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Biomedical subjects

O Vernet

Publications and source records attributed to O Vernet.

At least 19 recordsLinked to original sources
PubMed2007

Third ventriculostomy vs ventriculoperitoneal shunt in pediatric obstructive hydrocephalus: results from a Swiss series and literature review.

INTRODUCTION: Few series compare endoscopic third ventriculostomies (ETV) and ventriculoperitoneal shunts (VPS). To avoid the complications after a shunt insertion, there is an increased tendency to perform a third ventriculostomy. We reviewed all pediatric patients operated in the French-speaking part of Switzerland for a newly diagnosed obstructive hydrocephalus since 1992 and compared the outcome of patients who benefited from ETV to the outcome of patients who benefited from VPS. There were 24 ETV and 31 VPS. DISCUSSION: At 5 years of follow-up, the failure rate of ETV was 26%, as compared to 42% for the VPS group. This trend is also found in the pediatric series published since 1990 (27 peer-reviewed articles analyzed). CONCLUSION: In accordance to this trend, although a statistical difference cannot be assessed, we believe that ETV should be the procedure of choice in pediatric obstructive hydrocephalus.

Adolescent↗
PubMed2004

The origin of brain metastases in patients with an undiagnosed primary tumour.

BACKGROUND: In patients presenting brain metastases as the first manifestation of a previously undiagnosed primary tumour (UDP) histopathological confirmation of the diagnosis can be obtained by either direct surgical sampling of the brain lesion or paraclinical search for an accessible primary tumour. The sequence of the diagnostic work-up and the timing of an eventual neurosurgical intervention are a matter of debate and are mainly influenced by the distribution of primary tumours in UDP patients. The aim of this study was to verify the hypothesis that the distribution of primary tumours differs between UDP patients and the rest of the patients with brain metastases (DP), and to propose a diagnostic work-up specifically tailored to the UDP population. METHODS: Retrospective study on 342 patients admitted to the Lausanne University hospital between 1983 and 1998 with the diagnosis of cerebral metastases. FINDINGS: UDP patients represented 36% of the whole group. Primary tumour location was significantly different between the two groups (p=0.001). Although the lung was the most frequent primary tumour location in both groups (UDP: 60%, DP: 43%), in UDP 14% only of the primaries were found outside of the lung and as much as 26% remained unknown despite thorough investigations. CONCLUSIONS: Our study confirmed the hypothesis that the relative frequency of primary tumours differs between DP and UDP patients. This difference therefore mandates a diagnostic strategy specifically tailored for UDP patients: if a radiological lung investigation clearly remains the best initial step in the work-up of these patients, extensive paraclinical investigations without a clear clinical suspicion should probably not be undertaken if this first survey fails to disclose the primary tumour as only 14% of the patients will actually benefit from it. In this situation, a neurosurgical procedure should probably be considered the most appropriate next step to be taken in order to provide a definitive diagnosis without unnecessary delays.

Adult↗
PubMed2004

Ruptured cerebral aneurysm in the early stage of life--a congenital origin?

We report the case of a large fusiform aneurysm of the anterior cerebral artery in a 3-month-old girl presenting with generalized seizures and complicated by a cardiorespiratory arrest needing resuscitation. The native cerebral CT scan revealed a diffuse subarachnoid hemorrhage (Fischer III grade); CT angiography showed an aneurysm of the distal A1 segment of the anterior cerebral artery (ACA). Successful treatment was achieved through surgical trapping of the aneurysm and sacrifice of the distal A1 segment. A histological study of the aneurysmal wall revealed the absence of elastic fibers in an otherwise fibromuscular media and showed no signs of previous hemorrhage. Intracranial aneurysms of the ACA are very rare in the early stage of life and their pathogenesis is not clear. This case is of interest as the location and shape of the aneurysm, the absence of relevant familial and medical history, and the histopathological findings raise the hypothesis of a congenital origin. It further describes the value of CT angiography for studying aneurysms in the very young.

Aneurysm, Ruptured↗
PubMed2003

Non-obstructive hydrocephalus associated with intracranial schwannomas: hyperproteinorrhachia as an etiopathological factor?

