A reappraisal of the value of lateral spread response monitoring in the treatment of hemifacial spasm by microvascular decompression.

BACKGROUND: Lateral spread response (LSR) to the electrical stimulation of a facial nerve branch is a specific electrophysiological feature of primary hemifacial spasm (HFS). The curative treatment of HFS is based on surgical microvascular decompression (MVD). However, the outcome of this procedure is not always satisfactory. OBJECTIVE: To evaluate the correlation between intraoperative LSR changes and the short- and long-term postoperative clinical outcome following MVD. METHODS: Thirty-two consecutive patients with primary HFS treated by MVD performed with intraoperative LSR monitoring were retrospectively included. The patients were assessed for the presence of HFS and surgical complications at 1 day, 1 month and 6 months after surgery. The long-term clinical result was assessed between 1 and 10 years (mean 5.4 years) using a self-report questionnaire. RESULTS: Patients were divided into three groups based on intraoperative LSR changes: (1) in 15 patients, LSRs were present before incision and disappeared after MVD (47%); (2) in nine patients, LSRs were present before incision but persisted despite MVD (28%); (3) in eight patients, LSRs were absent before surgery and remained so after the procedure (25%). Intraoperative LSR abolition during the MVD procedure correlated with HFS relief in the long term (p<0.0001, Fisher exact test), but not on the first day after surgery (p = 0.3564). CONCLUSIONS: Monitoring MVD by recording LSRs intraoperatively could be of value not only to indicate the resolution of the vasculonervous conflict at the end of surgery, but also to predict a successful clinical outcome in the long term after the surgical intervention.

[Neurosurgical treatment of vago-glossopharyngeal neuralgia]. / Traitement neurochirurgical de la névralgie vago-glossopharyngienne.

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.

[Vascular decompression as treatment of essential arterial hypertension]. / Décompression vasculaire pour traitement de l'hypertension artérielle essentielle.

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.

[Neurosurgical treatment of primary hemifacial spasm with microvascular decompression]. / Traitement neurochirurgical du spasme hémifacial primaire par décompression vasculaire microchirurgicale.

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.

[Algorithms for neurosurgical treatment of trigeminal neuralgia]. / Arbre décisionnel pour le traitement neurochirurgical de la névralgie du trijumeau.

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.

[Clinical aspects of trigeminal neuralgia]. / Aspects cliniques de la névralgie du trijumeau.

Primary trigeminal neuralgia, termed "classical" in the international nomenclature, is an epilepsy-like disease. Diagnosis is easy when the disorder typical in presentation, based on clinical features and responsiveness to anticonvulsants. However, diagnosis can be difficult when atypical and/or in the long-duration forms. Furthermore, trigeminal neuralgia - even if typical in its clinical aspects - may be caused by a specific lesion and reveal a pathology. In other words, it may be symptomatic (secondary). Imaging, especially MRI, is of prime importance in identifying the cause and guiding the appropriate treatment.

[Treatment of trigeminal neuralgia with microvascular decompression]. / Traitement de la névralgie trigéminale par décompression vasculaire microchirurgicale.

Pure microvascular decompression (MVD) can cure (that is, no pain, no medication) primary trigeminal neuralgia (TN) caused by vascular compression in 75% of patients (90% when compression is pronounced), according to a Kaplan-Meier survival study at 15 years. MRI with high resolution evidences neurovascular conflicts with good reliability. The results were found to be significantly better when the prosthesis implanted to maintain the compressive vessel away was not touching the nerve. This argues in favor of a real decompressive mechanism of the MVD procedure, rather than a conduction block. Because pure MVD generally does not produce hypoesthesia in the painful territory, MVD is the first surgical therapeutic option for patients with neuralgia resistant to anticonvulsive medications.

[Balloon compression for the treatment of trigeminal neuralgia]. / Traitement de la névralgie trigéminale par la compression par ballon.

