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Rabih Hage,1 Claire Alapetite,2 Hervé Brisse,3,4 Kevin Zuber,5 Augustin Lecler,6 Guillaume Lot,7 Caroline Le Guerinel,7 Catherine Vignal-Clermont,1 Herve Boissonnet7 1Neuro-ophthalmology Department, Hôpital Fondation A. de Rothschild, Paris, France; 2Radiation Oncology Department, and Proton Center Institut Curie, Paris-Orsay, France; 3Imaging Department, Institut Curie, Paris, France; 4Université des Sciences et Lettres, Paris, France; 5Department of Statistics and Clinical Research, Hôpital Fondation A. de Rothschild, Paris, France; 6Radiology Department, Hôpital Fondation A. de Rothschild, Paris, France; 7Neurosurgery Department, Hôpital Fondation A. de Rothschild, Paris, FranceCorrespondence: Rabih Hage Tel/Fax +33148036322Email rhage@for.parisPurpose: Management of optic nerve sheath meningiomas (ONSM) remains challenging. Photon radiation therapy (PhRT) is the most common treatment for sight-threatening ONSM. Proton beam therapy (PBT) is less commonly used because it is more expensive and because there are questions about its efficacy specifically in relation to ONSM. PBT has the theoretical advantage of reducing radiation exposure to adjacent structures. We report the visual outcome of patients with primary ONSM managed at the Fondation Ophtalmologique Adolphe de Rothschild, Paris, France, and treated with PBT at the Centre de Protonthérapie, Institut Curie, Orsay, France.Methods: We conducted a retrospective review of all patients with primary ONSM who received PBT (either by itself or following surgery) between January 2006 and January 2019. Neuro-ophthalmic examinations were performed at presentation and after radiotherapy, and, when applicable, after surgery. Meningiomas were measured at the time of diagnosis and at each follow-up MRI examination.Results: Sixty patients (50 women, 10 men; mean age, 45.2± 11.1y) were included, of whom 29 underwent surgery. At presentation, 52 (87%) of them had decreased vision (average visual acuity: 0.6 logMAR). Fundus examination showed optic disc swelling (n=27; 46.5%), optic disc pallor (n=22; 37.9%), optic disc cupping (n=2; 3.4%), opto-ciliary shunt (n=8; 13.8%), or choroidal folds (n=5; 8.6%). Otherwise, it was unremarkable (n=7; 12.1%). After treatment, visual function was stable overall. Fundus examination showed pallor (n=47; 83.9%), swelling (n=3; 5.4%), or cupping (n=2; 3.4%) of the optic disc, or was unremarkable (n=5; 8.9%). The visual field of 8 patients worsened, while 3 developed asymptomatic retinal hemorrhages. Tumor shrunk significantly in 8 patients at 1 year after PBT and remained stable in size in all others. Patients with opto-ciliary shunts had significantly worse visual outcome than other patients. Retinal abnormalities were observed in 11 patients during follow-up.Conclusion: PBT alone or in association with surgery appears to be a safe and efficient treatment for ONSM, reducing the tumor size and stabilizing visual function. The risk of developing radiation retinopathy seems to be higher when patients had upfront surgery.Keywords: optic nerve sheath meningioma, ONSM, proton beam therapy, PBT, compressive optic neuropathy, brain tumor, visual loss, opto-ciliary shunt, radiation retinopathy, RON

Objectives: The objective of our study is to take stock of the cranioplasty implants used within our establishment., Materials and Method: We analyzed the patients files who underwent craniectomy followed by cranioplasty between 2017 and 2023, with at least 1 year of follow-up after cranioplasty (n=75). The data were extracted from the computerized patient file (DxCare®, Dédalus) and the pharmaceutical management tool for drugs and sterile medical devices (Pharma®, Computer Engineering). The sex ratio, indication for craniectomy, operating time, time between craniectomy and cranioplasty, complications and aesthetic result were statistically analyzed., Results: The main indications are stroke (n=59; 78.5%) and aneurysms (n=7; 9.5%). Among the 75 patients, 52 benefited from the placement of a custom implant (PolyEtherEtherCetone/PEEK or Hydroxyapatite) and 23 from cementoplasty. The operating time was significantly shorter (P<0.05) for custom cranioplasty (1.93±0.61h vs. 1.62±0.53). Only 4 patients (5.3%) were not satisfied with the aesthetic result following the placement of a custom implant. A greater risk of infection was found in the context of cementoplasty (43% for cementoplasties vs. 25% for the custom implant, so χ 2 (P=0.1095), this difference not being statistically significant., Conclusion: This collaborative work between the pharmacy and the adult neurosurgery department served to establish an initial register for monitoring patients who have undergone cranioplasty for whom the ideal implant remains to be determined., (Copyright © 2024. Published by Elsevier Masson SAS.)

