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Biomedical subjects

F H Sklar

Publications and source records attributed to F H Sklar.

24 records · Page 2Linked to original sources

The influence of thin-section tomography on the treatment of cervical spine injuries.

A study was performed to determine the influence of routine thin-section tomography on subsequent treatment of the patient with acute trauma to the cervical spine. Of 79 such patients who underwent tomography over a 14-month period, 55 had suspicious indirect findings on the radiograph and 25% of these were shown to have fractures, while 67% of the patients without radiographic abnormalities who presented with a neurological deficit also demonstrated fractures on tomography. Of the patients who were shown to have fractures prior to tomography, 54% had more extensive injury than originally suspected. In nearly 18% of patients, the mode of therapy was changed significantly after tomographic evaluation. Indications for tomography are discussed and specific recommendations for systematic radiographic evaluation of cervical spine injuries are presented.

Adolescent↗

The pressure-volume function of brain elasticity. Physiological considerations and clinical applications.

The intracranial pressure-volume function as determined by brain elasticity is reported in normal dogs. Rapid subarachnoid infusions clearly define an exponential relationship between pressure and volume. An aliquot technique to measure elastance (dP/dV) at multiple intracranial pressures demonstrates a linear relationship between elastance and pressure. This follows mathematically from the exponential nature of the basic pressure-volume function. The clinical significance of brain elastance measurements is discussed. It is emphasized that the effects of pressure on CSF dynamics are superimposed on the pressure-volume function of brain elasticity and probably account for the process of spatial compensation for an expanding mass lesion. It is not apparent that elastance measurements can serve as indicators of impending decompensation, since the pressure-volume function of brain elasticity provides no direct information about CSF dynamics. Accordingly, the clinical usefullness of elastance measurements is seriously questioned.

Animals↗

Recirculatory spinal subarachnoid perfusions in dogs: a method for determining CSF dynamics under non-steady state conditions.

Open-ended ventriculocisternal perfusion techniques for determining cerebrospinal fluid production and absorption rates are severely restricted by the absolute requirement that steady state conditions be present. A new closed recirculatory spinal perfusion technique is described. Because steady state equilibrium is not necessary, numerous determinations at multiple intracranial pressures or under varied experimental conditions are possible within relatively brief perfusion periods. Cerebrospinal fluid (CSF) and nondiffusible albumin tracer are rapidly recirculated through the spinal subarachnoid space in a cephalad direction. The concentration of fluorescein-tagged albumin is continuously monitored as the CSF is circulated through a fluorometric flow cell. Measured continuously, intracranial pressure (ICP) is regulated by changing the volume of the external perfusion circuit with a syringe pump connected in series to the recirculatory spinal perfusion. CSF formation and absorption rates are calculated from measurements of albumin concentration, concentration changes with time, ICP, syringe pump infusion rate, and the external perfusion circuit volume. In dogs, data can be collected after only 45 minutes for mixing; perfusions at four or five intracranial pressures in addition to normal resting pressure can be completed within 2 to 3 hours. The data from 15 perfusions in 14 dogs are presented. The method provides normal resting pressure values of CSF production and absorption consistent with those values in the literature determined by traditional ventriculocisternal perfusion techniques. Determinations at multiple intracranial pressures suggest a proportional relationship between absorption and ICP. No consistent acute change in CSF formation with pressures to 50 mm Hg can be inferred from these data.

Animals↗

Servo-controlled lumbar infusions: a clinical tool for the determination of CSF dynamics as a function of pressure.

The variable rate lumbar subarachnoid infusion technique allows rapid quantitative study of the cerebrospinal fluid (CSF) compartment. Numerous pressure plateaus are studied in a brief time period with a servo-controlled system. The test determines the difference between rates of CSF absorption and formation as a function of pressure. On-line computer data analysis increases experimental efficiency to guarantee statistical significance. Animal and patient data are presented in the report.

Absorption↗