Tridimensional Computer-Assisted Anatomic Dissection of Posterolateral Prostatic Neurovascular Bundles

Three-dimensional visualization of uterine nerve fiber distribution using fluorescence micro-optical sectioning tomography (fMOST): A pilot study

STUDY OBJECTIVE

This study aimed to observe and quantitatively analyze the morphology and distribution of uterine nerve fibers using fluorescence micro-optical sectioning tomography (fMOST). The goal was to provide an accurate morphological reference for pathological evaluations of uterine nerves.

MEASUREMENTS AND MAIN RESULTS

Using fMOST technique, we observed and analyzed the distribution of nerve fibers within the uterus. Our findings revealed a radial dispersion of nerve fibers radiating from myometrium to endometrium. The cervix uteri region exhibited a high density of nerve fibers, displaying terminations in a flower spray pattern. In contrast, nerve fibers in corpus uteri were comparatively sparse. However, we identified a unique "vine-like" pattern of a single nerve fiber extending from myometrium to endometrial layer in areas with concentrated nerves.

CONCLUSIONS

The fMOST technique is able to effectively elucidate the morphology and distribution of uterine nerve fibers. This method enables three-dimensional visualization of nerves in myometrium and offers a novel approach to observe the pathological changes in uterine nerves.

LIPUS-SCs-Exo promotes peripheral nerve regeneration in cavernous nerve crush injury-induced ED rats via PI3K/Akt/FoxO signaling pathway

OBJECTIVE

Clinical treatment of erectile dysfunction (ED) caused by cavernous nerve (CN) injury during pelvic surgery is difficult. Low-intensity pulsed ultrasound (LIPUS) can be a potential strategy for neurogenic ED (NED). However, whether Schwann cells (SCs) can respond to LIPUS stimulation signals is unclear. This study aims to elucidate the signal transmission between SCs paracrine exosome (Exo) and neurons stimulated by LIPUS, as well as to analyze the role and potential mechanisms of exosomes in CN repair after injury.

METHODS

The major pelvic ganglion (MPG) neurons and MPG/CN explants were stimulated with LIPUS of different energy intensities to explore the appropriate LIPUS energy intensity. The exosomes were isolated and purified from LIPUS-stimulated SCs (LIPUS-SCs-Exo) and non-stimulated SCs (SCs-Exo). The effects of LIPUS-SCs-Exo on neurite outgrowth, erectile function, and cavernous penis histology were identified in bilateral cavernous nerve crush injury (BCNI)-induced ED rats.

RESULTS

LIPUS-SCs-Exo group can enhance the axon elongation of MPG/CN and MPG neurons compared to SCs-Exo group in vitro. Then, the LIPUS-SCs-Exo group showed a stronger ability to promote the injured CN regeneration and SCs proliferation compared to the SCs-Exo group in vivo. Furthermore, the LIPUS-SCs-Exo group increased the Max intracavernous pressure (ICP)/mean arterial pressure (MAP), lumen to parenchyma and smooth muscle to collagen ratios compared to the SCs-Exo group in vivo. Additionally, high-throughput sequencing combined with bioinformatics analysis revealed the differential expression of 1689 miRNAs between the SCs-Exo group and the LIPUS-SCs-Exo group. After LIPUS-SCs-Exo treatment, the phosphorylated levels of Phosphatidylinositol 3-kinase (PI3K), protein kinase B (Akt) and forkhead box O (FoxO) in MPG neurons increased significantly compared to negative control (NC) and SCs-Exo groups.

CONCLUSION

Our study revealed that LIPUS stimulation could regulate the gene of MPG neurons by changing miRNAs derived from SCs-Exo, then activating the PI3K-Akt-FoxO signal pathway to enhance nerve regeneration and restore erectile function. This study had important theoretical and practical significance for improving the NED treatment.

Anatomic and functional mapping of human uterine innervation

OBJECTIVE

To better understand the physiology of pain in pelvic pain pathological conditions, such as endometriosis, in which alterations of uterine innervation have been highlighted, we performed an anatomic and functional mapping of the macro- and microinnervation of the human uterus. Our aim was to provide a 3-dimensional reconstruction model of uterine innervation.

DESIGN

This was an experimental study. We dissected the pelvises of 4 human female fetuses into serial sections, and treated them with hematoxylin and eosin staining before immunostaining.

SETTING

Academic Research Unit.

PATIENTS

None.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Detection of nerves (S100 +) and characterization of the types of nerves. The slices obtained were aligned to construct a 3-dimensional model.

