Systematization of the vesical and uterovaginal efferences of the female inferior hypogastric plexus (pelvic): applications to pelvic surgery on women patients

Objective To locate and describe the various efferences of the plexus in order to make it easier to avoid nerve lesions during pelvic surgery on women patients through a better anatomical knowledge of the inferior hypogastric plexus (IHP). Materials and methods We dissected 27 formalin embalmed female anatomical subjects, none of which bore any stigmata of subumbilical surgery. The dissection was always performed using the same technique: identification of the inferior hypogastric plexus, whose posterior superior angle follows on from the hypogastric nerve and whose top, which is anterior and inferior, is located exactly at the ureter’s point of entry into the base of the parametrium, underneath the posterior layer of the broad ligament. Results The IHP is located at the level of the posterior floor of the pelvis, opposite to the sacral concavity. Its top, which is anterior inferior, is at the point of contact with the ureter at its entry into the posterior layer of the broad ligament. The uterovaginal, vesical and rectal efferences originate in the paracervix. Three efferent nerves branch, two of them from its top and the third from its inferior edge: (1) A vaginal nerve, medial to the ureter, follows the uterine artery and divides into two groups: anterior thin, heading for the vagina and the uterus; posterior, voluminous, heading in a superior rectal direction (=superior rectal nerve). (2) A vesical nerve, lateral to the ureter, divides into two groups, lateral and medial. (3) The inferior rectal nerve emerges from the inferior edge of the IHP, between the fourth sacral root and the ureter’s point of entry into the base of the parametrium. Conclusion The ureter is the crucial point of reference for the IHP and its efferences and acts as a real guide for identifying the anterior inferior angle or top of the IHP, the origin of the vaginal nerve, the level of the ureterovesical junction and the division of the vesical nerve into its two medial and lateral branches. Dissecting underneath and inside the ureter and the uterine artery involves a risk of lesion of the vaginal nerve and its uterovaginal branches. Further forward, between the intersection and the ureterovesical junction, dissecting and/or coagulating under the ureter involves a risk of lesions to the vesical nerve, which are likely to explain the phenomena of denervation of the anterior floor encountered after certain hysterectomies and/or surgical treatments of vesicoureteral reflux.     

直肠癌手术相关腹膜后自主神经的筋膜解剖学观察

目的　从临床解剖学和组织学角度进一步阐明盆自主神经的筋膜层次。 方法　选取7具尸体标本和52例接受腹腔镜直肠癌切除手术的病人,观察其自主神经与肾前筋膜-骶前筋膜的关系。切取尸体降乙结肠系膜与主髂动脉之间、直肠系膜与骶骨骨膜之间的腹膜后组织做组织学检查。 结果　解剖学观察显示,腹主动脉丛、上腹下丛、腹下神经、下腹下丛位于肾前筋膜-骶前筋膜后外侧。组织学检查显示：神经纤维位于筋膜后,部分较细的纤维位于筋膜内。 结论　自主神经位于肾前筋膜-骶前筋膜后外侧。保持这一筋膜的完整性,是直肠癌手术中保护自主神经的解剖学基础和基本方法。     

肠系膜下动脉根部自主神经保护的解剖学基础

目的　观察肠系膜下动脉（IMA）根部与其周围自主神经的解剖学关系,为肠系膜下动脉根部自主神经保护提供解剖学证据。 方法　7例10%福尔马林固定标本进行大体解剖及显微解剖;2例新鲜标本模拟腹腔镜下直肠癌D3根治术中肠系膜下动脉根部自主神经的显露和保护。 结果　上腹下丛(SHP)的左、右侧束及束间交通支与肠系膜下动脉根部关系密切。右侧束距离肠系膜下动脉根部较远,位于肾前筋膜下。以左侧束降支为界,其近端,上腹下丛左侧束、肠系膜下丛、腹主动脉丛紧贴肠系膜下动脉根部左侧壁并相互延续,其远端左侧束走行于肾前筋膜下。左侧束降支距离IMA起点的距离不恒定。 结论　在肾前筋膜前平面分离可有效保护上腹下丛右侧束及侧束间交通支;以SHP左侧束降支作为肠系膜下动脉根部离断的解剖学标志可以有效保护左侧束。     

