Postoperative dysphagia versus neurogenic dysphagia: scintigraphic assessment

In order to differentiate the features of dysphagia that occur after supraglottic horizontal laryngectomy from those that occur during neurologic diseases, we divided 38 subjects into 3 groups and submitted them to oropharyngoesophageal scintigraphy. Group 1 (control group) included 15 healthy volunteeers; group 2 comprised 8 patients who had residual dysphagia at least 1 year after supraglottic laryngectomy; and group 3 included 15 patients with various neurologic and neuromuscular disorders. In group 1, the mean values (+/- 2 SD) of selected semiquantitative parameters were consistent with those reported in the literature for normal subjects. In group 2, oral, pharyngeal, and esophageal transit times were not significantly altered, and moderate tracheobronchial post-deglutitive aspiration was present (maximum value, 6.7%; mean value, 2.04%). The pharyngeal retention index was significantly increased (p = .0003) as compared to normal subjects in all cases (maximum value, 40%; mean value, 23%) and was associated in all cases with slight but consistent post-deglutitive aspiration. In group 3, the oral and esophageal phases were significantly prolonged and the retention indices were significantly increased. Statistical analysis documented a significant increase in oral transit time (p = .003), esophageal transit time (p = .01), oral retention index (p = .006), pharyngeal retention index (p = .0007), and esophageal retention index (p = .009) as compared to normal subjects. The swallowing pattern was also altered by 1) an early loss of the bolus from the oral cavity; 2) bolus fragmentation due to double or triple deglutition, reduced lingual propulsion, or the return of a small part of the bolus into the oral cavity during deglutition; and/or 3) double pharyngeal peaks in the activity-time curves. Tracheobronchial aspiration (maximum value, 90%; mean value, 9.70%) was present in some cases, mainly in patients affected by post-stroke dysphagia. On the basis of the obtained results and considering the low doses of radiation delivered to the patient (0.043 Gy), the limited invasiveness, and the excellent patient tolerance, scintigraphy appears to be clinically valid in the functional study of swallowing and in identifying different deglutition disorders.