[Vagus nerve stimulation for the treatment of refractory epilepsy]. / Stimulation chronique du nerf vague dans le traitement del'épilepsie pharmacorésistante.

Proposed as an additive symptomatic treatment of refractory epilepsy, vagus nerve stimulation (VNS) has proven to be effective and well-tolerated in patients presenting with refractory epilepsy for whom cortical resection is not indicated. After two years of treatment, the overall reduction of seizure frequency averaged 40%. In 50% of the patients, the frequency of seizures decreased by at least 50%. Moreover, even in absence of a significant reduction of seizures, patients who undergo this treatment reported an improvement in their quality of life. Economic surveys also demonstrate a favorable impact of VNS on the management of refractory epilepsy. Since 1988, 65,000 patients with refractory epilepsy throughout the world have been treated by VNS for this indication (1000 in France). The surgical implantation technique used in our department, the effects of vagus nerve stimulation reported in the literature, and our experience with a cohort of 70 patients with refractory epilepsy who received implants over the last 10 years are described.

Cortical areas involved in Arabic number reading.

OBJECTIVE: Distinct functional pathways for processing words and numbers have been hypothesized from the observation of dissociated impairments of these categories in brain-damaged patients. We aimed to identify the cortical areas involved in Arabic number reading process in patients operated on for various brain lesions. METHODS: Direct cortical electrostimulation was prospectively used in 60 brain mappings. We used object naming and two reading tasks: alphabetic script (sentences and number words) and Arabic number reading. Cortical areas involved in Arabic number reading were identified according to location, type of interference, and distinctness from areas associated with other language tasks. RESULTS: Arabic number reading was sustained by small cortical areas, often extremely well localized (<1 cm(2)). Over 259 language sites detected, 43 (17%) were exclusively involved in Arabic number reading (no sentence or word number reading interference detected in these sites). Specific Arabic number reading interferences were mainly found in three regions: the Broca area (Brodmann area 45), the anterior part of the dominant supramarginal gyrus (Brodmann area 40; p < 0.0001), and the temporal-basal area (Brodmann area 37; p < 0.05). Diverse types of interferences were observed (reading arrest, phonemic or semantic paraphasia). Error patterns were fairly similar across temporal, parietal, and frontal stimulation sites, except for phonemic paraphasias, which were found only in supramarginal gyrus. CONCLUSION: Our findings strongly support the fact that the acquisition through education of specific symbolic entities, such as Arabic numbers, could result in the segregation and the specialization of anatomically distinct brain areas.

[Clinical implications of high cobalamin blood levels for internal medicine]. / Implications cliniques de la découverte d'une hypervitaminémie B12 en médecine interne.

PURPOSE: The high incidence of cobalamin (vitamin B12) deficiency results in frequent dosages of this vitamin in a department of internal medicine may reveal paradoxically high blood levels of cobalamin. The objective of the study was to estimate underlying diseases and potential diagnostic relevance of high cobalamin blood levels in internal medicine. METHODS: A retrospective study was conducted, including in-patients from December 2005 to July 2006 presenting high cobalamin blood levels, as determined with our laboratory normal values (200-950 pg/mL). RESULTS: High cobalamin blood level is not unusual (18.5% of all dosages) and, most of time, it is associated with one or several diseases, among which acute and chronic liver diseases (often of alcoholic origin), various neoplasias, malignant hemopathies (myelodysplasia, myeloproliferative diseases, multiple myeloma), renal insufficiency and transient hematologic abnormalities (neutrophilic hyperleucocytosis, hypereosinophilia). Vitamin B12 supplementation and chronic myeloid leukemia represent less than 5% of all hypervitaminemia. There is no correlation between the level of cobalamin blood level and the number of underlying diseases for each patients. However, very high cobalamin blood levels (>1275 pg/mL) are significantly associated to malignant hemopathies (p<0.05). It is noteworthy that most of diagnosed neoplasia were unknown and at a non-metastatic stage. CONCLUSION: Very high cobalamin blood levels are significantly associated to malignant hemopathies among the population of a department of internal medicine. Referent laboratory should actively advertise the numerous diseases involved with high cobalamin blood levels.

n-3 Fatty acids modulate brain glucose transport in endothelial cells of the blood-brain barrier.

