Microendoscopic transventricular deep brain stimulation of the anterior nucleus of the thalamus as a safe treatment in intractable epilepsy: A feasibility study

INTRODUCTION

Deep brain stimulation (DBS) of the anterior nucleus of the thalamus (ANT) is proposed in patients with severe intractable epilepsy. When used, the transventricular approach increases the risk of bleeding due the anatomy around the entry point in the thalamus. To avoid such a complication, we used a transventricular microendoscopic technique.

METHODS

We performed a retrospective study of nine adult patients who were surgically treated for refractory epilepsy between 2010 and 2019 by DBS of the anterior thalamic nucleus.

RESULTS

Endoscopy provides a direct visual control of the entry point of the lead in the thalamus through the ventricle by avoiding ependymal vessels. No hemorrhage was recorded and accuracy was systematically checked by intraoperative stereotactic MRI. We reported a responder rate improvement in 88.9% of patients at 1 year and in 87.5% at 2 years. We showed a significant decrease in global seizure count per month one year after DBS (68.1%; P=0.013) leading to an overall improvement in quality of life. No major adverse effect was recorded during the follow-up. ANT DBS showed a prominent significant effect with a decrease of the number of generalized seizures.

CONCLUSION

We aimed at a better ANT/lead collimation using a vertical transventricular approach under microendoscopic monitoring. This technique permitted to demonstrate the safety and the accuracy of the procedure.

Dentate nucleus as target for deep brain stimulation in dystono-dyskinetic syndromes

PURPOSE

To discuss the potential of deep brain stimulation (DBS) of the dentate nucleus as a treatment for dystono-dyskinetic syndromes.

METHODS

An extensive literature review covered the anatomy and physiology of the dentate nucleus and the experimental evidence for its involvement in the pathophysiology of dystonia and dyskinesia.

RESULTS

Evidence from animal models and from functional imaging in humans is strongly in favor of involvement of the dentate nucleus in dystono-dyskinetic syndromes. Results from previous surgical series of dentate nucleus stimulation were promising but precise description of movement disorders being treated were lacking and outcome measures were generally not well defined.

CONCLUSIONS

In the light of new evidence regarding the involvement of the dentate nucleus in dystono-dyskinetic syndromes, we present a review of the current literature and discuss why the question of dentate nucleus stimulation deserves to be revisited.

Long-term follow-up of pallidal Deep Brain Stimulation in teenagers with refractory Tourette syndrome and comorbid psychiatric disorders: About three cases

OBJECTIVES

Tourette syndrome (TS) is a complex neuropsychiatric disorder associated with comorbid psychiatric disorders. Peak of tic severity typically occurs in early adolescence and impacts quality of life. Since 1999, promising therapeutic effects of Deep Brain Stimulation (DBS) have been reported in tic reduction for adults with refractory TS. The aim of the study was to assess the long-term risk-benefit ratio of pallidal DBS for young patients with refractory TS and severe comorbid psychiatric disorders.

METHODS

We retrospectively assessed the long-term clinical outcomes of three adolescents who underwent pallidal DBS for the treatment of refractory TS.

RESULTS

The mean duration of follow-up was 52 months in our case series. We observed that motor tics decreased with posteroventral GPi DBS in all patients, without reaching a continuous significance over the long-term follow-up. Self-reported social inclusion was globally improved, despite lack of efficacy of DBS on comorbid conditions.

CONCLUSIONS

These findings suggest a long-term therapeutic benefit of early DBS intervention for highly socially impaired young patients suffering from intractable TS with severe comorbid psychiatric conditions. Further studies are needed to determine the most effective targets of DBS on both tics and comorbid psychiatric profile of TS.

A Case of Vertebrovertebral Arteriovenous Fistula Presenting with Subarachnoid Haemorrhage

A rare paediatric case of vertebrovertebral arteriovenous fistula presented with a subarachnoid haemorrhage.

A 12 year-old boy, who fell on his back at school, presented with a one week history of headache, vomiting, and double vision. Computed tomography (CT) scan revealed subarachnoid haemorrhage.

Magnetic resonance imaging (MRI) demonstrated a tortuous vessel on the anterior surface of the spinal cord. Selective angiography showed an arteriovenous fistula of the left vertebral artery at the level of C1.

The venous drainage of the fistula refluxed into the medullary vein at the level of C6-7, and drained upwards into the posterior fossa veins. An endovascular detachable balloon technique was employed and complete occlusion of the fistula was achieved.

Psychiatric comorbidity in temporal DNET and improvement after surgery

BACKGROUND

"Alien tissue" may be responsible for a higher frequency of psychiatric disorders in patients with temporal lobe epilepsy (TLE). Also, ganglioglioma and dysembryoplastic neuroepithelial tumors (DNET) could represent a risk-factor for the development of post-surgical psychoses. Classically, severe psychiatric disorders contra-indicate epilepsy surgery.

OBJECTIVES

Assessment of inter-ictal psychiatric disorders in 10 consecutive patients with temporal DNET, before and after epilepsy surgery with a minimum of a 2-year follow-up evaluation.

METHODS

DNETs were confirmed on histological examination. Psychiatric disorders were classified according to the DSM-IV-TR.

