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.

[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.

[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.

[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.

Haemorrhagic acoustic neuroma with features of a vascular malformation. A case report.

A 55-year-old man with hearing loss presented with vertigo and vomiting. CT tomography and MRI demonstrated a cerebellopontine angle mass with foci of haemorrhage. An angiomatous tumour, with large abnormal veins adhering to the capsule, was completely removed. Histologically, the tumour was an acoustic neuroma with abnormal vascularisation and limited intratumoral haemorrhage.

[Peripheral neurotomy in the treatment of spasticity. Indications, techniques and results in the lower limbs]. / Les neurotomies périphériques dans le traitement de la spasticité. Indications, technique et résultats aux membres inférieurs.

INTRODUCTION: The aim of this study was to review the principle of peripheral neurotomy for the treatment of lower limb spasticity. The importance of clinical assessment is stressed (with particular focus on motor block) for determining the best surgical indications. MATERIAL AND METHOD: Between 1989 and 1997, 392 neurotomies were performed in 277 patients in the neurosurgery department of the Henri Mondor Hospital, Créteil, France. Surgical technique consisted in partial and segmental resection, involving each motor collateral branch of muscles with excessive spasticity. For the lower limb, the most frequent neurotomy was performed on collateral branches of the posterior tibial nerve (66%) for the spastic foot. RESULTS: Preoperative motor block provided the advantage of "mimicking" the effect of the neurotomy and therefore gave the patients an idea of the expected result of surgery. For the spastic foot, posterior neurotomy led to the disappearance of ankle clonus in all patients. When antagonist muscles were present, splints were no longer needed after neurotomy. Cinematic analysis showed that tibial neurotomy improved angular variations of the second rocker of the ankle during stance. CONCLUSION: Peripheral neurotomies are simple and safe procedures for the treatment of lower limb spasticity and should be routinely used in general neurosurgery practice.

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.

Physiological effects of selective tibial neurotomy on lower limb spasticity.

OBJECTIVES: To assess by electrophysiology the effect of tibial selective neurotomy on muscle imbalance of the spastic ankle. METHOD: The amplitudes of the H reflexes, M responses (muscle contractions recorded after stimulation of the tibial nerve), and Hmax:Mmax ratio were recorded in 12 patients with chronic lower limb spasticity, before and one month after tibial selective neurotomy. Recordings were done on medial and lateral gastrocnemius and soleus muscles. Clinical evaluation was done with both global (Held's score) and analytical tests (step measurements, gait velocity, and ankle angulation during active and passive movements). RESULTS: After neurotomy, gait improved in all patients. Held's score of spasticity was better in all patients. Active dorsiflexion of the ankle was unchanged in three patients, but the others improved by 5 degrees to 12 degrees. Hmax, Mmax, and Hmax:Mmax ratios were lower. The Hmax on the gastrocnemius muscle, clinical strength, Mmax of all the muscles, and Hmax:Mmax ratio for the soleus and lateral gastrocnemius muscle were significantly lower after surgery. CONCLUSION: There was an improvement of clinical and electrophysiological spastic indices after selective tibial neurotomy. Neurotomy acted not only on motor neurons by decreasing strength, but also the reflex enlargement by decreasing sensory afferents.

Is electrostimulation preferable to surgery for upper limb ataxia?

Ataxic syndromes of the upper limbs are observed in various situations but are usually a result of lesions involving the efferent pathways of the cerebellum, the superior cerebellar peduncles and midbrain. The commonest causes are multiple sclerosis, brain injury and focal neoplastic or vascular lesions. Cerebellar tremor, which usually comprises a postural and intentional component, is the commonest clinical form. In this review, we assess the value of the various surgical techniques in the treatment of this particular form of ataxia of the upper limbs.

Epithelioid Schwannoma of the acoustic nerve.

A 25-year-old woman presented with left progressive deafness due to an intracranial tumor of the cerebello-pontine angle. Biopsy and subsequent total surgical excision indicated origin from the acoustic nerve. Histologically, the tumor showed typical feature of Schwannoma associated with a population of epithelioid cells. Three years after surgery no local invasion, no relapse, and no metastasis were noted. Immunohistochemistry showed a strong positivity for S100 protein in the cytoplasm of Schwannian and epithelioid tumoral cell components. This positivity in the epithelioid cells correspond to a well differentiated cell population derived from a Schwann cell precursor explaining the benign course of the tumor. In the absence of similar cases of epithelioid Schwannoma of the acoustic nerve in literature, we will discuss the differential diagnosis, potential evolutivity, and origin of the epithelioid cells.

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.

Long-term outcome of unilaterally transplanted parkinsonian patients. I. Clinical approach.

