ИСТИНА

Abstract: Objectives: To evaluate the techniques of assessment and monitoring of visual function in patients undergoing resection of the tumors in the vicinity of the optic radiation (OR) and visual cortex, using automatic static perimetry and fractional anisotropy. Background: Preservation of vision is an important aspect of maintaining the quality of life in patients undergoing microsurgical resection of tumors in proximity to the visual pathways. This study is focused on the evaluation of the methods for mapping and monitoring of cortical visual evoked potentials (cVEPs) in this group of patients. Methods: The study included 30 patients with tumors of the occipital, parietal and temporal lobes aged from 20 to 67 years (median 45 years). Before and after surgery, patients underwent magnetic resonance imaging and tractography with OR reconstruction and calculation of fractional anisotropy and volumetry. Visual fields were assessed using automatic static perimetry. The mapping and monitoring of the cVEPs was carried out by recording the cVEPs from the cortical 8 contact electrodes. Results: cVEPs mapping was performed in 10 patients, monitoring in 30, and comprehensive assessment of cVEPs in 20. According to the ophthalmological outcome, the patients were divided into the groups with positive (N = 16) and negative (N = 9) outcomes. A separate group consisted of 5 patients with complete homonymous hemianopia before surgery. Aggressive resection was performed in 23 cases (74%). The fractional anisotropy remained within the normal range in 65% of the patients. The displacement and infiltration of the OR, and a decrease in fractional anisotropy are associated with the detection of visual field defects (p = 0.03, p = 0.02, and p = 0.04, respectively). Conclusions: More than half of the patients (61%) after applying visual monitoring techniques had a positive result, this was confirmed by the data of automatic static perimetry and tractography. Keywords: cortical visual evoked potentials