RESULTS

Five patients presented inter-ictal psychiatric disorders with, according to the DSM-IV-TR, undifferentiated schizophrenia (one case), "borderline" personality (two cases), intermittent explosive disorder with slight mental retardation (one case), and personality disorders not otherwise specified but with some traits of dependent personality and with mythomania (one case). The condition of these five patients dramatically improved after surgery. No psychiatric behavior or "de novo" psychosis was observed after surgery in any of the patients.

CONCLUSION

The prevalence of inter-ictal psychiatric disorders appears to be high in epileptic patients with a temporal lobe DNET primarily in relation to personality and behavioral problems with some degree of impulsivity and verbal aggressiveness. The improvements after surgery suggest that this therapy could be performed in these patients and severe psychiatric disorders do not contra-indicate this procedure.

Chiari malformation and sleep related breathing disorders

OBJECTIVE

To estimate the frequency, mechanisms and predictive factors of sleep apnoea syndrome (SAS) in a large group of children and adults with type I (CMI) and II (CMII) Chiari malformation (CM).

BACKGROUND

The anatomical and functional integrity of both respiratory circuits and lower cranial nerves controlling the upper airway is necessary for breathing control during sleep. These latter structures may be altered in CM, and a few investigations have reported CM related sleep disordered breathing.

METHODS

Forty-six consecutive unrelated patients with CM (40 CMI, six CMII), of which 20 were children (eight males) and 26 were adults (12 males), underwent physical, neurological and oto-rhino-laryngoscopic examination, MRI and polysomnography.

RESULTS

SAS was present in 31 (67.4%) of the patients with CM (70% of CMI, 50% of CMII, including mainly children). Sixty per cent of children with CM exhibited SAS, including 35% with obstructive (OSAS) and 25% with central (CSAS) sleep apnoea syndrome. SAS was observed in 73% of CM adults (57.7% OSAS, 15.4% CSAS). Severe SAS was found in 23% of CM adults. Multiple regression analysis revealed that age, type II Chiari and vocal cord paralysis predicted the central apnoea index.

CONCLUSION

SAS is highly prevalent in all age groups of patients suffering from CM. CSAS, a rare condition in the general population, was common among the patients with CM in our study. Sleep disordered breathing associated with CM may explain the high frequency of respiratory failures observed during curative surgery of CM. Our results suggest that SAS should be systematically screened for in patients with CM, especially before surgery.

[Neurosurgical treatment in childhood dystonias and dyskinesias]

AIM

To present the post-surgery clinical results of deep brain stimulation of the internal globus pallidus (GPi) in a group of paediatric patients with primary and secondary dystonic-dyskinetic syndrome.

PATIENTS AND METHODS

Between November 1996 and May 2006, 121 patients were submitted to interventions with bilateral deep brain stimulation of the GPi, 58 of whom were children (age range: 5-16 years); 35 were cases of primary dystonia, of which 17 were carriers of the DYT1 mutation and 10 were not. A further 8 cases were myoclonic dystonias, 3 of whom presented the DYT11 mutation. With regard to the secondary dystonias, 4 were carriers of PKAN (pantothenate kinase-associated neurodegeneration) syndrome and 9 were cases of post-anoxic encephalopathies.

RESULTS

Percentage improvements were as follows: in the case of DYT1+ primary dystonias, 80% at one year maintained at 3 years; in cases of DYT1-, 70% at one year maintained at 3 years, and in the myoclonic dystonias, 50% at one year and 85% at 3 years. In the group of patients with secondary dystonias due to post-anoxic encephalopathies, we found an improvement of 30% at one year and 40% at 3 years; in the group with PKAN syndrome, the figures were 60% at one year and 50% at two years.

CONCLUSIONS

Treatment involving bilateral deep brain stimulation of the GPi nuclei in childhood cases of generalised dystonias is highly effective, the best prognoses being those offered by the group with primary dystonias and especially those related to the DYT1 mutation. Treatment also proved to be effective in the case of secondary dystonias, although with lower degrees of improvement.

The diverse phenotype and genotype of pantothenate kinase-associated neurodegeneration

Pantothenate kinase-associated neurodegeneration (PKAN) is a rare autosomal-recessive disorder caused by mutations in the PANK2 gene. The authors report clinical and genetic findings of 16 patients with PKAN. The authors identified 12 mutations in the PANK2 gene, five of which were new. Only nine patients could be classified as classic or atypical PKAN, and intermediate phenotypes are described. Two patients presented with motor tics and obsessive-compulsive behavior suggestive of Tourette syndrome.

[Acutely ruptured intracranial aneurysms treated with GDC coils. Results from a single center over a period of 5 years]

PURPOSE

We prospectively reviewed the clinical results of acutely ruptured cerebral aneurysms treated with GDC over a 5 year period, in order to characterize death and dependency factors.

METHODS

Between 1997 and 2002, 229 patients (254 aneurysms treated, 140 females, 89 males; mean age: 51 years) with aneurysmal subarachnoid hemorrhage were treated with GDC (Boston Scientific Neurovascular, Fremont, CA) once the anatomical conditions of feasibility had been achieved. Over 90% of the aneurysms treated (mean size: 5,8 mm) were located in the anterior circulation. The anterior communicating artery complex (87 cases), the posterior aspect of the internal carotid artery (65 cases), and the middle cerebral artery (49 cases) were most commonly treated.

