Association Between Preoperative Magnetic Resonance Imaging–based Urethral Parameters and Continence Recovery Following Robot-assisted Radical Prostatectomy

A prospective study using questionnaires and urodynamic assessments to evaluate bladder function and continence changes after robotic assisted radical prostatectomy

Post-prostatectomy continence status, in addition to lower urinary tract symptoms, is a major concern among patients after robotic-assisted radical prostatectomy (RaRP). In this prospective study, we enrolled patients undergoing RaRP to evaluate subjective urinary symptoms and objective urodynamic parameters before and after surgery. Patients were recruited before RaRP surgery between January 2019 and August 2020. One day before surgery, the participants completed three questionnaires and pressure-flow studies, which were repeated approximately 3 months postoperatively. Of the total 135 patients initially enrolled, 85 (63.0%) completed the entire follow-up period. Three months after RaRP, the International Prostate Symptom Score showed significant increases in storage symptoms. Similar trends were observed in the Urinary Distress Inventory Short Form, and Overactive Bladder Symptom Score questionnaires. More than half of the patients regained continence within 2 months, although 9.6% remained incontinent after 1 year. Postoperative urodynamic studies indicated increased bladder hypersensitivity and significantly decreased detrusor pressure at peak flow. Furthermore, the bladder contractility index and bladder outlet obstruction index were reduced postoperatively. Ten patients (11.8%) developed de novo detrusor overactivity. The multivariate analysis identified age and cross-sectional area of the bladder neck as predictors of immediate continence after RaRP.

Association of bi-parametric MRI measures with continence after robot-assisted radical prostatectomy

OBJECTIVE

To investigate the association between pre- and postoperative magnetic resonance imaging (MRI) measurements of the membranous urethra and the prostate volume and continence following robot-assisted radical prostatectomy (RARP).

PATIENTS AND METHODS

From December 2018 to June 2022, 100 continent patients undergoing unilateral nerve-sparing or non-nerve-sparing RARP were included in this cohort study. Bi-parametric MRI scans were performed before and 12 months after RARP and measurements included the membranous urethral length (MUL) measured in cm (mMUL) and in the number of image slices (sMUL; 3 mm/slice), the membranous urethral diameter (MUD), and the prostate volume. Urinary function was evaluated by the International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form (ICIQ-UI SF) and continence, defined as the use of zero pads and the answer 'never' to the ICIQ-UI SF question regarding incontinence frequency or <8 g urine-loss per 24 h. Regression with robust variance estimates was used to analyse the association between measurements and outcomes.

RESULTS

At 12 months, continence and MRI data were available for 82 patients. The continence rate was 63% and the median (interquartile range) ICIQ-UI SF score was 4 (0-9). Both preoperative MUL measurements were associated with continence at 12 months. Every extra 5 mm of MUL increased the likelihood of being continent by 13 percentage points (P = 0.03) and every additional slice of sMUL increased it by 6 percentage points (P = 0.05). Both postoperative MUL measurements were associated with better continence and lower ICIQ-UI SF scores (P < 0.01). A larger prostate volume was associated with urinary incontinence at 12 months, with a small effect size. The MUD was not associated with continence.

CONCLUSION

Preoperative mMUL and sMUL are associated with continence at 12 months after RARP. The sMUL may be a useful measurement when only the axial plane is available, and the slice gap is known. Postoperative MUL measurements are strongly associated with continence, while MUD and prostate volume hold minimal prognostic value.

Bladder mucosal smoothness predicts early recovery of urinary continence after laparoscopic radical prostatectomy

BACKGROUND

To propose the bladder mucosal smoothness (BMS) grade and validate a predictive model including MRI parameters preoperatively that can evaluate the early recovery of urinary continence (UC) after laparoscopic radical prostatectomy (LRP).

METHODS

A retrospective analysis was conducted on 203 patients (83 patients experienced UI at the three-month follow-up) who underwent LRP in our medical center and were diagnosed with prostate cancer (PCa) from June 2016 to March 2020. Patients' clinicopathological data were collected. Prostate volume (PV), membranous urethra length (MUL), intravesical prostatic protrusion length (IPPL), and BMS grade were measured by MRI. The total sample was randomly divided into a training set (n = 142) and a validation set (n = 61). A model was developed to predict the risk of urinary incontinence (UI) at three months after LRP.

