Neurosurgery

Objective Nitric oxide synthesized from L-arginine via the nitric oxide synthase enzyme family is the main regulatory molecule in many physiological systems. The level of nitric oxide can now be measured in tissues by a direct real-time amperometric method. The effect of electrical stimulation of the upper cervical spine on the arteries that supply the brain and upper extremities has been established by experimental studies, and thus it has begun to be used in clinical practice to increase blood flow in the brain and the peripheral vascular system. The mechanism of this effect is still a subject of research. This is the first report of real-time nitric oxide measurement in living brain and dermal tissue during electrical stimulation of the upper cervical spine. Methods Using the amperometric method, nitric oxide levels in frontal subcortical and front foot skin were measured before, during and after electrical stimulation of the upper cervical spine in three groups of rabbits that received infusions of saline solution, 7-aminoguanidine or atropine. Results By electrical stimulation, tissue nitric oxide levels increased significantly and remained increased during stimulation in the brain and skin. The nitric oxide levels dropped back to normal value 1 min after stimulation was turned off. Conclusion The results we obtained have showed that realtime nitric oxide could also be measured by an amperometric method in living tissues like brain. The effect of stimulation on nitric oxide levels of living tissues disappears immediately when the stimulation is turned off.

Background. The exact aetiology, growth and rupture of intracranial aneurysms is unclear. In this study we investigated a possible association between intracranial aneurysm rupture and polymorphism of the endothelial nitric oxide synthase gene G894T.

Purpose To investigate the effect of an anti-TNF-a agent (etanercept) on recovery processes in a partial spinal cord injury (SCI) model using clinical and electrophysiological tests. Methods Twenty-four New Zealand rabbits were divided into three groups: group 1 [SCI ? 2 mL saline intramuscular (i.m.), n = 8], group 2 (SCI ? 2.5 mg/kg etanercept, i.m., 2-4 h after SCI, n = 8) and group 3 (SCI ? 2.5 mg/kg etanercept, i.m., 12-24 h after SCI, n = 8). Rabbits were evaluated before SCI, immediately after SCI, 1 week after, and 2 weeks after SCI, clinically by Tarlov scale and electrophysiologically by SEP. Results Tarlov scores of groups 2 and 3 were significantly better than group 1, 2 weeks after SCI. SEP recovery was significantly better in groups 2 and 3 than group 1, 2 weeks after SCI. Conclusions These results show that blocking TNF-a mediated inflammation pathway by an anti-TNF-a agent enhances clinical and electrophysiological recovery processes in partial SCI model.

Aim: The effect of short term intracisternal and intracarotid L-arginine infusion on experimental cerebral acute phase vasospasm in a rabbit subarachnoid haemorrhage model is investigated, and the two groups compared. Materials and Method: Subarachnoid haemorrhage was produced by intracisternal injection of autologous blood in New Zealand rabbits. On the fourth day after subarachnoid haemorrhage, cerebral blood flow was monitored using transcranial Doppler ultrasonography during intracisternal and intracarotid saline and L-arginine infusions. Result: Cerebral blood flow measurements revealed resolution of vasospasm with short-term intracisternal and intracarotid L-arginine infusion. No significant difference was found between the effects of intracisternal and intracarotid L-arginine infusions, however intracarotid L-arginine infusion created a more potent vasodilatation towards the end of infusion. Conclusion: Both intracisternal and intracarotid short term L-arginine infusion significantly improve acute phase cerebral vasospasm after experimental subarachnoid haemorrhage. Intracarotid L-arginine infusion is more potent and safer as large amounts of intracisternal L-arginine may lead to overproduction of nitric oxide by inducible nitric oxide synthase with the production of free radicals.

Background: The genetic risk factors that contribute to the risk of developing abdominal aortic aneurysm (AAA) are poorly understood. We assessed the association of endothelial nitric oxide synthase (eNOS) gene polymorphism with AAA. Methods: eNOS gene polymorphism of 61 patients with AAA and 62 control participants were analyzed by polymerase chain reaction (PCR)-restriction technique. Results: eNOS G894 homozygote T/T genotype polymorphism and 894T allele frequency in patients with AAA were significantly higher than those of the control participants (P ¼ .01, P ¼ .03). Among patients with AAA, the eNOS G894 T/T polymorphism and 894T allele frequency were associated with larger AAAs. Conclusion: The current study, in a small group of participants, showed a relationship between eNOS G894T polymorphism and AAA.