The female inferior hypogastric (= pelvic) plexus: anatomical and radiological description of the plexus and its afferences—applications to pelvic surgery

AIM OF THE STUDY: We wanted to determine the anatomical features of the inferior hypogastric plexus (IHP), and the useful landmarks for a safe surgical approach during pelvic surgery. MATERIALS AND METHODS: We dissected the IHP in 22 formolized female anatomical subjects, none of which bore any stigmata of subumbilical surgery. RESULTS: The inferior hypogastric plexus (IHP) is a triangle with a posterior base and an anterior inferior top. It can be described as having three edges and three angles; its inferior edge stretches constantly from the fourth sacral root to the ureter's point of entry into the posterior layer of the broad ligament; its cranial edge is strictly parallel to the posterior edge of the hypogastric artery, along which it runs at a distance of 10 mm; its posterior (dorsal) edge is at the point of contact with the sacral roots, from which it receives its afferences. They most frequently originate from S3 or S4 (60%) and then, in one or two branches, often from S2 (40%), never from S1 and in exceptional cases from S5 (20%). There are sympathetic afferences in 30% of cases, usually through a single branch of the second, third or fourth sacral ganglion. All IHPs have at least one sacral afference and sometimes there may be up to three afferences from the same sacral root. Its dorsal cranial angle, which is superior, comes after the SHP (hypogastric nerve or presacral nerve filament); its anterior inferior angle is located exactly at the ureter's point of entry into the posterior layer of the broad ligament. This is the top of the IHP; its posterior inferior angle is located at the point of contact with the fourth sacral root. At its entrance at the base of the parametrium the pelvic ureter is the anterior, fundamental positional reference for the IHP. The vaginal efferences come out of the top of the IHP through branches leading to the bladder, the vagina and the rectum, which originate through two trunks exactly underneath the crossing point of the ureter and the uterine artery: (i) one trunk leading to the bladder runs along and underneath the ureter and divides into two groups, which are lateral and medial, trigonal. (ii) the trunk leading to the vagina runs along the inferior edge of the uterine artery. At the point of contact with the lateral edge of the vagina, it splits into two groups: anterior thin and posterior voluminous. Some of its branches perforate the posterior wall of the vagina and are distributed to the rectovaginal septum in a tooth comb pattern. The inferior branches, which emerge from the inferior edge of the IHP, reach the rectum directly. The dissection of the 22 specimens allowed us to describe three efferent plexuses: a vaginal rectal plexus, a vesical plexus and a inferior rectal plexus. So the IHP's anterior, fundamental positional reference is the pelvic ureter at the point where it enters at the base of the parametrium, then at the crossing point of the uterine artery. The ureter is the vector for vesical efferences, the uterine artery is the vector for vaginal efferences, which are thus sent into the vesicovaginal septum and the rectovaginal septum. This surgical point of reference is of vital importance in nerve sparing during the course of a simple or extended hysterectomy. Any dissection carried out underneath and outside of the ureter inevitably carries a risk of lesions to its efferent, lateral vesical or medial, rectovaginal fibres.     

