[Surgical anatomy of the brain stem]

We reviewed the literature on brain stem anatomy, to identify possible and non-hazardous entry zones with a minimum of functional risks. Using the reticular formation defined as a median structure in a coronal plane, we determined six anatomic zones, 3 ventral, 3 dorsal (mesencephalic, pontic, medulla-oblongata). Considering the functional structures surrounding each zone, the possible penetration points are described. There are ventral, one for the mesencephale, one for the pons, one for the medulla oblongata; and dorsal, one for the mesencephale, two for the floor of the 4th ventricle, one for the medulla oblongata.

Kyste lombaire hémorragique juxta-articulaire

We report the case of a hemorrhagic lumbar juxta facet cyst (L2-L3), revealed by a chronic right lumbocruralgia, in a 77-year-old woman treated by anticoagulants for cardiac arrhythmia. Computerized tomography and magnetic resonance imaging suggested the diagnosis of benign tumor. During surgical removal of the whole lesion, a hemorrhagic synovial cyst was evoked. The operation dramatically relieved the symptoms. The diagnosis was confirmed by the histopathological analysis confronted with the clinical and the radiological findings. This uncommon observation allows the discussion of the pathogenic mechanism and of the differential diagnosis.

[Extradural thoracic arachnoid cyst. Case report and review of the literature]

OBJECTIVE

To report an unusual and asymptomatic cause of cord compression treated surgically with good clinical outcome.

METHODS AND MATERIAL

We report a case of extradural arachnoid cyst in the thoracic region and review the literature on the clinical, neuroradiologic and therapeutic features.

RESULTS

A 17-year-old man, with unremarkable past medical history was referred to our institution of Neurosurgery, CHU Mohammed-VI, Marrakech, with progressive spastic paraparesis. Magnetic resonance imaging (MRI) showed a posterior extradural cystic lesion in the thoracic region from T6-T7 thoracic vertebra. The cyst was completely removed by posterior approach. An arachnoid cyst was confirmed at the histological study. Neurological symptoms improved after surgery.

CONCLUSION

Given its infrequency, the diagnosis of arachnoid cyst should be suspected when a cystic lesion causes cord compression. Surgery is the treatment of choice, providing good clinical outcome.

Les kystes dermoïdes de la fosse cerebrale postereure

Matériel et Méthode 3 enfants âgés de 18 mois à 8 ans ont été colligés au service entre 2005 et 2010. Résultas 3 patients ont présenté un syndrome d’hypertension intracrânienne, dont un patient a présenté une méningite récidivante. Tous avaient un sinus dermique. L’IRM a été réalisée dans tous les cas. Tous ont bénéficié d’une exérèse chirurgicale totale et d’une dérivation du LCR par ventriculo-cisternostomie première en urgence dans un cas et par dérivation ventriculo-péritonéale en post-opératoire dans deux cas. L’évolution était satisfaisante sans récidive avec un recul moyen de 3 ans. Conclusion Dans notre série, le KD de la fosse cérébrale postérieure est toujours associé à un sinus dermique et à une hydrocéphalie. La prise en charge repose sur l’exérèse chirurgicale et sur la dérivation du liquide cérébro-spinal.Mots clés : kyste dermoïde, sinus dermique, fosse cérébrale postérieure, chirurgie, résonance magnétique