[Surgical treatment of patients with cerebral aneurysms in the acute stage of rupture: dynamics of results during 2006-2018]

Treatment of cerebral aneurysms in the acute stage of subarachnoid hemorrhage (SRH) especially on the background of cerebral vasospasm continues to be a difficult task.

OBJECTIVE

Assessment of dynamics of the surgical treatment results of patients with cerebral aneurysms in acute period of SRH.

MATERIAL AND METHODS

A comparative analysis of the results of patients' surgical treatment in NMRCN Burdenko about aneurysm in 1-21 days after hemorrhage was made. The following periods were selected: 2006-2014 (343 patients) and 2015-2018 (356 patients). Most patients had microsurgical operations in both periods. The tactics of choosing the surgery time was the main difference between the periods: particularly in 2015-2018 period the surgery was not postponed at patients with severe.

RESULTS

Analysing the post surgical mortality, it was found that since 2006 there is a consistent trend towards a decrease in the number of patients who died after surgery. When calculating the average post surgical mortality for the studied periods this trend is confirmed - number of lethal cases in 2015-2018 reliably decreased when comparing with 2006-2014 - from 6.8 till 3.2%; p=0.03. At the same time, the number of patients with outcome of vegetative status (from 0.3 till 5%).

CONCLUSION

The tactics of surgical treatment of patients with cerebral aneurysms in the acute period of SRH regardless of severity of patient's condition and time of hemorrhage did not lead to worse treatment. In contrast, post surgical mortality rates show a consistent decline. We associate this fact with a number of changes that have occurred in the management and treatment of patients. In particular, we have high hopes for developing new approaches to the treatment of vasospasm, which remains the leading cause of lethal cases. More definite conclusions will be made at the end of the treatment analysis of the respective patient groups.

[Primary pineal melanocytoma: clinical case and literature review]

Primary pineal melanocytomas are extremely rare pathologies and predominantly are clinically manifested by nonspecific symptoms of a pineal affect, which could be characteristic for tumors of different histological nature located in the same region. Also these tumors differ from other melanocytic tumors by their slow growth and relatively favorable clinical prognosis.

[Individual preoperative 3D modeling of vascular brain pathology]

The possibility of segmenting three-dimensional objects by DICOM-series is well known and available both on specialized workstations and on personal computers. The technique, however, is relatively rarely used in clinical practice, and we believe that the benefits of preoperative preparation using segmented 3D models are underestimated. The article is devoted to our experience in using segmentation of anatomical structures based on CT and MRI for preoperative preparation for surgical operations performed in neurosurgical departments on patients with vascular pathology. The paper discusses the types and possibilities of segmentation, provides some examples describing the clinical use of the technique.

[Microsurgical treatment of aneurysms of vertebral and posterior-lower cerebellar arteries: surgical approaches, exclusion options, treatment results]

Aneurysms of vertebral (VA) and posterior inferior cerebellar arteries (PICA) are relatively rare pathologies and account for 3.4% of the total number of intracranial aneurysms.

MATERIAL AND METHODS

The experience of microsurgical treatment of 67 patients with VA and PICA aneurysms in N.N. Burdenko National Medical Research Center for Neurosurgery of the RF Ministry of Health from 2012 to 2017 is presented.

RESULTS

Most patients underwent reconstructive microsurgical interventions: clipping of the aneurysm neck in 42 (62.7%) patients and complex clipping with the formation of arterial opening - in 10 (14.9%). Exclusion of the aneurysm together with the carrier artery (trapping, proximal clipping) was performed on 10 (14.9%) patients. In 5 (7.5%) patients, deconstruction of the carrier artery of the aneurysm was performed after creating local anastomoses. The radical exclusion of aneurysms in the studied group was 95.5%. Postoperative dysfunction of the caudal group of cranial nerves was detected in 11 (16.4%) patients. There were no lethal outcomes, or cases with vegetative status outcomes.

CONCLUSION

Microsurgical intervention is an effective way to treat VA and PICA aneurysms, subject to the principles of patient selection based on existing treatment algorithms as well as adherence to an interdisciplinary approach.

