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Biomedical subjects

K Wester

Publications and source records attributed to K Wester.

At least 55 records · Page 3Linked to original sources

CT guided stereotaxy based on scout view imaging.

A simple and inexpensive method for CT guided stereotaxy is described. The method requires no extra equipment in the interface between the computer tomograph and the stereotaxic frame, and could therefore easily be adopted in most neurosurgical units. With this method, information from the transaxial CT sections is transferred manually via the scout view image to the operation theater skull x-rays, and thereby to the stereotaxic frame. The method has proved to be sufficiently accurate for all current non-functional stereotaxic procedures in our department during 30 months of testing.

Brain

Dorsal column stimulation in pain treatment.

Thirty-five patients with chronic pain were treated by electrical stimulation of the dorsal columns through implanted epidural electrodes. In 5, such stimulation had minimal pain-reducing effect during an immediate postoperative trial period, and the electrodes were removed. In the remaining 30, an electrode system for chronic stimulation was implanted. Four of these died of related or unrelated causes. The electrode system was removed in 2 patients due to infections, and in 1 due to mechanical discomfort. The remaining 23 patients answered a questionnaire concerning the pain reducing effect of stimulation (4-60 months postoperatively, median 15 months). The group as a whole estimated the pain reducing effect of stimulation as weak. Only 10 patients (43.5%) used the stimulator regularly. Even in these patients, the pain-reducing effect was limited. Chronic back pain after repeated back surgery responded relatively better to stimulation than did the other cases. Phantom limb pain was most resistant. The modest results suggest future restriction on the use of such stimulation.

Anesthesia, Local

A simple and inexpensive method for CT-guided stereotaxy.

A simple and inexpensive method for CT-guided stereotaxy is described. The method requires neither sophisticated computer programs nor additional stereotactic equipment, such as special head holders for the CT, and can be easily obtained without technical assistance. The method is designed to yield the vertical coordinates.

Humans

Long-lasting facilitation of a synaptic potential following tetanization in the in vitro hippocampal slice.

Field potentials evoked by stimulation of afferent fibers in stratum radiatum were recorded in the CA1 region of the hippocampal slice maintained in vitro. Stimulation rates of 3-50/sec produced a large increase in amplitude of the population spike in CA1. This increase was maintained for several hours after the tetanization. The facilitation phenomenon appeared to be specific to the synapse of stratum radiatum afferents onto CA1 pyramidal cells since: (1) stimulation outside the radiatum layer did not produce the effect, (2) antidromic field potentials recorded in CA3 were unchanged, (3) EPSP threshold in CA1 was unchanged, and (4) alveus tetanization did not produce a facilitatory effect.

Animals