Pelvic Splanchnic Nerves Research Articles

Cadaveric study of nerves supplying the membranous urethra

To better understand the anatomy of the region of the male membranous urethra in order to preserve continence during radical cystectomy and prostatectomy. Cadaveric dissections of 15 male specimens were undertaken to investigate the nerves to membranous urethra. The nerves were traced from both an intrapelvic approach and a perineal approach. The origin, course, and distribution of the branches to the membranous urethra region were investigated in detail. The membranous urethra is innervated by branches of inferior hypogastric plexus (IHP) and intrapelvic and extrapelvic branches of pudendal nerve (PN). The pelvic nerve from IHP originated from the caudal most root of the pelvic splanchnic nerve, running along the surface of the levator ani muscle (LAM) to enter the membranous urethra at the 5 and 7 O'clock positions. In 40% of specimens we found that the intrapelvic branches were supplied by the PN. Before exiting the pudendal canal, PN gives off an intrapelvic branch that traverses the LAM to course with the pelvic nerve and innervate the membranous urethra; the distance between these intrapelvic branches and prostatic apex is 5.3 +/- 1.8 mm. The branches originating from the dorsal nerve of penis innervate the membranous urethra in 53.3% of specimens; these nerve branches are located 4.2 +/- 1.1 mm from the prostatic apex. Dissection of the seminal vesicles and the prostatic apex during radical cystectomy and prostatectomy likely injures the nerve responsible for continence.

Coexistence of adrenergic and cholinergic nerves in the inferior hypogastric plexus: anatomical and immunohistochemical study with 3D reconstruction in human male fetus

Classic anatomical methods have failed to determine the precise location, origin and nature of nerve fibres in the inferior hypogastric plexus (IHP). The purpose of this study was to identify the location and nature (adrenergic and/or cholinergic) of IHP nerve fibres and to provide a three-dimensional (3D) representation of pelvic nerves and their relationship to other anatomical structures. Serial transverse sections of the pelvic portion of two human male fetuses (16 and 17 weeks' gestation) were studied histologically and immunohistochemically, digitized and reconstructed three-dimensionally. 3D reconstruction allowed a 'computer-assisted dissection', identifying the precise location and distribution of the pelvic nerve elements. Proximal (supra-levator) and distal (infra-levator) communications between the pudendal nerve and IHP were observed. By determining the nature of the nerve fibres using immunostaining, we were able to demonstrate that the hypogastric nerves and pelvic splanchnic nerves, which are classically considered purely sympathetic and parasympathetic, respectively, contain both adrenergic and cholinergic nerve fibres. The pelvic autonomic nervous system is more complex than previously thought, as adrenergic and cholinergic fibres were found to co-exist in both 'sympathetic' and 'parasympathetic' nerves. This study is the first step to a 3D cartography of neurotransmitter distribution which could help in the selection of molecules to be used in the treatment of incontinence, erectile dysfunction and ejaculatory disorders.

Laparoscopic Feasibility of Nerve-Sparing Radical Hystrectomy and Trachelectomy in Patients with Cervical Cancer: Preliminary Results and Efforts To Increase Radicality

The aim of this study was to describe a technique for preserving the autonomic nerves including hypogastric nerves, pelvic splanchnic nerves, pelvic plexus and its vesical branches during type III laparoscopic radical hystrectomy(LRH) and trachelctomy(LRT) and to evaluate postoperative bladder function in these patients. Nerve-sparing LRH and LRT were performed in consecutive 11 patients with early stage cervical cancer from 2006 to 2008. Bilateral hypogastric nerves and vesical branches of pelvic splanchnic nerves were preserved in 4 cases in both sides and 7 cases in only left side.

Causes of Fecal and Urinary Incontinence After Total Mesorectal Excision for Rectal Cancer Based on Cadaveric Surgery: A Study From the Cooperative Clinical Investigators of the Dutch Total Mesorectal Excision Trial

