Stress urinary incontinence (SUI) refers to the involuntary leakage of urine from the external urethra when abdominal pressure increases, such as sneezing, coughing or exercise. The prevalence of female urinary incontinence is currently close to 50% according to global statistics, and severe urinary incontinence is about 7%, of which about half is SUI, and the prevalence of SUI in Chinese adult women is 18.9%. This non-fatal disease is a more common problem in middle-aged and older women, causing emotional anxiety, embarrassment and frustration, and has been compared to a “social cancer” due to urine loss, body odor, limiting social activities, as well as physical activity and physical labor, and poses a serious impact on women’s quality of life and health status. This article reviews the current status of the treatment of this disease in Jane as follows.
1. Factors associated with the development of SUI and pathophysiological mechanisms
1.1 Factors associated with the onset of SUI.
(1) Age: The prevalence of female urinary incontinence gradually increases with age, with a high incidence at 45-55 years of age. The correlation between age and urinary incontinence may be related to pelvic floor laxity, estrogen reduction and degenerative changes in the urethral sphincter with age.
(2) childbirth: the number of births is positively correlated with the occurrence of urinary incontinence; women whose first birth is between 20 and 34 years of age have a higher correlation between the occurrence of urinary incontinence and childbirth than other age groups; those who are too old for childbirth are more likely to have urinary incontinence; women who give birth vaginally are more likely to have urinary incontinence than women who give birth by cesarean section; women who give birth by cesarean section are at greater risk of urinary incontinence than women who have not given birth The risk of incontinence is greater in women who have had a cesarean section than in women who have not had a baby; the use of forceps, suction devices, and contractions to speed up labor also increases the likelihood of incontinence; and the risk of incontinence is greater in mothers with large fetuses.
(3) Obesity: women with abdominal obesity in particular have a significantly higher chance of SUI.
(4) Pelvic organ prolapse: SUI and pelvic organ prolapse are closely related, and both are often present together. In patients with pelvic organ prolapse, thinning and disorganized smooth muscle fibers of pelvic floor support tissue, connective tissue fibrosis and muscle fiber atrophy may be associated with the occurrence of SUI.
(5) Other factors: constipation, alcohol consumption, menopause, respiratory diseases, chronic pelvic pain and other related factors.
1.2 Pathophysiological mechanisms of SUI: There is still no definite conclusion, but the more unified view is that its pathogenesis can be broadly divided into four types.
(1) Bladder neck and proximal urethra subluxation: various causes of pelvic floor muscles and connective tissue degeneration, damage and weakness, resulting in bladder neck and proximal urethra subluxation, urethral relaxation, functional urethra shortening, the increased abdominal pressure is transmitted only to the bladder and less to the urethra, the pressure in the bladder is higher than the pressure in the urethra, urinary incontinence occurs. This is typical of anatomical incontinence.
(2) The closed function of the urethral mucosa is reduced: normal urethral mucosal folds have the role of a sealing pad, which can stop the leakage of urine. Advanced age, urethritis, urethral injury and other reasons lead to mucosal fibrosis, mucosal atrophy and thinning, and decreased elasticity, which can make the closed function of the urethral mucosa diminish or disappear.
(3) Decreased function of the intrinsic urethral sphincter: degeneration and damage to the function of urethral smooth muscle, urethral transverse muscle, and periurethral transverse muscle, resulting in decreased urethral closure pressure.
(4) Dysfunction of the nervous system that governs the structure of the urinary control tissues: the structure and function of the urethra itself, and the nerve dysfunction associated with the supporting tissues around the urethra can lead to urethral closure insufficiency and urinary incontinence.
2.Diagnosis
In addition to general history and gynecological examination, there are special related examinations for the diagnosis of female SUI, including urodynamic examination, pressure test, finger pressure test, urine pad test, urine routine and urine culture examination, swab test and urinary tract imaging, among which the most noteworthy is urodynamic examination. Urodynamic examination is to graphically and numerically represent the symptoms of urinary incontinence and provide a pathophysiological explanation for the patient’s suffering, providing an objective basis for the clinical formulation of the correct treatment plan and assessment of its effectiveness. Without the guidance of urodynamic examination and assessment, the treatment of SUI will be somewhat blind and lack objective basis, and SUI should be diagnosed only after urodynamic examination. For patients with mild or moderate SUI treated non-operatively, urodynamic examination is not necessary, but before invasive surgical treatment, urodynamic examination can help to diagnose SUI staging, select a reasonable surgical procedure and exclude other lower urinary tract symptoms.
