Arthur M. Sterling

Role of inner urethral softness in urinary continence.

Given adequate external squeeze upon suitable urethral geometry, continence depends on the mechanical properties of the outflow tract wall. Evidence indicates that these mechanical properties include an ability to deform and behave in a fluid-like manner.

The Physical Basis of Obstructive Uropathy

A majority of urologists probably would not agree on a precise definition of obstruction, although most would agree that a reduction in urinary flow rate and an elevation of detrusor pressure are early signs. Beyond these relatively clear indications, however, the concepts of obstruction get a bit fuzzy. Is obstruction always associated with a constriction of the urethra? Does a constriction of the urethra necessarily imply obstruction? What are the actual physical mechanisms associated with lower urinary tract obstruction? Is an understanding of the physical basis of obstruction really that important?

The Physical Basis of Some Urodynamic Measurements

This report concerns certain principles of physics that are relevant to the clinical practice of Urology as well as the research urodynamicist. Supplemental material is available in previous publications for the physiologist, cardiovascular, dynamicist, anesthesiologist and the like. The material is fairly recent only in its application to the lower urinary tract. Pressure-volume relationships were applied to be cardiovascular system more than 20 years age. Indeed, for those interested in urodynamic methods, there is a vast fund of useful pertinent information in the literature on vascular dynamics. The problems of steady and unsteady flow in flexible structures are common to both specialties. It would be unfortunate if urodynamicists were required to learn of the phenomena and their implications by the drudgery of repeated measurements rather than taking guidance from previous work. This report is intended to serve as an introduction to the approach and, hopefully, will stimulate those who are interested in urodynamic methods to seek out this information and to interpret their measurements in the light of fundamental physical phenomena that have been described and analyzed.

The Standardization of Terminology of Lower Urinary Tract Function

The terminology of lower urinary tract function will be standardized by the ICS. This report contains the recommendations dealing with urinary incontinence, procedures related to the evaluation of urine storage (cystometry, urethral closure pressure profile) and units of measurement.

Analysis of drop intervals in jets modelling obstruction of the urinary tract.

The external human urine stream breaks into drops, the sequence and properties of which contain information about the condition of the urinary outlet tract. These are studied wih an optical instrument, the Urinary Drop Spectrometer. One particular analysis, the distribution of time intervals between the drops, is made with data taken with a simplified brass model of the adult male urethra. A quantitative measure of the sensitivity of this analysis to the size and location of annular obstructions is presented. Similarities to results for several common types of obstruction in humans are exhibited and discussed.

Evaluation of inner urethral softness Part II. Clinical study using new grooved probe device

This study, in incontinent women, evaluates the effectiveness of a new device to measure properties of urethral softness. The device is a straight sound with a longitudinal groove cut along its surface. It is inserted through the urethra and into the bladder. A soft, deformable urethra is expected to fill itself into the groove and prevent the loss of urine from the bladder along the groove to the outside. Using this instrument it is learned that (1) postmenopausal women are less able to seal the urethra than younger ones; (2) as the urethra is stretched it is less able to form a seal; and (3) the anterior urethra is the weakest link in sustaining continence when tested by methods used in this program.

The Urinary Drop Spectrometer in Diagnosis

The urologist has long sought a simple diagnostic means of evaluating benign prostatic hypertrophy (BPH). It is not enough to say that the prostate is large, and it may not be enough to say that the flow rate is low. Some enlarged prostates have little clinical effect, whereas others may produce serious obstruction and yet seem almost normal to palpation. Flow rate may be low for a variety of reasons3 other than prostatic obstruction. The problem faced by clinicians is to find a simple and safe way to diagnose prostatic obstruction, preferably before infection or damage to the upper urinary system occurs. The urinary drop spectrometer (UDS) may provide one such way.10,11,13

Measuring softness of inner female urethra. Part I. Simple new device.

A new device is described to measure clinically the softness of the female urethra. It is a rod-shaped urethral sound with a longitudinal groove along its surface. The sound is constructed in sizes 12 to 24 French. Each has one groove which is 2 mm wide and either 2, 2.5, or 3 mm deep. The groove is 11 cm long. When inserted into the filled female bladder per urethram, the groove will span the urethra from the bladder to the outside. If the urethral inner lining is soft and deformable, it will fill itself into the groove and prevent leakage of urine from the bladder along the groove to the outside. If the urethra is relatively rigid, urine will leak from the bladder. This instrument permits testing of women to determine urethral properties in preventing leakage when studied with a range of probe sizes.

Future Prospects for Urodynamic Study in Clinical Evaluation of Benign Prostatic Hypertrophy

It is estimated that one-third of all men older than 60 have enlarged prostates, yet only 25% of them complain of voiding dysfunction.7 Many of these men also have no gross symptoms of obstructed flow. These observations are in accord with the findings of Yalla et al.,12 who discovered that men with moderate or even severe enlargement of the prostate can be without symptoms of obstruction. When tested by urodynamic methods, obstruction was found to be either mild or altogether absent. On the other hand, Platenkamp9 observed that totally asymptomatic men can have occult obstruction that may not be evident unless sensitive testing techniques are used. Using the urinary drop spectrometer (UDS), 461 apparently normal men in the armed services (age 19–55 years) were surveyed at random. They produced a total of 4109 voidings. Of the 461, Platenkamp found 29 who had UDS patterns that were compatible with obstruction. The age groupings of the men in the study and of those with abnormal UDS patterns are shown in Table 1.