ИСТИНА

Introduction. Trigeminal neuralgia (TN) may be caused by tumor of the posterior cranial fossa. Among other CPA tumors, meningiomas are one of the most common to provoke TN. Materials and methods. 50 patients were operated because of posterior fossa meningioma with associated TN in the Burdenko Neurosurgical Institute from 2012 to 2017. 4 types of tumor’s location were selected: petroclival meningiomas (19 patients – 38%), petrous apex meningiomas (16 patients – 32%), posterior surface of petrous bone’s meningiomas (12 patients = 24%) and multiple meningiomas of posterior fossa (3 patients – 6%). 29 patients (58%) had a left-sided lesion, 21 patient (42%) – right sided lesion. 3 types of conflicts were found out intraoperatively. Trigeminal nerve was affected in the root entry zone by the tumor in 35 (70%) cases, by the dislocated artery in 11 (22%) cases. In 4 (8%) cases trigeminal nerve was dislocated by the tumor and affected by artery. All patients underwent surgical removing of the tumor. Vascular decompression was performed in 30% of cases. Results: According to the BNIPS classification 21 patient (72%) have a full pain-free recovery after operation (BNIPS-1). 6 patients (21%) have a rare episodes of low intensive pain attacks which do not require medication (BNIPS-2). 1 patient (3%) has trigeminal neuralgia which is well-controlled by medication (BNIPS-3). And 1 (3%) patient has trigeminal neuralgia without good medicated pain control (BNIPS-4). Surgical complications included: cerebrospinal rhinorrhea – 2 patients (4%) and brainstem edema that required posterior fossa decompression – 1 patient (2%). 13 patients had a hypoesthesia of the face on the side of lesion after surgery. Mild facial paresis (HB scale 1-3) occurred in 4 patients (8%), severe– in 5 patients (10%) (HB scale 4-6). Hearing loss on the side of the lesion was found in 7 patients after surgery, impaired – 1 patient (2%). 3 patients had a caudal CN disturbances (6%) and 4 patients had a cerebellar symptoms after operation. Conclusions: TN may be caused by the tumor’s compression of trigeminal nerve near to REZ. It also can be the result of complex compression maiden by tumor and vessel. Depending on the type of compression vascular decompression of trigeminal nerve should be added to neurosurgical intervention. Key words: skull base meningioma, petroclival meningioma, trigeminal neuralgia.