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The aim. To analyze the results of surgical treatment of sacral schwannomas with their extension into lower pelvis.Materials and methods. We analyzed the clinical results of surgical treatment of 25 patients with sacral schwannomas, including those with ventral extension and growth into pelvic cavity. All patients were operated at the Clinic of Neurosurgery of the Novosibirsk Research Institute of Traumatology and Orthopedics named after Ya.L. Tsivyan for a 10-year period. The analysis of literature describing prevalence, classification, diagnosis and surgical treatment of sacral tumors and schwannomas in particular was carried out. The features of the course, diagnosis and surgical treatment of sacral schwannomas and accepted surgical methods for their treatment are described.Results. The average follow-up period of the patients in our study was 61.6 ± 2 months. Compared with the initial indicators of patients in the postoperative period (1 year after the surgery), a good clinical result with the regression of symptoms was registered in 17 (68 %) out of 25 patients, and 10 (40 %) of them had a significant regression of neurological disorders. 3 (12 %) operated patients had a deterioration of neurological disorders in the form of aggravation of sensitive disorders; one patient had an aggravation of pelvic organ dysfunction. Radical removal of the tumor was achieved in 24 (96 %) out of 25 cases; subtotal resection was performed in 1 (4 %) patient. The number of relapses and continued growth of tumors in our series was 12 % (3 out of 25 patients). The mortality rate was 0 %. The complications were registered in 3 (12 %) cases and manifested as wound liquorrhea in cases of using posterior approach.Conclusion. The degree of radicality of tumor resection and clinical outcomes is directly related to the selected surgical approach.

Neurofibromatosis type 2 (NF2) is a rare autosomal dominant disease (frequency 1 in 25-90 000) characterized by the formation of tumors of the central nervous system due to a mutation in the NF2 gene on chromosome 22q12. Bilateral vestibular schwannomas are recognized as absolute diagnostic criteria of NF2 and occur in 95% of patients, are accompanied by hearing impairment, manifest at the age of 18-24 years. Skin manifestations can precede vestibular schwannomas for several years and predict the course of the disease: neurofibromas, cafe-au-lait macules, hypopigmented spots, recently described mesh capillary malformations. Despite the benign nature of schwannomas, they can lead to hearing loss, vestibular dysfunction, facial nerve paralysis, gait disorders, pain and convulsions, there is a risk of early death from compression of the brain stem. The probability of progressive hearing loss is partly determined by the type of mutation. We described a clinical case of NF2 in a 21-year-old patient with bilateral vestibular schwannomas without hearing loss, whose skin examination by ENT specialist revealed this disease. The importance of the presented observation is that the doctor should assume neurofibromatosis type 2 in a young patient with bilateral vestibular schwannomas. It is necessary to undertake a further examination of this patient, including: skin examination for the identification of characteristic neurofibromas and cafe-au-lait macules, consultation with an ophthalmologist, neurologist, MRI of the brain and spinal cord with contrast, genetic analysis - for timely initiation of therapy that prevents hearing loss and vestibular disorders.

Preserving the function of the facial nerve is extremely important in surgery for vestibular schwannomas. Two methods of arachnoid dissection are described for resection of vestibular schwannoma via retrosigmoid approach (from the brain stem and internal auditory canal)., Objective: To evaluate the results of arachnoid dissection of the facial nerve from internal auditory canal when resecting the vestibular schwannoma., Material and Methods: We analyzed 61 patients with vestibular schwannomas. Patients were divided into 2 groups depending on surgical technique. We estimated facial nerve function before and after surgery, preoperative dimension of vestibular schwannoma and extent of resection. The influence of various factors on extent of resection and postoperative facial nerve function was studied., Results: Vestibular schwannoma resection from the brain stem was performed in 30 patients, arachnoid dissection - in 31 patients. There was no significant between-group difference. Gross total resection was performed in 78.7% of cases. Both techniques demonstrated similar results regarding extent of resection. Arachnoid dissection showed the advantage regarding facial nerve function immediately after surgery ( p =0.012) and 6 months later ( p <0.001). Normal facial nerve function in 6 months after arachnoid dissection was observed in 80.7% of patients. Preoperative dimension of tumor influenced facial nerve function in addition to technique of resection ( p =0.001)., Conclusion: We identified the factors influencing facial nerve function after resection of vestibular schwannoma. Surgical technique was the most significant factor. These data expand and popularize arachnoid dissection in surgery of vestibular schwannomas.

