Cihan Isler

Surgical treatment of trigonocephaly: technique and long-term results in 48 cases.

OBJECT The authors present their experience in the surgical treatment of metopic synostosis by orbital bandeau remodeling and frontal bone rotation. The pitfalls and advantages of the surgical technique are discussed, along with the long-term clinical results in 48 consecutive cases. METHODS Forty-eight consecutive patients in whom trigonocephaly was diagnosed between 1990 and 2009 were treated with frontal bone rotation and frontoorbital bandeau remodeling. Of these patients, 38 (79%) were boys and 10 (21%) were girls. The age at the time of surgical treatment ranged between 4 and 42 months (mean ± SD 11.4 ± 8.7 months). The average follow-up period was 5.5 ± 4.2 years (range 5 months-19 years). The preoperative and latest postoperative photographs of the patients were evaluated for the following features: 1) shape of the forehead; 2) hypotelorism; and 3) temporal depression. Scores of 0, 1, or 2 were assigned for each item: 0 was normal, 1 meant moderate deformity, and 2 denoted severe deformity. RESULTS In the early postoperative period, no complications were documented. The average hospitalization period was 4 days. Follow-up radiographs or 3D CT scans were obtained at regular intervals. The mean preoperative scores for the evaluated items were 1.38 ± 0.49 for the shape of the forehead, 1.33 ± 0.48 for hypotelorism, and 1.7 ± 0.46 for the temporal depression. The mean postoperative scores were 0.06 ± 0.24 for the shape of the forehead, 0.21 ± 0.4 for hypotelorism, and 0.67 ± 0.48 for the temporal depression. Overall, the total preoperative score dropped from 4.4 to 0.93 postoperatively (p < 0.05). All the patients were contented with the cosmetic results. CONCLUSIONS Early detection and treatment of metopic suture synostosis has a significant, favorable influence on the outcomes. Good understanding of the structural abnormality and the pathophysiological mechanisms of the possible complications is very important for performing proper surgical reconstruction.

The expression of astroglial glutamate transporters in patients with focal cortical dysplasia: an immunohistochemical study

PurposeAn abnormal increase in the extracellular glutamate is thought to play a crucial role in the initiation, spread, and maintenance of seizure activity.In normal conditions, the majority of this excess glutamate is cleared via glial glutamate transporters (EAAT-1 and EAAT-2). We aimed to examine the immunohistochemical expression of these transporters in the dysplastic tissues of patients with focal cortical dysplasia (FCD).MethodsThe parafin-embedded dysplastic tissues of 33 patients who were operated on due to medically intractable epilepsy and histopathologically diagnosed with FCD between 2001 and 2006 were stained immunohistochemically with appropriate antibodies, and the distribution and intensity of immunoreactivity (IR) of EAAT-1 and EAAT-2 were examined.The findings were compared with the histologically normal tissues of five patients who underwent temporal lobectomy for epilepsy surgery and 10 fresh postmortem cases.ResultsIn the majority of the patients, the EAAT-1 and EAAT-2 IR were decreased, their astrocytic expression were lower, and the pattern of distribution were more diffused when compared to the control groups.Analyzing these findings according to the types of FCD revealed that as the severity of the dysplasia increased, the IR and astrocytic expression of both transporters are decreased and their distribution tend to be more “diffused.”ConclusionThe results of this study suggest a relationship between the decreased glutamate transporter expressions in dysplastic tissues which,in turn, may cause increased extracellular concentrations of glutamate and FCD pathophysiology.Further studies with larger patient populations,investigating the expression of glutamate transporters at mRNA and protein levels, are required to clarify their roles in the pathophysiology of FCD.

