Is detrusor underactivity associated with voiding dysfunction after single incision sling surgery?

BACKGROUND: Some women experience voiding dysfunction after stress urinary incontinence (SUI) surgery. We explore if detrusor underactivity (DU) found in urodynamic study (UDS) prior to SUI surgery using an adjustable single incision sling (SIS) may be related to voiding dysfunction after surgery. METHODS: This is a prospective, diagnostic, transversal, single center study comparing voiding dysfunction after SUI surgery with a SIS (Altis®; Coloplast, Humlebæk, Denmark) between women with DU (cases) or normal detrusor (controls). Inclusion criterium was women ≥18 years with SUI/mixed UI (stress predominant) operated between June 2013 and December 2020. Exclusion criteria were: women without UDS prior to surgery or without voiding phase in the P/Q, previous incontinence surgery, POP stage ≥2, neurogenic conditions, other pelvic floor surgery. Urinary symptoms were assessed using structured questions evaluating storage/voiding symptoms. Patients were divided into two groups according to projected Isovolumetric Pressure Index (PIP1) with 30-75 cmH2O indicating normal contractility. RESULTS: A total of 139 women were included, 29 (20.9%) in DU group and 110 (79.1%) in control group. Control and DU groups have shown similar objective (75.5% vs. 71.4% P=0.66) and subjective (85.4% vs. 96.1% P=0.22) success rates, respectively, without statistical differences. Voiding symptoms increased after surgery in both groups (+20.7% DU group vs. +8.1% normal group, P=0.29). More voiding symptoms (persistent/de novo) were found in DU group vs. normal group, but without statistically significant differences. CONCLUSIONS: According to our results, the presence of DU previous to SUI surgery with a SIS (Altis®, Coloplast) has no impact on objective and subjective success rates. On the other hand, patients with preoperative DU showed higher proportion of voiding dysfunction but no statistical difference.