Gerald W. Timm

Treatment of urinary incontinence by implantable prosthetic sphincter

Abstract A completely implantable prosthetic urethral sphincter was implanted in five patients with urinary incontinence. The preliminary results indicate that this prosthesis successfully restored continence to all five patients. These patients included a forty five-year-old woman who had persistent stress incontinence in spite of standard operative procedures, a thirty-six-year-old woman with neurologic bladder secondary to meningomyelocele, a thirteen-year-old girl with traumatic seventh-vertebra paraplegia and neurologic bladder, an eighteen-year-old man whose neurologic defect from myelomeningocele caused total urinary incontinence, and a twenty-four-year-old woman with cauda equina injury resulting in neurologic bladder dysfunction.

Pudendal sexual reflexes: Electrophysiologic investigations

Abstract Electrophysiologic testing of neural pathways involved in sexual function have not previously been performed. This study is a description of the normal transit time and electrophysiology of impulses in the pudendal reflex pathways concerned with ejaculation.

Neurology of Micturition

The understanding, diagnosis and management of neurologic dysfunction of the bladder have undergone considerable changes during the last 2 decades. These changes were the result of animal experimentation into physiology and pharmacology and the accelerated use of biomedical engineering technology. The implementation of these advances will require physician re-education in the neurology of micturition.

Cystometry V. Bladder sensation

Bladder sensation is an important variable in cystometry. Sensory complaints are a valuable portion of the history which may be further defined and documented by the cystometric examination.

A Decade of Experience with Electronic Simulation of the Micturition Reflex

Neurologic dysfunction of the urinary bladder is a frequent and morbid sequel to many diseases of the nervous system including spinal injury. Ten years of research into electronic techniques to return urinary bladder function to the control of the patient have resulted in a multicomponent system which is effective in the laboratory. However, clinical applications of this technique have been frustrated by unknowns regarding smooth muscle function in neurologic disease. We anticipate that a review of our efforts in this field will stimulate other investigators to delineate these unknowns and accelerate the employment of prosthetic devices to aid bladder evacuation.

Detrusor and urethral electromyelography.

AbstractAn electrophysiological method has been developed to test the structural integrity and function of the reflex arcs concerned with micturition. The technique has been used to delineate neuropathic involvement of the lower urinary tract.

Cystometry I. Introduction

Abstract Cystometry, a clinical test for assessment of detrusor function, may be used as a supplement to history and physical examination in patients with neurologic dysfunction of the urinary bladder. The test is based on the implicit assumption that the detrusor reflex response is a necessary prerequisite to efficient voiding. Since some patients may void by straining, cystometry should be supplemented by urodynamic and neurologic procedures for evaluation of micturition.

An implantable mechanical urinary sphincter: a new nonhydraulic design concept

OBJECTIVES We present data concerning an artificial implantable mechanical urinary sphincter that was designed to eliminate the inherent problems of the current hydraulic artificial urinary sphincter (American Medical System [AMS] 800). Our goal was to design a sphincter that creates urethral compression similar to the AMS 800 but creates the force without the use of fluid, thereby eliminating as much as 50% of the reoperations seen with the AMS 800, which occur because of fluid-related malfunctions. METHODS An implantable artificial mechanical sphincter consisting of a compressive coil encompassed in a polytetrafluoroethylene sheath was devised and tested in 6 live mongrel dogs to establish compressive force versus bladder pressure data, so as to provide data to create a mechanical sphincter for use in humans. RESULTS A direct relationship between bladder leakage pressure and cable tension force was demonstrated in all 6 experimental animals, thereby creating a mathematical equation that can be used by mechanical engineers to design a mechanical sphincter for use in humans. CONCLUSIONS This study demonstrated that a mechanical urinary sphincter can be created that will provide continence and eliminate the problems associated with the hydraulic aspect of the AMS 800. In doing so, nearly 50% of the reoperations seen with the current AMS 800 can be eliminated, thereby improving the quality of life of patients for whom an artificial urinary sphincter is indicated.

Feasibility of Using a Computer Modeling Approach to Study SUI Induced by Landing a Jump

Stress urinary incontinence (SUI) occurs due to anatomic and/or neurologic factors involving connective tissues, muscles and nerves. Although SUI is more common in post-menopausal and multiparous women, studies have also shown a high prevalence of SUI in young, physically fit female athletes. With a goal toward dynamic subject-specific mechanical characterization of the interaction between anatomical structures during physical activities that elicit SUI in females during physical or daily activities, a computer aided design (CAD)-based computer model of the female pelvis has been developed to test the feasibility of the computer modeling approach in understanding the measurable differences between stress-continent and stress-incontinent women. In the present study, a fluid–structure interaction analysis was conducted by using the finite element (FE) analysis technique based on the CAD-based computer model of the female pelvis to investigate the urine leakage in females during jumping. To the best of our knowledge, this is the first application of a fluid–structure interaction FE analysis approach in understanding the mechanisms of SUI in females. Through a series of computer simulations, the effects of varying impact forces determined by jumping height and bladder volume were investigated. The dynamic computer simulation results revealed that jumping heights have a significant influence on the volume of urine leakage caused by the landing impact of jumping. Bladder volume did not have a significant influence on leakage when the jumping heights were smaller than 1 ft, which indicates that normal walking (corresponds to a jumping height smaller than 0.1 ft) is not the primary cause of urine leakage for healthy females. The computer simulation results also showed that the deformation difference between the anterior and posterior portion of the female pelvis causes opening of the urethra and resultant urine leakage. The present study demonstrates the feasibility of using a computer modeling approach to study female SUI during physical and daily activities.

Bladder Volume Sensing by Resistance Measurement

The resistance of the urinary bladder, as measured between two electrodes attached to the external bladder wall at frequencies above 100 kHz, is proportional to the bladder volume for properly placed electrodes. The feasibility of using an oscillator, the frequency of which is controlled by the bladder interelectrode resistance, to provide an electrical signal proportional to bladder volume for use in connection with an electronic bladder stimulator is presented. The implications of this result are discussed.