BACKGROUND: This series illustrates the association of communicating hydrocephalus with intracranial non-obstructive schwannomas. This association has commonly been observed, however it has only been reported once previously. Moreover, in all the patients we present, hyperproteinorrhachia was a common denominator. This finding may therefore be the underlying mechanism for hydrocephalus. METHOD AND FINDINGS: Seven patients presenting with intracranial schwannomas along with non-obstructive hydrocephalus and hyperproteinorrhachia are reported. Six had a vestibular schwannoma and presented with a unilateral deafness and various degrees of gait disturbance, urinary incontinence and neuropsychological impairment. Due to their advanced ages, these patients underwent a ventriculo-peritoneal shunt, and their symptoms related to hydrocephalus resolved. One patient that suffered from hemifacial dysesthesia and memory deficits presented with a non-obstructive trigeminal schwannoma. In this case the tumour was removed and the hydrocephalus was consequently reversed, and the CSF protein content normalized. INTERPRETATION: The constant finding of hyperproteinorrhachia in all these patients suggests that a high CSF protein content may be the underlying cause of hydrocephalus through a speculative mechanism of decreased CSF resorption.

Adult↗
PubMed2000

Dysgenetic mesial temporal sclerosis: an unrecognized entity.

Mesial temporal sclerosis (MTS) is the most frequently encountered lesion in adult patients with intractable temporal epilepsy; it is found in isolation in approximately two-thirds of surgically treated cases. Whereas the exact etiology of MTS is still controversial, several reports suggest that this pathologic lesion is both the cause and the consequence of chronic seizures and develops progressively during childhood secondary to recurrent seizures. In order to evaluate the clinical importance of MTS in children, we retrospectively reviewed the clinical charts of children who underwent surgery for medically intractable temporal epilepsy and report cases presenting an amygdalo-hippocampic dual pathology. Six children aged 1.5-16 years (mean +/- SD: 7.5 +/- 3 years) presenting with partial complex seizures (5 cases) or extension spasms (1 case), with onset from 6 months to the age of 8.5 years (mean seizure onset +/- SD: 3 +/- 5 years) underwent anterior temporal lobectomy including resection of the amygdala and hippocampus. All patients exhibited variable degrees of severity of neuronal loss and gliosis in the amygdala and/or hippocampus. The pathological picture of MTS was not isolated, however. Careful pathological examination has thus shown foci of amygdalo-hippocampic neuronal dysplasia in six patients, with concomitant bilaminated fascia dentata in two cases. Postoperatively, no mortality or morbidity was encountered. After a mean follow-up of 2.5 years, four patients are seizure free. One patient had a 80% rate of improvement in seizure frequency, though still having occasional febrile convulsions. In another patient, complex partial seizures resolved, but rare episodes of absence were still observed. These data are in keeping with the hypothesis that MTS could be secondary to repeated seizures. The analysis of this series of patients could suggest that mesiotemporal dysplastic lesions within the amygdalo-hippocampic structures induce seizures, which, in turn, will favor the development of MTS during childhood. MTS could then lead to synaptic reorganization, which can express abnormal hyperexcitability and result in more recurrent seizures. In this way a vicious circle is set up, which may explain the progression of seizures in some patients.

Adolescent↗
PubMed2000

Gliomas in children: a review.

The management and prognosis of gliomas are significantly different in children and in adults. Fortunately, the proportion of gliomas that are malignant is smaller in children than in the adult population. The different types of gliomas encountered in the pediatric population are reviewed, taking account of the most recent contributions on this subject. The importance of considering both localization and histological classification for better definition of the prognostic factors of each subgroup is emphasized. A brief review of the possible causes of gliomas is presented. Unfortunately, the information obtained by molecular and genetic study of these tumors has still not resulted in anything that can help the children suffering from gliomas in a concrete way. Surgery, with all its recent refinements, remains the best treatment for the majority of benign gliomas providing they can be removed without unacceptable sequelae. The role of chemotherapy has emerged recently for the treatment of nonresectable low-grade gliomas, such as hypothalamic-chiasmatic tumors, especially for infants, in whom the adverse effects of radiotherapy can be severe and irreversible. On the eve of the new millennium, there is renewed hope that the problem of malignant gliomas will be solved in the not-too-distant future.

Brain Neoplasms↗
PubMed1999

Long term results of multimodality treatment of craniopharyngioma in children.