Five patients with Parkinson's disease, unilaterally transplanted with foetal mesencephalic cells into putamen (n=1) or putamen and caudate (n=4), were followed throughout a period of 15-36 months after surgery, according to the recommendations of the core assessment programme for intracerebral transplantations (CAPIT). All these patients exhibited an increase in the fluorodopa uptake in the grafted putamen, which was most significant in the first and last patient of the series. Long-term bilateral improvement of skilled hand movements was observed, starting between the third and sixth month after grafting, and confirmed by the statistical analysis of CAPIT timed tests. A mild to moderate effect on the amount of 'off' time and 'on-off' fluctuations was observed, whereas, apart from one case, no other clear effect on gait, walking and speech was found. One patient included in the study, already suffering slight cognitive impairment, clearly exhibited progression of a dementia process after surgery. Daily living activities were clearly improved in only one of the other four patients. At the end of the study period, all patients needed L-dopa therapy at a similar or higher dose than before grafting, but, in most of them, other dopaminergic drugs were reduced or stopped. All patients exhibited bilateral dyskinesias before grafting that were greatly decreased in intensity a few months after surgery. Delayed asymmetrical dyskinesias, occurring on the side displaying the better motor improvement, i.e. contralateral to the graft, were observed in three patients. These results suggest that neural transplants may influence two central mechanisms involved in motor function and the onset of dyskinesias. These effects are likely to occur through complex interactions with the post-synaptic dopaminergic receptors. The occurrence of dyskinesias might simply reflect increased presynaptic storage and release of dopamine. Alternatively, it might, in part, represent some other long-term deleterious effect of the graft. Since PET-scan data indicate that the reinnervation obtained is sub-optimal, it will be of interest to obtain a larger and denser reinnervation of the host striatum and to try, thereafter, to reduce the dose of L-dopa.

[Microsurgical vascular decompression in the treatment of facial hemispasm. A retrospective study of a series of 65 cases and review of the literature]. / La décompression vasculaire microchirurgicale dans le traitement du spasme hémifacial. Etude rétrospective d'une série de 65 cas et revue de la littérature.

The results of a series of 65 consecutive patients operated on to relieve hemifacial spasm (HFS) at Pierre Wertheimer Hospital in Lyon and at Henri Mondor Hospital in Creteil, using the same microvascular decompression (MVD) method, are reported. MDV was performed through a retromastoid keyhole approach. A neurovascular conflict (NVC) was found in 62 cases (i.e., 95.5%). The conflicting vessel was the posterior inferior cerebellar artery (PICA) in 23 cases (35.4%), the anterior inferior cerebellar artery (AICA) in 22 cases (33.8%), the vertebro-basilar artery (VBA) with PICA and/or AICA in 13 cases (20%), and VBA alone in 4 cases (3.1%). The conflicting artery was maintained apart from the REZ of VII nerve by interposing a ball made of Teflon fibers and/or a plaque of Dacron. Forty-five patients (69.2%) were totally cured, 16 patients (24.6%) had only a partial (more than 50%) improvement, and in 4 patients (6.2%) surgery failed. Follow-up ranged from 1 month to 13 years (mean: 4 years and 8 months). Important was that in 9 patients, total relief of spasm occurred only secondarily with a delay sometimes as long as one year. Post-operative complications were dominated by: 1) facial nerve deficits in 16 cases (24.6%), of which 14 were transient and 2 were permanent; 2) hearing decrease in 10 cases (15.4%), of which 5 were transient and 5 were permanent. These complications were encountered at the start of the experience and at a time when monitoring of intraoperative brainstem auditory evoked potentials (BAEP) was not routinely done. Our data proved to be consistent with those published in the literature.

Shunt failure in adult hydrocephalus: flow-controlled shunt versus differential pressure shunts--a cooperative study in 289 patients.

BACKGROUND: In order to assess the efficiency of flow-controlled shunts in reducing shunt failure in the treatment of adult hydrocephalus (with a special focus on overdrainage complications), a series of 289 patients was analyzed through a retrospective and comparative study performed in three neurosurgical departments. METHODS: A group of 142 adult patients suffering from hydrocephalus were operated on using a conventional differential pressure (DP) shunt and compared with a group of 147 adult patients operated on using flow-controlled (FC) system (Orbis-Sigma, Cordis). Only the first complication, which required a surgical revision within the first 2 years after shunt implantation, was taken into account for each patient and analyzed using life-table methods. RESULTS: The actuarial risk of shunt infection in the two groups is respectively 8.3% and 10.9% at 1 year (nonsignificant difference). The actuarial risk of mechanical complications at 1 year is 38% for the DP patients and 10% for the FC patients (p = 0.0001); this difference is largely due to a decrease of complications related to overdrainage phenomenon (14/142 subdural collections were observed in the DP group versus 1/147 in the FC group) (p = 0.0001). CONCLUSION: The conclusion of this cooperative and retrospective study is that the use of a flow-controlled system decreases the risk of mechanical complications related to the hydrodynamic properties of the shunts used in the treatment of adult hydrocephalus, especially those related to overdrainage.

