[An anatomical study on the applicability of direct endoscopic exclusion of the ethmoid arteries for devascularization of the anterior skull base structures]. / Anatomicheskoe issledovanie vozmozhnosti priamogo éndoskopicheskogo vykliucheniia reshetchatykh arterii dlia devaskuliarizatsii struktur perednikh otdelov osnovaniia cherepa.

The anterior skull base structures are the site of initial growth of histologically different tumors. The difficulties in their removal are often associated with significant vascularization, which may limit the amount of resection due to abundant intraoperative blood loss. Midline tumors are primarily fed by the ethmoid arteries that are not accessible to embolization. The aim of this work was a comparative experimental study of various direct approaches to the ethmoid arteries. MATERIAL AND METHODS: The study was conducted on anatomical specimens of 12 cadaveric heads of deceased people without pathology of the anterior skull base structures, orbits, nasal cavity, and paranasal sinuses (24 sides). In all specimens, the internal and external carotid arteries were stained with silicone. During anatomical dissection, four surgical approaches for exclusion of the ethmoid arteries were studied: 1) transorbital approach to the arteries using a bicoronal incision; 2) endoscopic retro-caruncular approach; 3) endoscopic endonasal transethmoidal approach to the ethmoid artery canals; 4) endoscopic endonasal transethmoidal transorbital approach to the ethmoid arteries in the orbit. RESULTS: We described a surgical technique for exclusion of the ethmoid arteries using the approaches and analyzed their advantages and disadvantages. We formulated an algorithm for choosing the method for direct endoscopic exclusion of the ethmoid arteries, depending on the surgical approach chosen for removal of the tumor and features of the tumor extracranial spread. CONCLUSION: The decision on tumor devascularization is based on assessment of tumor blood supply (CT angiography or MR angiography data). Our study demonstrated the advantages and disadvantages of various approaches to the ethmoid arteries for their exclusion in order to early devascularize anterior skull base tumors. All these approaches are less traumatic and characterized by a good cosmetic and functional outcome.

[Variability and age-related features of the anatomy of the midline structures of the anterior skull base]. / Variabel'nost' i vozrastnye osobennosti anatomii sredinnykh struktur perednikh otdelov osnovaniia cherepa.

The article presents the literature data on the structural variability and age-related features of the midline anatomical structures of the anterior skull base (frontal sinus, ethmoid bone, anterior parasellar region, and medial orbital wall). This is the area of surgical interests of neurosurgeons and rhinosurgeons. The study objective is to analyze the literature data on the individual variability and age-related anatomy of these structures. The work is illustrated with original images from the authors' personal archive. The individual anatomical features of eloquent structures in the surgical area (structures within the surgical corridor, key anatomical landmarks, optic tract, internal carotid and ethmoidal arteries, etc.) should be considered in planning surgery in patients of all age groups because they can limit the view and the amount of safe manipulations or increase the risk of complications. The presented data may be useful for neurosurgeons and otolaryngologists whose surgical interests are focused on the midline structures of the anterior skull base.

[Tactics of reconstructive closure of basal defects after resection of midline tumors of the anterior skull base (a literature review)]. / Taktika plasticheskogo zakrytiia bazal'nykh defektov posle udaleniia sredinnykh novoobrazovanii perednikh otdelov osnovaniia cherepa.

The purpose of this review is to analyze the techniques used to reconstruct midline defects in the anterior skull base after transcranial and endoscopic endonasal resection of skull base tumors. We provide brief information on the technique for preparing various flaps, indications and contraindications, and advantages and disadvantages. We analyze the international experience in the use of vascularized and non-vascularized flaps as well as the existing algorithms for reconstruction of complex defects of the midline structures of the skull base. The literature data demonstrate the absence of a conventional tactics of reconstructive closure of the discussed defects. To resolve this issue, a meta-analysis in combination with an original prospective study is required.

[Choosing an anterior midline approach to skull base tumors]. / Vybor perednego sredinnogo dostupa pri opukholiakh osnovaniia cherepa.

The purpose of this review is to analyze used anterior midline approaches to the skull base, identify their advantages and disadvantages, and, after reviewing the literature data, submit a developed algorithm for choosing an optimal approach to the approval of colleagues. We provide brief information on approach techniques, indications and contraindications, and advantages and disadvantages as well as analyze international experience of using the discussed approaches. On the basis of literature data, we have developed a prototype algorithm for choosing an optimal approach to medial tumors of the anterior skull base. The situation of choosing an optimal approach reveals the absence of a clear understanding of the boundaries between capabilities and limitations of approaches. To solve this problem, an original prospective study is required.

