Endoscopic Third Ventriculostomy: A Single-Center Experience in Greece.

Endoscopic third ventriculostomy is an important tool in the treatment of various forms of adult hydrocephalus, and its use is evolving over the past years, proving in many cases more effective than the more traditional ventriculoperitoneal shunts. We present the experience from our department while comparing the results and complications with the international literature.

Current concepts on the mechanisms of dystonia and the beneficial effects of deep brain stimulation.

The application of lesioning procedures in the basal ganglia and, more recently, of deep brain stimulation (DBS) has revolutionalized dystonia treatment. However, our understanding of the mechanism of action of DBS is only minimal. This is largely due to a rudimentary understanding of dystonia pathophysiology itself, which in turn reflects an insufficient understanding of the functional significance of the cortico-striato-pallido-thalamocortical loops. The initial dystonia pathophysiology concept was one of changes in oscillation rate. Soon, it was realized that not only rate but also the pattern of basal ganglia activity is crucial in the etiology of the disease. The observations of altered somatosensory responsiveness and cortical neuroplasticity, along with the vast array of clinical phenotypes, imply the need for a wholistic neuronal pathophysiology model; one in which an underlying defect of basal ganglia function results in increased cortical excitability, misprocessing of sensory feedback, aberrant cortical plasticity, and ultimately clinical dystonia. This unified dystonia pathophysiology model, although simplistic, may provide the scaffold on which all incoming research and clinical data becomes united in a meaningful and practical way. In light of this model, the dramatic response of some forms of dystonia to pallidal stimulation, the time latency for the beneficial effect and even the presence of non-responders may be explained. Additionally, it may help in developing a rationale for more efficacious DBS programming, better selection of the timing of surgery, and more successful identification of those candidates that are most likely to respond to DBS.

Recurrence of trigeminal neuralgia due to an acquired arachnoid cyst.

We present the case of a 55-year-old female with pain recurrence after microvascular decompression for trigeminal neuralgia due to development of an arachnoid cyst. Radioimaging studies were inconclusive for vascular compression but showed evidence of fifth nerve distortion. The patient underwent surgical re-exploration, and a cystic lesion of thickened arachnoid containing cerebrospinal fluid was identified and excised. Postoperatively, the patient obtained pain relief. Arachnoid cyst formation may be a possible reason for pain recurrence after microvascular decompression for trigeminal neuralgia, especially when repeat neuroimaging does not show clear evidence of fifth nerve vascular compression. Direct compression from the cyst or arterial pulsation transmission through the cyst to the nerve may be the cause of recurrence.

Brain abscess following intracerebral haemorrhage.

A 79-year old male patient developed a brain abscess as infective transformation of a preceding intracerebral haemorrhage after urinary tract infection. The awareness of brain abscess formation at the site of intracerebral haemorrhage is crucial for early diagnosis and treatment of this rare but potentially fatal complication.

Technical aspects and considerations of deep brain stimulation surgery for movement disorders.

Deep brain stimulation (DBS) represents one of the more recent advancements in Neurosurgery. Even though its most successful applications evolved in movement disorders (MDs), indications now include pain, psychiatric disorders, epilepsy, cluster headaches and Tourette syndrome. As this type of surgery gains popularity and the indications for DBS surgery increase, so it will certainly increase the number of neurosurgeons who will use this neuromodulatory technique. A detailed description of the technical aspects of the DBS procedure, as it is performed in our department, is presented. In our opinion, our method is a good combination of all the well-established necessary techniques in a cost-effective way. This technical article may be helpful to neurosurgeons considering to start performing this type of surgery. It could also prompt others who perform DBS regularly to express their views, and hence, lead to further refinement of this demanding procedure.

Use of a single semilinear incision in Deep Brain Stimulation for movement disorders.

This technical note presents the authors experience in using a single semilinear incision for bilateral implantation of Deep Brain Stimulation electrodes in the treatment of movement disorders, in order to avoid some of the hardware and skin related complications of this procedure. The advantages and disadvantages of this technique are presented and discussed.

Symptomatic syringomyelia secondary to clinically obscure infratentorial tumour.

The formation of a cervical spinal cord syrinx as a result of an infratentorial mass, even though uncommon, has been reported in international literature. In such cases, syringomyelia is usually asymptomatic, while the tumour-related symptoms and signs predominate. We report a patient with a posterior fossa tumour and secondary syringomyelia. In this patient, syringomyelia symptoms and signs were present, and a cervical spine Magnetic Resonance Imaging (MRI) showed a large cervical syrinx. A more careful clinical examination though, revealed a sub-clinical posterior fossa syndrome and brain MRI revealed a large infratentorial meningioma. A posterior fossa craniotomy was performed, followed by complete tumour resection and almost complete remission of the syrinx and its related symptoms. The authors discuss the role of posterior fossa tumour induced tonsillar herniation in the development of secondary syringomyelia, the mechanisms leading to syrinx formation and the conditions that must be fulfilled for that to happen.

Selection of cranial site for shunting debilitated patients.

