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Biomedical subjects

O Vernet

Publications and source records attributed to O Vernet.

At least 37 records · Page 2Linked to original sources
PubMed1996

Radionuclide shuntogram: adjunct to manage hydrocephalic patients.

UNLABELLED: We reviewed our experience with shuntograms to establish technical criteria that would optimize the reliability of this test in managing patients with shunt malfunction. METHODS: Fifty-six shuntograms were performed in 47 children presenting with symptoms of shunt malfunction not elucidated by conventional radiological examination. Shuntograms were performed by injecting 0.5 ml 99mTc-DTPA in the reservoir of the shunt. RESULTS: There were 22 shuntograms in which ventricular reflux occurred and the entire shunt system was visualized. At surgery, three patients in this group presented partial obstruction of the ventricular and/or peritoneal catheter. A second group of patients had 15 shuntograms that showed normal proximal reflux but abnormal distal drainage. Ten patients in this group presented distal obstruction or fracture, valve dysfunction or peritoneal adhesions at surgery. A third group of patients with 19 shuntograms exhibited no proximal reflux. At surgery, twelve had an obstructed ventricular catheter and the last case showed overdrainage. Symptoms of nonsurgical patients abated spontaneously. CONCLUSION: The shuntogram is a useful procedure in the management of patients presenting with shunt-related problems. For consideration as a normal result, a shuntogram must exhibit ventricular reflux, the shunt system must be entirely visualized and the isotope must diffuse uniformly in the peritoneal cavity. Whereas rapid radionuclide clearance is a useful parameter in eliminating a distal obstruction. It is a misleading sign for proximal blockage. Absence of ventricular reflux is highly suggestive of proximal reflux. Implicit to this conclusion is the fact that the presence of a reservoir proximal to the valve greatly facilitates the performance and interpretation of a shuntogram.

Child↗
PubMed1995

Long-term results after ventriculo-atrial shunting in children.

A consecutive series of 120 patients with infantile hydrocephalus who were submitted to ventriculo-atrial shunting was studied. The average follow-up was 11 years. There was no operative mortality; 7 patients died during the follow-up period, but only in 1 case was the cause of death a consequence of the shunt procedure. The incidence rates of infection and slit ventricle syndrome were 4.2% and 1.8%, respectively. Shunt revision was performed on 253 occasions yielding a revision rate of 2.2 per patient. Of these 253 revisions 167 (66%) took the form of elective lengthening of the atrial catheter. The number of reoperations to adjust the length of the atrial catheter or to revise the distal end of the shunting system is a major disadvantage, which actually favors ventriculo-peritoneal shunting as the primary procedure for the treatment of pediatric hydrocephalus.

Cerebrospinal Fluid Shunts↗
PubMed1995

Supratentorial ectopic ependymoma.

BACKGROUND: Ependymomas usually arise from the ventricular surface. METHODS: We report an 11-year-old female who presented with a supratentorial ectopic ependymoma. RESULTS: The patient presented with a two-month-history of progressive headache, nausea and vomiting. Examination revealed papilledema, horizontal nystagmus, diplopia on upward gaze, and right pronator drift. CT scan showed an enhancing left precentral subcortical lesion measuring 3 cm in diameter with associated edema and mass effect. Its medial border was located 3 cm from the ependymal surface of the ventricle. A firm tumour was dissected from the centrum semiovale white matter, and removed in toto as confirmed on MRI. Pathological examination revealed histological, immuno-histochemical and electron microscopic features consistent with an ependymoma. Spine MRI and bone marrow aspirate, as well as lumbar puncture of cytology failed to show any dissemination. CONCLUSION: From the literature review, this represents an exceptional ependymoma located at the distance from the ventricular system or cisterns. Different pathogenic alternatives are discussed.

Brain Neoplasms↗
PubMed1993

Long-term results after ventriculoatrial shunting in children.

A consecutive series of 120 patients with infantile hydrocephalus who were subjected to ventriculoatrial shunting was studied. The average length of follow-up was 11 years. Operative mortality was zero. Seven patients died during the follow-up period; in all cases but one of these the cause of death was not a consequence of a shunt-related procedure. The incidences of infection and slit ventricle syndrome were 4.2% and 1.8% respectively. Two hundred and fifty-three shunt revisions were performed, yielding a revision rate of 2.2 per patient. Of these 253 revisions 167 (66%) were elective lengthening of the atrial catheter. The number of reoperations for adjusting the length of the atrial catheter of for revision of the distal end of the shunting system is a major disadvantage of ventriculoatrial shunting which actually speaks in favor of ventriculoperitoneal shunting as the primary procedure for the treatment of pediatric hydrocephalus.

Adolescent↗
PubMed1993

Pre- and postoperative urodynamic and anorectal manometric findings in children operated upon for a primary tethered cord.

