Ramazan Sari

Correlation of pulsatility index with intracranial pressure in traumatic brain injury.

AIM In traumatic brain injury (TBI) patients, it is desired to monitor the intracranial pressure (ICP) to assess the cerebral haemodynamics and guide the therapy. The study was designed to see if the pulsatility index (PI) measured by transcranial Doppler ultrasonography (TCD) predicts information about ICP values. MATERIAL AND METHODS In 52 TBI patients with Glasgow Coma Scale (GCS) score < 9, invasive intracranial monitoring and TCD ultrasonography for PI were performed through five days. ICP, cerebral perfusion pressure (CPP), PI values were recorded and calculated. The correlation and regression analysis between ICP, PI and CPP were investigated in the whole group and in patients with a Glasgow Outcome Score (GOS) of 3-5. RESULTS The decline in ICP and PI values was significant through five days. The correlation between ICP and PI was strongly significant (p < 0.0001) on days 1, 3 and 5. In patients with a GOS of 3-5, correlation of ICP and PI was also observed. The only significant correlation observed between CPP and PI was on day 5. CONCLUSION The strong correlation observed between ICP and PI through the management period of TBI patients can lead us to use TCD ultrasonography-derived PI as a guide if invasive monitoring is not available.

Microsurgical treatment of unruptured intracranial aneurysms

Summary Background. The natural history of unruptured cerebral aneurysms is not clearly defined. Method. Fifteen patients who were diagnosed with unruptured intracranial aneurysms and were surgically treated by clipping at our hospital during the years 2004–2005 were studied retrospectively. Findings. There was no mortality. Early morbidity in this study was 6.6%. One patient developed symptomatic vasospasm after the surgery. Conclusions. In this study, the microsurgical treatment of intracranial unruptured aneurysms was found to be a safe intervention and prevented the possibility of the patients developing subarachnoid haemorrhage, which has high mortality and morbidity.

Microsurgical management of non-neurofibromatosis spinal schwannoma

INTRODUCTION The aim of this study is to assess the clinical properties and surgical results of patients diagnosed with spinal schwannomas without neurofibromatosis (NF) properties. PATIENTS AND METHODS The data obtained from 35 patients who underwent resection of spinal schwannomas were analyzed. All cases with neurofibromas and those with a known diagnosis of NF Type 1 or 2 were excluded. 35 patients underwent surgery for spinal schwannoma at our institution between January 1997 and 2010. The data were gathered retrospectively from medical records and included clinical presentation, tumor location and post-operative complications. All cases were surgically excised, and they were confirmed to be schwannomas by pathologists with histopathological sections in paraffin stained with hematoxylin-eosin. RESULT We treated 35 (20 males and 15 females) patients with spinal schwannomas. The mean age of the patients was 47.2 (between 13 and 76) years. Of the cases, six schwannomas were located in the cervical spine, four in the thoracic spine, two in cervico-thoracic area, 10 in the thoraco-lumbar area and 13 in the lumbar spine. Two patients had malignant schwannomas that were recurrent. Of the 35 cases, the schwannomas were intradural-extramedullary in 30 cases (86%), intradural-intramedullar in 2 cases (6%), and extradural in 3 cases (9%). CONCLUSION Spinal schwannomas may occur at any level of the spinal axis and are most frequently intradural-extramedullary. The most common clinical presentation is pain. Most of the spinal schwannomas in non-NF patients can be resected completely without or with minor post-operative deficits. This knowledge may help us to create a strategy for total resection of a spinal schwannomas.

MGMT gene variants, temozolomide myelotoxicity and glioma risk. A concise literature survey including an illustrative case

Temozolomide may cause thrombocytopenia or neutropenia in 3–4% of glioblastoma patients, respectively. However, pancytopenia is rarely reported. MGMT (O6-methylguanine-DNA-methyltransferase) enzyme repairs temozolomide-induced DNA mutations and associates both with antitumour efficacy and myelosuppression. Many studies on the effects of MGMT gene-methylation on temozolomide’s effects exist, but much fewer publications concerning MGMT variants were documented. A full sequencing of the MGMT gene was performed in a female glioblastoma patient, who developed pancytopenia following temozolomide treatment. Results indicated the presence of all the rs2308321 (I143 V), rs2308327 (K178R) and rs12917 (L84F) MGMT-variants, which were previously associated with temozolomide myelotoxicity. rs12917 (L84F) variant was reported as associating with lesser risk of gallbladder tumours, yet with higher risk of non-Hodgkin lymphomas related with exposure to chlorinated solvents or hair dyes. DNA repair proteins may exert diverging effects on DNA injuries caused by different chemicals and therefore exerting complex effects on myelotoxicity, antitumour activity and carcinogenesis.

Management of failed cranioplasty.