[A favorable outcome of surgical treatment and intensive care in a child admitted in a severe condition in the setting of aneurysmal subarachnoid hemorrhage (a clinical case and literature review)]

Treatment of children in the acute stage of hemorrhage from cerebral aneurysms is based on clinical cases reported in the literature and descriptions of small series of observations. There are no studies that enable the development of evidence-based approaches to intensive care in treatment of children with aSAH. We present a clinical case with a favorable outcome of complex treatment in a child admitted to the Burdenko Neurosurgical Institute at an extremely severe condition. The efficacy of treatment was based on a timely urgent neurosurgical intervention and adequate intensive therapy in the form of extended neuromonitoring with continuous measurement of intracranial pressure, which enabled using the whole complex of measures for timely management of intracranial hypertension. A favorable outcome (a GOS score IV) after this severe aneurysmal SAH indicates that there are no absolute contraindications for neurosurgical treatment of children with cerebral aneurysms.

[Oculomotor nerve neurinomas. Case reports and a literature review]

Oculomotor nerve neurinoma not associated with neurofibromatosis type II is an extremely rare pathology. According to the topography, cisternal, cisternocavernous, cavernous, orbitocavernous, and orbital tumor groups are distinguished. The clinical picture of the disease is characterized mainly by either oculomotor disorders or pyramidal symptoms, depending on the tumor localization. Neurinomas of the oculomotor nerve rarely occur without oculomotor disorders. However, in some patients with these tumors, the third nerve function remains intact. In this paper, we present clinical cases of two patients with oculomotor nerve neurinomas and analyze the relevant literature.

[Intracisternal administration of verapamil for the prevention and treatment of vasospasm in patients after microsurgical treatment of cerebral aneurysms in the acute period of hemorrhage]

The first results of intracisternal administration of verapamil for the prevention and treatment of cerebral vasospasm (CVS) in patients in the acute period of subarachnoid hemorrhage (SAH) after microsurgical clipping of cerebral aneurysms are presented.

OBJECTIVE

Safety assessment of the method of prolonged intracisternal infusion (PII) of verapamil.

MATERIAL AND METHODS

Over the period from May 2017 to December 2018, 42 patients were included in the study, who underwent clipping of aneurysm of the anterior segments of the Willis circle. Most patients (78.6%) were operated during the first 6 days after SAH. For each patient, a thin silicone catheter was installed, through which verapamil was infused. A prerequisite was the installation of external ventricular drainage and opening of the lamina terminalis. The daily dosage of verapamil varied from 25 to 50 mg of the drug diluted in 200-400 ml of isotonic sodium chloride solution. The indication for the use of the PII method was the presence of one of the following factors: a score on the Hunt-Hess scale from III to V, 3 or 4 points on the Fisher scale, confirmed angiographically by the CVS before the operation.

RESULTS

The PII procedure was performed from 2 to 5 days. The average dose of verapamil was 143.5±41.2 mg additionally, in the presence of an angiographically confirmed CVS accompanied by clinical manifestations, 14 (33.4%) patients received intra-arterial injection of verapamil in several stages, with individual selection of the drug dose. The formation of new cerebral ischemic foci of vasospastic genesis was observed in only 1 (2.4%) patient. No infectious intracranial complications were noted. The average follow-up period was 297.6±156.1 days. Long-term treatment outcomes, assessed by a modified Rankin scale from 0 to 2 points, were observed in 83.3% of patients. There were no outcomes such as vegetative status and no deaths. The frequency of liquorodynamic disorders, as well as epileptic syndrome did not exceed that among patients with SAH according to the literature.

CONCLUSION

The study has confirmed the safety of prolonged PII. The efficacy of the method, compared with other methods for CVS treatment requires further investigation. The first results look quite promising: the observation shows a low percentage of new foci of cerebral ischemia and the absence of deaths associated with it. In patients with severe CVS, the efficacy of the PII method is increased when combined with intra-arterial administration of verapamil.