Total mesorectal excision (TME) for rectal cancer may result in anorectal and urogenital dysfunction. We aimed to study possible nerve disruption during TME and its consequences for functional outcome. Because the levator ani muscle plays an important role in both urinary and fecal continence, an explanation could be peroperative damage of the nerve supply to the levator ani muscle. TME was performed on cadaver pelves. Subsequently, the anatomy of the pelvic floor innervation and its relation to the pelvic autonomic innervation and the mesorectum were studied. Additionally, data from the Dutch TME trial were analyzed to relate anorectal and urinary dysfunction to possible nerve damage during TME procedure. Cadaver TME surgery demonstrated that, especially in low tumors, the pelvic floor innervation can be damaged. Furthermore, the origin of the levator ani nerve was located in close proximity of the origin of the pelvic splanchnic nerves. Analysis of the TME trial data showed that newly developed urinary and fecal incontinence was present in 33.7% and 38.8% of patients, respectively. Both types of incontinence were significantly associated with each other (P = .027). Low anastomosis was significantly associated with urinary incontinence (P = .049). One third of the patients with newly developed urinary and fecal incontinence also reported difficulty in bladder emptying, for which excessive perioperative blood loss was a significant risk factor. Perioperative damage to the pelvic floor innervation could contribute to fecal and urinary incontinence after TME, especially in case of a low anastomosis or damage to the pelvic splanchnic nerves.

Understanding the planes of total mesorectal excision through surgical anatomy of pelvic fascia

To study the relationship of mesorectum with fasciae and nerves in the pelvic cavity and to specify the proper planes of dissection in total mesorectal excision. Twenty-four pelvises (12 males and 12 females) harvested from cadavers were studied by dissection. There were three planes surrounding the rectum as the visceral fascia, vesicohypogastric fascia and parietal fascia. The pelvic plexus and its branches situated between the visceral fascia and the vesicohypogastric fascia. Pelvic splanchnic nerves and hypogastric nerves were observed between the visceral fascia and the parietal fascia. The posterior plane of total mesorectal excision lies between the visceral fascia and the parietal fascia. The lateral dissection should be conducted in a plane between the visceral fascia and the vesicohypogastric fascia. The proper planes for posterior and lateral resection can be identified by the hypogastric nerve and the pelvic plexus respectively.

Development of the human hypogastric nerve sheath with special reference to the topohistology between the nerve sheath and other prevertebral fascial structures

Semi-serial sections from the lumbosacral region of nine fetuses (8-25 weeks gestation) were examined to clarify the lumbar prevertebral fascial arrangement. The prevertebral fasciae became evident after 12 weeks of age. After 20 weeks of age, the hypogastric nerve (HGN) was sandwiched by two fascial structures; the ventral fascia which seemed to correspond to the mesorectal fascia, whereas the dorsal fascia corresponded to the presacral fascia. These fasciae or the HGN sheaths extended laterally along the ventral aspects of the great vessels and associated lymph follicles. The ventral fascia is, to some extent, fused with the mesocolon descendens on the left side of the body. Notably, the lateral continuation of these two fasciae also sandwiches the left ureter, but not the right ureter, presumably due to modifications by the left-sided fusion fascia. A hypothetical common sheath for the HGN and ureter (i.e., the ureterohypogastric or vesicohypogastric fascia) might thus be an oversimplification. Before retroperitoneal fixation, the morphology of the peritoneal recess along the mesocolon descendens and mesosigmoid suggested interindividual differences in location, shape, and size. Therefore, in adults the ease of surgical separation of the rectum and left-sided colon from the HGN seems to depend on interindividual differences in the development of the embryonic peritoneal recess. On the caudal side of the second sacral segment, fascial structures were restricted along and around the HGN, pelvic splanchnic nerve, and pelvic plexus. The rectal lateral ligament thus seems to represent a kind of migration fascia formed by mechanical stress.

Anatomy of the Sacral Roots and the Pelvic Splanchnic Nerves in Women Using the LANN Technique

To report on our anatomic and electrophysiologic findings about the sacral nerve roots and the pelvic splanchnic nerves during laparoscopic pelvic surgery. The pelvic splanchnic nerves and the sacral nerve roots were dissected in 336 consecutive patients undergoing laparoscopy for pelvic pain syndrome or gynecologic diseases. Intraoperative assessment of the functionality of the exposed nerves was performed using the LAparoscopic Neuro-Navigation (LANN) technique. Dissection of the sacral roots and the splanchnic pelvic nerves lateral to the sacral hypogastric fascia was feasible without any complications in all patients in this series. The mean surgical time was 16 minutes per side. The pelvic splanchnic nerves could be divided anatomically and functionally into vesical and rectal nerve fibers. Laparoscopy in combination with the LANN technique not only permits an intraoperative functional mapping of the pelvic motoric autonomous nerves but also a differentiation between the vesical and rectal nerves and between the efferent and afferent pelvic nerves.