Neuronal nitric oxide synthase expression in glial tumors: correlation with malignancy and tumor proliferation

Abstract Introduction: Increased vascular permeability, vasodilatation, neovascularization and free radical injury in malignant tumors and adjacent normal tissues are believed to be mediated by nitric oxide (NO). High levels of neuronal nitric oxide synthase (nNOS) have been demonstrated in cultured and intracerebral cells. Our aim was to investigate nNOS expression in human glial tumors and to assess its correlation with the histologic grade and proliferative potential. Methods: Tissue specimens were obtained from 29 patients with supratentorial astrocytomas [15 glioblastoma multiforme (GBM), six anaplastic astrocytomas (AA) and eight low grade astrocytomas (LGA)] diagnosed and classified according to the current WHO classification of nervous system tumors. Immunohistochemical staining was performed in paraffin embedded specimens with polyclonal anti-nNOS antibody, and the levels of nNOS expression was evaluated as slight, moderate or dense on the basis of intensity and the extent of distribution of nNOS immunoreactivity. Proliferative potential was evaluated with immunostaining for Ki-67. Results: There was a significant positive correlation between the histologic grade and nNOS expression in terms of intensity and the extent of distribution of nNOS immunoreactivity (p<0.05). Greater values of Ki-67 indices were demonstrated in tumors with higher nNOS expression, indicating a positive correlation between proliferative potentials and expression of nNOS immunoreactivity. Conclusion: Our study suggests that nNOS expression is increased in glial tumors, which was significantly correlated with histologic grade and proliferative potential. NO overproduction due to overexpression of nNOS activity, seems to have significant correlation with malignancy in glial tumors, and may provide another target for anti-proliferative therapy in the future.

Epilepsy-related brain tumors

Seizures are among the most common presentations of brain tumors. Several tumor types can cause seizures in varying rates; neuroglial tumors and the gliomas are the most common ones. Brain tumors are the second most common cause of focal intractable epilepsy in epilepsy surgery series, with the highest frequency being dysembryoplastic neuroepithelial tumors and gangliogliomas. Seizure management is an important part of the treatment of patients with brain tumors. This review discusses clinical features and management of seizures in patients with brain tumors, including, neuroglial tumors, gliomas, meningioma and metastases; with the help of recent literature data. Tumor-related seizures are focal seizures with or without secondary generalization. Seizures may occur either as initial symptom or during the course of the disease. Brain tumors related epilepsy tends to be resistant to antiepileptic drugs and treatment of tumor is main step also for the seizure treatment. Early surgery and extent of the tumor removal are important factors for achieving seizure freedom particularly in neuroglial tumors and low grade gliomas. During selection of the appropriate antiepileptic drug, the general approach to partial epilepsies can be followed. There are several factors influencing epileptogenesis in brain tumor-related epilepsy which also explains clinical heterogeneity of epilepsy among tumor types. Identification of molecular markers may guide future therapeutic approaches and further studies are needed to prove antitumor effects of different antiepileptic drugs.

An experimental model of traumatic nasoethmoidal cerebrospinal fluid fistula.

Cerebrospinal fluid fistula secondary to head trauma is a potentially dangerous problem and precise localization and radical treatment is mandatory. The diagnostic technique is either computed tomography cisternography or MR cisternography. For evaluating the safety of diagnostic modalities and efficacy of treatment especially in terms of surgery, animal studies demonstrating traumatic cerebrospinal fistula model are indispensable not only for neurosurgeons but also for neuroradiologists. The authors in this paper describe a traumatic cerebrospinal fistula in an animal model using rabbits. The cerebrospinal fluid leakage was demonstrated successfully in all eight rabbits and was verified by computed tomography cisternography. The results led us to conclude that rabbit model of traumatic cerebrospinal fluid fistula is safe and has low mortality and morbidity rates. Further studies including larger number of animals should be considered in order to verify safety more accurately.

Microsurgical anatomy of the cisternal anterior choroidal artery with special emphasis on the preoptic and postoptic subdivisions

