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Biomedical subjects

D Louw

Publications and source records attributed to D Louw.

15 recordsLinked to original sources
PubMed2001

A modified technique to treat subdural hematomas: the subdural evacuating port system.

BACKGROUND: The Subdural Evacuating Port System (SEPS) is intended for drainage of subdural fluid collections such as hygromas and hematomas. Unlike other subdural fluid drainage systems, no drain is placed in the subdural space. This paper describes the technique and reports our experience thus far. METHODS: We treated 20 patients for 22 subdural hematomas. One or two ports were inserted for drainage of each subdural collection. Follow-up ranged from six to 24 months. RESULTS: Follow-up CT obtained at approximately one month postprocedure showed complete or near complete resolution of 18 of the subdural collections. Failure of the SEPS was noted in four patients and was related to plugging of the drainage system by clots secondary to the presence of fresh blood in the subdural collection. CONCLUSIONS: The Subdural Evacuating Port System (SEPS) permits the neurosurgeon to drain subacute or chronic hematomas by a method which is minimally invasive, simple and safe.

Aged↗
PubMed2000

Reliability in grading the severity of lumbar spinal stenosis.

Stenosis of the lumbar spinal canal is a major cause of disability and lost productivity. Computed tomography (CT) is used commonly to assess the presence and severity of spinal stensosis, because it is relatively inexpensive, readily available, and has few adverse effects. The ability of four surgeons to agree about the presence and severity of lumbar spinal stenosis based on plain CT scans was evaluated from 30 scans of varying stenosis severity (normal to severe). Kappa, a measure of chance-corrected agreement, was calculated. Surgeons exhibited moderate agreement for the presence or absence of spinal stenosis (kappa = 0.58+/-0.06). Agreement regarding the severity of stenosis, when present, was poor (kappa = 0.26+/-0.04). The ability of surgeons to agree was not improved when individual features of the CT scans were assessed (facet joint arthrosis, ligamentum flavum hypertrophy, disk protrusion, and nerve root impingement). This study suggests that CT scans are not a reliable method by which to examine the severity of lumbar spinal stenosis.

Humans↗
PubMed1999

A mobile high-field magnetic resonance system for neurosurgery.

OBJECT: The authors' goal was to place a mobile, 1.5-tesla magnetic resonance (MR) imaging system into a neurosurgical operating room without adversely affecting established neurosurgical management. The system would help to plan accurate surgical corridors, confirm the accomplishment of operative objectives, and detect acute complications such as hemorrhage or ischemia. METHODS: The authors used an actively shielded 1.5-tesla magnet, together with 15 mtesla/m gradients, MR console computers, gradient amplifiers, a titanium, hydraulic-controlled operating table, and a radiofrequency coil that can be disassembled. The magnet is moved to and from the surgical field by using overhead crane technology. To date, the system has provided unfettered access in 46 neurosurgical patients. In all patients, high-definition T1- and/or T2-weighted images were rapidly and reproducibly acquired at various stages of the surgical procedures. Eleven patients underwent craniotomy that was optimized after preincision imaging. In four patients who harbored subtotally resected tumor, intraoperative MR imaging aided the surgeon in removing the remaining tumor. Interestingly, the intraoperative administration of gadolinium demonstrated a dynamic expansion of enhancement beyond the preoperative contrast contour in patients with malignant glioma. These zones of new enhancement proved, on examination of biopsy samples, to be tumor. CONCLUSIONS: The authors have demonstrated that high-quality MR images can be obtained in the operating room within reasonable time constraints. Procedures can be conducted without compromising or altering traditional neurosurgical, nursing, or anesthetic techniques. It is feasible that within the next decade intraoperative MR imaging may become the standard of care in neurosurgery.

Adult↗
PubMed1999

Predictors of return to work after anterior cervical discectomy.