RESULTS

A 3-dimensional model of uterine innervation was constructed. The nerve fibers appeared to have a centripetal path from the uterine serosa to the endometrium. Within the myometrium, innervation was dense. Endometrial innervation was sparse but present in the functional layer of the endometrium. Overall innervation was richest in the supravaginal cervix and rarer in the body of the uterus. Innervation was rich particularly laterally to the cervix next to the parametrium and paracervix. Four types of nerve fibers were identified: autonomic sympathetic (TH+), parasympathetic (VIP+), and sensitive (NPY+, CGRP1+ and VIP+). They were found in the 3 portions and the 3 layers of the uterus.

CONCLUSIONS

We constructed a 3-dimensional model of the human uterine innervation. This model could provide a solid base for studying uterine innervation in pathologic situations, in order to find new therapeutic approaches.

Different Nerve-Sparing Techniques during Radical Prostatectomy and Their Impact on Functional Outcomes

Simple Summary

Optimum preservation of potency and continence after radical prostatectomy (RP) are equally important surgical endpoints as cancer control itself. Nerve-sparing technique during RP has a major impact to both oncological and functional outcomes of the procedure and various different techniques have been developed aiming to optimize its outcomes. This literature review aims to summarize all different nerve-sparing techniques applied during RP from its first description from Patrick C. Walsh to its newer trends. The review underlines that optimum nerve-sparing expands far beyond recognising and preserving the anatomical integrity of the neurovascular bundles. It also emphasises that nerve-sparing is a field under constant development, with new technologies entering continuously the nerve-sparing field corresponding to the evolving open, laparoscopic and robotic-assisted RP approaches.

Abstract

The purpose of this narrative review is to describe the different nerve-sparing techniques applied during radical prostatectomy and document their functional impact on postoperative outcomes. We performed a PubMed search of the literature using the keywords “nerve-sparing”, “techniques”, “prostatectomy” and “outcomes”. Other potentially eligible studies were retrieved using the reference list of the included studies. Nerve-sparing techniques can be distinguished based on the fascial planes of dissection (intrafascial, interfascial or extrafascial), the direction of dissection (retrograde or antegrade), the timing of the neurovascular bundle dissection off the prostate (early vs. late release), the use of cautery, the application of traction and the number of the neurovascular bundles which are preserved. Despite this rough categorisation, many techniques have been developed which cannot be integrated in one of the categories described above. Moreover, emerging technologies have entered the nerve-sparing field, making its future even more promising. Bilateral nerve-sparing of maximal extent, athermal dissection of the neurovascular bundles with avoidance of traction and utilization of the correct planes remain the basic principles for achieving optimum functional outcomes. Given that potency and continence outcomes after radical prostatectomy are multifactorial endpoints in addition to the difficulty in their postoperative assessment and the well-documented discrepancy existing in their definition, safe conclusions about the superiority of one technique over the other cannot be easily drawn. Further studies, comparing the different nerve-sparing techniques, are necessary.

Anatomical Fundamentals and Current Surgical Knowledge of Prostate Anatomy Related to Functional and Oncological Outcomes for Robotic-Assisted Radical Prostatectomy

Context

Meticulous knowledge about the anatomy of the prostate and surrounding tissue represents a crucial and mandatory requirement during radical prostatectomy for reliable oncological and excellent replicable, functional outcomes. Since its introduction two decades ago, robotic-assisted laparoscopic radical prostatectomy (RALP) has evolved to become the predominant surgical approach in many industrialized countries.

Objective

To provide and highlight currently available literature regarding prostate anatomy and to help in improving oncological and functional outcomes in RALP.

Methods/Evidence Acquiring

PubMed database was searched using the following keywords: "robotic-assisted radical prostatectomy," "anatomy," "neurovascular bundle," "nerve," "periprostatic fascia," "pelvis," "sphincter," "urethra," "urinary incontinence," and "erectile dysfunction." Relevant articles and book chapters were critically reviewed and if eligible, they were included in this review.

Results

New evidence in regards to prostatic anatomy and surgical approaches in RALP has been reported in recent years. Besides detailed anatomical studies investigating the meticulous structure of the fascial structures surrounding the prostate and neurovascular bundle preservation, debate about the optimal RALP approach is still ongoing, inspired by recent publications presenting promising functional outcomes following modifications in surgical approaches.

Conclusions

This review provides a detailed overview of the current knowledge of prostate anatomy, its surrounding tissue, and its influence on key surgical step development for RALP.

Selection of patients for nerve sparing surgery in robot‐assisted radical prostatectomy

Context

Robot‐assisted radical prostatectomy (RARP) has become the standard surgical procedure for localized prostate‐cancer (PCa). Nerve‐sparing surgery (NSS) during RARP has been associated with improved erectile function and continence rates after surgery. However, it remains unclear what are the most appropriate indications for NSS.