Nerve preservation in tension-free vaginal mesh procedures for pelvic organ prolapse: a cadaveric study using fresh and fixed cadavers

The aims of this study were, using fixed and fresh cadavers, to clarify how closely the pelvic splanchnic nerve, levator ani nerve (LAN), and sacrospinous ligament (SSL) are located and to examine how to avoid nerve injury during the posterior tension-free vaginal mesh procedure (TVMP), in which mesh is applied through the SSL. Macroscopic dissection of fixed cadavers demonstrated that the LAN crossed the inside of the SSL at a point 0-18 mm medial to the ischial spine and entered the muscle at a point 12-26 mm inferior to the ischial spine and 40-55 mm anterolateral to the coccyx. Dissection after TVMP of fresh cadavers revealed that the point of penetration of mesh through the SSL was close to the LAN. To preserve the LAN, penetration of the SSL should be within 5 mm of the lower margin at a point 20-25 mm medial to the ischial spine.

Anatomic identification and functional outcomes of the nerve sparing Okabayashi radical hysterectomy

Objectives. To clarify the anatomy necessary for the nerve sparing Okabayashi's radical hysterectomy, we meticulously separated the blood vessels and connective tissues to preserve the pelvic splanchnic nerve, the hypogastric nerve, and the bladder branch of the inferior hypogastric plexus under magnification (× 2.5) during the Okabayashi radical hysterectomy. Methods. Twenty-four patients (FIGO stage IB, n = 22, and stage IIA, n = 2) underwent meticulous nerve sparing radical hysterectomy during 2004 to 2006. Postoperative assessment of bladder function consisted of the time to (a) achieve a postvoid residual urine volume (PVR) less than 50 ml, (b) obtain a sensation of bladder fullness, and (c) obtain satisfaction of micturition. Results. Isolation of the deep uterine vein could preserve one of the branches of the pelvic splanchnic nerve. The hypogastric nerve in the lateral rectal wall was isolated to the inferior hypogastric plexus. During the division of the posterior leaf of the vesicouterine ligament (VUL), isolation of the inferior vesical vein could reveal the bladder branch from the inferior hypogastric plexus. Only the uterine branch from the inferior hypogastric plexus was isolated and divided. Then, the T-shaped nerve plane consisting of the hypogastric nerve, the pelvic splanchnic nerve and the bladder branch from the inferior hypogastric plexus is preserved. Urinary functions: (a) 11 out of 24 patients had measured PVR of less than 50 ml by postoperative day (POD) 14 and all patients had achieved this by day 21 (mean POD: 14.64 ± 2.04). (b) Twenty-two out of 24 patients reported a sensation of bladder fullness by POD 14 and all by POD 21 (mean POD: 11.25 ± 1.78). (c) Seventeen out of 24 patients reported satisfaction of micturition by POD 14 and all by POD 21 (mean POD: 12.34 ± 2.32). Conclusion. In order to accomplish the nerve sparing Okabayashi's radical hysterectomy, it is necessary to meticulously divide the posterior leaf of the vesicouterine ligament. By the separation of the inferior vesical vein in the posterior leaf of the vesicouterine ligament, the bladder branch from the inferior hypogastric plexus can be identified and preserved. All patients recovered their urinary function completely by POD 21.

Reconstruction of cavernous nerves by nerve grafts to restore potency: contemporary review of technical principles and basic anatomy

The review discusses the efficacy of reconstructing the neurovascular bundle to regain sexual function if nerve-sparing prostatectomy is unfeasible. Eleven studies could be found describing the reconstruction of neurovascular bundles. All reconstructive procedures displayed technical inadequacies. The effectiveness of unilateral neurovascular bundle reconstruction remains statistically insignificant when compared with procedures without reconstruction. The efficacy of reconstructing both neurovascular bundles ranges between 0 and 43%. Concerning basic anatomy, the neurovascular bundle contains fibers innervating the cavernous nerves, prostate, rectum, and levator ani muscle. The terms cavernous nerve and neurovascular bundle have often been wrongly considered synonymous. The pelvic splanchnic nerves probably do not join the neurovascular bundle proximal to the bladder/prostate junction but rather at variable distances from 10 to 20 mm distal to it. Therefore, described proximal coaptation sites at the bladder/prostate junction possibly encompass only the hypogastric nerve. Modest clinical results are partly due to inadequate surgical techniques and are mainly due to the anatomical and topographical complexity of the cavernous nerves. Contemporary nerve grafting techniques probably do not allow for the regeneration of all cavernous nerves.