Currently, there are no standards in surgical treatment of dumbbell-shaped tumors of lumbo-foraminal region., Objective: To evaluate the effectiveness and long-term results of minimally invasive resection of dumbbell-shaped lumbar schwannomas Eden type 2 and 3 combined with transforaminal lumbar interbody fusion and transpedicular stabilization., Material and Methods: A retrospective study included 13 patients (8 men and 5 women) with lumbar dumbbell tumors Eden type 2 and 3 who underwent minimally invasive facetectomy through posterolateral anatomical corridor, microsurgical tumor resection and MI TLIF. We analyzed intraoperative parameters, neurological functions (ASIA scale), clinical characteristics (ODI, SF-36), and complications. Resection quality and area of the multifidus muscle were assessed according to MRI data. All patients were followed-up throughout at least 3-year., Results: Surgery time was 147 min, blood loss - 118 ml, hospital-stay - 7 days. Clinical parameters significantly improved in the follow-up period: ODI score decreased from 72 to 12 ( p =0.004), SF-36 PCS increased from 26.24 to 48.51 ( p =0.006) and MCS score increased from 29.13 to 53.68 ( p =0.002). According to MRI data, no tumor recurrences and severe muscle atrophy (>30%) were observed after 3 years in all cases. Superficial wound infection occurred in 1 (7.7%) case. There were normal neurological functions (ASIA type E) in all patients., Conclusion: Minimally invasive facetectomy through posterolateral approach with MI TLIF technology can be used for safe and effective resection of dumbbell-shaped schwannomas Eden type 2 and 3.

Introduction: Stereotactic radiosurgery is one of the main treatments for vestibular schwannomas (VS). Their feature is frequent post-radiation pseudoprogression. This may be due to hormonal status of patients., Objective: To analyze expression of progesterone and estrogen receptors in women and men with VS., Material and Methods: Immunohistochemical analysis of expression of progesterone (PR) and estrogen receptors (ER) after biopsy was performed in 240 patients with VS between 2018 and 2021. ER/PR expression was assessed in men ( n =120) and women ( n =120) in 3 age subgroups: young age (18-44 years), middle age (45-59 years) and old age (60-79 years). Each subgroup included 40 patients. Statistical analysis was performed using the Mann-Whitney test and MedCalc software., Results: ER expression is not typical for VS (men - 1 (0.01%), women - 3 (2.5%)). At the same time, PR expression was found in 29 (24.2%) men and 21 (17.5%) women. We found no significant difference in expression of ER and PR between men and women. However, variability in PR expression was revealed, i.e. predominance of this indicator in young women ( p =0.0463) and middle-aged men ( p =0.0110). Expression of PR was similar in elderly patients ( p =0.2382)., Conclusion: The established incidence of PR expression may be one of the probable causes affecting development and duration of VS pseudoprogression after radiosurgery without clear relationship between sex and age. Further prospective research is needed to predict the risks of pseudoprogression.

Schwannomatoses is a new classification unit for all the hereditary diseases caused by chromosome 22 damage followed by multiple benign neoplasms of the peripheral and central nervous system. Schwannomatosis occurs as a result of damage to different genes: NF2, SMARCB1, LZRT1, loss of heterozygosity of the long arm of chromosome 22. Nevertheless, clinical manifestations are similar. Molecular diagnostics not only confirms the diagnosis, but also predicts the course of disease. Thus, the most severe clinical manifestations are observed in patients with violation of semantic sequences and reading frame shift in exons 2-13 of the NF2 gene. A more favorable course with less number of tumors is observed in patients with somatic mosaicism. Stereotactic irradiation and surgery are the main treatment options for schwannomatosis. However, there is evidence of effective targeted therapy with bevacizumab (inhibitor of vascular endothelial growth factor). Bevacizumab is used in patients with bilateral vestibular schwannomas and high risk of hearing loss, as well as for intramedullary tumor growth control.