Artificial urinary sphincter (AUS) is a therapeutic option in female patients with stress urinary incontinence (SUI) due to intrinsic sphincter deficiency (ISD). Female AUS is gaining popularity in several countries with the rise of robotic implantation which improves greatly the perioperative outcomes. The AMS-800 AUS is a silicone device made of three pieces: a cuff which is placed around the bladder neck, a pressure regulating balloon (PRB) which is placed in the Retzius space and a pump which is placed in the labia majora. The patient has to squeeze the pump to deflate the AUS cuff which result in opening of the bladder neck allowing the patient to void with low urethral resistance. While pump manipulation is rarely an issue in male AUS patients, this may be different in female patients due to anatomical or cultural reasons.  The aim of the present study was to assess the prevalence of difficulties to manipulate the pump in female AUS patients as well as the risk factors and management of this challenging situation.

Study design
The data of all female patients who underwent a robotic AUS implantation at a single academic center between January 2014 and May 2023 were collected prospectively. All cases were numbered in chronological order which was defined as the overall center’s experience with robotic female AUS implantation.

AUS implantation and activation 
The AUS was activated at six weeks during a 6 to 10 hours hospitalization. The patients were taught how to manipulate the pump and had to perform multiple voids under close supervision of a specialized nurse. Post void residual (PVR) was checked after each micturition. The patient was discharged with an activated AUS only if PVR were < 100 ml and the manipulation of the pump was deemed satisfactory by the specialized nurse and the surgeon. 

Outcomes of interest
The primary endpoint of the present study was temporary difficulties defined as the need for at least one other short hospitalization to learn pump manipulation. The secondary outcomes were i) initial difficulties to manipulate the pump defined as any mention in the patients’ charts of difficulties to perform pump manipulation during the initial activation hospitalization ii) Permanent difficulties defined as the need to permanently deactivate the device due to impossibility to manipulate the pump that could not be overcome despite several hospitalization iii) complications arisen directly from difficulties to manipulate the pump iv) serious difficulties defined as permanent deactivation and/or surgical revision to reposition the pump and/or complications arisen from difficulties to manipulate the pump.

Statistical analysis
Means and standard deviations were reported for continuous variables, medians and ranges for categorical variables and proportions for nominal variables. Comparisons between groups were performed using the χ2 test or Fisher's exact test for discrete variables, and Mann-Whitney test for continuous variables as appropriate. Statistical analyses were performed using JMP v.12.0 software (SAS Institute Inc., Cary, NC, USA). All tests were two-sided with p <0.05 as a threshold to define statistical significance.

Patients’ characteristics
Out of 88 female AUS patients included, 20 had initial difficulties to manipulate the pump (22.7%) 16 had temporary difficulties to manipulate the pump requiring at least one rehospitalization (18.2%) and four had permanent difficulties resulting in permanent deactivation (4.5%). 

Difficulties to manipulate the pump
Surgical reoperations were required to reposition the pump in four patients (4.5%) which resulted in successful pump manipulation in only two patients. Five patients experienced complications from their difficulties to manipulate the pump (5.7%) all of which were acute urinary retention (AUR). One of this AUR resulted in a severe urinary tract infection with septic shock and admission in intensive care unit. There were six serious difficulties in total (6.8%). The median number of additional hospitalizations to learn proper manipulation was 1 (range: 1-3). In patients with temporary difficulties, the median time to successful manipulation was 3 months (range: 2-5). 

Predictive factors
The two only variables significantly associated with temporary difficulties were longer operative time (183.4 vs 159.1 min; p=0.04; see table 1) and overall center’s experience (32 vs. 50; p=0.04). The median age was higher in the temporary difficulties group (70 vs 65 years) and so was the BMI (29 vs. 27.7 kg/m2) but these differences were not statistically significant (p=0.08 and p=0.19 respectively). The only variable significantly associated with serious difficulties to manipulate the pump was the overall center’s experience (11 vs. 47; p=0.004; see table 2)

The present study is the first aiming to assess the prevalence of difficulties manipulating the pump and describe its consequences and management. We found that difficulties were more prevalent than expected, that they could be solved in most instances but that they required surgical revisions and permanent deactivation in some cases. 

In light of the present findings, we believe that pump manipulation in female AUS patients would deserve careful attention from clinicians and researchers in the field. Further studies would be needed to better elucidate the determinants of difficulties to manipulate the pump. Several mechanisms could be assumed to play a role in difficulties to manipulate the pump: cognitive dysfunction, manual dexterity, difficulties to access the labia; device dysfunction (air in the system); local problems (pump malposition/hematoma)

Another important finding of the present study is that, although most difficulties to manipulate the pump are solved once they diagnosed, some of these difficulties may lead to serious problems. We believe this finding entails standardized patients’ education program and dedicated follow-up protocol to prevent and manage these challenging and potentially harmful situations

Operative time may be a surrogate for case complexity but most likely largely reflects the impact of the learning curve. Hence the stronger determinant of difficulties to manipulate the pump is probably the learning curve per se which may affect patient’s selection, pump positioning and patients’ education to properly manipulate the pump.

We suggest hypothesis that may overcome difficulties to manipulate the pump such has electromechanical devices, abdominal pump and proper patients’ education and training

The present study has several limitations that should be acknowledged. First it is a retrospective analysis of a prospective database with numerous inherent biases. Especially, we lacked validated tools to assess manual dexterity, cognitive function and access to the labia majora preoperatively.
It's a single center study with no relatively small sample. There is no universally accepted definition of difficulties to manipulate the pump.

Difficulties to manipulate the pump are relatively common in female AUS patients. Most of these difficulties resolve with repeat patients’ education and careful follow-up but they may result in surgical revision, multiple hospitalizations and serious complications such as septic shock. Proper patients’ education, careful monitoring at the time of activation and awareness of this issue in the medical community may help to minimize the consequences of these difficulties. Developing and validating tools to identify preoperatively patients at risk of difficulties manipulating the pump may help in treatment decision making in the context of the upcoming electromechanical AUS.

Continence 12S (2024) 101476
DOI: 10.1016/j.cont.2024.101476