Background: Ruptured middle cerebral artery aneurysm (MCAa) can lead to intracerebral hematoma, and surgical evacuation can be performed in these cases. MCAa can be treated by clipping or before by endovascular therapy (EVT). Our objective was to compare the impact on the functional outcome of MCAa in patients with intracerebral hematoma requiring evacuation., Methods: This is a multicenter, retrospective, cohort study with nine French neurosurgical units from January 1, 2013, to December 31, 2020. All participants were adult patients who required evacuation of an intracerebral hematoma. We looked for risk factors for poor outcomes by comparing the baseline characteristics and treatments performed by using the 6-month modified Rankin scale score. Poor outcomes were defined by an modified Rankin scale score of 3-6., Results: A total of 162 patients were included. A total of 129 (79.6%) patients were treated by microsurgery, and 33 (20.4%) patients were treated by EVT. In multivariate analysis, factors associated with poor outcomes included hematoma volume, realization of a decompressive craniectomy, occurrence of procedure-related symptomatic cerebral ischemia, occurrence of delayed cerebral ischemia, and EVT. In the propensity score matching analysis (n = 33 per group), poor outcomes were observed in 30% of the patients in the clipping group versus 76% in the EVT group (P < 0.001). These differences may have been related to a longer delay between hospital admission and hematoma evacuation in the EVT group., Conclusions: In the specific subgroup of ruptured MCAa with intracerebral hematoma that requires surgical evacuation, clipping with concomitant hematoma evacuation could provide better functional outcomes than EVT followed by surgical evacuation., (© 2023. Springer Science+Business Media, LLC, part of Springer Nature and Neurocritical Care Society.)

Objective: Middle cerebral artery aneurysms (MCAAs) have been considered good candidates for microsurgery. Our objective was to evaluate the risk of complications and the risk factors for complications with microsurgical treatment of MCAAs to better define the indications for microsurgery., Methods: We conducted a retrospective cohort study from 3 tertiary neurosurgical units from January 2013 to May 2020. We evaluated the frequency of complications and searched for the risk factors for complications after microsurgery. Complications were defined as a composite criterion with the presence of one of the following: procedural-related death, symptomatic cerebral ischemia, impossible exclusion, incomplete exclusion, or rebleeding of the treated aneurysm and symptomatic surgical site hematoma., Results: A total of 292 MCAAs were treated, with 29 complications (9.9%), including symptomatic cerebral ischemia (4.8%), aneurysm rebleeding (0.3%), surgical site hematoma (1.0%), impossible exclusion (0.3%), and incomplete exclusion (4.1%). Severe complications, defined as death or a modified Rankin scale score of ≥4 at 3 months, were infrequent, occurring in 7 of the 292 patients (2.4%). On multivariate analysis, the risk factors were a ruptured aneurysm, a larger maximum aneurysm size, a larger neck size, and arterial branches passing <1 mm from the aneurysm neck or dome., Conclusions: Microsurgical management of MCAAs can be performed with very low morbidity rates. In some cases, at least for factors that do not result in significant difficulty for endovascular therapy, such as the presence of an en passage artery or ruptured aneurysm, endovascular therapy can be considered to be as safe and effective as clipping., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Objectives: We aimed to study the potential clinical relevance of 9p allelic loss, with or without copy number variation, in 1p/19q codeleted anaplastic oligodendroglial tumors (AOTs)., Methods: This study enrolled 216 patients with 1p/19q codeleted AOT. The prognostic value of 9p allelic loss was investigated using a French nation-wide prospective registry, POLA (prise en charge des tumeurs oligodendrogliales anaplasiques) and high-density single nucleotide polymorphism arrays. We validated our results using the Repository of Molecular Brain Neoplasia Data (REMBRANDT) dataset., Results: The minimal common region of allelic loss in chromosome arm 9p was 9p21.3. Allelic loss of 9p21.3, detected in 41.7% of tumors, was associated with shorter progression-free and overall survival rates in univariate (p = 0.008 and p < 0.001, respectively) and multivariate analyses (p = 0.009 and p = 0.009, respectively). This finding was validated in the REMBRANDT dataset in univariate and multivariate analysis (p = 0.01 and p = 0.01, respectively)., Conclusion: Our study highlights a novel potential prognostic biomarker in 1p/19q codeleted AOT. Further prospective studies are warranted to investigate our finding., (© 2015 American Academy of Neurology.)