3.Treatment
SUI is usually a non-fatal disease, and the main goal of treatment is to improve the patient’s quality of life. Therefore, the efficacy of a treatment for SUI should be judged not only by the degree of relief of incontinence, but also by whether the treatment will bring about other complications that will impair the patient’s quality of life. The efficacy of treatment for urinary incontinence can be summarized by a single indicator that equates to an improvement in quality of life.
3.1 Non-surgical treatment
The International Advisory Committee on Urinary Control (ICI) and the National Institute for Health and Clinical Excellence (NICE) in the UK recommend that non-surgical treatment should be the first choice for patients with urinary incontinence, particularly in patients with mild to moderate SUI. Non-surgical treatment can also be used as an adjunctive treatment before and after surgery. Non-surgical treatment has the advantage of fewer complications and less risk, and is particularly suitable for elderly patients to reduce their incontinence symptoms.
3.1.1 Lifestyle interventions: weight reduction, smoking and alcohol cessation, reduction of caffeinated beverages, avoidance of activities that increase abdominal pressure, and treatment of chronic abdominal pressure-increasing diseases such as respiratory disease and constipation.
3.1.2 Pelvic floor muscle training (PFMT): The preventive and therapeutic effects on SUI in women have been confirmed by numerous meta-analyses and randomized controlled studies. This method is convenient, partially effective, and applicable to all types of SUI. PFMT can only be effective if the pelvic floor muscles are trained to a significant amount, and can be implemented as follows: continuous contraction of the pelvic floor muscles (retraction) for 2-6 seconds, relaxation rest for 2-6 seconds, and so on for 10-15 repetitions. PFMT can be performed using biofeedback methods, which are more effective than PFMT with only verbal instruction from the physician. the literature reports that the short-term efficiency of PFMT can reach 50%-75%, but there are disadvantages of poor compliance and training skills that are not easy to master.
3.1.3 Pelvic floor electrical stimulation therapy: Repeated stimulation of pelvic floor muscles by electric current enhances the contraction force of pelvic floor muscles; feedback inhibits sympathetic reflexes, reduces bladder activity, and improves urinary control. There is a large variation in the literature, and large samples and long-term follow-up randomized controlled studies are needed. Biofeedback and pelvic floor electrical stimulation can be used for patients who cannot actively contract the pelvic floor muscles. It can also be applied in combination with PFMT for better results, and the treatment effect is comparable to PFMT. Some patients may experience adverse effects such as vaginal infection, bleeding, perineal discomfort and skin rash.
3.1.4 Drug therapy: Drug therapy can reduce the number of urinary leakage and improve the quality of life of patients. The main principle of action is to increase urethral closure pressure and improve urethral closure function.
(1) Selective α1 adrenergic receptor agonists: through activating α1 receptors of urethral smooth muscle and somatic motor neurons, it increases urethral resistance, with an efficiency of about 30%. Commonly used drugs are Midodrine hydrochloride and so on. Dosage: 2.5-5mg/dose, 2-3 times daily. Efficacy: Effective for SUI, especially when combined with estrogen or pelvic floor muscle training. Contraindications: urge incontinence, excessive nocturia, hypertension, glaucoma. Side effects: hypertension, palpitations, headache and extremity chills, and in severe cases, stroke.
(2) Promethazine: increases the contractility of urethral smooth muscle by inhibiting the reabsorption of norepinephrine and 5-hydroxytryptamine from adrenergic nerve endings; and can affect the contractile function of urethral transverse muscle from the spinal cord level; inhibits bladder smooth muscle contraction and relieves urge urinary incontinence. Dosage: 50-150 mg/d. Efficacy: Although several open clinical trials have shown that it can relieve symptoms of stress urinary incontinence and increase urethral closure pressure, its efficacy needs to be confirmed by randomized controlled clinical trial studies. Contraindications: Use with caution in patients with heart failure and in the elderly. Side effects: cholinergic receptor blockade symptoms such as dry mouth, blurred vision, constipation, urinary retention and postural hypotension; H1R blockade symptoms such as sedation and coma; cardiac arrhythmias, reduced myocardial contractility; addictive; overdose can be fatal.
