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Biomedical subjects

H A Wilkinson

Publications and source records attributed to H A Wilkinson.

At least 55 records · Page 3Linked to original sources
PubMed1986

Inherent dangers of simultaneous application of microfibrillar collagen hemostat and blood-saving devices.

Microfibrillar collagen hemostat is a topically applicable hemostatic agent that has been introduced relatively recently. Because of the possibility that this substance may pass through different blood-collecting circuits and cause organ damage if reintroduced into the patient's circulation, we performed a series of in vitro and in vivo experiments. The results of these experiments suggest that such a passage may indeed occur and could cause organ damage, either by direct or by induced embolization that cannot be completely prevented even with the application of commercially used filters. We therefore recommend that the substance should not be used if the shed blood is intended to be collected and returned into the patient's circulation.

Animals↗
PubMed1985

Stabilization of acrylic vertebral body replacement.

A simple technique of internal vertebral body screw fixation for stabilization of acrylic vertebral body replacements is described. The screw fixation prevents subluxation and rostrocaudal dislocation of the acrylic prosthesis. A case report is presented of a patient who underwent replacement of the second cervical body and odontoid with an intraoperatively molded methylmethacrylate prosthesis with rapid neurological recovery and good stabilization.

Acrylic Resins↗
PubMed1984

Percutaneous radiofrequency upper thoracic sympathectomy: a new technique.

The author describes a new technique for performing unilateral or bilateral upper thoracic sympathectomy safely, effectively, and more easily than by any of the surgical methods now in use. The technique described is one of percutaneous radiofrequency sympathectomy, which is usually done on a day surgery or outpatient surgery basis. The technique has been effective and well tolerated in a small group of patients.

Adolescent↗
PubMed1983

Furosemide and mannitol in the treatment of acute experimental intracranial hypertension.

Intracranial hypertension was induced in dogs and a small number of baboons by the inflation of epidural balloons. The resulting increased intracranial pressure (ICP) was treated with standard clinical doses of furosemide (0.7 mg/kg), "mini" doses of mannitol (0.75 g/kg), or both agents in combination. Mannitol consistently and rapidly reduced ICP in all animals. When results were averaged, furosemide used alone caused a slow reduction in ICP, but the results were variable in individual animals--with ICP actually increased in some. When furosemide and mannitol were given together, the ICP fell rapidly and remained low for considerably longer than after either agent alone.

Animals↗
PubMed1981

The linearity of the volume/pressure response during intracranial pressure "reserve" testing.

The intracranial pressure "reserve" test seems to be the most reliable method of determining when the brain's natural mechanisms for pressure compensation for added intracranial volume have been compromised or exhausted. The test employs a timed sequence of intracranial fluid injections, but as a safety precaution injections are discontinued if intracranial pressure remains elevated more than 10 Torr over baseline. In this case, a linear extrapolation is then calculated to determine the elevation which might have been achieved by a full series of injections. However, this linear extrapolation has been criticised on the expectation that an exponential response should be expected. A series of experimental observations in dogs and baboons and a review of clinical records in humans have been made to determine the observed slope of increase following aliquot injection during performance of the intracranial pressure reserve test. In these species the observed response was actually linear in shape rather than exponential. This held true even for different initial baseline values and with different volumes of "lesion" balloon inflations in experimental animals. A theoretic explanation is proposed.

Animals↗
PubMed1981

Gelfoam paste in experimental laminectomy and cranial trephination: hemostasis and bone healing.

The hemostatic properties and effect on osteogenesis of gelatin foam paste and bone wax were compared on surgical bone lesions in experimental animals. Thirty rabbits each received four trephine craniotomies and four lumbar laminectomies. Alternate bone incisions in each animal were treated with either gelatin foam paste or bone wax. Blood loss was measured by absorbing the blood into dry surgical cottonoids weighed before and after use. Bone healing sites of three rabbits were examined histologically to assess the effect of each agent on osteogenesis. The trephination sites of eight rabbits were subjected to fracture force testing at 6 weeks postoperatively to compare the effect ot the two agents on bone healing. No significant difference was found between gelatin foam paste and bone wax in either effectiveness of hemostasis or effect on osteogenesis.

