先天性腰骶段脊柱畸形长节段固定术后冠状面失平衡的原因分析

Risk factors analysis of coronal imbalance after posterior correction of congenital lumbosacral deformity with long segmental fixation

目的 :总结分析先天性腰骶段脊柱畸形行后路长节段固定术后冠状面失平衡原因及预防措施。方法 :回顾性分析2007年5月～2017年5月于我院行后路截骨联合长节段固定矫形术治疗的23例先天性腰骶段脊柱畸形患者的临床资料,其中男6例,女17例,平均年龄13.2±2.8岁(10～18岁),平均随访时间38.2±8.4个月(24～96个月)。收集患者畸形节段、畸形类型、融合节段、躯干倾斜及术前、术后6个月及末次随访时站立位全脊柱X线、Bending位X线、双下肢负重位全长X线片及术前、末次随访时的简体中文版SRS-22评分,测量原发弯和继发弯Cobb角,脊柱柔韧度指数(flexibility of the structural curve,FSC),骶骨倾斜(sacral obliquity,SO),锁骨角(clavicle angle,CA),冠状面平衡距离(coronal balance distance,CBD)与双下肢全长等指标,根据患者矫形术后是否出现冠状面失平衡,将患者分为平衡组与失衡组。冠状面失平衡诊断标准:C7铅垂线(C7plumb line,C7PL)偏距骶骨中垂线(center sacral vertical line,CSVL)>2cm。应用卡方检验、t检验,分析术后冠状面失平衡的可能原因并提出相应预防措施。结果:23例患者平均融合节段数7.4±2.3节(5～12节)。术前平均原发弯Cobb角40.25°±10.6°,末次随访时为12.4°±5.2°,平均矫正率(69.1±8.7)%。术前平均继发弯Cobb角35.5°±8.5°,末次随访时为13.1°±5.0°,平均矫正率(63.1±7.9)%。术后冠状面失衡组5例,发生率为21.7%。男2例,女3例。L5半椎体1例,L5半椎体合并L4蝴蝶椎1例,S1半椎体1例,L5横突肥大形成假关节1例,L5楔形椎1例。失衡组中,2例发生S1断钉,1例行翻修手术治疗,1例行支具治疗。两组比较,继发弯柔韧指数、术前躯干偏移、上固定椎位置、下固定椎位置、末次随访冠状面平衡距离(1.0±0.8cm vs 3.0±0.7cm)、术后6个月骶骨倾斜角(3.5°±3.2°vs 15.2°±14.2°)、末次随访锁骨角(3.6±3.6cm vs 15.0±13.3cm)、SRS-22评分末次随访自我形象维度(3.9±0.6 vs 3.7±0.7)、治疗满意度(4.5±0.2 vs 2.6±0.6)、心理健康(4.1±0.4 vs 3.2±0.5)及总评分(15.1±2.8 vs 17.8±2.2)有统计学差异(P<0.05)。性别构成比(4/14 vs 2/3)、手术年龄(12.6±3.8 vs 14.2±2.6)、固定节段数(8.3±3.7 vs 6.8±1.9)、术前原发弯Cobb角(35.2°±17.1°vs 37.6°±4.6°)、术后6个月原发弯Cobb角(12.6°±5.6°vs 16.6°±5.9°)、末次随访原发弯Cobb角(12.0°±6.2°vs 16.4°±5.9°)、术前继发弯Cobb角(37.3°±10.7°vs 38.4°±5.4°)、术后继发弯Cobb角(15.5°±4.6°vs 12.0°±7.5°)、末次随访继发弯Cobb角(14.1°±5.0°vs 12.6°±7.5°)、术前冠状面平衡距离(2.1±2.7mm vs 2.9±1.9mm)、术后6个月冠状面平衡距离(0.9±1.2mm vs 1.7±1.1mm)、术前锁骨角(2.0°±0.9°vs 1.2°±1.1°)、术后6个月锁骨角(1.5°±1.2°vs 2.6°±2.4°)、术前骶骨倾斜角(1.1°±1.0°vs 4.0°±2.5°)、SRS-22量表术前功能/活动(4.1±0.5 vs 3.9±0.6)、疼痛(3.4±0.4 vs 3.8±0.4)、自我形象(3.4±0.7 vs 3.2±0.7)、心理健康维度(3.5±0.3 vs 3.6±0.7)、末次随访功能/活动维度(3.9±0.5 vs3.8±0.5)、疼痛维度评分(3.9±0.4 vs 3.7±0.9)均无统计学差异(P>0.05)。结论:腰骶段畸形行长节段固定矫形术可获得良好的矫形效果,但存在一定的术后冠状面失平衡风险,其原因可能与截骨不彻底、矫形策略及固定椎选择不当有关。

