Impact of tongue base and posterior pharyngeal wall biomechanics on pharyngeal clearance in irradiated postsurgical oral and oropharyngeal cancer patients.

BACKGROUND Postsurgical oral and oropharyngeal cancer patients may experience pharyngeal clearance problems after completion of postoperative radiotherapy. METHODS Swallowing was examined in six patients using videofluoroscopy for up to 1 year after surgery. Biomechanical analysis was used to mark movement of the tongue base and posterior pharyngeal wall during swallowing. RESULTS The majority of patients experienced increased problems with pharyngeal clearance at or after their 6 month posthealing evaluation, generally 18 to 22 weeks after completion of radiotherapy. Pharyngeal residue was associated with a disruption in either tongue base or posterior pharyngeal wall movement. CONCLUSIONS Increased fibrosis of the pharyngeal musculature after completion of radiotherapy may have a negative impact on pharyngeal clearance in addition to any pharyngeal clearance problems resulting from surgical resection. Tongue base to posterior pharyngeal wall contact is essential but not sufficient for effective pharyngeal clearance. Sufficient duration of tongue base to posterior pharyngeal wall contact is also needed to provide adequate pharyngeal bolus driving pressure.