We have previously shown that glucose utilization and glucose transport were impaired in the brain of rats made deficient in n-3 polyunsaturated fatty acids (PUFA). The present study examines whether n-3 PUFA affect the expression of glucose transporter GLUT1 and glucose transport activity in the endothelial cells of the blood-brain barrier. GLUT1 expression in the cerebral cortex microvessels of rats fed different amounts of n-3 PUFA (low vs. adequate vs. high) was studied. In parallel, the glucose uptake was measured in primary cultures of rat brain endothelial cells (RBEC) exposed to supplemental long chain n-3 PUFA, docosahexaenoic (DHA) and eicosapentaenoic (EPA) acids, or to arachidonic acid (AA). Western immunoblotting analysis showed that endothelial GLUT1 significantly decreased (-23%) in the n-3 PUFA-deficient microvessels compared to control ones, whereas it increased (+35%) in the microvessels of rats fed the high n-3 PUFA diet. In addition, binding of cytochalasin B indicated that the maximum binding to GLUT1 (Bmax) was reduced in deficient rats. Incubation of RBEC with 15 microM DHA induced the membrane DHA to increase at a level approaching that of cerebral microvessels isolated from rats fed the high n-3 diet. Supplementation of RBEC with DHA or EPA increased the [(3)H]-3-O-methylglucose uptake (reflecting the basal glucose transport) by 35% and 50%, respectively, while AA had no effect. In conclusion, we suggest that n-3 PUFA can modulate the brain glucose transport in endothelial cells of the blood-brain barrier, possibly via changes in GLUT1 protein expression and activity.

Motor cortex stimulation for neuropathic pain.

Since the initial publication of Tsubokawa in 1991, epidural motor cortex stimulation (MCS) is increasingly reported as an effective surgical option for the treatment of refractory neuropathic pain although its mechanism of action remains poorly understood. The authors review the extensive literature published over the last 15 years on central and neuropathic pain. Optimal patient selection remains difficult and the value of pharmacological tests or transcranial magnetic stimulation in predicting the efficacy of MCS has not been established. Pre-operative functional magnetic resonance imaging (fMRI), 3-dimensional volume MRI, neuronavigation and intra-operative neurophysiological monitoring have contributed to improvements in the technique for identifying the precise location of the targeted motor cortical area and the correct placement of the electrode array. MCS should be considered as the treatment of choice in post-stroke pain, thalamic pain or facial anesthesia dolorosa. In brachial plexus avulsion pain, it is preferable to propose initially dorsal root entry zone (DREZ)-tomy; MCS may be offered after DREZotomy has failed to control the pain. In our experience, the results of MCS on phantom limb pain are promising. In general, the efficacy of MCS depends on: a) the accurate placement of the stimulation electrode over the appropriate area of the motor cortex, and b) on sophisticated programming of the stimulation parameters. A better understanding of the MCS mechanism of action will probably make it possible to adjust better the stimulation parameters. The conclusions of multicentered randomised studies, now in progress, will be very useful and are likely to promote further research and clinical applications in this field.

Chronic motor cortex stimulation for phantom limb pain: a functional magnetic resonance imaging study: technical case report.

OBJECTIVE AND IMPORTANCE: Chronic motor cortex stimulation has provided satisfactory control of pain in patients with central or neuropathic trigeminal pain. We used this technique in a patient who experienced phantom limb pain. Functional magnetic resonance imaging (fMRI) was used to guide electrode placement and to assist in understanding the control mechanisms involved in phantom limb pain. CLINICAL PRESENTATION: A 45-year-old man whose right arm had been amputated 2 years previously experienced phantom limb pain and phantom limb phenomena, described as the apparent possibility of moving the amputated hand voluntarily. He was treated with chronic motor cortex stimulation. INTERVENTION: Data from fMRI were used pre- and postoperatively to detect shoulder and stump cortical activated areas and the "virtual" amputated hand cortical area. These sites of preoperative fMRI activation were integrated in an infrared-based frameless stereotactic device for surgical planning. Phantom limb virtual finger movement caused contralateral primary motor cortex activation. Satisfactory pain control was obtained; a 70% reduction in the phantom limb pain was achieved on a visual analog scale. Postoperatively and under chronic stimulation, inhibiting effects on the primary sensorimotor cortex as well as on the contralateral primary motor and sensitive cortices were detected by fMRI studies. CONCLUSION: Chronic motor cortex stimulation can be used to relieve phantom limb pain and phantom limb phenomena. Integrated by an infrared-based frameless stereotactic device, fMRI data are useful in assisting the neurosurgeon in electrode placement for this indication. Pain control mechanisms and cortical reorganization phenomena can be studied by the use of fMRI.