Smooth muscle of the male pelvic floor: An anatomic study

Knowledge of the anatomy of the male pelvic floor is important to avoid damaging the pelvic floor muscles during surgery. We set out to explore the structure and innervation of the smooth muscle (SM) of the whole pelvic floor using male fetuses. We removed en-bloc the entire pelvis of three male fetuses. The specimens were serially sectioned before being stained with Masson's trichrome and hematoxylin and eosin, and immunostained for SMs, and somatic, adrenergic, sensory and nitrergic nerve fibers. Slides were digitized for three-dimensional reconstruction. We individualized a middle compartment that contains SM cells. This compartment is in close relation with the levator ani muscle (LAM), rectum, and urethra. We describe a posterior part of the middle compartment posterior to the rectal wall and an anterior part anterior to the rectal wall. The anterior part is split into (1) a centro-levator area of SM cells localized between the right and left LAM, (2) an endo-levator area that upholsters the internal aspect of the LAM, and (3) an infra-levator area below the LAM. All these areas are innervated by autonomic nerves coming from the inferior hypogastric plexus. The core and the infra-levator area receive the cavernous nerve and nerves supplying the urethra. We thus demonstrate that these muscular structures are smooth and under autonomic influence. These findings are relevant for the pelvic surgeon, and especially the urologist, during radical prostatectomy, abdominoperineal resection and intersphincteric resection. Clin. Anat., 2019. © 2019 Wiley Periodicals, Inc.     

全直肠系膜切除相关盆自主神经的解剖学观察

目的：阐述全直肠系膜切除术相关盆自主神经的局部解剖学特点，探讨盆自主神经保留的部位和对策。方法：对20具男性盆腔固定标本进行解剖观察。结果：腹主动脉丛远离肠系膜下动脉起点；上腹下丛贴近骶岬表面；腹下神经部分毗邻输尿管；盆内脏神经伴行直肠中动脉外侧部；下腹下丛位于直肠系膜后外侧；其直肠侧支走行于直肠侧韧带内，直肠前支向前穿过Denonvilliers筋膜后叶；勃起神经位于Denonvilliers筋膜前叶外侧部。结论：盆自主神经保留的部位是：离断肠系膜下血管时的腹主动脉丛左干，直肠后分离时的上腹下丛和腹下神经，直肠侧面分离时的下腹下丛和盆内脏神经，直肠前分离时的勃起神经。共同原则是：在直肠后间隙中贴近直肠系膜操作；直视下操作；避免过度牵引直肠系膜。     

直肠癌患者及健康人群直肠及周围解剖结构的高分辨MRI观察

目的 应用高分辨MRI观察直肠肠壁及其周围解剖细节,为直肠癌的临床诊断和治疗提供解剖参数和依据。 方法 收集60名健康人及20例直肠癌患者的盆腔多序列参数MRI;两位高年资医师行双盲法阅片,对20例直肠癌患者行术前T分期并与术后病理对照,分析准确率;统计分析60名正常人直肠固有筋膜前、后、左、右侧的MRI显示率,以及所有研究对象的骶前筋膜、骶骨筋膜、腹膜返折、直肠侧韧带、下腹下丛的MRI显示率。结果 高分辨MRI可以清楚地显示直肠壁的黏膜层、黏膜下层和固有肌层,直肠癌术前T分期的总准确率为80%（16/20）。健康人直肠固有筋膜前、后、左、右侧的MRI显示率分别为71.7% （43/60）、96.7%（58/60）、90.0%（54/60）和83.3%（56/60）。Denonvillier′s筋膜、骶前筋膜、直肠骶骨筋膜、腹膜返折及下腹下丛的MRI显示率分别为68.8%（55/80）、65.0%（52/80）、87.8%（69/80）、86.3%（69/80）和90.0%（72/80）;直肠侧韧带的显示率较低,左侧为53.8%（43/80）,右侧为47.6%（38/80）。结论 高分辨MRI可以辨识直肠肠壁及其周围解剖细节,帮助直肠癌术前T分期及制定临床治疗方案,判断全直肠系膜切除手术的侧切缘是否浸润,提高微转移癌灶的手术切除率,减少手术并发症。     

Anatomy of the presacral venous plexus: implications for rectal surgery

The presacral venous plexus results from anastomoses between the lateral and median sacral veins, and courses into the pelvic fascia covering the anterior aspect of the body of the sacrum. The presacral venous plexus is not directly visible during rectal surgery, and injuries to this plexus may be life-threatening. Dissection of the retrorectal plane or anchoring of the rectum to the sacral promontory as in rectal prolapse surgery exposes the patient to the risk of injury to the presacral venous plexus. The aim of this study was to identify some avascular areas in the anterior aspect of the sacrum in order to lower the occurrence of such injuries during rectal surgery. The pelvis of 10 fresh cadavers was dissected after injection of a colored resin into the inferior vena cava, and the presacral venous plexus was studied. Four avascular tetragonal areas were common to all the specimens. The corners of a square with a side of 3 cm, centered on the anterior aspect of the body of sacrum, were always contained in the avascular areas. The upper side of this square was parallel to a line passing through the sacral promontory, at a 3 cm distance from it. Staples or sutures should be placed in the avascular areas to avoid injuries to the presacral venous plexus.     

