Morphology and vibration pattern of the vocal cord after intracordal Teflon injection: long-term results.

BACKGROUND

Intracordal Teflon injection has been the mainstream management for unilateral vocal cord palsy over the past three decades. In recent years, some investigators concerned about its possible adverse effects on the vibration of the injected vocal cords. It is therefore necessary to clarify the clinical significance of these concerns if Teflon injection will stay as a viable treatment.

METHODS

Twenty-one patients with unilateral vocal cord palsy, who had received Teflon injection for more than one year, were evaluated by flexible laryngovideostroboscopy, basic voice function evaluations and the patient self-assessment.

RESULTS

The morphological and vibratory patterns of the post-injection vocal cords were categorized into seven types according to the videostroboscopic findings. Type I and type II cases had relatively normal morphology and vibration (assorted as group I). Type III through type VII cases showed various kinds of morphological and vibratory abnormalities (assorted as group II). Group I and group II were significantly different in the results of basic voice function evaluations and the patient self-assessment. Group I cases who showed relatively normal morphology and vibration had mean values closer to the normal ranges. For all the patients recruited, their voices were quite stable after injection. None with initial improvement of the voice suffered deterioration.

CONCLUSIONS

The results showed that some patients had nearly normal vibration of the vocal cords years after Teflon injection. True (delayed onset, not due to improper injection) and voice-disturbing Teflon granuloma was not seen in the present study. The majority of cases with disturbed vibration were due to either improper location or an improper amount of injected Teflon. The problems were mostly induced by technical difficulties, not by Teflon-related foreign body reaction. Efforts should be made to avoid these technical errors to increase the predictability of the outcome.