Orbital manifestations occur in less than 1% of patients with neurofibromatosis type 1 (NF1). These manifestations are frequently associated with sphenoid wing dysplasia. The typical radiologic feature is partial or total loss of the greater wing of the sphenoid bone, which leads to herniation of the temporal lobe through the orbital cavity resulting in proptosis and pulsating exophthalmos. Traditional reconstruction of this bone defect involves split bone grafting or titanium mesh. However, these techniques have some limitations due to bone resorption and infection risk. We report the use of 0.85 mm titanium-reinforced porous polyethylene implant sheet in three cases of orbital neurofibromatosis with sphenoid dysplasia. The role of this material was to create a barrier between the brain and orbital cavity. The implant sheet was modeled intraoperatively to reconstruct the orbital cavity anatomy and fitted without any screws. The malleability of the implant allows quick reconstruction of the curved orbital skeleton. Furthermore, the implant doesn't interfere with postoperative imaging and may decrease risk infection., (Copyright © 2014 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.)

Anaplastic oligodendrogliomas (AOD) are rare glial tumors in adults with relative homogeneous clinical, radiological and histological features at the time of diagnosis but dramatically various clinical courses. Studies have identified several molecular abnormalities with clinical or biological relevance to AOD (e.g. t(1;19)(q10;p10), IDH1, IDH2, CIC and FUBP1 mutations).To better characterize the clinical and biological behavior of this tumor type, the creation of a national multicentric network, named "Prise en charge des OLigodendrogliomes Anaplasiques (POLA)," has been supported by the Institut National du Cancer (InCA). Newly diagnosed and centrally validated AOD patients and their related biological material (tumor and blood samples) were prospectively included in the POLA clinical database and tissue bank, respectively.At the molecular level, we have conducted a high-resolution single nucleotide polymorphism array analysis, which included 83 patients. Despite a careful central pathological review, AOD have been found to exhibit heterogeneous genomic features. A total of 82% of the tumors exhibited a 1p/19q-co-deletion, while 18% harbor a distinct chromosome pattern. Novel focal abnormalities, including homozygously deleted, amplified and disrupted regions, have been identified. Recurring copy neutral losses of heterozygosity (CNLOH) inducing the modulation of gene expression have also been discovered. CNLOH in the CDKN2A locus was associated with protein silencing in 1/3 of the cases. In addition, FUBP1 homozygous deletion was detected in one case suggesting a putative tumor suppressor role of FUBP1 in AOD.Our study showed that the genomic and pathological analyses of AOD are synergistic in detecting relevant clinical and biological subgroups of AOD.

Background: External ventricular drainage (EVD) is a freehand neurosurgical procedure performed routinely using the anatomical landmarks., Objective: The aim of this study was to determine the accuracy of EVD catheter freehand placement., Materials and Methods: Pre-operative and post-operative computed tomography scans for 66 consecutive EVDs performed in 56 adult patients (26 men, 30 women) in 2008 were retrospectively reviewed. Etiologies of acute hydrocephalus were subarachnoid or intraventricular haemorrhage (43 cases) or miscellaneous (13 cases). Pre-operative lateral ventricular volume, position of the burr hole, length of the catheter and its sagittal and coronal angular variations from a theoretical trajectory were measured., Results: The EVD was placed on the right (53 cases) or left (13 cases) side. The mean pre-operative lateral ventricular volume was 51 cc (10-118 cc). The average distance from the burr hole to the midline was 28 mm (10-49 mm) and to the supra-orbital ridge was 101 mm (75-125 mm). The mean intracranial catheter length was 60 mm (from 39-102 mm). Only 50% of the EVDs in the coronal plane and 40% in the sagittal plane were placed with an angular variation of ±5° to the target. The tip was placed outside of the ventricles in three cases; 13 catheters crossed the midline, and five intracranial minor haemorrhages were detected., Conclusion: Freehand placement of EVDs does not have sufficient accuracy and may lead to drainage dysfunctions. This data suggests that a guidance system for EVD's would be required.