BACKGROUND/OBJECTIVE: The optimum cranial site for ventricular catheter insertion in CSF shunts is still under debate and there has been no general consensus as far as surgical technicalities are concerned. Furthermore, there have been no reports dealing with appropriate cranial site selection in debilitated patients. The aim of this report is to stress the need to utilize a frontal approach when dealing with patients who are likely to remain bed-bound for long periods and to emphasize the well-known prerequisites such as meticulous surgical technique and peri-operative general and local care. METHOD: A retrospective analysis of all shunt operations and revisions performed in our department during the last 6 years. FINDINGS: This analysis revealed 8 long-term recumbent patients with late valve extrusion (N1 = 5) or primary wound breakdown (N2 = 3), all through the occipital area. Extended periods of bed rest due to neurological disease combined with poor nursing and dietary intake had led to either chronic valve extrusion or wound breakdown. Shunt revision was performed successfully by a frontal approach in 5 whereas 2 tolerated shunt removal and one died of meningitis. CONCLUSION: In debilitated patients or those who are likely to remain bed-bound for long periods, a frontal approach for proximal catheter insertion may help prevent immediate postoperative wound breakdown or late valve extrusion.

Peritumoural haematoma and meningioma: a common tumour with an uncommon presentation.

Spontaneous peritumoural haemorrhage in meningiomas is a rare but serious complication with a grave prognosis. It occurs at the interface between the tumour and the parenchyma, either from the tumour surface or the cortical vessels in association with it. Although several pathophysiologic mechanisms for this complication have been proposed, they all remain speculative. We report a 72-year-old female who presented with sudden onset of headache and a left homonymous hemianopia. Neuroimaging revealed a parasagittal meningioma at the posterior third of the superior sagittal sinus with peritumoural intracerebral haematoma, 1 cm away from the tumour. An uncomplicated gross total excision of the meningioma and aspiration of the haematoma was achieved through a craniotomy. The postoperative course was uneventful with an excellent clinical outcome. Possible mechanisms for this unusual complication are discussed. We emphasise the importance of prompt diagnosis and simultaneous excision of the tumour and aspiration of the haematoma as prerequisites for a favourable outcome.

Infected CNS infusion pumps. Is there a chance for treatment without removal?

BACKGROUND: Intrathecal baclofen administration by means of an implantable pump is nowadays a safe and effective method in the treatment of spasticity. One of the rare but devastating complications of this technique is pump infection, with a variety of Gram (-) and Gram (+) organisms being involved. Treatment of these infections, according to international literature, requires removal of the device and appropriate antibiotic therapy. METHOD: This article reports the authors experience in treating 3 patients with severe, medically intractable spasticity, suffering from infection of the intrathecally-delivering pump. A decision was made not to replace the device, but to treat this complication with pump disinfection and with a new treatment modality that has never been used before, the intra-pocket administration of antibiotics. FINDINGS: In all cases the infection was eradicated and the integrity of the pump maintained. None of the patients required a procedure under general anesthesia. CONCLUSIONS: Removal should no longer be considered the first treatment option in infections of intrathecally delivering pumps, especially those due to non-adherent bacteria, with mild clinical symptomatology. An initial attempt should always be made for conservative treatment. Intra-pocket administration of antibiotics helps in achieving high drugs levels locally, and may prove an important element in our armamentarium against such infections.

Complex neurobehavioural syndrome due to bilateral thalamic glioma.

We present a 65-year-old female with bilateral thalamic astrocytoma. The unusual long survival of this patient allowed the manifestation of a complex neurobehavioural syndrome due to gradual involvement of several thalamic nuclei. An attempt is made to approach the complexity of symptoms according to the anatomical areas, nuclei and thalamic connections infiltrated.

Epidural haematoma after evacuation of contralateral subdural haematoma.

BACKGROUND: Sequentially evolving intracranial bilateral haematomas, where the second haematoma develops after the surgical removal of the first one is rarely reported. AIM: To report a patient who developed an epidural haematoma after evacuation of a contralateral subdural haematoma. METHODS: A 49-year-old male was admitted to our department after head injury. A brain computerized tomography (CT) scan revealed an acute subdural haematoma in the right temporal area which was evacuated. During his stay in the intensive care unit, he was submitted to intracranial pressure monitoring, which soon rose. RESULTS: A new CT scan showed an acute epidural haematoma in the contralateral parietal area that was also evacuated. CONCLUSIONS: While rising intracranial pressure after the evacuation of a traumatic haematoma is usually attributed to brain oedema or recurrent haematoma at the craniotomy site, the development of a contralateral epidural haematoma requiring surgical treatment should not be overlooked.

CT-guided stereotactic biopsies of brain stem lesions: personal experience and literature review.

Appropriate therapy of brain stem lesions should be guided by an accurate diagnosis. Clinical evaluation combined with modern neuroimaging techniques may nowadays approach the diagnosis but not always with accuracy, thus leading to erroneous treatment. We report a series of 11 patients who underwent stereotactic biopsy for brain stem lesions. In 8 patients, the lesion was approached transfrontally. In the remaining 3 patients, the lesion was approached via the suboccipital transcerebellar route. There was no surgical mortality. Precise histological diagnosis was achieved in all patients. Three patients (27.2%) suffered complications attributed to the procedure and were successfully treated conservatively. Histological results were in accordance with preoperative diagnosis in 9 patients (81.8%). Despite the limited number of patients, our data suggest that stereotactic biopsy of brain stem lesions is a safe technique that can obtain adequate tissue for histological diagnosis, thus providing each patient with the best available treatment.

