To investigate the clinical efficacy of transconjunctival tension-free vaginal sling (TVT-O) in the treatment of female stress urinary incontinence (SUI). Methods Two patients diagnosed with severe SUI by clinical examination were retrospectively analyzed. The ages ranged from 37 to 66 years, with an average of 51.5 years. The duration of disease was 20-30 years, with an average of 25 years. Results Operative time was 15~25 min, average 20 min, intraoperative bleeding was <30 ml. catheter was removed 1~2 d after surgery, and satisfactory urinary control was obtained in both cases. one case showed soreness at the root of the thigh, no special treatment was done, and the symptoms resolved on their own after 3 days. There were no cases of bladder injury or perforation, sling rejection or wound infection and vaginal perforation, and no cases of dyspareunia or urinary retention. The average postoperative hospital stay was 3.5 d. The entire group was followed up and no recurrence of incontinence or related complications were observed. Conclusion TVT-O is simple, minimally invasive, with few comorbidities and positive efficacy, and is a safe and effective method for treating SUI in women. [Keywords] Urinary incontinence; stress; tension-free vaginal sling; closed-hole midurethral suspension The efficacy of treating female stress urinary incontinence (SUI) has been universally recognized. The most commonly used suspension procedure is the tension-free virginal tape (TVT). Most of the slings (including TVT, Sparc, etc.) are associated with the risk of bladder injury during surgery. The transobturator vaginal tape-inside-out (TVT-O) is a modified sling procedure that eliminates the need for cystoscopy and is more simple, minimally invasive, and has fewer complications. Our hospital used TVT-O from February 2006 to November 2006 to treat 2 cases of female stress urinary incontinence with satisfactory results, which are reported as follows: Data and methods I. Clinical data Two cases in this group. The age ranged from 37 to 66 years, with an average of 51.5 years. The duration of the disease was 20-30 years, with an average of 25 years. 2 cases had no history of pelvic surgery. The clinical manifestations were severe SUI. 2 patients were examined preoperatively: normal bladder compliance, no residual urine; bladder volume 380-460 ml, average 420 ml. 2 patients had positive induction test and bladder neck lift test. The surgical procedure was an "inward and outward approach via a closed-hole route". Vaginal irrigation was performed for 3 days before surgery. The first horizontal line was drawn with a marker at the urethral orifice, and the second horizontal line was drawn 2 cm above the parallel line, and the TVT-O outlet on both sides was marked 2 cm from the intersection of the line and the pubic bone branch on both sides. A F18 balloon catheter was left in the urethra to empty the bladder. A 1.0 cm longitudinal incision is made in the anterior vaginal wall at 1.0 cm from the external urethra to separate the vaginal wall from the urethra, and through this incision, the anatomical scissors are held to separate sharply and bluntly on both sides. A special TVT-O puncture guide needle (Johnson & Johnson Gynecare TVT closed-hole system) is used to enter through the tunnel on one side, exit the guide slot, turn the handle and continue to feed the needle, break through the closed-hole membrane, pierce vertically to the pre-determined TVT-O exit mark, poke the skin with a sharp knife, lead the puncture needle out of the skin, clamp the tip of the puncture needle with a vascular clamp, and exit the handle. The same method is used to puncture the contralateral side to avoid twisting of the sling. A scissor tip is placed between the urethra and the sling, the sling is tightened after satisfactory adjustment of the elasticity of the sling, the sling sheath is withdrawn and the excess sling is cut away from the skin. 4-0 VICIO sutures are placed on the anterior vaginal wall incision and the vagina is filled with a piece of iodophor gauze. Cystoscopy is not required. Appropriate antibiotics were applied to prevent infection. The patient can eat 6h after surgery. The catheter was removed 1~2d postoperatively and urination was tried. Avoid strenuous exercise and sexual life for 1 month after surgery. III. Postoperative follow-up Postoperative follow-up 1~10 months, average 5.5 months. Postoperative outpatient follow-up or telephone inquiry was used to follow up the efficacy. The follow-up included the presence of recurrence of urinary incontinence, the presence of urinary fistula, recurrent urinary tract sensation when and sling urethral erosion and other comorbidities and postoperative urinary control. Results: The surgery was completed successfully in both cases. Intraoperative bleeding was <30 ml, and no cystoscopic observation was required. The catheter was removed 1~2d after surgery, and satisfactory urinary control was obtained in both cases with negative provocation test. 1 case showed soreness at the root of the thigh without special treatment, and the symptoms resolved on their own after 3 days. There were no cases of bladder