Return to previous level of employment after surgery is important to patients. Predictors of return to work have been well described in lumbar disc surgery. However, this information cannot be generalized to the population undergoing cervical discectomy. The authors retrospectively reviewed 67 consecutive patients who underwent anterior cervical discectomy. Strict inclusion criteria were used. Baseline demographics were recorded as well as other potential predictors of postoperative return to work such as number of levels of disease, smoking history, and disability claims. Follow-up information about work status was reviewed with each patient at office visit. Forty-five patients were found eligible for the study. At a mean follow-up of 2.8 years (SD 1.4), 38% had not returned to work by 1 year. Preoperative sick leave in this group was significantly greater than for those patients who returned to work within the year (p = 0.0014). Postoperative neck pain was more common in individuals who did not return to work after surgery (p = 0.01). Increasing age and disability claims also appeared to negatively impact the ability to return to work. Gender, type of work, smoking history, and number of levels of disc disease did not appear to have any association with postoperative return to work. The authors conclude that the duration preoperative sick leave and postoperative neck pain negatively impact postoperative work status in patients undergoing anterior cervical discectomy. Age and disability claims also influence return to work.

Adult↗
PubMed1998

Pitfalls of bungee jumping. Case report and review of the literature.

A case of cervical spine injury related to bungee jumping is presented. Surgical intervention resulted in resolution of the patient's quadriparesis. The incidence of serious injury connected with this pastime is not inconsiderable, and it is recommended that safer jumping practices be followed. Inspection of bungee equipment and certification of instructors is now voluntary but should be mandated. Jumping heights should be limited and the use of air cushions encouraged.

Adult↗
PubMed1996

Initial stabilization and medical management of acute spinal cord injury.

Despite intensive preventive efforts, acute spinal cord injury remains a significant public health problem. The pathophysiology of this type of injury involves both the primary, or initial, mechanical injury and secondary injury mechanisms such as ischemia, lipid peroxidation and intracellular calcium influx. Initial management includes immobilization of the injured spine, maintenance of the airway, systemic oxygen delivery and treatment of neurogenic shock. All patients with acute spinal cord injury should receive an intravenous bolus of methylprednisolone, 30 mg per kg, within eight hours of injury, followed by an infusion of 5.4 mg per kg per hour for 23 hours. Transfer to a regional acute spinal cord injury unit for definitive management should be accomplished as soon as the patient's condition is stabilized.

Acute Disease↗
PubMed1991

Global elevation of brain superoxide dismutase activity following forebrain ischemia in rat.

Regional superoxide dismutase (SOD) activity and lipid peroxidation (as reflected by thiobarbituric acid-reactive substances (TBARS)) have been measured at increasing post-ischemic time intervals following a (10 min) forebrain ischemic insult in rat. All brain regions showed significant progressive increases in SOD activity with increasing post-ischemic time intervals. Lipid peroxidation also was significantly increased in frontal and parietal/occipital regions at 1 and 24 h post-ischemia, although this was several orders of magnitude less than the increase in SOD activity. By 7 days post-ischemia lipid peroxidation had returned to control values for all regions. These data are consistent with the hypothesis that cerebral ischemia is accompanied by glial activation with an associated increase in SOD activity. Global increases in SOD activity may protect the brain from free radicals, thereby preventing large increases in lipid peroxidation.

Animals↗
PubMed1990

Meningiomas mimicking cerebral schwannoma.

A brain tumor with histological features reminiscent of schwannoma with underlying meningioangiomatosis was subjected to electron microscopic and immunohistochemical analysis, which confirmed the neoplasm as a meningioma. This prompted reexamination of a similar tumor, described in a previous publication as a cerebral schwannoma, with identical immunohistochemical techniques. The results obtained favored alteration of this diagnosis to that of meningioma. This experience has led the authors to recommend the use of immunohistochemistry techniques when evaluating unusual intracranial neoplasms.

Adolescent↗
PubMed1989

A study of monoamine metabolism in human epilepsy.

