Identification of the retrotrigonal layer as a key anatomical landmark during robotically assisted radical prostatectomy.
OBJECTIVE
To define the gross and microscopic anatomy, and the surgical significance, of the newly described retrotrigonal layer of the bladder neck, as an aid during robotic radical prostatectomy (RRP).


METHODS
The data for this study were obtained from five fresh cadaveric dissections and 100 consecutive RRPs. Five male cadavers with no previous pelvic or urethral surgery were dissected to expose the posterior bladder neck and identify the retrotrigonal layer. This same layer was reproducibly identified in all 100 RRPs. The gross appearance of this layer, and its relationship to neighbouring structures, was documented using still photographs and intraoperative video. The microscopic composition of this layer was assessed using routine haematoxylin and eosin stains, and special staining for smooth muscle (desmin), neural tissue (S-100), and elastin.


RESULTS
Grossly, the retrotrigonal layer is a well-defined midline strip located posterior to the bladder neck, that extends from the trigone (superiorly) to the base of the prostate (inferiorly). Microscopically, this layer was predominantly composed of smooth muscle with intervening connective tissue. The retrotrigonal layer serves as a key anatomical landmark to facilitate posterior prostatic dissection, particularly in men with large prostates, prominent median lobes, or previous transurethral prostatic surgery. Further, in our practice, this layer marks the posterior limit of dissection in which electrocautery is still used. Finally, the retrotrigonal layer serves to buttress the posterior layer of the urethrovesical anastomosis.


CONCLUSIONS
The retrotrigonal layer is a key landmark during the posterior bladder neck dissection in the antegrade technique of RRP.
Tewari
Ashutosh
A
Department of Urology, The New York-Presbyterian Hospital, Weill Medical College of Cornell University, New York, NY 10021, USA. akt2001@med.cornell.edu
El-Hakim
Assaad
A
Rao
Sandhya
S
Raman
Jay D
JD
D000328:Adult; D000368:Aged; D002102:Cadaver; D006801:Humans; D008297:Male; D008875:Middle Aged; D011468:Prostatectomy / Q000295:instrumentation / Q000592:standards*; D011471:Prostatic Neoplasms / Q000473:pathology / Q000601:surgery*; D012371:Robotics; D001743:Urinary Bladder / Q000033:anatomy & histology*