Reduction in hyoid bone forward movement in irradiated nasopharyngeal carcinoma patients with dysphagia

Objective: To quantitatively assess the movement of the hyoid bone and pyriform sinus stasis in irradiated nasopharyngeal carcinoma (NPC) patients suffering from dysphagia.

Design: Retrospective data analysis.

Setting: A tertiary teaching hospital.

Participants: NPC subjects (n=33, 25 men and 8 women) and healthy subjects (n=10, 7 men and 3 women) participated in the study.

Intervention: Videofluoroscopic swallowing study (VFSS) of all subjects.

Main outcome measures: The displacement and velocity of hyoid bone movement, the amount of pyriform sinus stasis, and the widest opening distance of the cricopharyngeal muscle during swallowing.

Results: The displacement of the hyoid bone in the NPC patients was significantly less than that of the healthy subjects (1.58+/-0.59 vs 2.23+/-0.49 cm, P=.0033). The displacement of the hyoid bone was divided into forward and vertical directions, and the forward displacement in the NPC patients was found to be less than that of the healthy subjects (0.85+/-0.50 vs 1.65+/-0.51 cm), achieving statistic significance (P<.0001). The pyriform sinus stasis of the NPC subjects was significantly more than that of the healthy subjects (2.24+/-0.98 vs 0.30+/-0.17 cm(2), P<.0001). The movement velocity of the NPC subjects was less than that of the healthy subjects (2.49+/-1.41 vs 5.10+/-0.85 cm/s, P=.0086). Furthermore, the NPC subjects with aspiration experienced less displacement of the hyoid bone than those without aspiration (1.23+/-0.45 vs 1.76+/-0.58 cm, P=.029).

Conclusion: The irradiated NPC subjects with dysphagia experienced a reduction in hyoid bone displacement, occurring in a forward direction. The displacement of the hyoid bone was less in the aspiration subjects than in those without aspiration.