RESULTS

At the end of the initial hospitalization period, 14 patients (6.1%) died. Major procedural complications were associated with perforation of the aneurysmal sac in 9 patients (3.9%), thromboembolic events in 10 patients (4.3%) which resulted in 2 deaths (0.8%) and permanent neurologic morbidity in 7 patients (3%). The univariate analysis demonstrated no correlation between death and time-to-treatment, the topography of the aneurysm, or the occurrence of treatment related complications. The results of the logistical regression model demonstrated that the clinical score upon entry, and the occurrence of delayed ischemia were the only independent factors correlated with patient death. The prognostic factors affecting the degree of sequellae identified by the logistical regression model were the clinical score upon admission, age, treatment related complications, and pulmonary complications.

CONCLUSIONS

Endovascular treatment of ruptured anterior circulation aneurysms with GDC, including MCA aneurysms, is associated with low morbidity and allows good overall outcomes in patients with subarachnoid hemorrhage. A better understanding of dependency factors associated with endovascular coiling will foster further technical advances in order to improve the treatment of small and medium sized ruptured aneurysms.

Electrophysiological characteristics of limbic and motor globus pallidus internus (GPI) neurons in two cases of Lesch–Nyhan syndrome

OBJECTIVE

Lesch-Nyhan syndrome is a rare and debilitating condition characterized by dystonia and self-mutilating behavior. In order to shed light on the pathophysiology of dystonia, we report the pallidal electrophysiological activity recorded in two patients during deep brain stimulation surgery (DBS).

METHODS

Microrecordings were performed on 162 neurons along four tracks aimed at the right and left anterior (limbic) and posterior (motor) globus pallidus internus (GPI).

RESULTS

Regardless of the anesthetic agent used (propofol or sevoflurane), both patients showed similar neurons firing rates in the four regions studied, namely the limbic and motor portions of the globus pallidus externus (GPE) or GPI. In both patients, firing rates were similar in the GPE (12.2+/-1.8 Hz, N=38) and GPI (13.2+/-1.0 Hz, N=83) portions of the limbic track, while the motor GPE fired at a higher frequency (23.8+/-2.7 Hz, N=18) than the motor GPI (12.5+/-1.4 Hz, N=23).

CONCLUSIONS

These results demonstrate that light propofol or sevoflurane anesthesia influences pallidal activity in a similar way. Electrophysiological recordings suggest that Lesch-Nyhan syndrome might be characterized by analogous firing frequencies in the limbic GPE and GPI while motor GPE would tend to fire at higher rate than the motor GPI. It is therefore tempting to suggest that the symptoms that are observed in Lesch-Nyhan syndrome might result from motor GPI inhibition.

SIGNIFICANCE

This observation may confirm the Albin and Delong's model of the basal nuclei in hypokinetic and hyperkinetic disorders.

Lamotrigine associated with exacerbation or de novo myoclonus in idiopathic generalized epilepsies

Five patients with idiopathic generalized epilepsies (IGE) treated with lamotrigine (LTG) experienced exacerbation or de novo appearance of myoclonic jerks (MJ). In three patients, LTG exacerbated MJ in a dose-dependent manner with early aggravation during titration. MJ disappeared when LTG dose was decreased by 25 to 50%. In two patients, LTG exacerbated MJ in a delayed but more severe manner, with myoclonic status that only ceased after LTG withdrawal.

[Kinematic evaluation of dystonic syndromes in patients treated with deep brain stimulation]

INTRODUCTION

Quantification of motor functions of patients with dystonic syndromes treated by chronic high frequency stimulation of the internal globulus pallidus is a challenge.

OBJECTIVE

Through a series of clinical examples this paper shows that kinematic analysis of movements in dystonic syndromes treated by deep brain stimulation (DBS) is a complement to clinical evaluation. In addition, it provides valuable information for early detection of improvement or impairment of movements associated with modifications of stimulation parameters.

METHOD

Thirteen dystonic patients and eleven reference subjects completed three tests (i.e., rest: lying supine; posture: standing with arms held in front (at shoulder height); and alternative movements: bimanual finger-to-nose test). These tests were recorded with an electromagnetic system quantifying movement kinematics (position) in three-dimensional space.

RESULTS

From the recorded data, several indices were developed and provided a quantitative evaluation of movements during each test. In addition, a clinical evaluation (BMFDRS) was also completed. No correlation between clinical and kinematic evaluations was found.

CONCLUSION

It is shown that kinematic analysis is a useful complement of clinical evaluation and can assist clinicians in monitoring the evolution of movements in dystonic patients treated by DBS in a simple, reliable and valid fashion.

Syndrome de Parry-Romberg et épilepsie

INTRODUCTION

Parry-Romberg's syndrome or progressive facial hemiatrophy is a rare disorder of unknown etiology which may be accompanied by neurological complications, frequently epilepsy, usually focal refractory epilepsy. The associated brain lesions are located on the same side as the half face atrophy and may progress.

