Stress urinary incontinence (SUI) affects the quality of life in women.Therefore, suburethral sling is needed in this group of patient. However, for patients with SUI combined with detrusor underactivity (DU), the benefit of suburethral sling is still controversial. The aims of the study are to survey the outcomes of patients with both SUI and DU after suburethral sling operation, to assess the associated predictive factors, and to evaluate the long-term satisfaction.

The medical records of 71 female patients who were treated with suburethral sling for SUI and DU between 1990 and 2017 were retrospectively analyzed. Patients were categorized into three subgroups based on the etiology of SUI and DU, including spinal cord injury (SCI) or stroke (n=9), pelvic radiotherapy with/without radical hysterectomy (n=27), and others cause of DU (n=35). For the primary outcome, we analyzed the proportion of patients in three different outcomes, including: (1) improved incontinence without clean intermittent catheterization (CIC), (2) absence or improved incontinence with CIC and (3) no improvement in incontinence, based on whole sample (n=71) and different subgroups. For the secondary outcome, chi-square test and multivariate logistic regression were used to analyze the selected parameter of video urodynamics; age and number of vaginal spontaneous delivery to find the predictive factors for three types of outcome mentioned above. The incontinence impact questionnaire-7 (IIQ-7) and urogenital distress inventory-6 (UDI-6) were used to analyze patients’ satisfaction before the anti-incontinence operation, and at 6 months and 12 months after the operation.

After operation, out of 71 patients, 39 (54.9%) had improvement in incontinence without CIC, 15 (21.1%) had absence or improvement in incontinence with CIC, and 17 (23.9%) had no improvement in incontinence. In the patients of SCI or stroke, 2 (22.2%) had improved incontinence without CIC, 4 (44.4%) had absence or improved incontinence with CIC, and 3 patients (33.3%) had no improvement in incontinence. In the patients with pelvic radiotherapy / radical hysterectomy, 14 (51.9 %) had improved incontinence without CIC, 6 (22.2%) had absence or improved incontinence with CIC and 7 (25.9 %) had no improvement in incontinence. In the third group patients, 23  (65.7 %) had improved incontinence without CIC, 5 (14.3 %) had absence/improved incontinence with CIC, and 7 (20%) had no improvement in incontinence. There was no significant difference between three subgroups and three type outcomes (P= 0.181). (Table 1)  In patients with a measurable voiding detrusor pressure (Pdet) ≥ 10 cmH2O or <10 cmH2O, there was no significant difference in three type outcomes between them (P=0.062). And in patients with Pdet ≥ 15 cmH2O or <15 cmH2O, there was no significant difference in three type outcomes between them (P= 0.05). However, there was a significantly higher proportion (72.7%) of patients with Pdet ≥ 15 cmH2O which had improved incontinence without CIC (P= 0.043). There was a significantly lower proportion (4.54%) of patients with Pdet ≥ 15 cmH2O who had absence/improved incontinence with CIC (P= 0.022). In patients with abdominal pressure (Pabd) ≥ 37 cmH2O or < 37cmH2O, there was no significant difference in three type outcomes between them (P=0.071). But there was a significantly higher proportion (66.7%) of patients with Pabd < 37 cmH2O who had improved incontinence without CIC (P= 0.037). There was a significantly lower proportion (12.8%) of patients with Pabd < 37 cmH2O who had absence/improved incontinence with CIC. The mean of UDI-6 at the time of pre-operation, 6 months after operation and 12 months after operation were 8.6, 4.8 and 4.4, respectively. There was significantly decreased UDI-6 score between pre-operation and 6 months after operation (P= 0.00) and 12 months after operation (P=0.00). The mean of  IIQ-7 at the time of pre-operation, 6 months after operation and 12 months after operation were 10.13, 4.38 and 4.18, respectively. There was significant decrease of IIQ-7 score between pre-operation and 6 months after operation (P= 0.00) and 12 months after operation (P=0.00). In multivariate logistic regression, analysis showed the only statistically significant difference in Pdet <10 cmH2O and <15 cmH2O was Pabd (P=0.003 and P=0.000 respectively). In patients with Pabd < 37 cmH2O, only Pdet was statistically different (P=0.002).

After anti-incontinence surgery 76.1% of the patients who had SUI combined with DU could have improved incontinence without (54.9%) or with CIC (21.1%). In the SCI/ stroke subgroup, an improved outcome could still ieved with or without CIC, indicating this group patientshad more severe grade of DU. In the pelvic radiotherapy / radical hysterectomy subgroup, most patients had improved incontinence without CIC. In the other paients, up to 65.7% had improved incontinence without CIC. For the analysis of predictive factors, we found both Pdet and Pabd did not directly have effect on the three types of outcome. But for patients with Pdet ≥ 15 cmH2O, there were significant differences when we separated the outcome into improved incontinence without CIC or not, and separated the outcome into absence/improved incontinence with CIC or not. In terms of UDI-6 and IIQ-7, we found all scores decreased between pre-operation, 6 months and 12 months post-operatively, suggesting these patients were satisfied with treatment outcome although some of them need CIC after anti-incontinence surgery.

In women with SUI and DU, suburethral sling procedure is effective in improving the condition of SUI and quality of life. Pdet and Pabd are the only statistically significant predictive factors of surgical outcome. A lower Pdet favored the outcome of improved incontinence with CIC, while a higher Pabd tends to present the outcome of the use of CIC.