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J Chazal

Publications and source records attributed to J Chazal.

At least 19 recordsLinked to original sources
PubMed1999

Direct stereotactic MRI location in the globus pallidus for chronic stimulation in Parkinson's disease.

We evaluated the direct location in the globus pallidus (GP) under stereotactic MRI (sMRI) guidance in five parkinsonians treated with chronic deep brain stimulation (four bilaterally). The sMRI consisted of three orthogonal (horizontal, frontal, sagittal) sets of images obtained with a stereotactic frame and its localiser. The sMRI was coupled with ventriculography to compare the location with the classic indirect method based on commissural landmarks. The target was defined on T2-weighted slices in the anterior part of the medial GP, at the vertex of the nucleus. It was reached via one track with a semi-micro-electrode and step by step high frequency stimulation, then replaced by a quadripolar electrode once we located the site enabling the optimal clinical improvement. Stereotactic x-rays localised the final position of the electrode. A company software matched sMRI, ventriculography, and peroperative (perop) x-rays, with reference to the stereotactic location boxes. We analysed the effects of acute (perop) and chronic (six-month follow-up) stimulation of active plots (acplots), i.e. leading to optimal clinical improvement. Three distances with reference to the acplots were measured both on sMRI and ventriculography: the laterality from the median sagittal plane of the third ventricle; the anterior position from the midpoint of the intercommissural line (Icl), and the vertical position with regard to the Icl. We then compared the differences in measurements (n = 64) with the Bland and Altman method. The mean difference was 0.09 mm with 95% of the values between +/- 1 mm, but only the laterality had a statistically significant agreement (all the differences included between +/- two times the standard deviation of the mean). The acplots distances from the dorsal, ventral, and medial boundaries of GP (defined by manual surrounding on frontal and horizontal planes) were measured on sMRI. With one exception, the acplots were all included in the nucleus. The six-month acplots were located dorsally with reference to the perop ones. Clinical benefit at six-months follow-up showed results comparable to the literature. Direct location of GP target based on sMRI seems a simple and reliable method.

Cerebral Ventriculography↗
PubMed1997

[Non-invasive monitoring of intracranial pressure changes through the ear].

Otoacoustic emissions are low energy vibrations generated by the inner ear during the physiologic process of hearing. The authors measured transiently evoked otoacoustic emissions in normal hearing individuals placed in Trendelenburg position and during diagnostic elevation of intracranial pressure in neurosurgical patients. In Trendelenburg position and at elevated intracranial pressure and reproducible phase shift of otoacoustic emissions could be observed. This phase shift was linear to the pressure increase of intracranial liquids. According to the hypothesis of the authors intracranial pressure increase is transmitted to the inner ear (possibly by the cochlear aqueduct) and thereby the mechanical load on the stapes footplate is elevated. This, in turn, causes a stiffening of the annular ligament which changes the angle of the impedance vector and thereby the phase of the whole vibrating system. By measuring the phase of otoacoustic emissions it is possible to monitor intracranial pressure in various clinical states.

Ear, Inner↗
PubMed1997

[Intracranial pressure monitoring in France, and French-speaking Belgium and Switzerland. Retrospective and prospective survey].

OBJECTIVE: To assess the use of ICP monitoring in France and French-speaking Belgium and Switzerland. PARTICIPANTS: Neuro-intensive care unit (ICU) and neuroanaesthesia teams. METHODS: Retrospective survey (concerning the year 1995), followed by a prospective one (spread over a period of 4 months in 1996) about policy concerning: frequency, delay, duration, indications, complications and cost of ICP monitoring in their units. Other questions were: type of devices, duration of the device insertion, operators and place of operating. RESULTS: Out of the 77 units which replied, 54 regularly carried out ICP monitoring, corresponding to a total of 2,012 patients in 1995. Only 23 participated in the prospective survey (301 patients). Out of the 54 hospitals, 25 assessed the ICP in more than 50 patients per year. Head trauma was the main indication for ICP monitoring (61%), the second indication was intracranial haemorrhage (23% of patients). The most often monitored patients were young males for head trauma, whereas females were mainly monitored for intracranial haemorrhage. The delay for starting ICP monitoring was 16 hours and was maintained for 7 days in head trauma patients. Intraventricular catheter and fibreoptic devices were chosen in the same proportion, a subdural system was used in 8% of the cases. The devices were inserted by neurosurgeons in 80% of cases, anaesthetists also participated in this operation. Risk of haemorrhage was very low (0.7%), the risk of infection was 4% and always concerned intraventricular catheters. CONCLUSION: ICP monitoring is widely practised in France and French-speaking Belgium and Switzerland, especially for traumatic brain injury in young males. Anaesthetists mainly took part in the operation, especially for the fibreoptic devices.

Adult↗
PubMed1996

Otoacoustic emissions: a new tool for monitoring intracranial pressure changes through stapes displacements.

