Anatomy and Principles of Excision of the Prostate





Surgical Approaches


Radical prostatectomy remains a standard treatment option for men with localized prostate cancer. Even though this operation has developed over more than a century, it remains a challenging procedure. Thus, technical refinements and innovative surgical approaches continue to evolve in an attempt to maximize cancer control while simultaneously reducing treatment-related side effects. In terms of open surgery, the prostate may be approached from either a retropubic or perineal direction. Currently, radical retropubic prostatectomy remains the most commonly performed open surgical approach. This is due to a variety of reasons including familiarity with the anatomy, easy access to the pelvic lymph nodes, wide exposure to the pelvis, ability to identify and release the neurovascular bundles, and reduced risk of rectal injury. However, the widespread adoption of robotic-assisted laparoscopic radical prostatectomy has significantly reduced the utilization of the open approach. Consequently, this operation remains challenging and this is particularly true for those who only perform this surgery on an occasional basis.


The perineal approach, however, is also an important open technique that has potential advantages over the retropubic approach in experienced hands. Potential advantages of the perineal over a retropubic approach include a small hidden incision, less blood loss, and excellent posterior and apical exposure to limit positive margins in these areas and facilitate the urethrovesical anastomosis. One definite disadvantage of the perineal approach is the fact that, when indicated, the pelvic lymph node dissection (PLND) must be performed through a separate incision. This may be done either via a laparoscopic approach or small open (“minilap”) incision.


Laparoscopic, particularly robotic-assisted laparoscopic radical prostatectomy, is another important surgical approach that has rapidly achieved equivalence and has surpassed open surgical approaches at most centers. Potential advantages of these minimally invasive approaches over traditional open surgery include smaller incisions that, in addition to improved cosmetic appearance, allow for a more rapid return to physical activity. Moreover, significantly reduced blood loss and enhanced optical magnification could potentially result in improved postoperative functional outcomes. Most commonly, these procedures are performed from a transperitoneal approach with access anteriorly into the retropubic space, although it can be performed from a solely extraperitoneal approach as well.




Relationship to Adjacent Structures


Regardless of the surgical approach, a thorough understanding of prostate anatomy and its relationship to surrounding structures is essential. The prostate gland is located in the true pelvis and is attached to the undersurface of the pubic symphysis by the puboprostatic ligaments ( Fig. 72.1 ). Anteriorly, the puboprostatic ligaments are dense, fibrous connections that attach from the pubic bone to the prostate. They extend under the pubic bone and attach to the prostate and extend onto the urethra at the prostatourethral junction.




FIGURE 72.1


( A ) Prostatic relationships. ( B ) Prostate and adjacent structures, sagittal section. ( C ) Prostate in situ, transverse section.


The apex of the prostate is intimately related to the urogenital diaphragm. The striated urethral sphincter surrounds the membranous urethra at the prostatic apex and forms a horseshoe-shaped muscular sleeve around it. On the lateral aspect of the prostate, the prostate is covered by the pelvic fascia and bordered by the levator ani muscle. The inner investing layer of the levator ani fascia (endopelvic fascia) forms a fascial collar and is attached to the extraperitoneal connective tissue covering the prostate on its anterior and lateral aspects. Posteriorly, the Denonvilliers fascia is a thin layer of connective tissue that covers the prostate near the apex caudally and invests the seminal vesicles as it extends cranially.


At the apex, the prostate and membranous urethra are attached to the underlying rectum by the rectourethralis muscle, which extends laterally at the apex for a variable distance. The base of the prostate is intimately related to the bladder neck. The deepest portion of the trigone extends into the prostatic urethra. Consequently, the median lobe of the prostate may project into the bladder base and trigone. Posteriorly and cranially, the ampulla of the vas deferens and seminal vesicles are attached to the prostate base.




Arterial Blood Supply to the Prostate


The prostate receives its blood supply primarily from the prostatovesical artery ( Fig. 72.2 ). Although this artery has a well-defined trunk, it may be of variable origin and most commonly is derived from the gluteopudendal. The prostatovesical artery passes obliquely downward, forward, and medially along the anteroinferior surface of the bladder toward the prostate.


Jan 2, 2020 | Posted by in UROLOGY | Comments Off on Anatomy and Principles of Excision of the Prostate

Full access? Get Clinical Tree

Get Clinical Tree app for offline access