Intradural epidermoid cysts of the cerebellopontine angle: diagnosis and surgery.

We report on our recent experience with epidermoid cysts in the cerebellopontine angle. We operated on nine patients since 1985, seven of which were investigated with magnetic resonance imaging. Since the arrival of modern neuroimaging, large lesions can be found with only discrete symptoms, such as isolated tinnitus or unspecific headache. With computed tomography and magnetic resonance imaging, preoperative diagnosis was achieved for most patients; sometimes, however, epidermoid cysts may be very similar to arachnoid cysts. Surgery is the only possible treatment. The decision to operate should be carefully discussed for each patient, particularly if the patient is asymptomatic. The extent of the lesion at the anterior aspect of the brain stem, and sometimes above the tentorium cerebelli, fragile cortex, and vessels, and hazards of postoperative chemical meningitis often make such surgery difficult. The surgeon should not attempt total removal of the cyst membrane. Most patients who undergo surgery, however, recover well, with no or few sequelae. With a mean 3-year follow-up, no recurrence occurred, despite partial removal, as a result of the peculiarly slow growth of these lesions.

Strategy of craniofacial reconstruction after resection of spheno-orbital "en plaque" meningiomas.

Surgical resection of spheno-orbital "en plaque" meningiomas should be as complete as possible to prevent tumor recurrence and therefore requires a bone reconstruction. We report a series of 20 patients operated on for spheno-orbital "en plaque" meningioma between 1981 and 1993. The surgical treatment included a resection of the involved dura and a wide resection of tumoral bone using a fronto-temporal craniotomy extended to the orbitozygomaticomalar bone ridge. The craniofacial reconstruction was performed in the same operative procedure using iliac bone autograft in 11 patients, internal cortical bone from the bone flap in 8 patients, and a coral graft in 1 patient. The cosmetic result was scored according to the following criteria: superior frontal paralysis, appearance of the orbitomalar bone ridge, shape of the external temporal fossa, and projection of the eyeballs. The cosmetic result was scored as excellent or good in 17 patients, average in 2 patients, and poor in 1 patient. The iliac bone autograft appeared to be the best material for craniofacial reconstruction because it could be modeled easily to the desired shape. However, the reconstruction technique was modified as necessary according to the extent of tumor removal, clinical presentation, and age of the patient.

A frameless stereotaxic localisation system using MRI, CT and DSA.

The authors present a method of stereotaxic localisation using magnetic resonance imaging (MRI) computerized tomography (CT) and digital subtracted angiography (DSA) which does not require localisation frams fixed to the patient's skull, but uses only four cranial landmarks corresponding to the holders of the neurosurgical stereotaxic frame. The method presents no major constraints in routine examinations. The geometrical distortions of the imaging devices are corrected. Three-dimensional localisation is performed using sagittal and axial slices in MRI, axial slices in CT and only two associated frontaly and lateral views in DSA. The images data are transferred to a PC-based system. By locating the landmarks on the images, the transformation matrixes can be computed to obtain the 3D coordinates of a target in the stereotaxic space and in any imaging modality. The results obtained show the precision of the corrections and the millimetre accuracy of pin-point target localisation.

[Magnetic resonance imaging of the facial nerve in a case of Melkerson-Rosenthal syndrome]. / Imagerie par résonance magnétique du nerf facial dans un cas de syndrome de Melkerson-Rosenthal.

A 35-year-old man treated for a Crohn's disease presented with a second facial palsy in a setting of recurrent labial edema known since childhood. The diagnosis of Melkerson-Rosenthal syndrome was established. MRI showed a small T1 gadolinium-enhanced lesion of the facial nerve suggesting an inflammatory process. Similarities of pathologic lesions found in Melkerson-Rosenthal syndrome, Crohn's disease and sarcoidosis raise the question of the relationships between these disorders.

[Neurologic emergencies]. / Les urgences neurologiques.

