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Biomedical subjects

M H Lavyne

Publications and source records attributed to M H Lavyne.

16 recordsLinked to original sources
PubMed1992

Epidural steroids, postoperative morbidity, and recovery in patients undergoing microsurgical lumbar discectomy.

Intraoperative epidural corticosteroids have been used by some surgeons to decrease pain following surgery for a herniated lumbar disc. In this study, 84 consecutively treated, comparable patients with unilateral lumbar disc herniation were prospectively assigned randomly to receive either epidural corticosteroids (40 mg methylprednisolone acetate) or saline at the conclusion of the operative procedure. The postoperative morbidity of these two groups was evaluated by tabulating the following parameters: pain relief as measured by consumption of postoperative pain medications; the length of hospital stay; postoperative functional status; and the time interval from surgery until return to work. The mean postoperative analgesic medications consumed was 12.2 +/- 1.9 mg of morphine equivalents in the corticosteroid group versus 12.2 +/- 1.8 mg of morphine equivalents in the control group. The mean hospital stay was less than 2 days in each group, and the mean interval until return to work was 21.2 +/- 2.7 days in the corticosteroid group versus 25.4 +/- 3.1 days in the control group. Moreover, no statistically significant difference was measured between the steroid-treated and control groups when the data were stratified for sex, age, and site of disc herniation. The mean outcome scores, which are derived from a postoperative assessment of pain relief resulting from surgery, functional status, and interval until return to work, were identical in the corticosteroid and control groups. This study concludes that epidural corticosteroid administration after microsurgical lumbar discectomy for unilateral disc herniation does not lessen postoperative morbidity or improve functional recovery.

Adolescent↗
PubMed1990

Is magnetic resonance imaging useful in guiding the operative approach to large pituitary tumors?

Forty-two patients with large pituitary tumors were studied with magnetic resonance imaging scans. Based on the operative findings, the tumors were divided into two groups. Tumors in Group 1 (n = 35) were soft or partially necrotic and were easily removed by suction and curettage. Tumors in Group 2 (n = 7) were firm and required sharp dissection or use of the laser for removal. Tumors were divided into two groups based on the long TR signal: a) isointense in comparison with white matter, or b) hyperintense in comparison with white matter. All 7 firm tumors (Group 2) had an isointense signal on long TR sequences. Thirty-two of 35 soft tumors showed a hyperintense signal on long TR sequences, and 3 an isointense signal. Based on these results, we recommend a transsphenoidal approach for the initial operation in patients with large pituitary tumors. If the tumor is largely isointense on the magnetic resonance imaging scan, we discuss with the patient preoperatively the possibility (70% in this series) that the tumor may be too firm to remove in a single transsphenoidal procedure. In these circumstances, a second, transcranial, procedure may be required to decompress the suprasellar structures adequately.

Adenoma↗
PubMed1990

Retrospective analysis of microsurgical and standard lumbar discectomy.

This report retrospectively evaluates 112 cases of microsurgical lumbar discectomy (MICRO) and 35 cases of standard discectomy (STND) performed by one neurosurgeon using data derived from a questionnaire and from chart review. The total amount of postoperative pain medication consumed and postoperative temperature curves in each group were compared to determine how postsurgical morbidity was affected by the MICRO and STND procedures. At a mean follow-up interval of 12.3 and 41 months, 97% of the MICRO respondents reported a good or excellent outcome. Patients with preoperative symptoms exceeding 6 months returned to work in 9.9 +/- 1.7 weeks; this interval decreased to 5.58 +/- 0.75 weeks, and overall outcome score improved significantly at 41 months' follow-up if symptoms were less than or equal to 6 months in duration before surgery. At 44 months' mean follow-up, 88% of the STND respondents reported a good or excellent outcome with no decrease in the return-to-work interval in patients who described symptoms of 6 months or less. Mean postoperative pain medication consumed by MICRO patients was one tenth that of STND patients, and temperature curves showed significant temperature elevations in the STND group when compared with the MICRO group, in which patients remained afebrile throughout the postoperative period. Within the limitations of a retrospective study, these data support the conclusion that a microsurgical approach to the lumbar herniated disc provides a more frequent and rapid convalescence than the STND approach.

Adult↗
PubMed1979

Clinical and radiologic remission in reticulum cell sarcoma of the brain.

Two patients with cerebral reticulum cell sarcoma (CRCS) are reported in whom neurologic abnormalities and radiologic (computerized tomographic [CT] scan) evidence of tumor remitted. In one patient, remission followed craniectomy and corticosteroid therapy and lasted for eight months. In the other patient, at least four remissions occurred over a span of seven years, each in conjunction with the administration of corticosteroids. Corticosteroids may favorably alter the biologic activity of tumor tissue in some cases of CRCS, predisposing to clinical remission and disappearance of tumor on CT scan.