(3) β-adrenoceptor antagonists: blocking urethral β receptors; enhancing the effect of norepinephrine on α receptors. Efficacy: open cohort studies have confirmed significant efficacy, but there are no relevant randomized controlled clinical trial studies. Side effects: postural hypotension, cardiac dysregulation.
(4) Estrogen: Promotes proliferation of the urethral mucosa, submucosal vascular plexus, and connective tissue; increases the number and sensitivity of alpha-adrenergic receptors. Maintains active tone of the urethra by acting on estrogen-sensitive receptors in four layers of tissue: epithelium, blood vessels, connective tissue and muscle. Dosage: Administered orally or topically via the vaginal mucosa. Efficacy: Estrogen was once widely used in the treatment of SUI to relieve symptoms of urinary frequency and urgency, but it does not reduce urinary incontinence and has the risk of inducing and aggravating incontinence. Side effects: Increase the risk of endometrial cancer, breast cancer and cardiovascular disease.
3.2 Surgical treatment
Indications for surgical treatment include.
(1) Patients with poor results or non-adherence to non-surgical treatment, intolerance and poor expected results.
(2) Patients with moderate to severe SUI, which severely affects the quality of life.
(3) Patients with high quality of life requirements.
(4) Patients with pelvic floor functional lesions such as pelvic organ prolapse that require pelvic floor reconstruction should undergo anti-SUI surgery at the same time.
Only with a clear understanding of the pathophysiological changes behind different types of SUI can a reasonable treatment plan be formulated and patients can be properly treated. If we understand these complex pathophysiological changes, we will not simply dispose of patients with SUI, but should further understand the causes of urinary incontinence and make a more accurate assessment, and then choose a reasonable and effective surgical plan. Here, according to the different types of pathological mechanisms of SUI, the corresponding surgical approaches are introduced.
3.2.1 SUI due to subluxation of the bladder neck and proximal urethra due to laxity of the pelvic floor and periurethral support ligaments
3.2.1.1 Tension-free midurethral sling procedure
The new hypothesis of the mid-urethral hammock theory proposed by DeLancey in 1994, known as the “hammock hypothesis”, suggests that the increase in abdominal pressure is accompanied by a rise in mid-urethral closure pressure, which is one of the main mechanisms of urinary control. Such procedures include tension-free mid-urethral slinging, which can be broadly divided into two types: the retropubic route and the transapical route. At present, TVT (retropubic route) and TVT-O (trans-occlusive route) are more commonly used in China. Since its introduction, this type of procedure has become the only highly recommended treatment method in the SUI treatment guidelines for its stable efficacy, minimal injury and few complications, and is widely used in clinical practice.
(1) Trans-pubic route (TVT): Based on the “hammock hypothesis”, Ulmsten (1996) and others introduced the tension-free vaginal tape (TVT) for the first time. The polypropylene mesh band was placed in the mid-urethra, similar to the support mechanism of the pubourethral ligament, and the outer sheath of the mesh band was removed to form a large number of adhesions, which firmly fixed it in the exact position, strengthening the function of the pubourethral ligament and enhancing the “hammocking” effect of the suburethral vaginal wall. In addition, histological studies have shown that the metabolism of collagen in the paraurethral tissues is significantly enhanced after surgery, and that the linear accumulation of collagen due to the mesh band placement increases the support function around the mesh band. Long-term follow-up results show a cure rate of more than 80%. TVT has a cure rate similar to primary incontinence when treating recurrent incontinence; an efficiency of 85% for mixed incontinence; and an efficiency of 74% for patients with intrinsic sphincter defects. Common complications include bladder perforation, bleeding, difficulty in urination and sling erosion, etc. The main advantages of TVT compared with traditional surgery are precise and stable efficacy, small trauma, fast recovery, easy operation, wide application and few complications.
