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Dorsal rhizotomy is a controversial procedure for treating spasticity in children with cerebral palsy, particularly regarding the influence of intraoperative neuromonitoring (ION). The objective of this study was to evaluate the influence of ION in adjusting root sectioning compared the preoperative program established by the multidisciplinary team.Twenty-four consecutive children with spastic diplegia or quadriplegia, operated on between 2017 and 2020 in the University Hospital of Nancy, France, were studied. All underwent the same procedure: Keyhole Intralaminar Dorsal rhizotomy (KIDr) with enlarged multilevel interlaminar openings to access all roots from L2 to S2. The Ventral Root (VR) was stimulated to map radicular myotomes, and the Dorsal Root (DR) to test excitability of the segmental circuitry. Muscle responses were observed independently by the physiotherapist and by EMG-recordings. The study compared final root sectioning per radicular level and per side after ION versus the preoperative program determined by the multidisciplinary team.ION resulted in significant differences in final percentage root sectioning (P0.05), with a decrease for L2 and L3 and an increase for L5. ION modified the symmetry of sectioning, with 32% instead of 5% in preoperative program. Only 5 children showed change in GMFC score 6 months after surgery.The use of ION during dorsal rhizotomy led to important modifications of root sectioning during surgery, which justifies individual control of each root, level by level and side by side, to optimize the therapeutic effect.

Introduction/But Presentation des resultats d’une serie homogene et prospective d’enfants atteints de diplegie spastique traites par une technique de radicotomie dorsale permettant de cibler chacune des racines lombo-sacrees et de respecter l’architecture rachidienne posterieure. Materiel et methodes Les patients ont ete selectionnes par une meme equipe multidisciplinaire, avec etablissement d’un planning chirurgical propre a chaque enfant. Les 22 enfants inclus ont beneficie d’une radicotomie dorsale selon les memes modalites techniques. Ces abords interlamaires elargis respectent partiellement les lames et les epineuses ainsi que la totalite du ligament interepineux. Ces abords interlamaires sont a 3 niveaux : L1-L2 pour acces aux racines L2 et L3, L3-L4 pour les racines L4 et L5 et L5-S1 pour les racines S1 et S2. Les racines sont visualisees et identifiees en intradural lors de leur sortie au foramen a chaque niveau. Chaque racine ventrale est stimulee pour en verifier le territoire d’innervation motrice et chaque racine dorsale est stimulee pour evaluer son degre d’excitabilite. Les reponses motrices de chaque groupe musculaire des membres inferieurs (et le sphincter anal) sont observees cliniquement par le kinesitherapeute et enregistrees par EMG. Les sections radiculaires posterieures sont realisees selon la charte preoperatoire mais avec ajustements issus du monitorage peroperatoire. Resultats Les objectifs vises en preoperatoire ont ete atteints chez 21 des 22 patients. Le degre d’amelioration a ete evalue par le GMFM Score. Le programme reeducatif a pu etre debute des le 10eme jour post-operatoire. Il n’a pas ete constate d’aggravation neurologique hormis chez un patient (deficit quadricipital gauche), de perte de la fonction urinaire, d’hypoesthesie, paresthesies ou douleurs sequellaires. Conclusion Ces resultats montrent que la technique utilisee a permis une amelioration fonctionnelle chez les enfants diplegiques marchants et une amelioration des possibilites de soins et de la qualite de vie chez les enfants quadriplegiques. Aucune destabilisation du rachis n’est survenue.

International audience; Over the last decades microvascular decompression (MVD) has been established as the curative treatment of the primary Hemifacial Spasm (HFS), proven to be linked in almost all cases to a neurovascular compression of the facial nerve. Because the disease is not life-threatening and MVD not totally innocuous, efficacy and safety have to be weighted before decision taken of indicating surgery. The authors have been charged by the French Speaking Society of Neurosurgery to conduct a detailed evaluation of the probability of relief of the spasm that MVD is able to obtain, together with its potential complications. For the review, the authors have gone through the reports available from the Pubmed system. Eighty-two publications have been read and analysed, totalizing more than 10,000 operated cases. In most series, the percentage of patients with total relief ranged between 85% and 90%. Relief was obtained after a certain delay in as many as in 33%±8% of the patients in many series. For those, delay lasted around one year in 12% of them. When effect of MVD was considered achieved, relief remained permanent in all but 1%-2% of the long-term followed patients. As regards to complications, risk of permanent cranial nerve deficit was evaluated at 1%-2% for facial palsy, 2%-3% for non-functional hearing loss, 0.5%-1% for lower cranial nerve dysfunction. Risk of stroke was at 0.1% and mortality at 0.1%. CSF leakage and related complications could be reduced at less than 2% in most series provided careful closing techniques be applied. Complications were at a higher rate in repeated MVD. MVD is an effective curative method for almost all the patients affected with primary HFS. Because MVD for HFS is functional surgery, scrupulous consideration of its potential risks, together with the ways to avoid complications are of paramount importance. When MVD is estimated to have failed, it is wise to wait one year before considering to repeat surgery, as number of patients may benefit from delayed effect. This is the more so as important as repeated surgery entails a higher rate of complications.

