Urinary incontinence can be divided into urge incontinence, stress incontinence (urethral hypermobility) and/or intrinsic sphincter deficiency, mixed incontinence and overflow incontinence.
Intrinsic sphincter deficiency (ISD) is also called Type III stress incontinence, low pressure urethra and drainpipe urethra. The risk factors for this are advanced age, radiation and prior incontinence surgery. The clinical features are severe incontinence often with minimal changes in position. The exam may reveal minimal bladder neck descent; the Q-tip angle will be less than 30°; there is poor urethral coaptation on endoscopy; and there is an open bladder neck on fluoroscopy. The mean urethral closure pressure is less than 20 cm of water and the leak point pressure is less than 60 cm of water
Low urethral pressures are associated with lower surgical success rates. Periurethral bulking injections are recommended as first line treatment for women with intrinsic sphincter deficiency without hypermobility.
Genuine stress incontinence can be diagnosed with 97% confirmation by urodynamic studies in patients whose predominant complaint is stress incontinence, who have a positive cough stress test, whose post-void residual is less than 50 cc and who have a functional bladder capacity of at least 400 cc based on 24 hour frequency/volume chart. With pelvic floor exercises (Kegel exercises), most studies show the majority of patients improve (50 to 75%) but few (10 to 15%) are completely dry. Pelvic floor exercises are strongly recommended for women with stress urinary incontinence.
Pelvic organ support devices such as tampons and Hodge pessaries reduce exercise incontinence. Diaphragms reduce stress urinary incontinence but data are not available to recommend or discourage the use of pessaries for the treatment of urinary incontinence in women.
Pelvic floor electrical stimulation which produces a contraction of the levator ani, external urethral and anal sphincters, accompanied by reflex inhibition of the detrusor has shown benefit for stress urinary incontinence compared to placebo (48% versus 13% objective cure).
Estrogen therapy shows modest effects with rare cures and may work by inducing alpha-receptors in the urethra. It is recommended as adjunctive therapy.
The AUA female stress urinary incontinence clinical guidelines panel concluded that for genuine stress incontinence after 48 months retropubic suspensions and slings appear to be more efficacious than transvaginal suspensions, and more efficacious than anterior repairs. The literature suggests higher complication rates when synthetic materials are used for slings.
For detrusor instability, pelvic floor electrical stimulation showed a 49% objective cure rate in a multi-center study. Anticholinergic drugs are the first line pharmacologic therapy for patients with detrusor instability including the medications oxybutynin and tolterodine.
Mixed incontinence frequently requires a combination of treatments applicable to genuine stress incontinence and to genuine stress incontinence.
Genuine stress incontinence which is the involuntary loss of urine which occurs when the intravesical pressure exceeds the maximal urethral pressure in the absence of a detrusor contraction, can be treated by medical (behavioral/biofeedback/pelvic floor re-education) therapy if the fascial attachments are intact. If the fascial attachments have broken, then surgical therapy is required. At the time of surgical intervention, the fascial breaks must be repaired. Thus successful surgery requires that the structures involved in urethral and bladder neck support be examined carefully and any tears and breaks be approximated appropriately. These structures include the endopelvic fascia, the tendinous arch, and the pelvic diaphragm. The perineal membrane and the perineal body provide additional support.
If surgery is required, the endopelvic fascia must be examined and repaired. The first layer of the pelvic floor is the endopelvic fascia, which connects the upper vagina, cervix, and uterus to the pelvic sidewalls. This fascia consists of pubourethral ligaments, the urethropelvic ligaments and the uterosacral ligaments which are level with the cervix and uterus. The vertical orientation of these ligaments creates a suspension system, which holds the cervix and upper vagina over the levator plate. If the endopelvic fascia has suffered tears, these must be repaired at the time of incontinence surgery.
The tendinous arch or the arcus tendinous fasciae is a fibrous band of fascia that is attached ventrally to the pubic bone and dorsally to the ischial spine. It provides a lateral attachment for the pelvic floor muscles and ligaments. If the arcus tendons has torn away from its attachment to the obturator internus muscle at the white line, this must be reattached (paravaginal repair) to ensure a complete repair of the defects contributing to the urinary incontinence.
The pelvic diaphragm is composed of two muscles, the levator ani muscle and the coccygeal muscle. The perineal membrane or the urogenital diaphragm is a fibrous layer spanning the anterior triangle of the pelvic outlet. The perineal body composed of the bulbospongiosus, the ischial cavernosus and superficial transverse perinei fuse dorsally to form the perineal body. Some fibers of the external anal sphincter are also attached to the perineal body. This muscular structure gives stability to the pelvic organs. It does not appear to significantly influence the continence mechanism.
The tissue that supports the urethra forms a sling under the upper and middle portions of the urethra. This sling is a segment of the anterior vaginal wall that is attached to the muscles of the pelvic floor (levator ani muscles principally) and the tendinous arch. The levator ani muscles not only help support the visceral structures at rest by maintaining a constant tone but also act as a backup to the endopelvic fascia and serve as the principal support during suddenly increased intra-abdominal pressure. The connection of the urethral to the tendinous arch assists levator support and limits the downward descent of the vesical neck when the levator muscles are relaxed or overcome. Because support of the bladder neck and proximal urethra comes from both muscles and ligaments, proper intrapelvic support requires active muscular contraction during stress along with the firm strength of the ligaments and vaginal wall. Any pelvic floor denervation, therefore, may contribute to stress urinary incontinence.
The objective of surgery is restore urinary continence without creating outlet obstruction. When urinary incontinence is mostly related to a defect in bladder neck and urethral support, a bladder neck suspension is indicated. When incontinence is caused by severe loss of bladder neck and urethral support associated with opening of the bladder during stress, a sling procedure is probably the best choice.
Using physiotherapy is appropriate in all cases because it can help restore continence by reinforcing the pelvic floor muscles or the striated urethral sphincter. Using either pelvic floor exercises and/or electro-stimulation can sometimes eliminate the need for surgery. Biofeedback enhances learning and focuses attention on agonistic (levator ani) and antagonistic (rectus abdominus) muscles. Through the use of multi-channel biofeedback, therapy concentrates on inhibiting antagonistic activity while attempting to enhance agonistic activity. If patients have lost the reflex contraction of the levator ani during a sudden increase in abdominal pressure, rehabilitation techniques can help them relearn this reflex.
The Burch procedure is considered by many to be the gold standard for surgical treatment of genuine stress incontinence. The Burch procedure requires the elevation of the anterior wall of the vagina to the level of the origin of the paravaginal fascia by suspension from Cooper's ligaments (iliopectineal ligaments). A properly performed Burch procedure has a 93% five-year cure rate. Again if a paravaginal defect exists, this must also be repaired at the time of the retropubic suspension. In addition, all pelvic floor defects should be repaired at the same surgery.