Marcos Tatagiba

Immunohistochemical detection of female sex hormone receptors in meningiomas: correlation with clinical and histological features.

Sixty-one meningiomas from 60 patients were screened for estrogen receptors and progesterone receptors (PgR) with monoclonal antibodies in an immunohistochemical assay. In addition, 43 of the cases were evaluated for tumor size and peritumoral edema, as seen on computed tomographic scans and magnetic resonance images. Sixty-one percent of the tumors contained significant amounts of PgR, whereas no estrogen receptor-positive tumor was observed. Thirteen percent of all tumors were classified as nonbenign variants (atypical and anaplastic meningiomas) and were more frequently found in male patients (P < 0.05). Nonbenign tumors more frequently showed an absence of PgR (P < 0.05), and there was a tendency for PgR-negative tumors to be larger than PgR-positive ones. No correlation was found between PgR status and edema. It is concluded that PgR status in meningiomas is related to tumor differentiation and may be of prognostic value with regard to biological behavior and clinical outcome.

Intracanalicular acoustic neurinomas.

The cases of 16 patients with acoustic neurinomas confined to the intracanalicular area are presented. These represent 2.7% of the 600 patients with acoustic neurinomas consecutively operated upon at the Neurosurgical Clinic at Nordstadt Hospital during the last 8 years. The comparatively earlier onset of vestibular symptoms and signs was characteristic of this group and precipitated diagnosis. The diagnostic reliability of magnetic resonance imaging was at least equivalent to that of air computed tomographic cisternography. Complete tumor removal was accomplished via the suboccipital approach in all patients, with 100% preservation of facial nerve and facial function; the cochlear nerve was preserved anatomically in 100% of the patients and functionally in 57%. No recurrence has occurred during follow-up periods of up to 8 years in all 16 patients. A broad spectrum of the current literature is considered, and purely intracanalicular acoustic neurinomas are discussed with regard to clinical characteristics, diagnostic steps-including neuroradiological and neurophysiological approaches-and surgical treatment and results.

Trigeminocardiac reflex during skull base surgery: mechanism and management

SummaryBackground. We study the occurrence and management of the trigeminocardiac reflex (TCR) during neurosurgical procedures for lesions of the skull base.Method. Two hundred patients underwent neurosurgical procedures for various skull base lesions and were evaluated retrospectively for the occurrence of the TCR during surgery. This phenomenon was defined as the onset of bradycardia lower than 60 beats/minute and hypotension with a drop in mean arterial blood pressure of 20% or more due to intra-operative manipulation or traction on the trigeminal nerve.Findings. Sixteen patients (8%) had a TCR intra-operatively (7 vestibular schwannomas, 5 sphenoid wing meningiomas, 3 petroclival meningiomas, 1 intracavernous epidermoid cyst).In all 16 patients with a TCR the postoperative courses presented no complications that could be directly related to this intra-operative phenomenon.Conclusions. Due to the intracranial course of the trigeminal nerve several surgical procedures at the anterior, middle and posterior skull base may elicit the trigeminocardiac reflex. Continuous monitoring of hemodynamic parameters allows the surgeon to interrupt surgical manoeuvres immediately upon the occurrence of the TCR. This technique is sufficient for the heart rate and the arterial blood pressure to return to normal levels without the necessity of additional anticholinergic medication.

Peritumoral blood flow in intracranial meningiomas.

Blood flow was measured in intratumoral tissue, the cerebral hemispheres and particularly in the peritumoral area of 12 patients with intracranial meningiomas using the stable xenon-enhanced computed tomographic scan. Tumor blood flow frequently showed a heterogeneous pattern of enhancement with high flow at the tumor periphery and a central area of hypoperfusion. Blood flow values were on average 28% lower in the peritumoral area than in the ipsilateral cerebral hemisphere. In individual cases, blood flow values in the peritumoral edematous area were very low. These findings suggest that the hypodense area surrounding meningiomas does not solely represent vasogenic edema, but may actually represent tumor pressure ischemia.

