[Enhanced Natural Killers with CISH and B2M Gene Knockouts Reveal Increased Cytotoxicity in Glioblastoma Primary Cultures]

In an experimental study using the CRISPR/Cas9 system, "enhanced" NK cell lines with knockout of CISH, the gene for the CIS protein (a negative regulator of NK cytotoxicity), as well as two lines with a knocked-out β2-microglobulin gene, which provides membrane exposure of MHC class I, were obtained from two parental lines of human natural killers (YT wild type and YT-VAV1^(+) overexpressing the VAV1 cytotoxicity enhancing protein). The knockout efficiency was determined by real-time PCR as well as by flow cytometry with specific antibodies. The resulting CISH^(-/-) or B2M^(-/-) knockout lines were tested for cytotoxicity in primary monolayer cultures of human glioblastoma multiforme. The cytotoxicity of the lines was assessed using a cell analyzer that records the cell index based on cell impedance. YT-CISH^(-/-) has been shown to be significantly more effective than wild-type YT in eliminating primary glioblastoma cells in an in vitro cell monolayer experiment. The cytotoxicity of the YT-VAV1^(+)-CISH^(-/-) and YT-VAV1^(+)B2M^(-/-) lines against glioblastoma cells was the highest, but overall, it did not significantly differ from the initially increased cytotoxicity of the YT-VAV1^(+) line. The lines of NK-like cells obtained may serve as a prototype for the creation of "enhanced" allogeneic and autologous NK- and CAR-NK cells for the immunotherapy of glioblastoma multiforme.

[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.

[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.

[The specific features of the anatomical structure of the artery of labyrinth (an anatomical and topographical study)]

The objective of the present work was to study syntopy of the artery of labyrinth using block-preparations of the posterior cranial fossa, variants of its branching-off from the vertebro-basiliar basin (VBB), and peculiar features of its anatomical structure. A total of 12 block-preparations of the posterior cranial fossa were available for the investigation. They were preliminarily stained with red latex and fixed in a three-point system. These procedures were followed by retrosigmoid craniotomy, opening of dura mater in the supero-lateral part of the cerebellomedulllary cistern, traction of the cerebellum, and blunt separation of the basiliar artery (BA). Variants of branching of the antero-inferior cerebellar artery (AICA) and branching of the artery of labyrinth from AICA were studied. It was shown that the artery of labyrinth branches off from the antero-inferior cerebellar artery in 100% of the cases. The latter artery formed a loop in 14% of the cases (3 ears). The average diameter of the labyrinth artery was 0.32 mm and its mean area 0.06 sq.cm. The artery of labyrinth branched off from the posterior para-stem segment of the antero-inferior cerebellar artery in 42.6% of the cases (9 ears), and from the anterior para-stem segment of AICA in 14.2% of the cases (3 ears). Within the conventional «rhombus», the artery of labyrinth was straight in 76.2% of the cases (16 ears) and arc-shaped in 23.8% (4 ears).

[Anatomic rationale for a transmaxillary access to the cavernous sinus]

W. Couldwell et al. were the first to propose a transmaxillary access to the cavernous sinus in 1997. The authors showed that this approach was low-invasive and cosmetic and it ensured visualization of different nervous formations of the cavernous sinus and the intracavernous segment of the internal carotid artery. This study was undertaken to study microsurgical anatomy, to simulate a transmaxillary access, to demonstrate its expediency, and to assess the use of endoscopic techniques when this access was applied. The study was conducted in 3 steps: 1) a craniometric study on 33 skulls and 25 craniograms to examine the craniological and geometric parameters of the anatomy of the osseous structures included into the transmaxillary access; 2) simulation of the access on the osseous structures of the skull (2 sides); by including anterior and posterior maxillotomy and bone drilling-out around the round foramen; 3) microsurgical preparation--dissection was performed on 3 head samples (5 sides) at the Laboratory of Microneurosurgical Anatomy, Acad. N. N. Burdenko Research Institute of Neurosurgery, Russian Academy of Medical Sciences. Endoscopy was tested when the transmaxillary access was applied. The results were as follows: 1. The depth of the access failed to correlate with the shape of the skull. The operative observation angle averaged 18-23 degrees. 2. Simulation of the transmaxillary access on the dried skull made it possible to visualize the medial portion of the infratemporal fossa, by enlarging the pterygpid-maxillary fissure. The bone drilling-out boundaries for the skull base were defined. 3. Microsurgical dissection after removal of the posterior maxillary sinus wall and opening the pterygopalatine fossa. The topography of the maxillary artery and nerve was studied. After drilling out the bone of the skull base, the lower wall of the cavernous sinus was crescent. The cavernous sinus was opened as far as possible both above the maxillary nerve and between the second and third branches of the trigeminal nerve.