RESULTS

Age group, clinical T stage group, BMS grade group, PV group, IPPL group, and MUL group differed significantly between patients in the UI group and the UC group (all P values < 0.05). Multivariate analysis identified 3 MRI-related predictors selected for the prediction model: BMS grade (1 odds ratio [OR] 0.17, 95% CI 0.11-0.66; P value = 0.024) (2 + 3 OR 0.17, 95% CI 0.04-0.66; P value = 0.011), IPPL (> 5 mm OR 0.17, 95% CI 0.1-0.64; P = 0.004), and MUL (≥ 14 mm OR 6.41, 95% CI 2.72-15.09; P value < 0.001). The model achieved a highest area under the curve of 0.900 in the training set and the validation set. The sensitivity and specificity of the prediction model were 0.800 and 0.816.

CONCLUSION

Our study confirmed that patients with lower BMS grade are associated with early recovery of urinary continence after LRP. A prediction model was developed and validated to evaluate the early recovery of urinary continence after LRP.

CLINICAL TRIAL NUMBER

Not applicable.

Preoperative Prostate Magnetic Resonance Imaging-based Anatomical Predictors of Early Urinary Continence Following Single-port Transvesical Robot-assisted Radical Prostatectomy

BACKGROUND AND OBJECTIVE

The introduction of the single-port (SP) robotic system has led to new approaches in robot-assisted radical prostatectomy (RARP), such as the transvesical (TV) approach, offering high rates of early urinary continence. While previous studies of SP TV RARP have identified perioperative factors influencing continence outcomes, the impact of anatomical factors remains unexplored. This study aims to assess magnetic resonance imaging (MRI)-based anatomical predictors of urinary continence after SP TV RARP.

METHODS

A retrospective analysis of consecutive SP TV RARP cases (November 2020 to June 2023) with preoperative prostate MRI was performed. Two urogenital radiologists independently evaluated ten anatomical parameters to distinguish patients achieving urinary continence within 1 wk and 3 mo. Nonparametric methods estimated receiver operating characteristic curves (area under the curve [AUC]) and inter-reader agreement.

KEY FINDINGS AND LIMITATIONS

In 120 cases, 40% achieved continence within 1 wk, rising to 71.7% by 3 mo. Membranous urethra length (MUL) alone was significantly associated with continence at 3 mo (AUC: 0.67, p = 0.003). At 1 wk, several parameters, including anteroposterior diameter of the prostate, coronal membranous urethra length, prostate volume, and transverse diameter of the prostate, showed promise in predicting continence.

CONCLUSIONS AND CLINICAL IMPLICATIONS

A longer preoperative MUL was significantly associated with better odds of an early return to urinary continence after SP TV RARP. Each 1-mm increase in coronal MUL was associated with a 27% increase in the odds of continence at 3 mo. This information can aid in patient counseling and expectations preoperatively.

PATIENT SUMMARY

Urinary incontinence is a common outcome after prostate cancer surgery, particularly in the early months. Recently, the single-port (SP) robotic system has emerged, localizing surgery to the diseased area. With the SP robot, accessing the prostate via the bladder leads to high rates of early continence. Our study reveals that the longer the urethral portion beneath the prostate, the higher the likelihood of regaining continence within 3 mo after surgery.

Elevating precision: A thorough investigation of multiparametric prostate MRI for prolonged insights into early continence prediction after robot-assisted laparoscopic prostatectomy

BACKGROUND

While radical prostatectomy stands out as one of the most effective curative treatments for prostate cancer, it does come with annoying side effects, such as urinary incontinence (UI). We aimed to investigate the predictability of UI using MRI measurements, along with clinical and disease-related variables.

METHODS

We included 191 patients who underwent robot-assisted laparoscopic radical prostatectomy between July 2020 and October 2022 in the study. Preoperative MRIs of the patients are re-evaluated by an experienced uroradiologist, and membranous urethral length (MUL), urethra wall thickness, levator ani thickness, outer levator distance, Lee's apex shape, intravesical prostate protrusion length, prostate apex depth, and pubic height measurements were made. Additionally, retrospective data on patients' age, BMI, PSA, PSA density, prostate volume, IPSS, clinical stage, and nerve-sparing status were collected. Patients were categorized into two groups based on continence status in the third postoperative month: continent or incontinent. The definition of UI was accepted as the use of one or more pads per day.

RESULTS

UI was observed in 38.21 % of the patients in the postoperative third month. Among MRI measurements, only MUL showed a significant relationship with UI (p < 0.001). IPSS (p = 0.004) and Clinical Stage (p < 0.001) were also significantly associated with continence status. Logistic regression analysis identified BMI (p = 0.023; CI 0.73-0.97), IPSS (p = 0.002; CI 1.03-1.17), MUL (p = 0.001; CI 0.66-0.90), and Clinical Stage (p < 0.001; CI 1.53-2.71) as significant predictors. In Multivariable Regression analysis, Clinical Stage emerged as the most powerful predictor of UI (p < 0.001).

