Hypothesis / aims of study
Although stress urinary incontinence (SUI) is a very common condition, its pathophysiology has not been clearly elucidated. Therefore, the cases of failure after anti-incontinence procedures are difficult to explained. Interestingly, the point of insertion of the sub-urethral slings has evolved through time: from 0.5 cm from the external urethral orifice (EUO), to 1 cm from the EUO, to the ‘1/3 rule’ from the EUO, and currently to the half of the length of the urethra, although there are authors suggesting even more proximal to the internal urethral orifice (IUO) insertion of the sling [1].
Urethral motion profile (UMP) is a sonographic modality that assists in the assessment of urethral mobility. The urethra is divided into six equidistant points from the bladder neck to the EUO, and their mobility is calculated with measurements at rest and at maximum Valsalva maneuver. Increased UMP appears to be associated with SUI [2].
The evaluation of the placement of the sling in relation to the UMP and the distances from the EUO and the IUO is a concept that has not been studied in depth. The aim of this study was to pre-operatively calculate the UMP in SUI patients, and then investigate the relationship of the tape position post-operatively with the successful outcome.
Study design, materials and methods
Data from a prospective cohort study that was conducted from December 2019 to January 2023 were obtained. Consecutive patients treated with SIMS for SUI were included. The patients presented with SUI, and they were initially examined in the outpatient department [history, POP-Q, cough stress test, urodynamic exam, and pelvic floor ultrasound (PFUS) including UMP]. Patients with elvic organ prolapse and previous incontinence surgery were excluded. The patients were evaluated 3-6 months post-operatively with a clinical examination that included stress test, PFUS including evaluation of the tape position and the tape mobility, and incontinence questionnaires (PGI-I, PGI-S, ICIQ-SF). Statistical analysis was performed with Microsoft EXCEL.
Interpretation of results
Failed slings were associated with higher Qmax and lower UMP. This is in accordance with the generally accepted notion that slings increased success rates in women with well mobile urethra compared to women with limited mobility urethras. Ultrasound has the advantages of a non-invasive method that can be studied with high technology instruments in order to provide in-depth analysis.