Male sling placement has been proved to be an effective treatment for postprostatectomy urinary incontinence (PPI). The existence of a learning curve (LC) has been established for sling surgery in females [1]. Male sling implantation has several critical steps and may potentially involve a LC. Scant and conflicting data are available on this topic that may have implications concerning training and evaluation of surgeons. We aimed to perform a LC analysis of a single surgeon’s experience of sling placement evaluating multiple outcomes.

From Jan. 2013 to Dec. 2018, consecutive patients with PPI undergoing sling placement at our institution were included. Only patients that underwent implantation of the same sling (TiLOOP Male) were included. Exclusion criteria included previous sling, incontinence due to causes different from radical prostatectomy, and follow-up lower than 12 months. 
TiLOOP Male, a 2-arm titanium-coated fixed retrourethral sling, was implanted using an inside-out, single-incision standard technique, leaving the bulbourethral muscle in place and attaining the cranial relocation of the proximal bulbar urethra [2].
LCs were derived by the cumulative sum (CUSUM) control chart analysis using the cumulative observed minus expected failure method [3]. Expected values were obtained from published literature. 
The primary outcome was the 12-months failure of objective cure (no pad use or 1 dry “security” pad). Secondary outcomes included 12-months failure of overall objective success defined as cure plus improvement (reduction of at least 50% of the pad count), 12-months failure of subjective success evaluated with PGI-I, operative time>60 minutes, need for further incontinence surgery (performed or scheduled) and overall complications occurrence. To adjust for case-mix, multivariate logistic regressions were performed using surgical order, adjusted for age, BMI, incontinence severity, pelvic irradiation, and previous urethrotomy, to predict outcomes.

Sixty-five patients (mean age 68 ±5.8 years) with a mean follow-up of 46.2 ±20.5 months were included. CUSUM analyses revealed clear LC effects for continence outcomes, operative time and need for further incontinence surgery, but not for complications occurrence. LC effect was graphically more evident for objective cure than for overall objective success, with a plateau achieved after 59 cases (Figure 1).
At multivariate analyses, surgical order (OR=0.96; CI:0.93-0.99;p=0.031) and irradiation (OR=10.7; 95%CI:1.18-97.1; p=0.035) were statistically significant for predicting 12-months failure of objective cure, while irradiation was the sole variable independently predicting 12-months failure of overall objective success (OR=27.4; 95%CI: 4.8-156.3;p=0.000). Surgical order and irradiation were also independent predictors of 12-months failure of subjective success and of need for further incontinence surgery.

A rather long learning curve was observed in our series of sling placement to achieve stable proficiency, especially when objective cure was considered as continence outcome, independently from main factors involved in patient selection.

Individualized structured training with expert mentorship for urologists naïve in male sling surgery should likely benefit patients treated in the initial surgeon’s experience. This study supports the CUSUM analysis as an effective method for surgeons’ self-appraisal to prompt continuous quality improvement.

Hilton P, Rose K. The “learning curve” for retropubic mid-urethral sling procedures: a retrospective cohort study. Int Urogynecol J. 2016 Apr;27(4):565-70
Sacco E, Gandi C, Vaccarella L, et al. Titanized Transobturator Sling Placement for Male Stress Urinary Incontinence Using an Inside-out Single-incision Technique: Minimum 12-Months Follow-up Study. Urology. 2018;115:144-150
Biau DJ, Resche-Rigon M, Godiris-Petit G, Nizard RS, Porcher R. Quality control of surgical and interventional procedures: a review of the CUSUM. Qual Saf Health Care. 2007 Jun;16(3):203-7