颅底凹陷症患者枕颈融合术中枕颈角和后枕颈角的选择策略

Selection strategy of occipito-C2 angle and posterior occipitocervical angle in patients with basilar invagination during occipitocervical fusion

目的:探讨颅底凹陷症患者枕颈融合术中枕颈角(OC2A)和后枕颈角(POCA)的选择策略。方法:回顾性分析2012年1月~2017年1月在我科行枕颈融合术的颅底凹陷症(BI)患者42例;男性15例、女性27例,年龄47.6±10.7岁,身高164.8±11.5cm,体重61.5±8.8kg,体重指数(BMI)22.6±3.1kg/m~2;合并寰枕融合13例、寰椎发育不良8例、齿状突畸形5例、寰枕融合+Klippel-Feil(K-F)综合征16例。根据性别和年龄基线匹配纳入84例健康体检者;男30例,女54例,年龄50.6±9.5岁,身高166.1±12.4cm,体重63.8±9.6kg,BMI 22.1±3.9kg/m~2。测量健康人群OC2A和POCA,BI患者术前、术后即刻及末次随访时OC2A、POCA和下颈椎前凸角(CSA),以及术后即刻和末次随访时下颈椎椎间盘和椎体高度比(S值)。获得健康组OC2A和POCA的均值和95%置信区间(95%confidence intervals,95%CI),根据术后即刻OC2A和POCA选择是否在健康人群95%CI,将BI患者分为正常角度组(OC2A和POCA均在健康人群95%CI)和非正常角度组。获得两组患者术后即刻OC2A和POCA与术前的差值(d-OC2A和d-POCA);记录两组患者术前和末次随访疼痛视觉评分(VAS)评分、日本骨科协会(JOA)评分、颈椎功能障碍指数(NDI)以及末次随访时下颈椎前凸角丢失度数(dCSA)和S差值(dS)。结果:健康人群OC2A和POCA值分别为14.8°±4.5°和108.1°±8.6°,95%CI分别为8.6°~21.1°和91.2°~121.8°。BI患者术前的OC2A、POCA和CSA分别为5.6°±4.3°、123.8°±10.4°和25.7°±9.5°。BI患者中,正常角度组(n=26)术后即刻OC2A和POCA分别为12.9°±3.2°,111.9°±7.2°,非正常角度组(n=16)术后即刻OC2A和POCA分别为6.1°±2.4°和120.4°±9.4°。正常角度组d-OCA和d-POCA分别为10.6°±3.5°(6.5°~18.8°)和-8.8°±5.2°(-24.0°~5.5°),非正常角度组d-OCA和d-POCA分别为3.8°±4.1°(-4.5°~9.5°)和-6.4°±4.2°(-18.0°~7.8°),两组之间术后即刻OC2A、POCA以及d-OCA差异有统计学意义(P<0.05)。非正常角度组患者末次随访VAS评分、JOA评分和NDI优于正常角度组,差异有统计学意义(P<0.05);且非正常角度组dCSA和dS值低于正常角度组(P<0.05)。结论:BI患者术前OC2A和POCA与正常人群存在差异,基于患者术前OC2A和POCA的基础值,术中OC2A选择低于正常范围更接近此类患者术前的枕颈区和下颈椎的生物力学环境,可减少术后下颈椎代偿性的异常活动和退变,提高患者临床疗效。

Objectives:To explore the proper selection strategy of occipito-C2(OC2A)and posterior occipitocervical angle(POCA)in in patients with basilar invagination during occipitocervical fusion(OCF).Methods:Data of 42 patients with basilar invagination(BI)who underwent OCF from January 2012 to January 2017 were reviewed.15 males and 27 females with an average age of 47.6±10.7 years were included.And the height of patients was 164.8±11.5 cm,weight was 61.5±8.8 kg,and body mass index(BMI)was 22.6±3.1 kg/m2.Among them,BI combined with atlantooccipital fusion in 13 cases,atlas dysplasia in 8 cases,odontoid malformation in 5 cases,and atlantooccipital fusion+Klippel-Feil syndrome in 16 cases.Eighty-four healthy subjects were selected according to the baseline matching of gender and age of patients with BI,30 males and 84 females with an average age of 50.6±9.5 years were included.The height of healthy subjects was166.1±12.4 cm,weight was 63.8±9.6 kg,and BMI was 22.1±3.9 kg/m2.OC2A and POCA of the healthy subjects were measured.OC2A,POCA,cervical spinal angle(CSA),and theheight ratio of lower cervical intervertebral disc to vertebral body(S value)were measured preoperatively,immediately after surgery,and at the final follow-up in patients with BI.The mean value and 95%confidence intervals(95%CI)of OC2A and POCA in the healthy subjects were obtained.The patients with BI were divided into normal angle group(OC2A and POCA both in 95%CI of healthy group)and abnormal angle group according to the value of OC2A and POCA immediately after surgery.The difference of OC2A(d-OC2A)and POCA(d-POCA)from post-operation immediately to pre-operation were obtained.The preoperative and final follow-up visual analog scale(VAS),Japanese Orthopedic Association score(JOA),neck disability index(NDI),and dCSA/dS(CSA/S from immediately after surgery to the final follow-up)were recorded.Results:The values of OC2A and POCA were 14.8°±4.5°and 108.1°±8.6°in the healthy,respectively,and the respective 95%confidence intervals(CIs)were 8.6°-21.1°and 91.2°-121.8°as the normal range.The preoperative OC2A,POCA and CSA of patients were 5.6°±4.3°,123.8°±10.4°and 25.7°±9.5°,respectively.The values of OC2A and POCA immediately after surgeryin normal angle group(n=26)were 12.9°±3.2°,111.9°±7.2°.In abnormal angle group(n=16),the postoperative OC2A and POCA were 6.1°±2.4°and 120.4°±9.4°,respectively.The d-OCA and d-POCA of normal angle group were10.6°±3.5°(6.5°-18.8°)and-8.8°±5.2°(-24.0°-5.5°),and those values of the abnormal angle group were 3.8°±4.1°(-4.5°-9.5°)and-6.4°±4.2°(-18.0°-7.8°),respectively.And the difference of postoperative OC2A,POCAand d-OC2A between the two groupswere statistically significant(P<0.05).The VAS,JOA,and NDI of abnormal angle group at the final follow-up were significantly better than those in the normal angle group(P<0.05),and the normal angle group showed statistically greater dCSA and dS than those in the abnormal angle group(P<0.05).Conclusions:Preoperative OC2A and POCA in BI patients are different from those in the normal population.Based on the values of OC2A and POCA in patients before surgery,the selection of OC2A is lower than the normal range and closer to the biomechanical environment of occipitocervical region and lower cervical spine before operation which can reduce the postoperative compensatory abnormal activities and degeneration of the lower cervical spine and improve the clinical efficacy of patients.