[Technical features and complications of cranioplasty in patients after decompressive craniectomy in the acute period of subarachnoid hemorrhage]

Decompressive craniectomy is used for arresting hypertension-dislocation syndrome developing in seriuos patients in the acute period of subarachnoid hemorrhage. After stabilization of the patient's neurological and somatic status, cranioplasty is performed for protective, cosmetic, and therapeutic purposes. The most common surgery in these patients is skull repair using an autologous bone graft. Before cranioplasty, the patient's bone is preserved in two ways: cryopreservation or subcutaneous implantation to the anterior abdominal wall area. Recently, there have been numerous reports of early and delayed complications of cranioplasty with autologous bone grafts. The use of artificial grafts may reduce the risk of postoperative complications compared to an autologous bone graft. Previously, 'freely' or 'manually' simulated biopolymers were used. At present, they are rarely used for repair of extensive defects due to a poor cosmetic result. However, the advent of stereolithographic modeling and computer modeling of artificial grafts has improved the cosmetic result of this surgery. The purpose of this study is to assess the risk of postoperative complications of cranioplasty as well as to define the criteria for choosing a cranioplasty technique.

[Principles of surgical treatment for patients with asymptomatic aneurysms and cerebral aneurysms in the cold period after spontaneous intracranial hemorrhages]

Surgical treatment of patients with cerebral aneurysms still remains one of the most important issues of cerebrovascular neurosurgery, which is associated with both complexity of treatment and risks posed by the disease. The purpose of this publication is to discuss the recommendations and algorithms adopted at the Neurosurgical Institute for choosing surgical treatment of patients with single and multiple intracranial aneurysms based on the clinical course of disease and anatomical morphological classifications of aneurysms. The study was based on a large clinical material: we analyzed treatment outcomes in 1,621 patients (2009-2017); of these, 966 (59.5%) patients were operated on using microsurgical techniques, and 655 (40.4%) patients underwent endovascular surgery. Surgical treatment of patients with cerebral aneurysms has been performed in close cooperation between two vascular (microsurgical and endovasal) departments, using the latest technical innovations.

[Chiasm and optic nerve glioma manifested as hemorrhage (two clinical cases and a literature review)]

The article presents two rare clinical cases of low-grade (WHO grade I-II) glioma of the anterior visual pathway structures, the chiasm and optic nerves, in adults. The feature of these cases was the benign nature of a chiasm and optic nerve glioma in adults as well as its presentation in the form of hemorrhage to the tumor and parenchymal and subarachnoid space, which to some extent complicated making the correct diagnosis. Removal of an intracerebral hematoma and open tumor biopsy were performed in one case, and removal of a hematoma and partial tumor resection followed by radiotherapy were performed in the other case.

[Intracranial neurenteric cysts: experience of the Burdenko Neurosurgical Institute in the XXIth century]

We present a series of cases of a rare pathology, intracranial neuroenteric cysts, a review of the international literature, and the experience in treating this pathology.

MATERIAL AND METHODS

Seven patients with intracranial neuroenteric cysts underwent surgery at the Neurosurgical Institute in the period between 2000 and 2015.

CONCLUSION

The main and only technique for treatment of intracranial neurenteric cysts is their resection.

[Transient enlargement of craniopharyngioma cysts after stereotactic radiotherapy and radiosurgery]

Stereotactic radiotherapy/radiosurgery (RT/ES) is an effective technique for treating craniopharyngiomas (CPs). However, enlargement of the cystic part of the tumor occurs in some cases after irradiation. The enlargement may be transient and not require treatment or be a true relapse requiring treatment.

MATERIAL AND METHODS

In this study, we performed a retrospective analysis of 79 pediatric patients who underwent stereotactic RT or RS after resection of craniopharyngioma.

RESULTS

Five-year relapse-free survival after complex treatment of CP was 86%. In the early period after irradiation, 3.5 months (2.7-9.4) on average, enlargement of the cystic component of the tumor was detected in 10 (12.7%) patients; in 9 (11.4%) of them, the enlargement was transient and did not require treatment; in one case, the patient underwent surgery due to reduced visual acuity. In 8 (10.1%) patients, an increase in the residual tumor (a solid component of the tumor in 2 cases and a cystic component of the tumor in 6 cases) occurred in the long-term period after irradiation - after 26.3 months (16.6-48.9) and did not decrease during follow-up in none of the cases, i.e. continued growth of the tumor was diagnosed. A statistical analysis revealed that differences in the terms of transient enlargement and true continued growth were statistically significant (p<0.01).

