Fistula in ano

　　Fistula in ano is a common disease in women. Historically, delivery injuries have been the main cause of fistula in ano, often leading to lifelong urinary incontinence. The following are the causes of fistula in ano:

　　1. Prolonged compression of the bladder by the fetal head during delivery or dystocia, causing tissue necrosis and ulceration leading to fistula.

　　2. Injuries caused by pelvic surgery or vaginal surgery.

　　3. Bladder tumor invasion of the vagina, or cervical tumor infiltration into the bladder.

　　4. Complications caused by radiotherapy for bladder or cervical tumor.

　　5. Improper use of pessary, caused by long-term compression.

　　In developed countries, surgical injury, especially gynecological hysterectomy, is the main cause of vesicovaginal fistula, followed by other pelvic surgeries and radiotherapy for pelvic and cervical malignant tumors. In developing countries, vesicovaginal fistula caused by childbirth injury is still a common cause.

　　An abnormal fistula between the bladder and vagina is called a vesicovaginal fistula. The clinical manifestations of vesicovaginal fistula are the continuous leakage of urine. The occurrence of fistula can appear at the time of injury, or within a few days and weeks after injury. Vesicovaginal fistula is prone to the following diseases.

　　1. Bleeding and hematoma

　　All kinds of vesicovaginal fistula repair surgeries are difficult due to small surgical fields, severe adhesions, difficulties in exposure, accidental injury to surrounding larger blood vessels, or difficulty in hemostasis due to hard scar tissue around, which can cause continuous bleeding during surgery or postoperative hemorrhage forming a hematoma. Therefore, the stripping of tissue must be careful and detailed, and cannot be done in large areas. Any bleeding point should be hemostatized thoroughly. If there is oozing hemorrhage that cannot be stopped, saltwater cotton pads, hemostatic gauze, or Monsell solution can be used to help hemostasis. The suture should be done carefully, without leaving any gaps to prevent oozing hemorrhage.

　　2. Infection

　　Patients with vesicovaginal fistula all have varying degrees of urinary tract infection. After the repair of the fistula, the wound surface is still in contact with polluted urine, and the tissue damage caused by surgery can lead to an increase in inactive tissue or foreign body retention in the wound due to the use of multifilament silk thread for suture. All these factors can lead to the infection and suppuration of the repaired scar, resulting in poor healing and the recurrence of the disease. The operation must meet the sterile requirements, and the tissue damage should be minimized. The use of monofilament atraumatic suture thread, good drainage to keep the bladder empty, and these are the main measures to prevent the failure of fistula repair.

　　3. Urinary incontinence

　　The urinary bladder neck fistula is extremely difficult to repair due to tissue defect, and even if the repair is successful, urinary incontinence is likely to occur after surgery. However, the surgery to reconstruct the continuity of the bladder and urethra using the method of repairing vaginal defects is more likely to be successful. In most cases, the defect of the bladder neck reaches the level of the pubic symphysis. Due to the reconstruction of the bladder neck during surgery, there was no case of urinary incontinence. For those cases where there is no defect in the bladder neck, urinary incontinence due to long-term disuse of the internal sphincter, relaxation of the bladder neck, or short urethra after surgery can be prevented by fixing the bladder neck to the pubic periosteum and performing a urethral lengthening procedure. This can prevent the occurrence of stress urinary incontinence.

　　4. Ureteral stenosis

　　In cases where the ureteral orifice opens at the edge of the diseased orifice, improper treatment can lead to stenosis and closure of the orifice after surgery. In such cases, a ureterovesical transplantation can be performed, but this operation is complex and not only increases the patient's burden but may also result in ureteral reflux or the formation of a new urinary fistula. To reduce the occurrence of ureteral reflux, a 'U' shaped incision about 1.5cm long can be made around the ureter for half a circle, with the distal end of the ureter freed for about 1.5cm. The incision mucosa is sutured with fine silk thread, making the distal end of the ureter protrude like a nipple into the bladder. This method is simple, easy to perform, and effective.