Trigeminal neuralgia is, in a large majority of cases (96%), due to a neurovascular compression at the level of the trigeminal root. Chronic pulsatile compression creates focal demyelination, with short-circuits between fibers and generation of ectopic influxes responsible for intense paroxysmal pain. Microvascular decompression (MVD), in those cases in whom high-resolution MRI shows evidence of a neurovascular compression, obtains long-term relief in a significant number of patients, 62% to 89% of the cases according to series. MVD, because it is a curative and conservative treatment of TN, is the first surgical option. Lesioning techniques with percutaneous approaches or stereotactic radiosurgical methods are alternatives for patient with precarious general conditions or in whom MRI cannot demonstrate neurovascular compression.

International audience; Primary hemifacial spasm with few exceptions is due to the vascular compression of the facial nerve that can be evidenced with high resolution MRI. Microvascular decompression is the only curative treatment for this pathology. According to literature review detailed in chapter "conflicting vessels", the compression is located at the facial Root Exit Zone (REZ) in 95% of the cases, and in 5% distally at the cisternal or the intrameatal portion of the root as the sole conflict or in addition to one at brainstem/REZ. Therefore, exploration has to be performed on the entire root, from the ponto-medullary fissure to the internal auditory meatus. Because microvascular decompression is functional surgery, the procedure should be as harmless as possible and with a high probability of permanent efficacy. Besides facial palsy, main complications are hearing loss, tinnitus and gait disturbances. Causes are cochlea/labyrinth ischemia due to manipulations of their nutrient arteries and/or stretching of the eight nerve complex. To minimize the latter, the approach should not be with lateral-to-medial retraction of the cerebellar hemisphere, but along an infra-floccular trajectory, from below. In fact, most of the neurovascular conflicts are situated ventro-caudally to facial REZ at the brainstem, particularly those from a megadolicho-vertebrobasilar artery and its posterior inferior-cerebellar branch. Also, care should be taken not to cause any injury of the manipulated vessels or stretching of their perforators to brainstem. Heating from bipolar coagulation must be avoided. The inserted material used to maintain the offending vessel(s) away must not be neo-compressive. Intraoperative neuromonitoring is considered to be useful for achieving safe surgery at least until the learning curve has reached an optimal level, particularly BrainstemAuditory Evoked Potentials recordings. Increase in latency and/or decrease in amplitude of wave V warn excessive stretching or damage to the cochlear nerve, and decrease in amplitude of wave I signals possible ischemia of the cochlea. Free-running EMG of the facial muscles may warn against excessive manipulation of the facial nerve. Recording of the lateral spread responses - which are a sign of hyperexcitabilty of the facial motor system - may provide information on completeness of the decompression.

International audience; Primary hemifacial spasm is a hyperactive cranial nerve syndrome. The cause is always a neurovascular compression, generally at the root exit zone from the brainstem. Its curative treatment is microvascular decompression, that may be performed as a first option, or secondarily when botulinum toxin injections fail.