(2) Transobturator route (TVT-O): De Leval (2003) proposed a new transobturator tension-free vaginal tape (TVT-O) for the middle urethral sling. A curved puncture needle is passed through the vaginal wall around the descending pubic bone on both sides from the medial side of the closed foramen and out through the root of the thighs on both sides, and the sling is suspended from the puncture access. The recent efficiency is 84%-90%, which is basically comparable to TVT, but the long-term efficacy still needs to be further observed. TVT-O has the same surgical principle as TVT, but the puncture route is through the closed foramen instead of through the posterior pubic bone, which basically excludes the possibility of damaging the bladder or iliac vessels, but may increase the risk of vaginal injury. The rare serious complications are mainly sling vaginal erosion and closed-hole hematoma and abscess formation.
Comparison of the two procedures of TVT and TVT-O.
(1) Efficacy: It has been reported in the domestic literature that there is no significant difference between these two procedures for the treatment of SUI in terms of immediate and intermediate and long-term cure rates, significant rate and nullity.
(2) Complications: The internal rotation of the TVT puncture needle and the penetration too deep may cause damage to the bladder and urethra; while in TVT-0 the winged stall plate controls the puncture path strictly in the perineal area and limits the location of the puncture needle through the closed foramen without entering the posterior pubic space, avoiding important organs, blood vessels and nerves, and because of the protection of the pubic branch, the guide rod will not injure the anterior branch of the closed foramen artery and the clitoral vascular nerve bundle. Therefore, the complications of injury to the bladder, urethra and blood vessels in TVT-0 are theoretically less than in TVT. TVT has a higher incidence of complications such as bladder injury, bleeding, and also intestinal injury, injury to major blood vessels and necrosis; while TVT-0 has a higher incidence of complications in postoperative groin pain.
3.2.1.2 Repair of pelvic floor structures, tightening of lax ligaments and repositioning of the bladder neck
Based on the pathological mechanism of this type of SUI, the key to treatment is to repair the pelvic floor structures, tighten the lax supporting ligaments and reposition the bladder neck, such as Burch vaginal wall suspension, bladder neck sling, MMK, anterior vaginal wall repair and needle suspension.
(1) Burch vaginal wall suspension: The vaginal wall of the bladder base, bladder neck and proximal urethra are suspended by sutures on both sides of the Cooper’s ligament via the posterior pubic bone to lift the bladder neck and proximal urethra, thus reducing the mobility of the bladder neck. The procedure can be divided into two types of surgery: open and laparoscopic. Poorer visualization and less secure sutures than open surgery may explain the poorer outcome of laparoscopy. Laparoscopy has less bleeding, less injury, better tolerance and faster recovery than open surgery, but the operation takes longer, has higher technical requirements and is more expensive. The cure rate of primary surgery is more than 80%, and the cure rate of secondary surgery is basically the same as that of primary surgery, and the long-term follow-up shows that the effect of urinary control is long-lasting. the efficacy of Burch surgery is not affected when hysterectomy is performed at the same time, and the incidence of comorbidity is not increased. The main reasons for the efficacy of this procedure are: first, the suture is firmly anchored to Cooper’s ligament; second, the adipose tissue is sufficiently free to form more extensive adhesions. Common complications include dyspareunia, overactivity of the forceps, uterovaginal prolapse, and bowel hernia.
(2) Bladder neck sling: The bladder neck is suspended and anchored from below the bladder neck and proximal urethra in the suprapubic direction and fixed to the anterior rectus abdominis sheath to change the angle of the bladder urethra, fix the bladder neck and proximal urethra, and produce a slight compression effect on the urethra. The sling material is mainly self-material, but can also be allografts, allografts or xenografts and synthetic materials. The efficacy is more certain, with an average rate of 82%-85% for initial surgery, 64%-100% for reoperation, and an average cure rate of 86%. It can be applied to patients with all types of SUI, especially type I and type II SUI with better results. Common complications include dyspareunia, overactivity of the detrusor muscle, bleeding, urinary tract infection, urethral necrosis and urethrovaginal fistula.