[Long association tracts of the human white matter: an analysis of 18 hemisphere dissections and in vivo HARDI-CSD tractography]. / Dlinnye assotsiativnye provodyashie puti belogo veshchestva golovnogo mozga cheloveka: analiz dissektsii 18 polusharii i HARDI-CSD traktografii in vivo.

BACKGROUND: Anatomy of the conduction tracts of the cerebral cortex has been studied for a long time. Invention of diffusion tensor tractography renewed interest in this subject. The objectives of this work were to develop and improve protocols for dissection of the long association tracts of the human brain with studying the features of their segmentation, topography, and variability, compare the obtained data with the MR tractography data, and prepare for further clinical and anatomical studies. MATERIAL AND METHODS: We used 18 cerebral hemispheres (from 10 males and 8 females; 9 left and 9 right hemispheres). The mean age of cadavers was 68 years. Specimen were fixated in accordance with the Klingler technique. Immediately after collection, specimens were placed in a 10% formalin solution for at least 4 weeks. After that, the pia was removed; specimens were frozen at -20 °C for a week and then unfrozen in a 96% ethanol solution for a day. We performed 10 lateral dissections, 2 lateral dissections with isolation of the frontal aslant tract, 2 basal dissections, 1 combined basolateral dissection, 2 frontal dissections, and 1 medial dissection. At the time of dissection and after it, specimens were stored in a 96% ethanol solution. Modified, disposable, therapeutic wooden spatulas were used for manipulations. A microscope (magnification of 6-40x) was used in 2 lateral and 2 basal dissections. MR tractography (HARDI-CSD) was carried out in 5 healthy volunteers using a GE Signa HDxt MRI scanner a field strength of 3.0 T. RESULTS: We clearly identified the following fascicles: the arcuate fascicle (AF) and superior longitudinal fascicle (SLF) in 6/6 hemispheres on the right and in 5/6 hemispheres on the left, the inferior longitudinal fascicle (ILF) in 3/6 hemispheres on the left and in 4/6 hemispheres on the right, the uncinate fascicle (UF) in 4/4 hemispheres on the left and in 4/4 hemispheres on the right, and the inferior fronto-occipital fascicle (IFOF) in 4/4 hemispheres on the left and in 3/4 hemispheres on the right. Identification was less successful in the case of the frontal aslant tract (FAT) in 1/2 hemispheres on the left and in 0/2 hemispheres on the right. The used technique failed to identify the vertical occipital fascicle (VOF) of Wernicke, a segment of the superior longitudinal fascicle SLF I, and the middle longitudinal fascicle (MdLF). The MR tractography HARDI-CSD data were compared with the dissection data. We described in detail segmentation of the superior longitudinal, arcuate, and inferior fronto-occipital fascicles. Contradictory data were obtained for the superior longitudinal fascicle: a two-segment structure (SLFh and SLFv) was found in most (10/12) specimens, while a three-segment structure was revealed in the other (2/12) specimens (identified SLF II and SLF III). In the arcuate fascicle, the ventral and dorsal segments were successfully identified in 2/12 cases (1 left and 1 right), whereas identification failed in the other cases. During dissection of the inferior fronto-occipital fascicle, we could identify its surface layer in 1 of 8 cases (left) and its deep layer in one more case (left). CONCLUSION: Examination of the long association tracts using the Klingler technique has significant limitations in the fiber intersection areas (sagittal striatum). The frontal aslant tract was least studied; we proposed a special anterior dissection technique for its isolation. The superior longitudinal fascicle can have both the two-segment (10/12) and three-segment (2/12) structure. Investigation of the segmental anatomy of the long association tracts will be continued in further dissections. When planning neurosurgical interventions in the projection areas of the long association tracts, both preoperative HARDI-tractography and anatomical dissections ex vivo, based on the proposed protocols, can be recommended for the operating surgeon to master a three-dimensional picture of the tract topography.

[Surgical anatomy of the peri-insular association tracts. Part I.The superior longitudinal fascicle system]. / Khirurgicheskaya anatomiya periinsulyarnykh assotsiativnykh provodyashchikh putei. Chast' I. Sistema verkhnego prodol'nogo puchka.