The authors present a retrospective study of 121 patients treated with balloon compression of the rootlets behind the Gasser ganglion from 1995 to 2007. The inclusion criteria were drug-resistant idiopathic trigeminal neuralgia. The authors described the surgical technique and compared their results with results from the literature. The following parameters were compared: technical success, pain relief and recurrence, and complications. Balloon compression is considered in the literature to be a safer procedure than other percutaneous surgeries, especially for postoperative sensitive disorders. The best indications seem to be trigeminal neuralgia in older patients or pain due to multiple sclerosis and neuralgia involving the V1 territory. These conclusions should be confirmed by larger series, a longer follow-up (> 5 years) and statistically better analysis.

[Treatment of trigeminal neuropathic pain by motor cortex stimulation]. / Traitement des douleurs trigéminales neuropathiques par stimulation corticale.

The neurosurgical procedures currently available for the treatment of trigeminal neuralgia can induce trigeminal neuropathic pain. Severe forms of trigeminal neuropathic pain correspond to the classical facial anesthesia dolorosa, whose treatment is known to be very difficult. Chronic stimulation of the ventral posterolateral nucleus (VPL) of the thalamus was, in the past, the only neurosurgical therapy available to treat this complication. The long-term results have been disappointing, which opened the field to the development of other techniques, including stimulation of the motor cortex for which there is now sufficient experience showing long-term results that are satisfactory in more than 70% of patients. Meanwhile, some authors have proposed directly stimulating the nerve branches concerned, such as the supraorbital nerve, or discussing indications for thalamic stimulation. In this chapter, only the cortical stimulation procedure will be developed.

[Cranial nerve functional neurosurgery: evaluation of surgical practice]. / La neurochirurgie fonctionnelle des nerfs crâniens Evaluation de l'activité

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.

Motor cortex rTMS in chronic neuropathic pain: pain relief is associated with thermal sensory perception improvement.

BACKGROUND: Improvement in sensory detection thresholds was found to be associated with neuropathic pain relief produced by epidural motor cortex stimulation with surgically implanted electrodes. OBJECTIVE: To determine the ability of repetitive transcranial magnetic stimulation (rTMS) of the motor cortex to produce similar sensory changes. METHODS: In 46 patients with chronic neuropathic pain of various origins, first-perception thresholds for thermal (cold, warm) and mechanical (vibration, pressure) sensations were quantified in the painful zone and in the painless homologue contralateral territory, before and after rTMS of the motor cortex corresponding to the painful side. Ongoing pain level was also scored before and after rTMS. Three types of rTMS session, performed at 1 Hz or 10 Hz using an active coil, or at 10 Hz using a sham coil, were compared. The relationships between rTMS-induced changes in sensory thresholds and in pain scores were studied. RESULTS: Subthreshold rTMS applied at 10 Hz significantly lowered pain scores and thermal sensory thresholds in the painful zone but did not lower mechanical sensory thresholds. Pain relief correlated with post-rTMS improvement of warm sensory thresholds in the painful zone. CONCLUSIONS: Thermal sensory relays are potentially dysfunctioning in chronic neuropathic pain secondary to sensitisation or deafferentation-induced disinhibition. By acting on these structures, motor cortex stimulation could relieve pain and concomitantly improve innocuous thermal sensory discrimination.

Involvement of electrophysiological localization of the subthalamic nucleus in deep brain stimulation for Parkinson's disease.

We studied the involvement of the electrophysiological localization of the subthalamic nucleus (NST) using a multi-unit recording technique by means of semi-microelectrode in a set of thirty Parkinson's patients who benefited from a bilateral stimulation of the NST and who were operated on under local or general anesthesia. The multi-unit recording technique by means of semi-microelectrodes appeared efficient, capable of improving the localization of the NST and leading to improvement in clinical results. We believe that the use of our technique will allow for time savings while providing good results, and that the choice of the angle of the trajectory will allow for improved localization of the NST and thus improved clinical results.