Animals↗
PubMed1980

Lumbosacral meningismus complicating subdural injection of "blood patch": case report.

The published literature suggests that the technique of epidural "blood patch" injection is both safe and effective for the treatment and prevention of headache after spinal puncture. However, a case is reported in which the complications following a "blood patch" outweighed the disability and discomfort produced by the headache itself. The etiology is believed to have been inadvertent injection of blood into the subarachnoid space.

Adult↗
PubMed1979

Results of surgical lysis of lumbar adhesive arachnoiditis.

From a series of 681 patients with lumbar disc disease treated between 1966 and 1978, 17 patients required surgical lysis of lumbar adhesive arachnoiditis, 8 having initially been operated upon by another surgeon. All patients had severe pain as a predominant feature, with pain being bilateral in 9 patients. Pain was the only major symptom in 3; the other 14 exhibited varying combinations of progressive neurological dysfunction. Three patients developed late symptoms after trauma, 8 to 21 years after back surgery. At operation, multisegmental arachnoiditis was found in 5 patients and anular or subtotal adhesions were found in 12. Complete lysis could not be obtained in 4 patients. Fourteen patients were treated with steroids at the time of operation. Follow-up after lysis was less than 1 year for 5 patients but averaged 4.8 years for the remaining 12. During the 1st year after operation, 76% experienced improvement in pain (35%, good to excellent), 71% experienced improvement in neurological status. Follow-up after at least 1 year revealed 50% still enjoying pain relief (25%, good to excellent) and 45% experiencing neurological improvement. Pain relief persisted in 4 of 5 patients followed 5 years or more. The etiological role of myelograpy and lumbar disc surgery in arachnoiditis has probably been over-rated. Arachnoiditis may be symptomatic or asymptomatic and may mask other, treatable lumbar lesions. More frequent intradural exploration for discrepancies between operative and myelographic findings might reveal, and benefit, more cases of spontaneous arachnoiditis mimicking lumbar disc disease.

Adult↗
PubMed1979

Nonvolumetric methods of detecting impaired intracranial compliance or reactivity: pulse width and wave form analysis.

The authors have attempted to find a clinically reliable method of measuring intracranial pressure (ICP) compliance or reactivity that does not require volumetric manipulation. An analysis was undertaken of ICP, pulse widths and of the presence or absence of B waves, both experimentally in dogs and clinically in postoperative human patients. In both dogs and humans, ICP pulse width generally increased with increasing ICP and with increasing intracranial mass, and definitely increased with systolic arterial blood pressure. Nonetheless, ICP pulse width commonly failed to increase with increasing cerebral reactivity, and low ICP pulse width measurements were at times recorded in distinctly pathological situations. From the clinical study it was found that B waves were encountered more commonly in patients with increased ICP or increased ICP pulse width. However, the correlation between B waves alone or in combination with increased ICP or ICP pulse width and quantitative measurements of ICP reactivity was not significant. Mean reactivity and the range of reactivity measurements were almost identical in patient groups with and without B waves. For the time being the "ICP reserve test" remains the most accurate, the safest, and the most clinically useful method of quantitating ICP reserve.

Animals↗
PubMed1978

Intracranial pressure reserve testing. A study in experimental animals.

Quantitating cerebral "elastance" or "ICP reserve" has added considerably to the value of continuous monitoring of intracranial pressure (ICP). Intracranial pressure reserve is a measure of the capacity of the brain's natural compensatory mechanisms for countering increases in ICP secondary to increases in intracranial volume. Intracranial pressure reserve testing was studied in dogs with known volumes of extracerebral intracranial mass, both in normal and in edematous brains and at various ICPs. Ten thousand measurements were made with five different methods of measuring ICP reserve. Testing when multiple increments of subdural saline infusion were used over a five-minute period to quantitate ICP reactivity to volumetric stress seemed most reliable and most adaptable to clinical application. Methods of measuring cerebral "elastance" using only a single subdural infusion proved to be variable and difficult to read.

Animals↗