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Results for “Electrodes, Implanted”

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PubMedDate not supplied

Experience with implanted electrodes.

Implant units, manufactured by Medtronic, Inc., have been implanted in 31 patients for treatment of drop-foot. The principal problem encountered in this series was inflammatory reaction. This was observed in seven patients, and was serious enough in five to require removal of the implant. On the positive side, there have been no failures of the implanted equipment for periods of up to 7.3 years, although there is currently a question on one patient. There has also been no documented damage to the nerve from chronic stimulation. Fine wire elctrodes have been implanted intraneurally in a series of animals and in three patients. Preliminary results look encouraging, and this approach seems to hold considerable promise for a new generation of electrode design.

Amputees↗
PubMed1979

Effect of lactulose, neomycin and antacid on colonic pH recorded continuously with an implanted electrode.

Colonic pH was continuously monitored by a pH electrode implanted in the transverse colon of rats over a 24-hour period. Lactulose significantly reduced the colonic pH to 5.37 +/- .39 from a fasting value of 6.77 +/- .75. Pretreatment with neomycin or concomitant use of a nonabsorbable antacid prevented lactulose-induced reduction in the colonic pH. The clinical implication of the study is that combined use of lactulose with neomycin or high doses of non-absorbable antacids in the treatment of chronic portasystemic encephalopathy may be undesirable.

Animals↗
PubMed1979

Electrode implantation and electrostimulation in rabbits.

The investigators studied functional electrostimulation by means of an implanted electrode placed around the peroneal nerve in rabbits. Current pulses were administered from a stimulating unit outside the body, via a connecting skin plug and subcutaneous leads to the electrode. It is concluded that if this form of stimulation is to be praticable without undesirable results, certain mechanical problems require further study.

Animals↗
PubMed1979

Long-term electrode implantation for recording cochlear electrical activity in guinea pigs.

Comparative measurements of the cochlear electrical activity over prolonged periods require long-term implantation of electrodes. During this time, changes in the electrode recording ability and/or impairment of the sound-conducting system, could erroneously be attributed to the experiment. To avoid this risk, an easy and reliable technique is described. The procedure uses the Fallopian canal as a route by which to approach the cochlear potentials' generators, while leaving the middle ear untouched.

Action Potentials↗
PubMed1978

Cerebral tissue response to electrode implantation.

Tissue response to platinum electrodes was assessed after an eight-day implantation period. The regions of study included the cortical areas at the opercular gyri and at the sulcus parieto-occipitalis externus, as well as the sub-cortical white matter in these cases. Perivascular and intraparenchymal hemorrhagic lesions as well as edematous changes characterized both by extensive intra and extracellular swelling were noted. Numerous phagocytic elements and degenerative strucutres were present at the electrode/parenchymal interface. Tissue alterations were asymmetrical as observed both around and at the tip of the implanted electrode. The parenchymal alterations extended from 0.2mm to 3.5mm distance from the electrode path/parenchymal interface. Greater tissue involvement was found in the subcortical white matter as compared to the adjacent cortical gray matter.

Animals↗
PubMed1977

Fabrication of pH-sensitive implantable electrode by thick film hybrid technology.

We report preliminary results of our experiments directed at fabricating pH-sensitive electrodes suitable for in vivo use by means of thick film screening techniques. Our results show that glass membranes of suitable thickness and possessing nearly theoretical sensitivity to pH can be fabricated by this process. A hybrid electrode structure permits the incorporation of a source follower FET amplifier directly adjacent to the pH membrane, significantly reducing response time and noise pick-up. Extension of the basic electrode structure to accommodate membranes sensitive to other ions is discussed.

Biomedical Engineering↗
PubMed1977

[The management of urinary and fecal incontinence due to a neurinoma of the cauda equina with an electrode implanted in the pelvic muscles (Caldwell) (author's transl)].

A woman, aged 49, had a complete sensory and motor deficit of the S2-5 segments with urinary and fecal incontinence due to a neurinoma of the cauda. A Caldwell electrode was implanted surgically into the muscles of the pelvic floor in April 1974. The patient was observed for 2 years thereafter and had an excellent result. The medical and technical problems of treating urinary and fecal incontinence due to a lower motor neuron lesion of S2-5 can be handled satisfactorily with an implanted electrode.

Cauda Equina↗
PubMed1979

[Transvenous electrode implantation into the left heart auricle via vena saphena magna].

A new simple variant of the transvernous implantation of atrial electrodes for the pacemaker therapy is reported. It consist in the fact that via the V. saphena magna under fluorography a hook electrode is shifted into the right auricular appendix by means of a slightly bent conducting wire and is anchored by leading out the hooks.

Cardiac Pacing, Artificial↗
PubMed1975

[A modified method for the determination of locations of chronically implanted electrodes in rabbit brains (author's transl)].

A fast and simple method is described for the localisation of tips of chronically implanted electrodes in the brain of rabbits which may be obtained--under standard conditions--by an intra-aortal injection of a 2% potassium-hexacyanoferrate-III solution. This method also facilitates histological preparations with a thickness of 5 mu only and thus permits a thorough morpho-pathological examination not only in the area of the electrode tips but in adjacent zones as well. The use of a buffered formalin solution also permits certain histochemical examinations to be made, for instance the determination of nucleic acids.

Animals↗
PubMed1976

[A time-saving method for histo-enzymatic studies of brain tissues of animals with chronically implanted electrodes by means of a hard-section microtome (author's transl)].

A time-saving method is described for the localisation of chronically implanted electrodes in the brain of test animals by means of a "Kryostat" hard section microtome which allows both histo-topographic and histo-enzymatic investigations. This is made possible by the incorporation of a three-dimensional microtome holder.

Animals↗
PubMed1975

Histochemistry of trauma after electrode implantation and stimulation in the hippocampus.

Electrodes were implanted into the rat hippocampus in both hemispheres for increasing periods of up to 60 days, and the effects of trauma and electrical stimulation of enzymes controlling cell metabolism in the region of implantation were examined and assessed in relation to studies on humans. In the unstimulated hippocampus as a control, enzyme changes were mainly confined to a narrow area of tissue damage surrounding the electrode. The enzyme changes in response to trauma varied widely; some enzymes controlling tissue respiration showed early and rapid changes, increasing in hyperactive, swollen glial cells and vascular endothelium and decreasing in nerve cells and neuropile. Acid phosphatase activity also increased rapidly in glial cells; other phosphate-releasing enzymes increased more gradually with time. A turning point in these chages was apparent between 25 and 40 days, followed by a reversion to more normal levels at 60 days. Electrical stimulation of the hippocampus in the contralateral hemisphere produced no detectable enzyme changes from those of the unstimulated hippocampus.

Acetylcholinesterase↗
PubMed1978

Study of the motility of the avian oviduct with chronically implanted electrodes.

Electrical activity was recorded in conscious hens from chronically implanted electrodes in the smooth muscle layers of the oviduct. Transport of the egg through the magnum resulted from an inhibition of the electrical activity in the oviduct cranial to the egg and an increased spiking activity caudally. During an ovulatory cycle the progression of the egg was related to four different patterns of the uterine motility: within a sequence, the ovulatory cycles varied according to the duration of Phases 3 and 4.

Action Potentials↗