后路枕颈融合术治疗寰枢椎脱位对颅颈矢状面序列的影响

关键词：寰椎  枢椎  脱位  内固定器  肌肉骨骼平衡  摄影测量法

Keywords:Atlas  Axis  Dislocations  Internal fixators  Musculoskeletal equilibrium  Photogrammetry

摘要：

      目的 探讨后路枕颈融合术（OCF）治疗寰枢椎脱位对颅颈矢状面序列的影响。方法 回顾性分析2009年1月—2024年6月新疆医科大学第一附属医院采用OCF治疗的寰枢椎脱位患者86例（OCF组），匹配同时期健康志愿者86名（对照组），测量2组颅颈矢状面序列参数，包括头颅矢状面参数［颏额垂线角（CBVA）、颅倾斜角（CS）］，颈椎基底部矢状面参数［T₁倾斜角、胸廓入射角（TIA）、颈部倾斜角（NT）］，颈椎矢状面参数［枕寰角（O-C₁A）、枕颈角（O-C₂A）、C_1~2 Cobb角、O-C₇ Cobb角、C_1~7 Cobb角、C_2~7 Cobb角、C_2~7矢状面垂直轴（CSVA）、C₂倾斜角］。手术前后采用视觉模拟量表（VAS）评分、改良日本骨科学会（mJOA）评分、颈椎功能障碍指数（NDI）评估颈部疼痛程度及颈椎功能。结果 末次随访时，OCF组术后VAS评分、mJOA评分和NDI较术前明显改善，O-C₂A、C_1~2 Cobb角和CSVA较术前显著增大，C_2~7 Cobb角显著减小，C₂倾斜角由后倾变为前倾，差异均有统计学意义（P<0.05）。OCF组术前和末次随访时CBVA、CS、O-C₂A、C_1~2 Cobb角、C_2~7 Cobb角、C₂倾斜角与对照组比较，差异均有统计学意义（P<0.05）；O-C₁A、O-C₇ Cobb角、C_1~7 Cobb角和CSVA仅术前与对照组差异有统计学意义（P<0.05）。Pearson相关分析结果表明，O-C₂A变化值与C_1~2 Cobb角变化值呈正相关，与C₂倾斜角变化值、C_2~7 Cobb角变化值和CSVA变化值呈负相关。结论 寰枢椎脱位患者接受OCF治疗后，枕颈交界区（O-C₂A、C_1~2 Cobb角）曲度恢复至前凸，下颈椎代偿性前凸（C_2~7 Cobb）减小，CSVA前移，C₂倾斜角前倾。OCF应确定合适的O-C₂A融合角度，避免矫正不足或过度矫正导致颅颈椎代偿失衡。

Abstract:

      Objective To investigate the effect of posterior occipitocervical fusion（OCF） on the craniocervical sagittal plane sequence in patients with atlantoaxial dislocation. Methods From January 2009 to June 2024，a retrospective analysis was conducted on 86 patients with atlantoaxial dislocation treated with OCF（OCF group）at First Affiliated Hospital of Xinjiang Medical University，and 86 healthy volunteers during the same period were matched（control group）. The sagittal plane sequence parameters of the craniocervical region in the 2 groups，including the craniocervical sagittal plane parameters（chin-brow vertical angle［CBVA］，cranial slope［CS］），the cervical-base sagittal plane parameters（T₁ slope，thoracic inlet angle（［TIA］，neck tilt［NT］），and the cervical sagittal plane parameters［atlanto-occipital angle［O-C₁A］，occipito-cervical angle［O-C₂A］，C_1-2 Cobb angle，O-C₇ Cobb angle，C_1-7 Cobb angle，C_2-7 sagittal vertical axis［CSVA］，C₂ slope） were measured. The pain visual analogue scale（VAS） score，modified Japanese Orthopaedic Association（mJOA） score，and cervical dysfunction index（NDI） were used to assess the intensity of neck pain and cervical function. Results At the final follow-up，the OCF group showed significant improvements in postoperative VAS scores，mJOA scores and NDI compared to preoperative values，while O-C₂A，C_1-2 Cobb angle and CSVA increased significantly，and C_2-7 Cobb angle decreased significantly，and the C₂ slope shifted from posterior to anterior tilt. All these differences were statistically significant（P<0.05）. The OCF group exhibited statistically significant differences compared to the control group in preoperative and final follow-up values for CBVA，CS，O-C₂A，C_1-2 Cobb angle，C_2-7 Cobb angle，and C₂ slope（P<0.05）. O-C₁A，O-C₇ Cobb angle，C_1-7 Cobb angle and CSVA showed statistically significant differences only in the preoperative period compared to the control group（P<0.05）. Pearson correlation analysis revealed that the change in O-C₂A was positively correlated with the change in C_1-2 Cobb angle，and negatively correlated with the changes in C₂ slope，C_2-7 Cobb angle and CSVA. Conclusions After OCF treatment，patients with atlantoaxial dislocation exhibited restored lordosis at the occipitocervical junction（O-C₂A and C_1-2 Cobb angle），reduced compensatory lordosis in the lower cervical spine（C_2-7 Cobb angle），anterior shift of CSVA，and anterior inclination of the C₂ slope. OCF should determine an appropriate O-C₂A fusion angle to avoid under correction or overcorrection，which could lead to compensatory imbalance in the craniocervical region.