Objective

The objective of this study is to systematically review the available parameters for selection of patients for NSS. The weight of different clinical variables, multiparametric magnetic‐resonance‐imaging (mpMRI) findings, and the impact of multiparametric‐nomograms in the decision‐making process on (side‐specific) NSS were assessed.

Evidence acquisition

This systematic review searched relevant databases and included studies performed from January 2000 until December 2020 and recruited a total of 15 840 PCa patients. Studies were assessed that defined criteria for (side‐specific) NSS and associated them with oncological safety and/or functional outcomes. Risk of bias assessment was performed.

Evidence synthesis

Nineteen articles were eligible for full‐text review. NSS is primarily recommended in men with adequate erectile function, and with low‐risk of extracapsular extension (ECE) on the side‐of NSS. Separate clinical and radiological variables have low accuracy for predicting ECE, whereas nomograms optimize the risk‐stratification and decision‐making process to perform or to refrain from NSS when oncological safety (organ‐confined disease, PSM rates) and functional outcomes (erectile function and continence rates) were assessed.

Conclusions

Consensus exists that patients who are at high risk of ECE should refrain from NSS. Several multiparametric preoperative nomograms were developed to predict ECE with increased accuracy compared with single clinical, pathological, or radiological variables, but controversy exists on risk thresholds and decision rules on a conservative versus a less‐conservative surgical approach. An individual clinical judgment on the possibilities of NSS set against the risks of ECE is warranted.

Patient summary

NSS is aimed at sparing the nerves responsible for erection. NSS may lead to unfavorable tumor control if the risk of capsule penetration is high. Nomograms predicting extraprostatic tumor‐growth are probably most helpful.

The male external urethral sphincter is autonomically innervated

INTRODUCTION

The aim of the present study was to describe autonomic urethral sphincter (US) innervation using specific muscular and neuronal antibody markers and 3D reconstruction.

MATERIAL AND METHODS

We performed en-bloc removal of the entire pelvis of three male human fetuses between 18 and 40 weeks. Serial whole mount sections (5 μm intervals) were stained and investigated. The sections were stained with Masson's trichrome and Eosin Hematoxylin, and immunostained with: anti-SMA antibody for smooth muscle; anti-S100 antibody for all nerves; and anti-PMP22 antibody, anti-TH antibody, anti-CGRP antibody, anti-NOS antibody for somatic, adrenergic, sensory and nitrergic nerve fibers, respectively. The slides were digitized for 3D reconstruction to improve topographical understanding. An animated reconstruction of the autonomic innervation of the US was generated.

RESULTS

The external and internal US are innervated by autonomic nerves of the inferior hypogastric plexus (IHP). These nerves are sympathetic (positive anti-TH antibody), sensory (positive anti-CGRP antibody), and nitrergic (positive anti-NOS antibody). Some autonomic fibers run within the neurovascular bundles, posterolaterally. Others run from the IHP to the posteromedial aspect of the prostate apex, above an through the rectourethral muscle. The external US is also innervated by somatic nerves (positive anti-PMP22 antibody) arising from the pudendal nerve, joining the midline but remaining below the rectourethral.

CONCLUSIONS

This study provides anatomical evidence of an autonomic component in the innervation of the external US that travels in the neurovascular bundle. During radical prostatectomy, the rectourethral muscle and the neurovascular bundles are to be preserved, particularly during apical dissection.

The application of a targeted periprostatic nerve block in transperineal template-guided prostate biopsies

Background

Our study aims to evaluate the anesthetic efficacy of multiparametric magnetic resonance imaging/transrectal ultrasound (mpMRI/TRUS) fusion-guided targeted periprostatic nerve block (PNB) for transperineal template-guided prostate biopsy (TTPB).

Methods

The patients who underwent mpMRI/TRUS fusion-guided prostate biopsy from May 2018 to March 2019 were randomized into two groups using a random number table. The intervention group (n=47) and the control group (n=45) received targeted PNB and traditional PNB, respectively. Visual analog scale (VAS) and visual numeric scale (VNS) scores were used to assess the patients' pain and quantify their satisfaction.

Results

The total detection rate for prostate cancer was 45.7%, with a comparable positive rate between the intervention group (42.6%) and the control group (48.9%), which meant there was no significant difference between the groups (P=0.542). Patient age, prostate-specific antigen, prostate volume, suspicious lesions on mpMRI, number of cores, operation time, and biopsy time were comparable between the groups. The VAS scores during biopsy were significantly lower in the intervention group than in the control group [2 (1 to 3) vs. 2 (1 to 4), P=0.019]. Conversely, the VNS scores during biopsy were higher in the intervention group [3 (2 to 4) vs. 3 (2 to 3), P=0.015]. There were no significant differences in the pain scores or the satisfaction scores at 30 min after the procedure between the two groups. There were no significant differences between the groups for complications, such as hematuria, urinary retention, infection, hemospermia, and vasovagal reaction (P>0.05).

