组,采用t检验、χ^(2)检验或Fisher精确检验对比两组临床资料及影像学参数,利用多因素Logistic回归分析确定PJK发生的危险因素。结果:46例患者术后随访24~63个月(36.9±13.4个月),其中11例(23.9%)发生PJK,以Ⅰ型PJK(8/11)最为常见,8例发生于术后6个月内。PJK组和非PJK组患者性别、年龄、随访时间、体重指数、融合节段、骨密度、置钉密度、UIV位置均无统计学差异(P>0.05)。PJK组患者术前TK>40°(6/11)和SK矫正>30°(7/11)的比例均高于非PJK组(P<0.05)。两组患者间术前PJA、LL、MC、PI、SVA和术后及末次随访时TK、LL、MC、SK、PI、SVA改变均无统计学差异(P>0.05)。回归分析结果显示术后SK矫正>30°(OR=7.000,95%CI=1.591-30.800,P=0.010)是PJK发生的独立危险因素。PJK组术前PJA为7.5°±3.0°,术后3个月为20.8°±4.1°,末次随访时为22.0°±4.5°,交界性后凸未见明显加重。结论:脊柱侧后凸/后凸畸形患者SRS-Schwab四级截骨术后PJK发生率为23.9%,其主要发生于术后6个月内,脊柱后凸畸形过度矫正是其独立危险因素。

Objectives:To investigate the risk factors for proximal junctional kyphosis(PJK)in patients with kyphoscoliosis/kyphosis underwent SRS-Schwab grade 4 osteotomy.Methods:A retrospective review of 46 patients with spine kyphoscoliosis/kyphosis who underwent SRS-Schwab grade 4 osteotomy between May 2011 and December 2015 was performed,including 24 males and 22 females,with an average age of 23.1±19.7 years.Body mass index,fusion segment,upper instrumented vertebra(UIV)and implant density were recorded.The spine-pelvic parameters including thoracic kyphosis(TK),lumbar lordosis(LL),pelvic incidence(PI),seg-mental kyphosis(SK),main curve(MC),sagittal vertical axis(SVA)and proximal junctional angle(PJA)were mea-sured pre-and post-operationally and at last follow up.Patients were divided into PJK group and non-PJK group.Comparison of clinical and radiographic data was conducted between the 2 groups by Student′s t-test and Chi-square test or Fisher′s exact test.Multivariate Logistic regression analysis was used to determine the risk factors of PJK.Results:The average follow-up period of 46 patients was 36.9±13.4 months,during which PJK occurred in 11 cases(23.8%).8 patients developed PJK during the first six months after surgery and the most common type of PJK was typeⅠ(8/11).There was no significant difference in gender,age,follow-up,body mass index,fusion segment,bone mineral density,implant density and UIV between two groups(all P>0.05).Compared with the non-PJK group,the PJK group showed higher rate of pre-operative TK>40°and SK improvement>30°(all P<0.05).No significant difference was detected between both groups in pre-operative PJA,LL,MC,PI,SVA,and TK,LL,MC,SK,PI,SVA changes after operation and at the last follow-up(all P>0.05).Logistic regression analysis showed that SK improvement>30°(OR=7.000,95%CI=1.591-30.800,P=0.010)was independent risk factor associated with PJK.The average PJA increased from7.5°±3.0°to 20.8°±4.1°at 3 months after surgery.At the final follow-up in PJK group,PJA averaged 22.0°±4.5°and no significant progression of PJA was observed.Conclusions:The incidence of PJK after SRSSchwab grade 4 osteotomy in patients with spine kyphoscoliosis/kyphosis was 23.9%,which mainly occurred within 6 months,and over correction of kyphosis is one of the high risk factors.