Chronic motor cortex stimulation for phantom limb pain: correlations between pain relief and functional imaging studies.

Chronic motor cortex stimulation (CMCS) has provided satisfactory control of pain in patients with central or trigeminal neuropathic pain. We used this technique in 3 patients with intractable phantom limb pain after upper limb amputation. Functional magnetic resonance imaging (fMRI) correlated to anatomical MRI permitted frameless image guidance for electrode placement. Pain control was obtained for all the patients initially and the relief was stable in 2 of the 3 patients at 2 year follow-up. CMCS can be used to relieve phantom limb pain. fMRI data are useful in assisting the neurosurgeon in electrode placement for this indication.

Methodological and technical issues for integrating functional magnetic resonance imaging data in a neuronavigational system.

OBJECTIVE: The aim of this article was to analyze the technical and methodological issues resulting from the use of functional magnetic resonance image (fMRI) data in a frameless stereotactic device for brain tumor or pain surgery (chronic motor cortex stimulation). METHODS: A total of 32 candidates, 26 for brain tumor surgery and six chronic motor cortex stimulation, were studied by fMRI scanning (61 procedures) and intraoperative cortical brain mapping under general anesthesia. The fMRI data obtained were analyzed with the Statistical Parametric Mapping 99 software, with an initial analysis threshold corresponding to P < 0.001. Subsequently, the fMRI data were registered in a frameless stereotactic neuronavigational device and correlated to brain mapping. RESULTS: Correspondence between fMRI-activated areas and cortical mapping in primary motor areas was good in 28 patients (87%), although fMRI-activated areas were highly dependent on the choice of paradigms and analysis thresholds. Primary sensory- and secondary motor-activated areas were not correlated to cortical brain mapping. Functional mislocalization as a result of insufficient correction of the echo-planar distortion was identified in four patients (13%). Analysis thresholds (from P < 0.0001 to P < 10(-12)) more restrictive than the initial threshold (P < 0.001) had to be used in 25 of the 28 patients studied, so that fMRI motor data could be matched to cortical mapping spatial data. These analysis thresholds were not predictable preoperatively. Maximal tumor resection was accomplished in all patients with brain tumors. Chronic motor cortex electrode placement was successful in each patient (significant pain relief >50% on the visual analog pain scale). CONCLUSION: In brain tumor surgery, fMRI data are helpful in surgical planning and guiding intraoperative brain mapping. The registration of fMRI data in anatomic slices or in the frameless stereotactic neuronavigational device, however, remained a potential source of functional mislocalization. Electrode placement for chronic motor cortex stimulation is a good indication to use fMRI data registered in a neuronavigational system and could replace somatosensory evoked potentials in detection of the central sulcus.

[Cancer of the ethmoid sinus]. / Cancer de l'ethmoïde.

Ethmoid sinuses are located at the level of the anterior skull base. Seventy to 80% of the ethmoid sinus malignant tumors are adenocarcinomas. Wood dust exposure is a carcinogen agent to ethmoid adenocarcinoma. More than 90% of patients with ethmoid adenocarcinoma are woodworkers. Craniofacial computed tomography scan and magnetic resonance imaging are always performed before treatment. It is always a multidisciplinary treatment including surgical resection followed by external radiation therapy. Some authors recommend a neoadjuvant chemotherapy. A total ethmoidectomy including the cribriform plate through a transcranial subfrontal approach is the best surgical technique. Local recurrence is the most frequent cause of failure; 5-year survival of patients with ethmoid adenocarcinoma is around 50%. A regular follow-up including clinical and radiological examination is always required.

