Abstract
Introduction:
Few studies have examined the patient characteristics that lead to early continence after robot-assisted radical prostatectomy (RARP), and to date, there has been no investigation into the predictors of immediate continence. In the current study, we examine a large multisurgeon population of patients undergoing RARP to assess for predictors of this outcome.
Patients and Methods:
Between January 2008 and December 2010, 1270 patients who underwent RARP at our institution, with complete preoperative and follow-up data, were assessed for urinary function prospectively. Univariable and multivariable logistic regressions were used to assess for predictors of zero pad usage after RARP. Patient and operative characteristics examined include age, body–mass index, prostate-specific antigen, adjusted Charlson comorbidity index (CCI), Gleason sum, international prostate symptom score, clinical stage, nerve sparing, bladder neck reconstruction, posterior anastomotic reconstruction, surgeon volume, and percutaneous suprapubic tube (PST) bladder drainage.
Results:
Overall, 17.3% of patients (n=219) never required a pad after catheter removal. Characteristics associated with never requiring a pad are age, preoperative Gleason sum, CCI, nerve sparing, prostate weight, surgeon volume, and PST bladder drainage. Independent predictors of never requiring a pad after catheter removal included nerve-sparing (B/L standard as referent) wide dissection [OR: 0.96 (95% CI: 0.49, 1.88)], unilateral inter-/intrafascial [OR: 1.20 (0.70, 2.06)], bilateral inter-/intrafascial [OR: 1.97 (1.36, 2.86)], and PST drainage [OR: 2.53 (1.56, 4.11)].
Conclusion:
In a study reflective of broad RARP practice at our institution, 17.3% of patients were entirely pad free after RARP. The type of nerve sparing performed and placement of a PST for bladder drainage postoperatively were found to be independently predictive of never requiring a pad after RARP.
Introduction
Few studies have examined the patient or perioperative characteristics that lead to early continence, and to date, there has been no investigation into the predictors of immediate continence after RARP. A single contemporary study has examined predictors of early 3-month continence rates after RARP, but it is limited by its single-surgeon population. 3 In the current study, we examine a large multisurgeon population of patients undergoing RARP to assess for predictors of immediate early continence without pad usage.
Patients and Methods
Study population
Between January 2008 and December 2010, 1649 patients underwent RARP at our institution by one of five surgeons using the technique of Menon et al. 4 with modifications in 2007 and 2009. 5,6 Three-hundred eighty patients had incomplete data or refused to participate in our follow-up protocol, leaving 1269 in the study cohort. All cases were performed with the 3-arm Da Vinci system (Intuitive Surgical, Sunnyvale, CA) using an anterior intraperitoneal approach with early exposure of the prostatovesical junction. Nerve sparing was performed in patients who were potent (SHIM >17) unless otherwise indicated for oncological control. Pelvic lymphadenectomy (PLND) was performed by all surgeons for moderate and high D'Amico risk patients; however intersurgeon variability existed on nodal dissection for low-risk disease. Patients with low-to-intermediate risk disease had PLND limited to the internal iliac and obturator zones, whereas extended PLND was performed for patients with palpable T2b-T3 disease, Gleason score of 8–10, or prostate-specific antigen (PSA) >10 ng/mL.
Anastomosis technique varied according to surgeon preference. The majority of cases (n=1016) were performed according to a multilayer anastomotic approach previously described. 7,8 One surgeon (H.S.) performed single-layer anastomotic closure. 9 All anastomoses were performed with monofilament poliglecaparone (Monocryl; Ethicon, Sommerville, NJ) before January 2010; subsequently, all anastomoses were performed with barbed 3-0 polyglyconate suture (V-Loc®; Covidien, Mansfield, MA). The integrity of the urethrovesical anastomosis was confirmed intraoperatively with intravesical instillation of 250 mL of sterile saline, and if any leakage was observed, additional interrupted sutures were placed to ensure a watertight anastomosis.
Percutaneous suprapubic tube (PST) drainage was the preferential method of bladder drainage for three of five surgeons when clinically indicated and was performed as previously described. 8,10 Transurethral catheterization was used intraoperatively to aid in the creation of the urethrovesical anastomosis, and the urethral catheter was removed at the end of the case. Cystograms were obtained routinely by all surgeons until July 2008, and subsequently only when clinically indicated, or at the discretion of the operating surgeon.