The management of craniopharyngioma has been controversial for years. We review our 20 year experience in the treatment of paediatric craniopharyngioma. Twenty-five patients were treated for craniopharyngioma at The Montreal Children's Hospital from 1972 to 1991. They included 15 males and 10 females whose median age was 10 years. The initial clinical manifestations were remarkable for a predominance of symptoms and signs related to intracranial hypertension, followed in frequency by visual and endocrinological deficits. Radiologically, there were five cystic craniopharyngiomas, one solid and 19 mixed. Several therapeutic approaches were used including stereotactic drainage followed by radiotherapy or radiosurgery (three cases), transsphenoidal removal (six cases) and subfrontal and/or pterional craniotomy for total (three cases) or partial (13 cases) removal, followed by radiotherapy in 10 cases. The follow up period averaged 11 years. Eight patients recurred, three after total and three after partial removal; none of these six patients had received radiotherapy. Two cases treated by stereotactic drainage recurred, one received adjuvant radiosurgery and the other conventional radiotherapy. Morbidity was lower, and quality of survival better, with more conservative approaches. More conservative approaches in the management of craniopharyngioma are reasonable alternatives for treatment. Similar rates of disease control are observed with less morbidity and better quality of survival. Copyright 1999 Harcourt Publishers Ltd.

Journal Article↗
PubMed1998

Sleep-disordered breathing in children with myelomeningocele.

BACKGROUND: Although patients with myelomeningocele and the Chiari II malformation are known to have sleep apnea and respiratory control deficits, the prevalence, types, severities, and associations of sleep-disordered breathing (SDB) have not been adequately defined. METHODS: A cross-sectional study of our myelomeningocele clinic population was undertaken to correlate polysomnographic results with historical data and findings from magnetic resonance imaging of the Chiari malformation, pulmonary function results, and nocturnal pulse oximetry. RESULTS: A questionnaire survey of symptoms was available for 107 of 109 children (98% of the clinic population), and 83 patients agreed to undergo overnight polysomnography. Breathing during sleep was classified as normal in 31 cases (37%), mildly abnormal in 35 cases (42%), and moderately/severely abnormal in 17 cases (20%). Among the 17 patients with moderately/severely abnormal SDB, 12 patients had predominantly central apneas and 5 had predominantly obstructive apnea. Patients with a thoracic or thoracolumbar myelomeningocele, those who had previously had a posterior fossa decompression operation, those with more severe brain-stem malformations, and those with pulmonary function abnormalities were more likely to have moderately/severely abnormal SDB, relative risks (95% confidence intervals) 9.2 (2.9 to 29.3), 3.5 (1.3 to 8.9), 3.0 (0.9 to 10.5), and 11.6 (1.6 to 81.3), respectively. Failure of obstructive SDB to resolve after adenotonsillectomy in four patients suggested abnormal control of pharyngeal airway patency during sleep. Nocturnal pulse oximetry accurately predicted moderately/severely abnormal SDB with a sensitivity of 100% and a specificity of 67%. CONCLUSIONS: The pathogenesis of SDB in patients with myelomeningocele involves the functional level of the spinal lesions, congenital and acquired brainstem abnormalities, pulmonary function abnormalities, disorders of upper airway maintenance, and sleep state. Polysomnography and nocturnal pulse oximetry should be performed in high-risk patients to detect and classify SDB.

Arnold-Chiari Malformation↗
PubMed1998

Magnetic resonance imaging in children with voiding dysfunction: is it indicated?

PURPOSE: We evaluated the role of magnetic resonance imaging (MRI) of the lumbosacral spinal cord in children with complicated voiding dysfunction and normal neuro-orthopedic examination. MATERIALS AND METHODS: We reviewed the records of 32 consecutive children with complicated enuresis who were referred for neurosurgical evaluation, including those with a history of refractory voiding dysfunction or incontinence associated with persistent vesicoureteral reflux, encopresis, or associated leg or back pain. Nine patients were excluded from study because of urethral or anorectal anomalies, or failure to meet the inclusion criteria. Eligible for study inclusion were 23 children with a mean age of 8.9 years. Complete neurological and orthopedic examinations were normal in all patients except 1 with mild scoliosis and 1 with congenital facial palsy. RESULTS: Urodynamic studies revealed instability in 14 cases, hypertonia in 7, hyporeflexia in 2 and detrusor-sphincter dyssynergia in 4. Skeletal abnormalities, mostly spina bifida occulta, were detected in 16 of the 23 children (70%). Spinal MRI was normal in 21 patients (91.3%), including 1 with a tethered cord and lipoma associated with a complex skeletal abnormality, and 1 with a nonprogressive, nonsurgical T7 to T9 syrinx. Only the case of lipoma required neurosurgical intervention. CONCLUSIONS: The value of MRI is limited in children with voiding dysfunction and a normal neuro-orthopedic assessment. This study should be reserved for patients with associated neuroorthopedic findings or complex skeletal deformity on plain x-ray.

Adolescent↗
PubMed1998

Bladder function before and after selective dorsal rhizotomy in children with cerebral palsy.