injury or perforation, sling rejection or wound infection and vaginal perforation, and no cases of dyspareunia or urinary retention. The average postoperative hospital stay was 3.5 d. The whole group was followed up and none of them had recurrence of urinary incontinence or related complications. Discussion The International Continence Control Society (ICS) states that stress urinary incontinence (SUI) is characterized by uncontrollable urine leakage when abdominal pressure is increased by exertion, sneezing, coughing, etc. In Western countries, the overall prevalence of SUI is as high as 30-60%. SUI occurs in middle-aged and older women and is a result of urinary dysfunction caused by relaxation of the musculofascial tissue of the pelvic floor, altered anatomical position of the bladder and urethra, and reduced urethral resistance. In addition, lower estrogen levels, lack of intrinsic urethral sphincter, and a shorter female urethra are also important factors that predispose women to SUI, which has a significant impact on the patient's psychology, daily life, work, social activities, and even sexual life. Based on the "hammock hypothesis" proposed by Delancey in 1994, which states that the anterior vaginal wall, intrapelvic fascia, and anal levator muscle form a hammock-like structure to support the urethra, the treatment of SUI in women should focus on rebuilding the urethral support tissue. The principle of TVT for female SUI is that when the patient's abdominal pressure increases, the sling passively stops the downward-moving urethra, causing the internal urethral pressure to increase and exceed the bladder pressure, preventing urinary overflow. This procedure is being promoted rapidly because it is simpler and less invasive than previous treatments and has a shorter hospital stay. However, as this procedure continues to spread, there are increasing reports of complications, such as bladder perforation, nerve, vascular, and bowel injuries. Because the procedure requires crossing the retropubic space, it should be used with caution in patients with a history of pelvic surgery to avoid damage to the intestines or pelvic organs. In 2001, Delorme first reported a modified transconjunctival urethral sling, TOT, which is a urethral suspension with a skin entry through the root of the thighs bilaterally and an incision around the closed hole out of the anterior vaginal wall. In 2003, de Leval proposed the "inside-out" transconjunctival urethral sling technique, TVT-O, which involves a curved arched urethral sling. -TVT-O, in which a curved needle is inserted through the anterior vaginal wall incision around the pubic bone branch on each side, through the medial aspect of the closed foramen, and out through the root of the thighs on both sides. Studies have shown that TVT-O can minimize urethral and bladder injury, with almost no possibility of arterial injury to the foramen occulans, and the efficacy is similar to that of TVT. The average operative time of TVT-O in our group was 20 min, with minimal bleeding and without cystoscopic observation. There were no complications such as bladder perforation, sling rejection and vaginal perforation and postoperative difficulty in urination, and the results were similar to those reported in the literature. Mild discomfort at the root of the thigh occurred in one case in this group, probably due to muscle spasm caused by stimulation of the relevant muscle tissue during the puncture, which required no special treatment and resolved on its own after bed rest. Our experience in the operation protocol of TVT-O is that: ① when incising the anterior vaginal wall, beware of cutting too deep and damaging the urethra, while separating the tissue of the anterior vaginal wall too thin will affect the local healing; ② when establishing a tunnel to the upper side of the anatomical scissors, the dilated tunnel should not be too wide and should be controlled at a diameter of about 0.5 cm; ③ when turning the handle to puncture, the puncture needle should be placed close to the pubic bone branch from the upper part of the closed foramen in order to avoid ④Adjusting the tension of the sling is a key step to the success of the operation, and it is generally appropriate to maintain a width of about 1 cm between the sling and the urethra, which is roughly equivalent to the width of the head of the anatomical scissors, rather loose than tight. The results of this group suggest that TVT-O has the advantages of simple surgery, small trauma and light complications. As long as the procedure is performed in strict accordance with its protocol, complications are minimal. The fact that TVT-O does not require cystoscopy makes it more beneficial for obstetricians and gynecologists and medical units without cystoscopy to perform the procedure. the feature that TVT-O does not pass through the retropubic space extends the indications for the procedure, and a history of pelvic surgery is no longer a contraindication to the procedure. Therefore, TVT-O is worthy of clinical promotion. However, the number of cases and follow-up time in this group are limited, and the long-term efficacy remains to be further observed.