Frameless image-guided neuroendoscopy training in real simulators.

BACKGROUND: Over the last decade, neuroendoscopy has re-emerged as an interesting option in the management of intraventricular lesions in both children and adults. Nonetheless, as it has become more difficult to use cadaveric specimens in training, the development of alternative methods was vital. The aim of this study was to analyze the performance of a real simulator, in association with image-guided navigation, as a teaching tool for the training of intraventricular endoscopic procedures. METHODS: 3 real simulators were built using a special type of resin. 1 was designed to represent the abnormally enlarged ventricles, making it possible for a third ventriculostomy to be performed. The remaining 2 were designed to simulate a person's skull and brain bearing intraventricular lesions, which were placed as follows: in the foramen of Monro region, in the frontal and occipital horns of the lateral ventricles and within the third ventricle. In all models, MRI images were obtained for navigation guidance. Within the ventricles, the relevant anatomic structures and the lesions were identified through the endoscope and compared with the position given by the navigation device. The next step consisted of manipulating the lesions, using standard endoscopic techniques. RESULTS: We observed that the models were MRI compatible, easy and safe to handle. They nicely reproduced the intraventricular anatomy and brain consistence, as well as simulated intraventricular lesions. The image-based navigation was efficient in guiding the surgeon through the endoscopic procedure, allowing the selection of the best approach as well as defining the relevant surgical landmarks for each ventricular compartment. Nonetheless, as expected, navigation inaccuracies occurred. After the training sessions the surgeons felt they had gained valued experience by dealing with intraventricular lesions employing endoscopic techniques. CONCLUSION: The use of real simulators in association with image-guided navigation proved to be an effective tool in training for neuroendoscopy.

A model for foramen ovale puncture training: Technical note.

BACKGROUND: Trigeminal neuralgia is a common cause of facial pain, characterized by shock-like pain affecting one or more branches of the trigeminal nerve. When conservative treatment fails and microdecompression is not indicated, percutaneous procedures are helpful. This percutaneous approach is done by a puncture up to the Gasserian ganglion, through the foramen ovale. Although simple and safe, this puncture demands some expertise from neurosurgeons. For that, a partnership between neurosurgeons and bio-engineers has developed a model for foramen ovale puncture, allowing practice for residents and young neurosurgeons. METHOD: A model for foramen ovale puncture has been created by interposition of synthetic materials over a skull, simulating the human face. FINDINGS: This model has shown great similarity with that found in conventional surgeries, even upon repeated testing by experienced functional neurosurgeons and young residents. CONCLUSION: This model for foramen ovale puncture training has demonstrated valuable help for initial practicing of this common neurosurgical procedure, particularly in centers where there are not many cadavers available for training.

[Stereotactic-guided surgery for cavernous angiomas]. / Cirurgia estereotáxica guiada para angiomas cavernosos.

Intracerebral cavernous angiomas may cause hemorrhage, epileptic seizures and neurological deficits. The diagnosis of these lesions became easier with the advent of the magnetic resonance image (MRI). Radical resection is the treatment of choice. Due to frequent subcortical or deep location, image-guided techniques, such as stereotactic-guided surgery, offer many advantages as smaller skin incision and craniotomy, less brain manipulation with consequently lower morbidity. We present a series of nine cavernous angiomas treated by stereotactic-guided radical surgical resection. The diagnosis was done by MRI and confirmed by pathologic studies in all cases. Mean age of patients was 30 years old (range 20-54 years). Postoperative morbidity occurred in two cases: one patient had a convulsion on the third postoperative day and the other presented dysphasia and hemiparesis on the second postoperative day, both with total recovery. Total resection of the lesion was possible in all cases with no neurological deficit.

[Stereotactic implantation of depth electrodes by magnetic resonance image in epilepsy surgery]. / Implantação estereotáxica de eletrodos profundos por ressonância magnética para cirurgia de epilepsia.

We present the case of a 40-year-old woman with refractory epilepsy since aged 18, who was submitted to video-EEG monitoring with intracerebral depth electrodes. The clinical history and examination, magnetic resonance image (MRI), video-EEG and neuropsychological study did not allow the determination of the cerebral onset of epileptic seizures. Depth electrodes inserted by MRI-guided stereotaxis allowed the recording of the epileptic activity and thus showed quite accurately the area of the brain to be surgically resected. She underwent a right anterior temporal lobectomy with amygdalohippocampectomy. The immediate postoperative period was uneventful and she is without epileptic seizures after three months of follow-up. The average pre-operative free-seizure period was two weeks. To our knowledge, this is the first stereotactic surgery for insertion of depth intracerebral electrodes in epilepsy in Brazil.

