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Mikhail F Chernov

Publications and source records attributed to Mikhail F Chernov.

10 recordsLinked to original sources
PubMed2005

Scaled suction for microneurosurgery: technical note.

OBJECTIVE: We have developed scaled suction to facilitate the measurement of aneurysm neck width and tumor size during operations. METHODS: We constructed a new suction device scaled every 1 mm from the tip to 3 cm and every 5 mm from 3 to 5 cm. The scaled suction devices have been used in 50 aneurysm and brain tumor operations. RESULTS: The new suction device permits easy measurement of aneurysm neck width, tumor size, the extent of internal decompression of tumor, and depth from the surface of the brain to the lesion. CONCLUSION: Our scaled suction device is a simple and useful navigator for continuously measuring intraoperative variables such as lesion size and distance between the lesion and the surrounding vital structures.

Aneurysm↗
PubMed2005

Reduction of blood flow in the brain stem and cerebellum caused by petroclival tumors.

Blood flow in the brain stem (BSBF) and cerebellum (CerBF) was investigated by positron emission tomography in 12 patients with petroclival tumors (study group) and 14 healthy volunteers (control group). (15)O-labeled water was used as the radioisotope tracer. BSBF and ipsilateral CerBF were significantly lower in the study group compared with the control group (p < 0.005). Five of 12 patients in the study group exhibited more than 20% reduction of CerBF ipsilateral to the tumor, whereas no such asymmetry was disclosed in any subject in the control group (p < 0.01). Sex, age, and tumor histology had no statistically significant association with the level of BSBF. Ipsilateral CerBF was significantly lower in patients with vestibular schwannomas, compared to those with sphenopetroclival meningiomas (p < 0.025). No statistically significant association between BSBF and the type of postoperative course was found, whereas four of the five patients with more than 20% reduction of CerBF ipsilateral to the tumor had prominently increased cerebellar ataxia after removal of the neoplasm. Preoperative investigation of the cerebral blood flow may be important for the prediction of outcome after surgical resection of petroclival tumors.

Adult↗
PubMed2005

Neurofiberscope-guided management of slit-ventricle syndrome due to shunt placement.

OBJECT: The purpose of this study was to evaluate an original neurofiberscope-guided strategy for the management of slit-ventricle syndrome that occurs after shunt placement. METHODS: Between 1995 and 2003 15 patients with slit-ventricle syndrome (mean age 14.2 years) underwent endoscopic third ventriculostomy (ETV) and shunt removal. During the initial surgical procedure a neurofiberscope with a small outer diameter was inserted along the shunt tube into the collapsed ventricle for endoscopically controlled removal of the ventricular catheter and evaluation of brain compliance. If the latter was sufficiently preserved, primary ETV and shunt removal were performed (four cases). If brain compliance seemed to be significantly reduced, endoscopically controlled replacement of the ventricular catheter and implantation of the Codman-Hakim programmable valve shunt device were performed (11 cases). In these patients, delayed ETV and shunt removal were performed later (mean period of 16.3 months). No medical or surgical complications occurred in any case. Follow up ranged from 6 to 84 months (mean 31.1 months; median 22 months). All patients became shunt independent and 13 became symptom free. Overall, the size of the ventricles returned to normal in five cases, became slightly dilated in nine, and moderately dilated in one. CONCLUSIONS: Neurofiberscope-guided treatment of slit-ventricle syndrome involving shunt removal and ETV appears to be beneficial; all patients in this series were symptom free and shunt independent at the end of follow up.

Adolescent↗
PubMed2004

Proton MRS of the peritumoral brain.

Long-echo (TR: 2000 ms, TE: 136 ms) proton MRS of the cerebral tissue in the vicinity to intracranial lesion was done in 15 patients, mainly with parenchymal brain tumors. Significant decrease of N-acetylaspartate (NAA) (P<0.001) and more frequent presence of lactate (P<0.01) comparing with distant normal white matter were found in the perilesional brain tissue. The level of NAA in the perilesional brain tissue had negative associations with presence of lactate in the lesion (P<0.05), excess of lactate in the lesion compared to perilesional brain (P<0.01), grade of the perilesional edema (P<0.01) and patient's age (P<0.05). Multivariate analysis disclosed that identification of lactate in the lesion is associated with lower relative NAA content in the perilesional brain tissue, independently on the presence or absence of any other factor, including brain edema (P<0.001). In patients with lobar lesions who had at least one epileptic seizure during course of their disease the relative NAA content in the perilesional brain was significantly lower, comparing with those who were seizure-free (P<0.05). Therefore, lactate diffused from the tumor, or other metabolites secreted by lactate-producing neoplasm, should be considered as important contributors to the neuronal dysfunction in the surrounding brain. Decrease of NAA in the vicinity to intracranial lesions may reflect neuronal alteration responsible for associated epilepsy.