OBSERVATION

We report the cases of two patients with Parry-Romberg's syndrome and epilepsy. Neurosurgery was performed in one patient, enabling a histological study.

CONCLUSION

The link between Parry-Romberg's syndrome and epilepsy is discussed and the neurodevelopmental theory with vascular dysgenesis is suggested.

Mutations within the programmed cell death 10 gene cause cerebral cavernous malformations

Cerebral cavernous malformations (CCMs) are hamartomatous vascular malformations characterized by abnormally enlarged capillary cavities without intervening brain parenchyma. They cause seizures and cerebral hemorrhages, which can result in focal neurological deficits. Three CCM loci have been mapped, and loss-of-function mutations were identified in the KRIT1 (CCM1) and MGC4607 (CCM2) genes. We report herein the identification of PDCD10 (programmed cell death 10) as the CCM3 gene. The CCM3 locus has been previously mapped to 3q26-27 within a 22-cM interval that is bracketed by D3S1763 and D3S1262. We hypothesized that genomic deletions might occur at the CCM3 locus, as reported previously to occur at the CCM2 locus. Through high-density microsatellite genotyping of 20 families, we identified, in one family, null alleles that resulted from a deletion within a 4-Mb interval flanked by markers D3S3668 and D3S1614. This de novo deletion encompassed D3S1763, which strongly suggests that the CCM3 gene lies within a 970-kb region bracketed by D3S1763 and D3S1614. Six additional distinct deleterious mutations within PDCD10, one of the five known genes mapped within this interval, were identified in seven families. Three of these mutations were nonsense mutations, and two led to an aberrant splicing of exon 9, with a frameshift and a longer open reading frame within exon 10. The last of the six mutations led to an aberrant splicing of exon 5, without frameshift. Three of these mutations occurred de novo. All of them cosegregated with the disease in the families and were not observed in 200 control chromosomes. PDCD10, also called "TFAR15," had been initially identified through a screening for genes differentially expressed during the induction of apoptosis in the TF-1 premyeloid cell line. It is highly conserved in both vertebrates and invertebrates. Its implication in cerebral cavernous malformations strongly suggests that it is a new player in vascular morphogenesis and/or remodeling.

Accelerometric measurement of involuntary movements during pallidal deep brain stimulation of patients with generalized dystonia

Accelerometric activity during rest and posture was quantified in the upper dominant limb of 14 patients with primary or secondary dystonia and five healthy control subjects. Data were recorded before and after bilateral implantation of the stimulating electrodes in the Globus Pallidus internus. Clinical evaluation was based on the Burke-Marsden-Fahn's Dystonia Rating Scale (BMFDRS). For the patient group, I(t), the integral (i.e. area) of the acceleration power spectrum over the total frequency range (0.6-16 Hz) decreased as the clinical state of the patients improved following deep brain stimulation (p < 0.01) during rest and posture. Ten days after surgery, there were no I(t) differences between control subjects and patients (p > 0.05). A significant correlation was found between the global BMFDRS scores and I(t) for rest (p < 0.01) but not for posture. No significant correlation was found between I(t) and a partial BMFDRS score for the right arm for rest or posture. The integral I(t) provides a valid indicator of the motor activity generated by the arm of the patient but further analyses are needed to monitor patients' progress not only during their hospitalization but also after they are released from the hospital, and to understand why this measure does not correlate with partial BMFDRS scores.

[Percutaneous sacral thermorhizotomy to treat equinism of spastic cerebral palsy children]

We propose to evaluate the effect of sacral percutaneous thermorhizotomy on cerebral palsy children. A prospective study including 29 children followed by a multidisciplinary team was conducted from 1990 to 2000. A thermal radiofrequency lesion of the first sacral root was obtained by percutaneous puncture of the posterior intervertebral foramen with evaluation by stimulation of the best motor response for the minimal threshold (<0.5 volts). The efficacy of the lesion was evaluated by testing and modification of the stimulation threshold obtained (x 2). The results on spasticity was evaluated using the Held score and the functional effect on walking, and classified as "good" (9 cases), "efficacy" (6 cases) and "nil" (4 cases). Indications of the procedure are discussed during the walking acquisition period and growing period of the cerebral palsy child.

Treatment of dystonic syndromes by chronic electrical stimulation of the internal globus pallidus

AIM

Dystonia is a medically intractable condition causing twisting or myoclonic movements and abnormal postures. There is an important heterogeneity among etiologies of dystonia. The electrical stimulation of the globus pallidus has been used successfully in primary generalized dystonia. The aim of this study was to examine the long-term efficacy and safety of deep brain stimulation (DBS) in the treatment of primary and secondary generalized dystonia in children and adults.

METHODS

Fifty-three patients were included. Electrodes were bilaterally implanted under stereotactic guidance and connected to neurostimulators, subcutaneously inserted. Efficacy was evaluated by comparing scores on the clinical and functional Burke-Marsden-Fahn dystonia rating scales (BMFDRS) before and after implantation. Patients were divided into 3 groups: group 1 comprised 15 patients with DYT1 dystonia; group 2, 17 patients with dystonia of unknown etiology and group 3, 21 patients with secondary dystonia. The mean follow-up was 26.6+/-12.3 months for primary dystonia and 23.1+/-11.8 for secondary dystonia.