Introduction La Radicotomie Dorsale, intervention ancienne indiquee essentiellement chez l’enfant diplegique spastique, peut-etre realisee selon des abords interlamaires segmentaires de type KIDr (Keyhole Interlaminar Dorsal rhizotomy)permettant un monitoring EMG per-operatoire precis. Nous rapportons les resultats des 7 premiers cas de la serie nanceienne realises selon ses modalites. Materiel et methodes Chez chaque enfant, une charte pre-operatoire a ete etablie de facon multidisciplinaire avec les objectifs attendus et la quantification de la section de chacune des racines selectionnees. Les 7 interventions on ete realisees selon les memes modalites avec abords interlamaires type KIDr et monitoring EMG per-operatoire par stimulation des racines ventrale et dorsale de toutes les racines lombo-sacrees de L2 a S2 de chaque cote realise avec le stimulateur Icare d’Innopsys. Un controle par observationclinique des reponses motrices etait egalement realise en parallele par un kinesitherapeute. La duree d’hospitalisation fut de 9 jours en moyenne. Tous les patients ont ensuite ete transfere en centre de reeducation specialisee pour une duree de 6 semaines. Resultats La duree moyenne de l’intervention etait de 5h30. Aucune complication per- ou post-operatoire hormis un pseudo meningocele n’a ete observe. La spasticite a diminue chez tout les enfants a 1 mois (Ashworth de 3,3 a 1,7). Trois patients sur 7 ont eu une aggravation fonctionnelle pour le 1er mois (marche), en relation avec l’hypotonie, cette derniere a toujours recupere a 6 mois laissant une spasticite amelioree. 5 patients ont decrits des le 1er mois une diminution des douleurs des membres inferieurs presentes avant l’intervention. Six familles sur 7 se declaraient satisfaites. Conclusion La radicotomie dorsale realisee avec l’abord de type KIDr et monitoring EMG per-operatoire donne des resultats satisfaisants chez l’enfant en permettant une diminution de la spasticite et une amelioration fonctionnelle.

In nearly all cases, primary hemifacial spasm is related to arterial compression of the facial nerve in the root exit zone at the brainstem. The offending arterial loops originate from the posterior inferior cerebellar, anterior inferior cerebellar, or vertebrobasilar artery. In as many as 40% of the patients, neurovascular conflicts are multiple. The cross-compression at the brainstem is almost always seen on magnetic resonance imaging combined with magnetic resonance angiography. Botulinum toxin can be useful by alleviating the symptoms, but the effects are inconstant and only transient. The definitive conservative treatment is microvascular decompression (MVD), which cures the disease in 85 to 95% of patients. In expert hands, the MVD procedure can be done with relatively low morbidity. Because cure of spasms is frequently delayed – by several months to even a few years –, we do not recommend early reoperation in patients with failure or until at least 1 year of follow-up. Delayed cure could well be explained by the slow reversal of the plastic changes in the facial nucleus that may have caused the symptoms.

Percutaneous radiofrequency (RF) thermorhizotomy of the trigeminal nerve is an effective treatment for trigeminal neuralgia. Long-term efficacy is proportional to the degree of postoperative hypoesthesia. The advantage is the topographic selectivity of the thermolesion, provided the electrode tip is placed accurately. This requires precise x-ray guidance and neurophysiological testing. In addition to the indication in idiopathic trigeminal neuralgia, especially for elderly patients with precarious conditions, thermorhizotomy is particularly useful for treating patients with trigeminal neuralgia due to multiple sclerosis. It can also be applied to symptomatic neuralgias, but only when the main components are of the paroxysmal and/or the allodynic types ; the thermorhizotomy method could aggravate permanent components, especially when burning pain predominates; it could also increase preexisting trophic disturbances, particularly keratitis.

Glossopharyngeal neuralgia, more accurately called vago-glossopharyngeal neuralgia (VGPN) because of the frequent association with pain irradiation in the sensory territory of the vagus nerve, is not always recognized because its incidence is much lower than the incidence of trigeminal neuralgia (100 times more frequent). As in trigeminal neuralgia, when pain becomes resistant to anticonvulsants – its specific medical treatment – VGPN can almost always be cured by surgery. The first option is microvascular decompression, since vascular compression is the main cause of the neuralgia. Percutaneous thermorhizotomy at the foramen jugularis (pars nervosa) is only indicated as a second option, because of unavoidable sensorimotor deficits in the ninth and tenth nerves. Tractonucleotomies at the medullary level should be reserved essentially for pain of malignant origin.

Vagoglossopharyngeal neuralgia is a rare pathology whose atypical forms, dominated by syncopal manifestations, are still rarer. Although the territory of the vagus nerve involves, beyond the cardiovascular system, the respiratory and the digestive systems, there is no report in literature of atypical forms other than syncopal. Therefore, the authors were prompted to report the case of a patient whose vagoglossopharyngeal neuralgia was predominantly revealed by digestive symptoms. A 58-year-old patient presented with stereotypical severe digestive disturbances including nausea, vomiting and diarrhoea. High definition cranial MRI showed a neurovascular conflict between the posterior inferior cerebellar artery and the IXth and Xth nerves, on the right side. A microsurgical decompression was carried out which confirmed the vascular compression and successful transposition of the artery. One year after the surgery, the patient was free from all painful and digestive symptoms. A survey of the literature did not find any reference to digestive symptoms together with the neuralgia; only a syncopal type of cardiac symptoms related to the parasympathetic nervous system were described. The hypothesis was that the revealing digestive symptoms are linked to a similar parasympathetic mechanism, implying the visceral component of the Xth cranial nerve.

