Incidence and Predictors of Dysphagia Following Anterior Cervical Discectomy and Fusion: Prospective Observational Study

The incidence of dysphagia following anterior cervical discectomy and fusion (ACDF) reported in the literature varies due to differences in measures and time intervals applied, ranging from nearly 3/4 at 2 weeks to 13% at 12 months. The most commonly used dysphagia scales remain subjective, non-validated, and do not capture functional impact. Various risk factors have been identified, though few consistently reproduced and none studied in an Australasian context. The aims of this study were to use objective and validated measures, assess both traditional and novel risk factors, and determine the impact of dysphagia on dietary status, length of stay and complications. METHODS: Twenty-nine adults undergoing ACDF for degenerative pathologies were enrolled between March and November 2015 in an Australian institution. Bazaz dysphagia scale, Dysphagia short questionnaire, 3-ounce swallow test and dietary status were assessed preoperatively, and 2 days and 6 weeks postoperatively. Descriptive statistics were used to characterise the study sample and logistic regression modelling performed on risk factors. RESULTS: Dysphagia incidence ranged from 85% on day-2 Dysphagia short questionnaire to zero on 6-week 3-ounce swallow. All measures increased at 2 days and fell by 6 weeks. Failing day-2 3-ounce swallow was the only measure associated with modifications in solids (P = 0.06), showing significant linear correlation (P = 0.02). Respiratory comorbidity increased risk of failing day-2 3-ounce swallow by more than 32-fold (OR: 32.4; 95% CI: 1.8 - 587.7; P = 0.019) and scoring moderate or severe on Bazaz by almost 10-times (OR: 9.3; 95% CI: 0.9 - 95.95; P = 0.061). Psychiatric history also increased risk of failing day-2 3-ounce swallow by more than 10-fold (OR: 10.9; 95% CI: 1 - 123.7; P = 0.054). Failing 3-ounce swallow increased length of stay (5 versus 7 days; P = 0.013). CONCLUSIONS: Incidence of dysphagia following ACDF was dependent on the measure used, though all improved over time. The 3-ounce swallow test correlated with dietary modification and length of stay, while respiratory comorbidity posed the most significant risk. This may identify a group of patients who may benefit from early intervention.