Hypothesis / aims of study
For patients with stress urinary incontinence (SUI) and vaginal relaxation, mid-urethral sling (MUS) could have a limited improvement on postoperative sexual function. We firstly aimed to demonstrate a modified posterior colporrhaphy (MPC) technique and evaluate the outcomes of it combined with MUS for these patients.
Study design, materials and methods
This prospective, randomized, interventional study was conducted from October 2021 to March 2023. in 60 female patients diagnosed with SUI and vaginal laxity. The work has been reported in line with CONSORT criteria. Local ethics committee approval was obtained, and written informed consent was obtained. Patients were followed at 6 months postoperatively. The primary outcome was the assessment of improvement in sexual function using ICIQ-SF, I-QOL, and PISQ-12 questionnaires. Secondary outcomes were the quality-of-life assessments in SUI symptoms (ICIQ-SF, I-QOL, and PISQ-12 questionnaires), surgery success rate, and the assessment of adverse events. The success of MUS surgery was defined by a negative CST in the follow-up period. The MPC procedure was defined as a success if the patient was satisfied with sexual life in the follow-up period.
Based on previous data, we expected 35% sexually active patients had sexuality improvement for the MUS alone surgery. For the primary outcome, assuming 80% patients would report sexuality improvement after the MUS + MPC surgery, with a 1-sided type I error of 0.05 and 90% power, 42 subjects (21 per treatment arm) were needed to detect noninferiority of MPC + MUS to MUS control. Given a potential 20% loss to follow-up rate was calculated. A minimum of 50 subjects (25 per treatment arm) were to be enrolled. Data analysis was performed using intent-to-treat (ITT) methods. Sixty enrolees were finally enrolled, and they were randomised into two groups using randomly assigned sealed envelopes: 30 patients received MUS + MPC surgery and 30 MUS alone. All surgeries are being conducted by a single surgeon (Hong S.) in our centre.
Surgical technique was described as follows: After the anti-incontinence surgery, MPC was performed on 30 patients. The posterior vaginal wall was infiltrated with about 100ml water to form a water sac in the rectovaginal septum (Fig. 1A). Next, the dissection was conducted with a horizontal incision (Fig.1 B). Then separate the rectovaginal septum along the water sac, separating the full thickness of the posterior vaginal wall from its deeper layers. Starting from the vicinity of the posterior vaginal fornix, suture both lateral sides of the posterior vaginal wall horizontally to form a plication on the fascia extending to the vagina, thus tightening the diameter of the vagina (Fig.1 C). Lastly, repair and lift the perineum, and close the incision (Fig.1 D). After the MPC surgery, only two fingers can be inserted into the entire length of the vagina.
Student's t-test and Mann–Whitney U test were used to evaluate the baseline characteristics between group. Repeated measures analysis of covariance was conducted to examine differences between groups with means (± SE).
Results
Twenty-six enrolled patients in the MUS plus MPC group and 25 in the MPC only group completed their postoperative assessment. The two populations had similar preoperative characteristics. The mean age of patients showed no significant difference among MUS+MPC and MUS-only group (45.9 ± 7.5 vs 47.6 ± 6.1 yr). The mean follow-up time was similar (9.6 ± 3.0 vs 9.7 ± 2.8 mo). The preoperative scores of FSFI, PISQ-12, VLQ, ICIQ-SF, and I-QOL showed no significant differences (22.0 ± 2.7 vs 22.8 ± 2.8, 31.0 ± 3.5 vs 32.2 ± 3.5, 2.3 ± 0.6 vs 2.6 ± 0.5, 17.2 ± 2.9 vs 16.3 ± 2.8, and 30.6 ± 10.0 vs 32.4 ± 9.8, respectively, P>0.05 for all) (mean ± standard deviation). The primary outcome showed the improvement in FSFI, PISQ-12, and VLQ scores were all significantly higher in the MUS+MPC group than the MUS-only group (30.0 ± 0.5 vs 24.8 ± 0.5, P < 0.001; 37.3 ± 0.7 vs 35.0 ± 0.8, P < 0.05; and 5.2 ± 0.1 vs 2.7 ± 0.1, P < 0.001, respectively) (mean ± SE). The secondary endpoints indicated that ICIQ-SF and I-QOL scores between the two groups both improved, without a significant difference (2.1 ± 0.8 vs 2.0 ± 0.8, P > 0.05; 91.9 ± 2.8 vs 93.4 ± 2.8, P > 0.05) (mean ± SE). The success rate of the MUS was similar in both groups. The success rate of MPC was 100%. The overall postoperative complication rates were not different between the two groups. No major complication in either group were noted.
Interpretation of results
The results demonstrated that both groups showed increase in the sexual function, while the improvement in MUS+MPC group was significantly greater than the MUS-only group. The secondary outcomes showed that two groups reported a similar improvement of SUI-related quality of life. Unlike most conventional vaginal constriction surgery, which only repair the entrance or the lower two-thirds of the vaginal wall [1-3], we reconstructed the whole length of the posterior vaginal wall. We made an 8-12 cm long plication extending to the vagina from the level of the hymen margin to the posterior vaginal fornix, which could help achieve great sexual gratification in both men and women [1], and also help to prevent air from entering the vagina, avoiding embarrassing sounds during sexual intercourse. Meanwhile, we reconstructed the rectovaginal septum to form a plication without making incisions in the vaginal mucosa, thus could help improve the sensation and lubrication of the vagina [3].