Follow-up
Demographic and follow-up data were collected prospectively and entered into an IRB-approved patient database; additional information was ascertained from institutional electronic medical records, hospital billing records, outpatient medical records, and communication with patients and referring physicians. Functional outcomes were assessed prospectively by patient-administered questionnaire at 3, 6, 9 12, 18, and 24 months postoperatively. Immediate continence was ascertained by the question, how many weeks to no pads per day, with an answer of 0. Database management was performed by individuals not involved in direct clinical care. The study protocol was approved by the Institutional Review Board of Henry Ford Hospital. Data collection and follow-up correspondence were done in accordance with the Health Insurance Portability and Accountability Act.
Description of covariates
Demographic and preoperative characteristics recorded included age, body–mass index (BMI), adjusted Charlson comorbidity index (CCI), 11 international prostate symptom score (IPSS) (grouped by lower urinary tract symptom severity), PSA, biopsy Gleason score, clinical stage (AJCC 2009 guidelines), and prostate weight. Operative characteristics included type of nerve sparing performed (wide dissection, bilateral standard, unilateral inter-/intrafascial, or bilateral inter-/intrafascial), requirement of a bladder neck reconstruction (BNR), anastomotic layers, PST bladder drainage placed at surgery, and estimated blood loss. Surgeon volume over the study period was included as a covariate.
Statistical analyses
Categorical distributions are reported as counts (%) and continuous variables as medians and interquartile range. Fisher's exact test and chi-square test were used to assess differences in distributions among categorical variables. The Mann–Whitney U (Wilcoxon rank-sum test) was used to assess the difference in distributions among continuous variables.
Univariable and multivariable logistic regression models were constructed to assess for predictors of immediate continence. Factors that were associated with immediate continence on univariable analysis were entered into the multivariable model. All tests were two-sided, with a statistical significance set at p<0.05. Analyses were conducted using the statistical package for R (the R foundation for Statistical Computing, version 2.12.2).
Results
Overall, 17.3% of patients (n=219) never required a pad after catheter removal following RARP (Table 1). Patients with immediate return of continence requiring no pad usage tended to be younger, healthier, with lower prostate weight and were more likely to have Gleason 3+3 disease (Table 1). They had more frequently undergone a bilateral nerve-sparing procedure, and subsequent PST bladder drainage (Table 1).
p-Values in bold are statistically significant.
BMI=body–mass index; BNR=bladder neck reconstruction; EBL=estimated blood loss; IPSS=international prostate symptom score; IQR=interquartile range; PSA=prostate-specific antigen; PST=percutaneous suprapubic tube.
Patient and operative characteristics that are associated on univariable analysis with never requiring a pad are age at surgery [OR: 0.96 (95% CI: 0.94, 0.97)]; preop Gleason sum (6 as referent) 3+4 [OR: 0.74 (95% CI: 0.54, 1.03)], 4+3 [OR: 0.55 (95% CI: 0.33, 0.90)], ≥8 [OR: 0.48 (95% CI: 0.27, 0.85)]; adjusted CCI (0/1 as referent) 2 [OR: 0.66 (95% CI: 0.48, 0.91)], ≥3 [OR: 0.36 (95% CI: 0.23, 0.56)]; nerve sparing (standard nerve sparing as referent) wide dissection [OR: 0.80 (95% CI: 0.43, 1.49)], unilateral inter-/intrafascial [OR: 1.52 (95% CI: 0.90, 2.56)], bilateral inter-/intrafascial [OR: 2.50 (95% CI: 1.80, 3.46)], prostate weight [OR: 0.99 (95% CI: 0.98, 1.00)], PST bladder drainage [OR: 3.12 (95% CI: 1.96, 4.94)], and increasing surgeon volume [OR: 1.00 (95% CI: 1.00, 1.00)] (Table 2).
p-Values in bold are statistically significant.
On multivariable analysis, independent predictors of never requiring a pad after catheter removal after RARP included nerve-sparing (standard nerve sparing as referent) wide dissection [OR: 0.96 (95% CI: 0.49, 1.88)], unilateral inter-/intrafascial [OR: 1.20 (95% CI: 0.70, 2.06)], bilateral inter-/intrafascial [OR: 1.97 (95% CI: 1.36, 2.86)], and PST bladder drainage at the time of surgery [OR: 2.53 (95% CI: 1.56, 4.11)] (Table 2).