Introduction. Panic disorder (PD) and major depressive disorders (MDD) are serious mental disorders but the mechanisms underlying the pathophysiology are poorly understood. Nitric oxide (NO) is a gas considered to play an important role in mediating anxiety and stress response and is synthesised from nitric oxide synthase (NOS). The endothelial isoform (eNOS) has been found also in platelets. Homocysteine (Hcy) is an amino acid which naturally occurs in the human body. Elevated levels are linked to increased risk of cardiovascular, neurological and psychiatric diseases. In this study we aimed to evaluate NO, platelet aggregation and Hcy levels in PD and MDD patients. Materials and methods. Nineteen PD and 18 MDD patients participated in this study. NO levels were measured spectrophotometrically, platelet aggregation levels were measured in an aggregometer and Hcy levels were measured by HPLC. Results. NO levels were signifi cantly lower in patients with MDD and PD than in control subjects ( P Ͻ 0.05). Hcy and platelet aggregation levels were signifi cantly higher in patients with MDD and PD than in control subjects ( P Ͻ 0.05). Conclusion. Further more detailed studies are needed to fi nd out the effects of drugs on these parameters or to disclose the exact mechanism underlying the alteration of these parameters.

Çocukluk çağının ikinci en sık ölüm nedeni kafa travması sonrası gelişen ağır beyin hasarlarıdır. Dört yaş altı çocuklar çocukluk çağı kafa travmasında en yüksek risk grubunu oluşturur. Kafa kemiklerinin tam gelişmemiş olması delici-kesici beyin dokusu yaralanmaları için kolaylaştırıcı bir durumdur. Elinde oyuncağı olduğu halde yüksekten düşme sonrası elindeki oyuncağın sebep olduğu delici-kesici beyin dokusu yaralanması ile acile başvuran ve ameliyat edilerek sorunsuz bir şekilde taburcu edilen 18 aylık kız çocuğu olgusu sunulmuş ve literatür bilgileri ile birlikte tartışılmıştır.

Amaç. Nitrik Oksit (NO) sentezi, 3 izoformu bulunan nitrik oksit sentaz enzimi tarafından düzenlenmektedir. Bunlar Endotelyal Nitrik Oksit Sentaz (eNOS), nöronal nitrik oksit sentaz (nNOS) ve indüklenebilir nitrik oksit sentaz (iNOS). ENOS, arter damar çapını düzenlemektedir, İşlevsel etkinliği dışında yapısal etkinliği de tespit edilmiştir. Bu çalışmada eNOS genindeki iki polimorfizmle bir yapısal damar patolojisi olan kanamış kafa içi anevrizma varlığı arasındaki ilişki araştırıldı. Yöntem. Kanamış kafa içi anevrizması olan 43 hasta ve 46 sağlıklı bireyin DNA'larında eNOS geni intron 4 (27 baz çifti tekrarı) ve promoter T786C polimorfizmi jel elektroforez ve dizileme tekniği ile incelendi. Bulgular. CC homozigot genotip varlığı kanamış kafa içi anevrizması olan hasta grubunda anlamlı olarak yüksek olarak tespit edilmiştir (p<0,05). Hasta ve kontrol grupları arasında intron 4 (27 baz çifti tekrarı) açısından anlamlı fark tespit edilememiştir (p>0,05). Sonuç. Homozigot T786C genotip varlığı çalışmaya aldığımız yöresel hasta grubunda kanamış kafa içi anevrizma varlığı açısından risk sebebi olarak görülmektedir. İntron 4 (27 baz çifti tekrarı) polimorfizminin varlığı ise risk teşkil etmemektedir.

We present a case of 45 years old female patient with two primary cerebral hydatid cysts, each localised in separate hemispheres. Detailed studies revealed no evidence of hydatid disease elsewhere in the body. The cysts were removed by two separate operations. Though the cyst in the right posterior parietal lobe was delivered unruptured, seven months later a new cyst was detected in the same cavity, which seems to show relatively rapid growth in a year, and was also removed unruptured. This case is presented here for its unusual features such as having two primary cerebral hydatid cysts simultaneously in separate hemispheres, one of which partly localised intraventricularly, and the occurrence of a new cyst in the same cavity following intact removal of the previous cyst.

The cerebral vessels have sympathetic, parasympathetic, and sensory innervations. A sensory innervation of the cerebral vessels originating in the trigeminal ganglion has been described in a number of species by several investigations. It has been shown that the electrical stimulation of the trigeminal ganglion causes an increase of cerebral blood flow (CBF). The aim of our present study is to stimulate the trigeminal ganglion with an extracranial and non-invasive method. A stimulating electrode was put in the nasal mucosa via right nares of rabbits and trigeminal ganglion was stimulated orthodromically via nasociliary nerve (NCN). Variations in the cortical CBF were evaluated by laser Doppler flowmetry. In experiment group, CBF increased together with the beginning of electrical stimulation. The flow values were remained high as long as the stimulation. In post-stimulation period, the CBF was decreased gradually and returned to the baseline values at 120 s. This study demonstrated that the electrical stimulation of the NCN branch of the trigeminal nerve increases the cortical CBF under physiological conditions.