(3) Marshall-Marchetti-Krantz (MMK) procedure: The bladder base, bladder neck, urethra and anterior vaginal wall on both sides of the urethra are sutured to the symphysis pubis periosteum in order to restore the bladder neck and proximal urethra to their normal position, reduce the mobility of the vesicourethra and restore the vesicourethral angle. This procedure can be done openly or laparoscopically. Disadvantages: First, the efficacy is lower than that of the Burch procedure and mid-urethral sling; second, there are many complications, with an overall complication rate of 22% and the incidence of pubic osteomyelitis can exceed 5%.
(4) Anterior vaginal wall repair: repair of the anterior vaginal wall to enhance the supporting tissue of the bladder floor and proximal urethra, to reposition the bladder and urethra, and to reduce their mobility. Main advantages.
(i) It can treat pelvic organ prolapse and perform vaginal reconstruction at the same time, and can be an option for patients with SUI with significant vaginal bulge.
(ii) The complication rate is low, the incidence of overactivity of the detrusor muscle is less than 6%, the length of hospital stay and bleeding is less compared to vaginal wall suspension, and there are no significant distant voiding disorders. Disadvantages.
①Long-term efficacy is poor, with a recent urinary control rate of 60%-70% and a 5-year effective rate of about 37%.
(ii) It can easily lead to nerve damage. Anatomical and histological studies have shown that the autonomic nerves innervating the bladder neck and proximal urethra are located close to the subvesical vascular plexus and enter the urethral sphincter near the anterolateral vaginal wall at 4 and 8 o’clock. This procedure may result in denervation of the urethral sphincter due to extensive separation of the anterior vaginal wall.
(5) Needle suspension: A small incision is made on the pubic bone of the abdominal wall and a fine needle is punctured immediately behind the pubic bone to enter the vagina. The anterior vaginal wall on the side of the bladder neck is lifted with a suspension wire and suspended and fixed on the rectus abdominis muscle or pubic bone in order to pull the anterior vaginal wall toward the abdominal wall, elevate and fix the bladder neck and proximal urethra, correct the vesicourethral angle, and reduce the mobility of the bladder neck and proximal urethra. Surgical modalities include Pereyra and Stamey procedures. The main advantages are simple operation, minimal trauma, and good patient tolerance. Disadvantages.
①Long-term efficacy is poor. The efficiency of puncture suspension is 43%-86%, but the long-term outcome is poor, with a subjective success rate of 74% at 1-year follow-up and an efficiency rate of 17% at 2.5 years. The main causes of urinary incontinence recurrence include overactive urethra, defective function of the intrinsic urethral sphincter, and overactive forcepsis muscle.
② Complications are more frequent. The perioperative complication rate is 48%, and there is also a risk of osteomyelitis of the pubic bone with suspension fixation to the pubic bone.
③It is not suitable for those with bladder bulge. This procedure is simple and less invasive, but its short-term and long-term efficacy is poor, and there are many complications, so its application is limited.
3.2.2 SUI due to decreased function of the intrinsic urethral sphincter and reduced urethral mucosal closure
The treatment of patients with SUI due to this cause is to use physical methods to replace the decreased function of the intrinsic urethral sphincter and to increase the sealing function of the urethral mucosa to achieve urinary control. Commonly used procedures are injection therapy and artificial urethral sphincter. Both of these procedures require the patient to have stable forceps and no proximal urethral hypermobility of the bladder neck.
3.2.2.1 Injection therapy: Under direct endoscopic vision, a filler is injected into the submucosa of the internal urethral orifice to narrow and elongate the urethral lumen to increase urethral resistance, lengthen the functional urethral length, and increase the closure of the internal urethral orifice for urinary control purposes. Injection therapy mainly produces therapeutic effects by increasing the ability of urethral closure. Commonly used injectable materials include silicone granules, polytetrafluoroethylene and carbon-encapsulated zirconium beads. Other available injectable materials include sodium cod liver oil acid, glutaraldehyde cross-linked bovine collagen, autologous fat or cartilage, sodium hyaluronate/polyglycolic anhydride and myogenic stem cells. The advantages are minimal trauma and low incidence of serious complications. Disadvantages.
