Hypothesis / aims of study
Background:
Urinary incontinence (UI) following robot-assisted laparoscopic radical prostatectomy (RALRP) remains a significant cause of morbidity, adversely affecting the quality of life in patients treated for localized prostate cancer. Despite improvements in surgical technique and increased emphasis on functional outcomes, continence recovery varies considerably among patients. This has prompted the search for reliable anatomical and clinical predictors of postoperative continence. Multiparametric prostate magnetic resonance imaging (mpMRI) has emerged as a valuable tool in assessing pelvic anatomy, potentially allowing for prediction of functional outcomes such as urinary continence.
Objective:
This study aimed to evaluate the predictive value of anatomical parameters measured by preoperative mpMRI—including membranous urethral length (MUL), prostatic urethral length (PUL), and levator ani muscle thickness (LAMT)—as well as intraoperative robotic urethral length (RUL) on early and long-term urinary continence outcomes following RALRP.
Study design, materials and methods
Materials and Methods:
We conducted a retrospective cohort analysis of 89 patients who underwent RALRP between January 2018 and December 2023 at Hacettepe University Hospital. Patients with preoperative urinary incontinence, anastomotic strictures, or incomplete follow-up were excluded. Intraoperatively, MUL was measured using a sterile ruler introduced through a 12 mm trocar during apical dissection. Preoperative mpMRI data were available for 72 patients, from which PUL, MUL, and LAMT were measured using standardized T2-weighted sagittal and coronal sequences. All patients received structured postoperative pelvic floor physiotherapy. Continence was assessed using the International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form (ICIQ-UI SF), a 1-hour pad test, and patient-reported outcomes. Continence was defined as the use of no pad or a single dry precautionary pad per day. Early continence was defined as regaining continence within 90 days postoperatively.
Results
At one-year follow-up, 80.9% (n=72) of patients achieved continence, with 70.8% (n=51) of these achieving early continence within 90 days. Univariate analysis identified significant associations between continence recovery and PUL (p=0.037), prostate specimen weight (p=0.038), bilateral nerve-sparing surgery (p=0.005), radiotherapy (p=0.001), D’Amico risk classification (p=0.010), and pathological T stage (p=0.002). However, multivariate logistic regression identified only bilateral nerve-sparing surgery as an independent predictor of continence (p=0.037; OR=4.738; 95% CI: 1.100–20.405).
ROC analysis revealed that PUL had a statistically significant ability to predict early continence (AUC: 0.697; p=0.012), whereas MUL (AUC: 0.615), RUL (AUC: 0.631), and LAMT (AUC: 0.619) did not demonstrate significant predictive value (all p>0.05). Subgroup analysis further suggested that patients with PUL ≥ 44 mm were significantly more likely to achieve early continence.
Interpretation of results
This study underscores the importance of bilateral nerve-sparing technique as a modifiable factor strongly associated with long-term continence recovery following RALRP. Among the pre- and intraoperative anatomical measurements, prostatic urethral length measured via mpMRI emerged as the only reliable predictor of early return to continence. In contrast, membranous urethral length, robotic urethral length, and levator ani muscle thickness showed limited prognostic utility. These findings support the incorporation of PUL assessment into preoperative mpMRI evaluations to guide patient counseling and surgical planning. Future prospective studies with larger cohorts are warranted to confirm these results and further optimize individualized continence risk stratification.