PURPOSE: Approximately a third of children with cerebral palsy are expected to present with dysfunctional voiding symptoms. Selective dorsal rhizotomy, which is indicated for managing lower extremity spasticity in children with cerebral palsy, also has the potential of affecting bladder function. We evaluate the impact of selective dorsal rhizotomy on bladder function by comparing preoperative and postoperative symptoms, and urodynamic parameters in children undergoing selective dorsal rhizotomy for spasticity. MATERIALS AND METHODS: We reviewed urodynamic studies in 25 boys and 15 girls with a mean age plus or minus standard deviation of 5.43+/-2.1 years who underwent selective dorsal rhizotomy for spasticity at our institution between January 1992 and September 1995. Urodynamics were performed preoperatively only in 22 patients, preoperative and postoperatively in 13, and postoperatively only in 5. Preoperative urodynamic studies were done within 2 weeks of surgery and postoperative studies were done at least 6 months after surgery (mean 1.32+/-0.65 years). RESULTS: Of the 35 patients with preoperative urodynamic studies total bladder capacity, pressure specific volumes and full resting pressure were abnormal for age in 23 (65.7%). In addition, 17 of the 23 children (74%) were completely asymptomatic. In the group that underwent preoperative and postoperative urodynamic studies there was significant improvement in total bladder capacity (p <0.005) and pressure specific volumes (p <0.005) using the paired Student t test. All children had neurological improvement postoperatively, 5 of 7 (71%) who were incontinent preoperatively became continent and none had deterioration on urodynamics. CONCLUSIONS: At least half of the children with spastic cerebral palsy have clinically silent bladder dysfunction. Selective dorsal rhizotomy improves spasticity and significantly improves bladder storage characteristics. We propose that urodynamic studies be included in the evaluation of children with spastic cerebral palsy who are possible candidates for selective dorsal rhizotomy to treat lower limb spasticity.

Cerebral Palsy↗
PubMed1998

Continuous unilateral epileptiform discharge and language delay: effect of functional hemispherectomy on language acquisition.

PURPOSE: To assess the efficacy of functional hemispherectomy in promoting language acquisition in a child with severe language delay and continuous left hemispheric epileptiform discharge in the absence of clinical seizures. We report a 6-month-old girl who initially presented with a right hemiparesis secondary to a lesion of probable prenatal origin in the distribution of the left middle cerebral artery. Weeks later, she developed infantile spasms. At 1.5 years of age, because of intractable seizures, the patient had fenestration of the left porencephalic cyst and anterior temporal lobectomy. The seizures ceased; however, language development remained limited to 35 words at 3.5 years of age. The EEG showed almost continuous epileptiform activity over the left hemisphere with no independent epileptiform potentials contralaterally. She underwent a functional left hemispherectomy. METHODS: Imaging, electroencephalographic investigation, pre- and postoperative psychological and speech assessment were carried out. RESULTS: Considerable language, speech, and behavior improvement was noted within 2 months of surgery. CONCLUSIONS: Interictal epileptiform discharges can interfere with the development of contralateral hemispheric function in the absence of clinical seizures. Early functional hemispherectomy may have a role in promoting optimal language development in appropriately selected patients. Although the primary indication for functional hemispherectomy is to control intractable seizures, a secondary proposed indication is to reduce functional impairment of the other hemisphere by electrical interference.

Brain↗
PubMed1996

Encephaloduroarterio-synangiosis in a child with sickle cell anemia and moyamoya disease.

We report a black girl with sickle cell anemia. On prophylactic exchange transfusion protocol, she experienced cerebrovascular accidents at 3 and 3.5 years of age, both associated with transient right hemiparesis. At 7.5 years of age, she presented with a partial motor seizure and a left hemiparesis. A cerebral angiogram demonstrated stenosis at the origins of both middle and anterior cerebral arteries bilaterally with extensive basal collateralization. She underwent uncomplicated bilateral encephaloduroarteriosynangiosis (EDAS) procedures using both superficial temporal arteries. At age 9 years, the patient presented with a severe headache and tunnel vision secondary to a stenosis of both posterior cerebral arteries. She underwent bilateral EDAS procedures using both occipital arteries. No complication was encountered. Postoperative cerebral angiogram demonstrated impressive neovascularity at the sites of all four EDAS procedures. Different treatment options of moyamoya disease are discussed.

Anemia, Sickle Cell↗
PubMed1996

Use of the prone position in the MRI evaluation of spinal cord retethering.

