[Transsphenoidal surgery of craniopharyngioma: form palliative surgery to radical removal].

The paper presents basic principles of transsphenoidal craniopharyngioma surgery. Stages of methodology development. Steps of methodology development of such operations in the Institute are described--from palliative interventions to the high-tech modern radical surgery with the use of anterior extended approach. Additional stereotactic irradiation provides reliable control of the disease for a long period. The article mainly describes operative technique and contains preliminary analysis of the surgical results showing effectiveness and safety of endoscopic removal of craniopharyngioma.

[Thyrotropin secreting pituitary adenoma in a child: case report and literature review].

We present a case of 11-year old boy with Type 1 Autoimmune Polyglandular Syndrome and thyrotropin secreting pituitary adenoma, which was diagnosed by elevated TSH and thyroid hormones levels and MRI signs of pituitary tumor and without clinical symptoms of hyperthyroidism. He underwent partial resection of the tumor via transnasal approach and subsequent radiation therapy. Consequently 1 year after XRT patient developed growth hormone deficiency, 3.5 years later patient became euthyroid, and 5.5 years after treatment - hypothyroid. This is the first described case of coexistence of this 2 rare endocrine diseases in the same patient.

[Application of robotized radiosurgical system CyberKnife for the treatment of neurosurgical patients].

Robotized system for radiosurgery CyberKnife (Accuray Inc., USA) is the first device dedicated and optimized for advanced irradiation during 1-7 fractions (i.e. radiosurgery and hypofractionation). CyberKnife is characterized by elaborate guidance system, high precision of dose delivery, possibility of conformal dose distributions with high gradient of target borderline dose which is most important in proximity of critical structures. The first CyberKnife system in Russia was installed in Burdenko Neurosurgery Institute. The paper presents 2-year experience of treating patients using CyberKnife. From April 2009 till October 2011 896 patients were treated using CyberKnife. Mean age was 48 years. Overall number of sessions was 2626. Radiosurgical procedures were performed in 21.8% of patients. 91% of cases were treated for intracranial lesions. Limited follow-up period in all kinds of pathology demonstrated results consistent with standard fractionation or radiosurgery. The rates of observed complications were also comparable with accepted techniques. CyberKnife system plays significant role in everyday activity of department of radiation therapy. In careful and thorough selection of patients it allows efficient and high-quality treatment of patients with neurosurgical diseases.

[First experience of stereotactic radiation therapy for vestibular schwannoma using CyberKnife].

Currently stereotactic radiosurgery has become the treatment of choice in small vestibular schwannomas. This paper discusses our first experience of application of CyberKnife system for stereotactic irradiation of these tumors. From April 2009 till June 2011 we treated 62 patients (35 female and 27 male) with vestibular schwannomas. Stereotactic radiosurgery using CyberKnife system was performed in 33 patients. Mean tumor volume was 2 +/- 1.4 cm3. Hypofractionated treatment was used in 30 cases (31 tumor). Mean tumor volume reached was 7 +/- 6.2 cm3 (range - 0.5-31.3 cm3). In a case of a patient with NF2 simultaneous irradiation of bilateral tumors was performed. Most frequently we applied 3 fractions 6 Gy each (17 observations of 31, or 55%) and 5 fractions with mean dose 5 Cy (10 cases, or 32%). Follow-up period varied from 1 to 26 months (mean 9 +/- 4.5 months). By the end of this study (June 30, 2011) surgical resection was required in the only case of 47-years old male patient with cystic schwannoma of left vestibular nerve 5 months after radiation treatment, due to progressive growth of the cyst and increased brainstem compression. Tumor growth control was established in 97.5% of cases. Stabilization of auditory function was achieved in 77.5% of series. Effective hearing was preserved in 75% of patients. Facial nerve palsy after stereotactic radiation treatment was observed in 2 cases (3%). Incidence of trigeminal nerve dysfunction was significantly higher: sensation disturbances occurred in 6 (10%) patients: 3% after radiosurgery and 16.7% after hypofractionation. We did not obtain significant correlations between risk of cranial nerve complications and dosimetric or demographic factors. However we observed stable tendency: larger initial volume of the tumor and presence of trigeminal nerve dysfunction before treatment were poor prognostic factors for trigeminal neuropathy. Stereotactic irradiation using CyberKnife system is effective and sufficiently safe technique for management of vestibular schwannoma. The paper demonstrates high rates of tumor stabilization, hearing preservation and minimal incidence of complications associated with trigeminal or facial nerve.