Changes in hydrostatic intracranial pressure (ICP) are thought to be transmitted to cochlear liquids, thereby altering the mechanical load on the stapes footplate. Hence the stiffness of stapes' annular ligament is expected to reflect ICP changes. Corresponding middle-ear transmission changes have been assessed using click-evoked otoacoustic emissions (EOAE) in two experiments. The first one was performed in 22 normal human subjects submitted to posture changes. In the second one, controlled ICP increases were applied to 18 patients in neurosurgery operating theater. EOAEs were monitored in these subjects throughout the experiments and their phases and amplitudes were analyzed as a function of frequency. ICP affected EOAEs in a systematic manner in both experiments, i.e., the main effect of ICP increase was phase lead of EOAE components below 2 kHz without any significant amplitude or frequency shift. Their variations were much more evident than the modifications in middle-ear impedance assessed by standard impedance or admittance measurements. The second experiment led to a quantitative linear relationship between ICP and EOAE phases. It demonstrated that the sensitivity of EOAE phase monitoring technique proves to be quite high, i.e., 55 daPa increases in ICP are readily detected in all subjects. The results are consistent with the predictions of classical middle-ear models as to the transmission alterations induced by ICP-related changes in the stiffness of the annular ligament of the stapes. Non-invasive monitoring of ICP in patients with hydrocephalus treated with ventriculo-peritoneal shunts might be attempted with this technique, although it is restricted to patients with detectable EOAEs (i.e., about 50% in this series).

Acoustic Stimulation↗
PubMed1996

When is spinal fusion warranted in degenerative lumbar spinal stenosis?

This study, conducted by a group of neurosurgeons who devote a large portion of their professional time to the treatment of degenerative lumbar spine lesions, was prompted by the dramatic increase in the number of lumbar spinal fusion procedures performed over the last few years in a broad spectrum of disorders ranging from chronic incapacitating low back pain to lumbar spinal stenosis. In the authors' experience, lumbar spinal fusion is rarely warranted and often of dubious efficacy. To investigate this contradiction, the authors reviewed the medical literature on lumbar spinal fusion for the treatment of degenerative spinal stenosis. They have defined lumbar instability as objectively as possible, reviewed clinical and roentgenographic features, described spinal fusion techniques with the drawbacks of each, and evaluated outcomes of surgery for degenerative lumbar spinal stenosis with or without fusion. Findings demonstrate that spinal fusion is a technique of unproven benefit that should be used only in carefully selected patients until results of reliable, prospective, comparative clinical trials become available. In the authors' opinion lumbar spinal fusion should be used as the first-line treatment only in young patients with clinical manifestations directly related to lumbar instability as defined in this study, when decompression requires removal of both facet joints and of the disk (which is rarely the case) or when simple decompression is followed by a recurrence of symptoms ascribable to worsening vertebral slippage.

Adult↗
PubMed1995

Chronic ("normal pressure") hydrocephalus in childhood and adolescence. A review of 16 cases and reappraisal of the syndrome.

"Normal pressure" hydrocephalus (NPH) is generally considered to be a disorder of the adult and geriatric population. Only a few reports have described the possible occurrence of this condition in children. A series of 16 patients aged less than 20 years forms the basis of the present report. Among these 16 patients, 11 had a clearly identified etiologic factor and 7 had had a shunt previously implanted. The majority of patients exhibited at least two elements of the adult's triad of psychomotor retardation (14 cases) and/or psychotic-like symptoms (4 cases), gait anomalies (8 cases), and sphincter disturbances (3 cases). Six patients had their intracranial pressure (ICP) monitored. ICP values were estimated to be within the normal limits for age. All the 16 patients underwent shunting or shunt revision. Surgical results were as follows (mean follow-up 20 +/- 17.2 months): a good response to shunting was obtained in 12 cases ("cured": 5, improved: 7), while the other 4 patients failed to improve. It seems likely that associated parenchymal disorders have played a major role in therapeutic failures. In children showing ventricular dilation on computed tomographic (CT) analysis and a clinical picture of subtle psychomotor deterioration, it may be difficult to distinguish an active disorder of the CSF dynamics from "arrested hydrocephalus." Since intracranial manometry cannot be undertaken as a routine procedure, less invasive methods such as cerebrospinal fluid (CSF) tap test, psychometric, or urodynamic tests deserve special attention as reliable predictors of outcome after shunting. Because most patients undergo shunting without prior assessment of their CSF pressure, the term "chronic hydrocephalus" is proposed as an alternative designation to "NPH," since there is little argument for maintaining an instrumentally based definition of the syndrome.

Adolescent↗
PubMed1995

[Cancers in children in the Auvergne area: retrospective study from 1986 to 1991].