CONCLUSIONS

Except for MUL, MRI measurements may not predict postoperative UI. A combination of IPSS, clinical stage, and MUL effectively informs patients about postoperative outcomes. These findings contribute to enhancing preoperative counseling for patients undergoing radical prostatectomy.

Membranous urethral length is the single independent predictor of urinary continence recovery at 12 months following Retzius-sparing robot-assisted radical prostatectomy

The influence of anatomical parameters on urinary continence (UC) after Retzius-sparing robot-assisted radical prostatectomy (RS-RARP) remains uncharted. Our objective was to evaluate their association with UC at 3, 6 and 12 months post-operatively. Data from patients who underwent RS-RARP were prospectively collected. Continence was defined as no pad use. Anatomic variables were measured on preoperative magnetic resonance imaging (MRI). Regression analyses were performed to identify predictors of UC at each time point. We included 158 patients with a median age of 60 years, most of whom had a localized tumor (≤ cT2). On multivariate analyses, at 3 months post-surgery, urinary incontinence (UI) rises with age, odds ratio (OR) 1.07 [95% confidence interval (CI) 1.004-1.142] and with prostate volume (PV), OR 1.029 (95% CI 1.006-1.052); it reduces with longer membranous urethral length (MUL), OR 0.875 (95% CI 0.780-0.983) and with higher membranous urethral volume (MUV), OR 0.299 (95% CI 0.121-0.737). At 6 months, UI rises with PV, OR 1.033 (95% CI 1.011-1.056) and decreases with MUV, OR 0.1504 (95% CI 0.050-0.444). Significantly, at 12 months post-surgery, the only predictor of UI is MUL, OR 0.830 (95% CI 0.706-0.975), establishing a threshold associated with a risk of UI of 5% (MUL > 15 mm) in opposition to a risk of 25% (MUL < 10 mm). This single institutional study requires external validation. To our knowledge, this is the first prospective cohort study supporting MUL as the single independent predictor of UC at 12 months post-surgery. By establishing MUL thresholds, we enable precise patient counseling.

Membranous urethral length measurement on preoperative MRI to predict incontinence after radical prostatectomy: a literature review towards a proposal for measurement standardization

OBJECTIVES

To investigate the membranous urethral length (MUL) measurement and its interobserver agreement, and propose literature-based recommendations to standardize MUL measurement for increasing interobserver agreement. MUL measurements based on prostate MRI scans, for urinary incontinence risk assessment before radical prostatectomy (RP), may influence treatment decision-making in men with localised prostate cancer. Before implementation in clinical practise, MRI-based MUL measurements need standardization to improve observer agreement.

METHODS

Online libraries were searched up to August 5, 2022, on MUL measurements. Two reviewers performed article selection and critical appraisal. Papers reporting on preoperative MUL measurements and urinary continence correlation were selected. Extracted information included measuring procedures, MRI sequences, population mean/median values, and observer agreement.

RESULTS

Fifty papers were included. Studies that specified the MRI sequence used T2-weighted images and used either coronal images (n = 13), sagittal images (n = 18), or both (n = 12) for MUL measurements. 'Prostatic apex' was the most common description of the proximal membranous urethra landmark and 'level/entry of the urethra into the penile bulb' was the most common description of the distal landmark. Population mean (median) MUL value range was 10.4-17.1 mm (7.3-17.3 mm), suggesting either population or measurement differences. Detailed measurement technique descriptions for reproducibility were lacking. Recommendations on MRI-based MUL measurement were formulated by using anatomical landmarks and detailed descriptions and illustrations.

CONCLUSIONS

In order to improve on measurement variability, a literature-based measuring method of the MUL was proposed, supported by several illustrative case studies, in an attempt to standardize MRI-based MUL measurements for appropriate urinary incontinence risk preoperatively.

CLINICAL RELEVANCE STATEMENT

Implementation of MUL measurements into clinical practise for personalized post-prostatectomy continence prediction is hampered by lack of standardization and suboptimal interobserver agreement. Our proposed standardized MUL measurement aims to facilitate standardization and to improve the interobserver agreement.

