Frontal ostium neo-osteogenesis and restenosis after modified endoscopic Lothrop procedure in an animal model.

All patients who undergo a modified endoscopic Lothrop procedure have postoperative narrowing of the enlarged frontal ostium. The aim of this study is to evaluate neo-osteogenesis and restenosis of the frontal ostium and its effect on mucociliary clearance. Fourteen sheep underwent an endoscopic modified Lothrop procedure. Pre- and postoperative nuclear medicine gamma scintigraphy of the frontal sinuses was performed. The sizes of the frontal ostia were measured and biopsies taken from the bone of the frontal ostium. Histological evidence of new bone formation was found in 56% of biopsies. The average preoperative mucociliary clearance half times (T1/2) at 15 and 30 min were 70 and 74 min, respectively, and postoperatively were 50 and 67 min. There was a non-significant trend towards poorer clearance in sinuses with neo-osteogenesis. The average size of the frontal ostium decreased by 28%. There was no relationship between the size of the ostium and neo-osteogenesis. Neo-osteogenesis was seen in 56% of biopsies with a 28% reduction in size of the frontal ostium after 224 days. Mucociliary clearance did not alter significantly.

The effect of the modified endoscopic Lothrop procedure on the mucociliary clearance of the frontal sinus in an animal model.

BACKGROUND: The surgical management of recalcitrant frontal sinus disease has been a dilemma for otolaryngologists for many years. Although the osteoplastic flap with obliteration has been the gold standard of treatment for years, the modified endoscopic Lothrop (MEL) procedure recently has been advocated as an alternative. However, little is known about the effect of this procedure on the mucociliary drainage of the frontal sinuses postoperatively and this animal study addresses this issue. METHODS: Fourteen sheep underwent the MEL procedure. The sheep were randomized regarding the use of postoperative irrigation via minitrephines. Each sheep had a nuclear medicine gamma-scintigraphy frontal sinus clearance study via minitrephines performed on each frontal sinus preoperatively and then 3 months postoperatively. Then, the results of these studies were compared. RESULTS: The scans revealed a trend toward faster clearance times postoperatively. However, this decrease was not statistically significant. Importantly, there was no trend or significant increase in clearance times postoperatively. Also, the use of postoperative irrigation was associated with a nonsignificant trend toward faster clearance times postoperatively. CONCLUSION: The MEL procedure has no adverse effects on the mucociliary clearance of the frontal sinus at 3 months postoperatively. Irrigation of the frontal sinus in the immediate postoperative period showed a trend toward improved postoperative mucociliary function at 3 months.