RESULTS

After 1 year, the improvement of the clinical score is 71% in group 1, 74% in group 2 and 31% in group 3. The functional score was improved by 63% in group 1, 49% in group 2 and 7% in group 3. We did not find any significant difference between children and adults. In secondary dystonia, efficacy of the stimulation is more limited. The efficacy of the stimulation improved with time for the 3 groups. COMCLUSION: Electrical stimulation of the internal globus pallidus proved to be an effective treatment for generalized dystonia and should be considered as first-line therapy.

[The varied etiologies of childhood-onset dystonia]

Dystonia is not uncommon in childhood, and identification of its etiology is an ultimate aim in the clinical evaluation of dystonia. Advances in neuroimaging, recent identification of gene or loci implicated in dystonic syndromes, and characterisation of new pathological entities (creatine deficiency, biotin-responsive basal ganglia disease) enlarge our understanding of childhood dystonia, and expend its diagnosis spectrum. Awareness of the diverse etiologic categories of childhood-onset dystonia is necessary to accurate diagnosis approach. Clinical examination and cerebral magnetic resonance imaging are the keys of this diagnosis approach. Primary dystonia is defined as syndromes in which dystonia is the sole phenotypic manifestation (especially no cognitive deterioration is observed, and brain MRI is normal); DYT1 dystonia, in which the abnormal gene is located on chromosome 9, is the most frequent childhood-onset primary dystonia; progressive generalisation of the abnormal movements occur in 70p.cent of the patients. Dopa - Responsive Dystonia are characterized by marked diurnal fluctuations of the dystonic symptoms and by their marked and sustained response to dopaminergic therapy; associated parkinsonian signs are usually observed later in the course of the disease. Clinical presentation of DRD might be atypical (mimicking cerebral palsy or isolated limb pain without diurnal fluctuation). DRD is rare, but a trial of L-dopa should be performed on all patients with childhood-onset dystonia, lasting at least one month. Secondary dystonias or heredodegenerative diseases are the most frequent etiology of childhood-onset dystonic syndromes. Among a huge range of heredodegenerative disease, those that are amenable to a specific treatment, such as Wilson's disease or creatine deficiency, should be particularly investigated. The main objective of investigation of dystonia is to identify secondary dystonias or heredodegenerative diseases. Further investigations will be performed according to the clinical characteristics of the dystonia, to the presence of associated neurological or extraneurological symptoms, and according to brain imaging; this approach must be discussed for each single patient. The aim of the diagnosis strategy is the rapid identification of the etiology of dystonia which will lead to accurate treatment and pertinent genetic counselling.

[Localizing and prognosis value of 99Tcm-ECD spect in patients with refractory temporal lobe epilepsies]

Interictal and ictal 99Tcm ECD-SPECT were retrospectively studied in 46 patients with refractory temporal lobe epilepsy. Forty two of these patients underwent an anterior temporal lobectomy with amygdalo-hippocampectomy or a cortical resection. SPECT findings as indicator of localization for the epileptogenic zone (EZ) and surgical prognosis were validated by comparison with other investigations including video-EEG monitoring with surface electrodes in all the patients, intracranial electrodes in 18 patients and the results of post-surgery outcome. Reliability of SPECT for localizing the epileptogenic zone (EZ) was found for mesial temporal epilepsy (28 patients) and the presumed bilateral temporal epilepsies (7 patients). In these latter cases, ECD-SPECT findings may serve to replace invasive methods with use of intracranial electrodes. SPECTs were unreliable when EZ was undetermined whether mesial or lateral by other non invasive investigations. Unilateral mesial temporal hyperperfusion associated with hypoperfusion of contralateral mesial structures evidenced by ictal SPECTs appear to be preoperative criteria for a successful outcome after surgery.

Appearance of new lesions in two nonfamilial cerebral cavernoma patients

Cavernomas are vascular malformations mostly observed in the central nervous system. They occur in sporadic and familial forms. Familial forms are characterized by the presence of multiple lesions, an autosomal dominant pattern of inheritance and possible de novo lesions. We report two sporadic cases whose follow-up showed the appearance of new lesions.

Magnetic resonance imaging stereotactic target localization for deep brain stimulation in dystonic children

OBJECT

The actual distortion present in a given series of magnetic resonance (MR) images is difficult to establish. The purpose of this study was to validate an MR imaging-based methodology for stereotactic targeting of the internal globus pallidus during electrode implantation in children in whom general anesthesia had been induced.