KEY POINTS

• Variable approaches for membranous urethral length measurement are being used, without detailed description and with substantial differences in length of the membranous urethra, hampering standardization. • Limited interobserver agreement for membranous urethral length measurement was observed in several studies, while preoperative incontinence risk assessment necessitates high interobserver agreement. • Literature-based recommendations are proposed to standardize MRI-based membranous urethral length measurement for increasing interobserver agreement and improving preoperative incontinence risk assessment, using anatomical landmarks on sagittal T2-weighted images.

Automated pelvic MRI measurements associated with urinary incontinence for prostate cancer patients undergoing radical prostatectomy

BACKGROUND

Pelvic morphological parameters on magnetic resonance imaging (MRI), such as the membranous urethral length (MUL), can predict urinary incontinence after radical prostatectomy but are prone to interobserver disagreement. Our objective was to improve interobserver agreement among radiologists in measuring pelvic parameters using deep learning (DL)-based segmentation of pelvic structures on MRI scans.

METHODS

Preoperative MRI was collected from 167 prostate cancer patients undergoing radical prostatectomy within our regional multicentric cohort. Two DL networks (nnU-Net) were trained on coronal and sagittal scans and evaluated on a test cohort using an 80/20% train-test split. Pelvic parameters were manually measured by three abdominal radiologists on raw MRI images and with the use of DL-generated segmentations. Automated measurements were also performed for the pelvic parameters. Interobserver agreement was evaluated using the intraclass correlation coefficient (ICC) and the Bland-Altman plot.

RESULTS

The DL models achieved median Dice similarity coefficient (DSC) values of 0.85-0.97 for coronal structures and 0.87-0.98 for sagittal structures. When radiologists used DL-generated segmentations of pelvic structures, the interobserver agreement for sagittal MUL improved from 0.64 (95% confidence interval 0.28-0.83) to 0.91 (95% CI 0.84-0.95). Furthermore, there was an increase in ICC values for the obturator internus muscle from 0.74 (95% CI 0.42-0.87) to 0.86 (95% CI 0.75-0.92) and for the levator ani muscle from 0.40 (95% CI 0.05-0.66) to 0.61 (95% CI 0.31-0.78).

CONCLUSIONS

DL-based automated segmentation of pelvic structures improved interobserver agreement in measuring pelvic parameters on preoperative MRI scans.

RELEVANCE STATEMENT

The implementation of deep learning segmentations allows for more consistent measurements of pelvic parameters by radiologists. Standardized measurements are crucial for incorporating these parameters into urinary continence prediction models.

KEY POINTS

• DL-generated segmentations improve interobserver agreement for pelvic measurements among radiologists. • Membranous urethral length measurement improved from substantial to almost perfect agreement. • Artificial intelligence enhances objective pelvic parameter assessment for continence prediction models.

Variations in predictors for urinary continence recovery at different time periods following robot-assisted radical prostatectomy

INTRODUCTION

Urinary dysfunctions are common sequelae following prostatectomy. This study aimed to discover factors that can predict urinary continence recovery at various time periods after robot-assisted laparoscopic radical prostatectomy (RARP).

METHODS

This was a retrospective analysis of data of 419 consecutive patients. Only patients followed up for ≥1 year were enrolled. An answer of "zero pad per day" in the Expanded Prostate Cancer Index Composite urinary assessment (question 5) denoted continence. Possible predictors of urinary continence recovery were evaluated at 3, 3-6, and 6-12 months after the operation.

RESULTS

Continence rates at 3, 6, and 12 months after RARP were 12.9%, 21.2%, and 40.2%, respectively. The proportions of patients using 0-1 pad were 54.2%, 75.7%, and 83.1% at 3, 6, and 12 months after RARP, respectively. Multivariable regression analysis revealed that a membranous urethral length (MUL) ≥11 mm was significantly associated with urinary continence recovery both within 3 months (odds ratio: 0.367, P = .003) and 3-6 months (odds ratio: 0.354, P = .001) after RARP. The analysis also revealed that, in patients with urinary continence at 6 months, a large prostate volume (odds ratio: 1.973, P = .044) and a high body mass index (odds ratio: 2.874, P = .027) were negative predictors of urinary continence recovery within 6-12 months.

CONCLUSION

A longer MUL was linked to urinary continence recovery within 6 months following RARP, whereas a large prostate volume and a high body mass index were adverse predictors of urinary continence recovery beyond 6 months.