Topography of the pelvic autonomic nerves in human fetuses between 21-29 weeks of gestation

Summary A topographical study concerning the autonomic nerves in the pelvis of human fetuses was performed by investigating 300–600 m thick sections through fetal pelves, impregnated with the epoxy resin E 12 and cut with a diamond wire-saw. In addition the inferior hypogastric plexus of a 26-week old male fetus was dissected by lateral approach. In 21–29-week old fetuses the pelvic autonomic nerves are relatively thick. Thus the nerves stand out well against surrounding structures and their topographical relationships can exactly be determined. The inferior hypogastric plexus of 21–29-week old fetuses is situated on a curved line between the rectum and the ventrally adjacent structure. It constitutes a rectangular plate, which cannot be subdivided into individual plexuses for the different pelvic organs. The fetal plexus is heavily ganglionated. Large ganglia, forming the so-called ganglion of Frankenhaeuser, are found in the female as well as in the male fetus. In the fetal pelvis the connective tissue compartments are still clearly arranged, because adipose tissue is not yet abundant. The greater part of the inferior hypogastric plexus is situated exactly at the border between a dense visceral tissue medially and a loose parietal tissue laterally. The plexus does not share a common connective tissue cover with the pelvic blood vessels. In fetuses the inferior hypogastric plexus lies in close vicinity to serveral organs, but the pelvic floor is the only region where the nerves can hardly be separated from the surrounding structures.     

Fascial structures and autonomic nerves in the female pelvis: A study using macroscopic slices and their corresponding histology

We investigated the topographical anatomy of the pelvic fasciae and autonomic nerves using macroscopic slices of five decalcified female pelves. The lateral aspect of the supravaginal cervix uteri and superior-most vagina issued abundant thick fiber bundles. These visceral fibrous tissues extended dorsolaterally, joined another fibrous tissue from the rectum (the actual lateral ligament of the rectum) and attached to the parietal fibrous tissues at and around the sciatic foramina (i.e. the sacrospinous ligament, thick fasciae of the coccygeus and piriformis and dorsal end of the covering fascia of the levator ani). The inferior or ventral vagina also issued thick fiber bundles communicating with the levator ani fascia. This connection between the vagina and levator fascia, when stretched, seemed to provide a macroscopic morphology called the arcus tendineus fasciae pelvis. The overall morphology of the visceroparietal fascial bridge exhibited a bilateral wing-like shape. The fascial bridge complex was adjacent but dorso-inferior to the internal iliac vascular sheath and located slightly ventral to the pelvic splanchnic nerve. However, the pelvic plexus and its peripheral branches were embedded in the fascial complex. The hypogastric nerve ran along and beneath the uterosacral peritoneal fold, which did not contain thick fibrous tissue. During surgery, in combination with the superficially located vascular sheath, the morphology of the visceroparietal fascial bridge and associated nerves seemed to be artificially changed and developed into the so-called cardinal, uterosacral, uterovesical and/or rectal lateral ligaments. The classical and original concepts of these pelvic fascial structures may need to be altered to adjust to these surgical observations.     