Adult↗
PubMed2004

Early metabolic changes in metastatic brain tumors after Gamma Knife radiosurgery: 1H-MRS study.

Evaluation of early metabolic changes in metastatic brain tumors after Gamma Knife radiosurgery was performed by long-echo (TR, 2000ms; TE, 136ms; 128-236 acquisitions) volume-selected single-voxel proton magnetic resonance spectroscopy (MRS). Eighty-five brain metastases in 81 patients were investigated before treatment and 16-18h thereafter. Standard metabolic ratios, namely N-acetylaspartate (NAA)/creatine (Cr), phosphorylcholine/glycerophosphorylcholine (Cho)/Cr, NAA/Cho, lactate (Lac)/Cr, and mobile lipids (Lip)/Cr, were calculated, and comparison of their values before and after irradiation was done. No volumetric changes of any neoplasm were found in any case on the next day after treatment. At the same time, significant reduction of Cho/Cr (P < 0.001) and NAA/Cr (P < 0.01) ratios on the proton MRS of the tumor was disclosed. Reduction of Cho/Cr ratio was significantly more prominent in neoplasms with higher pretreatment Cho/Cr ratios (P < 0.001) and heterogeneous contrast enhancement (P < 0.01). Reduction of NAA/Cr ratio was predominantly determined by its pretreatment value (P < 0.001). The observed decrease of Cho/Cr ratio probably reflects inhibition of proliferative activity and early apoptotic cell loss, whereas reduction of NAA/Cr may result from radiation-induced modulation of neuronal activity in the peritumoral brain tissue. Serial proton MRS represents a valuable diagnostic tool for evaluation of metabolic changes in intracranial neoplasms after radiosurgical treatment.

Aged↗
PubMed2004

Double-endoscopic approach for management of convexity arachnoid cyst: case report.

BACKGROUND: Controversy exists about the best treatment modality for arachnoid cysts. Widely accepted neurosurgical options include craniotomy with open resection of the cyst walls, shunting procedures and stereotactic fenestration of the cyst cavity. Recently, neuroendoscopic approach showed its effectiveness for treatment of these lesions. CASE DESCRIPTION: In the presented case the large convexity arachnoid cyst was diagnosed in a 22-year-old woman with head dullness and local bone bulging. No neurologic signs were found. Surgery was performed by double-neuroendoscopic approach with simultaneous use of two flexible ventriculofiberscopes, which permitted wide resection of the inner cyst wall. Complete resolution of symptoms was noted soon after surgery. CONCLUSION: Double-endoscopic approach might be useful for complex neuroendoscopic procedures that need different simultaneous surgical actions, particularly for cases of large arachnoid cysts.

Adult↗
PubMed2004

Complete recovery of visual functions after multimodality treatment for intrinsic chiasmatic-hypothalamic astrocytoma--case report.

A 21-year-old female was admitted with complaints of severe impairment of vision. The visual acuity was 0.02 in both eyes along with residual visual fields and central scotomas. Neuroimaging disclosed a chiasmatic-hypothalamic glioma. Surgery was performed with partial removal of the intrachiasmatic part of the intrinsic tumor. The histological diagnosis was fibrillary astrocytoma. Progressive recovery of vision began in the first week after surgery. Adjuvant treatment included one course of fractionated radiation therapy and six courses of chemotherapy. Complete recovery of visual acuity occurred after 10 months, and the visual fields were restored after an additional 6 months. Her vision has been stable during 2 years of follow up. The prognosis for recovery of vision after treatment of optic pathway gliomas mainly depends on the severity of visual loss at admission and is negatively influenced by intrinsic tumor growth, symmetrical extension, and involvement of the chiasm. Despite the presence of all these factors in the present case, multimodality management resulted in the complete recovery of visual functions. Surgery may be indicated in cases of intrinsic chiasmatic gliomas complicated by severe visual loss.

Adult↗