The Macroscopic and Microscopic Effects of Radiofrequency Injury in the Porcine Tongue

OBJECTIVE: Current treatment protocols for obstructive sleep apnea/hypopnea syndrome with radiofrequency ablation of the base of the tongue are empiric. Injecting local anesthetics and saline into the treatment site is believed to shorten treatment duration and improve results. Our objective is to compare lesions at different energy levels, both macroscopically and histologically, and to determine if electrolyte solution injection results in a larger lesion.

STUDY DESIGN: A prospective, experimental animal study.

SETTING: University-affiliated institution.

SUBJECTS AND METHODS: Five pigs each received four treatments on the right and four on the left side of the tongue. Three of four treatments were applied sequentially by increasing length of exposure (15, 30, or 60 seconds), and the fourth was conducted over 15 seconds after injecting 1 cc of a 1:1 local anesthetic-saline solution into the treatment site. The animals were recovered for three days and then sacrificed. Macroscopic measurements for each lesion were analyzed, and histological comparison was performed.

RESULTS: The average volume of the lesions was 57.36, 65.18, and 60.50 mm³ for treatment durations of 60, 30, and 15 seconds, respectively, and there was no significant difference. Lesion volume at sites where anesthetic-saline was injected had a mean volume of 36.72 mm³. Paired comparison against the three treatment durations revealed significantly smaller lesion volume size (P = 0.0041, 0.0007, 0.0047, respectively).

CONCLUSION: The lesions created with radiofrequency energy were consistent and predictable. The volumes of the lesions did not differ significantly with regard to different energy levels. The lesion was significantly smaller after injection of anestheticsaline at the treatment site.