Swallowing Function Defined by Videofluoroscopic Swallowing Studies after Anterior Cervical Discectomy and Fusion: a Prospective Study

This study evaluated factors related to swallowing dysfunction after anterior cervical discectomy and fusion (ACDF) using videofluoroscopic swallowing studies (VFSS). Preoperative and postoperative VFSSs were done with 5 mL diluted barium. Oral transit time, pharyngeal delay time, pharyngeal response time (PRT), and pharyngeal transit time were measured. Hyoid bone movement and upper esophageal sphincter (UES) diameter were measured serially. Thickness of prevertebral soft tissue was measured from digitized VFSS images. In results, 12 of 20 patients showed abnormal postoperative VFSS findings. PRT decreased significantly after surgery. Hyoid bone movement did not change significantly after surgery. The maximal distance of UES opening decreased significantly after surgery, and the higher the level of surgery (C3>C4>C5>C6), the greater the decrease in maximal distance of the UES opening after surgery. The time to widest opening of the UES was prolonged significantly. At the C3 and C4 levels, the change in prevertebral soft tissue thickness of patients with VFSS abnormalities was significantly greater than those without abnormalities. In conclusion, patients after ADCF with their highest surgery level at C3 and C4 showed more abnormal VFSS findings, significantly increased soft tissue thickness, and decreased maximal distance of UES opening. VFSS provided objective data related with swallowing dysfunction after ACDF.