OBJECT The object of this study was to delineate the microsurgical anatomy of the cisternal segment of the anterior choroidal artery (AChA). The authors also propose a new classification of this segment on the basis of its complicated course within the carotid and crural cisterns in relation to important neurovascular structures, and the site of origin, course, and areas of supply of perforating arteries. METHODS Thirty cadaveric cerebral hemispheres injected with colored latex were dissected under surgical magnification to view the cisternal segment of the AChA and its perforators. Fiber dissections using the Klingler technique were performed in two additional latex injected hemispheres to follow the penetration points, courses, and terminal areas of supply of perforating branches that arise from the cisternal segment of the AChA. RESULTS The cisternal segment of the AChA was divided into pre- and postoptic parts that meet at the arterys genu, the most medial extension point of the cisternal segment where the artery makes an abrupt turn after passing under the optic tract. The preoptic part of the AChA extended from its origin at the inferomedial side of the internal carotid artery to the arterys genu, which is commonly located just inferomedial to the initial part of the optic tract. The postoptic part coursed within the crural cistern and extended from the genu to the inferior choroidal point. The genu of the AChA was 8 mm medial to the arterys origin and was located medial to the optic tract in 13% of the hemispheres. The postoptic part was longer than the preoptic part in all hemispheres and had more perforating arteries supplying critical deep structures (preoptic 3.4 per hemisphere vs postoptic 4.6 per hemisphere), and these results were statistically significant (p = 0.01). At the preoptic part, perforating arteries arose from the superolateral portion of the artery and coursed laterally; at the postoptic part, perforators arose from the inferomedial portion of the artery and coursed medially. Perforating arteries from both segments passed most commonly to the optic tract, followed by the anterior segment and apex of uncus in the preoptic part and the cerebral peduncle in the postoptic part. CONCLUSIONS Both parts of the cisternal segment of the AChA come into surgical view during surgeries for different pathologies in and around the perimesencephalic cisterns. However, attending to the arterys genu and defining pre- and postoptic parts during surgery may help the surgeon locate the origin and eventual course of these perforators, and even estimate the terminal areas of supply of most of the perforating arteries. The proposed classification system can prove helpful in planning any operative procedure along the crural cistern and may reduce the probability of inadvertent injury to perforating branches of the cisternal segment.

Low-profile 1-piece bifrontal craniotomy for anterior skull base approach and reconstruction

Objective: The anterior skull base is a location of many pathologic lesions. These pathologic lesions are treated by bifrontal craniotomy and anterior skull base approach, either primarily or combined with facial osteotomies. To obtain wide exposure, low-profile craniotomies are preferred. In this article, we attempt to describe our own technique of frontal craniotomy for anterior skull base approach. In this technique, the frontal bone, frontal sinus, and the superior supraorbital bar are elevated in en bloc fashion. Methods: Bicoronal skin incision is followed by dissection and retraction of the skin flap in the epigaleal plan. The pericranial galeal flap is dissected separately in subperiosteal fashion until the superior orbital rim. After dissection and retraction of the tip of the temporal muscles, bilateral pterional key burr holes and 1 or 2 parasagittal burr holes are opened. The sagittal burr hole(s) is placed in the point where the upper horizontal surface of the frontal bone slopes vertically downward the forehead. With the craniotome rotating tip (Midas F2/8TA23, Medtronic Inc, Ft Worth, TX), bone cut is made between the pterional key burr holes, passing through the superior orbital bar and the anterior wall of the frontal sinus. To minimize the brain retraction, the operating microscope is placed beside the head, and exposure from the lateral view angle is obtained. Reconstruction of the defect is performed by using pericranial galeal flap and/or Cortoss (Orthovita, Malvern, PA). Results: With this approach, wide exposure of the anterior skull base pathologic lesions was achieved with minimal brain retraction. In the postoperative period, patients tolerated this approach well with favorable functional and cosmetic outcomes. No infections or adverse effects related to this technique or Cortoss were observed. Conclusions: Anterior skull base pathologic lesions can be widely exposed by low-profile bicoronal craniotomy and anterior skull base approach with minimal brain retraction. This wide exposure allows us to gain more control of the pathologic lesion with better resection and reconstruction, reflected on the prognosis of the patients.

Compatibility of MRI and FDG-PET findings with histopathological results in patients with focal cortical dysplasia

