Background: The anatomic variation of the frontal sinus and frontal recess can create both a diagnostic and therapeutic challenge. Most cases of frontal sinus disease can now be treated by endoscopic approaches. For refractory cases or those with severe pathology, the microscopically controlled drainage (MCD) operation has at times been successful and spared the patient the morbidity of an external approach. The aim of this study was to evaluate microscopically controlled frontal sinus surgery in these difficult cases.
Material and methods: Prospective analysis was performed on the efficacy of MCD in patients for whom endoscopic sinus surgery had failed or in primary cases with severe pathology or unfavorable anatomy. The technique employs a self-retaining endonasal retractor and a diamond bur under microscopic visualization to remove solid bone (frontal spine) obstructing the sinus drainage and allow a wide opening of the frontal recess while causing minimal mucosal damage. Unilateral drainage (extended frontal sinus drainage operation), and in some cases bilateral drainage (median drainage procedure) is employed.
Results: With an average of 23 months of follow-up, over 90% of patients were either free of symptoms or substantially improved after the MCD procedure. Three patients required revision surgery (extend the opening into a median drainage procedure) for adequate relief of symptoms.
Conclusions: The MCD procedure is highly successful in the treatment of frontal recess disease, particularly in those cases of severe pathology or difficult anatomy. It may be used in those cases refractory to standard endoscopic sinus surgery where an external approach and frontal sinus obliteration are contemplated. As with endoscopic sinus surgery, precise knowledge of the frontal recess and neighboring landmarks is critical, and adequate drainage with minimal mucosal disruption should be the goal.