The aim of the study was to assess the sensitivity of both urodynamics and anorectal manometry in detecting neurological signs in children with a primary tethered cord. Between 1989 and 1991, 9 children were operated upon for untethering of primary tethered cord in Lausanne. Both manometric studies were performed by the same team preoperatively and 6 months after surgery. Gaeltec catheters with micro-tip transducers were used with a standardized method. Preoperative manometric findings were pathological in 4 children without clinical signs of bladder dysfunction and in 3 without clinical fecal disorders. Postoperatively, bladder dysfunction regressed in one child and fecal disorders in another. Manometric findings remained nevertheless pathological. The authors held both urodynamics and anorectal manometry as mandatory for preoperative evaluation as well as for the postoperative monitoring of children with primary tethered cord.

Adolescent↗
PubMed1993

Giant cell tumor of the orbit.

Giant cell tumors of the skull are very rare and usually occur in the sphenoid bone. The authors report the case of a 10-year-old boy with such a tumor involving exclusively the roof of the left orbit. He presented essentially with edema of the left superior eyelid and diplopia. Computed tomographic examination and magnetic resonance imaging delineated the lesion, which was radically removed via a left fronto-orbital craniotomy. Some aspects of this rare neoplasm are reviewed.

Cerebral Angiography↗
PubMed1992

Protein kinase C activity and subcellular distribution in rat brain following repeated electroconvulsive seizures.

Protein kinase C (PKC) activity was measured in samples of neocortex, cerebellum, and hippocampus from adult rats receiving a series of 10 electroconvulsive seizures (ECS). Rats were sacrificed immediately and at various intervals from 15 min to 24 h after the last seizure. From 77 to 84% of total PKC activity was found in the cytosol versus the membrane fraction. PKC activity in cerebellum was significantly higher than in neocortex (15%, P less than 0.05). Repeated ECS treatment did not affect total PKC activity nor its distribution between membrane and cytosolic fractions when compared with sham ECS controls. This finding is in keeping with reports that adrenergic-stimulated phosphoinositol turnover is not altered 24 h following repeated ECS.

Animals↗
PubMed1991

Protein kinase C activity and intracellular distribution in surgically excised human epileptic neocortex.

Protein kinase C (PKC) activity assayed by phosphorylation of exogenous histone, was measured in neocortex obtained from 32 patients following surgery for focal epilepsy and from 6 non-epileptic patients. PKC activity was not significantly different in either the particulate or cytosolic fraction from epileptic foci (n = 17) versus samples from non-spiking regions (n = 22) or neocortex from non-epileptic patients (n = 6). From 67% to 70% of total PKC activity was present in the cytosolic fraction. Phosphorylation of endogenous cytosolic substrate proteins was also not significantly different in epileptic foci.

Biopsy↗
PubMed1991

Biochemical markers of excitability in human neocortex.

We measured biochemical markers of excitability in brain excised for neurosurgical therapy of epilepsy. Intraoperative electrocorticography was used to identify and compare samples from regions of persistent interictal spike discharges and areas of the cerebral convexity which were free of interictal spiking. We found that interictal spiking was associated with elevated tissue levels of the excitatory amino acids glutamic acid (26%, p less than 0.001) and aspartic acid (25%, p less than 0.05). There was also a significant increase in the activity of the enzymes glutamic acid dehydrogenase (20%, p less than 0.01) and aspartate acid aminotransferase (18%, p less than 0.01) which are involved in their formation. There was no change in the levels of the inhibitory neurotransmitters GABA or taurine. We also found a significant increase in the activity of tyrosine hydroxylase (52%, p less than 0.001), the rate controlling enzyme in catecholamine biosynthesis. There was a reduction in the density (Bmax) of cortical alpha-1 adrenoceptors (26%, p less than 0.01) and a concomitant diminution of receptor coupled phosphatidylinositide metabolism (21%, p less than 0.01). This blunting of inhibitory noradrenergic transmembrane signaling may contribute to a relative imbalance between excitatory and inhibitory mechanisms in epileptogenic neocortex.

Amino Acids↗
PubMed1991

Atlantoaxial mobility after screw fixation of the odontoid: a computed tomographic study.

Between 1979 and 1989, anterior screw fixation of the odontoid process was performed in 16 patients with fractures of the odontoid. One patient died suddenly 2 days after the operation. Postmortem examination could not disclose the cause of death. No other complication was noted. We followed 13 patients. At examinations 7 to 82 months after injury, all fractures were consolidated in reduced position. In all patients, a functional computed tomographic (CT) examination of the atlantoaxial rotation was performed. Atlantoaxial rotation measurement ranged from 7 to 38 degrees to the right (average: 25.2 degrees) and 7 to 41 degrees (average: 24.1 degrees) to the left side. Five patients presented a normal range of atlantoaxial rotation, 29 to 41 degrees; 3 had a rotation of 20 to 28 degrees; 3 a rotation of 10 to 20 degrees; and in 2, rotation was less than 10 degrees to one side. Our results suggest that anterior screw fixation is the therapy of choice for Type II and cephalad Type III dens fractures. However, significant complications have been reported by other authors. Therefore, a careful surgical technique is mandatory, and contraindications should be respected.