CONCLUSIONS

1. The access is deep and narrow, yet low-traumatic. 2. It may be the access of choice in removing a small pathological focus in the pterygopalatine fossa, round foramen or lower portions of the cavernous fossa. 3. The access may be used to approach the medial portion of the infratemporal fossa. 4. The described stepwise microsurgical anatomy and internal guiding lines in the retromaxilllary space permit one to perform surgical operations with confidence. 5. With this access, there is no guidance over the great vessel (internal carotid artery). 6. The access passes through the vestibule of the mouth; in this connection its application is undesirable at surgery for intradural abnormalities.

[Skull base meningiomas spreading into the infratemporal fossa: clinical picture, diagnosis, and treatment policy]

From 1997 to 2004, the Academician N. N. Burdenko Research Institute of Neurosurgery has operated on 54 patients with intracranial meningiomas spreading into the infratemporal fossa. Fifteen patients were operated on for the first time. Thirty-nine patients had undergone surgical interventions on the average 3 times (from 2 to 8). All the patients were operated on via different orbitozygomatic approaches depending on the extent of the process. Opening the upper and lower palpebral fissures and the round foramen with resection, if required, the pterygoid processes suffice to remove tumors from the areas of the upper and lower palpebral fissures, which spread into the sphenoid and maxillary sinuses. If there are tumors at the site of the base of the anterior surface of the pyramid, and the articular bursa, it is expedient to open the oval and spinous foramens, to resect the external portions of the fundus of the middle cranial fossa and, if required, the articular process of the lower jaw. By taking into account the X-ray and histological patterns, it may be stated that invasion of meningiomas is not always accompanied by the development of hyperostosis. According to our findings, extracranial growth of meningiomas points to the invasion of osseous structures of the middle cranial fossa. Furthermore, if meningiomas grow into the infratemporal fossa, they frequently involve the muscles, nerves, and mucosa. After removing the tumors spreading to the infratemporal fossa, the optimum plastic repairs of defects of the base of the skull are as follows: hermetic closure of basal defect of the dura mater with a free fat flap, by fixing it with sutures and fibrin-thrombin glue with additional plastic repair of skull base defect with local displaced tissues on a pedicle (with a temporal muscular fascioperiosteal flap, a Bisch fat flap). Further policy of management of these patients is a complicated problem. It depends on the radicalism of an operation and the invasiveness of the process. The histobiological features of infiltrative meningiomas should be studied and this will determine management policy. Conceivably, the use of postoperative radiation therapy will be substantiated in a definite group of patients.

[A broad subfrontal access to the tumors in the base of the skull]

A total of 30 patients, aged 16 to 67, with neoplasms in the brain base and in paranasal sinuses were operated on, during 1997-2002, at Burdenko's Research Institute for Neurosurgery of the Russian Academy of Medical Sciences (RAMS). A majority of patients (21) had meningiomas. Other observations included: fibrous dysplasia of the anterior cranial fossa in 3 patients, chondroma in 2 patients, angiofibroma in 2 patients, pituitary adenoma in 1 patient and adamantinoma in 1 patient. The application of diluted subfrontal approach and of its modifications is indicated for extradural tumors located in the anterior cranial fossa and extending into the latticed main sinus of the nasopharynx. No increasing neurological symptomatology was noticed in any patients. Nasal liquor was not noted either. A seizure of an essential reduction of exophthalmos was registered in cases with crania-orbital neoplasm. It restored postoperatively in all patients with malfunctions of nasal breathing. Two patients died. The death reasons are not directly related with the approach technique. The diluted subfrontal approach is effective in extensive tumors of the anterior cranial fossa involving the latticed and main sinuses. Our experience of using the diluted subfrontal approach showed its efficiency not only in extensive extradural neoplasms but also in large meningiomas of the anterior cranial fossa extending into the latticed sinus, main bone platform, tubercle of sella turcica and into both optic canals. The discussed approach ensures essentially reduced brain traction as compared with the traditional subfrontal approach. The hermetic closure of defects formed in the brain basis is an important surgery stage involving the diluted subfrontal approach. This approach is, under modern conditions, a valuable addition to the methods, which are generally accepted in neurosurgery, and it has undoubtedly an indisputable perspective.