CONCLUSION

Enlargement of a craniopharyngioma cyst in the early period (up to 1 year) after RT/RS is usually transient and does not require surgical treatment (except cases where worsening of neurological symptoms occurs, or occlusive hydrocephalus develops).

[Reasonability and efficacy of decompressive craniectomy in patients with subarachnoid hemorrhage after microsurgical aneurysm exclusion]

In recent years, the so-called primary or preventive decompressive craniectomy (DC) has been increasingly used in patients with aneurysmal subarachnoid hemorrhage (SAH). The main goal of the technique is prevention of refractory intracranial hypertension (ICH) and its consequences.

PURPOSE

The study purpose was to define the CT criteria for reasonability and efficacy of DC as well as clarification of the indications for preventive DC in patients with SAH after microsurgical aneurysm exclusion.

MATERIAL AND METHODS

The study included 46 patients who underwent microsurgical clipping of aneurysms and DC in the period between 2010 and 2016. All patients underwent surgery in the period of 1 to 12 days after SAH. Preventive DC (imultaneously with clipping of aneurysms) was performed in 38 patients. Secondary (delayed) DC was performed in 8 patients.

RESULTS

Mortality in a group of all patients with DC was 15.2%. Preventive DC was considered as 'reasonable' when the patient had signs of cerebral edema in the postoperative period. The X-ray criteria of reasonable DC included a more than 5 mm brain prolapse into the trephination defect or a lateral dislocation of more than 5 mm. If the patient had no prolapse and dislocation in the postoperative period, DC was considered 'unreasonable'. Among patients with ICH in the postoperative period, including 20 patients with reasonable preventive DC and 8 patients with delayed DC, mortality was 25%. The CT signs of efficient DC were found to be a more than 5 mm brain prolapse into the trephination defect in combination with a decrease in the lateral dislocation less than 5 mm. All seven patients with inefficient DC in our group died. To clarify the indications for preventive DC, we analyzed various preoperative factors in patients with reasonable and unreasonable DC.

CONCLUSION

In most cases, preventive DC in microsurgical aneurysm exclusion is indicated for patients in an extremely grave condition (Hunt-Hess Grade V), a lateral displacement of the mline structures of more than 5 mm, an intracranial hematoma of over 30 mL, and symptoms of acute cerebral ischemia (pronounced cerebral vasospasm and emerging ischemic foci).

[MR tractography in diagnosis and choice of a neurosurgical approach to basal ganglia tumors]

We describe two cases of surgical treatment of well-circumscribed basal ganglia tumors. The choice of a neurosurgical approach to a deep tumor was based on the MR tractography data and depended on the course and dislocation extent of the corticospinal tract. MR tractography provides information on the course and dislocation or destruction extent of the corticospinal tract running in the internal capsule and brainstem and clarifies the exact location of a tumor within the basal ganglia. This information promotes the choice of an optimal approach for radical resection of well-circumscribed tumor, leading to improvement in neurological symptoms and patient's quality of life.

[Preoperative and postoperative ophthalmic symptoms in patients with space-occupying lesions of the midbrain and pineal region]

The most common clinical manifestations of space-occupying lesions of the midbrain and pineal region are oculomotor and pupil disorders and ophthalmoscopic signs of intracranial hypertension.

PURPOSE

To identify patterns of neuro-ophthalmic symptoms before and after surgical treatment in patients with space-occupying lesions of the midbrain and pineal region.

MATERIAL AND METHODS

We analyzed neurological symptoms in 231 patients with space-occupying lesions of the midbrain and pineal region before and after surgical treatment. Malignant tumors were detected in 121 patients; benign tumors were present in 73 patients; 37 patients were diagnosed with pineal gland cysts. Patients with suspicion of germinoma underwent a tumor biopsy only; the other patients underwent tumor resection.

RESULTS AND DISCUSSION

Before surgery, oculomotor and pupil disorders were detected in more than half of the (67%) patients; ophthalmoscopic signs of intracranial hypertension were present in 38% of the patients. Neuro-ophthalmic symptoms significantly more often occurred in patients with malignant tumors. Midbrain symptoms were significantly more pronounced in germ cell tumors than in other malignant neoplasms. In the early postoperative period after tumor resection, deterioration of oculomotor and pupillary functions occurred in 46% of cases; there were no changes in 51% of cases; improvement occurred in 3% of cases. After tumor biopsy, symptoms in all patients with germinomas remained at the preoperative level. Developed symptoms partially regressed in the long-term period, and finally, only 29% of patients had deterioration of oculomotor and pupillary functions compared to the preoperative level.