Surgical Management of High Jugular Bulb in Acoustic Neurinoma Via Retrosigmoid Approach

Of 200 patients with acoustic neurinoma undergoing an operation via the retrosigmoid transmeatal approach in the semisitting position, 18 patients had a high jugular bulb on the tumor side. The frequency was 9%. From a neurosurgical point of view, a jugular fossa above the low border of the internal auditory canal (IAC) is classified as a high one. All 200 patients were evaluated by computed tomography with bone window reconstruction of high-resolution thin axial slices (1.5 mm). High jugular bulbs were classified into three grades as follows: Grade I, jugular bulb situated less than 1.5 mm above the low border of IAC; Grade II, jugular bulb between 1.5 and 3.0 mm above the low border of the IAC; Grade III, jugular bulb > 3 mm above the low border of IAC. There were eight patients with Grade I, six patients with Grade II, and four patients with Grade III. In these patients, in order to open the IAC without concomitant injury of the jugular bulb, the superior posterior portion of the porus was drilled away. Opening the jugular fossa was unavoidable in Grade III cases. No difference was noted in functional preservation of facial or cochlear nerve between HJB cases and normal jugular bulb cases, but HJB cases had a higher frequency of air embolism during tumor removal than did normal cases (16 versus 5%), especially Grade III cases (two of four). There was no mortality or morbidity in the cases of air embolism. Details of the surgical procedure in such cases are discussed.

Meningeal melanocytoma of the C8 nerve root: case report.

A case of a meningeal melanocytoma involving the C8 nerve root is presented. The clinical symptoms and the radiological investigations resembled a neurinoma of the spinal nerve root. Intraoperatively the tumor was seen to be firmly attached to the dural covering of the dorsal nerve root. By using microsurgical technique, complete removal of the tumor with preservation of the ventral nerve root was accomplished. Histological examination revealed a typical meningeal melanocytoma as described by Limas and Tio in 1972. Ten additional cases of previously reported spinal meningeal melanocytomas are reviewed. The importance of differentiating this benign lesion from meningeal malignant pigmented tumors is stressed.

Meningiomas of the Cerebellopontine Angle

Meningiomas of the cerebellopontine angle (CPA) represent a clinically and surgically interesting entity. The opportunity of complete surgical excision and the incidence of impairment of nerval structures largely depend on the tumour biology that either leads to displacement of surrounding structures by an expansive type of growth or to an enveloping of nerval and vascular structures by an en plaque type of growth. As the origin and the direction of growth are very variable, the exact tumour extension in relation to the nerval structures and the tumour origin can be identified sometimes only at the time of surgery. Out of a series of 230 meningiomas of the posterior skull base operated between 1978 and 1993, data of 134 meningiomas involving the cerebellopontine angle are presented. There were 20% male and 80% female patients, age at the time of surgery ranging from 18 to 76 years, on the average 51 years. The clinical presentation was characterized by a predominant disturbance of the cranial nerves V (19%), VII (11%), VIII (67%) and the caudal cranial nerves (6%) and signs of ataxia (28%). 80% of the meningiomas were larger than 30 mm in diameter, 53% led to evident brainstem compression or dislocation and 85% extended anteriorly to the internal auditory canal. Using the lateral suboccipital approach in the majority of cases and a combined presigmoidal or combined suboccipital and subtemporal approaches in either sequence in 5%, complete tumour removal (Simpson I and II) was accomplished in 95% and subtotal tumour removal in 5%. Histologically the meningiotheliomatous type was most common (49%) followed by the mixed type (19%), fibroblastic (16%), psammomatous (7%), hemangioblastic (7%) and anaplastic (2%) types. Major post-operative complications were CSF leakage (8%) requiring surgical revision in 2% and hemorrhage (3%) requiring revision in 2%. While the majority of neurological disturbances showed signs of recovery, facial nerve paresis or paralysis was encountered in 17%, and facial nerve reconstruction was necessary in 7%. Hearing was preserved in 82% with improvement of hearing in 6%. The variability of tumour extension, the implications and limitations for complete surgical excision are discussed along with the experiences from the literature.

Meningeal Melanocytoma of the C8 Nerve Root

A case of a meningeal melanocytoma involving the C8 nerve root is presented. The clinical symptoms and the radiological investigations resembled a neurinoma of the spinal nerve root. Intraoperatively the tumor was seen to be firmly attached to the dural covering of the dorsal nerve root. By using microsurgical technique, complete removal of the tumor with preservation of the ventral nerve root was accomplished. Histological examination revealed a typical meningeal melanocytoma as described by Limas and Tio in 1972. Ten additional cases of previously reported spinal meningeal melanocytomas are reviewed. The importance of differentiating this benign lesion from meningeal malignant pigmented tumors is stressed.