AIM Failed cranioplasty attempts may lead to numerous complications in a broad spectrum including cosmetic problems, infection, neurological deterioration and even death. Selection of the most appropriate surgical technique for second and further surgical attempts for these patients still remains a debate. We aimed to share our experience and technical pitfalls on management of failed cranioplasty, particularly for patients with large cranial defects. MATERIAL AND METHODS A retrospective data analysis of cranioplasty cases in our series was performed including the time period between 2002 and 2012. Patients required recurrent cranioplasty were analyzed in detail. RESULTS Totally, 101 patients underwent cranioplasty for bony defect. Of 101 patients, eleven required a revision surgery due to infection or spontaneous resorption of the bone flap. All patients underwent revision cranioplasty with pre-surgical plaster cast mold technique modified from previous studies and/or tissue expansion technique. Polymethyl-metacrylate (PMMA) was used as substitute for reconstructions. Mean follow-up was 36 months. Two out of eleven cases (18.1%) developed major complications, which led to further revision. At the end, a satisfactory reconstruction was achieved for all patients. CONCLUSION Our modified molded plaster cast technique is a safe and cost-effective approach for the revision of failed cranioplasty. We believe that the tissue expanding techniques have also great contribution to achieve successful results.

Multimodal intraoperative neurophysiologic monitoring in the neurosurgical oncology

AIM Neurosurgical oncology that is performed for lesions located in critical areas like the sensorimotor area has additional risk because it may cause serious neurological deficiencies. Some intraoperative neuromonitoring (IONM) modalities can effectively help the surgeons to maximize resections of this kind of lesions with or without an acceptable neurological deficiency. Our aim was to share our IONM experiences with patients who underwent intracranial lesion surgery in critical areas between September 2013 and January 2015. MATERIAL AND METHODS This retrospective study was performed on 31 patients who underwent brain surgery for the resection of lesions located in eloquent areas. Demographic characteristics, lesion localizations, lesion pathologies, surgery, IONM recordings, and pre- and postoperative neurological examinations were reviewed. RESULTS Five of the 31 patients had lesions in the cerebellopontine angle and 26 patients had lesions close to critical locations. Transcranial motor evoked potentials and somatosensory evoked potentials were performed in 27, electroencephalography in 31, auditory evoked potentials in 8, visual evoked potentials in 2, triggered electromyography in 8, and central sulcus determination and brain mapping in 17 patients. Motor evoked potential changes occurred in 2 patients intraoperatively. One had right hemiparesia lasting 3 days while the other had monoparesia which improved within 2 months. Permanent neurological deficit was not observed. CONCLUSION Intraoperative neuromonitoring helps the surgeons to maximize resection of lesions in or close to eloquent areas of the brain. Using only one modality is not sufficient, whereas a combination of modalities is required to obtain a better outcome.

Immune Pathobiology of Schwannomas: A Concise Review

&NA; Schwannomas are benign tumors treatable with neurosurgery or radiosurgery, yet a small subset may exhibit aggressive growth. Hence illuminating their immune features can help develop better treatments. A tumor‐promoting inflammation exists in schwannomas. Transcription factor NF‐&kgr;B triggers synthesis of inflammatory cytokines and chemokines. NF‐&kgr;B is suppressed by NF2/merlin, yet it is mutated or repressed in schwannomas, and therefore MCP‐1/CCL2, MIP‐1&agr;/CCL3, CXCL16, and CXCR6/Bonzo are likely expressed in these tumors. CD68+ and CD163+ macrophages may infiltrate schwannomas and promote their growth. Anti‐inflammatory salicylates inhibit schwannomas in cell culture and clinically. Schwannomas that cannot be completely removed by neurosurgery or controlled by radiosurgery may be suitable targets of pharmacologic interventions focusing on immune mechanisms.

Multimodal intraoperative neurophysiologic monitoring in the spinal cord surgery.

AIM Intraoperative neurophysiological monitoring (IONM) monitors the functional integrity of critical neural structures by electrophysiological methods during surgery. Multimodality combines different neurophysiological methods to maximize diagnostic efficacy and provide a safety margin to improve the outcomes of spinal surgery. Our aim was to share our intraoperative monitoring experiences with patients who underwent surgery because of spinal cord pathologies between September 2013 and January 2015. MATERIAL AND METHODS We had twenty-six cases. Location of the lesions, surgery, neurological findings, and electrophysiological findings intraoperatively and postoperatively were documented. RESULTS The combination of motor evoked potential (MEP), somatosensorial evoked potential (SSEP), free-run and trigger electromyography (EMG) were performed according to lesion localization. MEPs plus SSEPs were run in 23 patients and MEPs with triggered EMG were performed in 4 patients. In only one patient, optimal recording could not be elicited because of technical problems. MEP and SSEP changes were recorded in 12 and 3 patients respectively. Postoperative neurological deficits were observed in 2 patients. Deficits were transient in one case and permanent in the other. While baseline MEP responses were either absent or low amplitude ( < 50 microvolt) in 7 patients, following resection they were either visible or increased in amplitude. Surgery was ended in one patient with C7-T2 intramedullary tumour after the right distal MEP response disappeared. CONCLUSION Multimodal IONM is an important method to monitor the neural structures under risk in spine surgery and to keep the surgery within safety limits, especially for intramedullary spinal cord lesion surgery.