METHODS

Twelve children (mean follow up 1 year) suffering from generalized dystonia were treated with deep brain stimulation by using a head frame and MR imaging. To analyze the influence of distortions at every step of the procedure, the geometrical characteristics of the frame were first controlled using the localizer as a phantom. Then pre- and postoperative coordinates of fixed anatomical landmarks and electrode positions, both determined with the head frame in place, were statistically compared. No significant difference was observed between theoretical and measured dimensions of the localizer (Student's t-test, ¿t¿ > 2.2 for 12 patients) in the x, y, and z directions. No significant differences were observed (Wilcoxon paired-sample test) between the following: 1) pre- and postoperative coordinates of the anterior commissure (AC) (deltax = 0.3+/-0.29 mm and deltay = 0.34+/-0.32 mm) and posterior commissure (PC) (deltax = 0.15+/-0.18 mm and deltay = 0.34+/-0.25 mm); 2) pre- and postoperative AC-PC distance (deltaL = 0.33+/-0.22 mm); and 3) preoperative target and final electrode position coordinates (deltax = 0.24+/-0.22 mm; deltay = 0.19+/-0.16 mm).

CONCLUSIONS

In the authors' center, MR imaging distortions did not induce detectable errors during stereotactic surgery in dystonic children. Target localization and electrode implantation could be achieved using MR imaging alone after induction of general anesthesia. The remarkable postoperative improvement in these patients confirmed the accuracy of the procedure (Burke-Marsden-Fahn Dystonia Rating Scale score delta = -83.8%).

Sleep influence on seizures and epilepsy effects on sleep in partial frontal and temporal lobe epilepsies

OBJECTIVES

A reciprocal effect is observed between sleep and epilepsy. Sleep effect on epilepsy is protective and facilitating. Reciprocally epilepsy alters sleep organization and microarchitecture. This interelationship is well established for some epilepsies but remains undefined for cryptogenic and symptomatic frontal and temporal lobe epilepsies. In order to research sleep influence on seizures and epilepsy effects on sleep we carried out two studies in patients with cryptogenic/symptomatic frontal or temporal lobe epilepsies.

METHODS

The occurrence of seizures in relation to the state of alertness was analyzed in patients with (1) mesial temporal and frontal lobe epilepsy, and (2) in patients with mesio-lateral temporal and mesial temporal lobe epilepsy in several conditions. Sleep analysis (organization and microarchitecture) was realized.

RESULTS

We found: (1) a precise relationship between sleep and seizures in frontal lobe epilepsy (FLE); (2) a precise relationship between wakefulness and seizures in temporal lobe epilepsy (TLE); (3) sleep organization was normal in FLE and altered in TLE; (4) alterations of sleep microarchitecture in FLE and TLE.

CONCLUSIONS

Seizure occurrence was mainly in relation to sleep for FLE and to wakefulness for TLE. Sleep organization appeared more altered for TLE than FLE. These results allow practical applications to localize and study FLE and TLE.

Treatment of DYT1-generalised dystonia by stimulation of the internal globus pallidus

In seven selected patients with dystonia musculorum deformans-1 generalised dystonia (DYT1), continuous bilateral stimulation of the globus pallidus internus was associated with substantial improvement of dystonia and functional disability.

Treatment of early-onset dystonia: update and a new perspective

Dystonia is a rare disease of childhood, often leading to devastating functional impairment. Medical treatment is reviewed, although its efficacy is often limited. Recent advances in functional neurosurgery have opened up a new field in the management of dystonic patients, and the results of deep brain stimulation are given particular emphasis.

[Treatment of early-onset generalized dystonia by chronic bilateral stimulation of the internal globus pallidus. Apropos of a case]

Dystonia musculorum deformans is an inherited severe disease, with a wide clinical polymorphism. The most severe clinical forms with early onset carry a high risk of life-threatening complications. In the absence of any efficient medical treatment, bilateral pallidotomy has previously been reported to be of value in the management of this disease. We report the first clinical case of a severe early-onset generalized dystonia dramatically improved by a bilateral stimulation of the internal globus pallidus. In November 1996, we proposed this neurosurgical procedure for a 8-year-old girl, who had suffered since the age of 3 from severe generalized dystonia, and who progressively became totally dependent and bedridden. She had been under sedation and permanent controlled respiratory assistance for the last two months. The etiology of the disease remained unknown (the DYT1 mutation was absent). Under general anesthesia, we bilaterally implanted a four-contacts electrode in the internal globus pallidus, using the Leksell's stereotactic frame and a 1.5 tesla MRI control. A dramatic improvement was noted 6 weeks later and led us to connect the two electrodes to neurostimulators inserted under the abdominal skin.

[Effect of awakening and sleep deprivation in triggering idiopathic generalized epilepsy]

The facilitating effect of awakening and sleep deprivation on seizure production and EEG abnormalities is characteristic of idiopathic generalized epilepsies (IGE). This effect is particularly patent in awakening epilepsy. Paroxysmal events occurring in non-REM sleep, related to spindle production during transitional periods or awakening are characteristic of IGE. Because IGEs are particularly sensitive to sleep, sleep deprivation, and awakening, the association of these three conditions is particularly helpful in exploration protocols, especially when no wakefulness abnormalities are seen on the EEG. These observations in IGE suggest a dysfunction of awakening control systems. Awakening epilepsies may be differentiated from sleep-induced seizures observed in other IGE and in partial epilepsies.

The relationship between sleep and epilepsy in frontal and temporal lobe epilepsies: practical and physiopathologic considerations

PURPOSE

The influence of sleep on the incidence of seizures and the reciprocal effects of epilepsy on sleep were analyzed in 30 patients with intractable partial seizures, all candidates for surgery.

