Category: Laparoscopic/ Robotic: Prostate

MP15-7 - Influence of morphological variation of prostate base in lateral approach of bladder neck dissection during robot-assisted radical prostatectomy.

Sat, Sep 22
10:00 AM - 12:00 PM

Introduction & Objective : Bladder neck dissection is an important step in robot-assisted radical prostatectomy (RARP), and occasionally we experience difficult cases. Thus we evaluated clinical factors affecting difficulty of bladder neck dissection during RARP, especially morphological evaluation of base of the prostate by MRI.


Methods :

We retrospectively analyzed 74 patients who underwent RARP by single surgeon between December 2015 and May 2018 at our institution. Using the da Vinci Si surgical system in all cases, lateral approach of bladder neck dissection was performed. First incision was initiated in the limit between detrusor and base of the prostate, lateral to the pubovesical ligaments. While keeping the layer of anterior surface of seminal vesicle, incision of bladder neck was proceeded to posterior layer of urethra. Then urethra and remaining detrusor were dissected according to the layer of base of the prostate and anterior surface of seminal vesicle. MRI was performed before surgery in all cases, and the transverse diameter of bladder neck, the longitudinal diameter of bladder neck and the depth of urethra were measured. Then we analyzed the clinicopathological factors correlated with time of bladder neck dissection.


Results :

Positive surgical margin (PSM) rate of T2 patients was 1.9%, and PSM rate of T3 patients was 23.8%. There was no case of PSM at the base of the prostate. The median transverse diameter of the bladder neck on the preoperative MRI was 37.71 mm. The median longitudinal diameter, ventral depth of urethra and dorsal depth of urethra wewe 32.06 mm, 16.33 mm and 14.59 mm, respectively. The median time of bladder neck dissection was 22 minutes. In multivariate analysis, the BMI and the transverse diameter of the bladder neck significantly correlated with the time taken for the bladder neck dissection.


Conclusions : The lateral approach of bladder neck dissection was influenced by the transverse diameter of bladder neck and BMI. Meanwhile, morphological variation of prostate base did not affect this approach. Thus, the lateral approach of bladder neck dissection may contribute to RARP in case of various forms of prostate base.

Tomoaki Hakariya

Assistant professor
Department of Urology, Nagasaki University
Nagasaki, Nagasaki, Japan

I am a urologist belonging to the department of urology at Nagasaki University. My name is Tomoaki Hakariya, MD, PhD.

Yohei Shida

Nagasaki, Nagasaki, Japan

Yasuyoshi Miyata

Nagasaki, Nagasaki, Japan

Hideki Sakai

Nagasaki, Nagasaki, Japan