Epidemiology and prophylaxis of endemic goitre in the Bwa village of Sirao (Mali).

A study was conducted in Mali, in some villages exposed to iodine deficiency disorders (IDD). To treat and, above all, prevent endemic goitre, Lipiodol UF was dispensed in two ways: by intra-muscular injection (475 mg I) or by oral administration (48 mg I to 240 mg I). In two cases, hormone levels regained normal values and thyroid hypertrophies regressed significantly. Nevertheless, the impact of the treatment on the size of the goitres seems to be in favour of injections; which is probably due to the fact that in the village which received Lipiodol UF per os, many goitres were nodular.

Interstitial laser thermotherapy: developments in the treatment of small deep-seated brain tumors.

New technical advances have made feasible the utilization of laser to destroy deep-seated brain tumors under real-time monitoring. Experience with interstitial laser thermotherapy (ILTT) in animal and clinical studies has been obtained. These studies are summarized and the future potential of ILTT in neurosurgery is discussed.

Cisplatin-based neoadjuvant chemotherapy and combined resection for ethmoid sinus adenocarcinoma reaching and/or invading the skull base.

OBJECTIVE: To review our experience with cisplatin-based neoadjuvant chemotherapy before en bloc resection via a combined neurosurgical and transfacial approach for ethmoid sinus adenocarcinoma reaching and/or invading the skull base. DESIGN: Case series. SETTING: A tertiary care center and university teaching hospital. PATIENTS: Twenty-two patients with primary untreated ethmoid sinus adenocarcinoma reaching and/or invading the skull base consecutively treated between 1984 and 1992 with cisplatin-based neoadjuvant chemotherapy and combined neurosurgical and transfacial approach. MAIN OUTCOME MEASURES: Statistical analysis of survival, local control, nodal recurrence, distant metastasis, and metachronous second primary tumor incidence based on the Kaplan-Meier actuarial method. Univariate analysis was performed to analyze the relationships between various factors, survival, and local recurrence. Clinical response, histological response, toxic effects of chemotherapy, and postoperative course were also reported. RESULTS: The Kaplan-Meier 3-year survival, local control, nodal recurrence, and distant metastasis estimates were 68.1%, 65.7%, 5.3%, and 10%, respectively. Metachronous second primary tumor was not encountered in our series. Survival was statistically more likely to be reduced in patients with intrasphenoidal tumor extent (P = .04) and local recurrence (P = .01). Local recurrence was statistically more likely in patients with intrasphenoidal tumor extent (P = .002) and no response to cisplatin-based neoadjuvant chemotherapy (P = .03). CONCLUSIONS: The results achieved suggest that cisplatin-based neoadjuvant chemotherapy before combined neurosurgical and transfacial approach should be further investigated for the treatment of ethmoid sinus adenocarcinoma reaching and/or invading the skull base.

Endometrial laser interstitial hyperthermy: a potential modality for endometrial ablation.

This study was undertaken to evaluate the efficacy and safety of an intrauterine device designed for endometrial ablation by Nd-YAG laser interstitial hyperthermy. Eight hysterectomy specimens were treated in vitro with an output power of 30 W for 5 minutes; tissue temperatures, recorded by thermocouples, were plotted to draw time-temperature and time-distance curves. As a preliminary series, ten patients were treated, with the first five subjected to local temperature monitoring; all ten were followed-up for 6-17 months. Immediate and delayed (6 weeks) histologic data were obtained. The intramural temperature at 6 mm from the fibers ranged from 55-60C). In vivo, the cooling effect of the arterial blood flow lowered the serosal temperatures under 41C. The histologic data and the hysterographic pictures suggest that endometrial ablation was effective. This new device does not require distending medium, hysteroscopic control, or high-powered Nd-YAG laser machines. Preliminary long-term results suggest that the device could be used for endometrial ablation.

Treatment by iodized oil (Lipiodol UF) of a population in Mali suffering from endemic goiter.

