Improved early and late continence following robot‐assisted radical prostatectomy with concurrent bladder neck fascial sling (RoboSling)

Abstract Objective To describe a novel RoboSling technique performed at the time of robot‐assisted radical prostatectomy (RARP) and its utility for enhancing urinary function recovery postoperatively. Materials and Methods The surgical technique involves harvesting a vascularised, fascial flap from the peritoneum on the posterior aspect of the bladder. Following completion of prostatectomy, the autologous flap is tunnelled underneath the bladder and incorporated into the rectourethralis and vertical longitudinal detrusor fibres at the posterior bladder neck with a modified Rocco suture. After urethra‐vesical anastomosis is completed, the corners of the flap are hitched up to Cooper's ligament bilaterally with V‐Loc sutures, tensioned and secured creating a bladder neck sling. A prospective, longitudinal cohort study was performed of 193 consecutive patients undergoing RARP between December 2016 and September 2019. The first 163 patients underwent standard RARP, and the last 30 patients had the RoboSling technique performed concurrently. Continence outcomes were the primary outcomes assessed using pad number and Expanded Prostate Cancer Composite (EPIC)‐urinary domain questionnaire. Operative time (OT), estimated blood loss (EBL), complications and oncological outcomes were secondary outcomes. Results The two groups were comparable for demographics and clinicopathological variables. At 3 months, zero pad usage (p = 0.005) and continence rates, defined as EPIC score ≥ 85 (p = 0.007), were both higher in the RoboSling group. EBL, complication rate and positive surgical margin rate did not differ between the two groups. Superior zero pad usage was observed at 1 year in the RoboSling group (p = 0.029). The RoboSling technique added on average 16 min to OT. Conclusions The RoboSling procedure at the time of RARP was associated with earlier return to continence without negatively impacting other postoperative outcomes. This improvement in continence outcomes was maintained long term.


Conclusions:
The RoboSling procedure at the time of RARP was associated with earlier return to continence without negatively impacting other postoperative outcomes.
This improvement in continence outcomes was maintained long term.

K E Y W O R D S
incontinence, intraoperative sling, prostate cancer, prostatectomy, robotic surgery

| INTRODUCTION
Radical prostatectomy offers excellent localised prostate cancer control and long-term survival rates. Despite this success, the morbidity of prostatectomy has meant that urinary incontinence can be a major issue of prostate cancer survivorship. 1,2 Recovery of continence at 12 months following radical prostatectomy ranges from 60% to 93%, depending on the criteria used. [2][3][4] Early continence rates are substantially lower than this, varying between 28% and 74%, 4,5 and can have a deleterious effect on quality of life (QoL) for these patients. 6 Robotic-assisted radical prostatectomy (RARP) demonstrates similar oncologic outcomes as open radical prostatectomy (ORP) or laparoscopic radical prostatectomy (LRP). 7,8 There is evidence of improved 12-month urinary continence rates for RARP compared with ORP or LRP, although the overall quality of studies was poor. 9 Furthermore, there was no consensus on the definition of continence with some studies using zero pad usage to define continence and others allowing the use of a safety pad for patients still considered continent. 9 The only Level 1 evidence comparing functional outcomes between RARP and ORP did not demonstrate any difference in urinary continence either in the short-term or in 24 months between the two groups. 10  A number of novel reconstructive and prophylactic surgical techniques have been described in the literature to improve continence. 12,13 Concurrent intraoperative placement of slings during RARP is one such concept. [14][15][16][17] Despite promising cohort data and a previous ORP trial demonstrating prophylactic sling benefit, recent randomised RARP trials have demonstrated no early continence benefit for non-vascularised slings. 16,17 To our knowledge, there are no surgical techniques yet demonstrated during RARP that have used a vascularised, autologous sling, which supports the bladder neck and vesicourethral anastomosis.
The objective of this study was to detail our technique and to assess its efficacy on enhancing urinary continence after robotic prostatectomy.