Resume La neurochirurgie moderne permet de controler dans presque tous les cas la nevralgie trigeminale essentielle pharmacoresistante. L’on peut avoir recours a deux grands types de methodes. Les premieres correspondent a l’interruption des voies nociceptives. Elles sont, soit percutanees : il en est ainsi de la thermocoagulation retrogasserienne, de la compression par ballonnet gonflable et de la neurolyse par injection de glycerol dans le cavum de Meckel, soit par radiochirurgie au moyen du gamma-knife qui est tres precis. Le second type de methodes est la decompression vasculaire microchirurgicale qui leve le conflit vasculonerveux de la racine trigeminale. Cette methode qui est conservatrice et curative necessite un abord direct et une anesthesie generale ; elle s’adresse aux patients de moins de 70 - 75 ans, en bon etat general. Lorsque les patients sont tres âges et/ou en etat general precaire, les methodes percutanees ou la radiochirurgie sont preferables, mais la duree de leur efficacite est proportionnelle au degre d’hypoesthesie sequellaire, avec ses consequences.

Purpose To assess whether conformal radiotherapy (CRT) after incomplete surgery or biopsy for pure oligodendrogliomas and mixed gliomas results in decreased long-term sequelae without impairing local control and while reducing irradiated volume. Materials and methods Twenty-six consecutive patients who presented with pure (21) or mixed (5) oligodendrogliomas and who were given incomplete resections were treated according 3 different strategies: CRT alone (12), chemotherapy followed by CRT (4), and chemotherapy and delayed CRT at the time of tumor progression (10). CRT consisted of multiple noncoplanar fields. Median dose was 60 Gy. Quality of CRT was assessed using tumor and normal tissue conformal indexes. The location of recurrences was assessed with MRI and dosimetric data. Late sequelae were assessed by a questionnaire exploring professional outcome, and also by a Mini Mental State Examination test. Results The mean overall survival was 5.2 years. Fifteen patients experienced a local relapse. All but 1 occurred in the 95% isodose. Among 11 nonevolutive patients, 6 have a full-time or part-time job. Conclusion Despite CRT, infield recurrence was a common feature in patients with oligodendrogliomas and mixed tumors. Further research, including molecular biology typing of tumors and type of treatment, is warranted to improve survival and quality of life.

Introduction La valeur diagnostique de l’IRM pour etablir la responsabilite d’un conflit neurovasculaire (CNV) dans une nevralgie trigeminale (NT) reste contestee en particulier du fait que des relations vasculaires avec le trijumeau existent chez nombre d’individus n’ayant pas de NT ou du cote asymptomatique d’un porteur de nevralgie. Patients et methode L’etude a porte sur 100 IRM faites en preoperatoire, IRM a haute resolution, associant : un T2-DRIVE, un TOF-Angio et un T1-Gado. Les images ont ete evaluees par un examinateur (chirurgien senior) masque des donnees operatoires et cliniques, y compris le cote de la nevralgie. L’examinateur a decrit toutes les relations neurovasculaires avec le trijumeau, et cela des deux cotes, puis en fonction de celles-ci, en particulier de leur degre de compression a estime quel devrait etre le cote de la nevralgie. Dans un second temps apres demasquage, les estimations de l’examinateur ont ete confrontees aux donnees cliniques, en particulier le cote de la NT, ainsi qu’aux donnees anatomiques operatoires. Resultats L’erreur de prediction du cote globale a ete de 25/100. Elle a ete de 58,3 % lorsque les images de relation neurovasculaire etaient relativement symetriques (18/31) et de 10,1 % lorsqu’elles etaient relativement asymetriques (7/69) (p = 0,003). Dans les 69 cas qualifies « d’asymetriques », il n’y avait aucune image de CVN y compris de simple contact du cote asymptomatique chez 60 patients. Chez les 9 autres patients, le degre de compression du cote asymptomatique etait nettement plus faible. Dans les 31 cas qualifies de « relativement symetriques », le degre de compression etait un peu plus eleve du cote de la nevralgie (+0,35 degres), mais de facon non-significative. Par ailleurs, le vaisseau conflictuel a ete correctement identifie dans 89 % des cas, tous patients confondus, avec une concordance de degre dans 60 % des cas. Conclusion Dans la majorite des patients avec une NT, un CVN unilateral est identifie avec le cote de la nevralgie evident seul sur l’imagerie. Dans un tiers des patients, une configuration symetrique des deux cotes ne permet pas l’identification sans correlation clinique du cote nevralgique, ces patients presentant des conflits bilateraux symetriques. L’IRM correctement effectuee reste fiable pour identifier les CVN dans les deux types de configuration.