[Severe postoperative intracranial hemorrhagic complications in a neurosurgical patient with von Willebrand disease not diagnosed before surgery (a case report and literature review)]

The article describes a rare clinical case of a patient with previously undiagnosed von Willebrand disease and basal meningioma; an intracranial neurosurgical intervention was complicated by delayed intracranial hematomas, both at the resected tumor site and distantly. The diagnosis of von Willebrand disease was established only after special hematology tests and only after surgery. Despite the use of specific therapy, the patient died due to intracranial hemorrhagic complications in the postoperative period. The paper discusses the problem of preoperative diagnosis of asymptomatic hemostasis disorders in neurosurgical patients and potential ways of its solution.

[Intra-arterial administration of verapamil for prevention and treatment of cerebral angiospasm after SAH due to cerebral aneurysm rupture]

AIM

The study purpose was to analyze the efficacy of intra-arterial administration of verapamil (IAV) in the treatment of angiospasm in SAH patients and to determine optimal parameters of the procedure. A number of studies demonstrated the efficacy of intra-arterial administration of vasodilators, in particular verapamil, in the treatment of angiospasm after aneurysmal SAH, which served the basis for inclusion of this method in the recommended protocol for treatment of SAH patients [1-7].

MATERIAL AND METHODS

We analyzed the efficacy of IAV in 35 patients in the acute period of SAH, with 77.2% of the patients having a Hunt-Hess score of III-V. The inclusion criteria were as follows: IAV within two weeks after SAH; excluded aneurysm; verapamil dose per administration of at least 15 mg; follow-up for at least three months. Efficacy endpoints were as follows: changes in spasm according to angiography and transcranial dopplerography (TCDG); development of ischemic lesions; clinical outcome according to the modified Rankin scale.

RESULTS

A total of 76 IAV procedures were performed. The verapamil dose per procedure was 36.7±9.7 mg, on average; the number of procedures varied from 1 to 5. One arterial territory was treated in 12 cases, two arterial territories were treated in 48 cases, and three arterial territories were treated in 15 cases. Typical adverse reactions included decreased blood pressure, a reduced heart rate, and elevated ICP. In all cases, TCDG revealed signs of reduced angiospasm - a 20-40% decrease in the LBFV in the M1 MCA. Four (11.4%) patients died; of these, only one died due to angiospasm progression. On examination at 3 months or more after discharge, favorable outcomes were observed in 74.3% of cases.

CONCLUSION

IAV is associated with a low risk of significant complications. IAV should be performed under control of systemic hemodynamics and ICP. The indications for IAV include signs of moderate worsening or severe angiospasm according to TCDG and/or angiography. The IAV procedure may be performed every day. Further clarification of the IAV procedure and evaluation of clinical outcomes under prospective study conditions are required.

[A rare case of diencephalic cachexia in an adult female with cranio-pharyngioma]

Diencephalic cachexia (DС) is progressive weight loss despite a normal caloric intake and a satisfactory state of health, which is caused by hypothalamic lesions. This is a rare (about 100 cases were reported) and potentially fatal disorder of unknown pathogenesis. At present, there is no effective pharmacological therapy for the disorder. Cachexia may regress only if the tumor reduces in size, therefore the timely diagnosis and treatment are of vital importance for the patient. DС is typical of early childhood, and only a few cases have been reported in adults. We present a rare case of DС in a 24-year-old female with papillary craniopharyngioma.

[On the classification of large and giant paraclinoid internal carotid artery aneurysms]

Large and giant intradural ICA aneurysms or the so-called paraclinoid aneurysms are a surgical challenge requiring high qualification of the neurosurgeon. Despite numerous publications on this topic, there is still no generally accepted classification of paraclinoid aneurysms. In this paper, we analyzed the definitions and classifications of paraclinoid aneurysms, which were available in the medical literature. The paper presents our own surgical classification of paraclinoid ICA aneurysms, which has been developed by Prof. Sh.Sh. Eliava and co-authors at the Burdenko Neurosurgical Institute. The classification is based on the aneurysm neck position relative to the ICA wall, aneurysm dome direction, and type of aneurysm clipping.