[Access to the anterior cranial fossa through the frontal sinus]

In 1998 to 2001, the Academician N. N. Burdenko Research Institute of Neurosurgery operated on 15 patients aged 20 to 65 years who had bulky processes in the base of the skull and paranasal sinuses by applying an access through the frontal sinus. Most patients (n = 7) had meningiomas. The others had osteoma of the base of anterior cranial fossa (n = 2), chondroma (n = 2), angiofibroma (n = 1), fibroma (n = 1), esthesioneuroepithelioma (n = 1), and neurinoma (n = 1). The main criteria for choosing this access were the site and extent of a process, the sizes of the frontal sinus, and no signs of acute or chronic rhinosinusitis. The length of frontal sinuses in the most measurement was 3.5 to 5.0 cm, their width was 7 to 10 cm. All patients showed no progression of neurological symptoms. Three patients had a decrease in visual acuity from 1.0 to 0.8; with vascular therapy, visual disorders regressed during 2 months. Olfaction became worse in 4 cases, there was anosmia in 2 cases. Nasal liquorrhea was not observed. When there were tumors in the anterior cranial fossa, an access through the anterior wall of the frontal sinus permits radical removal of both intra- and extracranial parts of a tumor with closure of the defect with a periostal flap.

[Surgery for hyperostotic cranial orbital meningiomas]

The paper analyzes surgical techniques for removal of hyperostotic cranial orbital meningiomas in 36 patients operated on in 1998 to 2000. In 19 cases hyperostosis extends to the upper and lower lid slits without involving the optic canal. It also spreads to the ethmoidal sinus in 6 cases to the frontal sinus in 3, and to the maxillary one in 2 patients. In 3 patients, hyperostosis was beyond the wing of the basic bone, by involving the temporal and frontal squamous. In 19 cases, hyperostosis was resected and the tumor was removed without creating any additional bone flaps. To make an additional basal bone flap can provide a much wider access by reducing the traction of both orbital and cerebral tissues. An orbitozygomatic flap was formed in 16 cases. To create a lateral orbital flap was sufficient to effectively eliminate hyperostosis in 3 patients. Impaired postoperative visual acuity was observed in 5 patients undergone resection for the hyperostotic optic canal, in 2 patients of them there was a decrease in visual acuity from 1.0 to 0.1 and in 1 patient it reduced from 1.0 to 0.2. A year later, visual acuity in these patients increased up to 0.5-0.8. After resection of the hyperostotic optic canal, blindness occurred in 2 patients, in one of them, photoperception appeared on day 5 after surgery and 3 months later visual acuity restored up to 0.6. Thus, the use of high-speed drill and the creation of an orbital or orbitozygomatic flap can increase the efficiency of removal of hyperostotic cranial orbital meningiomas.

[Disseminated craniofacial chondrosarcoma]

Chondrosarcomas are malignant mesenchymal tumors of chondroid nature. Less than 5% of all chondrosarcomas are localized in the head and neck. The paper analyzes a case of extensive chondrosarcoma of the skill base, which involves the anterior and median cranial fossa, ethmoidal, sphenoidal, right maxillary sinuses, and intratemporal fossa. A basal approach that is a combination of two-flapped subfrontal and orbitozygomatous accesses was used to remove the tumor. In doing so, the tumor could be excised and extensive defects of the skull base could be effectively closed with the flaps of the periostium and musculus temporalis, yielding a good functional and cosmetic effect.