Conclusions

Targeted PNB significantly relieved the pain and did not increase the incidence of complications for patients when compared with traditional PNB.

Effect of neurovascular bundle sparing radical cystectomy on post-operative continence and sexual function: A systematic review and meta-analysis

BACKGROUND

It is unclear whether the neurovascular bundle (NVB) sparing could improve post-operative urinary continence and potency. Furthermore, concern remains regarding the impact of nerve-sparing (NS) radical cystectomy (RC) on oncological outcomes.

OBJECTIVES

The primary objective of this meta-analysis was to evaluate whether in men undergoing NS RC could improve post-operative urinary continence and potency. The secondary objective was to assess whether NS RC could compromise the oncological control.

MATERIALS AND METHODS

A systematic search of the PubMed and Web of Science was performed in February 2020, yielding 1446 unique records. A total of 13 comparative cohort studies were included. Risk of bias in each study was assessed separately by two authors using the Newcastle-Ottawa Scale (NOS).

RESULTS

Data from 921 participants in 12 studies were synthesized in the present meta-analysis. Meta-analysis revealed that NS compared with non-nerve sparing (NNS) results in improved post-operative potency, daytime continence, and nocturnal continence. RRs were 9.35 (P < .00001) in potency, 1.11 (P = .045) in daytime continence, and 1.33 (P = .002) in nocturnal continence, respectively. Furthermore, no differences were found in the included studies reporting oncological outcomes. RRs were 0.88 (P = .61) in local and/or distant recurrence between two groups. A sensitivity analysis of prospective studies indicated consistent results.

DISCUSSION AND CONCLUSION

This meta-analysis indicates that NS RC can improve post-operative potency, and daytime and nocturnal urinary continence, without compromising oncological control, compared with NNS RC in men.

Origin and nature of pelvic ureter innervation

AIMS

Innervation of the pelvic ureter traditionally comes from the pelvic plexus. This innervation is independent: adrenergic and cholinergic. The purpose of this study was to describe more precisely the origin and nature of its innervation (adrenergic, cholinergic, nitrergic, and somatic).

METHODS

Six specimens of normal human fetal pelvis (four male and two female) from 20 to 30 weeks gestation were studied. The sections of these fetuses, carried out every 5 µm without interval, were treated with Hematoxylin Eosin (HE), with Masson's trichrome (TriM), immunolabeling of smooth muscle cells with smooth anti-actin, of nerves with anti-S100 protein, anti-tyrosine hydroxylase, anti-VAChT, anti-nNOS, and with anti- peripheral myelin protein 22 (PMP 22). The slides were scanned and two-dimensional images reconstructed in 3D, and analyzed.

RESULTS

The terminal pelvic ureter travels above and inside the inferior hypogastric plexus (IHP). The nerve fibers that innervate the ureterovesical junction come mainly from the superior hypogastric plexus (SHP) which gives off the hypogastric nerves and pelvic branches of the sacral plexus that form the IHP. Most nerve fibers meet below the ureter, behind the bladder to form an ascending bundle, which innervates the pelvic ureter. Immunohistochemical analysis shows that the nerves of the pelvic ureter consist of adrenergic, cholinergic, and nitrergic fibers.

CONCLUSION

The innervation of the distal ureter depends mainly on the SHP. This innervation is adrenergic, cholinergic, and nitrergic. It innervates the pelvic ureter in an ascending manner. This anatomical information can change rectal resection and ureteral reimplantation techniques and drug treatments for pelvic ureter stones. Neurourol. Urodynam. 36:271-279, 2017. © 2015 Wiley Periodicals, Inc.

Integration of MRI to clinical nomogram for predicting pathological stage before radical prostatectomy

BACKGROUND

Debate persists regarding whether MRI should be used routinely for preoperative evaluation of prostate cancer.

OBJECTIVE

The aim is to assess the role of prostatic magnetic resonance imaging (MRI) and other preoperative data in extra-prostatic extension (EPE) evaluation.

PATIENTS AND METHODS

From 2000 to 2013, 1743 patients operated for radical prostatectomy had a preoperative MRI. Age, clinical stage with digital rectal exam (DRE), PSA, prostate weight, biopsy, MRI and pathological findings of the surgical specimen were noticed. A multiparametric score of the variables independently associated with EPE was built with or without MRI on a random sample test population and internally validated.

