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

Novel Concepts on the Functional Neuroanatomy of the Anorectum: Implications for Anorectal Neuropathy and Neuromodulation Therapy

Anorectal neuropathy causes anorectal dysfunction, yet it is poorly recognized. This stems from both a lack of understanding of the extrinsic and intrinsic innervation of the anorectum and tools for evaluation of neuronal function. Our objective was to provide an improved understanding of the neuronal networks of the anorectum and discuss its functional significance. We performed a comprehensive and up-to-date review of the published literature on anorectal neuroanatomy to generate our findings. Anorectal nerve innervation appears to be much more complex than hitherto known with an extensive overlap, intercommunications, and variations. The innervations arise from 5 sources as evidenced by immunohistochemical markers: Sympathetic innervation arises from the superior hypogastric plexus, hypogastric plexus, and splanchnic nerves (T1-L2); the parasympathetic from pelvic splanchnic nerves (S1-S4); the mixed autonomic from inferior hypogastric plexus; the somatic from pudendal nerves; and the intercommunicating nerves. Furthermore, they are fine, closely packed nerves susceptible to damage from obstetric or spinal cord injury, or pelvic surgery that may not manifest with bowel problems immediately but later in life. This illustrated review provides a new understanding of the afferent and efferent pathways between the rectum, spinal cord, and brain, and a framework for clinical implications of anorectal neuropathy, such as anal sphincter or rectal sensory or rectal accommodation dysfunction, causing bowel problems. Insights into the functional neuroanatomy provide an improved mechanistic understanding of anorectal symptoms and could facilitate the development of neurophysiological tests such as translumbosacral anorectal magnetic stimulation and neuromodulation treatments such as sacral neuromodulation and translumbosacral neuromodulation treatment.

Advanced Insights into Human Uterine Innervation: Implications for Endometriosis and Pelvic Pain

(1) Background: Understanding uterine innervation, an essential aspect of female reproductive biology, has often been overlooked. Nevertheless, the complex architecture of uterine innervation plays a significant role in conditions such as endometriosis. Recently, advances in histological techniques have provided unprecedented details about uterine innervation, highlighting its intricate structure, distribution, and density. The intricate nature of uterine innervation and its influence on pathologies such as endometriosis has garnered increasing attention. (2) Objectives: This review aims to compile, analyze, and summarize the existing research on uterine innervation, and investigate its implications for the pathogenesis of endometriosis and associated pain. (3) Methods: A systematic review was conducted in line with PRISMA guidelines. Using the PubMed database, we searched relevant keywords such as "uterine innervation", "endometriosis", and "pain association". (4) Results: The initial literature search yielded a total of 3300 potential studies. Of these, 45 studies met our inclusion criteria and were included in the final review. The analyzed studies consistently demonstrated that the majority of studies focused on macroscopic dissection of uterine innervation for surgical purposes. Fewer studies focused on micro-innervation for uterine innervation. For endometriosis, few studies focused on neural pain pathways whereas many studies underlined an increase in nerve fiber density within ectopic endometrial tissue. This heightened innervation is suggested as a key contributor to the chronic pain experienced by endometriosis patients. (5) Conclusions: The understanding of uterine innervation, and its alterations in endometriosis, offer promising avenues for research and potential treatment.

The 3D reconstructions of female pelvic autonomic nerves and their related organs based on MRI: a first step towards neuronavigation during nerve-sparing radical hysterectomy

OBJECTIVES

To present in vivo female pelvic autonomous innervation and the relationship between nerves and their related organs by three-dimensional (3D) reconstruction based on magnetic resonance imaging (MRI).

