Urodynamics is an emerging, multifaceted discipline that studies the function of the urinary tract in transporting, storing and discharging urine with the help of fluid dynamics and electrophysiological methods. It was formed in relation to modern electronics and measurement techniques. Urodynamic examination can provide an objective basis for the diagnosis, selection of treatment and evaluation of the efficacy of patients with voiding disorders.
The main urodynamic techniques commonly used include.
① Determination of urinary flow rate ;
(2) Measurement of various pressures;
③Electromyography measurement;
④Dynamic radiological observation, etc.
Urodynamics is divided into two parts: upper and lower urinary tract urodynamics. The former mainly studies the process of urine transport in the renal calyces, renal pelvis and ureter; the latter mainly studies the process of urine storage and discharge in the bladder and urethra. The current examination technique used for the study of lower urinary tract urodynamics is more mature and has become one of the routine examination techniques in urology.
The examination helps people to have a clearer understanding of the mechanism of lower urinary tract dysfunction, and the objective examination results also facilitate doctors to choose more effective treatment methods, which are mainly used in the following areas.
1, female urodynamic examination: used to confirm the diagnosis of female urinary incontinence and clarify the cause.
2, male urodynamic examination: to understand the functional state of the forced urinary muscle and obstruction in patients with prostate hyperplasia, prostate cancer, urethral stricture and other diseases.
3, urodynamic examination in the elderly: mainly used to check the spontaneous instability of the forced urinary muscle and degenerative changes in the function of the forced urinary muscle, common diseases are unstable bladder.
4.Diagnosis and classification of neurogenic vesicourethral dysfunction.
5.Urodynamic examination for children: to clarify whether spina bifida, urethral valve, anorectal anomaly, enuresis and other diseases are combined with abnormalities of vesicourethral function.
Introduced the German urodynamic examination instrument, and currently carries out the following items.
1.Urinary flow rate determination.
Measurement of the volume of urine discharged from the external urethral opening per unit of time is called urine flow rate measurement. This test can reflect the general level of urine storage and excretion function of the lower urinary tract, and is the basic item of urodynamic examination of the lower urinary tract. It is often used as a screening test for urinary disorders and can also provide an objective indicator for evaluating the effectiveness of treatment. The urine flow rate curve is a curve that reflects the instantaneous change in urine flow rate as traced by the uroflowmeter during urine flow rate measurement. The shape of the normal urine flow rate curve is mostly related to age and urine volume, while the abnormal curve is often related to the nature of the disease and can be used for diagnostic reference.
2, bladder pressure volume measurement.
This test mainly reflects the function of the bladder by measuring the relationship between pressure and volume in the bladder. It can trace the process of bladder filling (urinary storage function) and contraction (urinary output function) into a bladder pressure-volume curve (CMG). From the curve, it is possible to understand: bladder volume and compliance; bladder stability; sensory and motor innervation of the bladder. This test is mainly used for the diagnosis and classification of patients with neurogenic bladder. Modern bladder pressure volumetry uses various pressure transducers and recorders, which allow continuous automatic tracing of the corresponding curve and improve the accuracy of the examination. Currently, the tendency is to show the value of this test mainly during the filling phase and to call this test filling bladder pressure volumetry.
3. Measurement of pressure/urinary flow rate during urination.
This is a basic combined technique of lower urinary tract urodynamic examination, which can make accurate judgments of the contractility of the detrusor muscle and lower urinary tract obstruction, thus compensating for the deficiencies of the two aforementioned tests when used alone. This test requires simultaneous measurement of intravesical pressure, intra-abdominal pressure (i.e., rectal pressure), forceps contraction pressure (intravesical pressure minus intra-abdominal pressure) and urinary flow rate during urination. The test involves the insertion of manometry catheters into the bladder (via urethral or suprapubic puncture) and rectum, which are connected to their respective pressure transducers. When the subject urinates for urine flow rate measurement, the recorder can trace four corresponding curves simultaneously.
The pressure curve of the detrusor muscle is plotted by the electronic circuitry in the instrument. From the four curves recorded, it is possible not only to understand the parameters of maximum voiding pressure at the time of bladder neck opening, systolic pressure and urinary flow rate at the time of maximum urinary flow rate, but also to diagnose certain diseases (such as dysfunction of the sphincter of the forceps) by the temporal relationship between pressure and urinary flow curve.
Each of these tests focuses on a particular aspect of lower urinary tract function, so they should be used selectively in combination with the patient’s specific situation in order to obtain a complete understanding of lower urinary tract function. At present, the more advanced urodynamic testing instruments are often combined, and in addition to the above-mentioned tests, several or all of them can be selected for simultaneous combined testing according to needs. The examination data are recorded on recording paper, television video and cinematography for subsequent retrieval. Some of the newly introduced examination instruments also have computer devices that can analyze and process certain curves and images, making the examination results more accurate.