Discussion
Few studies address the characteristics that predispose a patient to early return of continence. While the immediate return of continence is uncommon after RARP, it is not rare, and to our knowledge, there has been no study to date assessing this outcome. In this analysis, we examined the predictors of immediate continence and absence of pad usage after RARP.
Several characteristics of our study make the findings novel and applicable in clinical practice. Our study relied on a large heterogeneous population of individuals undergoing RARP by several surgeons with different levels of experience, and therefore we feel that it can be applied to the broad patient population. We have only included patients undergoing RARP, the most common extirpative therapy for prostate Cancer in the United States, 12 and we have also only included prospective data derived from patient-administered questionnaires. Studying numerous surgeons provides a unique opportunity to assess different operative techniques, including single-vs.-double-layer anastomosis and usage of PST for postoperative bladder drainage. While 611 were performed by the highest-volume surgeon (M.M.), 692 were performed by 4 surgeons (volume range: 16–395) over the study period.
In a study reflective of broad RARP practice at our institution, 17.3% (n=219) of patients were entirely pad free after RARP with no incontinence (Table 1). These patients tended to be younger, healthier, with a lower prostate weight. They also had more frequently undergone a bilateral nerve-sparing procedure (inter-/intrafascial), and subsequent PST bladder drainage. While all of these characteristics were predictive of early continence in a univariable fashion, only type of nerve sparing performed (bilateral inter/intrafascial) and placement of a PST for bladder drainage postoperatively were found to be independently predictive on multivariate analysis (Table 2). Surprisingly, surgeon volume, though predictive of early continence on univariable analysis, was not independently predictive on multivariable analysis. We attribute this finding to colinearity with nerve-sparing approach and PST placement.
We previously demonstrated that the degree of nerve sparing was predictive of long-term continence rates 1 year postoperatively 1 ; it is also an important predictor of immediate continence. This finding is consistent with previous reports from the RP literature demonstrating the association of the nerve-sparing technique and continence outcomes. Burkhard et al. found that attempted nerve sparing independently predicted long-term continence. 13 Ko et al. found age and type of nerve sparing to be independent predictors of early continence 3 months after RARP. 3 Finally, Novara et al. reported age and CCI to be independent predictors of the return of urinary continence after robotic and/or laparoscopic radical prostatectomy. 14 None of the above studies, however, looked specifically at patients with absence of pad usage immediately after surgery. It seems probable that maximal preservation of innervation plays an important role in long-term continence recovery, but continence 5–7 days postoperatively (at the time of catheter removal) is more likely related to periurethral tissue preservation. This seems to be most effective during a bilateral inter-/intrafascial nerve-sparing procedure as mentioned above.
We also demonstrated that placement of a PST is independently predictive of immediate continence. We hypothesize that decreased catheter-related patient discomfort and less anticholinergic medication usage may play a role. 10 Moreover, it can be argued that with the water-tight anastomosis achievable during RARP, the role of postoperative catheter drainage has evolved. It is no longer necessary to place a Foley catheter to prevent cross-healing, but rather to allow bladder drainage while postoperative inflammation at the anastomotic site subsides. Koch et al. hypothesized that transurethral catheterization may actually be deleterious as it is “plausible that prolonged catheterization may contribute to bladder neck or urethral strictures by the effect of a foreign object (catheter) on the inflammatory response”. 15 We hope that previous demonstrations of long-term safety and efficacy combined with the current findings of improved immediate continence demonstrate that splinting of the urethrovesical anastomosis is not a critical step of radical prostatectomy. 8
There are several limitations of this study. The primary outcome assessed was immediate continence without pad usage after RARP; this is a minority of the patient population, and those experiencing this outcome may not be broadly representative of the total RARP patient population. Additionally, a small, but non-negligible, subset of patients who undergo radical prostatectomy may already experience some baseline incontinence preoperatively requiring pad usage. We could not account for this group of patients in our dataset. Finally, although this is a multisurgeon study, it was performed at a single high-volume institution, and therefore several institutional factors may have influenced outcomes for all patients, and this may limit the studies generalizability. Finally, though we utilized a patient-administered questionnaire, the instrument has not been validated.
Conclusion
In a population of patients undergoing RARP by one of five surgeons at a single high-volume institution, 17.3% required no pad usage postoperatively, experiencing immediate return of continence. The type of nerve sparing and placement of a PST at the time of surgery for bladder drainage were found to be the only independently predictive factors of immediate continence after RARP. External validation is required to further assess the generalizability of these findings.
Footnotes
Disclosure Statement
No competing financial interests exist.