[Direct transnasal approach. Description and feasibility in 60 patients]. / La voie transnarinaire directe. Description et faisabilité à propos de 60 cas.

BACKGROUND AND PURPOSE: The direct transnasal approach is a less invasive approach to the sella turcica and represents an alternative to the sublabial transsphenoidal approach with minor oro-nasal complications. In this study, we describe this approach with emphasis on post-operative course. METHODS: We studied retrospectively 60 patients operated on consecutively by a transnasal approach between January 1996 and December 2000. RESULTS: There were 47 macroadenomas, 9 microadenomas and 4 non-adenomatous pathologies. Despite its narrowness, the transnasal approach was possible in all cases and allowed tumor removal as satisfactory as with the sublabial approach. Eight patients had complications not directly related to the approach: 1 death (meningitis with brain stem ischemia), 3 pituitary fossa hematomas, 4 rhinorrheas and 2 meningitis. Seven patients had complications related to the approach: 2 nasal obstructions, 1 nasal dryness, 2 sinusitises and 2 hyposmias. All these local complications were transitory and disappeared within 3 months. CONCLUSIONS: In our experience, the direct transnasal approach is safe, quick and less invasive than the sublabial approach.

[Image-guided neuroendoscopy]. / Neuroendoscopie guidée par ordinateur.

BACKGROUND AND PURPOSE: By definition, image-guided neuroendoscopy is a connection between a neuroendoscope and a neuronavigational system creating a computer-guided instrument. Our objective was to adapt our rigid endoscope with our neuronavigation system to perform computer-guided endoscopy. METHODS AND RESULTS: The rigid neuroendoscope, equipped with light emitting diodes, was connected to the work station. We report our early results with this device in 17 patients: 8 ventriculocisternostomies, 5 ventriculocisternostomies with biopsies of tumors of the posterior part of the third ventricule, 4 biopsies or tumor removal like colloid cysts. No technical complications were encountered. CONCLUSIONS: The development of image-guided neuroendoscopy has modified our approach to neuroendoscopy because the surgical procedure is facilitated. The use of fluoroscopy becomes unnecessary. The surgeon can choose, independent of the preestablish surgical technique, the entry point, the target and, of course, the optimal trajectory. The technique is adaptable to the individual anatomy of each patient, the location and the nature of the target. It is an undeniably useful teaching tool and represents a real progress in minimally invasive neurosurgery.

[Adenoid cystic carcinomas invading the skull base. Apropos of 4 cases and review of the literature]. / Carcinomes adénoïdes kystiques envahissant la base du crâne. A propos de 4 observations et revue de la littérature.

Head and neck adenoid cystic carcinomas may invade the adjacent skull base by bone lysis and/or by perinervous and perivascular spread within the skull base foramina. Neurosurgical decision making is not well defined regarding the extent of intracranial tumor component removal, as neurosurgical expertise is limited for this peculiar type of tumors. The issue is to decide whether a radical supposedly locally curative surgery should be attempted, or if a large non disfigurating surgery is mandatory, keeping in mind the frequency of local recurrences and of distant metastases. Over a 13-year period, four adenoid cystic carcinomas invading the skull base were operated on at our institution: two tumors originated in the parotid gland, one in the sphenoid sinus, and one in the ethmoid sinus. Surgical removal was total in one case, subtotal in three cases. Post-operative irradiation was delivered in the four patients (two neutron irradiation, two conventional). One patient with advanced metastatic disease was submitted to chemotherapy. Three patients died from local tumor progression and distant metastases within three years after the intracranial tumor extension has been diagnosed. The patient with an ethmoid tumor is still alive seven years after surgery without any evidence of local tumor progression nor distant metastases. Surgery remains the gold standard treatment for adenoid cystic carcinomas invading the skull base. However, in our opinion a large tumor removal, without or with bone osteotomies, but without sacrifice of cranial nerves, cavernous sinus, internal carotid artery, and of the orbit allows patient survival with an acceptable comfort and absence of psychological distress due to disfigurating surgery nor surgically induced neurological functional deficit. Post-operative irradiation may sometimes stabilize locally the lesions. The place of chemotherapy has, yet, to be determined.

Trans-sinusal frontal approach for olfactory groove meningiomas.