| Primary outcomes
Primary outcomes of pad usage were evaluated at 3 and 12 months postoperatively. Pad usage at each time point was measured as average pad use per day for the preceding week. Patients filled in the Expanded Prostate Cancer Composite (EPIC)-urinary domain questionnaire 18 at 3 and 12 months postoperatively. This is a validated self-assessment questionnaire composed of 12 questions that address continence, as well as other voiding problems. The EPIC score ranges from 0 to 100 points with higher scores signifying better quality urination; however, it lacks a clear definition differentiating continence from incontinence. Previous studies have indicated that an EPIC score ≥85 is associated with men being satisfied with their urinary continence, and therefore, in our study, a cut-off score of 85 is used to compare outcomes. 19

| Statistical analysis
Baseline variables were compared between groups. Categorical variables were compared using the chi-squared test (frequencies and proportions). Continuous variables were compared using the t-test (means) or Wilcoxon 2-sample test (median). All statistical analyses were performed using SPSS version 25 (SPSS Inc., Chicago, IL, USA).

| RESULTS
The study consisted of 30 patients who underwent RARP with concurrent RoboSling and 163 without the RoboSling. Baseline characteristics did not differ between the two groups (Table 1). A total of 151 patients (78% response rate) filled in their 3-month postoperative questionnaire, and 141 patients (73% response rate) filled in their 12-month questionnaire. The continence outcomes for the study population are outlined in Table 2. At 3 months, zero pad usage in the RoboSling group was significantly higher (44% vs. 16.5%, p = 0.005).
The RoboSling group's EPIC score was higher at 3 months (mean 62 vs. 43, p = 0.008). The percentage of EPIC score ≥85 at 3 months was higher with RoboSling placement (28% vs. 7%, p = 0.007), which is further evidence of better early continence.
With longer follow-up, the continence outcomes of the two groups improved as expected ( Figure 5). At 12 months, the mean EPIC scores were not significantly different between the two groups (73 vs. 65, p = 0.237). The number of patients with EPIC ≥85 was also similar between the two groups at 1 year. Despite no real difference in EPIC score, men wearing zero pads at 12 months in the RoboSling group were significantly higher (72.2% vs. 44.7%, p = 0.029).
There were no significant differences demonstrated for EBL, LOS or pathological outcomes, including no difference in the PSM rate (   Table S2).  There are several limitations that should be noted for this study.

| DISCUSSION
Confounders such as prostate volume to pelvic volume ratio, preoperative urethral length and angle and bladder neck size may affect continence outcomes and were not assessed in this cohort of patients.
Second, while questionnaires were provided prospectively, patients were completing these with retrospective recall of the preceding period, with potential for associated bias. Third, in our study, the rates of continence, particularly in the control group, are lower than other rates published in the literature 18 ; however, it should be noted that a strict definition of 'zero pads' was used to define continence, and furthermore, as a public teaching hospital, these cases were predominantly performed with the trainee or fellow as the primary surgeon on the console. Additionally, there continues to be no clear consensus on a measurable definition of continence, and the use of 'pad number' as a measure of the degree of incontinence may not be reliable. For example, an incontinent patient who loses urine but refuses to wear pads could hardly be considered continent. Conversely, a careful man who hardly leaks but changes his pads multiple times daily to maintain hygiene may be misinterpreted to be reliant on pads when he is actually not. Therefore, a more accurate measure of incontinence is 24-hour pad weight as it better quantifies the amount of leakage.
24-hour pad weight in combination with QoL measures (EPIC, SF-36) would be the optimal tools for any future studies to quantify urinary incontinence outcomes following prostate surgery. 23 Finally, as this was a non-blinded study, there is potential for bias as patients' knowledge they are receiving a RoboSling could influence their symptom scores and contribute to them wearing less pads. These limitations are addressed in the blinded, RCT that is currently underway at our institution.

| CONCLUSION
In summary, the RoboSling technique is a novel, easily performed intraoperative sling at the time of RARP that demonstrates improved rates of continence both in the short term and in 1-year following surgery without a higher complication or positive surgical margin rate.
A randomised controlled study is now enrolling at our institution to further assess the benefits of this technique.