Sporadic unilateral vestibular schwannoma with islets of meningioma: case report.

OBJECTIVE AND IMPORTANCEnVestibular schwannomas with meningioma islets have been rarely reported in the literature; they have been observed only among patients with neurofibromatosis Type II. We present a case of a sporadic mixed tumor in a patient without neurofibromatosis Type II that was not suspected before surgery.nnnCLINICAL PRESENTATIONnA 59-year-old female patient presented with clinical signs of progressive loss of hearing. Her family history did not include evidence of neurological diseases. Magnetic resonance imaging scans revealed a typical unilateral vestibular schwannoma.nnnINTERVENTIONnThe tumor presented with invasion of the surrounding arachnoid membrane, as well as Cranial Nerves VII and VIII. Preservation of the facial nerve with complete removal of the tumor was not possible. Therefore, Cranial Nerve VII reconstruction was performed.nnnCONCLUSIONnThe concomitant occurrence of schwannomas and meningiomas infiltrating the arachnoid membrane might be related to poor clinical outcomes for patients with neurofibromatosis Type II, with respect to preservation of facial and acoustic nerves. Among sporadic schwannomas, this phenomenon is extremely rare.

Samii's essentials in neurosurgery

Approaches to the Orbit: a 360 Degrees View.- Intraoperative Brain Mapping.- Functional Microsurgery of Vestibular Schwannomas.- Preservation and Restitution of Auditory Function in Neurofibromatosis Type 2.- Peripheral nerve entrapment syndromes of the lower extremity.- Hypoglossal-facial nerve anastomosis.- Pituitary Surgery Beyond the Sella.- Endoscopy and thermodiskoplasty: a minimally invasive surgical treatment for lumbar pain.- Full-endoscopic lumbar and cervical surgery for disc herniation.- Mini-open transforaminal lumbar interbody fusion for degenerative diseases.- Spinal robotics.- Sphenoid wing meningiomas.- Proliferation Behaviour in Meningiomas.- Syringomyelia and Syringobulbia.- Neural transplantation and restoration of motor behavior in Parkinsons disease.- Potential and limitations of chronic high-frequency deep-brain stimulation in parkinsons disease.- Arachnoid cysts of the posterior fossa.- Surgical reconstruction of musculocutaneous nerves in traumatic brachial plexus injuries.- Facial pain - diagnosis and therapy.- Microvascular Decompression (MVD) for Trigeminal Neuralgia (TN).- Spinal Intramedullary Tumors.- Bypass and vascular reconstruction for anterior circulation aneurysms.- Cerebral bypass and vascular reconstructions for posterior circulation aneurysms.- Facial and cochlear nerve function after surgery of cerebellopontine angle meningiomas.- Optic nerve sheath meningiomas.- Chordomas and Chondrosarcomas.- Vestibular Schwannoma: current state of the art.- Retrosigmoid approach to the posterior and middle fossae.- Endoscope-assisted Microsurgery.- Preoperative visualization of the facial nerve using diffusion tensor imaging fiber tracking in patients with large vestibular schwannomas.- Endoscopic transnasal surgery for clival chordoma.- Olfactory Groove Meningiomas: Pitfalls and surgical technique.- Malformation.- Diagnosis and treatment of adult hydrocephalus.- Petroclival Meningiomas Diagnosis, Treatment and Results.- The surgical management of trigeminal schwannomas.- Facial nerve schwannomas.- Surgery of large and giant residual/recurrent vestibular schwannomas.- Jugular foramen tumors - Diagnosis and management.- Navigated Semirobotic Pedicle Screw Placement - Experience with 250 Consecutive Cases.- Total Lumbar Facet Replacement - Indication, Technique and 3-Years Results.- The Virtual Operating Field - How Image Guidance became integral to microneurosurgery.- Primary Tethered Cord Syndrome.- Considerations on Experimental Neuromodulation Following Grafting the Spinal Cord to Skeletal Muscles for Clinical Application.- Surgery of Cerebellopontine angle Epidermoids.