Pain relief induced by repetitive transcranial magnetic stimulation of precentral cortex.

Chronic electrical stimulation of the precentral (motor) cortex using surgically implanted electrodes is performed to treat medication-resistant neurogenic pain. The goal of this placebo-controlled study was to obtain such antalgic effects by means of a non-invasive cortical stimulation using repetitive transcranial magnetic stimulation (rTMS). Eighteen patients with intractable neurogenic pain of various origins were included and underwent a 20 min session of either 10 Hz, 0.5 Hz or* sham rTMS over the motor cortex in a random order. A significant decrease in the mean pain level of the series was obtained only after 10 Hz rTMS. This study shows that a transient pain relief can be induced by 10 Hz rTMS of the motor cortex in some patients suffering from chronic neurogenic pain.

Extradural and hourglass cervical neurinomas: the vertebral artery problem.

Eleven cases of cervical neurinomas with an extradural component were operated on with control of the vertebral artery as the first step of the surgical procedure. The lateral anterior approach was used first in each case with excellent results. In the case of hourglass tumors (seven cases), a complementary posterior approach was performed to remove the intradural portion. Primary control of the vertebral artery in cases of extradural or hourglass neurinoma is a logical and safe procedure in the attempt to achieve complete and bloodless tumor removal.

A technique for stereotactic aspiration of deep intracerebral hematomas under computed tomographic control using a new device.

A new device, modified from the Nucleotome (Surgical Dynamics, Alameda, CA), was used for stereotactic aspiration of deep brain hematomas. Real-time monitoring by computed tomography allows a very safe procedure, and the risk of aspirating the surrounding brain is avoided. The technique was applied in 13 cases of deep brain hematomas. The intraoperative computed tomographic scan demonstrated that the mass effect was always immediately improved. Aspiration was stopped when the midline shift disappeared or was dramatically reduced. For most of the cases, a total aspiration of the hematoma was not needed (mean value of the aspiration rate of 71, 5%). No rebleeding and no complication related to the technique was observed. This technique was easily performed in emergency conditions.

Cortical stimulation and epileptic seizure: a study of the potential risk in primates.

OBJECTIVE: The recent successful development of chronic stimulation of the motor cortex as a treatment for neuropathic and central pain does not exclude the possibility of eventual side effects, such as epileptic seizure or a lowering of the epileptic threshold. This study evaluates the behavioral and electroencephalographic impact of this treatment in three normal monkeys. RESULTS: None of the monkeys presented epileptic behavior or abnormal electroencephalographic activity at parameters of stimulation currently used in clinical series, i.e., frequency and pulse duration of approximately 40 Hz and 90 microseconds, respectively, and an intensity just under the threshold for inducing muscle twitch in painful areas. Higher intensities did, however, induce reversible epileptic seizure. There was, nonetheless, no modification of the epileptic threshold, because even after these seizures, intermittent light stimulation elicited no abnormal electroencephalographic activity. CONCLUSION: It thus seems that motor cortex stimulation does not induce epileptic complications when the classic clinical criteria of stimulation are respected. Nevertheless, it would be wise to subject candidates for implantation to intermittent light stimulation before and after a period of stimulation to ascertain the innocuousness of the cortical stimulation.

Endoscopic management of colloid cysts.

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.

Failure of a Heifetz aneurysm clip.

A 16-year-old girl died from an acute subarachnoid hemorrhage following the fracture of a blade of a Heifetz aneurysm clip. The clip was manufactured from 17-7PH steel, which on metallurgical testing was found to be highly sensitive to intergranular corrosion. The fracture mechanism was stress corrosion, brought on by the combination of a stress load, an electrolytic environment, and a susceptible steel.

A new device for endoscopic third ventriculostomy.

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.

Percutaneous endoscopic treatment of suprasellar arachnoid cysts: ventriculocystostomy or ventriculocystocisternostomy? Technical note.

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.