The Effect of Early Myelotomy on Glutamate Concentrations in Spinal Cord Injury Rat Model.

AIM: To evaluate the effect of early myelotomy on glutamate concentrations in injured spinal cord tissue with a weight drop spinal cord injury rat model. MATERIAL AND METHODS: The rats were assigned randomly to one of four groups, as follows: in group I, rats underwent laminectomy; group II, myelotomy was performed after laminectomy; group III, rats received contusion after laminectomy; and group IV, myelotomy was performed 1 hour after laminectomy and contusion. In order to create a spinal cord injury, a 10-g rod was dropped from a height of 50 mm onto the exposed dura at T10 level. For the myelotomy procedure, a longitudinal 1-1.5 mm depth midline incision was made to the spinal cord. Twelve hours later, rats were decapitated, and the spinal cord tissues were removed. The obtained tissues' glutamate concentrations were measured using the HPLC technique. RESULTS: The glutamate levels were significantly lower in group III than those of groups I and II. In group IV, glutamate levels were significantly high compared to group III and significantly low compared to group I. Between groups I and II, there was no statistically significant difference. CONCLUSION: This study's results suggest that early myelotomy significantly prevented glutamate depletion from the injured spinal cord. Compared to the normal spinal cord, there was still significant depletion in injured spinal cord with myelotomy because of the initial glutamate release until the myelotomy was performed. It was also concluded that myelotomy was not harmful to the spinal cord as it did not cause significant glutamate depletion.

The Evaluation of Glutathione Reductase and Malondialdehyde Levels in Patients With Lumbar Disc Degeneration Disease.

BACKGROUND/AIM: Increased oxidative stress plays a crucial role in pathogenesis of various diseases. The present study aims to investigate glutathione reductase (GR) and malondialdehyde (MDA) enzymes as markers of oxidative stress mechanisms in lumbar disc degeneration disease (LDDD). PATIENTS AND METHODS: The study group consisted of 39 patients diagnosed with LDD and 37 healthy individuals in the control group. The enzyme-linked immunosorbent assay (ELISA) method was used to determine serum GR and MDA levels in the two study groups. RESULTS: Serum GR levels were significantly lower (p=0.008), while MDA levels were significantly higher in the patient group compared to the controls (p=0.025). CONCLUSION: Oxidative stress mechanisms play a crucial role in disc degeneration and GR deficiency could be an eligible risk factor for LDDD.

Difficulties of Distal Catheter Insertion of Ventriculoatrial Shunting in Infants and Little Children.

AIM: Ventriculoatrial (VA) shunting is a well-described cerebrospinal fluid diversion method for the treatment of hydrocephalus. However, it may be very challenging in infants and little children because of atrial catheter placement difficulties. This study aimed to create an algorithm to solve problems faced during open surgical procedures based on the present authors' experience. MATERIAL AND METHODS: We conducted a retrospective analysis on 18 infants and children who underwent VA shunt insertion at the Department of Neurosurgery, Ondokuz Mayis University School of Medicine Hospital between 2005 and 2012. Complications, clinical outcomes, revisions, and solutions for overcoming distal catheter placement difficulties were evaluated. RESULTS: Twenty-six VA shunt operations were performed in 18 patients. Six patients required eight VA shunt revisions. VA shunting was primarily performed from the internal jugular, facial, cephalic, and subclavian veins to the right atrium. In revision procedures, the internal jugular, cephalic, and subclavian veins were used. CONCLUSION: VA shunting in infants and little children requires careful surgical techniques. Neurosurgeons should necessarily have an appropriate strategy for VA shunting considering the complications and revisions. Our results suggest open surgical solutions to overcome distal catheter placement difficulties in this age group.

Searching Evidences of Stroke in Animal Models: A Review of Discrepancies A Review of Discrepancies.

So far, animal models have helped us better understand the pathophysiology of the ischemic brain damage but they could not contribute so much to clinical practice. The discrepancies in results regarding neuroprotective agents in animal experiments compared to clinical trials have not been solved. Various animal models of ischemic stroke have proven efficacy of many neuroprotective agents without any considerable result in phase III clinical trials. As is well known, stroke-related focal cerebral ischemia or cardiac arrest related global cerebral ischemia are major causes of disability and death among human subjects. Animal models are essential to evaluate the therapeutic approaches for humans. In this review, we will try to answer two important questions: 1) Which factors endanger the reliability of experimental studies of stroke on animal models? 2) How can we design our experiments to reflect the neurorestoration and/or neuroprotection mechanisms following ischemic injury, when it comes to human disease?

CSF hydrothorax: neither migration of peritoneal catheter into the chest nor ascites. Case report and review of the literature.