Neurological symptoms are a very frequent cause of consultation in emergency units and require consultation with neurologists and neuroradiologists. The most frequent diagnoses are stroke syndrome, seizure, headache, confusion, meningitis and meningo-encephalitis, and facial palsy. The morbidity and mortality of neurological emergencies are strongly related to prompt medical management of the patients which often requires neuroimaging studies. The most common neurological emergencies will be reviewed.

[Identification of the central sulcus using the scanner and MRI]. / Repérage du sillon central en scanner et en IRM.

Methods to directly and indirectly identify the central sulcus are presented. In the axial plan, direct method is remarkable but obviously requires good visualization of the sulci in the central region. Sulci are readily visible in 90% of the cases on CT scans and in 50% of the cases on MRI. The method can also be applied when tumoral development erases the cerebral sulci by direct lecture of the controlateral rolandic region and right-left transfer. Within the precision limits of the method, it can be considered that the central sulci are symmetrical. The main signs are: the relative morphologies of the superior frontal sulcus and the precentral sulcus, the hook-shaped aspect of the middle part of the central sulcus, the internal end of the central sulcus projection anteriorly to the pars marginalis, the bifid nature of the internal end of the posterior central sulcus contouring the pars marginalis, and the lesser thickness of the posterior central gyrus compared with the precentral gyrus. The indirect method is less precise and is used when the direct method is unsuccessful. The central sulcus is identified on the sagittal images and, using the lateral view of the skull as a reference image, the topographic information is transferred to the axial images.

[Nasofrontal dermoid fistulae and cysts. Apropos of 19 cases]. / Les fistules et kystes dermoïdes naso-frontaux. A propos de 19 cas.

A series of 19 children with congenital nasal dermoid cyst or fistulas admitted in our department between 1978 and 1992 was reviewed in a retrospective study. They were 8 females and 11 males, ages ranged from 9 months to 7 years (mean: 2 years and 4 months). At diagnosis 8 children presented with infection (superficial in 6 cases, neurological in 2 cases), and in 11 cases the malformation was discovered by the family physician. In 14 cases the cyst was located at the mid nasal ridge. Four children had associated malformations: neurodevelopmental delay (2 cases), hypertelorism (1 case) and external ear agenesia with facial palsy. The cyst was subcutaneous in 5 cases and was operated on through a nasal approach. The 14 other children were operated through associated intra and extracranial approaches. Surgical exploration disclosed a dural extension of the fistula in 9 cases. When performed, preoperative radiological explorations including CT Scan and/or MRI had not always predicted the dural extension. The mean follow-up is 5.3 years. No recurrence was recorded and the cosmetic result was always excellent. Preoperative radiological investigations are necessary to precise the location of these malformations and to detect associated disorders, but they appear unable to prove the extension of the fistula to the dura. Intracranial and extracranial approaches should be always planned to perform a total excision of the lesion.

[Long-term results of the surgical treatment of spheno-orbital osteomeningioma]. / Résultats à long terme du traitement chirugical des ostéo-méningiomes sphéno-orbitaires.

The authors report a series of 21 cases of spheno-orbital "en plaque" meningiomas operated on between 1981 and 1993. All patients underwent surgery via fronto-temporal approach with orbito-zygomatic removal, followed by bone reconstruction. A complete tumor resection was performed in 15 cases. In the remaining patients, tumor resection remained subtotal, as the cavernous sinus was involved. Histological examination disclosed a low grade meningioma in 17 cases, high grade meningioma in the other patients. Radiation therapy was performed in 5 patients, when the tumoral resection was incomplete or for high grade meningiomas. The mean follow up was 7 years. One patient died in the post-operative course. Transient ophthalmoparesis occurred in 9 cases, 2 patients had pre-operative oculomotor palsy related to tumoral extension in the cavernous sinus and remained unchanged. Visual acuity remained unchanged after surgery in all patients who presented with normal visual acuity. It was unchanged or improved in 63% of patients who presented with moderate visual impairment. Despite the extent of the bone resection, the cosmetic results were good or excellent in 75% of patients, fair in 17%, and bad in 8%. Recurrence of the tumor occurred in 3 patients, with high-grade meningiomas (2 cases) or after subtotal removal of a low-grade meningioma (1 case). Orbito-fronto-temporal approach is necessary to complete the resection of the tumor extended in the orbit, the orbital fissures or the optic canal. Early operation allows a complete tumor resection before the tumor extends to the cavernous sinus.

