Blood flow may influence lower urinary function after surgery for prostate cancer. (Ref #1-3) However, it is difficult to evaluate the blood flow at bladder neck or urethral sphincter, and outcome of blood supply preservation has not been investigated well yet. Therefore, the role of blood supply preservation still has been unclear after prostatectomy. On the other hand, we discovered increase of blood flow in peri-bladder-neck including prostate at urine micturition using ultrasonography. Herein, we investigated the association of lower urinary tract function after prostatectomy and pre- and post-operative blood flow in peri-bladder-neck under urine micturition.

This study was conducted as a prospective observative study. Prostate cancer patients were enrolled in this trial before radical prostatectomy, and all of the enrolled patients were received robot assisted radical prostatectomy without nerve sparing technique. Transrectal ultrasonography was done with color Doppler ultrasonography (CDUS) just 2 days before and 7 days after the surgery. The patients were put on the fluoroscopic tilting table for passive postural change from spine to standing position, and ultrasonographic findings on peri-bladder-neck including prostate was recorded as movies under urine micturition under CDUS. (Figure 1A) The peak blood flow was captured as an image. Three urological experts judged the blood flow under micturition on all of the captured images, and ranked the ultrasonographic images of the patients. In accordance with the ranking judged by the 3 experts, the enrolled patients were divided into “good” or “bad” in 1 : 1 ratio. The patients with 2 “good” or 3 “good” are treated as “good blood flow”. And, the patients with 1 “good” or zero “good” are treated as “bad blood flow”. All of clinical parameters were evaluated before and 1, 3, 6, 9, 12 months after surgery. International prostate symptom score (IPSS), International Consultation on Incontinence Questionnaire-Short Form (ICIQ-SF), uroflowmetry (Qmax) and post-voided residual urine (PVRU) were measured. Basic clinical characteristics and each parameters were compared between the group using unpaired t-tests.

A total of 14 patients were enrolled in this study. The representative findings of CDUS were shown in Figure 1(B-E). Increase of blood flow in the peri-bladder-neck including prostate can detected under urine micturition. The basic clinical characteristics did not change statistically besides prostate volume between good and bad blood flow after surgery. The prostate volume of good blood flow after surgery is more than bad blood flow after surgery group. The results of clinical parameters were shown in Figure 2. The increase of IPSS is more in the good blood flow than bad blood flow before surgery in 1, 3, 6, 9, 12 months after surgery statistically (p < 0.05). (Figure 2A) On the contrary, there are no statistical differences in any other clinical parameters among the groups. (Figure 2B-D) Moreover, the clinical parameters did not change between good and bad blood flow after surgery in all of the process of this trial. (Figure 2E-H)

The increase of blood flow on the peri-bladder-neck after prostatectomy may not be influenced by age or lower urinary tract function but by the prostate volume. The patients with large prostate showed good blood flow on peri-bladder-neck after prostatectomy. The IPSS increased statistically in the patient with good blood flow before surgery. The increase of blood flow after surgery did not influence on any clinical parameters in this study. These results indicate that the amount of blood flow depends on presurgical conditions of prostate, and the preservation of blood flow may not influence on lower urinary tract function after surgery. On the contrary, the excessive blood supply may have negative impact on lower urinary tract function after prostatectomy. However, there are some limitations in this trial. First, this trial was conducted with small number of the patients. Second, nerve sparing surgery did not done in this series. Third, only macro-level blood flow can be detected under CDUS. Therefore, micro-level evaluation should be done for blood supply after surgery. Considering all of the limitation, the results of this trial contained unique approach and interesting findings about pre- and post-operative blood flow on peri-bladder-neck before and after prostatectomy. Further evaluation are needed to evaluate exact role of blood supply preservation after prostatectomy.

Prostate volume might be influenced on blood flow preservation after prostatectomy. Moreover, blood flow preservation may not be an essential factor to improve lower urinary tract symptoms after prostatectomy at least about blood flow which can be detected by CDUS.

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