Midterm postoperative results of mid-urethral slings. Role of ultrasound in explaining surgical failures

Surgical treatment for stress urinary incontinence (SUI) with mid-urethral sling (MUS) is considered to have a high success rate. However, between 5% and 20% of MUS fail, with inadequate surgical implantation being a possible cause of SUI persistence or recurrence. Misplacement of a MUS can be determined by pelvic floor ultrasound (PF-US). The aim of this study was to investigate the role of PF-US in patients with persistent or recurrent urinary incontinence (UI) symptoms after MUS surgery for SUI with a midterm follow-up.

A historical cohort study including women undergoing MUS surgery for SUI between 2013 and 2015 was designed. The primary outcome was to correlate the sonographic parameters of MUS with SUI cure (negative International Continence Society-Uniform Cough Stress Test, Incontinence Questionnaire-Short Form < 5 points and no symptoms of SUI), at 5 years postsurgery. Secondary outcomes were changes of maximum urethral closure pressure (MUCP) and symptoms of urgency urinary incontinence (UUI) at 1 and 5 years after surgery.

Eighty-seven patients (80 transobturator-MUS, 7 retropubic-MUS) were included. At 5 years all patients referred improvement of UI and objective cure of SUI was demonstrated in 81.2%. The MUS was sonographically correct in 67 (98.5%) of the 68 patients with cure of SUI. The MUS was considered incorrectly placed in only 4 (28.6%) of the 14 patients with noncured SUI. MUCP decreased from 61.9 to 48.8 cmH₂ O at 5 years of follow-up (p < 0.01) and up to 53% of women had UUI symptoms after surgery, with a nonsignificant decrease compared to baseline.

Patients cured of SUI had sonographically correct MUS by PF-US. Less than one-third of cases of SUI persistence or recurrence after MUS surgery could be explained by a sonographically incorrect sling. Low urethral resistance and/or UUI symptoms could help to explain the remaining failures. Complete functional and anatomic studies, including urodynamics and PF-US, should be performed before deciding on the next management strategy in patients with SUI persistence or recurrence after MUS.