Introduction. Today the role of viral contamination of brain tumors and possibility of antiviral therapy are studied widely. Materials and methods. Polymerase chain reaction was used to study the presence of oncoand herpes viruses in medulloblastomas and gliomas of the brain. Results. At research of 61 tumor samples contamination by different viruses was revealed in 47.5% cases, most often — in medulloblastomas (in 51%), less often — in glioblastomas (in 22%). More often virus of herpes VII type (in 16.3%) and polyomaviruses (in 10 %) were found. The shortest period before disease recurrence was observed in patients with medulloblastoma at contamination by polyomavirus SV-40. Conclusions. The role of viruses in oncogenesis initiation, their prognostic value and possibilities to use antiviral therapy for brain tumors treatment need further research.

Syndromes of neurovascular compression or hyperactive disorder (SHD) of cranial nerves at most patients are provocated by vascular compression of corresponding nerve’s root. But some authors deny vascular compression to be the main etiological factor of SHD of cranial nerves and reveal plural contacts of vessels with nerves without those syndromes development. On the base of intraoperative investigation of neuro-vascular relationships it was found out that in the zone of real vascular compression nerve’s root decolouration was observed that meant capillary perfusion infringement and disappeared after decompression; as closer to 90° the pulsation vector according to nerve’s root in the place of contact than probability of SHD occurrence is higher and symptoms of corresponding syndrome are more expressed.

The microanatomy and topography features of intramedullar cranio-spinal tumours were studied. Various microanatomy and topography variants of intramedullar cranio-spinal tumours were given.The necessity to emanate from various types of intramedullar cranio-spinal tumors localization and their interactions with neurovascular structures in this area was proved at treatment and surgical interventions planning, that allowed to decrease considerably postoperative complications.

Microtopographical interrelations of the posterior cranial fossa structures in the presence of cholesteatoma were studied up intraoperatively in 36 cases and while the pathomorphological investigation conduction in 6 sectional observations. Cholesteatoma mostly localizes in cerebellopontile angle and more rarely--in the IV ventricle with craniospinal spreading. It is the tumor's capsule texture what causes dense adherence of cholesteatoma with surrounding cranial nerves, vessels, incorporated frequently in her structure together with underlying cerebral substance.

The microsurgical anatomy peculiarities of a large size tumor of n. vestibulocochlearis (NVC) were studied, basing on intraoperative (in 380 patients) and sectional (30) observations data. The distinguishing of three main anatomic-topographical variants of a large size NVC tumor growth has great significance for elaboration of the microsurgical tumoral excision method.

The postoperative period course and an autopsy data of 68 patients operated on for n. vestibulocochlearis neurinoma, parasternal meningioma, cholesteatoma. Principal damaging factors and cerebral stem functional disorders are assigned.