Search PubMed⌕ Search

Biomedical subjects

D P Becker

Publications and source records attributed to D P Becker.

At least 199 records · Page 11Linked to original sources
PubMed1978

Microsurgical cerebral revascularization for the treatment of stroke.

A study of 1,000 STA-MCA by-pass procedures in stroke patients is described as "extremely encouraging", with greater than 90% patency rate and marked improvement in patients who had not responded to medical management or had been turned away from routine vascular surgery.

Cerebral Arteries↗
PubMed1977

Evaluation of brain function in severe human head trauma with multimodality evoked potentials. Part 1: Evoked brain-injury potentials, methods, and analysis.

Methods for obtaining multimodality evoked potentials, somatosensory, visual, auditory, and auditory brain-stem potentials in patients with severe head trauma are described. A method of analyzing abnormal multimodality evoked potentials (graded evoked brain-injury potentials) is proposed that defines the degree of abnormality of the electrophysiological data and expresses it simply in four grades per modality. Data from 20 normal subjects are given for comparison with the abnormal data obtained from 51 patients with head trauma.

Acoustic Stimulation↗
PubMed1977

The outcome from severe head injury with early diagnosis and intensive management.

In the belief that secondary cerebral compression, hypoxia, and ischemia materially influence the outcome from severe head injury, a standardized protocol was followed in 160 patients, with emphasis on early diagnosis and evacuation of intracranial mass lesions by craniotomy, artificial ventilation, control of increased intracranial pressure, and aggressive medical therapy. Of these patients, 36% made a good recovery, 24% were moderately disabled, 8% were severely disabled, 2% were vegetative, and 30% died. The mortality rate compares favorably with outcomes in similar patients reported from other centers and there has been no increase in the numbers of severely disabled or vegetative patients. It is proposed that vigorous surgical and medical therapy, by preventing or reversing secondary cerebral insults, enables some patients who would have died to make a good recovery without increasing the proportion of severely disabled patients.

Adolescent↗
PubMed1977

Significance of intracranial hypertension in severe head injury.

Measurements of intracranial pressure (ICP) were begun within hours of injury in 160 patients with severe brain trauma, and continued in the intensive care unit. Some degree of increased ICP (greater than 10 mm Hg) was present on admission in most cases (82%), and in all but two of the 62 patients with intracranial mass lesions requiring surgical decompression; ICP was over 20 mm Hg on admission in 44% of cases, and over 40 mm Hg in 10%. In patients with mass lesions only very high ICP (greater than 40 mm Hg) on admission was significantly associated with a poor neurological picture and outcome from injury, while in patients with diffuse brain injury any increase in ICP above 10 mm Hg was associated with a poorer neurological status and a worse outcome. Despite intensive measures aimed at prevention of intracranial hypertension, ICP rose over 20 mm Hg during the monitoring period in 64 of the 160 patients (40%). Postoperative increases in ICP over 20 mm Hg (mean) were seen in 52% of the patients who had had intracranial masses evacuated, and could not be controlled by therapy in half of these cases. Even in patients without mass lesions, ICP rose above 20 mm Hg in a third of the cases, despite artificial ventilation and steroid therapy. Of the 48 patients who died, severe intracranial hypertension was the primary cause of death in nearly half and even moderately increased ICP (greater than 20 mm Hg) was associated with higher morbidity in patients with mass lesions and those with diffuse brain injury. Measurement of ICP should be included in management of patients with severe head injury.

Brain Injuries↗
PubMed1977

The physiological basis of intracranial pressure change with progressive epidural brain compression. An experimental evaluation in cats.

Sequential cerebrospinal fluid (CSF) pressure-volume studies were carried out in seven cats during the expansion at a constant rate of an epidural balloon. The same studies were performed in three control cats. Beginning after 20 minutes of inflation and continuing to the point of pupillary dilatation there was a progressive increase in the pressure-volume index (volume required to change intracranial pressure (ICP) by tenfold). During the course of balloon inflation, there was also a progressive increase in CSF elastance (instantaneous ICP change per unit change in CSE volume). At the point of pupillary dilatation there was a marked, abrupt increase in the pressure-volume index and an equally dramatic decrease in CSF elastance. The CSF outflow resistance increased to a variable extent during balloon inflation. The plot of the CSF pressure versus balloon volume (the mass lesion pressure-volume curve) was of the classical configuration with an initial relatively flat segment and a final steep segment. A hypothesis is presented that interprets the shape of the mass lesion pressure-volume curve in terms of changes occurring in the elastic properties of the tissues surrounding the CSF space and the volume of the CSF space. It is proposed that this hypothesis will explain most of the commonly observed variations in CSF pressure. Confusion regarding the ICP-volume relationships has arisen because of lack of specificity regarding which anatomical spaces are being perturbed.

Animals↗
PubMed1976

ICP monitoring: complications and associated factors.