[Cementoma of the skull base]

Cementomas result from the odontotic epithelial-mesenchymal complex and are located mainly in the area of large and small molar teeth of the mandible. There was an extremely rare cement location in the analyzed clinical cases. In the first case, cementoma of the frontal sinus spread into the ethmoidal sinus and eye socket in a female patient aged 38 years. The tumor is manifested by right frontalorbital pain and exophthalmos. There were no problems in removing the tumor and repairing the defect of the skull base. The second case was an extensive tumor in a 11-year-old child, which involves the maxillary, ethmoidal, and sphenoidal sinuses, by damaging the bones of the skull base. Tumor removal gave rise to an extensive defect of the skull base which the dura mater protruded through. In this case the important stage was closure of the defect of the dura mater and that of the skull base with the dura mater protruding through. This defect could be successfully closed with a pedicle musculoperiosteal flap of the musculus temporalis by fixation with sutures and fibrinthrombin glue.

[Plastic repair of a defect in the base of the skull with soft tissues from the orbit after the removal of an extensive esthesioneuroepithelioma]

The paper describes a clinical observation of closure of sphenoidal sinus defect and plastic repair of dura mater by using orbital tissues after removal of a tumor from the medial portions of the middle cranial fossa, which spread into the orbit and sphenoidal sinus, in complete irreversible loss of visual function, ophthalmoplegia and ptosis in a patient with skull soft tissue hypotrophy due to multiple operations and radiation therapy and hence unsuitable for displacement and closure. This observation shows it possible to use orbital soft tissue for repair of the base of the skull, in cases when integumentary cranial tissues are impossible to use as a plastic material due to their hypotrophicity. At the same time severe dysfunctions, such as blindness and ophthalmoplegia enable orbital tissues to be employed without significantly deteriorating any functional and cosmetic effect.

[Surgery of the base of the skull]

To treat pathological processes, primarily tumors, in the base of the skull is one of the most intricate neurosurgical problems. In the past decade, interest in this problem has greatly increased due to the advent of new methods of diagnosis, up-to-date neurosurgical equipment and to a greater cooperation of physicians of related disciplines: ophthalmologists, otosurgeons, plastic surgeons. The authors present and summarize the experience accumulated by the researchers of the N. N. Burdenko Institute of Neurosurgery in the past 10 years in treating basal tumors. Based on a great deal of clinical findings, approaches are proposed in treating some groups of basal tumors, such and pituitary adenomas, craniopharyngiomas, meningiomas at various sites, trigeminal and acoustic neurinomas, and malignant neoplasms of the base of the skull. The conditions required for successful surgical treatment of the processes in the base of the skull are described in detail. One of them is a correct determination of a surgical approach.

[The use of the temporal muscle for closing postoperative wounds]

The correct use of the musculus temporalis may close rather extensive defects of the base of the skull, yielding good functional and cosmetic results. For plastic purposes, the following types of a graft of the musculus temporalis are applied: 1) a simple interpolated graft; 2) a split-thickness interpolated graft; and 3) a free graft (by crossing the tendon of the musculus temporalis, which allows the muscle to be additionally displaced) for closure of defects after removal of tumors from the socket, maxillary, sphenoidal sinuses, infratemporal fossa, the bases of the middle cranial fossa, for plastic repair of the hard palate, for closure a defect after transpyramidal access (mastoidectomy) and for the treatment of ankylosis of the mandibular joint. Axial grafts may be used to repair the scalp and supercilia.

[Variants in the growth of meningiomas of the base of the skull spreading into the orbit and paranasal sinuses]

Meningiomas of the skull base involving the orbit and paranasal sinuses were diagnosed in 254 patients. The patients were operated on in 1982-1991. All craniocephalic meningiomas involve the anterior skull base bones. The involvement presents either as destruction (nodular tumor) or as hyperostosis (infiltrative growth of the tumor). All patients were divided into 8 groups with different location of skull bones involvement. A classification of meningiomas of skull base disseminating into the orbit and paranasal sinuses is proposed, proceeding from the anatomical principle. This classification helps plan a surgical access, scope of intervention, probable size of skull defect and method of its closure, possible postoperative functional and cosmetic defects.

[An approach to an esthesioneuroblastoma of the anterior cranial fossa via the anterior wall of the hypertrophied frontal sinus]

A 40-year-old patient with anterior cranial fossa esthesioblastoma was operated on. Surgical approach via anterior wall of enlarged frontal sinus was used. After removal of tumor from anterior cranial fossa, ethmoidal and frontal sinuses, skull base defect was closed with abdominal fat and periosteum. Different approaches to anterior cranial fossa are discussed.