ИСТИНА

Most of the current studies about skull base tumours focused on the analysis of the radical operations results especially taking into account the popularity of endoscopic access. In contrast, the studies about the reconstruction operations of the skull base defects after tumour resection are rare. We retrospectively reviewed medical histories of the patients after transnasal endoscopic resection of the skull based tumours with the one-step reconstruction of the defect and developed the defects classification, and practical guidelines for their treatment. Materials and Methods Total of 50 medical histories reviewed. The results of the operation assessed in early and late postoperative periods. Fisher's and Chi-squared tests were used for the analysis of the results. Results compared with previous studies found by the literature search. Result All 50 patients underwent transnasal endoscopic resection of the skull based tumours and one-step reconstruction of the defect. The choice of the technique and materials for defect reconstruction did not depend on the malignancy of the tumour (Chi-squared p=0.174). Histopathological type of the tumour and radiotherapy did not affect the development of the cerebrospinal fluid leakage in the postoperative period (Fisher's test p = 0.221). We developed a classification of skull based defects base on their size, localization and materials used for reconstruction. Conclusion In cases of intracranial tumours (intranasal or sinonasal) the resection is indicated by endoscopic or complex access with one-step skull base defect reconstruction. The choice of plastic materials and reconstruction method depends on defect localization and size, extend of tumour lesion and involvement of dura mater. Reconstruction efficacy does not depend on tumour histopathological type and subsequent chemo- and radiotherapy. Keywords. Skull base, Endoscopic surgery, skull base tumors, skull base defects