1. Patients with complications when compared with those not developing a complication: a. Were older, 44.4 vs. 34.5 years; b. Were monitored longer, 14.0 vs. 6.5 days; c. Were treated with steroids longer, 18.3 vs. 10.3 days; d. Were hospitalized longer, 35.7 vs. 27.7 days; e. Are twice as likely to die; f. Average age of those dying is older, 46 vs. 30 years; g. Have no clear relationship to antibiotics; h. Do not have a preponderance of single diagnostic category to account for these differences; i. Complications were always controlled with standard therapy; j. An ICP complication was almost never responsible, per se, for death. 2. Over all complication rate was 18%; due to monitoring was 4.5 to 11.5%. 3. Monitoring was responsible for, or contributed to, 25 to 60% of the complications. 4. No complications occurred when monitoring was discontinued within 3 days. 5. Long periods of treatment with steroids increased the risk of a complication developing. 6. Long periods of monitoring were associated with an increased risk of complication. 7. "Individual" factors are partly responsible for the development of a complication, and death. 8. There are two groups of complications: "early" and "late." A. Those most likely to be monitor related occur "late" and account for 35% of the complications. B. Those developing "early" infection account for 65% of the complications and are most likely caused by factors other than monitoring. While there are complications directly attributable to monitoring, the rate is low and they are readily controlled by standard neurosurgical management. While monitoring may increase the morbidity, it does not increase the mortality. We feel that the over-all risk is small and that the returns are great--both in terms of knowledge and patient benefit.

Adult↗
PubMed1976

Fluid-percussion model of mechanical brain injury in the cat.

Mechanical brain injury was produced in 36 cats with a fluid-percussion model in which brain damage or dysfunction is produced by a single, brief, hydraulically-induced pressure transient that is conducted through the brain. Fluid-percussion injury induce elastic deformation of the brain resembling the brain deformation known to occur following head impact. Physiological responses and pahtological changes following injury were expressed as a function of peak pressure. Macroscopic central nervous system lesions concentrated at the pontomesencephalic junction, cervicomedullary junction, and in the cerebellar tonsils were consistently observed at and above 2.6 atmospheres (atm). At higher levels of injury (greater than or equal to 3.2 atm) there was extensive basal subarachnoid hemorrhage. At very high levels of injury (greater than 4.0 atm) hemorrhagic contusions were noted at the cerebral hemisphere impact site. A spectrum of neuronal alterations was identified in the damaged areas. Computer analysis showed correlation of electroencephalographic (EEG) changes with the neuropathological changes, since EEG recovery became severely impaired above 2.6 atm. No EEG changes were noted below 1.5 atm. From 1.5 to 2.2 atm there was a physiological response to injury but no significant changes were seen on neuropathological examination. This range of injury should permit further studies of the more subtle changes following mechanical brain injury without intraparenchymal hemorrhage or subarachnoid hemorrhage. The fluid-percussion model relates brain deformation following mechanical loading to a single pressure transient that is easily measured and controlled. Further quantitative investigation into the pathobiology of mechanical brain injury following graded brain deformation is thus made possible.

Animals↗
PubMed1975

Acromegaly. Treatment by transsphenoidal microsurgery.

Serum growth hormone levels, thyroid function, and adrenal function were measured before and after surgery in 16 of 17 acromegalic patients undergoing undergoing transnasal transsphenoidal microsurgery of the pituitary. Thirteen patients have been followed up for 12 to 24 months; three patients have been followed up for three to six months. Serum growth hormone levels decreased to less than 5 ng/ml in seven of nine previously untreated patients; thyroid and adrenal function were preserved in eight of these nine patients. In seven patients treated previously by other modes of therapy, growth hormone levels after transsphenoidal surgery decreased to less than 5 ng/ml in three, to between 5 and 10 ng/ml in three, and from 98 to 41 ng/ml in one. Preoperative adrenal function was normal in six of these seven patients and was preserved in four; thyroid function was normal in five patients preoperatively and was preserved in three. Transsphenoidal microsurgery appears to offer an effective means of lowering growth hormone levels and a possiblity of preserving any remaining normal pituitary function. It may be considered for initial treatment in selected patients in whom more rapid arrest of acromegaly is indicated.

Acromegaly↗
PubMed1975

Threshold for pain from anterolateral quadrant stimulation as a predictor of success of percutaneous cordotomy for relief of pain.

A sensitive quantitative index for predicting optimal electrode position in percutaneous anterolateral cordotomy was determined by electrical stimulation through the lesioning electrode. If the threshold for pain elicited by the stimulation electrode was less than 300 muA, a 5-sec radiofrequency lesion of 50 mA would produce complete contralateral analgesia with no weakness. When the pain threshold exceeded 300 muA, incomplete or no analgesia would result with the standard single lesion. The results further suggested that the fibers in the anterolateral quadrant that transmit pain are discretely rather than diffusely localized.

Cordotomy↗