INTRODUCTION: Complications of ventriculoperitoneal (V/P) shunt surgery are generally due to infection, or mechanical or dynamic dysfunction. Thoracic complications like cerebrospinal fluid (CSF) hydrothorax are rarely seen. PATIENT AND METHODS: We present a CSF hydrothorax patient as a rare complication of V/P shunt surgery and review of the literature. The patient was a 7-month-old girl who had V/P shunt surgery for hydrocephalus. Six months after surgery, she was admitted to hospital with the complaint of cough. As the chest X-ray revealed hydrothorax, a chest tube was inserted. Although her shunt tip was in the abdominal cavity in shuntograms, positive beta-2 transferrin in liquid sample and Tc 99m cisternography proved that it was CSF. After we replaced her V/P shunt with a ventriculoatrial shunt, the liquid coming from the chest tube progressively diminished and disappeared, and her chest tube was removed. RESULTS: There are 36 CSF hydrothorax cases, including the present case, in the literature. There is peritoneal catheter migration into the chest in 22 of them (61.1 %). Half of the remaining 14 cases (38.9 %) without catheter migration have also CSF ascites. But, in the other half (seven cases), there is neither catheter migration nor CSF ascites as in the present case. CONCLUSION: CSF hydrothorax following V/P shunt surgery is a very rare complication that may cause serious respiratory distress. It is important to keep in mind that peritoneal catheter migration into the chest may or may not occur. Even ascites may not accompany CSF hydrothorax in a patient without peritoneal catheter migration.

The paramedian supracerebellar-transtentorial approach to the entire length of the mediobasal temporal region: an anatomical and clinical study. Laboratory investigation.

OBJECT: The exploration of lesions in the mediobasal temporal region (MTR) has challenged generations of neurosurgeons to achieve an appropriate approach. To address this challenge, the extensive use of the paramedian supracerebellar-transtentorial (PST) approach to expose the entire length of the MTR, as well as the fusiform gyrus, was investigated. METHODS: The authors studied the microsurgical aspects of the PST approach in 20 cadaver brains and 5 cadaver heads under the operating microscope. They evaluated the features, advantages, difficulties, and limitations of the PST approach and refined the surgical technique. They then used the PST approach in 15 patients with large intrinsic MTR tumors (6 patients), tumor in the posterior fusiform gyrus with mediobasal temporal epilepsy (MTE) (1 patient), cavernous malformations in the posterior MTR including the fusiform gyrus (2 patients), or intractable MTE with hippocampal sclerosis (6 patients) from December 2007 to May 2010. Patients ranged in age from 11 to 63 years (mean 35.2 years), and in 9 patients (60%) the lesion was located on the left side. RESULTS: In all patients with neuroepithelial tumors or cavernous malformations, the lesions were completely and safely resected. In all patients with intractable MTE with hippocampal sclerosis, the anterior two-thirds of the parahippocampal gyrus and hippocampus, as well as the amygdala, were removed selectively through the PST approach. There was no surgical morbidity or mortality in this series. Three patients (20%) with high-grade neuroepithelial tumors underwent postoperative radiotherapy and chemotherapy but needed a second surgery for recurrence during the follow-up period. In all patients with MTE, antiepileptic medication could be decreased to a single drug at lower doses, and no seizure activity has occurred until this point. CONCLUSIONS: The PST approach provides the surgeon precise anatomical orientation when exposing the entire length of the MTR, as well as the fusiform gyrus, for removing any lesion. This is a novel technique especially for removing tumors involving the entire MTR in a single session without damaging neighboring neural or vascular structures. This approach can also be a viable alternative for selective removal of the parahippocampal gyrus, hippocampus, and amygdala in patients with MTE due to hippocampal sclerosis.

Bilateral origin of superior cerebellar arteries from the posterior cerebral arteries, and clues to its embryologic basis.

The superior cerebellar artery is the most consistent branch of the basilar artery and arises near the bifurcation of the basilar artery. A bilateral origin of the superior cerebellar arteries from the posterior cerebral arteries has been rarely reported in the literature. Reporting variations in brain vessels is important for neurosurgeons to safely and confidently treat pathologies in this region. We report on a specimen with a bilateral origin to the superior cerebellar artery from the posterior cerebral artery and discuss the embryogenesis of this rare variation.

Hyperdopaminergic status in experimental Huntington disease.