[First experience of radiosurgical treatment of arteriovenous malformations using CyberKnife].

Radiation treatment techniques are essential in complex management of selected neurooncological, neurovascular and functional brain pathology. Stereotactic radiotherapy provides sufficient damage to the target (tumor, AVM, functional structures) with minimal impact on surrounding brain tissue. Development of stereotactic methods with X-ray guidance lead to expansion of indications for irradiation of intracranial and extracranial lesions. This paper represents the first experience of treating patients with AVMs using CyberKnife system in Russia. The technique of stereotactic radiotherapy (SRT) and radiosurgery (SRS) is described in details, as well as indications for SRT and SRS in different regiment of fractionation, possibilities of planning systems, with additional emphasis on specific complications, radiation-induced reactions and capabilities of neurovisualization methods in evaluation of radiation-induced damage of brain tissue.

[Stereotactic radiotherapy and radiosurgery in treatment of patients with deep-seated pilocytic astrocytomas].

Pilocytic astrocytoma (PA) is a low-grade glial tumor (WHO grade I) with predominant occurrence in pediatric patients. According to many authors, stereotactic radiosurgery (SRS) and radiotherapy (SRT) promote long-term remission or retardation of tumor progression in patients with in inoperable lesions after incomplete resection or recurrence. Therefore it is essential to determine the role of SRS and SRT in complex management of patients with deep-seated PA. Since April 2005 till May 2010 101 patient with intracranial PA was treated in department for radiation therapy of Burdenko Neurosurgical Institute. The series consisted of 70 pediatric patients (below 17 years inclusively) and 31 adults, of them--51 male and 50 female patients. Mean age was 15.1 years (9.8 years in children and 28.7 in adults). In 90 patients (89.2%) tumors were previously histologically verified (tumor resection in 83 cases and biopsy in 7). In 11 (10.8%) patients diagnosis of PA was based on clinical and neurovisualization data. In most cases SRT (66 (66.3%) patients) was preformed, the rest 35 (34.7%) patients were treated by SRS. Median follow-up from the onset of disease reached 52 months (2-228 months). Catamnestic data were available in 88 (87%) patients. By the end of catamnestic follow-up (December 2010) 87 (98.8%) patients treated by SRS and SRT were alive. Median follow-up from the start of radiation treatment was 22.7 months (6-60 months). Progression of tumor was observed in 20 patients (22.7%), in 18 of them due to cyst growth. 18 patients were reoperated. In 12 operated patients histological examination and its comparative analysis were performed. We found that alterations in the tumor tissue, accompanied by regression of solid component and progression of cystic portion, represent reactive-degenerative changes in the tumor as a consequence of radiation-induced pathomorphism. SRS and STR are effective techniques for treatment of patients with primary and recurrent PA despite regardless of localization of the tumor. There procedures should be performed shortly after non-radical resection. Control of tumor growth by the present time (median follow-up is 22.7 months) reaches 98%. "Progression" of the tumor due to enlargement of cystic portion shortly after SRT and SRS represents reactive-degenerative alterations in the tumor tissue and should not be evaluated as true recurrence; without neurological deterioration these cases do not require special treatment.

[Diffuse bithalamic astrocytomas in children and adults].

