Is the likelihood of dysphagia different in patients undergoing one-level versus two-level anterior cervical discectomy and fusion?

Background Context: Dysphagia following anterior cervical discectomy and fusion (ACDF) is a common complication, the etiology of which has not been established. Given that one potential mechanism for dysphagia is local tissue edema, it is thought that a greater number of operative levels may result in higher dysphagia rates. However, prior reports comparing one-level to two-level ACDF have shown varying results.
Purpose: To determine if there is a difference in dysphagia between one-level and two-level ACDF.
Study Design/setting: Retrospective review of prospectively collected data.
Patient Sample: Patients who underwent one- or two-level ACDF with a plate-graft construct by a single-surgeon at a high-volume academic medical center.
Outcome Measures: Neck Disability Index, Visual Analog Scale for neck pain and arm pain, Short Form-12 physical and mental health components, and Swallowing Quality of Life (SWAL-QOL) Questionnaire.
Methods: Patient demographics, operative data, and patient-reported outcome measures (PROMs; Neck Disability Index, Visual Analog Scale, Short Form-12, and SWAL-QOL) of patients undergoing one- and two-level ACDF were compared using Fisher exact test for categorical variables and Student's t test for continuous variables. Regression analyses were conducted to identify factors associated with 6- and 12-week SWAL-QOL scores in order to determine whether the number of surgical levels impacts these outcomes.
Results: Fifty-eight patients (22 one-level and 36 two-level ACDF) were included. Patients undergoing two-level fusions were older (54.17+8.67 vs 48.06+10.68 years, p=.02) and had longer operative times (69.08+10.51 vs 53.5+14.35 minutes, p<.0001). There were no other significant differences in demographics or operative data. Both groups showed a statistically significant improvement in PROMs from preoperatively to 12 weeks. There was no difference in PROMs or dysphagia rates between groups at any time-point. Younger age (p=.023), male sex (p=.021), longer operative times (p=.068), and worse preoperative SWAL-QOL (p<.0001) were associated with dysphagia at 6 weeks. Preoperative SWAL-QOL was the only variable associated with dysphagia at 12 weeks (p=.003). Operative time of >61.5 minutes had a sensitivity and specificity of 62.1% for worse dysphagia scores at 6 weeks compared with baseline.
Conclusions: The results of our study indicate that there is no difference in the degree of postoperative dysphagia in one- versus two-level ACDF. However, other variables associated with increased postoperative dysphagia in our population included younger age, male sex, procedural time >61.5 minutes, and worse preoperative dysphagia. Larger studies are required to confirm these findings and identify additional risk factors for postoperative dysphagia.
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