RESULTS

With mean age of 62.9 years and mean PSA of 9.6 ng/ml, the population was distributed as follows: 1424 DRE T1, 254 T2, 32 T3; on biopsy 990 Gleason score = 6 and 717 ≥ 7; on MRI 1322 iT2, 290 iT3A and 131 iT3B; on prostatectomy 15 pT0, 998 pT2, 548 pT3A, 181 pT3B and 1 pT4A. In multivariate analysis, DRE, PSA, Gleason score, prostate weight and MRI were independently associated with EPE and integrated in a score with an area under curve (AUC) of 0.74 [95% CI 0.71-0.77] (0.72 without MRI, p < 0.01) a positive predictive value of 61% and a negative predictive value of 74%, internally validated. The Hosmer-Lemeshow goodness-of-fit test showed good accuracy (p = 0.77).

CONCLUSIONS

Integration of MRI with clinical data for predicting pathological stage before radical prostatectomy permits to exclude accurately EPE in 74% of cases.

[Functional results and treatment of functional dysfunctions after radical prostatectomy]

OBJECTIVE

To describe the functional results and treatment of functional dysfunctions after radical prostatectomy for localized prostate cancer.

MATERIAL AND METHOD

Bibliography search was performed from the database Medline (National Library of Medicine, Pubmed) selected according to the scientific relevance. The research was focused on continence, potency, les dyserections, couple sexuality, incontinence, treatments of postoperative incontinence, dysrection and trifecta.

RESULTS

Radical prostatectomy is an elaborate and challenging procedure when carcinological risk balances with functional results. Despite recent developments in surgical techniques, post-radical prostatectomy urinary incontinence (pRP-UI) continues to be one of the most devastating complications, which affects 9-16% of patients. Sphincter injury and bladder dysfunction are the most common causes or pRP-UI. The assessment of severity of pRP-UI that affects the choice of treatment is still not well standardized but should include at least a pad test and self-administered questionnaires. The implantation of an artificial urinary sphincter AMS800 remains the gold standard treatment for patients with moderate to severe pRP-UI. The development of less invasive techniques such as the male sling of Pro-ACT balloons has provided alternative therapeutic options for moderate and slight forms of pRP-UI. Most groups now consider the bulbo-urethral compressive sling as the treatment of choice for patients with non-severe pRP-UI. The most appropriate second-line therapeutic strategy is not clearly determined. Recent therapies such as adjustable artificial urinary sphincters and sling and stem cells injections have been investigated. Maintenance of a satisfying sex life is a major concern of a majority of men facing prostate cancer and its treatments. It is essential to assess the couple's sexuality before treating prostate cancer in order to deliver comprehensive information and consider early therapeutic solutions adapted to the couple's expectations. Active pharmacological erectile rehabilitation (intracavernous injections or phosphodiesterase type 5 inhibitors [PDE5i] on demand, during in the month following surgery) or passive (daily PDE5i after surgery) might improve the quality of erections especially in response to PDE5i. Unimpaired aspects of sexual response (orgasm) may, when the erection is not yet recovered, represent an alternative allowing the couple to preserve intimacy and complicity. Androgen blockade is a major barrier to maintain or return to a satisfying sex. Trifecta is a simple tool to present in one way the results of radical prostatectomy: in case of bilateral neurovascular preservation, Trifecta is 60% whatever the surgical approach.

CONCLUSION

Radical prostatectomy is an elaborate and challenging procedure when carcinological risk balances with functional results. Various treatments of postoperative incontinence and dysrections exist. Functional disorders after surgery have to be treated to ameliorate quality of life of patients.

A Critical Analysis of the Current Knowledge of Surgical Anatomy of the Prostate Related to Optimisation of Cancer Control and Preservation of Continence and Erection in Candidates for Radical Prostatectomy: An Update

CONTEXT

In 2010, we published a review summarising the available literature on surgical anatomy of the prostate and adjacent structures involved in cancer control and the functional outcome of prostatectomy.

OBJECTIVE

To provide an update based on new literature to help the surgeon improve oncologic and surgical outcomes of radical prostatectomy (RP).

EVIDENCE ACQUISITION

We searched the PubMed database using the keywords radical prostatectomy, anatomy, neurovascular bundle, nerve, fascia, pelvis, sphincter, urethra, urinary continence, and erectile function. Relevant articles and textbook chapters published since the last review were critically reviewed, analysed, and summarised. Moreover, we integrated aspects that were not addressed in the last review into this update.