Prostate MRI for Improving Personalized Risk Prediction of Incontinence and Surgical Planning: The Role of Membranous Urethral Length Measurements and the Use of 3D Models

Prostate MRI has an important role in prostate cancer diagnosis and treatment, including detection, the targeting of prostate biopsies, staging and guiding radiotherapy and active surveillance. However, there are other ''less well-known'' applications which are being studied and frequently used in our highly specialized medical center. In this review, we focus on two research topics that lie within the expertise of this study group: (1) anatomical parameters predicting the risk of urinary incontinence after radical prostatectomy, allowing more personalized shared decision-making, with special emphasis on the membranous urethral length (MUL); (2) the use of three-dimensional models to help the surgical planning. These models may be used for training, patient counselling, personalized estimation of nerve sparing and extracapsular extension and may help to achieve negative surgical margins and undetectable postoperative PSA values.

Inter-observer variability in male pelvic-floor MRI measurements that might predict post-prostatectomy incontinence

INTRODUCTION

Current studies are focusing on the relationship between anatomical variables in preoperative prostate MRI and the development of post-prostatectomy incontinence (PPI). Nevertheless, there is little evidence regarding the reliability of these measurements. The objective of this study was to analyze the concordance between urologists and radiologists for anatomical measurements that might be PPI predictors.

MATERIAL AND METHODS

Pelvic floor measurements with 3T-MRI were performed by two radiologists and two urologists independently and blindly. Interobserver agreement was determined using the intraclass correlation coefficient (ICC) and the Bland-Altman plot.

RESULTS

The concordance was good-acceptable for most measurements, except for the levator ani and puborectalis muscle thickness (some ICC values  < 0.20/p value > 0.05). The anatomical parameters with the highest degree of agreement were intravesical prostatic protrusion (IPP) and prostate volume (most of the ICC values > 0.60). The membranous urethral length (MUL) and the angle of the membranous urethra-prostate axis (aLUMP) presented ICC > 0.40. The obturator internus muscle thickness (OIT), urethral width and intraprostatic urethral length presented a fair-moderate degree of agreement (ICC > 0.20). Regarding the agreement between different specialists, the highest degree was obtained for the two radiologists and for urologist 1-radiologist 2 (moderate median agreement), while urologist 2 with each of the radiologists had a regular median agreement.

CONCLUSIONS

MUL, IPP, prostate volume, aLUMP, OIT, urethral width and prostatic length show acceptable inter-observer concordance and they would be reliable as possible predictors of PPI. Levator ani and puborectalis muscle thickness show bad agreement. Interobserver agreement might not be greatly influenced by previous professional experience.

Prediction of recovery time of urinary incontinence following robot-assisted laparoscopic prostatectomy

OBJECTIVES

Postoperative urinary incontinence recovery following robot-assisted laparoscopic prostatectomy is an important outcome. We investigated whether factors that affect urinary incontinence can predict the duration of postoperative incontinence recovery.

METHODS

A total of 310 patients underwent robot-assisted laparoscopic prostatectomy. Continence recovery was defined as either pad-free or a safety pad only status. Univariate and multivariate analyses were performed on clinical variables to identify those that were associated with continence recovery. A scoring system to predict recovered continence was constructed using statistically significant variables. The validity of this tool was tested in a new cohort of 273 patients.

RESULTS

Factors associated with recovery of urinary incontinence were membranous urethral length, preservation of bilateral neurovascular bundles, and a preoperative Prostate Imaging Reporting and Data System score of ≥3 in the apex. Age was related only to incontinence recovery at 1 month. To prepare the score, weighting was performed using the estimated values. Using the developed scoring system, participants in the verification set were divided into three groups. The early recovery group had a median incontinence recovery of 4 (4-12) weeks, the medium recovery group, 12 (4-24) weeks, and the late recovery group, 24 (24-48) weeks, which was a significant difference (p < 0.001).

CONCLUSIONS

The applied scoring system based on preoperative factors related to incontinence and derived from patient groups was significantly associated with continence recovery time. In patients undergoing robot-assisted laparoscopic prostatectomy, our unit-weighted regression model of clinical variables can predict the duration of continence recovery.

A standardized method to measure the membranous urethral length (MUL) on MRI of the prostate with high inter- and intra-observer agreement

OBJECTIVES

The membranous urethral length (MUL), defined as the length between the apex and penile base as measured on preoperative prostate magnetic resonance imaging (MRI), is an important predictor for urinary incontinence after radical prostatectomy. Literature on inter- and intra - observer agreement of MUL measurement is limited. We studied the inter- and intra-observer agreement between radiologists using a well-defined method to measure the MUL on the prostate MRI.

METHODS

Prostate cancer patients underwent a preoperative MRI and robot-assisted radical prostatectomy (RARP) at one high-volume RARP center. MUL measurement was based on well-defined landmarks on sagittal T2-weighted (anatomical) images. Three radiologists independently performed MUL measurements retrospectively in 106 patients blinded to themselves, to each other, and to clinical outcomes. The inter- and intra-observer agreement of MUL measurement between the radiologists were calculated, expressed as intra-class correlation coefficient (ICC).