Huntington disease has been linked to increased dopaminergic neurotransmission in the striatum, and clinical studies have demonstrated that the associated chorea can be treated with dopamine antagonist or dopamine-depleting drugs. The origin of this hyperdopaminergic status is unknown. Because substantia nigra pars compacta and the ventral tegmental area are the main sources of striatal dopamine input, we hypothesized that changes in these regions relate to striatal dopaminergic alterations. Here, in a recently generated transgenic rat Huntington disease model that shows progressive striatal neurodegeneration and chorea, we found evidence of increased dopamine levels in the striatum. We also demonstrate more dopaminergic cells in the substantia nigra pars compacta and ventral tegmental area in these rats. These results suggest that increased striatal dopamine comes from these 2 main nuclei, and that it is not necessarily related to shrinkage of the striatum. The findings implicate increased dopamine input from these nuclei in the pathogenesis of chorea in Huntington disease.

Localization of pterion in neonatal cadavers: a morphometric study.

PURPOSE: Pterion is defined as a junction of temporal, frontal, parietal, and sphenoid bones. In newborns, pterion may be defined as a region that shows variability in the exact location because of the lack of complete bony structure. The aim of this study is to define the topographic anatomy of this important surgical point, pterion, and the variability of its localization on craniums of newborn cadavers. METHODS: Our study was performed using 35 term neonatal cadaver specimens. We measured the distances between the pterion and other critical points and used a scale diagram for the definition of pterional area. RESULTS: Our scale diagram showed that pterion is mostly localized in regions c, d, e, and f on the length and regions 2, 3, 4, and 5 on the width. Localization was not observed in regions a, b, g, and h, and in areas of squares 1 and 6. The most observed localization of pterion was the e4 (24.28%) area. CONCLUSION: This study provides a detailed knowledge on localization of this important point, pterion, which will be useful for the clinicians at operation planning and treatment stages, serving for the success in surgery in the presence of this variable topographic cranial anatomy.

The perforating branches of the P1 segment of the posterior cerebral artery.

The perforating branches of the P1 segment of the posterior cerebral artery are vulnerable to injury. Because of their close proximity to the basilar artery, the vulnerability occurs especially during surgical interventions for vascular pathologies such as basilar apex aneurysms. Therefore, extensive knowledge of the microsurgical anatomy of this area is mandatory to prevent poor post-operative outcomes. We microscopically examined 28 P1 segments obtained from 14 adult fresh cadaver brains (6 silicone injected, 8 freshly examined). The P1 segments ranged between 2.8mm and 12.2mm (mean 6.8mm) in length with a mean outer diameter of 1.85 mm (range 0.8-4.5mm). All 94 thalamoperforating branches identified in 27 P1 segments (mean 3.35 branches per segment) arose from the postero-superior aspect of P1 and were the most proximally originating branch in nearly all specimens (96.4%). In addition in 28 P1s, 12 short circumflex arteries (42.8%; mean 0.42 branches per segment), 16 long circumflex arteries (57.1%; mean 0.57 branches per segment) and 10 medial posterior choroidal arteries (35.7%; mean 0.35 branches per segment) were identified and all originated from the posterior or postero-inferior surface of the P1 segment. When the P1 segment had more than one type of branch, it was the short circumflex arteries that were always more proximal in origin than the others. The medial posterior choroidal arteries were always more distal in origin. All three branches were not observed together in any of the P1 segments. The findings in this, and future, anatomical studies may help to reduce the post-surgical morbidity and mortality rates after surgery for posterior circulation aneurysms.

A training model head of plaster of Paris for stereotactic localization.

BACKGROUND: A head model for experiencing stereotactic localization will supply familiarity with stereotactic instruments and self confidence for attempters of stereotaxy before real experience. METHOD: Plaster of Paris was molded as a model head in a plastic ball. Then, it was partly chipped at its superior half, and metal pieces were inserted into those chipped surfaces. Later, the stereotactic frame was applied, and axial computed tomographic scanning was obtained. The metal pieces seen on scans were selected as targets, and their coordinates were calculated using the software of the stereotactic equipment. Lastly, the stereotactic needle was introduced with these coordinates for investigation of targeting. RESULTS: The model of plaster of Paris head was very suitable for rigid frame fixation. The metal pieces in the model head were clearly observed on computed tomographic scans. The stereotactic biopsy needle introduced with the perviously calculated coordinates was always successful in true targeting. CONCLUSION: This easily performed model head supplied us with familiarity with our stereotactic apparatus and convinced us for further attempts. This kind of model and more complicated ones may help for stereotaxy training in neurosurgery.

Sponge pieces as retractors in neurosurgical interventions.

