Mehmet Alptekin

Three-layer reconstruction with fascia lata and vascularized pericranium for anterior skull base defects

SummaryBackground. We report an assessment of the efficiacy of a triple layer graft composed of fascia lata and vascularized pericranium for anterior skull base reconstruction. This technique is based on the concept that vascularized tissue over a free flap may promote vascularization and rapid wound healing. Method. A large fascial graft is prepared from the fascia lata and divided in two pieces and trimmed to a size larger than the bone and dural defect. Vascularized pericranium is harvested after bicoronal incision and elevating the bifrontal scalp flap down to the supraorbital rims. First is dural repair, which is performed with fascia lata placed between the brain and remaining dura. Second, fascia lata is placed over the skull base defect and secured with mini titanium screws over the cranial surface of the orbital ridges. Third, vascularized pericranium is laid between the two layers of fascia lata. Findings. We studied 17 patients of whom 2 had malignancy, 6 had olfactory groove meningioma, 6 had skull base fracture and rhinorrhea, 1 case had orbital meningioma, 1 had invasive pituitary adenoma and 1 had basal encephalocele. The transbasal approach was used as a single procedure in 13 cases. The extended transbasal approach combined with a transfacial approach was used in 3 cases and with a pterional approach in 1 case. In each patient, reconstruction of the cranial base was performed with triple layer graft of fascia lata and vascularized pericranium. The patients were followed-up 2 months to 5 years. None of the patients experienced postoperative cerebrospinal fluid leakage, meningitis, abscess, brain herniation and tension pneumocephalus. Interpretation. Fascia lata with vascularized pericranium is highly reliable, tensile and well suited for reconstruction of the anterior skull base.

Premedication With Dexmedetomidine Alone or Together With 0.5% Lidocaine for IVRA

BACKGROUND This study aimed to compare the effects of low and same dose of dexmedetomidine when added to lidocaine for intravenous regional anesthesia (IVRA) and when administered for premedication before IVRA. MATERIAL AND METHODS In this double blind study, 45 patients with ASA physical status I-II were scheduled to undergo carpal tunnel release as an outpatient procedure and were randomly divided into three groups. IVRA was performed with 40 mL of 0.5% lidocaine in the operating room. A single dose of dexmedetomidine 0.5 μg/kg and placebo (saline) solution in a total volume of 20 mL were administered intravenously to group P (n=15) and group S (n=15), respectively, before IVRA. 0.5 μg/kg of dexmedetomidine was added to lidocaine in group A (n=15) during IVRA. The onset and recovery time of sensory and motor block, intraoperative-postoperative visual analog scale (VAS) and Ramsay sedation scores (RSS), analgesic requirement, hemodynamic variables, and side effects were noted. RESULTS Significantly shortened sensory block onset and recovery time in group P and A, shortened motor block onset time in group P, and decreased intra-postoperative VAS scores and analgesic requirement in groups P and A were found. Intraoperative RSS in group P and postoperative RSS in groups P and A were higher than in group S. Intraoperative and postoperative heart rate and postoperative mean arterial blood pressure (MAP) of group P was significantly lower than groups A and group S, respectively. CONCLUSION Both addition of dexmedetomidine to lidocaine and premedication with dexmedetomidine for IVRA similarly improve quality of anesthesia and perioperative analgesia without important side effects.

Correlation between Rho-kinase pathway gene expressions and development and progression of glioblastoma multiforme.

Glioblastoma multiforme (GBM) is the most common and the most aggressive primary malignant tumor of the brain. Prognostic factors in GBM can be sorted as age, tumor localization, tumor diameter, symptom period and type, the extent of surgery, postoperative tumor volume, and adjuvant radiotherapy and/or chemotherapy status. Besides the interactions between actin microfilaments, microtubules, and intermediate filaments, environmental factors and intracellular signals which regulate them affect the cell invasion. Rho proteins and therefore Rho-kinase activation play important role at these changes. The aim of this study is to evaluate the relationship between the Rho-kinase pathway gene expressions and prognosis in GBM. Ninety-eight patients diagnosed as GBM between 2001 and 2010 were enrolled into the study. RNA was obtained from the paraffinized tumor tissue of the patients with formalin-fixed, paraffin-embedded RNA isolation kit and the mRNA expressions of 26 genes were investigated. There was a statistically significant negative correlation between the ages at the diagnosis and survival. There was a significant relationship between the overexpression of Rho-kinase pathway-related genes LIMK1, CFL1, CFL2, and BCL2 and low expression of MAPK1 gene and the survival of the patients. These results demonstrate for the first time that there is a marked contribution of Rho-kinase pathway-related genes to the progression and survival of the GBM. The expression of these genes may be related to response of multimodal therapy or these parameters could be used to determine possible unresponsive patients before treatment.

Modified IDARAM chemotherapy regimen for primary central nervous system lymphoma: experience of three cases

Abstract The use of radiotherapy (RT) with chemotherapy has improved disease free survival and control in primary central nervous system lymphoma (PCNSL). We have encountered three patients with histologically documented central nervous system lymphoma. In all patients pathological diagnosis was B-cell lymphoma. We modified IDARAM regimen to R-IDARAM to enhance and optimize chemotherapeutic components for the treatment of PCNSL. We made three changes: (i) we added rituximab 375 mg/m2 day 1; (ii) increased dose of MTX from 2 to 3 g/m2; and (iii) administered two additional courses of R-IDARAM after cranial RT. Following complete staging after course 2, radiotherapy was applied at a dosage of 3600–4140 cGy in conventional schedule (180 or 200 cGy per day) to whole brain (with 3600 cGy to eyes in one case because of eye involvement) and then 2 additional courses of R-IDARAM (totally four courses) chemotherapy regimen were applied. Complete remission (CR) was achieved after first two cycles of R-IDARAM in patient 1 and 3 and after four cycles in patient 2. Currently, three patients have been alive for 29, 10, 15 months respectively. Currently there is no standard treatment modality for PCNSL. Increased dosage of MTX, adding rituximab and consolidation of the IDARAM to R-IDARAM regimen may improve disease control and outcome in PCNSL patients.