Fourteen patients with intractable epilepsy underwent surgical resection of their epileptogenic focus. Hippocampal and temporal cortical samples were obtained, and subjected to high performance liquid chromatography with electrochemical detection. Levels of 5-hydroxyindoleacetic acid (5-HIAA) in actively spiking temporal cortex were 0.454 +/- 0.012 ng/mg (mean +/- SEM), contrasting with less actively spiking cortex values of 0.248 +/- 0.042 ng/mg and normal literature values, obtained from post-mortem material, of 0.140 +/- 0.050 ng/mg. Similarly, homovanillic acid (NVA) levels were significantly increased in epileptic tissue compared to normal literature values. Actively spiking cortex values were 0.172 +/- 0.001 pg/mg, less active cortex values were 0.058 +/- 0.012 pg/mg, and literature values were 0.011 +/- 0.002 pg/mg. Although a direct statistical comparison between the data reported here and literature values may not be valid, the findings show a continuum from normal through increasingly active electrode sites, likely reflecting a true biologic phenomena. Similarly, statistically significant increases in 5-HIAA and HVA levels were found in hippocampal tissue, which also showed significantly lower dihydroxyphenylacetic acid levels. We conclude that raised levels of serotonin and dopamine metabolites in actively spiking cortex likely reflect an increase in their turnover, and are an epileptic epiphenomenon. Exaggeration of turnover may represent the "metabolic noise" of epilepsy, rather than a concerted strategy of local or distal neurons to contain an epileptogenic focus.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1989

Effect of lidocaine on forebrain ischemia in rats.

We examined the effect of lidocaine on ischemic neuronal injury in the rat forebrain ischemia model. Cerebral ischemia was achieved with bilateral carotid artery occlusion and controlled hypotension to a mean of 50 torr for 10 minutes. Perfusion-fixation was performed 7 days after ischemia, subsequent to which the brains were sectioned coronally and stained with hematoxylin and eosin. Ischemic neuronal injury was quantitatively expressed (after direct counting) as a percentage of total neurons, that is, ischemic neurons divided by (ischemic neurons + normal neurons). Predictably, the selectively vulnerable hippocampal areas exhibited the most marked neuronal injury. In the CA1/CA2 sectors, lidocaine-treated rats demonstrated less injury (34 +/- 14%) than untreated (64 +/- 9%) or saline-treated (70 +/- 10%) rats. However, these superficially pronounced numerical differences were not of statistical significance (p greater than 0.05). In the CA3 sector, neuronal injury in lidocaine-treated rats (31 +/- 14%) was significantly different at p less than 0.05 from the untreated (80 +/- 5%) but not the saline-treated (59 +/- 13%) group. We conclude that lidocaine may have an only marginal beneficial effect on forebrain ischemia in rats.

Animals↗
PubMed1987

Epidemiology of primary intracranial neoplasms in Manitoba, Canada.

The incidence of primary intracranial tumors in Manitoba, Canada was reviewed. From 1980 through 1985, 657 tumors were diagnosed. The crude incidence rates were 10.2/100,000 for males and 10.8/100,000 for females. The three most common tumors were: astrocytoma 281 (43%), meningioma 145 (22%), and pituitary adenoma 111 (17%). Average annual incidence rates for all tumors showed a bimodal distribution with one peak in the 0-4 age group (4.2/100,000), and the other in the 60-69 age group (27.2/100,000). For malignant astrocytoma, the age-specific annual incidence rate increased to the seventh decade where it reached a peak of 14.3/100,000. The incidence of benign astrocytoma remained relatively constant with age at 1.1/100,000. The annual incidence of meningioma increased with age up to the eighth decade reaching 7.2/100,000. Of the 145 meningiomas, 56 (39%) were meningotheliomatous, 48 (33%) transitional, 10 (7%) malignant, 7 (5%) fibroblastic, 6 (4%) psammomatous, 3 (2%) angioblastic, and 15 (10%) lacked pathologic diagnosis. The annual incidence of pituitary adenoma showed two peaks, the first occurring in the third decade (2.6/100,000) and the second in the eighth decade (3.2/100,000). Although the incidence of meningioma was relatively high, the clinical features and pathologic patterns of these tumors were not unlike those previously reported in the literature.

Adolescent↗
PubMed1976

Geriatric care: where does the responsibility lie?

In contrast to purposeful efforts in South Africa to lay sound foundations for the development of social services for the aged, little constructive planning has been done by medical authorities to provide for the special health needs of the elderly on a national basis and based on recognised geriatric principles.

Attitude of Health Personnel↗