[Gene mutations in patients with hereditary cavernous malformations]

AIM

To identify mutations in cerebral cavernous malformation (CCM) genes in patients with hereditary and sporadic CCMs in the Russian population.

MATERIAL AND METHODS

Blood samples from 73 randomly selected patients, including 29 MRI-confirmed familial cases, 8 clinically confirmed familial cases and 38 so-called sporadic cases, were examined. A search for large deletions/duplications was performed using multiplex ligation-dependent probe amplification (MPLA). For MLPA-negative samples, the whole genome sequencing was performed to search for single nucleotide polymorphisms (SNP).

RESULTS

Deletions in three genes (ССМ1, ССМ2, ССМ3) were identified in 14 patients, including 5 without definitely established familial type, in whom the familial character of disease was not confirmed by clinical and neuroimaging results. SNP mutations were found in 13 patients, CCM gene mutations in 27. Mutations were detected in 91.7% of familial cases. In two patients, new CCM3 deletions were identified. Gene distribution was as follows: 60.7 for CCM1, 32.2 for CCM2 and 7.1% for CCM3. In two members of a family with hereditary CCMs, no high effect mutations in the known CCM genes were found. Patients with mutations had greater severity of disease. Two patients with CCM3 mutations demonstrated the most aggressive clinical course. De novo formation and growth of CCM were observed only in patients with mutations.

CONCLUSION

The distribution of pathogenic mutations in known CCM genes is consistent with other large-scale studies. Familial CCMs are associated with more severe disease course and may be caused by mutations beyond the known CCM genes.

[A clinical and neuropsychological study of patients before and after resection of third ventricle colloid cysts]

The literature lacks studies of cognitive impairments in large groups of patients after resection of third ventricle colloid cysts.

AIM

To evaluate cognitive impairments in patients before and after resection of third ventricle colloid cysts.

MATERIAL AND METHODS

We performed a clinical and neuropsychological study of 52 patients with third ventricle colloid cysts using the Luria method (1962). Forty three patients were examined before and after cyst resection in the early postoperative period (three patients in this group were also examined in a long-term period of 3-7 months after surgery). Forty one patients were operated on using the transcallosal approach, and two patients were operated on using the subtentorial-supracerebellar transchoroidal approach. The other patients were examined only before or after surgery. The patients' age ranged from 14 to 61 years; the mean age was 33.8 years; the median age was 29 years.

RESULTS

On examination before surgery, cognitive impairments were minimal in 5 patients without clear signs of hydrocephalus. Impairments of memory and dynamic praxis, mild spatial disorders, and psychological inertia were observed in other patients with hydrocephalus. There was no significant difference in the state of cognitive functions between patients with and without stagnation in the fundus. On examination on day 3-6 after transcallosal surgery, several groups of patients were identified. Eight patients had an improvement in cognitive functions, which might be related to postoperative resolution of hydrocephalus. In 15 patients, changes in mnestic functions were insignificant. This group consisted of the youngest patients with a median age of 24 years. Korsakoff syndrome and disorientation were detected in 5 patients. This was the oldest age group, with a median age of 48 years. In other 13 patients, aggravation of mnestic disorders was moderate. Similar memory impairments were detected in the case of the subtentorial-supracerebellar approach. Memory disorders progressively regressed in all patients.

CONCLUSION

Postoperative memory impairment of a varying degree was found in 21 out of 43 patients, with adhesions between the cyst capsule and fornix being observed only in 5 patients. In this case, no injury to the fornix was intraoperatively observed. We discuss the role of the age factor, cyst size, and technical surgical difficulties in the pathogenesis of memory disorders in the absence of injury to the calvarium during colloid cyst resection.

[Application of intraoperative electromagnetic frameless navigation in transcranial and endoscopic neurosurgical interventions]

The paper summarizes the experience in using a system of electromagnetic intraoperative frameless navigation in various neurosurgical pathologies of the brain. The electromagnetic navigation technique was used for 102 operations in 98 patients, including 36 transnasal endoscopic interventions. There were no intraoprtative and postoperative complications associated with the use of the system. In the process of using the system, factors influencing the accuracy of navigation and requiring additional control by the surgeon were identified.