Adult↗
PubMed1978

Localization of vertex lesions seen on CT scan.

A simple method is presented for localizing the anatomical site of vertex lesions seen on a computerized tomography (CT) brain scan, using the patient's plain lateral skull film.

Brain Neoplasms↗
PubMed1977

Decrease in neostriatal blood flow after D-amphetamine administration or electrical stimulation of the substantia nigra.

Local blood flow was measured in the caudate nuclei and, in some cases, other areas of rat and monkey brain by the hydrogen clearance technique. Resting values for caudate blood flow in the rat were similar to those reported elsewhere, i.e., 69 +/- 4 ml/min/100 g in the caudate. Administering D-amphetamine sulfate (0.5 mg/kg, i.p.) to rats reduced caudate flow by a maximum of about 33% after 30 min; this effect could be blocked by pretreatment with haloperidol (5.0 mg/kg, i.p.), a drug that blocks dopamine receptors. D-Amphetamine sulfate (1.5 mg/kg) also reduced caudate but not cortical blood flow in unanesthetized monkeys. Electrical stimulation of the pars compacta of the substantia nigra reduced ipsilateral caudate flow by about 25% without affecting flow in the contralateral caudate. This effect varied with the frequency and intensity of stimulation. These studies suggest that the intraparenchymal release of brain dopamine may modify intraparenchymal (local) blood flow.

Animals↗
PubMed1976

Reversal of experimental cerebral vasospasm by intravenous nitroprusside therapy.

Cerebral vasospasm was induced in dogs by intracisternal injection of blood. After angiographic demonstration of spasm, sodium nitroprusside was infused intravenously and its effect on the diameter of the basilar artery was studied angiographically. Ten experiments were performed within 90 minutes of the induction of spasm and nine experiments were performed 24 or 48 hours later. Significant dilatation of the basilar artery was achieved in all cases and it persisted for as long as the infusion of nitroprusside continued. The drug produced a modest degree of systemic hypotension. In six experiments it was possible to avoid hypotension by a simultaneous infusion of dopamine.

Animals↗
PubMed1975

Brain H-3-catecholamine metabolism in experimental cerebral ischemia.

Unilateral ligation of a common carotid artery in gerbils causes a major depletion of brain dopamine, which is most marked in brain regions known to receive dopaminergic projections. To determine whether this depletion reflects release of stored dopamine, a radioactive label (H-3-dopamine) was introduced into brain dopamine pools 4 hours prior to ligation. Twenty-four hours later, brain H-3-catecholamines were profoundly depressed ipsilateral to the lesion among animals exhibiting clinical signs of stroke. Within brain regions known to receive dopaminergic projections, common carotid ligation also was associated with a selective decrease in the concentration of H-3-deaminated metabolites. These data suggest that cerebral ischemia is associated with release of catecholamines, as well as with impaired oxidative metabolism of catecholamines.

Animals↗
PubMedDate not supplied

Limitations of diazoxide reversal of vasospasm.

Diazoxide failed to safely relieve cerebral vasospasm by intracisternal injections in dogs and by intracarotid injections in monkeys despite in vitro documentation of arterial relaxation with this agent. Administration of the drug frequently produced hypotension and, in the presence of vasospasm, was associated with a high mortality rate.

Animals↗
PubMedDate not supplied

Effect of intravenous sodium nitroprusside on cerebral blood flow and intracranial pressure.

Local cerebral blood flow was measured with the hydrogen clearance technique during intravenous infusion of nitroprusside in monkeys. Concentrations of the drug required to reduce the mean arterial blood pressure by less than 40% resulted in no significant change or only a slight increase in regional cerebral blood flow. Larger doses, however, produced a loss of cerebral autoregulation, thereby inducing a drop in cerebral blood flow. Intracranial pressure rose proportionately to the nitroprusside dose during the infusion.

Animals↗
PubMedDate not supplied

Giant intracranial aneurysms of the anterior circulation: clinical characteristics and diagnosis by computed tomography.

The computed tomography (CT) characteristics and clinical features of giant (globoid) aneurysms of the anterior circulation are reviewed. These lesions appear on the CT scan as smoothly encapsulated ovoid masses, within which a partially patent lumen is seen after the infusion of iodinated contrast material. With careful analysis of the CT scan it may be possible to differentiate giant internal carotid artery, anterior cerebral artery, and middle cerebral artery aneurysms from other parasellar and hemispheric lesions.

Adult↗