Objective: To compare the predictive abilities of O-C2 angle (O-C2a), O-EA angle (O-EAa), and Oc-Ax angle (Oc-Axa) for development of dysphagia in patients after occipitocervical fusion (OCF).
Methods: Between April 2010 and May 2019, 114 patients who underwent OCF and met the selection criteria were selected as the research objects. Among them, 54 were males and 60 were females; they were 14-76 years old, with an average of 50.6 years old. The follow-up time was 13-122 months (median, 60.5 months). The O-C2a, O-EAa, Oc-Axa, and the narrowest oropharyngeal airway space (nPAS) were measured by the lateral X-ray films before operation and at last follow-up, and the differences before and after operation (dO-C2a, dO-EAa, dOc-Axa, and dnPAS) were calculated. Patients were divided into two groups according to whether they had developed postoperative dysphagia. The general data including age, gender, fixed segment, proportion of patients with rheumatoid arthritis (RA), atlantoaxial subluxation (AS), and combined with anterior release surgery (ARS), and imaging indicators were compared between the two groups. The correlations between dO-C2a, dO-EAa, and dOc-Axa and dnPAS in 114 patients were analyzed to further compare the predictive value of three imaging indicators for occurrence of dysphagia after OCF.
Results: Dysphagia occurred after OCF in 31 cases with the incidence of 27.2%. There was significant difference in gender between the dysphagia group and the non-dysphagia group ( χ 2=7.940, P=0.005). There was no significant difference between the two groups in age, fixed segment, the proportion of patients with RA, the proportion of patients with AS, and the proportion of patients combined with ARS ( P>0.05). There was no significant difference in O-C2a and Oc-Axa of 114 patients before operation and at last follow-up ( P>0.05). The differences in O-EAa and nPAS were significant ( P<0.05). There was no significant difference in preoperative O-EAa, Oc-Axa, and nPAS between the dysphagia group and the non-dysphagia group ( P>0.05); the difference in the O-C2a was significant ( t=2.470, P=0.016). At last follow-up, the differences in the above imaging indicators were significant ( P<0.05). There were significant differences in the dO-C2a, dO-EAa, dOc-Axa, and dnPAS between the two groups ( P<0.05). Correlation analysis showed that the dO-C2a, dO-EAa, dOc-Axa were all positively correlated with dnPAS ( P<0.05). The dO-C2a≤-5°, postoperative O-EAa≤100°, postoperative Oc-Axa≤65° were all related to postoperative dysphagia ( P<0.05), and the highest risk factor suffering postoperative dysphagia was dO-C2a ≤-5° with a significant OR of 14.4.
Conclusion: The dO-C2a, postoperative O-EAa, and postoperative Oc-Axa can be used as the predictive indexes of dysphagia after OCF, among which dO-C2a has the highest predictive value.
目的: 探讨 O-C2 角、O-EA 角及 Oc-Ax 角对于枕颈融合术后患者发生吞咽困难的预测作用。.
方法: 以 2010 年 4 月—2019 年 5 月 114 例行枕颈融合术且符合选择标准的患者作为研究对象。其中男 54 例，女 60 例；年龄 14～76 岁，平均 50.6 岁。术后随访时间 13～122 个月，中位时间 60.5 个月。收集患者术前以及末次随访时颈椎侧位 X 线片，测量 O-C2 角、O-EA 角、Oc-Ax 角和 nPAS，并计算手术前后差值（dO-C2 角、dO-EA 角、dOc-Ax 角和 dnPAS）。根据术后是否出现吞咽困难，将患者分为吞咽困难组和无吞咽困难组。比较两组患者一般资料（年龄、性别、固定节段以及合并类风湿性关节炎、寰枢椎脱位及联合前路减压术患者比例）、影像学指标，分析 114 例患者 dO-C2 角、dO-EA 角、dOc-Ax 角与 dnPAS 相关性，比较 3 种影像学指标对枕颈融合术后吞咽困难发生的预测价值。.
结果: 术后 31 例发生吞咽困难，发生率为 27.2%。吞咽困难组和无吞咽困难组患者年龄、固定节段以及合并类风湿性关节炎、寰枢椎脱位及联合前路减压术患者比例比较，差异均无统计学意义（ P>0.05）；性别比较差异有统计学意义（ χ 2=7.940， P=0.005）。114 例患者术前与末次随访时 O-C2 角和 Oc-Ax 角比较，差异无统计学意义（ P>0.05）；O-EA 角和 nPAS 比较，差异有统计学意义（ P<0.05）。吞咽困难组和无吞咽困难组患者术前 O-EA 角、Oc-Ax 角、nPAS 比较差异均无统计学意义（ P>0.05），O-C2 角比较差异有统计学意义（ t=2.470， P=0.016）；末次随访时上述指标比较差异均有统计学意义（ P<0.05）。两组患者 dO-EA 角、dOc-Ax 角、dO-C2 角、dnPAS 比较，差异均有统计学意义（ P<0.05）。相关性分析显示，dO-C2 角、dO-EA 角、dOc-Ax 角均与 dnPAS 成正相关（ P<0.05）。dO-C2 角≤−5°、术后 O-EA 角≤100°、术后 Oc-Ax 角≤65° 时均存在术后吞咽困难发生风险（ P<0.05），其中 dO-C2 角≤−5° 时发生风险最大（ OR=14.4）。.
结论: dO-C2 角、术后 O-EA 角、术后 Oc-Ax 角均可作为枕颈融合术后吞咽困难的预测指标，其中 dO-C2 角预测价值最大。.
Keywords: O-C2 angle; O-EA angle; Oc-Ax angle; Occipitocervical fusion; complication; dysphagia; nPAS; occipitocervical angle.