男性盆腔内脏神经的解剖学研究及其临床意义

男性盆腔内脏神经与盆筋膜及盆内脏器的毗邻关系复杂,且个体形态学差异大,临床上涉及肛肠外科、泌尿外科、男科等多个学科,应用甚广。近年来,对内脏神经的术中保护越来越受到重视。男性盆腔内脏神经主要包括上腹下丛、腹下神经、下腹下丛(即盆丛)、盆内脏神经、膀胱丛、前列腺丛、直肠丛及其分支等。现已证明盆腔内脏神经的损伤会给患者的排便、排尿及阴茎勃起等造成功能障碍。熟悉男性盆腔内脏神经及其分支的形态特点及其与周围结构的关系,能降低手术并发症,提高患者术后生活质量。     

Clinical anatomy study of autonomic nerve with respective to the anterior approach lumbar surgery

Introduction  Male genital dysfunction was recognized as a complication following anterior approach lumbar surgery. Disruption of efferent sympathetic pathways such as the abdominal aortic plexus (AAP) and superior hypogastric plexus (SHP) which lied pre-abdominal aorta and iliac artery had been thought as the main reason. Though there were some clinical reports of retrograde ejaculation, the applied anatomic study of the autonomic nerve anterior to the lumbar was little. The purpose was to find out a lumbar surgery approach which was ejaculation preservation through the detailed study of the anatomy and histology observation of the autonomic nerve anterior to the lumbar vertebrae. Methods  The lumbar region of ten male cadavers was dissected and analyzed. We investigated the relationship between the peritoneum and abdominal aorta, iliac artery and sacral promontory fascia, as well as the trend and distribution of the autonomic nerve and SHP anterior to the L5-S1. We also observed the distribution of autonomic nerve at retroperitoneum through hematoxylin and eosin (HE)-stained tissues pre-aorta, para-aorta, and pre-vertebrae sacrales. Results  Superior hypogastric plexus, which deviated to left, located in a triangle formed by the common iliac arteries and its bilateral branches, its truck sited anterior to the lumbarsacral space in seven cases (70%), and anterior to sacrum in three cases (30%); at the aortic bifurcation, SHP strided over left iliac artery from left-hand side, then located in front of sacrum in four cases (40%), and sifted to the left at the lumbar sacral promontory in six cases (60%); from both anatomic and histological view, the autonomic nerve plexus lying in an fascia layer of retroperitoneum. Conclusion  At the anterior approach lumbar surgery of trans-peritoneum, we should choose the right-hand side incision; the SHP should be pushed aside carefully from right to left along intervertebral disc. The accurate surgical plane was at the deeper layer of autonomical nerve fascia; we also could lift the complete autonomical nerve layer which lies behind the aorta and lumbar sacral promontory, so that the autonomic nerve could be preserved.     

Topography of the pelvic autonomic nervous system and its potential impact on surgical intervention in the pelvis

Bladder, bowel, and sexual dysfunction caused by iatrogenic lesions of the inferior hypogastric plexus (IHP) are well known and commonly tolerated in pelvic surgery. Because the pelvic autonomic nerves are difficult to define and dissect in surgery, and their importance often ignored, we conducted a gross anatomic study of 90 adult and four fetal hemipelves. Using various non-surgical approaches, the anatomic relations and pathways of the IHP were dissected. The IHP extended from the sacrum to the genital organs at the level of the lower sacral vertebrae. It originated from three different sources: the hypogastric nerve, the sacral splanchnic nerves from the sacral sympathetic trunk (mostly the S2 ganglion), and the pelvic splanchnic nerves, which branched primarily from the third and fourth sacral ventral rami. These fibers converge to form a uniform nerve plate medial to the vascular layer and deep to the peritoneum. The posterior portion of the IHP supplied the rectum and the anterior portion of the urogenital organs; nerve fibers traveled directly from the IHP to the anterolateral wall of the rectum and to the inferolateral and posterolateral aspects of the urogenital organs. The autonomic supply from the IHP was supplemented by nerves accompanying the ureter and the arteries. An understanding of the location of the autonomic pelvic network, including important landmarks, should help prevent iatrogenic injury through the adoption of surgical techniques that reduce or prevent postoperative autonomic dysfunction.     

