Gökhan Akdemir

Neuroprotective effects of propofol following global cerebral ischemia in rats

Abstract. Propofol has cerebral vascular and metabolic effects similar to those of barbiturates, and it is used to maintain neurosurgical anesthesia because it reduces cerebral metabolic rate, cerebral blood flow, and intracranial pressure. Although the use of propofol as a cerebral protectant during certain neurosurgical procedures has been advocated, consensus has not been reached as to a protective effect of propofol on cerebral ischemia. In this study we observed the neuroprotective effects of propofol during global cerebral ischemia-reperfusion injury by the use of four-vessel occlusion method in a rat model. We measured the levels of malondialdehyde as a marker of lipid peroxidation in ischemic tissue, and the results indicate that propofol plays a role in the inhibition of neuronal death induced by brain ischemia.

Prognostic value of serum neuron-specific enolase levels after head injury

Neuron-specific enolase (NSE) is a dimeric cytoplasmic enzyme detected in high levels in neurons and acts in the glycolytic pathway. It is known that there is a quantitative relationship between the concentration of serum NSE and the degree of cell damage in the central nervous system. We examined serum levels of NSE by enzyme immunoassay in 89 patients with head injury and aimed to evaluate its relationship with neurological status and prognosis of the patients.

Surgical management of syringomyelia–Chiari complex

Abstract Great variety exists in the indications and techniques recommended for the surgical treatment of syringomyelia–Chiari complex. More recently, magnetic resonance (MR) imaging has increased the frequency of diagnosis of this pathology and offered a unique opportunity to visualize cavities inside the spinal cord as well as their relationship to the cranio-cervical junction. This report presents 18 consecutive adult symptomatic syringomyelia patients with Chiari malformation who underwent foramen magnum decompression and syringosubarachnoid shunting. The principal indication for the surgery was significant progressive neurological deterioration. All patients underwent preoperative and postoperative MRI scans and were studied clinically and radiologically to assess the changes in the syrinx and their neurological picture after surgical intervention. All patients have been followed up for at least 36 months. No operative mortality was encountered; 88.9% of the patients showed improvement of neurological deficits together with radiological improvement and 11.1% of them revealed collapse of the syrinx cavity but no change in neurological status. None of the patients showed further deterioration of neurological function. The experience obtained from this study demonstrates that foramen magnum decompression to free the cerebro-spinal fluid (CSF) pathways combined with a syringosubarachnoid shunt performed at the same operation succeeds in effectively decompressing the syrinx cavity, and follow-up MR images reveal that this collapse is maintained. In view of these facts, we strongly recommend this technique, which seems to be the most rational surgical procedure in the treatment of syringomyelia– Chiari complex.

Therapeutic efficacy of intraventricular cyclosporine A and methylprednisolone on a global cerebral ischemia model in rats

Abstract Objective: Cyclosporine A (CsA) with its immunosuppressive actions and methylprednisolone (MP) as a free radical scavenger were suggested together to alleviate neural tissue damage after an ischemic insult. The aim of this study was to investigate neuroprotective properties of CsA and MP in a global cerebral ischemia model. Methods: Twenty-eight male Sprague–Dawley rats were divided randomly into four separate groups: CsA, MP, sham and control. Global cerebral ischemia was performed with the four-vessel occlusion model. After 30 minutes of ischemia, reperfusion was started with concomitant intraventricular administration of saline, MP (20 mg/kg) and CsA (10 mg/kg) into the lateral ventricle. Lipid peroxidation levels were measured from all experimental groups. Rats subjected to global cerebral ischemia exhibited a significant increase in cerebral lipid peroxide levels 6 hours after the onset of reperfusion. Both CsA and MP treatment significantly attenuated the degree of lipid peroxidation in cerebral tissues (p<0.05). Histopathological examinations of the CA1 sector of the hippocampus verified the neuroprotective properties of MP and CsA. Conclusions: The results suggested the neuroprotective properties of both agents, emphasizing more potent protection against ischemia by CsA. It was proposed that CsA could have exerted this effect with the blockage of mitochondrial permeability transition (MPT) pores, which are also critical if the necrotic and apoptotic cascades of the cell are considered. MP is judged to be neuroprotective, particularly in terms of its effects on lipid peroxidation. In conclusion, CsA and MP are ascertained to be neuroprotective agents as long as they cross the blood–brain barrier.

Intraventricular atrial natriuretic peptide for acute intracranial hypertension.