Human pelvic extramural ganglion cells: a semiquantitative and immunohistochemical study

In pelvic surgery, much attention is paid to nerve bundles but not to ganglion cells. Using serial section histology of 14 postmortem-treated hemipelvis (eight males, six females; mean, 79 years old), we examined the population number, distribution, and tyrosine hydroxylase-immunoreactivity (TH-IR; suggesting sympathetic neurons) of extramural pelvic ganglion cells. All pelvic ganglion cells were uniformly sized (25-30 microm) contrasting with small intramural rectal neurons. Abundant ganglion cells (30,000-140,000 unilaterally) existed not only along the pelvic viscera except for the rectum, but also along the hypogastric nerve, pelvic splanchnic nerve, pelvic plexus, and associated branches excluding those within the mesorectum. The intrapelvic ganglion cells outside the sympathetic trunk did not form macroscopically identifiable ganglia, but made small clusters (0.1-2.0 mm of maximum diameter) or were diffusely scattered within nerve bundles. More than half of these cells appeared TH-IR positive, although the positive/negative proportion differed between nerves and specimens. Greater numbers of ganglion cells were found in dorsosuperior sites (e.g., around the seminal vesicle) rather than in ventroinferior sites (e.g., along the urethra) in males, and vice versa in females. However, in total cell numbers, interindividual variations were evident rather than intergender difference. Due to significant interindividual variations in cell number, differences are likely to exist between patients in "resistance" to surgical stresses. We hypothesized that pelvic ganglion cells are liable to be damaged due to drying along the surgical margin, hypoxia in venous bleeding, pressure from surgical retractors, extension stress with taping and excess traction and/or direct injury with electrical scalpels.

Craniosacral Outflow: Cranial Nerve X and the Pelvic Splanchnic Nerves of the Parasympathetic Division of the ANS.

The vagus nerve (CN X) and three pelvic splanchnic nerves (S1, S2, S3) carry parasympathetic fibers to the infracranial portion of the body, where their preganglionic fibers synapse in diffuse ganglia present in the substance of the target viscus. Although its nucleus resides in the caudal brainstem, the vagus nerve does not supply structures in the head. Rather, it is a vagabond, supplying a host of tissues and organs in the thorax and abdomen. In the thorax, the vagus supplies the upper GI tract (for secretion and smooth muscle control), the heart, and respiratory airways. In the abdomen, the nerve innervates the gastrointestinal tract approximately to the left colic (splenic) flexure, other viscera derived from the gut tube, and kidneys. The remainder of the GI tract (descending colon, sigmoid colon, and rectum) and the urogenital structures (bladder and erectile bodies) are provided preganglionic parasympathetic innervation via the three pelvic splanchnic nerves. These arise from the lateral horn of spinal cord levels S2, S3 (largest contributor), and S4. A number of important clinical and surgical considerations derive from this anatomy.

Sexual problems in male patients older than 20 years with anorectal malformations

Background/Purpose The nervi erigentes in high- and intermediate-type male anorectal malformation (ARM) runs a relatively medial course and is vulnerable in sacro-perineal dissection. These types of ARM are also associated with a high frequency of sacral anomaly, and sexual problems may be expected. However, sexual function cannot be evaluated until after the individual passes puberty. Few reports have investigated the sexual status of pubescent males with ARM. The present study evaluated sexual problems in patients with high- and intermediate-type ARM. Methods Sexual problems such as erectile dysfunction and ejaculatory incompetence were evaluated in 17 of 23 men aged more than 20 years who underwent operation for high- or intermediate-type ARM between September 1974 and January 2005. Results Erection angle was normal in 9 patients (52.9%), mild in 6 patients (35.3%), and dysfunctional in 2 patients (11.8%). Ejaculatory function was normal in 10 patients (58.8%), with ejaculatory incompetence in 5 patients (29.4%) and retrograde ejaculation in 2 patients (11.8%). Either erectile or ejaculatory dysfunction was present in 5 patients (29.4%), whereas both were present in 2 patients (11.8%). Sexual problems were identified in 7 patients (41.2%), with sacral anomalies in 5 (71.4%) of these 7 patients. Conclusions Sexual problems such as erectile and ejaculatory dysfunction are common in patients with high- or intermediate-type ARM. Patients with sexual distress require persistent follow-up and continuous counselling to support their sexual problems.

