Effect of intratonsillar injection of steroids on the palatine tonsils of rabbits.

Objectives/Hypothesis Nasal steroids may significantly improve nasal obstructive symptoms with a reduction of adenoid size in children, but they do not consistently yield the same concurrent effect on enlarged palatine tonsils. Failure of nasal steroids to decrease the size of palatine tonsils is believed to be attributable to location and washout by saliva. The purpose of this study was to determine if direct application of steroid via intratonsillar injection would reduce the size of palatine tonsils in the rabbit model. Study Design Prospective animal study. Methods Eight rabbits (16 tonsils) were administered intratonsillar injections of fluticasone (n = 8, 1 mg/ml) or saline (n = 8, 0.1 ml) on days 0, 3, 7, 10, 14, and 17. Two rabbits (4 tonsils) received a single steroid injection to compare single versus multiple steroid injections. The rabbit's tonsil size was measured before each injection. After the fifty injections, the tonsils were harvested for histologic analysis. Results A total of 16 tonsils were analyzed. After five steroid injections, the reduction (−7.7 mm2 ± 4.27) in size was statistically significant when compared to reduction (6.12 mm2 ± 6.57) in the saline injected group (P = 0.001). Repeated steroid injection was more potent than a single injection (−3.00 mm2 ± 3.08) in reducing the size (P = 0.006). In histologic analysis, tonsils after repeated steroid injections were significantly smaller than saline-injected tonsils (P = 0.014), without obvious lymphoid follicles. Conclusion Repeated focal tonsillar injections of corticosteroids significantly reduced the size of palatine tonsils as compared to saline-injected controls. A single injection of corticosteroids appears to be effective, but not as effective, as multiple injections. Level of Evidence N/A. Laryngoscope, 124:2811–2817, 2013