Fibrous dysplasia (FD) is an uncommon benign disorder of unknown etiology. It most likely represents a disorder of normal bone development. The disease can involve any bone in the body. In the head and neck, the skull and facial bones are involved in 10-25% of cases of monostotic FD. Involvement of the clivus in monostotic FD is extremely unusual, and has rarely been reported previously. The diagnosis is based on radiological images. We retrospectively reviewed our database and identified three patients with the diagnosis of FD of the clivus. We reviewed the clinical and radiological findings of these patients in this paper.

Background. The exact aetiology, growth and rupture of intracranial aneurysms is unclear. In this study we investigated a possible association between intracranial aneurysm rupture and polymorphism of the endothelial nitric oxide synthase gene G894T. Methods. Endothelial nitric oxide synthase gene polymorphism of 53 patients with ruptured intracranial aneurysms and 60 control subjects were analysed by the polymerase chain reaction-restriction fragment length polymorphism technique. The genotype distribution and allele frequencies of endothelial nitric oxide synthase gene polymorphism in patients with ruptured intracranial aneurysm and healthy subjects were compared. Findings. The homozygous (TT) genotype frequency was significantly higher in patients with ruptured intracranial aneurysms. It was also found that the presence of eNOS 894TT genotype was significantly associated with the risk of intracranial aneurysm rupture (p&lt;0.05). Conclusion. Polymorphism in exon 7 of the endothel...

We report a case of multilevel thoracic spinal epidural abscess without any evidence of predisposing factors. Methicillin-susceptible Staphylococcus aureus was identified as the causal pathogen. Infection was managed with surgical debridement and a prolonged course of antibiotic therapy.

Fibrous dysplasia (FD) is an uncommon benign disorder of unknown etiology. It most likely represents a disorder of normal bone development. The disease can involve any bone in the body. In the head and neck, the skull and facial bones are involved in 10–25% of cases of monostotic FD. Involvement of the clivus in monostotic FD is extremely unusual, and has rarely been reported previously. The diagnosis is based on radiological images. We retrospectively reviewed our database and identified three patients with the diagnosis of FD of the clivus. We reviewed the clinical and radiological findings of these patients in this paper.

Burr-hole irrigation and burr-hole drainage without irrigation are the most popular methods for treatment of chronic subdural haematoma. It is not well known if irrigation is necessary or which method has a higher recurrence rate. We compared the recurrence rates of those two methods. Forty-two patients were treated by burr-hole irrigation (irrigation group), whereas 38 patients were treated by burr-hole drainage (drainage group). Recurrence rate and its relation with sex, age, haematoma localization and aetiology were investigated in both groups. There was no significant difference between recurrence rates of the two groups. There was also no correlation between recurrence rate and age, sex, haematoma localization, or aetiology. There was no significant difference between recurrence rates of the two groups. Since the burr-hole drainage method is simpler to carry out, its use may be preferable.

Background. Recent studies on the pathogenesis of cerebral vasospasm following subarachnoid haemorrhage (SAH) suggest a breakdown of the balance between the vasoconstrictor and vasodilator systems. A shortage of a major cerebral vasodilator, nitric oxide (NO), has been accused of causing this breakdown. We investigated the e¨ect of continuous intracisternal infusion of a NO precursor, L-Arginine, in a rabbit SAH model. Method. Three experimental groups were designated: Group 1 ± Cerebral blood¯ow (CBF) data was obtained via transorbital Doppler ultrasonography (TDU) in 8 normal rabbits. Group 2 ± Intracisternal catheter placement and TDU study during saline infusion were performed in 8 animals at the 4 th day of SAH, Group 3 ± SAH occurred in 8 animals. 4 days later, L-Arginine was infused intracisternally for 1 hour, while TDU was performed before and during infusion. CBF parameters which were obtained via TDU measurement or calculations, were compared. Findings. The results of TDU revealed signi®cant vasospasm in all SAH animals, as well as resolution of vasospasm with L-Arginine infusion. After 20 minutes of infusion, a steady and sustained vasodilation was obtained in the third group. The analysis of CBF data revealed a signi®cant di¨erence in SAH values, and no di¨erence in control animals. Interpretation. Our results support the contribution of the``NO shortage'' concept in the pathogenesis of cerebral vasospasm and overconsumption of L-Arginine during the post-SAH period may cause this shortage. L-Arginine treatment may be useful for the prophylaxis and treatment of cerebral vasospasm. The intracisternal infusion method can eliminate the short action time disadvantage of L-Arginine.