The surgical anatomy of the fasciae and the fascial spaces related to the rectum

The perirectal fasciae and their vascular and neural relationships were studied based on the dissection of 46 fresh cadavers. The rectal fascia is a tubular sleeve, areolar in nature, which houses the superior rectal vessels and lymphatics. The nerves which supply fibres to the pelvic plexus run close to the rectum, contained in the urogenital and presacral fasciae. The rectum is attached to these two fasciae by the rectal stalks, which take a spiral course round the rectum, being posterolateral in the upper rectum, lateral in the mid-rectum and anterolateral in the lower rectum. During rectal resection the pelvic nn. may be preserved if the rectal dissection proceeds close to the rectal fascia. After cutting the rectal insertion of the presacral fascia, the lower rectal stalks (paraproctium) come into direct view and can be divided close to the rectal wall with no risk of damage to the pelvic plexus.     

Extrinsic innervation of the pelvic organs in the lesser pelvis of human embryos

Realistic models to understand the developmental appearance of the pelvic nervous system in mammals are scarce. We visualized the development of the inferior hypogastric plexus and its preganglionic connections in human embryos at 4–8 weeks post-fertilization, using Amira 3D reconstruction and Cinema 4D-remodelling software. We defined the embryonic lesser pelvis as the pelvic area caudal to both umbilical arteries and containing the hindgut. Neural crest cells (NCCs) appeared dorsolateral to the median sacral artery near vertebra S1 at ~5 weeks and had extended to vertebra S5 1 day later. Once para-arterial, NCCs either formed sympathetic ganglia or continued to migrate ventrally to the pre-arterial region, where they formed large bilateral inferior hypogastric ganglionic cell clusters (IHGCs). Unlike more cranial pre-aortic plexuses, both IHGCs did not merge because the 'pelvic pouch', a temporary caudal extension of the peritoneal cavity, interposed. Although NCCs in the sacral area started to migrate later, they reached their pre-arterial position simultaneously with the NCCs in the thoracolumbar regions. Accordingly, the superior hypogastric nerve, a caudal extension of the lumbar splanchnic nerves along the superior rectal artery, contacted the IHGCs only 1 day later than the lumbar splanchnic nerves contacted the inferior mesenteric ganglion. The superior hypogastric nerve subsequently splits to become the superior hypogastric plexus. The IHGCs had two additional sources of preganglionic innervation, of which the pelvic splanchnic nerves arrived at ~6.5 weeks and the sacral splanchnic nerves only at ~8 weeks. After all preganglionic connections had formed, separate parts of the inferior hypogastric plexus formed at the bladder neck and distal hindgut.     

Preservation of Denonvilliers' fascia for nerve‐sparing laparoscopic total mesorectal excision: A neuro‐histological study

Urogenital complications due to pelvic autonomic nerve damage frequently occur following rectal surgery. We investigated whether total mesorectal excision (TME) with preservation of the Denonvilliers' fascia (DVF) can effectively prevent the removal of pelvic autonomic nerves through microscopy. Twenty consecutive male patients with mid‐low rectal cancer who received TME with preservation or resection of the Denonvilliers' fascia (P and R groups, respectively) were included. Serial transverse sections from surgical specimens were studied histologically. Nerve fibers at the surfaces of the mesorectum were counted. Clinical correlation between the amount of nerve fibers removed and post‐operative sexual function was analyzed. Nerve fibers closely localized to the DVF in the R group displaying rich erectile activity (positive anti‐nNOS immunostaining). At the anterior surface of the mesorectum, the mean numbers of nNOS‐positive nerve fibers per specimen in the P group were significantly lower than the R group (3.0 ± 1.8 vs. 5.0 ± 2.3, P < 0.05). Compared to the R group, patients in the P group had higher IIEF scores and better erectile function at 3 and 6 months post‐operatively. The DVF is a key risk zone for pelvic denervation during laparoscopic TME. Preservation of the DVF can prevent the removal of autonomic nerves and protect post‐operative erectile function. Clin. Anat. 32:439–445, 2019. © 2019 Wiley Periodicals, Inc.