New England Section of the American Urological Association

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Predictors of Urethrovesical Leak on Cystogram after Robotic Assisted Retropubic Prostatectomy
Alexa Golden, BS1; Kristian Stensland, MD MPH2; David Canes, MD2; Alireza Moinzadeh, MD2; Karim Hamawy, MD2
1Tufts University School of Medicine, Boston, MA; 2Lahey Hospital and Medical Center, Burlington, MA

BACKGROUND: After robotic-assisted retropubic prostatectomy (RALP), some surgeons opt for routine cystograms postoperatively to assess for vesicourethral anastomotic leak. Currently, there are no widely accepted guidelines for obtaining post-prostatectomy cystograms. The present analysis aims to identify factors associated with leak and to lay the groundwork for a cost-effectiveness analyses of this post-operative exam.
METHODS: Clinical information for all patients undergoing RALP by two fellowship-trained surgeons from a single center between March 2015 and July 2016 was retrospectively collected; all patients during this period routinely received a cystogram 1-2 weeks post-prostatectomy. Relevant data were extracted from electronic medical records; patients with incomplete records were excluded from analysis. A leak was defined as any extravasation of contrast on post-op cystogram. A failed cystogram was defined as not having the foley catheter removed within 1 day of post-op cystogram. Binary factors were compared between leak and non-leak groups using Chi-squared or Fisher's Exact test, continuous measures were compared using Student's t-test. A multivariate logistic regression was performed to identify factors associated with leak on cystogram.
RESULTS: A total of 172 patients were included, of which 17 (9.9%) had a leak on cystogram, and 11 (6.4%) had their foley duration lengthened due to a failed cystogram. The included cohort had a median age of 61 (IQR 56-67) years and median BMI of 28.5 (IQR 26-29). With respect to Gleason score, the cohort comprised 16 (9%) 3+3, 91 (53%) 3+4, 35 (20%) 4+3, 17 (9.9%) 4+4, and 13 (7.6%) >4+4 disease. Median PSA was 6.3 (IQR 4.7-9.1) ng/ml, and median prostate volume was 40 (IQR 30-50) cc. Intraoperatively, 24 (14%) of patients had a bladder neck reconstruction, and 28 (16%) had minimal or no nerve sparing. On univariate analysis, only higher gleason score was associated with leak on cystogram, with >4+4 (5/13 leaks) and 4+4 (2/17 leaks) significantly more likely to leak than lower Gleason scores. There were no significant differences between leak and no-leak groups in average age, BMI, PSA, prostate volume, or operative time. There were no differences in rates of smoking status, CAD, CHF, diabetes, dyslipidemia, BPH, past abdominal or pelvic surgery, bladder neck reconstruction, nerve sparing, or positive margins. On multivariate analysis, only high Gleason score (>4+4) and minimal nerve sparing were associated with greater odds of a leak and/or cystogram failure (Table 1).
The rate of leak and leak requiring prolonged foley drainage after prostatectomy is relatively low. Patients with higher Gleason scores and/or minimal nerve sparing may warrant cystograms. Further cost-effectiveness analysis is underway to establish recommendations regarding which patients warrant the additional expense of a cystogram after prostatectomy.

Multivariate Model for Factors Associated with Odds of Leak
FactorOR95% CIp value
Prostate Volume1.020.98-1.070.27
Gleason 3+45.220.35-4230.34
Gleason 4+31.020.13-1000.99
Gleason 4+412.90.37-16000.21
> Gleason 4+467.62.41-82250.035

Table 1, Continued
Minimal Nerve Sparing54316-425670.001
<50% unilateral nerve sparing1.500.17-14.80.72
Bilateral Nerve Sparing2.960.34-380.35
Positive Margins1.820.36-8.60.45
Ever Smoker0.330.06-1.540.18
Bladder Neck Reconstruction4.330.64-310.13

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