Urodynamic examination is the application of the basic principles and methods of fluid mechanics and electrophysiology to detect the urine flow rate, pressure and bioelectrical activity in each part of the urinary tract based on the anatomical characteristics of each part of the urinary tract, so as to understand the function and mechanism of urinary tract drainage. Based on the changes in the urinary function of each part, we diagnose dysfunctional diseases of each part and their nature, as well as their pathophysiological changes, and provide reference for treatment. It can help in the diagnosis of dysfunctional diseases of urination, and it can provide objective materials for treatment and treatment effect, and it is the most common examination method for the diagnosis and treatment of functional diseases of the lower urinary tract in clinical practice. The scope of application of the test is to diagnose and provide treatment plans for lesions of the entire urinary tract from the renal pelvis, ureter, bladder, urethra to the urethral orifice, especially for any lesions related to urine flow, muscle contraction and urine retention sites. For idiopathic hydronephrosis, dynamic obstruction of ureteral dilatation, ureteral stenosis, ureteral dysfunction, giant ureter, and other lesions, urodynamic examination of the upper urinary tract is indicated. Bladder and urethral lesions (voiding disorders) are most suitable for urodynamic examination, such as urinary urgency, urinary frequency, difficulty in urination, thin urinary line, urinary ejection, painful urination, residual urine in the bladder, prostatic hyperplasia, female urethral syndrome, urinary incontinence, enuresis, dribbling, intermittent urination, invisible spina bifida, lumbar-thoracic spine trauma or fracture, paraplegia, disc herniation and any cause of abnormal urination. Urodynamic examination precautions Pure urine flow rate determination: You should drink more water before the examination and feel anxious to urinate before the examination, because to do a good urine flow rate, 200-400ml of urine is needed to be accurate. During the examination, urination should be done as usual, without straining or holding your breath, and all the urine should be drained in the manometric urinal at once. Urodynamics complete examination: it is best to empty the bowels before the examination, and during the examination, you should cooperate with the medical staff, not be nervous, and follow all the doctor’s orders. Only by cooperating with the doctor’s work can we obtain the best results of the examination.