In order to determine the impact of magnetic resonance imaging (MRI) in the management of spinal cord retethering, we retrospectively reviewed case and imaging records of 51 patients who underwent MRI examination in supine and prone positions. Group 1 included 8 control patients without cord tethering. They exhibited a normal level of the conus medullaris with normal surrounding subarachnoid space, and consistent anterior migration of the conus within the dural sac on MRI in prone position. Group 2 included 17 patients with tethered cord secondary to occult spinal dysraphism (spinal cord lipoma in 6 patients, thick filum terminale in 4, diastematomyelia in 4, myelomeningocele manqué in 2, and dermoid tumour in 1). Supine and prone MRI performed at a median period of time of 6 months after untethering showed resolution of posterior tethering in 5 out of the 7 patients who exhibited pre-operatively dorsal attachment of the spinal cord to the dura. Anterior migration of the conus or of the cord/filum complex in prone position was observed in only 24% of the cases. Group 3 included 26 patients with secondary tethered cord following prior myelomeningocele closure. Their MRI performed at a median interval of time of 11 months following untethering demonstrated resolution of the posterior cord tethering in only 8 out of the 24 patients who exhibited this feature pre-operatively. Anterior migration within the expanded dural sac was never noted in this group. We conclude that spine MRI is of limited value and that prone-positioned MRI is of no additional use in the evaluation of spinal cord retethering.

Adolescent↗
PubMed1996

Comparison of syringopleural and syringosubarachnoid shunting in the treatment of syringomyelia in children.

Case records from the Montreal Children's Hospital containing the diagnosis of shunted syringomyelia were retrospectively reviewed. From 1984 to 1994, 31 patients had their syrinx treated by either syringopleural (19 cases, Group A) or syringosubarachnoid (13 cases, Group B) shunting. One patient was included in both groups. Associated diagnoses included: in Group A, two cases of Chiari I and 14 of Chiari II malformations, 14 cases of shunted hydrocephalus, 13 cases of spina bifida aperta, and three cases of spina bifida occulta; Group B, four cases of Chiari I and two of Chiari II malformations, four cases of shunted hydrocephalus, two cases of spina bifida aperta, and five cases of spina bifida occulta. Eight Group A and six Group B patients had undergone prior posterior fossa decompression. Motor deficits predominated in both groups and arachnoiditis was a uniform operative finding. Neurological follow-up examinations showed 11 Group A patients improved and eight stabilized, whereas on magnetic resonance imaging, 12 cavities appeared to have collapsed, five were markedly reduced, and one had increased. One patient underwent reoperation for pleural effusions and one for shunt displacement. In Group B, one patient improved, eight stabilized, three worsened neurologically, and one was lost to follow-up review. Radiologically, one cavity appeared to have collapsed, six were significantly reduced, two were unchanged, and three had enlarged. The authors conclude that syringopleural shunting is a valuable option for controlling syringomyelia in patients without Chiari malformation or in patients who have previously undergone a craniovertebral decompression or are otherwise asymptomatic from their Chiari malformation.

Adolescent↗
PubMed1996

Impact of urodynamic studies on the surgical management of spinal cord tethering.

To determine the usefulness of urodynamic studies in the management of children with a suspected tethered spinal cord, the authors retrospectively reviewed case records of 25 patients evaluated both pre- and postoperatively using this diagnostic adjunct. All patients were also evaluated with magnetic resonance imaging or computerized tomography myelography. Seven patients who presented initially with orthopedic deformity, skin stigmata, and neurological problems underwent primary cord untethering (Group 1). All seven patients were urologically asymptomatic; all but one had normal findings on urodynamic study. Eighteen patients with prior myelomeningocele closure underwent secondary untethering (Group 2). They presented with urological (11 cases), neurological (three cases), or both urological and neurological (four cases) deterioration. All patients underwent surgery via a microsurgical technique. At a mean follow-up time of 2 years, the only Group 1 patient with preoperative abnormal urodynamic findings normalized following untethering, whereas another asymptomatic patient showed worsened results on his postoperative study. In Group 2, all seven patients with preoperative neurological deterioration improved. Ten of the 15 patients who had isolated or associated preoperative clinical urological deterioration improved or stabilized, whereas five displayed continued deterioration in their bladder function. With respect to urodynamic studies, there was a significant increase in total and pressure-specific bladder capacities following untethering. We conclude that urodynamic studies are useful both diagnostically and in follow-up examinations of patients with tethered cord, that disturbances identified by these studies often precede clinical manifestations of deterioration, and that spinal cord untethering favorably influences the urological status in most patients.

Adolescent↗