In order to reduce the prevalence of goiter in a village of Mali liable to iodine deficiency, an iodized product (Lipiodol Ultra Fluide) was orally administered to their inhabitants. Taking into account a series of demographic variables and goiter types, a protocol was conducted using Lipiodol at three different dosage levels. Six months after the treatment, the hormone levels regained normal values, whereas only the smallest dose reduces the volume of goiters significantly.

Interstitial laser thermotherapy in neurosurgery: a review.

One of the most recent laser treatment modalities in neurosurgery is interstitial laser thermotherapy (ILTT). In this review, experimental and clinical studies concerning intracranial ILTT are discussed. Two methods for intra-operative control of the laser induced lesions are described; i.e., computer-controlled power delivery, using a thermocouple that is positioned interstitially at the periphery of the tumour to maintain the desired temperature at that point, and MRI, to visualise the extent of the thermal lesions induced by ILTT. The results show that ILTT using a Nd: YAG laser is easy and relatively effective in the treatment of small deep-seated brain tumours with minimal risk and complications. This review is concluded with suggestions for further improvement of this treatment modality.

Experimental and clinical standards, and evolution of lasers in neurosurgery.

From initial experiments of ruby, argon and CO2 lasers on the nervous system so far, dramatic progress was made in delivery systems technology as well as in knowledge of laser-tissue interaction effects and hazards through various animal experiments and clinical experience. Most surgical effects of laser light on neural tissue and the central nervous system (CNS) are thermal lesions. Haemostasis, cutting and vaporization depend on laser emission parameters--wavelength, fluence and mode--and on the exposed tissues optical and thermal properties--water and haemoglobin content, thermal conductivity and specific heat. CO2 and Nd-YAG lasers have today a large place in the neurosurgical armamentarium, while new laser sources such as high power diode lasers will have one in the near future. Current applications of these lasers derive from their respective characteristics, and include CNS tumour and vascular malformation surgery, and stereotactic neurosurgery. Intracranial, spinal cord and intra-orbital meningiomas are the best lesions for laser use for haemostasis, dissection and tissue vaporization. Resection of acoustic neuromas, pituitary tumours, spinal cord neuromas, intracerebral gliomas and metastases may also benefit from lasers as accurate, haemostatic, non-contact instruments which reduce surgical trauma to the brain and eloquent structures such as brain stem and cranial nerves. Coagulative lasers (1.06 microns and 1.32 microns Nd-YAG, argon, or diode laser) will find an application for arteriovenous malformations and cavernomas. Any fiberoptic-guided laser will find a use during stereotactic neurosurgical procedures, including image-guided resection of tumours and vascular malformations and endoscopic tumour resection and cysts or entry into a ventricle. Besides these routine applications of lasers, laser interstitial thermotherapy (LITT) and photodynamic therapy (PDT) of brain tumours are still in the experimental stage. The choice of a laser in a neurosurgical operating room implies an evaluation of the laser use (applications, frequency), of the available budget and costs--including purchase, maintenance and staff training--, and material that will be necessary: unit, peripherals, safety devices and measures, training programme. Future applications of lasers in neurosurgery will come from technological advances and refined experimental applications. The availability of new wavelength, tunable, small sized and "smart" laser units, will enlarge the thermal and non-thermal interactions between laser energy and neural tissue leading to new surgical applications. Tissue photo-ablation, photohynamic therapy using second generation of photosensitizers, updated thermotherapy protocols, are current trends for further use of lasers in neurosurgery.

Ethmoid sinus carcinomas: results and prognosis after neoadjuvant chemotherapy and combined surgery--a 10-year experience.