Adolescent↗
PubMed1991

Cyst of the ligamentum flavum: report of six cases.

Six cases of cyst of the ligamentum flavum with compression of a lumbar nerve root are reported. All patients exhibited recurrent back pain and sciatica. Investigation included computed tomography, myelography, or both. The correct diagnosis was reached before operation in only half the patients. High-resolution computed tomography performed in the four last patients outlined the cystic lesion with its low-density center. Surgical excision was performed in all patients. Microscopic examination showed a dense fibrous cyst arising from the ligamentum flavum. The lumen contained myxoid or necrotic material, but no epithelial lining. Cysts of the ligamentum flavum must be considered in the differential diagnosis of causes of sciatica. A firm radiological diagnosis may, at present, still require myelography combined with high-resolution computed tomography. Differentiation from synovial or ganglion cysts of the spine is discussed.

Aged↗
PubMed1991

Enthesopathy of the tuberositas radii. A diagnostic problem.

The radial tubercle is rarely the site of enthesopathy. When it occurs, symptoms and radiological images are usually typical enough for unequivocal diagnosis. We report the case of a man with atypical pain and X-rays modifications of the radial tubercle. Correct diagnosis was established by histological analysis. Better knowledge of this pathology should prevent unnecessary excision.

Elbow Joint↗
PubMed1989

[Osteoid osteoma of the lower end of the femur--a diagnostic problem].

Joint symptoms may be the first manifestations of juxta-articular osteoid osteoma; therefore, diagnosis may be difficult. We report the case of a young athlete who presented an osteoid osteoma of the distal part of the femur. Correct diagnosis was delayed by the presence of a pathological mid-patellar plica synovialis and the absence of modifications on standard X-rays.

Adult↗
PubMed1989

[Tamponade and central venous catheter. Apropos of a case].

We report the case of a patient who developed cardiac tamponade after insertion of a central venous catheter. Often in such situations the first symptoms of this severe complication are late and thus delay correct diagnosis. In our patient the critical situation was recognized only after hemodynamic measurements and echocardiography. Emergency pericardiocentesis was followed by a dramatic improvement. The cardinal features of this serious event and the preventive measures to be taken to avoid this situation after placement of a central venous line are discussed.

Cardiac Tamponade↗
PubMed1987

Beta-adrenergic blockade and intravenous nutrient-induced thermogenesis in lean and obese women.

Continuous respiratory exchange measurements were performed in nine obese and eight lean women for 1 h before, 3 h during, and 1 h after the intravenous administration of a nutrient mixture infused at twice the postabsorptive resting energy expenditure (REE). This experiment was conducted without or with beta-adrenergic blockade (iv propranolol). Propranolol administration did not change the postabsorptive REE [i.e., 1.03 +/- 0.07 before vs. 1.01 +/- 0.02 kcal/min after administration in lean women and 1.16 +/- 0.04 vs. 1.15 +/- 0.03 kcal/min (NS) in obese women]. The mean overall thermogenic response expressed as a percentage of the infused energy was similar in both groups and was not significantly blunted after propranolol infusion [6.9 +/- 0.4 vs. 5.9 +/- 0.6% in the lean women and 7.5 +/- 0.5 vs. 7.1 +/- 0.6% (NS) in the obese women]. During beta-adrenergic blockade the rate of lipid oxidation decreased in the lean group but was unchanged in the obese group and the glycemic response to nutrient administration was significantly higher in both groups than without propranolol. It is concluded that beta-adrenergic blockade has no effect on REE and on intravenous nutrient-induced thermogenesis in both lean and obese women.

Adrenergic alpha-Antagonists↗
PubMed1986

[Spinal subarachnoid hemorrhage. Apropos of 2 cases of cauda equina tumors].

2 cases of spinal subarachnoid hemorrhage due to tumors of the cauda equina are reported. In both cases the existence of cephalic meningeal signs first suggested an intracranial pathology and diagnostic procedures were performed in this direction. Only when these examinations were negative was a lesion of the cauda equina suspected. The lesion was located by myelogram and was diagnosed, after surgical removal, as a schwannoma and an ependymoma. The syndrome of spinal subarachnoid hemorrhage involves spinal symptoms and signs resembling violent lumbar and radicular pain with a hemorrhagic cerebrospinal fluid, in association with symptoms of intracranial origin such as headache and meningism. Lumbar and radicular pain preceding the headaches, and an unaltered level of consciousness, point to the rare syndrome of spinal subarachnoid hemorrhage.

Adult↗