METHODS

The patients were classified into two groups of 15 patients according to the documented site of the epileptogenic zone: frontal lobe epilepsy (FLE) and medial temporal lobe epilepsy (TLE). Frequency and waking-sleep distribution of seizures were evaluated by continuous video-EEG monitoring for 5 days, under defined antiepileptic drug (AED), sleep, and sleep deprivation regimens. Sleep organization was analyzed by polysomnography prior to the presurgical protocol.

RESULTS

Significant differences were found between the two groups in sleeping-waking distribution of seizures under varied conditions, and in the quality of sleep organization. In FLE patients, seizures most often occurred during sleep, although sleep organization was normal. In TLE patients, most seizures occurred while patients were awake, and sleep organization was characterized by a low efficiency index. The difference in seizure distribution between FLE and TLE persisted under all conditions investigated, i.e., after AED discontinuation and sleep deprivation.

CONCLUSIONS

Sleep recording may be useful for diagnosis of FLE, and monitoring after sleep deprivation for that of TLE. We speculate that sleep-related seizures in FLE may depend on interaction between frontal lobe areas with the thalamus cortical synchronization system and the acetylcholine regulatory system of waking.

[Ectopic intraspinal extradural anaplastic ependymoma in an infant]

BACKGROUND

Ependymomas represent about 10% of the spinal tumors in children. Some of them may be unusually located.

CASE REPORT

A 10-month-old boy was admitted for an abdominal mass syndrome with dehydration asthenia and acute bladder dysfunction. A few hours later, he developed a flaccid paraplegia. Ultrasonic and magnetic resonance spinal imaging showed a giant intraspinal tumor extending from T9 to IA level, posteriorly located to the dural compartment, widening the spinal cord. Ultrasonography also showed right ureterohydronephrosis due to the neurological bladder dysfunction. A conservative laminotomy-laminoplasty was performed in emergency. Total removal of the tumor that was attached to the right dorsal root was achieved extradurally, requiring resection of the proximal part of the root. Histological features were typical of malignant ependymoma. Chemotherapy was initiated 2 weeks later. The severe renal destruction and the persistent bladder dysfunction led to a heminephrectomy and a cystostomy, 3 weeks later. The neurological recovery was only partial with a follow-up of 18 months.

CONCLUSION

Ectopic intraspinal extradural localization of ependymomas is rare and their development from a nerve root is exceptional.

Total endovascular occlusion of a giant direct arteriovenous fistula in the posterior fossa in a case of Rendu-Osler-Weber disease

We report a case of giant single-hole direct arteriovenous fistula (AVF) located in the posterior fossa of a child with Rendu-Osler-Weber disease (ROW). There is neither a clinical nor an angioarchitectural difference between AVFs associated with ROW and sporadic AVFs, but ROW should be suspected in children with multifocal pial AVFs. Transarterial embolization was performed to obliterate the AVF in a unique procedure using simultaneous bifemoral catheterization. At follow up 4 years later, the clinical examination was normal. Control MR scans and angiography showed the total occlusion of the fistula, permanent thrombosis of the venous pouch, and disappearance of the abnormal venous drainage. In this case, the endovascular procedure was available and we estimated that it represented a lesser risk than the surgical approach (risk of hemorrhage and risk of thrombosis involving the feeding arteries and the brain stem venous drainage). Furthermore, it avoids craniotomy and reduces the duration of hospitalization.

Expression of the tumor over-expressed ch-TOG gene in human and baboon brain

We recently reported on the over-expression of a new gene, colonic and hepatic tumor over-expressed gene (ch-TOG) in human hepatomas and colonic tumors. Although ubiquitous in healthy tissues, its expression was found to be particularly elevated in the brain. In the present study, we demonstrate the expression of ch-TOG mRNA in human brain tumors as well as in numerous areas of healthy human and baboon brain. This expression was analyzed by reverse transcription-polymerase chain reaction (RT-PCR), Northern blotting, RNAse protection assays and in situ hybridization. An interesting feature is the demonstration that, although ubiquitous in the brain, the ch-TOG gene is highly expressed in the Purkinje cell bodies of the human cerebellum.

Monitoring sodium methohexital distribution with [99mTc]HMPAO with single photon emission computed tomography during Wada test

Twenty-five consecutive patients being considered for surgery for intractable epilepsy had intracarotid sodium methohexital procedures (ISM) as part of their evaluation. The lipophilic brain SPECT agent, [99mTc]hexamethylpropylene aminoxime (HMPAO), was administered intravenously during the procedure to determine the intracerebral distribution of methohexital. The validity of the ISM depends on consistent delivery of the anesthetizing agent to one hemisphere, including the mesial structures of the temporal lobe. To prevent postoperative language and memory deficits, correct interpretation of the test results supposes a reliable knowledge of which regions of the brain have been anesthetized. Currently, no absolute criteria allow determination of the level and topographical extent of the anesthesia. We compared results of HMPAO-SPECT with clinical and EEG video-monitoring data and with results of digital subtraction angiography (DSA) performed during the test. In all patients, the effect of SM was ipsilateral cerebral hypoperfusion on SPECT and crossed cerebellar diaschisis. The distribution of HMPAO varied from patient to patient. The delivery of SM to mesial temporal lobe structures was not constant. Using nonparametric tests, we demonstrated a statistically significant relationship between hypoperfusion on SPECT and duration of hemiplegia but not with the duration of aphasia. Hypoperfusion on SPECT was also related to the onset and duration of drug-induced delta activity on EEG. SPECT showed a statistically different distribution of SM in the brain from that predicted with DSA. We present our experience with HMPAO-SPECT use for mapping the distribution of methohexital's effects during the ISM (Wada test). We confirm the results of previous studies that SPECT assessment may be an excellent way of determining the distribution of barbiturate during the examination. It increases confidence in interpreting results of speech and memory testing by detecting either contralateral diffusion of the drug due to crossflow between hemispheres or insufficient quantitative delivery to the homolateral hemisphere.

