Risk factors for dysphagia after anterior cervical spine surgery: a two-year prospective cohort study

Background context: Severe and disabling dysphagia is a relatively uncommon complication of anterior cervical spine surgery. However, the incidence of dysphagia ranges widely (2% to 60%). Furthermore, risk factors that contribute to the development of dysphagia have not been well identified. Purpose: The purpose of this study was to evaluate the prevalence of dysphagia after anterior cervical spine surgery, and to identify any risk factors associated with increased dysphagia. Study design: This study is a prospective cohort study designed to evaluate the prevalence of dysphagia at 1, 2, 6, 12, and 24 months. Patients were prospectively interviewed at 1, 2, 6, 12, and 24 months regarding the presence and subjective severity of dysphagia. Patient sample: Between the period of 1999 and 2002, 348 cervical spine surgeries were performed using the anterior Smith Robinson approach. 310 of these patients were available for 2-year follow-up. Outcomes measure: Using the dysphagia grading system defined by Bazaz et al. (Spine 2002), we prospectively evaluated patients' postoperative dysphagia. Methods: The presence and severity of dysphagia were reported during the telephone interviews performed at 1, 2, 6, 12, and 24 months after the procedure. Proportion analysis (χ-square or a Fisher Exact Test), prevalence ratios, and 95% confidence intervals were used to compare the prevalence of dysphagia with age, gender, type of surgery (eg, discectomy vs. corpectomy, primary vs. revision), use of instrumentation, number and location of surgical levels. Results: The overall prevalences for dysphagia at 1, 2, 6, 12, and 24 months were 54.0%, 33.6%, 18.6%, 15.2%, and 13.6%. The prevalence of dysphagia was found to be significantly higher in women (18.3%) than men (9.9%) 2 years after the surgery. Revision surgery patients (27.7%) also had a significantly higher prevalence of dysphagia than primary surgery (11.3%) patients 2 years after the surgery. Pateints who underwent more than two-level surgery (19.3%) also had significantly higher rates of dysphagia 2 years after their procedures than patients who had two or less levels (9.7%) operated on. Conclusion: Overall the incidence of dysphagia 2 years after anterior cervical spine surgery was 13.6%. Risk factors for long-term dysphagia after anterior cervical spine surgery include gender, revision surgeries, and multilevel surgeries. The use of instrumentation, higher levels, or corpectomy versus discectomy did not significantly increase the prevalence of dysphagia.