Archive for July, 2019

Prostate Neuro-Vascular Bundles (NVB): What You Need to Know About These Vital Structures

July 27, 2019

Andrew Siegel MD  7/27/2019

The prostate neuro-vascular bundles (NVB) are paired structures that provide nerve and blood supply to the erectile chambers of the penis, the prostate gland, the urethra, the rectum, and the pelvic floor muscles (levator ani muscles).  The NVB are formed by branches of pelvic nerves that unite with blood vessels (both arteries and veins). The NVB are contained within leaves of connective tissue and course down the sides of the prostate near the junction of the prostate and rectum.The NVB are of particular importance with respect to sexual function since they contain the nerve control for initiating the erectile response as well as the emission (passage of seminal fluid into the urethra) and ejaculation of semen.

Nerve sparing approach to RALP

When a robotic-assisted laparoscopic prostatectomy (RALP) is performed to treat prostate cancer, a nerve sparing approach is performed– whenever possible– to maximize the potential for erectile function and urinary control.  The challenge is that each NVB is delicate and has an intimate anatomic relationship to the prostate and can easily be traumatized. If an area of cancer extension beyond the prostate capsule is recognized at the time of robotic-assisted laparoscopic prostatectomy, all measures are taken to remove the cancer completely, often requiring “incremental” nerve sparing, tailored to the degree of cancer extension, which can range from partial nerve sparing to completely sacrificing the NVB.

NVB copy

Robotic assisted laparoscopic prostatectomy: note prostate has been removed, a catheter is placed within the urethra, each NVB has been well preserved, and the bladder neck has yet to be sewn to the urethral stump.  Image courtesy of Dr. Mutahar Ahmed.

Why do men after RALP develop erectile dysfunction?

Medical speak: The main etiology of post-radical prostatectomy ED is injury to the cavernous nerves, resulting in degeneration of nitric oxide synthase-containing axons and loss of nerve function.  This neuropraxia prevents normal and nocturnal erections, inducing hypoxia within the cavernosal tissues and resultant structural changes, including apoptosis of smooth muscle cells and eventual corporal fibrosis.

Haney et al, Journal of Sexual Medicine 2019; 16: 383-393

Translation into English!: The key cause of erection issues following prostatectomy is NVB trauma resulting in impaired nerve function.  This prevents erotic-induced, touch-induced, and spontaneous sleep-time erections.  The resultant diminished blood flow to the penis reduces delivery of oxygen and other vital nutrients to the erectile tissues, causing decline and death of the cells within the erectile tissues responsible for erections, ultimately giving rise to erectile tissue scarring and impaired erectile function.

Sexual Recovery After RALP

Sexual recovery following prostatectomy is typically a slow and gradual process that can be facilitated by a penile rehabilitation program (a separate topic for a later entry).  It is important to know that the nerve-sparing approach does not absolutely guarantee the recovery of erections in all patients. However, a young man with good sexual function and no medical co-morbidities who has a nerve sparing procedure on each side will have  a 85-90% chance or so of regaining penetrable erections one year following RALP (perhaps requiring oral ED medications). This percentage will be less when only one side is spared. Excising the NVB on both sides will result in erectile dysfunction in virtually all men.

Bottom Line: Male sexual function is contingent upon the all-important neuro-vascular bundles.  Every effort to preserve these structures is pursued when a robotic-assisted laparoscopic prostatectomy is performed, as long as the nerve sparing does not comprise the intent of the operation, which is to remove the cancer completely and cure the disease. Technical advances in the operation have resulted in vast improvement in the ability to spare the NVB and preserve sexual function.

Wishing you the best of health,

2014-04-23 20:16:29

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Dr. Andrew Siegel is a physician and urological surgeon who is board-certified in urology as well as in female pelvic medicine and reconstructive surgery.  He is an Assistant Clinical Professor of Surgery at the Rutgers-New Jersey Medical School and is a Castle Connolly Top Doctor New York Metro Area, Inside Jersey Top Doctor and Inside Jersey Top Doctor for Women’s Health. His mission is to “bridge the gap” between the public and the medical community. He is a urologist at New Jersey Urology, the largest urology practice in the United States.

Much of the content of this entry is excerpted from his new book, PROSTATE CANCER 20/20: A Practical Guide to Understanding Management Options for Patients and Their Families

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Video trailer for Prostate Cancer 20/20

Preview of Prostate Cancer 20/20

Andrew Siegel MD Amazon author page

Prostate Cancer 20/20 on Apple iBooks

Dr. Siegel’s other books:

FINDING YOUR OWN FOUNTAIN OF YOUTH: The Essential Guide to Maximizing Health, Wellness, Fitness and Longevity

PROMISCUOUS EATING— Understanding and Ending Our Self-Destructive Relationship with Food

MALE PELVIC FITNESS: Optimizing Sexual and Urinary Health

THE KEGEL FIX: Recharging Female Pelvic, Sexual, and Urinary Health

 

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