[Intra-extracranial meningioma in the cranial vault]. / Les méningiomes intra-extracrâniens de la voûte.

Between 1982 and 1993, 11 cases of intra-extracranial vault meningiomas were treated in Créteil, by the same multidisciplinary team. The average age was 53.5 years and the Karnofsky rating was high (> 80 in 7 cases). Ten of the 11 cases had medial tumours with venous sinus thrombosis occurring in 9 of these. The location of the tumour was frontal in 6 and parietal in 4 patients. Of the medial tumours, 5 (half) were bilateral intracranial lesions. The average duration of symptoms was more than 10 years in four cases, between 1 and 3 years in five, and the diagnosis was made immediately in two patients. MRI coronal sections, after venous contrast injection, allowed diagnosis of the lesion and visualisation of the sinus thrombosis. Embolisation was performed pre-operatively in all cases scheduled to have surgery, resulting in safe excision of the tumour. Surgery was performed in 9 patients with complete tumour removal achieved in 8. Of those who did not undergo surgery, one received radiotherapy and the other died before treatment. The bony defect was covered with cadaveric bone, autogenous bone, coral and methyl-methacrylate in one, two, two and two patients respectively. Complications occurred in 2 cases: extradural secondary infection and CSF rhinorrhea treated with a lumbo-peritoneal shunt. The post-operative Karnofsky rating was greater than 90 in seven cases, 70 in one, and 50 in two cases. After an average follow-up of 4 years, 3 patients had tumor recurrence at 4, 7, and 8 years; the first having a locally malignant character, the second showing radiological recurrence in a case of subtotal removal, and the third a marginal recurrence. Two of the 3 patients underwent further surgery. The malignant case, received radiotherapy but unfortunately a new recurrence occurred 14 months later. As radiotherapy was used in only 3 cases, statistically significant conclusions concerning efficacy cannot be drawn.

[Neurosurgical treatments of chronic pain]. / Traitements neurochirurgicaux de la douleur chronique.

During these last years the methods and the indications of analgesic neurosurgery have respectively changed toward greater multiplicity and more selectivity. The conservative methods of neurostimulation have acquired a prominent place in some types of pain from neuropathic origin. Their aim is to reinforce inhibitory fibre function. Whatever the technique used, stimulation of peripheral nerves, of posterior funiculi of the spinal cord, of the thalamus or the cerebral cortex, it will be effective only if the target structures are not totally, anatomically and functionally, destroyed. Intrathecal morphine administration, has been shown to be useful to control some cancer-induced pain. Lastly, the techniques of interrupting the pathways of pain, achieving greater selectivity in their effects, remain the preferred treatment for some types of localised pain having precise mechanisms.

[Value of the monitoring of the facial nerve in the evaluation of facial function in translabyrinthine surgery for acoustic neuroma]. / Intérêt du monitoring du VII sur la fonction faciale dans la chirurgie translabyrinthique des neurinomes de l'acoustique.

Amongst the 62 patients operated for acoustic neuroma using a translabyrinthine approach, the authors study post operatory results at one month of the facial function according to the "House-Brackmann" classification. The analysis consists in 2 homogeneous and comparable series of 34 and 28 patients having benefited or not of a per operatory monitoring of the facial nerve with "NIM 2" neuro monitor. Without distinction of the tumoral sizes 76% of patients show a good facial result when monitorized against 60.7% when not. According to the tumoral size monitoring becomes more interesting: also you will find better results in the monitorized serial (71%) against 29% without. Other factors concerning the facial post operatory functions are also analysed by authors. To the very important part of per operatory monitoring, the anatomical status, microvascularization and physiological state of the nerve al as well as the operator's experience are to be added. All above factors must be considered when evaluating the final post operatory facial result.

[Neurosurgical endoscopy. Diagnostic and therapeutic indications]. / L'endoscopie neurochirurgicale. Indications diagnostiques et thérapeutiques.

An historical review of neurosurgical endoscopy is evocated. The characteristics of the endoscopic material are discussed: flexible or rigid?, length?, diameter?, irrigation?, free-hand manipulation or fixed arm? A rigid neurosurgical endoscope (STORZ) is described which characteristics are the following: 5 mm/3.7 mm ovale diameter, working length of 21 cm (allowing its use under stereotactic conditions), 5F working channel and articulated arm for solid immobilization in the desired position. All the indications of endoscopy are described and illustrated with a series of 48 patients. Indications for diagnosis are rare and summarised in exceptional help for conventional surgery. 80% of the usual indications of endoscopy were represented by third ventriculostomy. The endoscopic guidance brings safety and allows an increasing of the ventriculostomy's indications. Endoscopic fenestrations of arachnoid cyst are described with a particular interest on suprasellar cysts. The other indications are rare: unilateral hydrocephalus, biopsies of intraventricular tumors, puncture of colloid cysts.