Incidence and severity of dysphagia after anterior cervical discectomy and fusion with zero-profile spacer: prospective study with 3-years follow-up.

Introduction: Dysphagia after anterior cervical discectomy and fusion (ACDF) is a regular complication. The aim of this study was to identify risk factors for incidence and severity of dysphagia after ACDF with zero-profile spacer.
Methods: Incidence and severity of dysphagia was evaluated preoperatively and for time of three years after ACDF (regular outpatient check-ups) ‒ prospective study with 3-years follow-up. Severity of dysphagia was assessed subjectively using Bazaz‒Yoo dysphagia score. Influence of selected factors on the incidence and severity of postoperative dysphagia was evaluated. Following statistical methods were used: Fisher's exact test, unpaired Student's t-test, one-way ANOVA and Spearman's correlation coefficient. Level of significance was defined as p ˂ 0.05. Correlations between paired parameters were evaluated according to Spearman's correlation.
Results: Our study included 133 patients who underwent one-, two- or three-level ACDF with zero-profile spacer in years 2013‒2018. Myelopathy and GERD had significant impact on incidence and severity of pre-existing dysphagia. Risk factors for incidence of dysphagia after ACDF were number of treated segments, myelopathy, pre-existing dysphagia and surgery of C4/5 segment. Age of patients, duration of surgery and pre-existing dysphagia correlated positively very weakly to weakly with severity of dysphagia after ACDF. Number of treated segments, myelopathy, GERD and surgery of the C4/5 segment were risk factors for greater severity of postoperative dysphagia.
Conclusion: Risk factors for incidence and severity of pre-existing dysphagia were myelopathy and GERD. Risk factors for dysphagia incidence after ACDF were number of treated segments, pre-existing dysphagia, myelopathy and surgery of C4/5 segment (Tab. 6, Fig. 1, Ref. 30).