From June 1982 to June 1992, 144 ethmoido-sphenoido-orbital tumors have been referred to the neurosurgical department of Ste Anne Hospital. One hundred five of them were malignant lesions, among which 83 were included into our therapeutic protocol (1) neo-adjuvant chemotherapy (CDDP + 5-FU), (2) combined surgical procedure (subfrontal and transfacial), (3) postoperative radiotherapy. Fifty nine percent of the patients had no response to chemotherapy; 19% had a partial response (reduction of the tumoral volume > 50% and < 100%), 22% had a complete response. One patient had an immediate and transient postoperative rhinorrhea responsible for meningitis (acinetobacter) that was cured after a 3-day treatment. Four patients had postoperative meningitis without any cerebrospinal fluid leakage; they were also cured. Five patients had a local suppuration that was treated by subcutaneous drainage (n = 1) or the removal of the cranial basis graft (n = 4). Oncologic results are presented for only adenocarcinomas (n = 63) because they represent the only population of this series large enough to assure significant statistical figures. The global actuarial survival rate was 53% at 3 years and 42.5% at 5 years. The 5-year actuarial survival rate was 80% for T1 tumors, 60% for T2, 40% for T3, and 25% for T4. Patients with an intracranial extension had a 3-year survival rate of 19%; none survived after 4-year follow-up. Neo-adjuvant chemotherapy seemed to influence the survival: 100% survival rate at 5 and 10 years for the complete responders. We discuss the opportunity of intraorbital exenteration, the indications, and the limits of combined surgery. We emphasize the importance of neo-adjuvant chemotherapy and of combined surgical procedures, even when the patients are complete responders to chemotherapy: complete responders who had only a transfacial approach have a 5-year actuarial survival rate of 80% (instead of 100% when a combined procedure was performed). Those who were not operated primarily recurred within 3 years and then had to be operated. We propose to follow such a combined surgery for all large ethmoidal cancers (T3 and T4) and for small tumors (T1 and T2) developed superiorly and posteriorly. Anterior T1 and T2 tumors should be operated through a single transfacial route.

[Stereotaxic laser interstitial thermotherapy. A new alternative in the therapeutic management of some brain tumors]. / La thermothérapie interstitielle laser stéréotaxique. Une nouvelle alternative dans la prise en charge thérapeutique de certaines tumeurs cérébrales.

Laser Interstitial Thermo Therapy (ITT) is a new procedure which has been performed only a few times in our department as well as in foreign services. The aim of an ITT is to increase the temperature of a tumoral target which has been perfectly determined stereotactically. In the center of the target, i-e at the extremity of the laser fibre, temperature reaches 80 degrees 90 degrees C and creates a coagulation necrosis. At the periphery of the target, temperature must be 41 degrees-43 degrees C so as to create a selective lesion of the pathological tissue due to proteinic and enzymatic denaturation. The authors present their experience based on 8 patients who underwent an ITT between June 1990 and October 1991. A stereotactic determination of the tumor is first performed; then two routes are determined for the laser-fibre (Nd-YAG 1.06 microns, fiber diameter: 400 mu) and for the thermic electrode. The ITT itself is performed a few days later (P = 3-5w, time: 800-1200 seconds). Laser heat effects are monitored with MRI controls (H5, H24, D8 then monthly). The authors insist on the importance of a long follow-up so as to be sure of the complete inocuity of such a treatment. It is the only way to broaden and develop laser-ITT procedures as therapeutic alternatives for certain deep-seated intracerebral tumors.

[Combined approach to malignant tumors of the ethmoid and other paranasal sinuses. Principles and results]. / Les abords combinés des tumeurs malignes de l'ethmoïde et autres sinus paranasaux Principes et résultats.

The authors present their experience concerning combined transfacial and neurosurgical procedures in the treatment of carcinomas of the ethmoid sinuses. 109 ethmoid-spheno-orbital tumors were treated at our department from 1982 to 1990: 85 were located into the ethmoidal and/or sphenoidal sinuses; 78 of these were malignant. Among the 65 ethmoidal carcinomas which were operated through a combined route, 48 underwent an induction chemotherapy and 19 a post-operative radiotherapy. The surgical technique is detailed, mostly the intra-cranial approach and the reconstruction of the cranial basis. Clinical results, and particularly the actuarial survival rates are discussed. The 5-year actuarial survival rate is 40% for all first hand ethmoidal adenocarcinomas. The figure reaches 52% for the patients without intra-cranial extension. At last, the 5-year actuarial survival rate is 100% for patients having a complete clinical response to induction chemotherapy.