ObjectiveTo introduce a new occipitocervical angle parameter, occipito-odontoid angle (O-Da), for predicting dysphagia after occipitocervical fusion (OCF) in patients with C2, 3 Klippel-Feil syndrome (KFS) and analyze its effectiveness. Methods A total of 119 patients met selective criteria between April 2010 and November 2019 were retrospectively included as the study subjects. There were 56 males and 63 females. The age ranged from 14 to 76 years, with a median age of 51 years. There were 44 cases of basilar invagination and 75 cases of atlantoaxial subluxation. Forty patients were combined with C2, 3 KFS. Seven patients underwent anterior decompression combined with posterior OCF and 112 patients underwent posterior OCF. The fixed segments were O-C2 in 36 cases, O-C3 in 51 cases, O-C4 in 25 cases, and O-C5 in 7 cases. All patients were followed up 21-136 months, with a median time of 79 months. The lateral cervical X-ray films before operation and at last follow-up were used to measure the occipital to C2 angle (O-C2a), the occipital and external acoustic meatus to axis angle (O-EAa), the occipital protuberance to axial angle (Oc-Axa), the O-Da, and the narrowest oropharyngeal airway space (nPAS). The differences of the above parameters between the last follow-up and the preoperative values were calculated (represented as dO-C2a, dO-EAa, dOc-Axa, dO-Da, and dnPAS). Patients were divided into two groups according to whether they suffered dysphagia after operation, and the differences in clinical data and radiographic parameters were compared between the two groups. The correlation between occipitocervical angle parameters and nPAS in 40 patients with C2, 3 KFS was analyzed respectively. In addition, sensitivity and specificity analyses were used to assess the effectiveness of dO-Da≤−5° for the prediction of postoperative dysphagia. ResultsThirty-one patients (26.1%) suffered dysphagia after OCF (dysphagia group), including 10 patients with C2, 3 KFS; no dysphagia occurred in 88 patients (non-dysphagia group). There was no significant difference in age, follow-up time, fixed segment, proportion of patients with rheumatoid arthritis, proportion of patients with atlantoaxial subluxation, and proportion of patients with C2, 3 KFS between the two groups (P>0.05). The proportion of female patients was significantly higher in dysphagia group than in non-dysphagia group (χ2=7.600, P=0.006). The difference in preoperative O-C2a between the two groups was significant (t=2.528, P=0.014). No significant differences were observed in preoperative O-EAa, Oc-Axa, O-Da, and nPAS (P>0.05). There was no significant difference in dO-C2a, dO-EAa, dOc-Axa, dO-Da, and dnPAS between the two groups (P>0.05). The dO-C2a, dO-EAa, dOc-Axa, and dO-Da were positively correlated with dnPAS in 40 patients with C2, 3 KFS (r=0.604, P<0.001; r=0.649, P<0.001; r=0.615, P<0.001; r=0.672, P<0.001). Taking dO-Da≤−5° as the standard, the sensitivity and specificity of dO-Da to predict postoperative dysphagia in patients with C2, 3 KFS were 80.0% (8/10) and 93.3% (28/30), respectively. ConclusionThe dO-Da is a reliable indicator for predicting dysphagia after OCF in patients with C2, 3 KFS.
ObjectiveTo 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).MethodsBetween 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.ResultsDysphagia 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 (χ2=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.ConclusionThe 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.