EVIDENCE SYNTHESIS

We found new evidence for several topics. Up to 40% of the cross-sectional surface area of the urethral sphincter tissue is laterally overlapped by the dorsal vascular complex and might be injured during en bloc ligation. Denonvilliers fascia is fused with the base of the prostate in a horizontal fashion dorsally/caudally of the seminal vesicles, requiring sharp detachment when preserved. During extended pelvic lymph node dissection, the erectile nerves are at risk in the presacral and internal iliac area. Dissection planes for nerve sparing can be graded according to the amount of tissue left on the prostate as a safety margin against positive surgical margins. Vascular structures can serve as landmarks. The urethral sphincter and its length after RP are influenced by the shape of the apex. Taking this shape into account allows preservation of additional sphincter length with improved postoperative continence.

CONCLUSIONS

This update provides additional, detailed information about the surgical anatomy of the prostate and adjacent tissues involved in RP. This anatomy remains complex and widely variable. These details facilitate surgical orientation and dissection during RP and ideally should translate into improved outcomes.

PATIENT SUMMARY

Based on recent anatomic findings regarding the prostate and its surrounding tissue, the urologist can individualise the dissection during RP according to cancer and patient characteristics to improve oncologic and functional results at the same time.

Embryo Form Project: An original technique for the three-dimensional reconstruction of human embryo morphology

Our current knowledge on the developmental stages of human embryogenesis has derived from limited numbers of classical studies. Computer technology now permits accurate 3D reconstruction of embryo morphology from serial histological sections. We present a successful technique that uses either fresh or preserved serial histological sections to generate highly detailed 3D image reconstructions of very small human embryos. We present the data we obtained from the reconstruction in virtual space of previously sectioned 15 and 22.5mm embryos. Their morphologies were studied using a DICOM viewer which permitted the analysis of any specific structure in any required orientation. To our knowledge, this is the first time human embryos have been reconstructed in this way. We believe that this reconstruction technique could improve our knowledge on embryo morphogenesis, especially if coupled to the study of genes involved in embryonic development. It may also prove to be a useful pedagogical tool.

Redefining the Autonomic Nerve Distribution of the Bladder Using 3-Dimensional Image Reconstruction

PURPOSE

We sought to create a 3-dimensional reconstruction of the autonomic nervous tissue innervating the bladder using male and female cadaver histopathology.

MATERIALS AND METHODS

We obtained bladder tissue from a male and a female cadaver. Axial cross sections of the bladder were generated at 3 to 5 mm intervals and stained with S100 protein. We recorded the distance between autonomic nerves and bladder mucosa. We manually demarcated nerve tracings using ImageScope software (Aperio, Vista, California), which we imported into Blender™ graphics software to generate 3-dimensional reconstructions of autonomic nerve anatomy.

RESULTS

Mean nerve density ranged from 0.099 to 0.602 and 0.012 to 0.383 nerves per mm2 in female and male slides, respectively. The highest concentrations of autonomic innervation were located in the posterior aspect of the bladder neck in the female specimen and in the posterior region of the prostatic urethra in the male specimen. Nerve density at all levels of the proximal urethra and bladder neck was significantly higher in posterior vs anterior regions in female specimens (0.957 vs 0.169 nerves per mm2, p<0.001) and male specimens (0.509 vs 0.206 nerves per mm2, p=0.04).

CONCLUSIONS

Novel 3-dimensional reconstruction of the bladder is feasible and may help redefine our understanding of human bladder innervation. Autonomic innervation of the bladder is highly focused in the posterior aspect of the proximal urethra and bladder neck in male and female bladders.

Transanal endoscopic proctectomy and nerve injury risk: bottom to top surgical anatomy, key points

The transanal approach for rectal resection is a promising approach, because it increases the circumferential radial margin, especially for difficult cases. Meanwhile, functional sequelae are frequent after rectal cancer surgery and are often due to neurological lesions. There is little literature describing surgical anatomy from bottom to top. We combined our surgical experience with our fetal and adult anatomical research to provide a bottom-up surgical description focusing on neurological anatomy (see Video, Supplemental Digital Content 1, http://links.lww.com/DCR/A148).