PRIMARY SPINAL EPIDURAL EXTRAOSSEOUS EWING'S SARCOMA MIMICKING A SPINAL ABSCESS

Ewings sarcoma is one of the most common malignant tumors of the skeletal system in children and young adults. It most frequently stems from the long bones of the extremities. However, though uncommon, extraosseous localization can be seen. Epidural extraosseous presentations are extremely rare. In this case, the authors report on the long-term follow-up of a patient with this well-demonstrated, but uncommon localization, and the initial unique presentation of the patient, which clinically and radiologically mimicked a cervical abscess.

Efficiacy of Methylprednisolone in Acute Experimental Cauda Equina Injury

Summary. In this experimental study the efficiacy of methylprednisolone was investigated by neurophysiological and histopathological evaluation in a rabbit cauda equina model where injury was produced with an aneurysm clip (closed pressure 192 gr). High dose methylprednisolone (kg/30 mg) was administered by intravenous infusion in the 8th, 16th and 24th hours after injury followed by infusion of the same dosage every 6 hours for 24 hours. Nerve conduction velocity was measured before and early after trauma and 3 weeks after injury. Both neurophysiological and histopathological investigations demonstrated the neuroprotective effectiveness of methylprednisolone if it was given in the 8th hour after trauma. Although recovery was observed its efficiacy was less pronounced when it was given in the 16th and 24th hours.

Complications and treatment of chronic otitis media.

ObjectiveThe aim of this study was to investigate the etiologic factors and treatment types for chronic otitis media (COM) complications. MethodsIn this study, the data from 82 patients who had been diagnosed and treated at the Departments of Otolaryngology and Neurosurgery of Gaziantep University between 1999 and 2011 for complications from COM were retrospectively reviewed. The chosen surgical procedure was based on the type of complication and the ear pathology. ResultsThe study included 55 male and 27 female patients. Ten patients (12.2%) had intracranial complications, and 72 patients (87.80%) had extracranial complications. There were 47 patients with cholesteatoma. Radical mastoidectomy was performed on 46 patients, canal-wall-down mastoidectomy was performed on 30 patients, and canal-wall-up mastoidectomy was performed on 6 patients. Five patients underwent neurosurgical operations because of COM complications. ConclusionsAlthough the rate of COM complications has recently declined, it remains important to diagnose COM without delay and to use appropriate treatments for the patients because COM complications are associated with poor outcomes.

Effects of Progesterone on Total Brain Tissue Adenosine Deaminase Activity in Experimental Epilepsy

Single seizure and epilepsy is one of the most commonly encountered neurologic disorders in elderly individuals, arising as a result of complex and often multiple acquired underlying pathologies. Adenosine, acting at A1 receptors, exhibits anticonvulsant effects in experimental epilepsy and inhibits progression to status epilepticus. Adenosine deaminase is the enzyme for the regulation of adenosine levels. Therefore any change in adenosine deaminase levels will reflect to adenosine levels. Adenosine deaminase levels were decreased in the groups that were given progesterone. Progesterone may have an antiseizure effect with the additional finding decreased levels of adenosine deaminase that would have resulted in increased adenosine levels that exerts anticonvulsant effect via GABA-A receptors. Further studies are needed to evaluate the role of progesterone effects on adenosine deaminase levels and its mechanism(s) in the pathogenesis.

Antiepileptogenic Effects of Glutathione Against Increased Brain ADA in PTZ-Induced Epilepsy

Adenosine has been shown to play a significant role as a modulator of neuronal activity in convulsive disorders, acting as an endogenous anticonvulsant agent. Any change in adenosine deaminase (ADA) levels will reflect to adenosine levels. In the present study, we have investigated the effect of glutathione on brain tissue ADA levels due to seizures induced by convulsive and subconvulsive dose of pentylenetetrazol (PTZ) in mice. ADA levels due to seizures induced by convulsive and subconvulsive pentylenetetrazol were measured using the Giusti method. ADA levels were higher in the experimental epilepsy groups than in the control and sham groups. ADA levels significantly decreased in the glutathione groups, which may have antiseizure effects. Decreased levels of ADA would be due to increased adenosine levels, protecting against oxidative stress.

Multicentric Dentigerous Dermoid Cyst with an Unusual Location in the Central Nervous System

Dermoid cysts are benign and congenital ectodermal inclusions. Their occurrence in an intracranial location is quite rare. They constitute 0.1 to 0.7% of all intracranial tumors. Their occurrence in the fourth ventricle and their multicentric feature are extraordinary. A 12-year-old boy was admitted to our clinic with a dermoid cyst with sixth cranial nerve involvement. He had symptoms of increased intracranial pressure. This case is the first dermoid cyst in the literature at this unusual location; a mature tooth structure was found within the cyst, which extended over the cervical subsegments. There was a second dermoid cyst in the thoracic spine (multicentric). Our aim is to present an atypical dermoid cyst along with radiodiagnostic characteristics and macroscopic findings.