Diffuse bithalamic glioma is rare entity. A few cases have been described so far. We present the data of 13 patients (both children and adults) with diffuse bithalamic gliomas observed and treated at Burdenko Neurosurgery Institute within the period of 2004-2011. Age of patients varied from 3 to 29 y.o. Bithalamic gliomas appear as symmetric enlargement of both thalami on MRI with frequent spreading to adjacent structures (brainstem, temporal lobes). Histologically they appear as astrocytomas (Grade II-IV). Bithalamic gliomas posess different clinical course. There is no indication for surgical treatment because of diffuse growth of these tumors. Stereotactic biopsy is indicated to verify histological origin. Treatment of bithalamic gliomas confined with radio- and chemotherapy. In cases with obstructive hydrocephalus CSF diverting operations are indicated. Attempts of surgical excision lead to worsening of patient's neurological condition. Most patients with bithalamic gliomas have unfavorable prognosis. Tumors remain stable with adjuvant therapy for a very short period of time in most cases. Benign course of this pathology with long-term follow-up is observed only in a few cases.

[Stereotactic radiosurgery in treatment of patients with hypothalamic hamartomas].

Hypothalamic hamartoma (HH) is malformation of the brain manifesting by paroxysmal disorders (gelastic seizures) and endocrine disorders (mostly precocious sexual development). Surgical resection of HH is associated with the risk of severe neurological and neuroendocrine complications. Alternative ways of treatment are being investigasted. Stereotactic radiosurgery is one of the leading techniques in treatment of pharmacoresistant seizures due to high effectiveness and low complication rate. Since 2005 till 2009 7 patients with HH were treated in Burdenko Moscow Neurosurgical Institute. Age of patients varied between 9 months and 20 years 9 mean - 8.5 years). In all cases the disease manifested by gelastic seizures with frequency differing between 2-3 per months and 17 per day. All patients received long-term combined anticonvulsant treatment (using valproates, carbamazepine, lamotrigine, oxcarbazepine, topiramate) with temporary and insufficient effect or without any effect. In 4 patients frequency of seizures increased during anticonvulsant therapy. I patient had been operated (partial resection of HH) with temporary effect which consisted of decrease in frequency of seizures for 8 months; later frequency of paroxysms increased. Main indications to radiosurgical treatment included progressive course of disease, low effectiveness of anticonvulsant therapy and high risk of direct surgical treatment. 6 patients were treated using linear accelerator "Novalis" and 1 using "Cyber-knife". Treatment was performed under pharmacological sedation (midazolam, ketamine). Marginal dose was 11-18 Gy (mean 15.7 Gy). Volume of hamartomas was 0.3-3 cm3. Follow-up period varied between 3 and 50 months. Decreased frequency of seizures was observed in 100% of cases. Stereotactic radiosurgery is an effective and safe method of treatment for HH and may be considered as treatment of choice for pharmacoresistant seizures caused by HH.

[Linear accelerator-based stereotactic radiotherapy and radiosurgery in treatment of neurosurgical patients].

Radiation methods are essential in management of certain types of neurooncological, neurovascular and functional brain pathology. Application of stereotactic technique of irradiation allows sufficient damaging impact on target (tumor, AVM, functional structures) and maximal protection of surrounding brain tissues. Indications to radiation treatment of intracranial lesions are expanding with evolution of stereotactic methods. The paper deals with the first experience of linear accelerator-based treatment of patients with intracranial neurosurgical pathology in this country. Techniques of stereotactic radiotherapy (SRT) and radiosurgery (SRS), indications to SRS and SRT in different modes of fractioning are described in details. Additionally specific complications, radiation reactions and feasibility of neurovisualization in diagnosis of radiation-induced brain damage are discussed.

[Development of secondary resistance to dopamine agonists in a patient with giant prolactinoma].

Currently conservative treatment is therapy of choice in most patients with prolactinoma. However in 10-20% of them resistance to dopamine agonists occurs. In the majority of such cases resistance is initial, and only a few patients after good primary response to dopamine agonists develop so called "secondary" resistance ("escape" from effect). Alternative method of treatment in this situation is surgery, but in case of large invasive adenoma radical removal is often not possible. Consequently, radiation therapy may be feasible. Among 306 patients with macroadenomas examined in Burdenko Neurosurgical Institute (Moscow, Russia) only 2 (0.65%) developed "secondary" resistance to dopamine. In 1 case radiation therapy allowed effective control of tumor size and decrease of prolactin level. 1 case is described in details, and histological material was analyzed meticulously. Downregulation of D2R receptors in tumor cells may be one of the possible mechanisms of resistance to dopamine agonists.