AIM: To study the peri-insular association tract anatomy and define the permissible anatomical boundaries for resection of glial insular tumors with allowance for the surgical anatomy of the peri-insular association tracts. MATERIAL AND METHODS: In an anatomic study of the superior longitudinal fascicle system (SLF I, SLF II, SLF III, arcuate fascicle), we used 12 anatomical specimens (6 left and 6 right hemispheres) prepared according to the Klingler's fiber dissection technique. To confirm the dissection data, we used MR tractography (HARDI-CSD-tractography) of the conduction tracts, which was performed in two healthy volunteers. RESULTS: Except the SLF I (identified in 7 hemispheres by fiber dissection), all fascicles of the SLF system were found in all investigated hemispheres by both fiber dissection and MR tractography. The transcortical approach to the insula through the frontal and (or) parietal operculum is associated with a significant risk of transverse transection of the SLF III fibers passing in the frontal and parietal opercula. The most optimal area for the transcortical approach to the insula is the anterior third of the superior temporal gyrus that lacks important association tracts and, consequently, a risk of their injury. The superior peri-insular sulcus is an intraoperative landmark for the transsylvian approach, which enables identification of the SLF II and arcuate fascicle in the surgical wound. CONCLUSION: Detailed knowledge of the peri-insular association tract anatomy is the prerequisite for neurosurgery in the insular region. Our findings facilitate correct identification of both the site for cerebral operculum dissection upon the transcortical approach and the intraoperative landmarks for locating the association tracts in the surgical wound upon the transsylvian approach to the insula.

[Orbitozygomatic approaches to skull base tumors spreading into the orbit, paranasal sinuses, nasal cavity, and pterygopalatine and infratemporal fossae].

The paper analyzes application of orbitozygomatic approaches at the Department of Skull Base and Craniofacial Surgery of the Burdenko Neurosurgical Institute for a 14-year period. During this time, 723 patients were operated on using the orbitozygomatic approach, which has become the workhorse of surgery for skull base tumors spreading into the orbit, paranasal sinuses, and pterygopalatine and infratemporal fossae. The authors describe seven major modifications of the orbitozygomatic approach that they have used in their practice.

[Clinical guidelines for the use of intraoperative fluorescence diagnosis in brain tumor surgery].

In this paper, we present a review of current literature on the application of intraoperative fluorescence diagnosis and fluorescence spectroscopy using 5-aminolevulinic acid in surgery for various types of brain tumors, both alone and in combination with other neuroimaging methods. Authors' extensive experience with these methods allowed them to develop a set of clinical guidelines for the use of intraoperative fluorescence diagnosis and fluorescence spectroscopy in surgery of brain tumors.

[Orbitozygomatic approaches to the skull base].

The paper is written in the lecture format and dedicated to one of the main basal approaches, the orbitozygomatic approach, that has been widely used by neurosurgeons for several decades. The authors describe the historical background of the approach development and the surgical technique features and also analyze the published data about application of the orbitozygomatic approach in surgery for skull base tumors and cerebral aneurysms.

[Life quality of patients with benign tumors of the anterior and middle part of the skull base after surgery and during follow-up].

The results of surgical and combination therapy of 302 patients with benign tumors of the anterior and middle regions of the skull base with allowance for the functional outcomes (immediately after surgery and during the catamnestic follow-up) are reported. The Karnofsky and Rankin scales and the Anterior Skull Base Questionnaire (ASBQ) were used for the analysis. Radical tumor resection, as compared to partial resection, reduces the quality of life in the early postoperative period but increases it in future; the use of radiation therapy in combination treatment for patients with radically inoperable tumors does not worsen their quality of life in the late postoperative period.

[Optic nerve decompression in treatment of neoplasms involving optic canal].