Precise Anatomical Location of the Autonomous Nerve from the Pelvic Plexus to the Corpus Cavernosum

Purpose: We wanted to study the precise anatomical location of the branches of the pelvic plexus from the sacral root to the cavernous nerve. Materials and Methods: We performed microdissection on the pelvises from 4 male formalin fixed cadavers under a Zeiss surgical microscope and we traced the location of the branches of the pelvic plexus at a magnification of 6x. Results: The configuration of the pelvic plexus was an irregular diamond shape rather than rectangular. It was located retroperitoneally on the lateral wall of the rectum 8.2 to 11.5cm from the anal verge. Its midpoint was located 2.0 to 2.5cm from the seminal vesicle posterosuperiorly. A prominent neurovascular bundle (NVB) was located on the posterolateral portion of the apex and the mid portion of the prostate. The pelvic splanchnic nerve (PSN) joined the NVB at a point distal and inferior to the bladder-prostate (BP) junction. The PSN components joined the NVB in a spray-like distribution at multiple levels distal to the BP junction. The distance from the membranous urethra to the NVB was 0.5 to 1.2cm. We also found multiple tiny branches on the anterolateral aspect of the prostate apex. Conclusions: In contrast to the usual concept, the NVB was much wider above the mid portion of the prostrate and it supplied multiple tiny branches on the anterolateral aspect of the prostate. The PSN branches arose from the more posteroinferior area of the pelvic plexus. Therefore, we recommend a more anterior dissection of the lateral pelvic fascia for nerve sparing radical prostatectomy. If surgeons plan a nerve graft after radical prostatectomy, they should consider this neuroanatomy for obtaining a successful outcome. (Korean J Urol 2006;47:876-881) ꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏ

The LANN Technique to Reduce Postoperative Functional Morbidity in Laparoscopic Radical Pelvic Surgery

We investigated the feasibility and advantages of introducing Laparoscopic Neuro-Navigation (LANN) into the field of laparoscopic gynecologic radical pelvic surgery. In a prospective pilot study, 261 consecutive patients underwent laparoscopic radical pelvic surgery for cervical cancer or deep infiltrating endometriosis of the parametria. During the procedure, dissection and electrostimulation, and consequently, sparing of the pelvic parasympathetic nerves by transection of the parametria, were performed. Postoperative bladder dysfunction was documented. Laparoscopic dissection and electrostimulation of the pelvic splanchnic nerves were feasible in all patients without any complications, and the rate of postoperative bladder dysfunction was considerably reduced, to less than 1% of the patients. The parasympathetic nerve-sparing method using the Laparoscopic Neuro-Navigation technique in laparoscopic radical pelvic gynecologic surgery is a feasible and reproducible technique that preserves postoperative bladder function.

Intraoperative electrical stimulation of the pelvic splanchnic nerves during nerve-sparing radical hysterectomy

Objectives. This study sought to determine whether intraoperative electrical stimulation (IES) of pelvic splanchnic nerves (PSNs) while monitoring bladder contraction was useful to predict postoperative bladder function during conventional nerve-sparing radical hysterectomy. Methods. Seventeen patients with stage Ib or IIa cervical cancer underwent conventional radical hysterectomy. IES was performed in all cases, stimulating the roots of PSN, the posterior sheath of the vesicouterine ligament (PVL) and the dorsal area of the ligament. After resection of the uterus, the PSN roots were stimulated again. Bladder function was evaluated by urodynamic study (UDS) preoperatively and 3 months after surgery. Results. The results of IES were consistent with bladder function evaluated by postoperative UDS. In 13 of 17 cases, an increased intravesical pressure was observed with IES of the PSN roots after uterus resection. Nine of 13 cases showed marked detrusor contraction with UDS 3 months after surgery and were able to void without using abdominal pressure except in one case. In the remaining 4 of 17 cases, no response could be detected to IES on either side. Three cases voided using abdominal pressure and one used clean intermittent self-catheterization without spontaneous voiding. Conclusions. IES while monitoring intravesical pressure during radical hysterectomy represents a technically simple and useful procedure for the prediction of postoperative bladder function.