Primitive neuroectodermal tumors (PNETs) are aggressive neoplasms composed predominantly of undifferentiated cells that show evidence of neural differentiation. Although their classification remains disputed, PNETs are recognized as primary tumors in both the central and peripheral nervous systems. These rare tumors usually occur in children or young adults and are typically metastatic to the spinal cord. The authors report the case of a 70-year-old man with no significant medical history, in whom a peripheral PNET was demonstrated that, based on clinical and imaging findings, manifested as a nonspecific intrathecal tumoral process arising from the cauda equina. Although this lesion is rare in the elderly, the authors' case illustrates the importance of making this diagnosis as early as possible so that a treatment plan may be devised. The use of chemotherapy in association with radiotherapy in relation to the resection of the tumor should be reconsidered.

Acute ischemic infarction of the posterolateral bulbomedullary junction occurred in a 28-year-old man who underwent arterial embolization for the treatment of an intracranial dural arteriovenous malformation. The migration of the embolic agent in the posterior spinal artery via a peripheral anastomosis between the middle meningeal artery and the posterior meningeal artery was responsible for this complication. The cast of glue in the radiculopial system at the upper cervical level was visible on computed tomography scanning, and magnetic resonance imaging demonstrated circumscribed signal changes and restricted diffusion in the arterial territory of the bulbomedullary junction. The authors discuss the anatomical, clinical, and technical issues of this rare complication.

Three cases of bacterial brain abscesses, in immunocompetent patients, are reported. In all these cases, the diffusion-weighted magnetic resonance (MRI) with apparent diffusion coefficient (ADC) map has permitted an early diagnosis and a rapid treatment. This emergency MRI showed in the three cases a low signal on TI-weighted images, a high signal on T2-weighted and echo-planar images, and a decrease of ADC (0.36- 0.49 x 10(-3) mm2/s). So, this new MRI technique provides an available and rapid element in the brain abscess diagnosis which often remains a complex clinical and radiological diagnosis.

Thirty two patients with refractory central and neuropathic pain of peripheral origin were treated by chronic stimulation of the motor cortex between May 1993 and January 1997. The mean follow-up was 27. 3 months. The first 24 patients were operated according to the technique described by Tsubokawa. The last 13 cases (8 new patients and 5 reinterventions) were operated by a technique including localization by superficial CT reconstruction of the central region and neuronavigator guidance. The position of the central sulcus was confirmed by the use of intraoperative somatosensory evoked potentials. The somatotopic organisation of the motor cortex was established peroperatively by studying the motor responses at stimulation of the motor cortex through the dura. Ten of the 13 patients with central pain (77%) and nine of the 12 patients with neuropathic facial pain had experienced substantial pain relief (75%). One of the 3 patients with post-paraplegia pain was clearly improved. A satisfactory result was obtained in one patient with pain related to plexus avulsion and in one patient with pain related to intercostal herpes zoster. None of the patients developed epileptic seizures. The position of the stimulating poles effective on pain corresponded to the somatotopic representation of the motor cortex. The neuronavigator localization and guidance technique proved to be most useful identifying the appropriate portion of the motor gyrus. It also allowed the establishment of reliable correlations between electrophysiological-clinical and anatomical data which may be used to improve the clinical results and possibly to extend the indications of this technique.

Since its description by Dandy in 1922, several techniques have been used to perform third ventriculostomy under endoscopic control. Except for the blunt technique, in which the endoscope is used by itself to create the opening in the floor of the third ventricle, the other techniques require more than one instrument to perforate the floor of the ventricle and enlarge the ventriculostomy. The new device described is a sterilizable modified forceps that allows both the opening of the floor and the enlargement of the ventriculostomy in a simple and effective way. The new device has the following characteristics: 1) the tip of the forceps is thin enough to allow the easy perforation of the floor of the ventricle; 2) the inner surface of the jaws is smooth to avoid catching vessels of the basal cistern; and 3) the outer surface of the jaws has indentations that catch the edges of the opening to prevent them from slipping along the instrument's jaws. The ventricle floor is opened by gentle pressure of the forceps, which is slowly opened so that the edges of the aperture are caught by the distal outer indentation of the jaws, leading to an approximately 4-mm opening of the floor. This device has been used successfully in 10 consecutive patients. This new device allows surgeons to perform third ventriculostomy under endoscopic control in a very simple, quick, and effective way, avoiding the need for additional single-use instruments.

