JYRI MYLLER Middle Meatal Antrostomy in Endoscopic Sinus Surgery

Background: Chronic rhinosinusitis (CRS) is an inflammation of the nose and paranasal sinuses lasting more than 12 weeks. It is diagnosed by typical symptoms and/or a computed tomography (CT) scan and/or endoscopic changes. In a recent study the prevalence of CRS in the European population was found to be 10.9%. After failure of maximal conservative therapy, endoscopic sinus surgery (ESS) aims to restore normal sinus function and ventilation through the natural ostia. Traditionally, in maxillary sinus surgery, ESS was initiated with the removal of the uncinate process combined with middle meatal antrostomy. Anterior ethmoidal cells were also often opened. The minimally invasive technique of maxillary sinus surgery concentrates only on the uncinate process. Since the introduction of this technique, there have been controversial opinions on the advantages of simple uncinectomy over maxillary sinus antrostomy. Subjects and methods: The study group comprised 30 patients (20 women and 10 men) aged between 22 and 66 years, with a mean age of 47 years. They all suffered from chronic maxillary rhinosinusitis with associated mucosal thickening or sinus opacification in the CT scan. There was no difference in the symptoms between each side of the nose, and the preoperative CT scans showed identical moderate findings on both sides. A nasal endoscopy was performed to exclude patients with visible polyposis from the study. The study group underwent ESS under local anaesthesia. Uncinectomy alone was performed on one side. In addition, a middle meatal antrostomy was performed on the contralateral side to duplicate the size of the natural ostium. Ethmoidal bulla was resected bilaterally in 25 patients. Part of the patients in the study group received conservative therapy (intranasal corticosteroid and/or oral antihistamine) both preand postoperatively. Nasal endoscopy, a CT scan and measurements of mucociliary clearance (MCC) were performed preoperatively and nine months postoperatively. Maxillary sinus mucosa biopsy specimens were taken for histopathological and immunohistochemical evaluations intraoperatively and 9 months postoperatively from this study group. Patient questionnaires were completed at 1 month preoperatively, and at 1, 3, 9 and 68 months postoperatively. Maxillary sinus specimens were also obtained from an additional subject group that consisted of healthy controls and CRS patients with or without nasal polyposis. Results: We were able to demonstrate that the percentage of vessels expressing endothelial sulphated sialyl-LewisX epitopes (L-selectin ligands) in maxillary sinus biopsies taken intraoperatively increased during CRS compared with uninflamed control tissue. In addition, the expression level of these epitopes and the number of mucosal eosinophils correlated with the inflammation, and they decreased nine months postoperatively compared with intraoperative samples, especially in patients with intranasal corticosteroid treatment. The postoperative reduction of these L-selectin ligands was independent of the operation technique. There was a statistically significant correlation between the postoperative number of mucosal eosinophils and the symptom score, which was also independent of the surgical technique. A statistically significant postoperative decrease of mucosal eosinophils, as well as the correlation of the intraoperative eosinophils with the postoperative symptom score, was found only on the antrostomy side. Surgery did not significantly improve the mucociliary function of the maxillary sinus mucosa; it remained poor even nine months postoperatively. There was no statistical difference between the operative techniques. Comparison of the preoperative and postoperative CT scans revealed that a significant reduction in the radiological Lund-Mackay (LM) score was achieved on both sides, regardless of the procedure performed. The postoperative area of the ostium remained significantly larger on the antrostomy side compared with the uncinectomy side. Comparison of long-term subjective outcomes revealed a significant reduction of symptoms on both sides. There were no significant differences between the uncinectomy with additional antrostomy and the uncinectomy-only sides in terms of satisfaction with the operation, facial pain, nasal obstruction, or discharge values. Additional middle meatal antrostomy seemed to be slightly superior in terms of the need for revision operations. However, this difference was statistically insignificant. The number of prescribed antibiotic courses for acute exacerbations began to increase between the nineand, on average, 68-month period postoperatively. It seemed that patients with asthma and/or job exposure to irritants might experience less satisfaction with the uncinectomy-only side, whereas patients without these risk factors experienced similar satisfaction after both procedures. This observation did not however reach statistical difference. Conclusion: Endoscopic sinus surgery (ESS) has a positive impact on subjective outcomes, radiological Lund-Mackay scores, sinus mucosa L-selectin ligands and eosinophils regardless of the type of the operation performed. Mucociliary clearance remains poor even after nine months of ESS, indicating poor recovery of the ciliary function. There were no statistically significant differences between the types of operation. However, there is a slight tendency for better results with ostium-enlarging surgery.