Extradural resection of the anterior clinoid process: How I do it.

BACKGROUND: The anterior clinoid process shares a close relationship with the optic canal, the internal carotid artery, the superior orbital fissure and the cavernous sinus. These structures may be involved in diseases whose surgical exposure requires prior clinoid process resection. METHOD: Based on operative cases we describe the different steps of this surgical technique and illustrate our surgical procedure with a video. Dividing the orbito-temporal periosteal fold is a key-step in order to optimize the elevation of the periosteal dural layer at the level of the superior orbital fissure to expose the contours of the anterior clinoid process. The clinoid tip is removed after "debulking" the bony content inside the anterior clinoid process in order to leave only a thin shell of bony contour. The bony shell is then detached from the dura, twisted and pulled out. The indications and limitations of the technique are presented. CONCLUSION: The extradural approach of the anterior clinoid process totally provides a full resection of the anterior clinoid process and safety for the paraclinoid space structures. Meticulous stepwise bony resection and optimized dura opening contribute to reduce the risk inherent to this technique.

Cerebellopontine angle gangliogliomas: Report of two cases.

BACKGROUND: Gangliogliomas are rare tumors of the central nervous system. We report two unusual cases of gangliogliomas located in the cerebellopontine angle (CPA). POPULATION AND METHODS: The first patient was a 57-year-old woman, who presented with dizziness and harbored a non-enhanced heterogeneous mass located in the cisternal space of the CPA. A partial microsurgical removal was performed, and the pathological examination concluded a grade I ganglioglioma according to the WHO Classification. The postoperative course was uneventful without any adjuvant treatment and the 5-year imaging follow-up indicated a stable remnant tumor. The second patient was a 35-year-old male who presented with acute vertigo and imbalance associated with recent prominent headaches; MR imaging showed a large heterogeneous and post-contrast enhanced tumor mass located in the CPA cistern with a mass effect on the brain. An optimal subtotal surgical resection was performed. The pathologists concluded a WHO grade III ganglioglioma. In spite of adjuvant radiotherapy and chemotherapy, the evolution proved unfavorable and patient died from cancer complications within a 2-year period. In both cases, the precise origin of the tumor could not be clearly identified even if the major component was present in the cisternal space. CONCLUSION: Gangliogliomas growing into the cisternal spaces are exceedingly rare particularly in the CPA. Due to its infiltrating behavior and major difficulties to identify the tumor margins, total resection is not routinely feasible. The histological grading is the most important predictor for oncological prognosis.