The endoscopic approach of the tumors of the third ventricle interests mainly the colloid cysts but also offers the possibilities of biopsies. Twenty two patients (16 men and 6 women, average age 41 years) presenting with hydrocephalus related to a tumor of the pineal area were treated by a ventriculostomy with attempt at biopsy : they are outside of the limits of this report. Twenty two other patients (15 men, 7 women, average age 39 years) were operated on from 1994 to 1999 for a colloid cyst, and 2 of them were admitted in emergency in sudden coma. The CT scan showed a colloid cyst (hyperdense in 16 patients) associated with an hydrocephalus, except for a patient previously shunted. The diameter of the cyst varied from 4 to 50 mm (average of 20 mm). All the patients were operated on using a rigid endoscope. Among the 20 patients presenting a tumor of the pineal area, a biopsy was possible only in 4 cases (20%). There were no hemorrhage nor neurological disorders. In all the cases, the size and the number of the specimens were sufficient to allow the histological diagnosis. For the patients presenting with colloid cyst, the average follow-up is 2 years. All the preoperative symptoms disappeared except for the memory disorders which were improved. The post-operative Evans index decreased significantly. No residual cyst was observed on the post-operative MRI in 14 patients (63%). Among these patients, an asymptomatic recurrence was observed and remained stable after 44 months of follow-up. A residual cyst was observed in 8 patients (36%), with a diameter from 5 to 25 mm (average 9 mm). No patient required a shunt procedure, and no patient presented hemorrhagic complication. Endoscopy is especially useful in the first line treatment of the colloid cysts of the third ventricle.

According to the development of neurosurgical endoscopy (and especially for third ventriculostomy), the endoscopic anatomy in hydrocephalus should be well known and utilized for orientation. The endoscopic pictures are obtained with a 30; telescope, acquired by a digitalized camera and visualized on a video monitor. The pictures are then numerized on a DKR system. Endoscopic anatomy of the third ventricle is described with a particular focus on the anatomical landmarks and their variations around the foramen of Monro, the anterior and posterior walls of the third ventricle. The knowledge of this anatomy is essential for the safety and the reliability of intraventricular endoscopic procedures.

Background and Purpose: We describe four cases of aneurysmal rupture during embolization with Guglielmi electrodetachable coils (GDCs) in an attempt to identify those aneurysms whose rupture during embolization represents a life-threatening risk; our emphasis is on emergency management, in particular, ventriculostomy., Methods: Medical records were reviewed retrospectively for 91 aneurysms treated with GDCs 0 to 21 days after subarachnoid hemorrhage. Rupture was ascertained by the presence of extravascular effusion of contrast medium., Results: Of the perforated aneurysms, two involved the anterior communicating artery, one the posterior inferior communicating artery, and one the basilar artery. Only two patients, whose aneurysms were located in the posterior fossa, had major complications (arterial hyperpressure, mydriasis, angiographically documented circulatory arrest or slowing). One of these patients died and the other improved after emergency ventriculostomy., Conclusion: Aneurysmal perforation during embolization may be accompanied by severe intracranial hypertension, which causes either a decrease or arrest of cerebral perfusion, the duration of which determines clinical outcome. Emergency ventriculostomy (which should be performed in the angiographic suite) is an effective means to reduce intracranial pressure. Recognition of aneurysms associated with a high risk of mortality by rupture in the course of embolization (recently ruptured small aneurysms, posterior fossa aneurysms, associated ventricular dilatation, massive cisternal hemorrhage) and use of proper logistics should ensure the effective management of this devastating complication.

Objective: Several surgical approaches have been proposed for the treatment of colloid cysts, which still remains controversial. The most recent technique used is endoscopy. By its nature, endoscopy cannot offer complete removal, as compared to microsurgical techniques, but can do more than puncture. To evaluate the usefulness of endoscopy for colloid cyst surgery, a series of 15 patients who were operated on for colloid cysts under endoscopic control since 1994 was reviewed., Methods: The presenting symptoms of our patients (10 men and 5 women) were intermittent headache (10 patients), nausea (3 patients), short-term memory loss (4 patients), coma (2 patients), gait disturbance (3 patients), blurred vision (2 patients), and mental status changes (3 patients). The sizes of the cysts ranged from 4 to 50 mm (median, 22.93 mm). Depending on the radiological appearance, the procedure was performed via a right (10 patients) or left (5 patients) precoronal burr hole. A rigid neuroendoscope was used. Initial stereotactic placement of the neuroendoscope was used in two patients who had moderate hydrocephalus. In the other patients, hand-guided endoscopy was performed using an articulated arm. The cysts were perforated with a needle. The opening was enlarged with microscissors. The cyst material was aspirated, and the remaining capsule was coagulated., Results: The average follow-up was 15.26 months (range, 1-28 mo). Total aspiration of the cysts was achieved in 12 patients, as revealed by normal postoperative magnetic resonance imaging. Control magnetic resonance imaging revealed residual cysts in three patients. One patient presented with an asymptomatic recurrence at 1 year. Resolution of the symptoms was obtained in all patients except for two of the four patients with preoperative memory deficit (improvement without complete recovery). There was no mortality or morbidity., Conclusion: These results show that endoscopy is a safe and promising percutaneous technique for the treatment of colloid cysts of the third ventricle. Longer follow-up is, however, still required.