Lateral spread responses (LSR), an electrophysiological characteristic of hemifacial spasm (HFS), can be recorded during surgery. This work aims at evaluating the prognostic value of the persistence or suppression of the LSR at the end of the microvascular decompression (MVD) procedure of the facial nerve. Thirty-three patients with HFS, which had been evolving for 5.5 years, underwent MVD with intraoperative EMG. Monitoring required the placement of a needle in the frontalis and mentalis muscles. Responses were recorded after stimulation of inferior or superior branches of the facial nerve to search for abnormal ephaptic LSR. Preoperative abnormal LSRs were present in all patients. In 23 patients, LSR disappeared with vascular decompression and was not present upon closure. Among those patients, 20 were considered clinically cured and three still presented with mild/moderate spasm at 3-month follow-up. At late follow-up, 22 patients were free of spasm. One patient had recurrence of spasm at month 10. On the contrary, 10 patients had persistent abnormal LSR upon closure. Among those, seven were cured at early follow-up (3 months on average), whereas spasm disappeared at late follow-up (12 to 36 months) in the other three patients. The prognostic value of LSR monitoring is questionable; a good clinical result may be obtained in patients who presented with persistent LSR at the end of MVD. Delayed cure strongly supports the hypothesis that HFS is not only due to the mechanical pulsations of the elongated artery against the root exit zone of the facial nerve, but also to demyelination of the nerve and/or hyperactivity of the facial motornucleus generated by the neurovascular compression.

Surgery should be considered only after anticonvulsant medications have failed or if medical treatment is not well-tolerated, including in cases of asthenia or drowsiness. In most reference centers, consensus is that MVD is the first option when patients are in good health. Percutaneous lesioning operations or radiosurgery are preferable in patients with adverse co-morbidity or those who are not willing to undergo open surgery.

MVD of the left rostral ventrolateral medulla oblongata may be an effective treatment for patients suffering from intractable severe systemic blood hypertension. This article presents a literature review. Further clinical controlled studies have to be conducted to define precise indications.

Replication-defective Moloney murine leukemia virus expressing the GAD67 gene under the control of the GFAP promoter was produced using selected clones of a fibroblast-packaging cell line. A spontaneously immortalized astrocyte cell line was infected with this virus and cellular clones expressing GAD67 selected. Astrocyte and fibroblast clones expressed functional GAD (detected by glutamic acid decarboxylation), but only fibroblasts were able to also produce GABA in the extracellular medium. When exposed to 200 microM glutamate, despite an observed difference in the rates of glutamate accumulation in control and GAD67-expressing astrocytes, similar proportions of glutamate taken up were detected. In GAD67-expressing astrocytes, the glutamate was mainly converted into GABA, suggesting GAD transgene activity to be dominant over other glutamate metabolic pathways, such as glutamine synthetase and glutamate dehydrogenase. Moreover, rapid GABA release into the cell medium was also observed, suggesting the involvement of reverse GABA transporters. The use of the GFAP promoter might be able to take advantage of its activation in response to factors inducing reactive gliosis observed in pathological insults. GAD67-expressing astrocytes might therefore be used for future grafting in pathological situations in which an excess of glutamate results in neuronal dysfunction or cell death.

This series reports a pilot study of chemotherapy conducted for newly diagnosed and relapsing patients with oligodendrogliomas and oligoastrocytomas. Twenty-three patients with clinically or histologically aggressive tumours were eligible to receive procarbazine CCNU and vincristine (PCV) chemotherapy followed by radiotherapy in previously non irradiated patients. Sixteen (69%) responded to chemotherapy with complete responses in two patients and partial responses in 14. Previously irradiated patients were as likely to respond to PCV as those previously non irradiated. An over 1-year history of seizures was the main clinical prognostic factor of response. All toxicities were manageable and no treatment related deaths occurred. Chemotherapy is an effective treatment in aggressive oligodendrogliomas. Further studies must assess the role of chemotherapy in the multidisciplinary management of oligodendroglioma.