METHODS

Thirty patients with cervical cancer who underwent pelvic MRI and agreed to undergo additional magnetic resonance neurography (MRN) sequences were enrolled in the present study. MRI images from the same patient were acquired using T2-weighted fat saturation (T2W FS) and 3D-STIR-SPACE sequences. Detailed two-dimensional (2D) segmentation and 3D reconstruction of pelvic autonomic nerves (PAN) were performed on the basis of the images of the two sequences using 3D reconstruction software. The 2D segmentation and 3D reconstruction of pelvic organs were based on T2W FS images. The consistency of the 3D models of pelvic autonomous innervation constructed from the two sequences were analysed and compared, the pelvic autonomous innervation was presented, and the relationship between nerves and their related organs was characterised.

RESULTS

The 3D reconstructions of PAN were successfully obtained from 3D-STIR-SPACE and T2W FS sequences in 30 patients and showed high correspondence. T2W FS images also enabled 3D reconstructions of pelvic organs to visualise the 3D distribution of PAN and the positional relationships between nerves and their related organs.

CONCLUSION

The pelvic autonomic nerves and their related organs can be reconstructed on the basis of MRI to present personalised 3D anatomical information and offer individualised guidance during nerve-sparing radical hysterectomy (NSRH).

KEY POINTS

• Nerve-sparing radical hysterectomy is a developing trend in cervical cancer surgery • MRI allows reconstructions of pelvic autonomic nerves and their related organs • The 3D reconstructions provide detailed 3D anatomical information on nerves.

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.

Chronic visceral pain secondary to ventral disc herniation: Development of visceral complex regional pain syndrome

When an organ disease is ruled out as the origin of pelvic pain, the superior hypogastric plexus (SHP) injury and consequent dysfunction could be the mechanism of visceral chronic pain perpetuation. As much as a dorsal discus herniation may harm the dorsal or ventral roots, a ventral discus herniation at L4-L5 or L5-S1 may result in direct physical trauma to the SHP, maintaining chronic visceral pain mediated by sympathetic dysfunction, conceivably also afferent fibers dysfunction. We propose that similarly to nociceptive somatic dysfunction named complex regional pain syndrome, the maintained sympathetic pelvic pain secondary to straight physical damage to the SHP characterize in fact the same disease, but in nociceptive visceral tissue, named visceral complex regional pain syndrome, a concept constructed based on the International Association for the Study of Pain criteria (1994).

New insights in the neuroanatomy of the human adult superior hypogastric plexus and hypogastric nerves

BACKGROUND

The superior hypogastric plexus (SHP) is an autonomic plexus, located ventrally to the abdominal aorta and its bifurcation, innervating pelvic viscera. It is classically described as being composed of merely sympathetic fibres. However, post-operative complications after surgery damaging the peri-aortic retroperitoneal compartment suggest the existence of parasympathetic fibres. This immunohistochemical study describes the neuroanatomical composition of the human mature SHP.

MATERIAL AND METHODS

Eight pre-determined retroperitoneal localizations including the lumbar splanchnic nerves, the SHP and the HN were studied in four human cadavers. Control tissues (white rami, grey rami, vagus nerve, splanchnic nerves, sympathetic ganglia, sympathetic chain and spinal nerve) were collected to verify the results. All tissues were stained with haematoxylin and eosin and antibodies S100, tyrosine hydroxylase (TH), vasoactive intestinal peptide (VIP) and myelin basic protein (MBP) to identify pre- and postganglionic parasympathetic and sympathetic nerve fibres.

RESULTS

All tissues comprising the SHP and hypogastric nerves (HN) showed isolated expression of TH, VIP and MBP, revealing the presence of three types of fibres: postganglionic adrenergic sympathetic fibres marked by TH, unmyelinated VIP-positive fibres and myelinated preganglionic fibres marked by MBP. Analysis of control tissues confirmed that TH, VIP and MBP were well usable to interpret the neurochemical composition of the SHP and HN.

CONCLUSION

The human SHP and HN contain sympathetic and most likely postganglionic parasympathetic fibres. The origin of these fibres is still to be elucidated, however surgical damage in the peri-aortic retroperitoneal compartment may cause pelvic organ dysfunction related to both parasympathetic and sympathetic denervation.