Neoplasms extending to the optic canal is a diverse group of more than 15 histological types. Elimination of the optic nerve compression is crucial for favorable visual outcome. Material and method. We perform a prospective analysis of 97 patients with different neoplasms with involvement of the optic canal in whom surgery was performed in neurooncological department of Burdenko Neurosurgical Institute during the period from 2010 to 2012. Extent of resection and recurrence rates were determined by pre- and postoperative CT and MRI studies. Results. 97 patients (78 women and 19 men) were involved in the study. Mean age was 49,4 years. Patients were followed for mean of 15.9 months (1-36 month). Total resection was achieved in 54 (55.6%) patients, gross-total resection in 40 (41,2%), partial resection in 3 (3.2%). Underwent postoperative stereotactic radiation therapy 30 patients. There was no recurrence in a series of observations. 4 patients showed extension into both optic canals. Visual disturbances were the main presenting symptoms in 50 (51.5%) patients. 10 (10.3%) patients had normal visual status initially. Visual improvement after surgery was seen in (37%) of 87 patients with visual disturbances. Visual deterioration occurred in 17 (19%) patients. Transient visual deterioration occurred in 1 patient with recovery to the base level over time. The visual outcome was affected by the duration of the symptoms before surgery and the stage of visual disturbances according to the eyeground changes. Conclusions. Involvement of the optic canal is a common phenomenon in craniofacial tumors. Neoplasms extending to the optic canal is a diverse group of both the localization and histology. Decompression of the optic nerves is a crucial step in the surgical management of this neoplasms to optimize visual recovery and prevent tumor recurrence.

[Surgery of skull base tumors extending into the orbit, paranasal sinuses, nasal cavity, pterygopalatine and infratemporal fossas: treatment principles in certain types of tumors].

Following the paper focused on surgery of skull base tumors invading the orbit, paranasal sinuses, nasal cavities, pterygopalatine and infratemporal fossae, the authors discuss particular issues of surgical treatment of the most common craniofacial mass lesions, including meningiomas, juvenile angiofibromas, trigeminal nerve tumors, chondroid tumors, and others.

[Meningioma challenge: analysis of 80-year experience of Burdenko Neurosurgical institute and future perspectives].

The paper describes the history of meningioma surgery at Burdenko Neurosurgical Institute, analyses of accumulated series of patients and assesses effectiveness of different techniques for meningioma diagnosis and treatment of. We analyzed 15413 patients with meningiomas operated in Burdenko Neurosurgical Institute from 1932 to 2011. Mathematical analysis was performed using Statistica 6.0 program. Mortality rate during World War II reached a disastrous level of 45,8%, in 21st century it is below 1%. Temporary and permanent morbidity has also decreased. While in 1961 Karnofsky performance score was 71, in 2011 it became 83. The probability of postoperative tumour recurrence also diminished, from 40% in 1960-s to 29% in 1996 and presumably to 25% nowadays. Independent factors that influence the risk of recurrence are primary gross total resection, grade of anaplasia and radiation therapy. However, unreasonably aggressive surgery leads to significant increase of morbidity. Further improvement of surgical results in patients with meningiomas depends on implementation of new technologies for neurovisualization, abandoning extensive surgical approaches whenever possible, finding the "balance" between radical removal and expected functional outcome, wider application of radiosurgery and three-dimensional conformal radiation therapy.

[Tumors of the skull base, extending into the orbit, paranasal sinuses, nasal cavity, pterygopalatine and infratemporal fossa].

The first of two papers focusing on surgery of skull base tumors invading orbit, sinonasal cavities, pterygopalatine and infratemporal fossae the authors described foundation and development of craniofacial oncology as a new discipline in skull base surgery, modern approaches to diagnostic evaluation of craniofacial mass lesions and basic principles of surgical management.

[The first experience of skull base defect reconstruction using pedicled buccal fat pad after endoscopic endonasal resection of a craniofacial tumor]. / Pervyi opyt primeneniia peremeshchennogo loskuta zhirovogo tela shcheki na sosudistoi nozhke dlia plastiki defekta osnovaniia cherepa posle udaleniia kraniofatsial'noi opukholi éndoskopicheskim éndonazal'nym dostupom.

BACKGROUND: Buccal fat pad (BFP) is widely used in maxillofacial surgery for closure of oroantral and oronasal defects. V.A. Cherekaev et al. were the first who described application of pedicled BFP flap in reconstruction of anterior and middle skull base defects. This article focuses on a novel surgical technique - plastic closure of craniobasal defects via endonasal endoscopic approach. MATERIAL AND METHODS: We present a case of 12-year old male patient with advanced juvenile angiofibroma who was operated endoscopically using biportal transnasal-transantral approach. After removal of the tumor the defect of anterior cavernous sinus was reconstructed by translocated pedicled BFP flap supported by balloon-catheter. RESULTS: No postoperative complications such as cerebrospinal fluid nasal leakage were observed after withdrawal of balloon-catheter on the 4th day after surgery. The same day the patient was discharged in good condition. CONCLUSION: The proposed technique is promising and advantageous as part of complex multilayer skull base defect reconstruction after resection of extra-intracranial mass lesions due to preserved vascular supply of BFP flap. The method is safe and associated with extremely low risk of complications. We hope that the described flap will be appreciated and will take its place within the range of plastic materials for reconstruction of skull base defects in endoscopic endonasal approach.

