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Page 2 of 18 Thinagaran et al. Mini-invasive Surg 2021;5:46 https://dx.doi.org/10.20517/2574-1225.2021.53

Keywords: Nerve-sparing, robotic, cystectomy, functional outcomes, continence, erection

INTRODUCTION
Over 1.72 million people worldwide live with bladder cancer (BC), half of them are from the North America
[1]
and Europe and men are affected about 4 times more than women . BC accounts for the highest lifetime
treatment cost per patient among all cancers, with the United States spending €3.6 billion and Europe
[2]
[3]
another €5 billion per year on the investigation and management of BC. Though there is a decreasing
trend in tobacco use in many parts of the world, overall population growth and increasing longevity has led
[4]
to a rise in BC incidence , which shows no signs of abating.
Muscle invasive BCs and occasionally high-grade superficial BCs are managed surgically by radical
cystectomy. This is a morbid operation with prolonged recovery time and complications that may be long
lasting in some patients. Nevertheless, radical cystectomy has evolved greatly over the years with
improvement in knowledge, skills and technology. Marshall and Whitmore provided the first detailed
[5]
description of a radical cystoprostatectomy and pelvic lymph node dissection in 1949. After Clayman
performed the first laparoscopic nephrectomy in 1991, a minimally invasive approach was promoted by
urologists for various procedures. More complicated operations like prostatectomy were also performed
laparoscopically, but minimally invasive surgery really came into its own when the da Vinci Surgical System
[6]
(Intuitive Surgical, Sunnyvale, CA) came into play . With the advent of robotic assistance in urology and
the emergence of robotic assisted radical cystectomy (RARC), allowing better dexterity and visibility, the
boundaries have been pushed and expectations have improved.

Although there are similarities in some of the basic technical aspects of nerve sparing (NS) for a radical
prostatectomy and a radical cystectomy, there are also some key differences; notwithstanding the potential
for urothelial cancer to be more lethal than prostate cancer. This makes patient selection for NS in RARC
particularly important. However, there is a reasonable body of evidence establishing the short term (≤ 5
[7,8]
years) oncologic safety of performing a NS operation for bladder cancers , which has encouraged Uro-
Oncologists to increase the application of this approach in their practice. This review aims to study the
technique of male NS RARC, review the results now available in the literature, and examine the status of
their functional outcomes and survival outcomes with longer term follow up. Before this, the neuroanatomy
of the pelvic plexus will be discussed to provide an understanding of how the technical approach to NS
during RARC has developed.

METHODS
Neuroanatomy of the pelvic plexus
The neuroanatomy of the pelvic plexus was originally described in a landmark paper by Walsh and
[9]
Donker in 1982, studying nerves that supply the penis and pelvic organs in males stillborn at birth.
Sympathetic input to pelvic plexus arises from T11-L2 and stimulates ejaculation as well as increasing the
bladder neck and urethral tone by inducing contraction of the smooth musculature. Parasympathetic input
arises from S2-4 with fibres joining the pelvic plexus and controlling bladder muscle contraction and
erectile function. Nerve fibres originating from the pelvic plexus are generally unmyelinated . Tewari
[10]
further described the surgical neuro-anatomy of the pelvic plexus, dividing it into three distinct zones, that
[11]
all may be injured during dissection, and thus cause postoperative erectile dysfunction . In broad terms the
plexus lies in the subperitoneal tissue near the pelvic ureter and its relation to the vas deferens, and extends
forward in a rectangular shape over the lateral and posterior parts of the seminal vesicles (SVs). Its three
surgically distinct zones include the proximal neurovascular plate (PNP), containing the cell bodies of the