To propose a new way to objectively evaluate the external sphincter function prior to male sling surgery.

Study Group
	Between April 2016 and April 2017 ten consecutive patients with median age 68.5 (54-79) and duration on incontinence 88.3+ 71.4 months had comprehensive incontinence workup done for stress urinary incontinence (SUI). Etiology of incontinence was retropubic radical prostatectomy (RRP) in 4 (40%), transurethral resection of the prostate (TURP) in 4 (40%) and RRP associated with salvage radiation therapy in 2(20%). The incontinent assessment included the International Consultation on Incontinence Questionnaire – Short Form (ICIQ-SF), 24-hour pad test, urodynamics, urethroscopy and RT. Urodynamics was performed according to the International Continence Society (ICS) recommendations.7 During urodynamics the urethral pressure profilometry (UPP) was performed to evaluate sphincter function. Measurements of SPAR and SPUC were recorded (detailed description below). RT was performed during cystoscopy to evaluate urethral mobility and sphincter function as described by Rehder P.8,9 All patients underwent a RTS surgery and the same assessment were repeated in the postoperative (except urodynamics). Postoperatively patients were divided in two groups: continent or incontinent. Definition of continence was no pad usage.
	The time elapsed between prostate and sling surgery was greater than 26 months. The surgeries were performed by two experienced urologists according to the technique described by Redher and Gozzi.10 A polyvinylidene fluoride (PVDF) sling was used, which is a highly non-reactive thermoplastic fluoropolymer produced by the polymerization of vinylidene difluoride, Dynamesh-PR™. Exclusion criteria included the presence of anastomotic or urethral strictures on cystoscopy, high glucose blood levels (glycosylated hemoglobin higher than 7.5%), and previously failed treatments for incontinence. Informed consent was obtained from all patients and ethical institutional review board approved the study.

Sphincter pressure at rest and under contraction (SPAR and SPUC)
	The SPAR and SPUC evaluation was done according to the Brown-Wickham water perfusion method of urethral profilometry profile with a 10F catheter with four holes around the circumference, 5cm distal of the tip.5 Transducers were zeroed to atmospheric pressure at the pubic symphysis level. The catheter was introduced into the bladder. The bladder was filled with 150 ml of normal saline solution at room temperature, and with the patient in the lying position the urethral catheter was manually withdrawn. The perfusion rate was 2 mL/min. The infusion and transducer lines were connected to the bladder catheter through a three-way tap to register initial bladder pressure. The catheter was withdrawn at 1mm/s traction down the urethra and the pressure profile was recorded. The point of high pressure was considered the external sphincter localization. At this point the pressure was recorded as the SPAR. Then patients were asked to perform a pelvic floor contraction maneuver and the SPUC was recorded. This maneuver was repeated five times, with a three minutes interval and the medium value of the three highest SPUC was obtained for statistical analyses. Finally, the catheter was withdrawn until the holes around the circumference were clear of the external meatus (Fig. 1)

Median follow-up was 12 months (6-19). There were no major complications regarding sling implant. According to the aforementioned continence criteria the results were analyzed in two groups according to the postoperative 24h-pad test (primary endpoint). On this way 4 of 10 (40%) composed the continent group and 6 of 10 (60%) the incontinent one. The ICIQ-SF score in the preoperative in the continent and incontinent group was respectively 17.7+1.2 and 18.3+2.3 (p = 0.51). In the preoperative this score in continent and incontinent group turned respectively to zero and 14.6+2.42 (p = 0.01). There was also no significant difference in preoperative urodynamic parameters between continent and incontinent groups. The main results of this study are resume in table1. Pre-operatively 24-hour pad test in the continent group was 151+84.2gm (median 140, range 80 to 245) and in the incontinent group was 973+337.1gm (median 1940, range 550 to 1200) (p = 0.008). Mean SPAR in the continent and incontinent group was respectively 65.2+22.5 cmH20 (median 62.8, range 40.6 to 94.6) and 39.5+12.9 (median 41.1, range 23 to 58) (p = 0.03). Mean SPUC in the continent and incontinent group was, respectively 188+8.8 cmH20 (median 185.1, range 181 to 201) and 96.9+49.4 cmH20 (median 109.9, range 35.6 to 163.6) (p = 0.008). In all continent patients SPUC was higher than 180 cmH20. The RT was positive in 3/4 continent patients and 3/6 in of the incontinence patients (false positive). The SPUC in false positive RT patients were 163.6, 120, and 100.6 cmH20 respectively. RT was negative in on continent patient (false positive) and in 3/6 incontinent patients. All patients with low weight pad test (under 245gm) presented with high pressure SPUC (over 180cmH20) and achieved complete continence.  In the two patients with very low SPUC (patients #6 and #8) the repositioning test was negative and the pad test had high weight. Even in patients that did not achieve complete cures (SPUC < 180cmH20) there was a positive correlation between SPUC and postoperative pad test values. In the patient with the SPUC 163.6cmH2O the pad test reduction was better compared to patients with SPUC 120cmH2O or lesser (85% vs. 42-52% reduction).

To the best of our knowledge, there is no report using the SPAR and SPUC to predict success in RTS surgery. In our opinion RT is extremely observer dependent. The correct classification of positive or negative test is completely visual and may vary between observers. On this way the RT is a subjective and non-numeric test. It is also hard to compare RT results and consequently preoperative characteristics between different cohorts. This test seems to be very useful in the selection but its subjectivity may be a barrier to a widely usage. In our cohort false positive rates in RT were found in 30% of the patients, which may be a possible explanation to failure rates on “ideal“ candidates to RTS. The RT was positive in three patients that did not achieve complete continence. In these three patients, SPUC were respectively 163.6, 120 and 100.6 cmH2O demonstrating that they presented contraction but not enough to get continence after sling implantation.  In our study, all patients that presented with SPUC values higher than 180cmH2O had low weight pad test (under 245gm) demonstrating good correlation between the two methods.  On this preliminary report, the SPAR and SPUC (especially SPUC) presented good association with sling surgery success.

This is a preliminary report proposing the use of SPUC as objective evaluation of the external sphincter function prior male sling surgery. SPUC needs to be reproduced in larger cohorts to be validated and standardized but seems to be a way for optimizing the sphincter evaluation as well to become a useful tool for patient selection to RTS surgery.

Rehder P, Gozzi C: Transobturator sling suspension for male urinary incontinence including post-radical prostatectomy. Eur Urol 2007; 52:860-6
Lentz AC, Peterson AC, Webster GD: Outcomes following artificial sphincter implantation after prior unsuccessful male sling. J Urol 2012; 187:2149-53
Bauer RM, Gozzi C, Roosen A, et al: Impact of the 'repositioning test' on postoperative outcome of retroluminar transobturator male sling implantation. Urol Int 2013; 90:334-8