Atypical presentation of an extradural hematoma on the grounds of a temporal arachnoid cyst.

We report a 56-year-old man, with atypical presentation of an extradural hematoma caused by head injury after a fall. The presence of a temporal arachnoid cyst on the grounds of temporal lobe agenesis altered the clinical image of this man, causing only mild symptoms where an otherwise acute neurologic deterioration would be expected in the case of an epidural hematoma of such extent. The hematoma was evacuated through a left pterional craniotomy and a tear in the middle meningeal vein was recognized as the source of bleeding. Postoperative course was uneventful and the patient was discharged within 5 days. An extensive review of literature available to us revealed only 5 other such cases reported that all were younger patients.

Stereotactic biopsy of brain stem lesions.

The successful therapy of space-occupying lesions of the brain stem, depends on precise histological diagnosis. Although the clinical management and contemporary imaging techniques (computerized tomography and magnetic resonance imaging) are now able to reveal and approach the diagnosis in these cases, only the combination of these two with the use of contemporary stereotactic systems, is able to secure the precise histological diagnosis for the patient with a good degree of safety. This study presents the first five patients in Greece with space-occupying lesions of the brain stem, in whom a stereotactic biopsy was carried out. All patients were subjected to CT-guided stereotactic biopsy, via the frontal approach in 4 patients with lesions in the superior pons and the mesencephalon and in one patient via the transcerebellar approach, for a lesion in the lateral surface of the pons. Precise histological diagnosis was possible and on the basis of a reliable choice of histological criteria the appropriate therapeutic approach was chosen, thus avoiding the old "empirical" treatment.

Enhancement of interleukin-4-mediated tumor regression in athymic mice by in situ retroviral gene transfer.

Intratumoral grafting of genetically engineered cells that produce interleukin-4 (IL-4) has been shown to produce tumor regression as well as prolong survival of mice harboring intracerebral gliomas. We sought to determine whether retroviral-mediated gene delivery into tumor cells in situ resulted in enhanced tumor regression by IL-4. Two mouse fibroblast lines were obtained: they both secreted similar levels of IL-4 but one produced a retrovirus vector bearing the IL-4 gene (CRE-MFG-IL-4 cells), whereas the other did not (NIH3T3-IL-4 cells). In mixed transplantation assays in the subcutaneous flanks of athymic mice, CRE-MFG, IL-4 cells were more effective than NIH3T3-IL-4 cells in inhibiting the growth of rat C6 glioma cells (p < 0.005, ANOVA). Subcutaneous tumors injected with fibroblasts that produced a control retrovirus vector without producing IL-4 (CRE-MFG-LacZ cells) did not inhibit subcutaneous tumor growth. An intracranial assay was used to evaluate survival of athymic mice harboring intracranial gliomas. Three days after implanting rat C6 glioma cells into the right frontal lobes of athymic mice, NIH3T3-IL-4 cells (n = 10) or CRE-MFG-IL-4 cells (n = 10) were stereotactically inoculated into the tumor bed. The average survival of mice treated with CRE-MFG-IL-4 cells was 38 days (+/- 2.4, SE), whereas that of mice treated with NIH3T3-IL-4 cells was 31 days (+/- 0.8, SE) (p < 0.005, ANOVA; p < 0.001, log-rank analysis).(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term survival of rats harboring brain neoplasms treated with ganciclovir and a herpes simplex virus vector that retains an intact thymidine kinase gene.

Survival of rats harboring cerebral 9L gliosarcomas can be significantly extended by an intratumoral inoculation with a herpes simplex virus vector, designated as hrR3. This vector, which bears the lacZ reporter gene, is defective in the gene encoding ribonucleotide reductase, allowing for replication in dividing tumor cells but not in postmitotic neural cells. It also possesses an intact viral thymidine kinase (TK) gene, which confers chemosensitivity to ganciclovir. In this study, the ability of ganciclovir to potentiate the antitumor effect of hrR3 was evaluated. In culture, there was a 23% decrease in the growth of 9L cells treated with hrR3 plus ganciclovir compared to hrR3 alone (P < 0.01). The combination of hrR3 plus ganciclovir led to the long-term survival of 48% of rats harboring intracerebral 9L gliosarcomas compared to 20% survival in the hrR3 group (P < 0.05). Ganciclovir treatment had no effect on the growth of tumor cells in vitro or in vivo when a herpes simplex virus vector with a defective TK gene was used. Immunocytochemistry confirmed selective expression of the TK gene in cells within the tumor. These findings indicate that the TK gene can potentiate the antitumor effect of the hrR3 herpes simplex virus vector and provide the basis for placing additional therapeutic genes in the genome of hrR3.