The effect of intraventricular atrial natriuretic peptide (ANP) on elevated intracranial pressure (ICP) was evaluated in a rodent model of global ischemia and reperfusion. ANP administration into the lateral ventricle 30 minutes after reperfusion statistically significantly reduced ICP compared with both vehicle treated animals (p < 0.001) and pretreatment pressures (p < 0.001). The ICP effects of ANP did not coincide with specific changes in regional perfusion parameters measured by laser-Doppler flowmetry. Two different vehicles for ANP were used to verify that the changes in ICP observed were independent of the sodium content administered in the vehicle. Based on the reductions observed in ICP, ANP deserves further evaluation as a treatment modality for the acute elevations in ICP associated with ischemic brain injury.

Cervical laminar exostosis in multiple hereditary osteochondromatosis: anterior stabilization and fusion technique for preventing instability

Multiple hereditary osteochondromatosis is a genetically transmitted disorder consisting of multiple projections of bone capped by cartilage, which are called exosloses. Spinal cord compression due to expansion of a laminar osteochondroma is rare but well recognized. Surgical decompression usually improves the patients neurological status but, in cervical exostosis, postlaminectomy kyphosis and instability problems, especially in the high-risk adolescent group, form the most significant potential difficulties in the postoperative period. We report a case of cervical laminar exostosis that was treated by anterior stabilization and fusion and discuss the benefits of this technique.

Lateral Orbitotomy Approach to Orbital Tumors: Report of 10 Cases

AIM Lateral orbitotomy is a well-known approach for lesions of the lateral orbital cone. It is still appropriate for laterally situated tumors although contemporary cranial base approaches were defined and developed within the last decades. MATERIAL AND METHODS Here we report 10 orbital lesions operated with lateral orbitotomy, nine of which were extraconal. Cholesterol granuloma, arachnoid cyst, pleomorphic adenoma, malign epithelial tumor, dermoid cyst, inflammatory granuloma and cavernoma were the pathologies encountered. RESULTS The extent of lateral orbitotomy should depend on the size, consistency and nature of the lesion for easy removal and less bony resection. In this regard, contrast enhanced CT scans give useful information for operative strategy. The success of surgery can be improved and cosmetic problems can be minimized if meticulous care is taken during orbital rim resection. CONCLUSION Although there is a wide range of histopathological diagnosis for orbital tumors, lateral orbitotomy is a safe approach, particularly if the lesions are extraconal.

Cranio-cerebral erosion: delayed diagnosis and treatment.

Cranio-cerebral erosion is a well-known complication of calvarian fracture with underlying dural tear and cerebral injury in infancy and early childhood. The anatomy, pathogenesis and natural evolution of these lesions remain obscure. The common clinical symptoms are seizures, focal neurological deficits, impairment of consciousness and a soft subgaleal mass. Three patients of cranio-cerebral erosion who underwent delayed surgery in their adult lives are presented to illustrate the common and uncommon features, and their long-term outcome is discussed.

Thyrotropin secreting pituitary adenoma accompanying a silent somatotropinoma.

Thyroid stimulating hormone (TSH) secreting pituitary adenomas are rare tumors manifested as hyperthyroidism with goiter in the presence of elevated TSH. We present a case with pituitary adenoma secreting both TSH and growth hormone (GH) with the prominent clinical findings of hyperthyroidism but without clinical findings of acromegaly. Pituitary magnetic resonance imaging revealed a macroadenoma. Transsphenoidal surgery was performed twice. The immunohistochemical staining showed that tumor cells were strongly reactive to GH and relatively mildly reactive to TSH. Control pituitary imaging revealed a residual macroadenoma, and long acting octreotide treatment was administered. After two years of the treatment, tumor size remained the same while thyroid function tests and insulin-like growth factor 1 (IGF-I) values returned to normal ranges. In conclusion, we always recommend hormonal examinations for all patients who have pituitary adenoma without signs and symptoms of acromegaly.

Intracranial giant tuberculoma mimicking brain tumor: a case report.

Tuberculomas are small tumor-like lumps that can be seen, usually in large numbers, in central nervous system involvement of tuberculosis. Giant tuberculomas that are big enough to cause symptoms of compression are also encountered, though rarely. When they are really large, tuberculomas may result in increased intracranial compression, neurologic deficits, or epileptic attacks. Giant tuberculomas may be confused with brain tumors on cranial magnetic resonance imaging. Cranial magnetic resonance imaging and histopathology examinations are used for diagnosis. Although magnetic resonance imaging is useful for diagnosing tuberculoma, histopathology examination is the gold standard for a final diagnosis. This paper presents a case involving a 66-year-old patient who complained of headache, imbalance and dizziness, and underwent an operation in the neurosurgery clinic with a pre-diagnosis of brain tumor, and was then diagnosed with intracranial giant tuberculoma.