Objectives: To analyze the clinical feature, risk factors and preventions of coronal imbalance after posterior correction of congenital lumbosacral deformity with long segmental fixation. Methods: 23 patients with congenital lumbosacral deformity received osteotomy and long segmental pedicle screw fixation and correction via posterior approach alone between May 2007 to May 2017 in our hospital were analyzed. There were 6 males and 17 females with an average age 13.2±2.8 years old, and the average follow-up was 38.2±8.4 months. Deformity segments, type, fusion segments, the simplified Chinese version of SRS-22 questionnaire, imaging parameters of AP film of standing full spine X ray, bending X ray and lower extremity weight-bearing full-length X ray were collected. The main Cobb angle, cranial curve Cobb angle, bending Cobb angle, sacral obliquity, clavicle angle, coronal balance distance, double total length lower extremities were measured. All patients were categorized into coronal balance group and imbalance group according to the diagnosis criteria of coronal imbalance which was defined as the distance from C7PL to CSVL more than 2cm. Results: The average fusion segments were 7.4±2.3. The average pre-operative main curve Cobb angle was 40.25°±10.6° and corrected to 12.4°±5.2° at final follow-up. The correction rate was (69.1±8.7)%. The average pre-operative compensatory cranial curve Cobb angle was 35.5°±8.5° before surgery and corrected to 13.1°±5.0° at final follow-up, the correction rate was (63.1±7.9)%. 5 cases including 2 boys and 3 girls occurred postoperative coronal imbalance(21.7%) during follow-up. The pathological classification included L5 hemivertebra in 2 cases, S1 hemivertebra in 1 case, L5 wedge vertebra in 1 case and L5 hypertrophy transverse in 1 case, respectively. In imbalance group, 2 cases had pedicle screw breakages at S1, 1 of the 2 cases received revision operation, the other accepted brace therapy. There were significant differences between the two groups in cranial curve FSC, pre-operative trunk shift, UIV position, LIV position, final follow-up CBD(1.0±0.8cm vs 3.0±0.7cm), post-operative clavicle angle(3.5°±3.2° vs 15.2°±14.2°), final follow-up clavicle angle(3.6°±3.6° vs 15.0°±13.3°), and final follow-up self-image domain(3.9±0.6 vs 3.7±0.7), final follow-up treatment satisfaction domain(4.5±0.2 vs 2.6±0.6), final follow-up mental domain(4.1±0.4 vs 3.2±0.5), total score(15.1±2.8 vs 17.8±2.2) in SRS-22. There were no significance differences between two groups in gender(4/14 vs 2/3), average age(12.6±3.8 vs 14.2±2.6), fusion segments(8.3±3.7 vs 6.8±1.9), pre-operative main Cobb angle(35.2°±17.1° vs 37.6°±4.6°), post-operative main Cobb angle(12.6°±5.6° vs 16.6°±5.9°), final follow-up Cobb angle(12.0°±6.2° vs 16.4°±5.9°), pre-operative cranial curve Cobb angle(37.3°±10.7° vs 38.4°±5.4°), post-operative cranial curve Cobb angle(15.5°±4.6° vs 12.0°±7.5°), final follow-up cranial curve Cobb angle(14.1°±5.0° vs 12.6°±7.5°), pre-operative CBD(2.1±2.7 vs 2.9±1.9), post-operative CBD(0.9±1.2 vs 1.7±1.1), pre-operative clavicle angle(2.0±0.9 vs 1.2±1.1), post-operative clavicle angle(1.5±1.2 vs 2.6±2.4), pre-operative sacral obliquity angle(1.1±1.0 vs 4.0±2.5), and pre-operative fuction domain(4.1±0.5 vs 3.9±0.6), pre-operative pain domain(3.4±0.4 vs 3.8±0.4), pre-operative self-image domain(3.4±0.7 vs 3.2±0.7), pre-operative mental(3.5±0.3 vs 3.6±0.7), final follow-up fuction domain(3.9±0.5 vs 3.8±0.5), final follow-up pain domain(3.9±0.4 vs 3.7±0.9) in SRS-22 between the two groups in univariable test(P >0.05). Conclusions: Patients with congenital lumbosacral deformity receiving long segmental fixation has optimistic deformity correction. Coronal imbalance after sugery can negatively affect life quality. The risk factors could be incomplete osteotomy, improper orthopedic strategy and inappropriate segments selection.