Inside-out autologous vein grafts fail to restore erectile function in a rat model of cavernous nerve crush injury after nerve-sparing prostatectomy

Some autologous tissues can restore erectile function (EF) in rats after a resection of the cavernous nerve (CN). However, a cavernous nerve crush injury (CNCI) better reproduces ED occurring after a nerve-sparing radical prostatectomy (RP). The aim was to evaluate the effect on EF of an autologous vein graft after CNCI, compared with an artificial conduit. Five groups of rats were studied: those with CN exposure, exposure+vein, crush, crush+guide and crush+vein. Four weeks after surgery, the EF of rats was assessed by electrical stimulation of the CNs. The intracavernous pressure (ICP) and mean arterial pressure (MAP) were monitored during stimulations at various frequencies. The main outcome, that is, the rigidity of the erections, was defined as the ICP/MAP ratio. At 10 Hz, the ICP/MAP ratios were 41.8%, 34.7%, 20.9%, 33.9% and 20.5%, respectively. The EF was significantly lower in rats if the CNCI was treated with a vein graft instead of an artificial guide. Contrary to cases of CN resection, autologous vein grafts did not improve EF after CNCI. In terms of clinical use, the study suggests to limit an eventual use of autologous vein grafts to non-nerve-sparing RPs.

A comprehensive review of neuroanatomy of the prostate

Although oncologic efficacy is the primary goal of radical prostatectomy, preserving potency and continence is also important, given the indolent clinical course of most prostate cancers. In order to preserve and recover postoperative potency and continence after radical prostatectomy, a detailed understanding of the pelvic anatomy is necessary to recognize the optimal nerve-sparing plane and to minimize injury to the neurovascular bundles. Therefore, we reviewed the most recent findings from neuroanatomic studies of the prostate and adjacent tissues, some of which are contrary to the established consensus on pelvic anatomy. We also described the functional outcomes of radical prostatectomies following improved anatomical understanding and development of surgical techniques for preserving the neurovascular bundles.

Identification of the origin of adrenergic and cholinergic nerve fibers within the superior hypogastric plexus of the human fetus

Nerve fibers contributing to the superior hypogastric plexus (SHP) and the hypogastric nerves (HN) are currently considered to comprise an adrenergic part of the autonomic nervous system located between vertebrae (T1 and L2), with cholinergic aspects originating from the second to fourth sacral spinal segments (S2, S3 and S4). The aim of this study was to identify the origin and the nature of the nerve fibers within the SHP and the HN, especially the cholinergic fibers, using computer-assisted anatomic dissection (CAAD). Serial histological sections were performed at the level of the lumbar spine and pelvis in five human fetuses between 14 and 30 weeks of gestation. Sections were treated with histological staining [hematoxylin-eosin (HE) and Masson's trichrome (TriM)] and with immunohistochemical methods to detect nerve fibers (anti-S100), adrenergic fibers (anti-TH), cholinergic fibers (anti-VAChT) and nitrergic fibers (anti-nNOS). The sections were then digitalized using a high-resolution scanner and the 3D images were reconstructed using winsurf software. These experiments revealed the coexistence of adrenergic and cholinergic fibers within the SHP and the HNs. One-third of these cholinergic fibers were nitrergic fibers [anti-VACHT (+)/anti-NOS (+)] and potentially pro-erectile, while the others were non-nitrergic [anti-VACHT (+)/anti-NOS (-)]. We found these cholinergic fibers arose from the lumbar nerve roots. This study described the nature of the SHP nerve fibers which gives a better understanding of the urinary and sexual dysfunctions after surgical injuries.

Where does pelvic nerve injury occur during rectal surgery for cancer?

AIM

Optimal treatment of rectal adenocarcinoma involves total mesorectal excision with nerve-preserving dissection. Urinary and sexual dysfunction is still frequent following these procedures. Improved knowledge of pelvic nerve anatomy may help reduce this and define the key anatomical zones at risk.

METHOD

The MEDLINE database was searched for available literature on pelvic nerve anatomy and damage after rectal surgery using the key words 'autonomic nerve', 'pelvic nerve', 'colorectal surgery', and 'genitourinary dysfunction'. All relevant French and English publications up to May 2010 were reviewed. Reviewed data were illustrated using 3D reconstruction of the foetal pelvis.

RESULTS

The ligation of the inferior mesenteric artery and dissection of the retrorectal space can cause damage to the superior hypogastric plexus and/or hypogastric nerve. Anterolateral dissection in the 'lateral ligament' area and division of Denonvilliers' fascia can damage the inferior hypogastric plexus and efferent pathways. Perineal dissection can indirectly damage the pudendal nerve.

CONCLUSIONS

In most cases, the pelvic nerves can be preserved during rectal surgery. Complete oncological resection may require dissection close to the nerves where the tumour is located anterolaterally where it is fixed and when the pelvis is narrow.

Surgical anatomy of the prostate in the era of radical robotic prostatectomy

PURPOSE OF REVIEW

New insights in the anatomy of the prostate and the surrounding tissue evolve the technique of radical prostatectomy for the treatment of prostate cancer.