BACKGROUND: Different retractors including high-technology products were proposed for neurosurgical interventions. The sponge, having characteristics of deformability and resistance to compression, might be an alternative retractor for the neurosurgical era. METHODS: Sponge obtainable from the ordinary market was broken into pieces and sterilized by ethylene oxide. During intervention, the appropriate sponge pieces were applied inside the dissected sulci for the purpose of retraction. RESULTS: The sponge pieces were easily applied and supplied optimal retraction during operations. Proximal application to the dissected sylvian fissure enabled the exposure of the inner distal part including the insular surface, whereas application between the frontobasal surface and the orbital roof provided satisfactory exposure of the suprachiasmatic area. The retraction capacity of the sponge was less than that of self-retaining Leyla retractors, but the postoperative appearance of cortical surfaces was fine without any bruising or hyperemia. CONCLUSION: The sponge material, with its inner mechanical characteristics and ease of application like cotton pads, seems to be an alternative retractor in neurosurgical interventions, and these characteristic may inspire development of new high-technology retractors.

Circumferential stabilization with ghost screwing after posterior resection of spinal metastases via transpedicular route.

Various surgical methods have been described for treating spinal metastases, namely, en bloc spondylectomy, minimally invasive techniques, and anterior and posterior approaches. The main goals in surgical intervention for these lesions are tumor removal and establishment of strong, durable stabilization. The least invasive method is always preferred. Posterior transpedicular spondylectomy meets all these needs, as this method achieves tumor excision and stabilization of the anterior and posterior spine through one posterior incision and in the same surgical session. The surgeon circumferentially excises a spinal metastasis and then achieves circumferential stabilization in the same session. Numerous circumferential stabilization methods have been used to date, including placement of free bone grafts or cages or acrylic grafts, or insertion of an acrylic graft supported by a Steinmann pin anteriorly and by posterior transpedicular fixators or a Luque rectangle posteriorly. This article describes seven cases of spinal metastasis in which an alternative circumferential stabilization technique known as "ghost screwing" was performed. The first step in this method is circumferential decompression, achieved with laminectomy followed by eggshell corpectomy via the transpedicular route. Then a short segmental transpedicular stabilization system is fixed to the vertebrae cranial and caudal to the laminectomy/corpectomy defect. Prior to fixing the rods in place, an additional screw is mounted on each rod such that the screw shaft protrudes into the defect space. Once the rods are fixed and the two extra screws are optimally positioned, acrylic bone cement is introduced into the defect site, encasing the ghost screws and forming an anterior graft upon hardening. The outcomes in our cases were excellent. All seven patients had uneventful postoperative periods and all experienced pain relief and were able to mobilize early. Direct connection of the anterior acrylic graft to the posterior fixation system via ghost screws makes this system strong and durable, and prevents subsidence or horizontal displacement of the graft. Such complications can be serious issues with other circumferential systems that use independent anterior and posterior fixators.

A quick-solidifying, coloured silicone mixture for injecting into brains for autopsy: technical report.

The injection of cadaver brains is invaluable for anatomic study, but cadavers that have been properly handled are not easy to obtain. A large number of cadavers pass through forensic departments around the world, and these cadavers could provide hundreds of research specimens, though they remain in the forensic unit for only a short time. The injection of a silicone mixture that quickly solidifies during autopsy would provide greater numbers of fresh specimens for study. The authors describe a technique for injecting a self-curing silicone mixture that can be used on autopsy specimens in a forensic unit. This technique does not interfere with routine autopsy findings. We describe the preparation of the mixture and autopsy specimens, the injection process, and the method for removing injected brains from cadavers. The solidifying process took a 1-h duration in this injection method and was in accord with autopsy procedure. The arterial bed was satisfactorily filled, and even small perforating branches and pial anastomoses were well demonstrated. Injecting autopsy specimens with the quick-solidifying silicone mixture allows anatomical studies of specimens even from cadavers admitted to forensic departments for only a short time. This method can provide neurosurgery laboratories with sufficient numbers of specimens appropriate for various studies.

[Surgical treatment of essential hypertension resistant to medical treatment: Report of two cases]. / Medikal tedaviye dirençli esansiyel hipertansiyonda cerrahi tedavi: iki vakanin sunumu.

OBJECTIVE: To demonstrate that microvascular decompression of the left medulla oblongata is a safe and effective treatment modality in the treatment of "essential" hypertension. METHODS: Two patients with medically refractory hypertension underwent microvascular decompression of the left rostral ventrolateral medulla oblongata. Causes such as renal diseases, carcinoid syndrome, pheochromocytoma were ruled out before surgery. Indications for surgery included mainly systolic blood pressures greater than 180 mm Hg or uncontrolled blood pressures under three or more medications. RESULTS: Both patients experienced more than 20 mm Hg reduction in systolic blood pressure although the number of medications was decreased after surgery. CONCLUSION: Microvascular decompression of the left rostral ventrolateral medulla oblongata may be an effective modality in the treatment of "essential" hypertension.