PURPOSE

The study purpose was to evaluate the use of electromagnetic navigation in surgical treatment of patients with various brain lesions.

MATERIAL AND METHODS

The system of electromagnetic navigation was used for 102 operations in 98 patients (42 males and 56 females, including 18 children; median age, 34.8 years (min, 2.2 years; max, 69 years)) in the period from December 2012 to December 2016. In 36 patients, the system was used for endoscopic interventions. In 19 patients, electromagnetic navigation was used in combination with neurophysiological monitoring.

RESULTS

In our series of cases, the frameless electromagnetic navigation system was used in 66 transcranial operations. The mean error of navigation was 1.9±0.5 mm. In 5 cases, we used the data of preoperative functional MRI (fMRI) and tractography for navigation. At the same time, in all 7 operations with simultaneous direct stimulation of the cortex, there was interference and significant high-frequency noise, which distorted the electrophysiological data. A navigation error of more than 3 mm was associated with the use of neuroimaging data with an increment of more than 3 mm, image artifacts from the head locks, high rate of patient registration, inconsequence of touching points on the patient's head, and unsatisfactory fixation to the skin or subsequent displacement of a non-invasive localizer of the patient. In none of the cases, there was a significant effect of standard metal surgical tools (clamps, tweezers, aspirators) located near the patient's head on the navigation system. In two cases, the use of massive retractors located near the patient's localizer caused noise in the localizer and navigation errors of more than 10 mm due to significant distortions of the electromagnetic field. Thirty-six transnasal endoscopic interventions were performed using the electromagnetic frameless navigation system. The mean navigation error was 2.5±0.8 mm.

CONCLUSION

In general, electromagnetic navigation is an accurate, safe, and effective technique that can be used in surgical treatment of patients with various brain lesions. The mean navigation error in our series of cases was 1.9±0.5 mm for transcranial surgery and 2.5±0.8 mm for endoscopic surgery. Electromagnetic navigation can be used for different, both transcranial and endoscopic, neurosurgical interventions. Electromagnetic navigation is most convenient for interventions that do not require fixation of the patient's head, in particular for CSF shunting procedures, drainage of various space-occupying lesions (cysts, hematomas, and abscesses), and optimization of the size and selection of options for craniotomy. In repeated interventions, disruption of the normal anatomical relationships and landmarks necessitates application of neuronavigation systems in almost mandatory manner. The use of electromagnetic navigation does not limit application of the entire range of necessary intraoperative neurophysiological examinations at appropriate surgical stages. Succession in application of neuronavigation should be used to get adequate test results.

[Surgical management of venous compression causing trigeminal neuralgia]

Venous compression is a rare cause of trigeminal neuralgia (TN). Vascular decompression of the trigeminal nerve root, as the only etiopathogenetic treatment of trigeminal neuralgia, is a well-known procedure that is extensively used at various neurosurgical clinics. As the number of interventions for TN increases, the absolute number of surgeries for eliminating venous compression of the trigeminal nerve also grows. Five hundred TN patients underwent surgery at the Neurosurgical Institute in the period from 2000 to 2015. The diagnosis was made based on the criteria of the International Classification of Headache Disorders, the 3rd edition, (ICHD-3) and the Burchiel classification. The study included 211 males and 289 females. The median age was 57 years. All patients had typical TN pain with a unilateral distribution. Two or more branches were affected in 90 patients; one branch was predominantly affected in 10 patients. The median disease duration was 16 months. The median visual analog scale (VAS) score was 8 (very severe persistent pain). In all cases, the patients underwent surgery using the retrosigmoid suboccipital approach. The median postoperative follow-up was 36 months. The aim of this work is to summarize the first experience of the Neurosurgical Institute in surgical treatment for venous compression of the Vth nerve root and suggest methods increasing the efficacy of vascular decompression in patients with this disease.

[The principles for choosing a surgical technique for patients with acute cerebral aneurysm rupture]

The article describes the principles for choosing a surgical technique for patients with cerebral aneurysms in acute subarachnoid hemorrhage. The principles were developed based on the experience gained at the Burdenko Neurosurgical Institute. Microsurgical and endovascular treatment options are considered.