INTRODUCTION: The incidence of dysphagia after anterior cervical surgery has been well documented in the literature. Specifically, recent studies evaluating post‐operative dysphagia in ACDF have shown a correlation with plate thickness anteriorly and development of dysphagia. Studies have yet to compare development of dysphagia with cervical disc replacements, but given the minimal anterior profile of cervical disc prosthesis as compared to the profile of cervical plates (CSLP), one would postulate a lower incidence of postoperative dysphagia with cervical disc replacements. This is a retrospective analysis of the incidence of post‐operative dysphagia in a randomized controlled trial comparing Prodisc‐C and ACDF.
METHODS: Between August 2003 and September 2004, forty‐four patients were randomized to treatment with ACDF using the Synthes CSLP system or cervical disc replacement surgery using the ProDisc‐C® implant. Of the 44 patients, 22 were treated with ACDF using allograft and plating and 22 were treated with cervical disc replacement. Patients were contacted for a phone survey to determine difficulty swallowing. The phone surveyor was blinded to the treatment. Dysphagia was scored based on an established dysphagia grading system in the literature by Yoo , grading as the following: 0=no difficulty, 1=mild difficulty, 2=moderate difficulty, 3=severe difficulty. A Mann‐Whitney U‐test was performed to determine significant differences between groups and dysphagia scores. A Fisher's exact test was performed to determine statistical differences between groups and the number of patients experiencing moderate to severe dysphagia.
Twenty‐one patients were female, 23 patients were male and the average age was 44 (range 23 to 61). The mean post‐operative follow‐up was 15.8 months, (range 7.9 to 20.6 months). All surgical procedures were single level. There were two procedures at C4‐C5, 22 at level C5‐C6, and 20 at level C6‐C7. All ACDF patients were available for the phone survey and two Prodisc‐C patients were unavailable, despite exhaustive attempts to locate them.
RESULTS: The median dysphagia score for both the ACDF group and the ProDisc‐C group was 0. The mean rank for the ACDF group was 24.7 (U=290.5) and the mean rank for the ProDisc‐C group was 17.9 (U=149.5). The ACDF group trended toward higher dysphagia scores than the ProDisc‐C group (p=.013). Three of the 22 ACDF patients experienced moderate to severe dysphagia. None of the 20 ProDisc‐C patients experienced moderate to severe dysphagia,
CONCLUSION: Post‐operative dysphagia is a well‐documented complication after anterior cervical surgery. Anterior cervical plate design and profile thickness have shown to influence the incidence of post‐operative dysphagia. Given the minimal anterior profile of cervical disc replacements, and using an established dysphagia grading system, we retrospectively compared the incidence of dysphagia in ACDF and ProDisc‐C. With the current limitations in this study of small sample size, we concluded that the post‐operative dysphagia score trended toward being higher for the ACDF group. Continuing this study with additional approved subjects is needed to verify this trend.
1. Bazaz et. al. (2002) Spine 27:2431-34.
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