In the last years, the role of urodynamic investigations in the preoperative evaluation of female stress urinary incontinence (SUI) has been questioned (VALUE Trial)(1). Several authors state that the execution of invasive urodynamic investigations does not change the surgical outcomes or the following therapeutic decisions in patients with uncomplicated SUI. On the other hand, some urodynamic parameters have been correlated with poorer surgical outcomes (2). The aim of this study is to assess the impact of preoperative patient’s use of abdominal straining on postoperative outcomes in women treated with surgery for uncomplicated SUI.

Data from consecutive female patients who underwent suburethral tape - obturator approach (TVT-O) surgery for SUI in one center were prospectively collected and retrospectively analyzed. Patients were categorized as presenting with uncomplicated stress urinary incontinence according to the definitions used in the VALUE trial. Briefly, inclusion criteria were: history of pure SUI without voiding dysfunction, detrusor overactivity and OAB. Exclusion criteria included previous UI surgery, pelvic radiation, pelvic surgery within the last 3 months, and anterior or apical pelvic organ prolapse (POP) ≥ +1 cm. All patients underwent an office evaluation including history and physical examination and a urodynamic investigation comprising uroflowmetry with postvoid residual volume (PVR) evaluation, cystometry and pressure/flow study. Patients were divided in two groups, according to the presence or absence of use of abdominal straining during voiding (present in group A, absent in group B).
At five year follow up, patients were investigated for presence of voiding dysfunction (VD, defined through lower urinary tract symptoms of the voiding phase and urodynamics signs: PVR > 100 ml and Qmax < 15 ml/s) and de novo overactive bladder syndrome (OAB). Post-TVT-O urinary retention (UR) was defined as the need of intermittent or at least 24h permanent catheterization with or without a sling revision.

One hundred and ninety-two female patients underwent TVT-O surgery for uncomplicated SUI. Preoperative abdominal straining was identified in 60/192 patients (Group A: 31.2% of the patients). Qmax was not different in the two groups (Group A: 19,5 vs. Group B: 20,5 ml/s, p=0,76). Demographics was similar for the two groups regarding age, parity, BMI (p>0,05). At a 5 year follow up, UR cases were not statistically significant (Group A: 4 vs. Group B: 2, p=0,08). VD was reported in 9/60 (15%) patients in Group A and 8/132 (6%) patients in Group B (p=0,056), OAB was reported in 23/60 (38,3%) patients in Group A and 26/132 (19,7%) patients in Group B (p=0,007).

Preoperative use of abdominal straining was found to be related to a significant higher incidence of de novo OAB. In particular, OAB was present in 38,2% of patients using vs. 19,7% of patients not using abdominal straining. The risk of developing OAB after TOT surgery seems to be almost two-fold higher among female patients with uncomplicated SUI using abdominal straining. Although a significant correlation was not found, a trend for a higher incidence of postoperative voiding dysfunction was also observed in preoperative abdominal straining patients (15% vs 6% in the non-straining patients, p=0,056).

The use of abdominal straining seems related to the risk of developing OAB. A trend for a higher percentage of patients with VD among patients using the abdominal straining during voiding was also found. Further and best powered studies are needed to better define the impact of preoperative abdominal straining on OAB and voiding dysfunctions in women who undergo SUI surgery. Nevertheless, the role of invasive urodynamics seems relevant in providing more informations to surgeons and to patients on the probability for female subjects with uncomplicated SUI to develop de novo OAB.

Nager CW, Brubaker L, Litman HJ, Zyczynski HM, et al. A Randomized Trial of Urodynamic Testing before Stress-Incontinence Surgery. N Engl J Med 2012; 366:1987-1997
Giarenis I, Cardozo L. What is the value of urodynamic studies before stress incontinence surgery? BJOG 2013;120:130–132