Pial arteriovenous fistula in children as presenting manifestation of Rendu-Osler-Weber disease

We present four cases of pial arteriovenous fistula (AVF) in children as the presenting manifestation of Rendu-Osler-Weber disease (ROW). The common clinical manifestations of ROW in adults, such as skin telangiectasia and mucosal haemorrhagic complications, seldom occur in children, since telangiectases develop with age. Pial AVF in ROW also conform to the usual age incidence and are therefore present in childhood. Of the four children in this series, three had multiple AVF. Two presented with central nervous system haemorrhage, one with seizures and the other with progressive neurological deficit. There were no clinical or angioarchitectural differences between the AVF associated with ROW and sporadic AVF. The diagnosis was based in all cases on the family history. Transarterial embolisation to obliterate the AVF was carried out in all patients. One patient had early rebleeding after partial embolisation of the AVF, with a fatal outcome. Three patients were cured and one asymptomatic in long-term follow up. No exhaustive search was conducted for multiorgan telangiectases, since there is no indication for treatment of asymptomatic telangiectasia in ROW. No pulmonary fistulae were found. ROW should be suspected in children with multiple pial AVF; they may be the only manifestation of the disease, since epistaxis and telangiectasia are unusual in early life.

Comparison and spacial correlation of interictal HMPAO-SPECT and FDG-PET in intractable temporal lobe epilepsy

The respective contribution of interictal HMPAO-SPECT and FDG-PET to the imaging of the epileptogenic zone in intractable temporal lobe epilepsy is not known. Ten consecutive patients with drug resistant focal epilepsy of temporal lobe origin were studied with prolonged noninvasive video-EEG monitoring, magnetic resonance imaging, interictal FDG-PET and HMPAO-SPECT. Five patients demonstrated unitemporal and 5 patients bitemporal interictal and/or ictal EEG epileptiform abnormalities. We developed a 3-dimensional semiquantitative method for interpretation and comparison of FDG-PET and HMPAO-SPECT using a 15-compartment model of the temporal lobe. In all 5 patients with unilateral epileptogenicity, interictal hypometabolism and hypoperfusion were recorded on the side of the EEG abnormalities without discrepancy between PET and SPECT. The severity and the extent of focal abnormalities were consistently greater on PET than on SPECT, in agreement with previously well documented better 'sensitivity' of PET. Among the 5 patients with bitemporal epileptogenicity, results of SPECT and PET were convergent in only 2 cases. In this group, SPECT abnormalities appeared more profound but either SPECT or PET were not constantly correlated with the side of predominant EEG epileptogenicity. Abnormalities on PET and SPECT were more frequently limited to mesiobasal structures among cases with unilateral epileptogenicity and tended to involve neocortical structures in bitemporal cases. We conclude that interictal FDG-PET and HMPAO-SPECT provide the same type of information on the side of the epileptogenic zone in cases with clearly unilateral epileptogenicity, with abnormalities more intense and more extensive on PET.(ABSTRACT TRUNCATED AT 250 WORDS)

[Immunologic diagnosis of the cerebrospinal fluid and serum in developing brain cysticercosis]

ELISA detection of specific antibodies in the serum (IgG) and cerebrospinal fluid (IgG, IgM and IgA) was evaluated in 28 patients. Diagnosis of cerebral cysticercosis and evaluation of disease activity was based on CT scan findings. Specific IgG antibodies were found in the serum in 83.3% of patients with active disease and 10% of those with inactive disease. Cerebrospinal fluid tests evidenced specific antibodies in all patients with active disease and none of the patients with inactive disease. The specific CSF antibodies were IgG (94.4%), IgM (66.6%) or IgA (66.6%). Antibody titers were significantly higher in patients with an intraventricular vesicle or cyst.

[Acute polyradiculoneuritis after intravenous injection of heroin, HIV seropositivity disclosed 3 years later]

An acute polyradiculoneuritis with tetraplegia and respiratory failure was observed in a 27 year-old heroin addict 3 hours after an intravenous injection of heroin. Full recovery was obtained after respiratory assistance and plasma exchanges. The biological and morphological changes (sural nerve biopsy) suggested an immune mediated mechanism. Three years after the recovery, the patient was tested for HIV antibody and was seropositive. The role of HIV infection and of the injection of heroin are discussed.