Bone resorption marker RANKL in the diagnosis and treatment of patients with maxillary sinus cysts

Background. RANKL (Receptor Activator of Nuclear Factor Kappa-B Ligand) is a protein belonging to the tumor necrosis factor superfamily serving as a specific marker for osteoclast activation and osteolysis. Aim. To determine RANKL levels in the homogenates of Maxillary Sinus Cysts (MSC) at the time of their removal, investigate the correlation of these indicators with the presence of pathology in the upper row of projection teeth in the respective patients, and refine the timing for potential dental implantation or sinus lifting after sinusotomy based on these findings. Materials & Methods. The study included 25 patients aged 20–65 years who underwent surgical treatment for MSCs located on the inferior wall of the sinus. The research methods comprised general clinical, otorhinolaryngological, radiological, and pathohistological techniques and Enzyme-Linked ImmunoSorbent Assay (ELISA) for RANKL in the tissues of the removed cysts. Pathohistological examination revealed retention cysts in 11 patients and pseudocysts in 14 patients. The presence of dental pathology and active odontogenic processes at the time of cyst removal was established based on prospective clinical and radiological evaluations. The dynamics of mucoperiosteal defect regeneration in the MSC, considering RANKL levels, were assessed 3–6 months post-surgery. Results. In the postoperative period, 8 (32%) out of 25 patients exhibited odontogenic alteration processes in the tissues of the maxilla adjacent to the cysts. The RANKL concentration in these patients was [80.65±34.22] pg/µg of protein, while in the other 17 patients without signs of bone damage, it was [33.10±4.35] pg/µg of protein (p<0.05). The threshold RANKL concentration distinguishing these groups in this study was 51.50 pg/µg of protein. Conclusions. In patients with peri-apical bone changes in the maxilla in the projection area of the cysts (alveolar recess), the RANKL level in their homogenates is higher compared to patients without such pathology. Measuring RANKL levels in the homogenates of cysts removed during endonasal maxillary sinusotomy can serve as an additional indicator for planning postoperative dental treatment in these patients. Keywords: ENT-pathology, endoscopic rhinosurgery, histology, postoperative period, paranasal sinus x-ray, treatment.