RESULTS

The initial inter-observer agreement was ICC 0.63; 95% confidence interval (CI) 0.28-0.81. Radiologist 3 measured the MUL mean 3.9 mm (SD 3.3) longer than the other readers, interpreting the caudal point of the MUL (penile base) differently. After discussion on the correct anatomical definition, radiologist 3 re-assessed all scans, which resulted in a high inter-observer agreement (ICC 0.84; 95% CI 0.66-0.91). After a subsequent reading by radiologists 1 and 2, the intra-observer agreements were ICC 0.93; 95% CI 0.89-0.96, and ICC 0.98; 95% CI 0.97-0.98, respectively. Limitation is the monocenter design.

CONCLUSIONS

The MUL can be measured reliably with high agreement among radiologists.

KEY POINTS

• After discussion on the correct anatomical definition, the inter- and intra - observer agreements of membranous urethral length (MUL) measurement on magnetic resonance imaging (MRI) were high. • A reproducible method to measure the MUL can improve the clinical usefulness of prediction models for urinary continence after RARP which may benefit patient counselling.

Nightmares in Salvage Robot-assisted Radical Prostatectomy After Primary Radiation Therapy for Prostate Cancer: A Step by Step Tutorial

Salvage radical prostatectomy after primary radiotherapy (sRP) is considered a challenging procedure. We highlight the complications of sRP and detail critical surgical steps to help prevent them. A nonsystematic literature review in PubMed using the term “salvage radical prostatectomy” was performed on December 1, 2021. Salvage robot-assisted RP (sRARP) cases and imaging materials were used to create an educational video providing practical examples. Owing to radiation-induced changes in the prostate and surrounding tissues after radiotherapy, sRP is typically more challenging than primary RP. Among its critical steps are incision of the endopelvic fascia, bladder neck dissection with attempts at sparing the neck, development of posterior planes between the prostate and rectum, and dissection of the prostatic apex. Complication rates are significant, in particular for bladder neck contracture (0–16%) and anastomotic leakage (10–33%). Rectal injury is now rare (<2%) but still feared; careful adherence to surgical principles is required to avoid this complication. Functional outcomes are nonoptimal, with a high risk of urinary incontinence (severe incontinence in ∼25% of men). sRARP is a challenging urological procedure and should be performed by experienced surgeons. Thorough knowledge of the surgical anatomy and a meticulous technique for the most difficult surgical steps are crucial to minimise complications and to improve patient outcomes.

Patient summary

In patients with prostate cancer, removal of the prostate because of cancer recurrence after primary treatment with radiotherapy can be difficult because of radiation-induced tissue damage. This challenging procedure should be performed by experienced surgeons to minimise the risk of complications.

Value of Different Magnetic Resonance Imaging-based Measurements of Anatomical Structures on Preoperative Prostate Imaging in Predicting Urinary Continence After Radical Prostatectomy in Men with Prostate Cancer: A Systematic Review and Meta-analysis

CONTEXT

Measurements of anatomical structures on preoperative prostate magnetic resonance imaging (MRI) are used in risk models for treatment decisions to predict urinary continence (UC) following radical prostatectomy (RP). However, the association between these parameters and UC is unclear.

OBJECTIVE

To systematically summarize the literature on prognostic preoperative prostate MRI measurements of (peri)prostatic structures in relation to time to recovery of postoperative UC in men with prostate cancer.

EVIDENCE ACQUISITION

Online libraries were searched up to August 27, 2021. Article selection and critical appraisal were performed by two reviewers. All papers reporting on preoperative MRI measurements with UC correlation in univariable or multivariable analyses were included.

EVIDENCE SYNTHESIS

In the 50 studies included (mostly retrospective), 57 MRI parameters were evaluated. The pooled analyses showed that greater membranous urethra length (MUL) was prognostic for regaining UC at 1 mo (odds ratio [OR] 1.15, 95% confidence interval [CI] 1.10-1.21), 3 mo (OR 1.23, 95% CI 1.16-1.31), 6 mo (OR 1.16, 95% CI 1.08-1.25), and 12 mo (OR 1.19, 95% CI 1.10-1.29). Several other anatomical structures showed at least in one study a significant correlation with later return to UC: four prostate-related parameters (greater depth, apical protrusion, larger intravesical protrusion, small dorsal vascular complex), five urethra-related parameters (thicker wall, severe fibrosis, smaller volume, larger preoperative angle between the prostate axis and membranous urethra, shorter minimal residual MUL), and six musculoskeletal-related parameters (lower perfusion ratio, thinner levator ani muscle, larger inner or outer levator distance, shorter pelvic diaphragm length, and larger midpelvic area).

