Some risk factors for refractory chronic sinusitis: an immunohistochemical and electron microscopic study.

The goal of the present work was to investigate possible risk factors for the poor response of some cases of chronic sinusitis to endoscopic sinus surgery in spite of the precision of the surgical technique. Eleven adult patients who were scheduled for revision endoscopic sinus surgery underwent a complete allergy workup. At the time of surgery, a tiny biopsy was taken from the maxillary sinus mucosa close to the middle turbinate. The specimens were processed for histochemical and transmission electron microscopic examination. Six patients (55 per cent) proved to be allergic. Their sinus mucosa showed eosinophilic infiltration (6.1 cells/mm(2)), and mast cell degranulation. This proves that allergens can reach the sinus mucosa and have a direct impact on it. Another three patients (27 per cent) were non-allergic but exhibited mucosal eosinophilia (5.0 cells/mm(2)), and two of them showed mast cell degranulation. These patients were diagnosed as having nonallergic rhinosinusitis with eosinophilia (NARSE). The nasal mucosa of the remaining two patients did not reveal any characteristic pathological findings, and no pathologic diagnosis could be established for them. None of the patients showed electron microscopic evidence of purulent inflammatory changes, and the bacterial cultures recovered normal respiratory flora in nine patients (82 per cent). The present research spotlights the importance of allergy and nonallergic eosinophilic infiltration of the mucosa as possible risk factors that may degrade the results of endoscopic sinus procedures and discusses some pertinent pathological and clinical aspects.