Influence of anterior cervical plate design on dysphagia - A 2-year prospective longitudinal follow-up study

Objective: To compare the incidence, prevalence, and rate of improvement of dysphagia in patients undergoing anterior cervical spine surgery with two different anterior instrumentation designs. Methods: The study subjects were 156 consecutive patients undergoing anterior cervical spine surgery with plate fixation. We compared the incidence of dysphagia among the two different plate groups both produced by the same manufacturer (Medtronic Danek); the Atlantis plate has thicker and wider plate dimensions than the Zephir plate. Dysphagia evaluations were performed prospectively by telephone interviews at 1, 2, 6, 12, and 24 months following the procedure. Risk factors such as gender, revision surgery, and number of surgical levels were compared between the groups and were not statistically different. Results: Overall incidences of dysphagia were 49%, 37%, 20%, 15.4%, and 11% at 1, 2, 6, 12, and 24 months, respectively. Severe and disabling dysphagia is reported to be a relatively uncommon complication of anterior cervical surgery. However, a significant number of patients report mild to moderate discomfort including double-swallowing and catching sensation. Except at the 2-month follow-up point, the Atlantis plate group had higher incidences of dysphagia than the Zephir group at all time points (57% vs 50%, 36% vs 4%, 23% vs 14%, 17% vs 7%, 14% vs 0% at 1, 2, 6, 12, and 24 months, respectively). The Atlantis plate group had a 14% incidence of dysphagia at 2 years compared with the Zephir group, which had a 0% incidence at 2 years (P < 0.04). For primary surgeries, there was a higher incidence of dysphagia at all tithe points in the Atlantis group when compared with the Zephir group (58% vs 43%, 35% vs 30%,22% vs 10%. 17% vs 0%, and 13% vs 0% at 1, 2, 6, 12, and 24 months, respectively) (P < 0.04 at 1 year). A regression analysis was performed. The resulting formulas predict the permanent rate of dysphagia for the Atlantis group is 13.6% and for the Zephir group is 3.58%. Conclusions: The use of a smaller and smoother profile plate such as the Zephir does reduce the incidence of dysphagia as compared with a slightly larger and less smooth plate such as the Atlantis.