CONCLUSIONS

Greater MUL as measured on preoperative MRI was an independent prognostic factor for return to UC within 1 mo after RP and remained prognostic at 12 mo. Other anatomical structures may potentially be predictive, but these would need to be substantiated in prospective trials before being adopted in postoperative UC risk models for treatment decisions in men with prostate cancer.

PATIENT SUMMARY

We summarized study data on the relation between measurements of anatomical structures on preoperative magnetic resonance imaging scans and urinary continence after removal of the prostate. Greater length of one part of the urethra (membranous urethra) is associated with faster return to continence. Other anatomical structures have potential for predicting postoperative continence, but need further investigation.

Urethral Sphincter Length but Not Prostatic Apex Shape in Preoperative MRI Is Associated with Mid-Term Continence Rates after Radical Prostatectomy

Background: To test the impact of urethral sphincter length (USL) and anatomic variants of prostatic apex (Lee-type classification) in preoperative multiparametric magnet resonance imaging (mpMRI) on mid-term continence in prostate cancer patients treated with radical prostatectomy (RP). Methods: We relied on an institutional tertiary-care database to identify patients who underwent RP between 03/2018 and 12/2019 with preoperative mpMRI and data available on mid-term (>6 months post-surgery) urinary continence, defined as usage 0/1 (-safety) pad/24 h. Univariable and multivariable logistic regression models were fitted to test for predictor status of USL and prostatic apex variants, defined in mpMRI measurements. Results: Of 68 eligible patients, rate of mid-term urinary continence was 81% (n = 55). Median coronal (15.1 vs. 12.5 mm) and sagittal (15.4 vs. 11.1 mm) USL were longer in patients reporting urinary continence in mid-term follow-up (both p < 0.01). No difference was recorded for prostatic apex variants distribution (Lee-type) between continent vs. incontinent patients (p = 0.4). In separate multivariable logistic regression models, coronal (odds ratio (OR): 1.35) and sagittal (OR: 1.67) USL, but not Lee-type, were independent predictors for mid-term continence. Conclusion: USL, but not apex anatomy, in preoperative mpMRI was associated with higher rates of urinary continence at mid-term follow-up.

Anatomical predictors of long-term urinary incontinence after robot-assisted laparoscopic prostatectomy: A systematic review

AIMS

There is scarce evidence of anatomical risk factors that might affect long-term post-prostatectomy incontinence (PPI) in patients undergoing robot-assisted laparoscopic prostatectomy (RALP). This systematic review aims to identify anatomical measurements in preoperative magnetic resonance imaging (MRI) that might be associated with increased risk of urinary incontinence (UI) 1 year after RALP.

METHODS

A comprehensive search on Pubmed and Scopus databases up to November 2020 was performed. Eight articles met the inclusion criteria and were finally selected.

RESULTS

The selected studies included 1146 patients. Seven articles focused on membranous urethral length (MUL); all of them related MUL to long-term PPI in univariate analysis and five of them in multivariate analysis. Four studies presented MUL difference to measure the magnitude of the effect. Average MUL (mm) was 15.9 (SD, 2.6), 16.1 (95% confidence interval [CI]: 13.9-18.9), 12.1 (95% CI 9.7-14.9) and 14.5 in continent patients and 13.9 (SD, 2.9), 10 (95% CI: 8.7-12.1), 10.3 (95% CI: 8.7-12.4) and 9.3 in incontinent patients, with statistically significant differences in all cases. Five studies presented the odds ratio as a result; although there was substantial heterogeneity in the methods used to obtain it, there was consistency in finding an inverse association between MUL and PPI. Other measurements including prostatic-urethral angle, membranous urethral thickness, intraprostatic urethral length and intravesical prostatic protrusion have been reported in few studies, and no association with long-term PPI was found. Levator ani muscle thickness was related to long-term PPI in one article.

CONCLUSION

Greater MUL on preoperative MRI is associated with lower risk of UI 1 year after RALP.

Daily urine loss immediately after urethral catheter removal may be an effective predictor of long-term urinary incontinence following robot-assisted laparoscopic radical prostatectomy

PURPOSE

Some patients who undergo robot-assisted laparoscopic radical prostatectomy (RARP) continue to experience long-term urinary incontinence (UI). This study aimed to evaluate easily obtainable factors that can predict long-term UI following RARP.

