Objective: To investigate the imaging characteristics of cervical kyphosis and spinal cord compression in cervical spondylotic myelopathy (CSM) with cervical kyphosis and the influence on effectiveness.
Methods: The clinical data of 36 patients with single-segment CSM with cervical kyphosis who were admitted between January 2020 and December 2022 and met the selection criteria were retrospectively analyzed. The patients were divided into 3 groups according to the positional relationship between the kyphosis focal on cervical spine X-ray film and the spinal cord compression point on MRI: the same group (group A, 20 cases, both points were in the same position), the adjacent group (group B, 10 cases, both points were located adjacent to each other), and the separated group (group C, 6 cases, both points were located >1 vertebra away from each other). There was no significant difference between groups ( P>0.05) in baseline data such as gender, age, body mass index, lesion segment, disease duration, and preoperative C 2-7 angle, C 2-7 sagittal vertical axis (C 2-7 SVA), C 7 slope (C 7S), kyphotic Cobb angle, fusion segment height, and Japanese Orthopedic Association (JOA) score. The patients underwent single-segment anterior cervical discectomy with fusion (ACDF). The occurrence of postoperative complications was recorded; preoperatively and at last follow-up, the patients' neurological function was evaluated using the JOA score, and the sagittal parameters (C 2-7 angle, C 2-7 SVA, C 7S, kyphotic Cobb angle, and height of the fused segments) were measured on cervical spine X-ray films and MRI and the correction rate of the cervical kyphosis was calculated; the correlation between changes in cervical sagittal parameters before and after operation and the JOA score improvement rate was analyzed using Pearson correlation analysis.
Results: In 36 patients, only 1 case of dysphagia occurred in group A, and the dysphagia symptoms disappeared at 3 days after operation, and the remaining patients had no surgery-related complications during the hospitalization. All patients were followed up 12-42 months, with a mean of 20.1 months; the difference in follow-up time between the groups was not significant ( P>0.05). At last follow-up, all the imaging indicators and JOA scores of patients in the 3 groups were significantly improved when compared with preoperative ones ( P<0.05). The correction rate of cervical kyphosis in group A was significantly better than that in group C, and the improvement rate of JOA score was significantly better than that in groups B and C, all showing significant differences ( P<0.05), and there was no significant difference between the other groups ( P>0.05). The correlation analysis showed that the improvement rate of JOA score was negatively correlated with C 2-7 angle and kyphotic Cobb angle at last follow-up ( r=-0.424, P=0.010; r=-0.573, P<0.001), and positively correlated with the C 7S and correction rate of cervical kyphosis at last follow-up ( r=0.336, P=0.045; r=0.587, P<0.001), and no correlation with the remaining indicators ( P>0.05).
Conclusion: There are three main positional relationships between the cervical kyphosis focal and the spinal cord compression point on imaging, and they have different impacts on the effectiveness and sagittal parameters after ACDF, and those with the same position cervical kyphosis focal and spinal cord compression point have the best improvement in effectiveness and sagittal parameters.
目的: 探讨伴颈椎后凸畸形的脊髓型颈椎病（cervical spondylotic myelopathy，CSM）颈椎后凸与脊髓受压的影像学特征及对手术疗效的影响。.
方法: 回顾分析2020年1月—2022年12月收治且符合选择标准的36例单节段CSM伴颈椎后凸畸形患者临床资料。根据颈椎X线片后凸顶点与颈椎MRI脊髓压迫点的位置关系分为3组：相同组（A组，20例，两点处于相同位置）、相邻组（B组，10例，两点位置相邻）、相隔组（C组，6例，两点位置相隔>1个椎体）。3组患者性别、年龄、身体质量指数、病变节段、病程及术前C 2～7角、C 2～7矢状位轴向距离（C 2-7 sagittal vertical axis，C 2-7 SVA）、C 7倾斜角（C 7 slope，C 7S）、后凸Cobb角、融合节段高度、日本骨科协会（JOA）评分等基线资料比较差异均无统计学意义（ P>0.05）。患者均行单节段颈前路椎间盘切除融合术（anterior cervical discectomy with fusion，ACDF）。记录患者术后并发症发生情况；术前及末次随访时，采用JOA评分评价患者神经功能，并于颈椎X线片和MRI上测量矢状位参数（C 2～7角、C 2-7 SVA、C 7S、后凸Cobb角、融合节段高度），并计算后凸矫正率；采用Pearson相关分析手术前后颈椎矢状位参数变化与JOA评分改善率的相关性。.
结果: 36例患者中，仅A组发生1例吞咽困难，术后3 d吞咽困难症状消失，余患者未发生手术相关并发症。所有患者均获随访，随访时间12～42个月，平均20.1个月；3组随访时间比较差异无统计学意义（ P>0.05）。末次随访时3组患者各影像学指标及JOA评分均较术前显著改善（ P<0.05）；A组后凸矫正率显著优于C组，JOA评分改善率显著优于B、C组，差异均有统计学意义（ P<0.05），其余组间比较差异无统计学意义（ P>0.05）。相关性分析示，JOA评分改善率与末次随访时C 2～7角、后凸Cobb角成负相关（ r=−0.424， P=0.010； r=−0.573， P<0.001），与末次随访时C 7S及后凸矫正率成正相关（ r=0.336， P=0.045； r=0.587， P<0.001），与其余指标无相关性（ P>0.05）。.
结论: 颈椎后凸顶点与脊髓压迫点在影像学上主要存在3种位置关系，并对ACDF术后临床效果和矢状位参数产生影响，颈椎后凸顶点与脊髓压迫点相同者临床疗效和矢状位参数改善最佳。.
Keywords: Cervical spondylotic myelopathy; cervical kyphosis; imaging characteristic; sagittal parameter.