A series including 13 unilateral selective tibial neurotomies for spastic foot in hemiplegic children is reported. The results were considered excellent in three cases. Two cases needed additional corrective casts postoperatively. Eight cases had poor result with recurrence of the same deformity. The authors conclude that the effect of tibial neurotomy for spastic foot in hemiplegic children is transient in 61% of cases with a recurrence of the same deformity. Four of the patients with failed treatment underwent orthopedic surgery with muscle biopsies. Histologic data clearly demonstrate that previously denervated muscle fibers were reinnervated carrying into extensive motor units. This finding can explain the recurrence of the foot spasticity and deformity in neurotomized children.

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.

Resume Le but de notre travail etait d'objectiver les effets de la radicotomie posterieure fonctionnelle chez l'enfant infirme moteur cerebral (IMC) quadriplegique dans les domaines orthopedique et fonctionnel. Nous avons etudie 18 enfants IMC de 5 a 16 ans, en preoperatoire et a 1 an postoperatoire, en ce qui concerne la spasticite, l'etat orthopedique et la fonction. Nous avons mis en evidence une diminution franche de la spasticite. Cette diminution ne permet pas de prevention orthopedique. En revanche, on observe une amelioration fonctionnelle qualitative que les echelles actuelles sont insuffisantes a mesurer.

Knowledge of the pathological diagnosis before deciding the best strategy for treating parasellar lesions is of prime importance, due to the relative high morbidity and side-effects of open direct approaches to this region, known to be rich in important vasculo-nervous structures. When imaging is not evocative enough to ascertain an accurate pathological diagnosis, a percutaneous biopsy through the transjugal-transoval route (of Hartel) may be performed to guide the therapeutic decision.The chapter is based on the authors' experience in 50 patients who underwent the procedure over the ten past years. There was no mortality and only little (mostly transient) morbidity. Pathological diagnosis accuracy of the method revealed good, with a sensitivity of 0.83 and a specificity of 1.In the chapter the authors first recall the surgical anatomy background from personal laboratory dissections. They then describe the technical procedure, as well as the tissue harvesting method. Finally they define indications together with the decision-making process.Due to the constraint trajectory of the biopsy needle inserted through the Foramen Ovale, accessible lesions are only those located in the Meckel trigeminal Cave, the posterior sector of the cavernous sinus compartment, and the upper part of the petroclival region.The authors advise to perform this percutaneous biopsy method when imaging does not provide sufficient evidence of the pathological nature of the lesion, for therapeutic decision. Goal is to avoid unnecessary open surgery or radiosurgery, also inappropriate chemo-/radio-therapy.

Previous literature includes numerous reports of acute stereotactic ablation for epilepsy. Most reports focus on amygdalotomies or amygdalohippocampotomies, some others focus on various extra-limbic targets. These stereotactic techniques proved to have a less favourable outcome than that of standard surgery, so that their rather disappointing benefit/risk ratio explains why they have been largely abandoned. However, depth electrode recordings may be required in some cases of epilepsy surgery to delineate the best region of cortical resection. We usually implant depth electrodes according to Talairach's stereo electroencephalography (SEEG) methodology. Using these chronically implanted depth electrodes, we are able to perform radiofrequency (RF)-thermolesions of the epileptic foci. This paper reports the technical data required to perform such multiple cortical thermolesions, as well as the results in terms of seizure outcome in a group of 41 patients. TECHNICAL DATA: Lesions are placed in the cortex areas showing either a low amplitude fast pattern or spike-wave discharges at the onset of the seizures. Interictal paroxysmal activities are not considered for planning thermocoagulation sites. All targets are first functionally evaluated using electrical stimulation. Only those showing no clinical response to stimulation are selected for thermolesion, including sites located inside or near primary functional area. Lesions are performed using 120mA bipolar current (50 V), applied for 10-30 sec. Each thermocoagulation produces a 5-7mm diameter cortical lesion. A total of 2-31 lesions were performed in each of the 41 patients. Lesions are placed without anaesthesia.20 patients (48.7%) experienced a seizure frequency decrease of at least 50% that was more than 80% in eight of them. One patient was seizure free after RF thermocoagulation. In 21 patients, no significant reduction of the seizure frequency was observed. Amongst the characteristics of the disease (age and sex of the patient, lobar localization of the EZ) and the characteristics of the thermocoagulations (topography, lateralization, number, morphology of the lesions on MRI) no factor was significantly linked to the outcome. However, the best results were clearly observed in epilepsies symptomatic of a cortical development malformation (CDM), with 67% of responders in this group of 20 patients (p = 0.052). Three transient post-procedure side-effects, consisting of paraesthetic sensations in the mouth (2 cases), and mild apraxia of the hand, were observed.SEEG-guided-RF-thermolesioning is a safe technique. Our results indicate that such lesions can lead to a significant reduction of seizure frequency. Our experience suggests that SEEG-guided RF thermocoagulation should be dedicated to drug-resistant epileptic patients for whom conventional resection surgery is risky or contra-indicated on the basis of invasive pre-surgical evaluation, particularly those suffering from epilepsy symptomatic of cortical development malformation.