BACKGROUND: The specificity of childhood cancers led to the creation of regional childhood cancer registries. An epidemiological study of childhood cancers in the Auvergne area was carried out over a 6 year-period (1986-1991) in order to create a registry. POPULATION AND METHODS: The population of our study was 252,820 children (0-15 years old), living in the Auvergne region. All malignant neoplasms were included together with brain tumours (whatever grading). Data were collected from medical and administrative sources. RESULTS: The data of 153 cases were collected during this period. World age standardized overall incidence rate was 120.5 cases/milion/year. Age standardized incidence rates were: leukemias 37.6 (ALL 28.01), central nervous system tumours 18.34 (medulloblastomas 4.6, astrocytomas 4.6, ependymomas 3.8), lymphomas 10.0, neuroblastomas 18.6, soft tissue tumors 8.3, bone tumours 6.1 (Ewing's sarcomas 4.1, osteosarcomas 2.0), nephroblastomas 5.5, retinoblastomas 3.1, liver tumours 0.5 and others 0.5. CONCLUSIONS: Our data base in the Auvergne area might be a source of information for epidemiological studies on the role of etiological factors, the survival, the sequelae and the incidence trends.

Adolescent↗
PubMed1995

[Lumbar canal stenosis. Retrospective study of 158 operated cases].

The authors report the results of a retrospective study of 158 lumbar spinal stenosis (LSS), all operated (111 degenerative, 26 congenital, 21 mixed). Eighty seven percent of the patients had a low-back pain and 81.6% a radicular pain. Only 57.6% of them had a polyradicular claudication. A neurological deficit (motor, sensitive, or involving sphincters) was present in 36.6% of cases. A myelographic block was noted in 23.4% of cases, and in 20.3% a spondylolisthesis with an intact neural arch was found. Surgery consisted of a posterior lateral spinal canal calibration, sometimes associated with a ventral canal calibration (via the posterior route) (6.3%), and/or excision of a disc herniation at one (47.5%) or two levels (3.8%). Mean follow-up after surgery was 7.8 months. The global result was good or excellent in 75.2% of cases. Radicular pain was relieved in 89.1% of cases, and polyradicular claudication in 90.1% of cases. Neurological deficit improved in 50.6% of cases. In only 59.8% of cases relief of low-back pain was achieved. Statistically low-back pain (lasting for over 2 years) improved less, but a preoperative spondylolisthesis didn't influence the quality of the result regarding this symptom. Semiology, pathophysiology, and surgery particularly regarding spine stability are discussed.

Adult↗
PubMed1994

A computer software for frequential analysis of slow intracranial pressure waves.

A microcomputer program to analyse ICP signal in the frequential domain is described. It allows the detection and quantification of especially slow pressure waves (A, B, and C). 212 ICP data recordings were analysed with our software, and gave pertinent frequential informations. The status report and lessons learned are discussed.

Adolescent↗
PubMed1994

[Stereotaxic biopsies of pineal tumors. Comments on their risk and implication apropos of 370 cases].

370 stereotactic biopsies of pineal region tumors, from 15 neurosurgical centers in France have been reviewed with the goal to evaluate the mortality/morbidity rates and diagnostic yield of this procedure. The impact of neuroradiological means of localisation, the probe trajectory, the type of biopsy instrument, the time of shunting are discussed in order to maximize the diagnostic yield and minimize the mortality/morbidity rates. Stereotactic biopsy contribution, as compared to other diagnostic methods, in pineal region tumors was evaluated. The mortality rate was 1.3 % (5 patients of 370), 3 patients suffered severe neurological complication. In relation to the large number of patients in this study, we can assess that the mortality rate of stereotactic biopsy in this region doesn't significantly exceed that of stereotactic brain tumor biopsies in general.

Adolescent↗
PubMed1993

[Neuroblastoma in the Auvergne region from 1986 to 1991: epidemiological data].

An epidemiological study of neuroblastoma in the Auvergne area of France (departments: Puy-de-Dôme, Allier, Cantal, Haute-Loire) was carried out over a 6 years period (1986-1991). Nineteen cases of neuroblastoma were registered during this period. The annual incidence rate is 1.2 among 100,000 children under the age of 15 years. Similar incidence rates from other studies have been reported in the literature. In the department of Rhône, France, a screening program for neuroblastoma was initiated in 1990. The Auvergne area may constitute a population-based control group.

Child↗
PubMed1992

Mechanisms of orientation of the pelvifemoral base during static loading of the lumbar spine in weight-lifters.

Under static loading during weight-lifting, the lumbosacral spine essentially exhibits horizontalisation of the base of the sacrum (superior plateau of S1). We have attempted to elicit the mechanism of this horizontalisation by means of radiographs. These do not demonstrate any movements of the sacroiliac joints or plasticity of the hip bones. However, a symmetrical rotation of the hip joints conditions a retroversion of the pelvic girdle which explains the horizontalisation of the upper sacral plateau. This fixation of the block of the pelvic girdle is under muscular control, so that this mechanism can be improved by appropriate training.

Adult↗
PubMed1991

[Osteoporosis, arachnoid cyst and conus medullaris compression].

The authors report the case of a 75-year-old woman with an osteoporotic vertebral crush fracture of L1, without detectable vertebral necrosis, with signs of conus medullaris compression. The outcome at 2 years was satisfactory with complete recovery of neurological impairment after laminectomy from T12 to L2 and evacuation of a compressive arachnoid cyst overlying L1. This rare case is remarkable because of the presence of an arachnoid cyst. The role of the latter in the pathogenesis and progression of the neurological lesions is discussed.

Aged↗