The authors report on their experience with the trans-sinusal frontal approach in removing olfactory groove meningiomas. Six tumors were operated on by the trans-sinusal frontal approach, using a bicoronal incision; two tumors developed on one side, and there were four bilateral olfactosellar tumors. Osteotomy of the anterior wall of the frontal sinus was performed with an oscillating saw without any burr hole. The posterior wall of the sinus was resected and the tumor was attacked through a real subfrontal route along the plane of the anterior skull base. Ethmoidal blood supply was controlled at the initial stages of the operation, allowing avascular tumor debulking. Olfactory nerves, invaded by the tumor, were removed along with the tumor. Tumor extensions toward the sella and the optic canals were removed without brain retraction, opening of the Sylvian fissure, or dissection of the carotid arteries. All patients made a good neurologic recovery; intellectual impairment disappeared within 1 month, and visual acuity normalized within 2 weeks. Olfactory nets were preserved on the contralateral side in unilateral tumors. The trans-sinusal frontal approach is technically easy and safe to achieve. Osteotomy and replacement of the anterior wall of the frontal sinus are rapidly performed. When the frontal sinus is small, imageguided surgery allows precise deliniation of its limits and the free bone flap, including the calvarial outer layer, tangentially cut from one supraorbital canal to the other. The cosmetic result is perfect, as the normal contour of the forehead is maintained without any scar or visible burr hole. The trans-sinusal frontal approach gives access to the orbital roofs and to the central anterior skull base from the crista galli to the tuberculum sellae and the anterior clinoid processes. The trans-sinusal frontal approach represents an alternative to conventional craniotomies for tumors developed in the central anterior skull base, especially for olfactory groove meningiomas, whatever their size.

[Epidermoid cyst of the lateral ventricles]. / Kyste épidermoïde des ventricules latéraux.

A case of epidermoid cyst of the lateral ventricles is reported. The patient presented with a weakness of the left lower limb and neuropsychological disorders. The diagnosis was assessed by CT scan and MRI, and confirmed at the operation. The lesion has been largely removed through a transcallosal approach though incompletely. However the long term follow-up was uneventful. Twenty-nine cases of the literature have been reviewed.

[Frontal sinus approach to olfactory groove meningiomas]. / Voie trans-sinusienne frontale pour les méningiomes de la gouttière olfactive.

We report on our experience of the frontal sinus approach for removing olfactory groove meningiomas. Five tumors were operated on, one unilateral, four bilateral. Osteotomy of the anterior wall of the frontal sinus was performed with an oscillating saw without any burr hole. The posterior wall of the sinus was resected and the tumor was attacked along the plane of the anterior skull base. Ethmoidal blood supply was controlled at the initial stage of the operation, allowing avascular tumor debulking. Olfactory nerves, invaded by the tumor, usually cannot be spared. Tumor extensions towards the sella and the optic canals were removed without any brain retraction, nor opening of the sylvian fissure, nor dissection of the carotid arteries. The frontal sinus approach is technically easy to achieve. Osteotomy and reconstruction of the anterior wall of the frontal sinus are rapidly performed. When the frontal sinus is small, image guided surgery allows to delineate precisely its limits and the flap includes the calvarial outer layer, tangenitally cut from one supra-orbital canal to the other. Cosmetic result is perfect. The frontal sinus approach gives access to the medial part of the orbital roofs and to the central anterior skull base from the crista galli to the tuberculum sellae and the anterior clinoids. The frontal sinus approach represents an alternative to conventional craniotomies for tumors developed in the central anterior skull base, especially for olfactory groove meningiomas.

[Postero-lateral surgical approach to soft cervical herniated discs. Technical note]. / Abord postéro-latéral des hernies discales cervicales molles. Note technique.

Most ruptured cervical discs are operated on by an anterolateral approach. The posterior approach is an older procedure, nowadays underused because it was associated with a high morbidity, especially in terms of medullary complications. However, posterior approach has evolved in posterolateral route, which is not so devastating and has a very low morbidity rate. It gives excellent functional results when surgery is dedicated to monoradiculopathy from soft posterolateral cervical hernias. It seems appropriate to consider this surgical route as an alternative to anterolateral surgery in these very selected cases. The authors describe and comment the technique.

Venous reconstruction in surgery of meningiomas invading the sagittal and transverse sinuses.

SURGERY OF MENINGIOMAS INVOLVING MAJOR DURAL SINUSES LEAVES THE SURGEON CONFRONTED WITH A DIFFICULT DILEMMA: leave the fragment invading the sinus in place and have a higher risk of recurrence, or attempt a total removal with or without venous reconstruction and expose the patient to a potentially greater operative danger. The authors report a series of 47 meningiomas (41 of the sagittal sinus, 4 of the transverse sinus and 2 of the torcular) in whom gross total removal was achieved in all cases, and venous reconstruction (of various types) attempted in a majority. Thirty-nine patients had a good outcome and resumed their previous activities. There was a permanent neurological deficit in five due to infarction secondary to injury of central veins (all in the sagittal sinus midthird). Three patients died from brain swelling; all with meningioma totally occluding the sinus and in whom resection was achieved without sinus reconstruction. There were two recurrences in this series which has a mean follow-up of 7.5 years.The authors' surgical experience led them to favor whenever possible, total removal with sinus reconstruction, using a patch for meningiomas with partial sinus invasion and a venous bypass for those with total sinus occlusion.

Experimental models in interventional neuroradiology.

Various experimental models have been developed to test interventional neuroradiologic techniques. Most have been used to test various devices and embolic materials, and a small number of models have been designed for teaching or training purposes. Experimental models in endovascular techniques have seldom been used to stimulate disease processes in order to facilitate their understanding.