To elucidate the etiology of lower urinary tract symptoms (LUTS) after radical prostatectomy, the present study investigated associations between postoperative urethral and vesical anatomic features on magnetic resonance imaging (MRI) and LUTS.

Fifty consecutive patients undergoing radical prostatectomy also underwent preoperative and postoperative MRI. Preoperative MRI only evaluated preoperative membranous urethral length (MUL). Postoperative MRI evaluated postoperative MUL, posterior-urethral vesical angle, depth of the urethrovesical junction (UVJ), and urinary pooling inside the urethra and bladder neck configuration. At the same time as postoperative MRI, International Prostate Symptom Score (IPSS), quality of life index, continence grade, and uroflowmetry parameters were investigated. Associations between preoperative or postoperative MRI variables and questionnaire results or uroflowmetry were analyzed to examine the relationships between the morphology of urethral and vesical anatomic features and LUTS.

Preoperative and postoperative MRI variables were not significantly associated with IPSS total score or uroflowmetry results. Urinary pooling inside the urethra was significantly associated with urgency score in the IPSS (P = .005). Postoperative MUL (P <.001), depth of the UVJ (P = .002), and urinary pooling inside the urethra (P = .04) were significantly associated with continence grade.

Urinary pooling inside the urethra might induce urgency, and postoperative MUL and depth of UVJ were related to urinary incontinence. Avoiding damage to the nerves involved in continence to prevent inflow of urine into the urethra, preservation of MUL, and development of procedures to prevent descent of the bladder neck during surgery are therefore recommended.