[Intraoperative combined spectroscopy (optical biopsy) of cerebral gliomas]. / Intraoperatsionnaia kombinirovannaia spektroskopiia (opti-cheskaia biopsiia) gliom golovnogo mozga.

Clinical studies have revealed high selectivity of 5-ALA-induced protoporphyrin IX accumulation in different brain tumors. Modern methods of evaluation of tissues visible fluorescence are based on the qualitative analysis of the images. Up-to-date methods of combined spectral analysis allow fulfilling the intraoperative quantitative evaluation of the protoporphyrin IX content, as well as the scattering and absorption properties of a tissue. This paper presents a new method of the simultaneous analysis of hemoglobin concentration in oxygenated and reduced forms, tumor marker concentration (5-ALA-induced PP IX) and a new way to analyze the changes in the scattering properties of the tissues. The method is implemented by splitting the visible spectrum into intervals where hemoglobin and protoporphyrin IX have the characteristic peaks of absorption and fluorescence. The present method shows the dependence of the fluorescence index from the tumor grade. Combined spectroscopy (optical biopsy) can detect the differences between the subtypes of gliomas that are similar in the protoporphyrin IX fluorescence index. This method complements and enhances the diagnostic capabilities of spectroscopy, which is particularly important in the non-fluorescent glioma surgery.

[Intraoperative fluorescent visualization and laser spectrosopy in intrinsic brain tumor surgery].

Absence of well-defined borders of the glial tumor due to their infiltrative growth is one of the main issues in neurosurgery. A number of methods for intraoperative visualization are available today. The fluorescent metabolic navigation with 5-aminolevulinic acid (5-ALA) combined with quantitative laser spectroscopy is one of the latest technique. In our series of 99 consecutive patients with brain gliomas (WHO Grade I-IV) we found that visible fluorescence was observed in 68% of cases. Additional use of the laser spectroscopy could increase method sensitivity up to 74% due to accumulation of the protoporphyrine IX in nonfluorescense tumors. It was shown that there are some differences in quantitative fluorescence not only within same tumor (glioblastoma) but also in-between low- and high-grade gliomas. Intraoperative fluorescence and laser spectroscopy are effective and very helpful methods of intraoperative imaging in of intrinsic brain tumor surgery.

[Photodynamic diagnosis and laser biospectroscopy as an intraoperative guidance in neurosurgery].

Different techniques are used today in neurosurgery for intraoperative navigation, including metabolic guidance using 5-aminolevulinic acid (5-ALA). The article focuses on history of intraoperative photodynamic diagnosis (PDD), mechanisms of 5-ALA action, possibilities of its application in different areas of neurosurgery. In addition to visual assessment of fluorescence, laser biospectroscopy significantly increases the diagnostic value of PDD. Laser biospectroanalysis is described in details, wide perspectives of its application in neurosurgery are demonstrated.

[Cystic sphenoid wing meningioma mimicking astrocytic glioma].

In spite of rare incidence, cystic intracranial meningiomas deserve interest due to difficulties in correct preoperative diagnosis. Authors present a case report of a patient with cystic meningioma mimicking astrocytoma. In addition, review of literature is performed.

[Closure of anterior and middle skull base defects using pedicled buccal fad pad flap].

BACKGROUND: The problem of closure of skull base defects after resection of craniofacial tumors remains one of the most challenging in neurosurgery. Local pedicled grafts are preferred material for plasty. In this study authors present original technique of using a pedicled buccal fat pad (BFP) graft. Anatomy and functions of BFP are discussed in details. MATERIALS AND METHODS: Since 2004 till 2009 159 patients with anterior skull base mass lesions were operated in Moscow Burdenko Neurosurgical Institute using the discussed technique (male:female = 53:106, mean age was 47 years (10-72)). RESULTS: In 93% of cases pedicle BFP flap was applied, in 7%--free. Follow-up period ranged between 1 and 6 years. No postoperative CSF leak or other severe complication was observed in the series. CONCLUSION: BFP is characterized by absolute advantages--proximity of donor site and defect, simplicity of surgical technique, minimal postoperative discomfort and very low risk of benign complications. This paper is the first description of the suggested technique.