Vascular endothelial growth factor (VEGF) appears to be implicated in tumour angiogenesis. In the present study immunohistochemical expression of VEGF was evaluated in 34 oligodendrogliomas (13 grade II, 21 grade III [WHO]). VEGF immunoreactivity was found in 31 of 34 cases. Expression of VEGF was observed in endothelial cells and some vascular smooth muscle cells, but not in neoplastic oligodendrocytes. Vessel counts, percentages of VEGF-positive vessels and vessels with vascular endothelial proliferation were assessed. The degree of VEGF labelling and vascular-endothelial proliferation in each vessel were evaluated using a 3 degree intensity score. Expression of VEGF was higher in grade III than in grade II oligodendrogliomas as assessed by percentage of VEGF positive vessels (55.8 +/- 29.2% vs 17.0 +/- 19.0% [P < 0.001]) and by VEGF immunostaining intensity (1.90 +/- 0.60 vs 0.90 +/- 0.40 [P < 0.001]). VEGF expression did not correlate with vessel density. Intensity of VEGF expression correlated positively with that of vascular-endothelial proliferation in grade III tumours (r = +0.47 [P < 0.05]). The percentage of VEGF positive vessels showed some degree of positive correlation with the percentage of vessels showing vascular-endothelial proliferation (r = +408 [P < 0.10]). Within individual grade III tumours 67.5 +/- 29.6% of all vessels with vascular-endothelial proliferation were VEGF-positive and 31.0 +/- 20.5% of all VEGF-positive vessels showed no evidence of vascular-endothelial proliferation. We conclude that (i) expression of VEGF is observed in the vasculature of oligodendrogliomas; (ii) marked expression of VEGF is observed in grade III oligodendrogliomas; (iii) VEGF may be one of the interrelated causative stimuli acting in concert to induce vascular-endothelial proliferation.

The use of an endoscope in the treatment of suprasellar arachnoid cysts provides an opening of the upper and lower cyst walls, thereby allowing the surgeon to perform a ventriculocystostomy (VC) or a ventriculocystocisternostomy (VCC). To discover which procedure is appropriate, magnetic resonance (MR)-imaged cerebrospinal fluid (CSF) flow dynamics in two patients were analyzed, one having undergone a VC and the other a VCC using a rigid endoscope. Magnetic resonance imaging studies were performed before and after treatment, with long-term follow-up periods (18 months and 2 years). The two patients were reoperated on during the follow-up period because of slight headache recurrence in one case and MR-imaged CSF flow dynamics modifications in the other. In each case surgery confirmed the CSF flow dynamics modifications appearing on MR imaging. In both cases, long-term MR imaging follow-up studies showed a secondary closing of the upper wall orifice. After VCC, however, the lower communication between the cyst and the cisterns remained functional. The secondary closure of the upper orifice may be explained as follows: when opened, the upper wall becomes unnecessary and tends to return to a normal shape, leading to a secondary closure. The patent sylvian aqueduct aids the phenomenon, as observed after ventriculostomy when the aqueduct is secondarily functional. The simplicity of the VCC performed using endoscopic control, which is the only procedure to allow the opening in the cyst's lower wall to remain patent, leads the authors to advocate this technique in the treatment of suprasellar arachnoid cysts.

The authors present an observation of intraorbital hydatid cyst. They review the literature and discuss the main data of such a rare lesion. Hydatid cyst should be systematically evoked in any case of tumoral exophthalmia developed in a young patient, particularly if he comes from an endemic country. The pre-operative diagnosis relies on the confrontation between clinical and echographical data, and C.T.-scan imaging. The only treatment is surgery. A puncture performed at the beginning of the surgical procedure will confirm the diagnosis. In fact, it should be indicated for every intra-orbital neoplasm observed in a country of endemicity, mostly when the preoperative diagnosis is difficult, that is when no C.T.-scan or echography are at disposal. The infectious prognosis is excellent; but the functional one depends on the precocity of surgery and remains reserved in most cases.