Biomedical subjects

J S Walter

Publications and source records attributed to J S Walter.

41 records · Page 3Linked to original sources

PubMed1989

Sacral epidural electrodes for voiding in the chronic spinal dog.

Recent reports have shown that electrical stimulation of the bladder wall or sacral nerves is effective for bladder management in the spinal cord injured (SCI) patient. However, less invasive methods are needed for electrode implantation. A modified percutaneous procedure for implanting needle electrodes in the sacral canal was evaluated. Stimulation with these electrodes were effective for inducing voiding with little residual volume after the recovery of bladder reflexes, 3 weeks after experimental spinal cord injury in the dog. An optimum electrode arrangement involved a single midline monopolar electrode located between sacral foramina L7 and S1. However, at low stimulating current, lateral electrodes adjacent to sacral nerves were more effective than midline electrodes for inducing voiding. Stimulation parameters that were effective for daily voiding were 10 pps, 1.5-5 mA, 0.3 ms pulse duration, and 2- to 3-second stimulation periods.

Animals↗

PubMed1988

Idiopathic anejaculation treated by vibratory stimulation.

Idiopathic anejaculation is a rare cause of infertility usually treated by psychotherapy. However, electrovibration may be a simple, noninvasive adjunct to the treatment of this disorder. In our two cases, we obtained ejaculate adequate for insemination in one patient and noted some gain in orgasmic sensation in the other. The success in these two infertile patients who had already undergone lengthy psychotherapy is promising. Nevertheless, psychotherapy will continue to be the standard of therapy until we have more experience with penile electrovibration.

Adult↗

PubMedDate not supplied

Comparison of electrical transients and corrosion responses of pulsed MP35N and 316LVM electrodes.

Functional neuromuscular stimulation (FNS) is often limited by electrode malfunctions such as corrosion and breakage, particularly for intramuscular and epimysial type electrodes. As a result, the electrochemical charge injection characteristics and corrosion responses of single strand 316LVM stainless steel and MP35N nickel-cobalt alloy electrodes were evaluated in vitro. For charge balance, capacitor coupled monophasic protocols with varying charge injections were employed. Electrodes were evaluated with either positive-first or negative-first pulses, 60 Hz, 100 microsec pulse duration, and stimulation periods from 100 to 240 hours. Charge injection densities ranged from 20 to 80 microC/cm2. For both anodic-first and cathodic-first pulsing, the potential transients for the MP35N electrodes were more extreme than for the 316LVM electrodes over the test period, and increased corrosion was apparent on the MP35N electrodes from both optical and scanning electron microscopy. Therefore, 316LVM, but not MP35N, may be suitable for FNS applications with charge injection densities less than 40 microC/cm2.

Alloys↗

PubMedDate not supplied

Behavioral therapy for urinary incontinence.

Urinary incontinence is a serious and costly problem that affects many patients, especially the elderly. Because this population is growing, many methods of treatment for urinary incontinence have been developed. However, even though the behavioral techniques have been available for years, only recently has the use of formal behavioral methods become more popular as a less invasive alternative for the treatment of incontinence. These methods have proven effective in several series. This article reviews the treatment of types of urinary incontinence with behavioral therapeutic techniques.

Behavior Therapy↗

PubMedDate not supplied

Feasibility of implant driven micturition in paraplegic dogs.

OBJECTIVE: This study evaluates the feasibility of using existing technology for implant driven micturition in paralyzed dogs (part I) and also examines a less invasive technique for implant driven micturition (part II). STUDY DESIGN: Part I. Sacral nerve root dimensions and bladder and urethral pressure responses to intradural and extradural sacral nerve root stimulation were measured to determine the optimal location and size for sacral nerve root electrodes. Part II. Sacral nerve roots were stimulated via wire electrodes introduced into the S2 foramina. ANIMALS OR SAMPLE POPULATION: Ten dogs (five dogs in part I and five dogs in part II). METHODS: Part I. Microtip pressure transducers were used to monitor bladder and urethral pressure responses to sacral nerve root stimulation with tripolar hook electrodes. After euthanasia, sacral nerve root, and spinal canal dimensions were measured. Part II. Bipolar electrical stimulation of the sacral nerve roots was performed by introducing wire electrodes into the S2 foramina. Bladder and urethral pressures were recorded as in part I. RESULTS: Part I. Stimulation of SI produced an increase in urethral, but not bladder, pressure. Stimulation of S2 or S3 produced increases in bladder pressure and decreases in urethral pressure. Intradural and extradural nerve roots were not significantly different with respect to nerve dimensions or effects on nerve stimulation. Part II. High bladder pressures were achieved, but effective voiding could not be produced, primarily because of urethral resistance. CONCLUSIONS: Part I. Extradural implantation was determined to be the most appropriate site based on ease of dissection, nerve root dimensions, and decreased risk of iatrogenic trauma. Enough space is available to implant two to four tripolar spiral nerve cuffs. Part II. Transforaminal sacral nerve root stimulation did not effectively empty the bladder. CLINICAL RELEVANCE: Clinical trials in paraplegic dogs are necessary to evaluate the number of sacral nerve cuff electrodes necessary to produce effective bladder emptying.

Animals↗