Electrical stimulation of pelvic floor muscles for female stress urinary incontinence

  Electrical stimulation is the stimulation of the pelvic tissues and organs or the nerve fibers innervating them with electrical currents of specific parameters to modify the functional state of the bladder/urethra by direct action on the effectors or by influencing the activity of the nerve pathways in order to improve the urinary storage or voiding function. Electrical stimulation was first proposed by Caldwell in 1958, and its clinical application began in the mid-1970s. Nowadays, electrical stimulation has become one of the treatment methods for lower urinary tract dysfunctional diseases and has become an increasingly important treatment method for some voiding dysfunctional diseases.  The specific method: electrodes are inserted vaginally or anally to stimulate the pelvic floor muscle groups with intermittent electrical currents, mostly in the form of rods for vaginal stimulation in married women, and in the form of dumbbells for anal stimulation in men. The electrical stimulation parameters used for electrical stimulation vary from one report to another. The electrical parameters generally used are: 4-10mA, wave width l-5ms, frequency 20-50Hz (low frequency of 20Hz is mostly used). Treatment is given twice daily for 8-12 weeks.  This method is mainly used to treat stress incontinence, urge incontinence and mixed incontinence.  Stress incontinence is associated with a decreased ability to close the urethral sphincter and a delayed pelvic floor muscle reflex. Inadequate pelvic floor and periurethral muscle and tissue support, and muscle fatigue under stressful conditions are associated. Electrical stimulation activates the pelvic floor muscles both directly and through neural reflexes, reestablishing their neuromuscular excitability and increasing their contractility; it also increases the number of fatigue-resistant muscle fibers and enhances their activity in the transverse pelvic floor muscles after receiving longer-term electrical stimulation. Urodynamic examinations showed an increase in urethral closure pressure after treatment, with particularly marked changes in maximum urethral closure pressure. The use of high-frequency current (30-35 Hz) in such patients is effective.  Mechanism of action on urge incontinence: There are two neural reflex pathways between the normal human pelvic floor muscle and the bladder, namely the pubic nerve, sacral medulla and pelvic nerve (parasympathetic) and the pubic nerve, thoracic medulla and infra-abdominal nerve (sympathetic). When the pelvic floor muscle is stimulated, local muscles and nerves are stimulated and conductive nerve impulses are generated, which inhibit the contraction of the detrusor muscle by exciting the sympathetic pathway and inhibiting the parasympathetic pathway. The use of low-frequency current (below 10 HZ) is effective in such patients.  There are many reports on the efficacy of pelvic floor muscle electrical stimulation, but the results vary widely, with an effective rate ranging from 7% to 91%, but most authors consider the effect to be more satisfactory, with significant improvements in both subjective indicators (including voiding status, number of 24-hour incontinence, incontinence volume, etc.) and objective indicators (including leakage point pressure, voiding volume, residual urine volume, bladder and segmental urethral pressure, maximum urethral pressure, etc.). The main side effects were: possible vaginal irritation and infection due to repeated manipulation in a few patients.