PURPOSE The present study aimed to determine if the specific characteristics of fluorodeoxyglucose-positron emission tomography (FDG-PET) analyses of the FCD subgroups were compatible with the magnetic resonance imaging (MRI) and clinical findings of the patients in these subgroups. METHODS This study included 71 patients who had a presurgical evaluation workup performed due to drug-resistant seizures, who underwent epilepsy surgery, and who were histopathologically diagnosed with FCD. Relationships involving MRI and FDG-PET findings and clinical data from pathological subgroups and patients were assessed. RESULTS According to the International League Against Epilepsy (ILAE) classifications of FCD, 28 of the patients were type I and 43 were type II. FCD was visible on the MRI scans of 53 patients, and a majority of this group was classified as type II FCD (n=34). Of these 53 patients, FCD was located in the temporal area of 21 patients, the extratemporal area of 29 patients. Of the patients who exhibited FDG-PET hypometabolism (PET-positive), 23 were classified as temporal, 17 as frontal, 11 showed involvement of the posterior cortex. The age of seizure onset was younger in PET-positive patients (p=0.032), and histopathological analyses revealed that 23 patients had type I FCD and 30 patients had type II FCD. CONCLUSION PET scans reveal a lesion by showing hypometabolism in patients who have refractory epilepsy and an early age of onset with FCD. The lesions of MRI-negative/PET-positive FCD patients tend to be localized in the temporal lobe and that FCD may be localized in the frontal lobe of MRI-negative/PET-negative patients. However, the histopathological examinations of MRI-positive/PET-positive, MRI-negative/PET-positive, and MRI-negative/PET-negative patients did not exhibit a particular histopathological subtype.

Is Chronic Curcumin Supplementation Neuroprotective Against Ischemia For Antioxidant Activity, Neurologic Deficit Score, Or Neuronal Apoptosis In An Experimental Stroke Model?

AIM To investigate the neuroprotective effect of chronic curcumin supplementation on the rat forebrain prior to ischemia and reperfusion. MATERIAL AND METHODS Forebrain ischemia was induced by bilateral common carotid artery occlusion for 1/2 hour, followed by reperfusion for 72 hours. Older rats were divided into five groups: Group I received 300 mg/kg oral curcumin for 21 days before ischemia and 300 mg/kg intraperitoneal curcumin after ischemia; Group II received 300 mg/kg intraperitoneal curcumin after ischemia; Group III received 300 mg/kg oral curcumin for 21 days before ischemia; Group IV had only ischemia; Group V was the sham-operated group. The forebrain was rapidly dissected for biochemical parameter assessment and histopathological examination. RESULTS In forebrain tissue, enzyme activities of superoxide dismutase, glutathione peroxidase, and catalase were significantly higher in Group I than Groups II or III (p < 0.05) while xanthine dehydrogenase and malondialdehyde enzyme activities and concentrations of interleukin-6 and TNF-alpha were significantly lower in Group I when compared to Groups II and III (p < 0.05). A significant reduction in neurological score was observed after 24 and 72 hours in the curcumin-treated groups compared with the ischemic group. We also found a marked reduction in apoptotic index after 72 hours in the groups receiving curcumin. Significantly more TUNEL-positive cells were observed in the ischemic group compared to those treated with curcumin. CONCLUSION We demonstrated the neuroprotective effect of chronic curcumin supplement on biochemical parameters, neurological scores and apoptosis following ischemia and reperfusion injury in rats.

Endoscopic endonasal cerebrospinal fluid leak repair on the ventral midline skull base: a single neurosurgical center experience

AIM To present the results of endoscopic endonasal repair of ventral midline skull base cerebrospinal fluid (CSF) leak (VMSBL) at our institution and to discuss the technique and results from a neurosurgical perspective. MATERIAL AND METHODS A retrospective analysis of all VMSBL cases that underwent endoscopic endonasal skull base approach (EESBA) for CSF leak repair at a single tertiary neurosurgical center was performed. Twenty six patients with an average age of 44.4 (range: 17-63) years were included in the study. RESULTS The etiology of VMSBL was spontaneous in 16 patients, traumatic in 7, and iatrogenic in 3. The leakage site was the cribriform plate in 13 patients, ethmoidal cells in 7, and sphenoid sinus in 3. There were multiple leaks in 3 patients. This approach for VMSBL repair was performed 28 times on 26 patients. The success rate was 88.5% (23/26 patients) after primary endoscopic repair and 96% after the second attempt. The location of the leakage site relative to the upper attachment of the middle turbinate played a crucial role in the anteriorly located VMSBL, which made an impact on the surgical repair plan. All the 16 cases with accompanying meningoencephaloceles were treated successfully by EESBA. Use of vascularized pedicled flaps to support the repair site resulted in 100% success after primary repair. CONCLUSION EESBA is safe and highly effective and can be a first-line surgical treatment option for VMSBL. In addition, it enables adequate reconstruction of ventral midline skull base meningoencephaloceles regardless of size and location.