[Frontal sinus osteomas: neuro-ophthalmological complications]. / Complications neuro-ophtalmologiques des ostéomes des sinus frontaux.

Osteomas are the most frequent benign tumors of the paranasal sinuses. They often grow in the frontal sinus near the nasofrontal duct. They remain frequently asymptomatic and they tend to be an incidental finding on radiographic studies. Rarely, they extend out of the sinus limits. Two cases with neuro-ophthalmological complications are reported and discussed. A 19-year-old female presented with a progressive left visual impairment and orbital bone deformity. A CT-scan revealed a large calcified mass in both frontal sinuses, with left intraorbital and frontobasal extension. A 21-year-old man suffered from acute frontoethmoidal sinusitis. Radiological exams revealed a right frontal sinus osteoma with bilateral nasofrontal ducts obstruction. The frontal sinus cavities were filled with a large mucocele with intracranial extension. Both patients were successfully treated using frontobasal craniotomy with complete osteoma and mucocele removal and cranio facial bone reconstruction. Neuro-ophthalmological or intrasinusal complications of osteomas lead to radical treatment. CT-scan and MRI analysis for surgical purpose and strategy are emphased.

[Infectious temporomandibular arthritis. Apropos of a case in an adult]. / Arthrite infectieuse temporo-mandibulaire. A propos d'un cas chez l'adulte.

Imagery revealed osteitis of the base of the skull in a 37-year-old patient with infectious arthritis of the temporomandibular joint. The characteristics of this rare pathology were recalled from a review of the literature.

[The first clinical application of the vestibular orientation of the head using a scanner, in children presenting with asymmetry]. / Premières applications cliniques de l'orientation vestibulaire de la tête par scanner, chez des enfants présentant une asymétrie.

Digitalized imaging now allows determination the "medio-labyrinthic" plane to analyse cephalic symmetry. It is constructed from the two "vestibions", central points of the rings of lateral semi-circular canals. Reconstruction parallels this plane, passing through the vestibions provide vestibular orientation, with effective and constant coïncidence between right and left directions. That being obtained, it is easy to visualise orientation of the entire cephalic region in the three incidences of "vestibular space", and to work out sections parallels to the three vestibular planes, allowing analysis of the symmetry of the studied elements.

Marchiafava-Bignami disease: use of contrast media in CT and MRI.

We report two cases of Marchiafava-Bignami disease studied by CT and MRI. Both patients displayed persistent confusion and a disconnection syndrome but had a favourable outcome. In both cases, CT with intravenous contrast medium revealed enhancement of the corpus callosum in the early stage. MRI showed gadolinium uptake in both the genu and splenium of the corpus callosum in one case, 8 days after the onset. Three weeks after admission, cystic lesions appeared in the corpus callosum on MRI T1-weighted sagittal images in both cases. Contrast medium uptake may be useful in the diagnosis of Marchiafava-Bignami disease.

[A technic using MRI. A comparative study of 3 anesthetic technics of the inferior alveolar nerve]. / Approche en I.R.M. D'une etude comparative de 3 techniques d'anesthesie du nerf alveolaire inferieur.

In our study we used M.R. sectional imaging in the axial and coronal planes to investigate three alveolar nerve anaesthesia techniques: Gow Gates, Akinosi and Classical techniques. Furthermore, anatomic sections were made using cadaveric specimens in axial and coronal planes to visualize anatomical relations of the anaesthetic drug. The present study showed the more or less important and quick spreading of the anaesthetic drug through the infra temporal area depending on the anaesthesia technique. Possible incidents are also discussed.