MATERIALS AND METHODS

A total of 315 patients who underwent RARP for localised prostatic cancer were analysed. We separated the patients into two groups, namely, the Continence group and the Incontinence group, according to the presence or absence of UI at 12 months after surgery, and we compared the patients' characteristics and operative data to identify clinical signs associated with long-term UI. Additionally, correlations between these factors and postoperative urethral function were evaluated. Urinary continence was defined as both the use of 0 pads/per day and <2 g of urine lost using the 24-hours pad weight test.

RESULTS

Of 315 patients, 250 (79.4%) achieved urinary continence and 65 (20.6%) had long-term UI. Age, storage-related lower urinary tract symptoms before surgery, nerve-sparing surgery and the 24-hours urine loss immediately after urethral catheter removal significantly affected long-term UI after RARP. Multivariate logistic regression analyses revealed that the 24-hours urine loss after catheter removal was a significant predictor of long-term UI. Receiver operating characteristic curve analysis identified a urine loss of 330 g/d as the optimal cut-off value, which yielded 92% sensitivity and 84% specificity, and it showed significant correlations with postoperative urethral function and the time to recover urinary continence.

CONCLUSION

The 24-hours urine loss immediately after urethral catheter removal may be the most reliable and useful predictor of long-term UI following RARP.

Effect of prostatic apex shape (Lee types) and urethral sphincter length in preoperative MRI on very early continence rates after radical prostatectomy

Purpose

To test the effect of anatomic variants of the prostatic apex overlapping the membranous urethra (Lee type classification), as well as median urethral sphincter length (USL) in preoperative multiparametric magnetic resonance imaging (mpMRI) on the very early continence in open (ORP) and robotic-assisted radical prostatectomy (RARP) patients.

Methods

In 128 consecutive patients (01/2018–12/2019), USL and the prostatic apex classified according to Lee types A–D in mpMRI prior to ORP or RARP were retrospectively analyzed. Uni- and multivariable logistic regression models were used to identify anatomic characteristics for very early continence rates, defined as urine loss of ≤ 1 g in the PAD-test.

Results

Of 128 patients with mpMRI prior to surgery, 76 (59.4%) underwent RARP vs. 52 (40.6%) ORP. In total, median USL was 15, 15 and 10 mm in the sagittal, coronal and axial dimensions. After stratification according to very early continence in the PAD-test (≤ 1 g vs. > 1 g), continent patients had significantly more frequently Lee type D (71.4 vs. 54.4%) and C (14.3 vs. 7.6%, p = 0.03). In multivariable logistic regression models, the sagittal median USL (odds ratio [OR] 1.03) and Lee type C (OR: 7.0) and D (OR: 4.9) were independent predictors for achieving very early continence in the PAD-test.

Conclusion

Patients’ individual anatomical characteristics in mpMRI prior to radical prostatectomy can be used to predict very early continence. Lee type C and D suggest being the most favorable anatomical characteristics. Moreover, longer sagittal median USL in mpMRI seems to improve very early continence rates.

Anastomosis quality score during robot-assisted radical prostatectomy: a new simple tool to maximize postoperative management

PURPOSE

The urethro-vesical anastomosis represents one of the most challenging steps of robotic prostatectomy (RARP). To maximize postoperative management, we specifically designed our anastomosis quality score (AQS), based on the intraoperative characteristics of the urethra and bladder neck.

METHODS

This is a prospective study, conducted from April 2019 to March 2020. All the patients were classified into three different AQS categories (low, intermediate, high) based on the quality of the anastomosis. The postoperative management was modulated accordingly.

RESULTS

We enrolled 333 patients. According to AQS, no differences were recorded in intraoperative complications (p = 0.9). Median hospital stay and catheterization time were longer in AQS 1 group (p < 0.001). Additionally, the occurrence of postoperative complication was higher in AQS 1 category (p = 0.002) but, when focusing on the complications related to the quality of the anastomosis, no differences were found neither for acute urinary retention (p = 0.12) nor urine leakage (p = 0.11). Finally, concerning the continence recovery, no significant differences were found among the three groups for each time point. The highest potency recovery rate at one month of follow-up was recorded in AQS 3 category (p = 0. 03).

CONCLUSION

The AQS proposed revealed to be a valid too to intraoperatively categorize patients who underwent RARP on the basis of the urethral and bladder neck features. The modulated postoperative management for each specific score category allowed to limit the occurrence of complications and to maximize the functional outcomes.