A systematic nerve-sparing radical hysterectomy technique in invasive cervical cancer for preserving postsurgical bladder function

The objective of this study is to describe a technique for preserving the autonomic nerve systematically, including the hypogastric nerves, pelvic splanchnic nerves, and pelvic plexus and its vesical branches, based on anatomic considerations for the autonomic nerves innervating the urinary bladder, in radical hysterectomies and to assess postsurgical bladder function. A nerve-sparing radical hysterectomy was carried out on 27 consecutive patients with uterine cervical cancer treated between 2000 and 2002. The FIGO stages of the disease consisted of 10 stage Ib1, 6 stage Ib2, 3 stage IIa, and 8 stage IIb. The nerve-sparing procedure was successfully completed in 22 of the 27 patients (81.5%) in the study. At 1 year after the operation, bladder symptoms were significantly improved in the nerve-sparing group compared to the non-nerve-sparing group. Urinary incontinence and abnormal (diminished) bladder sensation were observed in three of the five patients (two patients had both symptoms), for whom the nerve-sparing procedure could not be performed, but none of the 22 patients for whom the nerve-sparing procedure was performed had incontinence, and only two patients had abnormal (increased) bladder sensation (P= 0.0034 for incontinence and P= 0.030 for abnormal bladder sensation). The patients' survival was not adversely affected by the nerve-sparing procedure. Although it is still preliminary, the surgical technique described in this report is thought to be effective for preserving bladder function, and thus, the quality of life could be improved for patients with cervical cancer who are treated with a radical hysterectomy. For further evaluation of the efficacy of nerve-sparing radical hysterectomy, a prospective randomized trial needs to be performed.

Gerard W. Ostheimer “What’s New in Obstetric Anesthesia” Lecture

Gerard W. Ostheimer “What’s New in Obstetric Anesthesia” Lecture

A systematic nerve-sparing radical hysterectomy technique in invasive cervical cancer for preserving postsurgical bladder function

The objective of this study is to describe a technique for preserving the autonomic nerve systematically, including the hypogastric nerves, pelvic splanchnic nerves, and pelvic plexus and its vesical branches, based on anatomic considerations for the autonomic nerves innervating the urinary bladder, in radical hysterectomies and to assess postsurgical bladder function. A nerve-sparing radical hysterectomy was carried out on 27 consecutive patients with uterine cervical cancer treated between 2000 and 2002. The FIGO stages of the disease consisted of 10 stage Ib1, 6 stage Ib2, 3 stage IIa, and 8 stage IIb. The nerve-sparing procedure was successfully completed in 22 of the 27 patients (81.5%) in the study. At 1 year after the operation, bladder symptoms were significantly improved in the nerve-sparing group compared to the non–nerve-sparing group. Urinary incontinence and abnormal (diminished) bladder sensation were observed in three of the five patients (two patients had both symptoms), for whom the nerve-sparing procedure could not be performed, but none of the 22 patients for whom the nerve-sparing procedure was performed had incontinence, and only two patients had abnormal (increased) bladder sensation (P= 0.0034 for incontinence andP= 0.030 for abnormal bladder sensation). The patients' survival was not adversely affected by the nerve-sparing procedure. Although it is still preliminary, the surgical technique described in this report is thought to be effective for preserving bladder function, and thus, the quality of life could be improved for patients with cervical cancer who are treated with a radical hysterectomy. For further evaluation of the efficacy of nerve-sparing radical hysterectomy, a prospective randomized trial needs to be performed.

ANATOMICAL ANALYSIS OF THE NEUROVASCULAR BUNDLE SUPPLYING PENILE CAVERNOUS TISSUE TO ENSURE A RELIABLE NERVE GRAFT AFTER RADICAL PROSTATECTOMY

Urologists and anatomists have disagreed concerning pelvic neurovascular bundle (NVB) structure. Recently interposition nerve grafting has been performed to improve erectile function after radical prostatectomy. To refine this procedure we reviewed NVB structure from the surgical viewpoint. Seven fresh cadavers and serial horizontal sections from 20 formalin fixed cadavers were used for gross dissection and histological examination. Fresh cadaver dissections demonstrated that the pelvic splanchnic nerve (PSN) joined the NVB at a point distal or inferior to the bladder-prostate (BP) junction. Histologically hypogastric nerve fibers were much more dominant than PSN fibers at the BP junction, and the NVB, covered by the lateral pelvic fascia, became evident at levels more than 20 to 30 mm below the BP junction. PSN components joined the NVB in a spray-like distribution at multiple levels more than 20 mm distal to the BP junction. At these low levels nerves tended to be located outside of the NVB at the dorsolateral margin of the prostate. The cranial end of the mimic interposition nerve graft was directed toward the hypogastric nerve rather than the PSN. In contrast to general clinical opinion, the NVB appears to supply few PSN components at the BP junction with caudal PSN branches reaching the dorsolateral prostate more than 20 mm below the BP junction. This anatomy has important implications for a reliable nerve graft.