(i) Limited efficacy, with 30%-50% near-term efficacy and poor long-term efficacy.
②Some complications, such as short-term voiding disorders, infection, urinary retention, hematuria, possible allergy to individual materials and migration of particles, etc. Serious complications are urethrovaginal fistula. Because of the poor efficacy, especially in the long term, it can be used selectively in patients with type I and type III SUI with less bladder neck mobility, especially with severe comorbidities who cannot tolerate anesthesia and open surgery.
3.2.2.2 Artificial urethral sphincter: A cuff of the artificial urethral sphincter is placed in the proximal urethra to produce a circular compression of the urethra. The application in the treatment of SUI has been reported relatively rarely and is mainly used in patients with type III SUI. Patients with significant pelvic fibrosis, such as multiple surgeries, urinary extravasation, and pelvic radiation therapy are not suitable for this procedure. The advantage is that it has definite efficacy in type III SUI and long-term urinary control can be obtained. The main disadvantage is that it is expensive and has a high complication rate. Common complications include mechanical failure, infection, urethral erosion, urinary retention and recurrence of urinary incontinence, and the need to remove the artificial urethral sphincter if necessary.
The procedure and surgical modality should be carefully selected when the following conditions exist.
(1) If the patient has mixed type of sexual incontinence mainly urge incontinence, bladder behavior therapy, pelvic floor muscle training and anticholinergic drug therapy should be taken first, and if the symptoms improve significantly and the patient is satisfied, the patient may be treated without surgery. If the above treatment measures are not effective, suggesting that the patient has mixed type of urinary incontinence mainly SUI, surgical treatment can be performed.
(2) In the case of SUI combined with pelvic organ prolapse, the following treatment principles are recommended.
(1) Those with symptoms of SUI but pelvic organ prolapse without surgical treatment can be treated as SUI.
(2) For those with SUI symptoms and pelvic organ prolapse requiring surgical treatment, SUI surgery can be performed while repairing pelvic organ prolapse, with a cure rate of 85%-95%.
(3) For patients with SUI combined with urethrovaginal fistula, urethral erosion, intraoperative urethral injury and/or urethral diverticulum, all synthetic slings cannot be used, and autologous fascia or biological slings are recommended.
(4) When SUI is combined with reduced contractility of the forced urinary muscles, the following principles of management are recommended.
(1) If the maximal detrusor systolic pressure is >15cmH2O, there is no significant residual urine volume, and there is usually no significant abdominal pressure to urinate, non-surgical treatment can be performed first, and if it is ineffective, SUI surgery should be considered, but the possibility of intermittent catheterization at home should be informed before surgery.
(2) SUI surgery is not recommended when the maximum detrusor systolic pressure is ≤15cmH2O, or when there is a large residual urine volume, or when the usual is obvious abdominal pressure voiding.
(5) When SUI is combined with bladder outlet obstruction, bladder outlet obstruction should be released first, and SUI should be evaluated and treated after stabilization. for patients with frozen urethra and urethral stricture, surgical treatment to release bladder outlet obstruction and SUI can be performed at the same time.
4. Outlook
With new concepts and improved techniques, there will be more and more attention and understanding of SUI, and the widespread use of minimally invasive surgical methods will lead to faster development of the field. Myogenic stem cells (MDSC), which has recently become a research hotspot, has received much attention because of its multi-differentiation potential. 2004 Strasser first reported the clinical results of MDSC injection for the treatment of SUI, and the results were surprising. after 1 year of follow-up, all 5 female patients treated with autologous myogenic stem cell injection remained symptom-free. One study found that MDSC injection into the bladder wall and urethra resulted in a large number of viable MDSC and formed muscle fibers with long-lasting effects. mitterberger [15] et al. performed MDSC injection in 20 female patients with SUI and the results were 18 cured and 2 improved at 1 year follow-up; 16 cured, 2 improved and 2 lost at 2 years follow-up. Although MDSC injection has the advantages of longer duration of action, less immune response and less trauma, this technique is still in the research stage and has a promising future in the treatment of female SUI. The use of MDSC injection as a recent research hotspot has opened up a new field for the treatment of SUI, creating new hope for SUI treatment with its unique advantages.