Talamotomia estereotáxica para hemibalismo / Stereotactic thalamotomy for hemiballismus

O caso de um paciente com hemibalismo direito de origem traumática, refratário ao tratamento medicamentoso e tratado com sucesso por talamotomia estereotáxica é apresentado

Comparison of MRI-guided and ventriculography-based stereotactic surgery for Parkinson's disease.

Stereotactic surgery for Parkinson's disease can be performed using different neuroimaging methods. Ventriculography has been used to locate the coordinates of the structures close to the third ventricle. Although it has several potential disadvantages related to the intraventricular injection of iodine contrast, it is considered a precise method. Computed tomography and magnetic resonance imaging have been used in some centers. In order to compare their efficacy, 50 stereotactic thalamotomies for Parkinson's disease were performed using either ventriculography (VE) (25) or magnetic resonance imaging (MRI) (25). In 14 out of 25 VE procedures, computed tomography (CT-scan) was also used and showed a significant mean difference of coordinate Y and Z. The clinical results employing either VE or MRI were similar, with 80% abolition of tremor in the VE group, and 84% in the MRI group, after a follow up period of at least 3 months. Another 12% of VE and 16% of MRI group showed significant improvement of tremor. Complication rate was 4% in both groups. MRI-guided stereotactic thalamotomy in Parkinson's disease has shown good clinical results, comparable to VE-guided stereotaxis.

Thoracic intraspinal Paracoccidioidomycosis. Case report.

Intramedullary lesions caused by Paracoccidioides brasiliensis have been rarely described. Its diagnosis may be challenging and surgical approach is indicated for diagnostic and therapeutic purposes. We hereby report a case with MRI and surgical findings in a 45 year-old woman with intramedullary paracoccidioidomycosis, and make a review of other cases presented in the literature.

[Stereotactic surgery for intracranial mass lesions: diagnosis and treatment]. / Cirurgia estereotáctica para processos expansivos intracranianos: diagnóstico e tratamento.

The authors present a study about 50 stereotactic procedures for intracranial lesions. In 12 cases stereotaxis was used as a treatment: stereotactic surgical resection (5 patients) and aspiration of lesions (7 patients). This study confirms the great accuracy and low morbidity of the stereotactic techniques. Computed tomography and magnetic resonance imaging determinate the precise stereotactic coordinates, but in some cases it is necessary to perform stereo-angiography. The stereotactic surgical resection of brain tumors allows the treatment of deep lesions or located at functional areas and considered to be inoperable before. The related literature is discussed.

[Microsurgical treatment of trigeminal neuralgia. A study of 50 cases]. / Traitement microchirurgical de la névralgie du trijumeau. Etude sur 50 cas.

The authors present a study of 50 patients with trigeminal neuralgia treated by posterior fossa microsurgery. Microvascular decompression of the trigeminal nerve was performed in 48 patients. In 2 cases no neuro-vascular compression was found, and a partial rhizotomy was carried out. In 98% of the cases there was postoperative abolition of the pain. Two cases of wound infection and three CSF fistulas were the operative complications. These patients were reoperated and cured. Twenty five patients were reviewed between 13 months and 8 years after surgery. Twenty one remained painfree without any drug, 3 were painfree taking 200 to 400 mg Carbamazepineper day, and 1 patient was reoperated after two years without pain because of recurrence of the neuralgia. There was no mortality or major morbidity in this series. Our results and the literature concerning this method are discussed in this article. In conclusion, microvascular decompression may be indicated in a large number of patients with essential trigeminal neuralgia due to its excellent pain control, no mortality and low morbidity.

Cerebral cysticercosis presenting as mass lesion.

Four cases of cerebral cysticercosis that presented as brain tumor are reported. The diagnosis of these lesions was possible only after the operation. The clinical manifestations of these patients are discussed. The findings on computed tomography scanning as well as the possibilities for differential diagnosis are presented. All the patients were operated on and the diagnosis confirmed histologically. The difficulties encountered at the operations and the alternative methods for the treatment of these lesions are discussed.