Neuropathic pain (NP) may become refractory to conservative medical management, necessitating neurosurgical procedures in carefully selected cases. In this context, the functional neurosurgeon must have suitable knowledge of the disease he or she intends to treat, especially its pathophysiology. This latter factor has been studied thanks to advances in the functional exploration of NP, which will be detailed in this review. The study of the flexion reflex is a useful tool for clinical and pharmacological pain assessment and for exploring the mechanisms of pain at multiple levels. The main use of evoked potentials is to confirm clinical, or detect subclinical, dysfunction in peripheral and central somato-sensory pain pathways. LEP and SEP techniques are especially useful when used in combination, allowing the exploration of both pain and somato-sensory pathways. PET scans and fMRI documented rCBF increases to noxious stimuli. In patients with chronic NP, a decreased resting rCBF is observed in the contralateral thalamus, which may be reversed using analgesic procedures. Abnormal pain evoked by innocuous stimuli (allodynia) has been associated with amplification of the thalamic, insular and SII responses, concomitant to a paradoxical CBF decrease in ACC. Multiple PET studies showed that endogenous opioid secretion is very likely to occur as a reaction to pain. In addition, brain opioid receptors (OR) remain relatively untouched in peripheral NP, while a loss of ORs is most likely to occur in central NP, within the medial nociceptive pathways. PET receptor studies have also proved that antalgic Motor Cortex Stimulation (MCS), indicated in severe refractory NP, induces endogenous opioid secretion in key areas of the endogenous opioid system, which may explain one of the mechanisms of action of this procedure, since the secretion is proportional to the analgesic effect.

The authors report a series of 30 adults with medulloblastoma treated after surgery between 1975 and 1990, Half the patients presented a classical medulloblastoma and the other half presented desmoplastic medulloblastoma. Brainstem infiltration was noted in 3 patients, cerebellar peduncle infiltration in 6 cases and 4 patients had cerebrospinal fluid (CSF) involvement. Tumor resection was achieved in all patients except 1, and in 5 surgery was incomplete. All patients but 2 received postoperative cerebral radiotherapy. Six patients did not receive chemotherapy before radiotherapy, 7 patients received CCNU-Vincristine concomitantly with and after irradiation, 1 patient was given a CHOP regimen, and the remaining 16 patients received the 8 drugs in a 1-day (8/1) regimen before irradiation. The median follow-up time was 104 months. The 5- and 10-year overall survival rates were 58.5% and 41%, respectively. Two toxic deaths occurred under the 8/1 regimen, and no better survival was observed for this group of patients in comparison with those receiving other regimens. Persistance of malignant cells in the CSF, brainstem involvement, cerebellar peduncle infiltration, non-radical surgery and a postoperative performance status (PS) of more than 2 were significantly correlated with an adverse outcome for overall survival in adult patients with medulloblastoma.

Case 1, a 61-year-old female presented with paresthesia of her right upper lip. Computed tomography (CT) and magnetic resonance (MR) imaging with contrast material revealed an enhanced mass in the right Meckel's cave, which included the lateral and posterior parts of the cavernous sinus and surrounded the right internal carotid artery. To establish the best surgical strategy, a percutaneous biopsy through the foramen ovale was performed, and the histological examination indicated that the tumor was a transitional meningioma. We performed combined treatment with microsurgery and radiosurgery. Case 2,a 66-year-old female presented with paresthesia of the right side of her face. MR images with gadolinium revealed an abnormal enhanced mass at the right Meckel's cave, and a CT scan with a bone window showed a large foramen ovale in the right side. We performed a percutaneous biopsy using the same method, but this tumor was too hard to sample through the needle. Although this manipulation has the major advantage of establishing the best therapeutic strategy and avoiding unnecessary surgery, special care should be taken for hard tumors, especially for those aspirated by needle biopsy.