RECENT FINDINGS

Regarding the course of the erectile nerves along the prostate, recent studies confirmed the presence of parasympathetic pro-erectile nerve fibers at the anterolateral aspect of the prostate. Another study of intraoperative electrostimulation of those nerves confirmed an increase in intracavernosal pressure by stimulations between the 1 and 3 o'clock position. Therefore, it is very likely that these anterior nerve fibers have an effect on erectile function. Regarding the urethral sphincter in the male, a study showed no attachment of the external sphincter to the levator ani muscle, probably resulting in an absence of a levator ani support to the continence mechanism. The male urinary sphincter seems to be in isolation responsible for urinary continence.

SUMMARY

The nerve fibers at the anterolateral aspect of the prostate seem to participate in erectile function, which renders the concept of a high anterior release during nerve sparing beneficial. The isolated urinary sphincter mechanism results in the need to conserve as much urethral length as possible during radical prostatectomy to avoid urinary incontinence.

Neural supply to the clitoris: immunohistochemical study with three-dimensional reconstruction of cavernous nerve, spongious nerve, and dorsal clitoris nerve in human fetus

INTRODUCTION

Little detailed information is available concerning autonomic and somatic nerve supply to the clitoris, potentially causing difficulties for nerve preservation during pelvic and perineal surgery.

AIM

To identify the location and type (nitrergic, adrenergic, cholinergic and sensory) of nerve fibers in the clitoris and to provide a three-dimensional (3D) representation of their structural relationship in the human female fetus.

METHODS

Serial transverse sections were obtained from five human female fetuses (18-31 weeks of gestation) and subjected to histological and immunohistochemical investigations; digitized serial sections were used to construct a 3D representation of the pelvis.

MAIN OUTCOME MEASURES

Pelvic-perineal nerve location and type were evaluated qualitatively.

RESULTS

The female neurovascular bundle (NVB) is the anteroinferior terminal portion of the inferior hypogastric plexus that runs along the postero-lateral then lateral face of the vagina and is rich in nNOS-positive fibers. The cavernous nerve (CN) is a thin ventrocaudal collateral projection of the NVB, and this projection does not strictly follow the NVB course. The CN runs along the lateral surface of the vagina and urethra and penetrates the homolateral clitoral crus. The CN provides adrenergic, cholinergic, and nitrergic innervation to the clitoris, but not sensory innervation. The spongious nerve (SN) is the terminal and main projection of the NVB and provides nitrergic innervation to the vestibular bulbs. The dorsal clitoris nerve (DCN), somatic branche of the pudendal nerve, runs along the superior surface of the clitoral crus and body and has a segmental proerectile nitrergic activity related to communicating branches with the CN.

CONCLUSIONS

"Computer-assisted anatomic dissection" allowed the identification of the precise location and distribution of the autonomic and somatic neural supply to female erectile bodies, providing an anatomical basis for nerve-sparing surgical techniques, and participating to the understanding of neurogenic female sexual dysfunction.

Female pelvic autonomic neuroanatomy based on conventional macroscopic and computer-assisted anatomic dissections

PURPOSE

To confront nerve dissection, tissue staining, nerve immunolabelling and Computer-Assisted Anatomic Dissection (CAAD) in identifying the precise location and origin of intrapelvic autonomic nerve fibers and to provide a three-dimensional (3D) representation of their relationship to other anatomical structures.

METHODS

Serial transverse sections of the pelvic portion of five human female fetuses (18-31 weeks of gestation) were studied histologically (with hematoxylin/eosin and Masson trichrome) and immunohistochemically (anti-protein S100 antibody) digitized and reconstructed three-dimensionally with Surf driver software for Windows (Winsurf 4.3). Three fresh female adult cadavers were macroscopically dissected to individualize the inferior hypogastric plexus afferences and efferences and their anatomical relationships.

RESULTS

This combined investigation including the CAAD technique allowed identifying the precise location and distribution of the pelvic nerve elements and their relationships to female pelvic organs. Hypogastric nerves (HN) were located in the retrorectal multilaminar structure and joined the homolateral inferior hypogastric plexus (IHP) at the lateral border of the recto-uterine pouch. The intersection of the ureter with the posterior wall of the uterine artery precisely located the junction of HN and IHP. Antero-inferior branches supplying female sexual and continence organs originated from the antero-inferior angle of IHP and were bundled at the posterolateral vaginal wall.

CONCLUSIONS

CAAD is an encouraging anatomical method for the development of anatomical and surgical research and teaching. Complementary to traditional anatomical studies, it may provide useful anatomical data for the comprehension of postoperative sexual and urinary dysfunction and the development of nerve-sparing surgical techniques.