　　5、输尿管损伤

　　5. Ureteral injury

　　What are the typical symptoms of vesicovaginal fistula

　　How to prevent vesicovaginal fistula

　　The main cause of vesicovaginal fistula is bladder injury. In view of the main causes of bladder injury, the preventive measures are as follows:

　　1. Continuously improve the quality of obstetrics, do pre-natal examinations well, and early detect pelvic stenosis and malpresentation. Strengthen the management of women's health care work, strive to achieve scientific delivery, prevent dystocia and prolongation of the second stage of labor, and avoid bladder distension.

　　2. Routine vaginal examination is performed after difficult labor surgery, and if there is suspicion of bladder compression or injury, a urinary catheter is left in place to empty the bladder, improve local blood circulation, and prevent the formation of a fistula.

　　3. For those with uterine rupture, check for injury to the ureter and bladder, and handle it promptly.

　　An abnormal fistula exists between the bladder and the vagina, known as vesicovaginal fistula. The clinical manifestations of vesicovaginal fistula are the continuous leakage of urine. The occurrence of vesicovaginal fistula can appear at the time of injury, or within several days and weeks after the injury. The examination of vesicovaginal fistula includes the following items:

　　1. Methylene blue test:

　　The purpose is to examine microscopic fistulas that are difficult to identify by the naked eye, such as small multiple fistulas, or fistulas in scars, or to differentiate between vesicovaginal fistula and ureterovaginal fistula.

　　2. Indocyanine green test:

　　The purpose is to diagnose ureteral fistula. For those who have no blue liquid discharge from the vagina after the methylene blue test, 5ml of indocyanine green can be injected intravenously, and 5 minutes later, observe whether there is blue liquid discharge from the vagina. If there is, it can be diagnosed as a ureterovaginal fistula. This method can also be used to diagnose congenital ureteral orifice ectopia in the vagina.

　　3. Cystoscopy:

　　Generally, the above examination can determine the location, size, bladder capacity, and mucosal condition of the fistula. High fistulas can be localized with the help of cystoscopy and the relationship between the fistula and the ureteral orifice can be clearly identified as a reference for repair.

　　4. Intravenous Pyelography:

　　It helps to clarify the side, location, and renal function of the injured ureter, as well as the presence of stricture, dilation, or obstruction in the injured ureter. The method is to inject sodium diatrizoate intravenously, perform X-ray imaging of the kidney, ureter, and bladder, and make a diagnosis based on the contrast situation.

　　5. Renal Scintigraphy:

　　The purpose is to understand the renal function and the patency of the upper urinary tract, such as the stricture or obstruction caused by ureteral fistula, which can lead to a decrease in renal function or kidney atrophy, or the loss of renal function on the affected side.

　　Patients with vesicovaginal fistula should drink plenty of water to increase urine output, eat foods rich in vitamins, eat light, low-protein, and low-fat foods, pay attention to nutrition, and avoid刺激性 food.

　　Vesicovaginal fistula is a common disease in women. Historically, delivery injuries have been the main cause of vesicovaginal fistula, often leading to lifelong urinary incontinence. Vesicovaginal fistula can be treated with conservative and surgical treatment. Today, I will introduce to you the methods of conservative treatment:

　　Once a vesicovaginal fistula is diagnosed, those who have the condition should first try conservative treatment. For those who develop fistulae soon after childbirth or have small fistulae, surgical treatment is not necessary. An indwelling catheter can be left in place for about 10 days, and it can heal spontaneously.

　　1. Continuous urinary drainage with an indwelling catheter:

      Although the success rate of this conservative treatment has not been fully proven by literature, patients with very small fistulae may be cured. Antibiotics should be added when using this method to control possible infections, and oral anticholinergic drugs should be taken to control possible bladder spasm.

　　2. Vaginal or bladder electrocoagulation:

      The edge of the electrocoagulation fistula is coagulated, combined with the continuous drainage of urine through the indwelling catheter, which can seal small fistulae. Stovsky (1994) reported that 17 cases of vesicovaginal fistula, in which several fistulae were cured with this method with a diameter of about 1-3mm (73%). The specific method is to use pediatric electrodes and the smallest electrocoagulation current, electrocoagulate the epithelium around the fistula, and leave the Foley catheter in place for 2 weeks after electrocoagulation. Caution must be exercised when using this method, otherwise, it may反而扩大了瘘口.