To evaluate the feasibility and therapeutic effect of transvesicle laparoendoscopic single-site surgery (LESS) for repair of vesicovaginal fistula (VVF) with a homemade single-port device.

From January 2012 toMarch 2018, 42 patients underwent transvesicle LESS VVFs repair. The bladder wall was cut open, and single-port access was placed into bladder cavity. Ureteral catheters were inserted into the bilateral ureter to mark and protect the ureter through urethra and with the help of pliers under laparoscopy. Another ureteral catheter was insterted into the bladder from vaginal fistula as the guideline of surgical removal of scar. After resection of of scar tissue around fistula canal, the anterior vaginal wall and bladder wall were isolated sufficiently. Then the vaginal wall and bladder wall were sutured separately. In addition to, we analyzed the learning curve for transvesicle LESS for repair VVF.

The basic data of transvesicle LESS for repair of VVF. 
Firstly, we counted the basic data of 42 VVFs patients. (Table. 1) The mean age of them was 44.6 years old. The mean fistula size was 0.9±0.5cm. The etiology of these 42 VVFs consist of 21 (50.0%) cervical cancer, 15(35.7%)myoma, 3(7.1%) adenomyosis , 1(2.4%) endometrial cancer, 1(2.4%) ureterostenosis, 1 (2.4%) cesarean.  The VVFs were caused by panhysterectomy in 26(61.9%), radical hysterectomy in 15(35.7%) and ureteral reimplantation in 1(2.4%）. Three patients received pelvic radiation therapy 2 or 3 months before surgery. The surgery of these 42 patients were the first time, and the location of the fistula was described in Table 1.  
The operative and postoperative details of transvesicle LESS for repair of VVF.
Operative and postoperative details are presented in Table 2. The mean time for single-port construction and establishment of transvesical single-port access were 4.2±1.6min and 4.4±1.2min, respectively. The mean operative time was 31.3±12.9min. Transvesicle LESS were completed successfully for 41 patients. There were no patients conversion to laparotomy, but one patient conversion to transabdominal approach. The reasons for conversion was two large fistulas. 
The mean volume of blood loss was 34.8±51.3ml, no patient needed blood transfusion. All patients was not filled anything between the bladder wall and vaginal wall. VVFs were successfully repaired in 33 (78.6%) patients after the first surgery. Nine patients  were performed secondary surgery because VVF recurrence.  Urine still flowed into the vagina in two patients of them after secondary surgery. The reason of the two patients failed the second transvesicle LESS VVF repair were: one patient had sex early after VVF repair; one patient had a long term of pelvic radiation therapy before VVF repair. The mean length of hospital stay was 7.4±2.2d. Symptomatic bladder spasms, urinary tract infections(UTIs) and ileus were the relatively common postoperative complications. Patients experienced postoperative UTIs 7.1% and symptomatic bladder spasms 11.9%. The patients who developed symptomatic bladder spasms were managed by anticholinergics administered orally for 3-4weeks; patients who developed UTIs were managed by antibiotics orally for 2 weeks. All patients who developed symptomaticbladder spasms or UTIs had completely symptomatic remission at the last follow-up evaluation. No patient developed ileus. Abdominal wound infection, peritonitis, pelvic abscess, or ureteral injuries was not discovered. But the wound of 1 patient closed up slowly because of fat liquefaction.
The learning curve of transvesicle LESS for repair of VVF.
For initial analysis, the 42 patients were divided into 7 groups to evaluated the learning curve for transvesicle LESS for repair VVF. Each group contained 6 patients. Therefore, we evaluated these cases six by six. With this approach, we have found the point of significant change in the shortening of the operation time in group 6. The average operation time was 25.3 min for cases 30-36 and steady after these cases, indicating that a learning curve plateau in terms of operation time was reached after this point and continues through the rest of the cases.

There were two fistulas in the sixth patient, so the  operation time was longer than others patiens obviously.

Transvesicle LESS VVFs repair is feasible and effective, but is difficult than conventional laparoscopic surgery. Single-port multi-channel device and laparoscopic instruments need further improvements.

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