Posterior craniocervical decompression is the procedure most currently used for treating Chiari I malformation (alone or in association with syringomyelia in the absence of hydrocephalus). We reviewed the various technical modalities reported in the literature. We present a personal series of 44 patients harboring Chiari type I malformation (CM-I) operated with a suboccipital craniectomy and a C1 (or C1/C2) laminectomy, plus an extreme lateral Foramen Magnum opening, a "Y" shaped dural incision with preservation of the arachnoid membrane, and an expansile duraplasty employing autogenous periosteum. Outcomes were analyzed with follow-up ranging from 1 to 10 years (4 years on average). The presented technique was compared with the other surgical modalities reported in the literature. This comparative study shows that this type of craniocervical decompression achieved the best results with minimal complications and side-effects. Syringomyelia associated with CM-I must be treated by craniocervical decompression alone. Shunting no longer appears to be an appropriate method of treatment for syringomyelia.

Technical modalities for the evacuation of chronic subdural hematomas are still controversial. The Twist-Drill technique with closed-system drainage is becoming more widely used, but the influence of drainage duration on outcome has not been studied yet and therefore is still being debated.A prospective randomized study was conducted, comparing the results between two drainage durations. Forty-eight hours (Group I; n=35 patients) and 96 h (Group II; n=30 patients).The two groups had almost identical characteristics due to randomization. The mean volume of liquid drained was 120 ml in the first group and 285 ml in the second, a statistically significant difference. The rate of incomplete evacuation versus the rate of recurrence did not show any significant difference between Group I (5.7 % and 11.4 %, respectively) and Group II (3.3 % and 10 %, respectively). The rate of postoperative complications was 10.7 % in Group I but 26.9 % in Group II, with a respective 3.8 % and 11.4 % mortality rate, proving a statistically significant difference. Clinical improvement observed at discharge was 85.7 % and 84.6 % in Group I and Group II, respectively.With comparable recurrence and improvement rates, our study demonstrates that it is much more advantageous to remove the catheter at 48 h than leave it in for a longer duration. Not only is bed rest reduced, but the rate of morbidities is also significantly decreased.

We report the results of an investigation carried out on the activity of functional neurosurgery of the cranial nerves in the French-speaking countries, based on the analysis of a questionnaire addressed to all the members of the SNCLF Eighteen centers responded to this questionnaire., which showed that activities and indications varied greatly from one unit to another. The results appear homogeneous and comparable with those reported in the literature. The questionnaire sought to provide a global perspective, open to the comments and questions of all responders on the various techniques raised, with the objective of establishing a common decisional tree for these pathologies and providing if possible to a consensus for better dissemination of these therapies. (C) 2009 Elsevier Masson SAS. All rights reserved.

The percutaneous Hartel transoval route goes through an inverted pyramid, with an inferior summit and a superior base that includes three compartments. The danger of the inferior compartment is the parotid duct. The middle compartment contains many branches of the mandibular nerve. The superior compartment is crossed by the internal maxillary artery and its branches, as well as the auditory tube. The base of the pyramid presents not only the foramen ovale, but also the foramen lacerum, where the trocar may injure the internal carotid, and the foramen jugulare, where the trocar may meet the internal jugular vein and nerves of the pars nervosa (IX, X, XI). The trigeminal cave contains, within the trigeminal cistern, the trigeminal ganglion, extended backward by the triangular plexus (the target for thermocoagulation). These structures are undercrossed by the masticatory motor branch of the trigeminal nerve.

In nearly all cases, primary hemifacial spasm is related to arterial compression of the facial nerve in the root exit zone at the brainstem. The offending arterial loops originate from the posterior inferior cerebellar, anterior inferior cerebellar, or vertebrobasilar artery. In as many as 40% of the patients, neurovascular conflicts are multiple. The cross-compression at the brainstem is almost always seen on magnetic resonance imaging combined with magnetic resonance angiography. Botulinum toxin can be useful by alleviating the symptoms, but the effects are inconstant and only transient. The definitive conservative treatment is microvascular decompression (MVD), which cures the disease in 85 to 95% of patients. In expert hands, the MVD procedure can be done with relatively low morbidity. Because cure of spasms is frequently delayed - by several months to even a few years -, we do not recommend early reoperation in patients with failure or until at least 1 year of follow-up. Delayed cure could well be explained by the slow reversal of the plastic changes in the facial nucleus that may have caused the symptoms.