Nerve fibers in uterosacral ligaments of women with deep infiltrating endometriosis

Urodynamic Profile and Impact of Surgery in Women Affected by Deep Infiltrating Endometriosis: a Systematic Review and Meta-analysis

OBJECTIVE

to evaluate the impact of deep infiltrating endometriosis (DIE) on bladder function and the possible impact of surgical resection.

DATA SOURCES

A systematic literature research was performed using the PubMed/MEDLINE and EMBASE database (last search date: 30 April 2024).

METHODS OF STUDY SELECTION

we included studies that evaluated the urodynamics (UDS) findings in women affected by DIE before submission to surgery. Following epidemiological designs were considered suitable: randomized control trials (RCTs), observational prospective or retrospective studies and case series. Metanalysis was performed using Jamovi Software version 2.3.28 (Sydney, Australia), according to PRISMA 2020 guidelines. Nine publications were included.

TABULATION, INTEGRATION, AND RESULTS

Nine studies including 574 women affected by DIE and submitted to urodynamic assessment were included. In women affected by DIE, preoperative detrusor overactivity (DO) was reported in 15% (95% CI 3, 26; I2=93.9%, p<0.001), preoperative voiding dysfunction in 21% (95% CI 12, 29; I2=78.1%, p<0.001) and preoperative low maximum cystometry capacity was shown in 18% (95% CI -2, 38; I2=97.2%, p<0.001). An abnormal bladder sensation was recorded in 39% of patients (95% CI 18, 60; I2=86%, p<0.001), low preoperative bladder compliance was reported in 35% of patient (95% CI 30, 40; I2=0%, p=0.66) and preoperative painful bladder filling was showed in 37% of the evaluated population (95% CI 27, 48; I2=0%, p=0.58). No difference between preoperative and postoperative UDS DO was reported (OR 0.45; 95% CI -0.10, 1.0, I2=0%; p=0.66). Moreover, no difference in preoperative and postoperative voiding dysfunction was reported (OR 0.0; 95% CI -0.76, 0.76, I2=49.6%; p=0.12).

CONCLUSION

Abnormal urodynamic findings before surgery are prevalent in women with deep infiltrating endometriosis. Surgery seems not affect UDS outcomes in women affected by DIE. However, heterogeneity among included studies may limit the generalizability of our findings.

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.

Endometriosis and Pelvic Pain for the Gastroenterologist

Endometriosis, affecting 5-10% of reproductive-age women, is a common contributor to dysmenorrhea and chronic pelvic pain. Diagnosis requires laparoscopic tissue biopsy, but careful pelvic examination, and/or imaging with either ultrasound or MRI, may identify patients who should receive empiric first-line therapy. The presence of dyschezia, particularly with cyclical exacerbation, should raise suspicion for bowel or rectovaginal septum involvement, and a greater need for surgical management. Treatment of dysmenorrhea includes hormonal suppression of the menstrual cycle, and/or analgesics; more severe cases with strong pain and disability may require earlier surgical intervention to excise disease while preserving fertility desires.

Is the Deep Endometriosis or the Surgery the Cause of Postoperative Bladder Dysfunction?

STUDY OBJECTIVE

To assess if deep endometriosis surgery affects the bladder function.

DESIGN

Prospective multicenter observational study (Canadian Task Force classification II-2).

SETTING

Academic researches centers.

PATIENTS

Thirty-two patients with diagnosis of deep endometriosis requiring surgery.

INTERVENTIONS

Women were evaluated with urodynamic studies, ICIQ-UI SF and ICIQ-OAB questionnaires before and 3 months after surgery.

MEASUREMENTS AND MAIN RESULTS

The main outcome measure was the impact of deep endometriosis surgery on urodynamic parameters. All cystomanometric parameters showed an improvement postoperatively: in particular, the first desire to void (120 vs 204 ml, p<0.001) and the bladder capacity (358 vs 409 ml, p=0.011) increased significantly after surgery. Of the uroflow parameters, the maximal voiding flow improved significantly postoperatively (19 vs 25 ml/sec, p=0.026). The ICIQ-UI SF (2.5 vs 0, p=0.0005) and ICIQ-OAB (4.3 vs 1.2, p<0.001) questionnaires showed a significant postoperative improvement too.

CONCLUSIONS

Our data show that in a selected population of patients with DE (not requiring bowel or urethral resection), the bladder function improves after surgery, both during filling and on voiding urodynamic phases. Postoperatively, patients with DE become aware of bladder filling later, have a higher bladder capacity and have a higher maximal flow. The postoperative urodynamic results are corroborated by the improved scores on the bladder questionnaires.

Autonomic nervous system and inflammation interaction in endometriosis-associated pain

Endometriosis is a chronic inflammatory disease. Pain is the most common symptom in endometriosis. Endometriosis-associated pain is caused by inflammation, and is related to aberrant innervation. Although the specific mechanism between endometriosis-associated pain and the interaction of aberrant innervation and inflammation remains unclear, many studies have confirmed certain correlations between them. In addition, we found that some chronic inflammatory autoimmune diseases (AIDs) such as inflammatory bowel disease (IBD) and rheumatoid arthritis (RA) share similar characteristics: the changes in dysregulation of inflammatory factors as well as the function and innervation of the autonomic nervous system (ANS). The mechanisms underlying the interaction between the ANS and inflammation have provided new advances among these disorders. Therefore, the purpose of this review is to compare the changes in inflammation and ANS in endometriosis, IBD, and RA; and to explore the role and possible mechanism of sympathetic and parasympathetic nerves in endometriosis-associated inflammation by referring to IBD and RA studies to provide some reference for further endometriosis research and treatment.

Estrogen is an important mediator of mast cell activation in ovarian endometriomas

Endometriosis is an estrogen-dependent disease. Previous research has shown that abnormal enzymes associated with estrogen (E2) metabolism and an increased number of mast cells (MCs) in endometriomas are implicated in the pathogenesis of endometriosis. However, it remains unclear how MCs mediate the role of E2 in endometriosis. Accordingly, we investigated whether E2 was associated with the number of MCs, and the rate of degranulation, in local ovarian endometriomas, as well as the role of E2 on MCs during the pathogenesis of endometriosis. Using enzyme-linked immunosorbent assay and immunohistochemistry, we found that concentrations of E2, and the number and activity of MCs, were significantly higher in ovarian endometriomas than in controls, and that these parameters were correlated with the severity of endometriosis-associated dysmenorrhea. By measuring the release of hexosaminidase, we found that the rate of RBL2H3 cell degranulation increased after E2 treatment. Furthermore, activation of RBL2H3 cells by E2 was found to trigger the release of biologically active nerve growth factor, which promotes neurite outgrowth in PC12 cells and also sensitizes dorsal root ganglion cells via upregulation ofNav1.8and transient receptor potential cation channel (subfamily V member 1) expression levels. When treated with E2, endometriotic cells could promote RBL2H3 cell recruitment by upregulating expression levels of stem cell factor, transforming growth factor-β and monocyte chemoattractant protein-1; these observations were not evident with control endometrial cells. Thus, elevated E2 concentrations may be a key factor for degranulation and recruitment of MCs in ovarian endometriomas, which play a key role in endometriosis-associated dysmenorrhea.

Nerve fibers and endometriotic lesions: partners in crime in inflicting pains in women with endometriosis

One of major objectives in treating endometriosis is to alleviate pain since dysmenorrhea and other types of pain top the list of complaints from women with endometriosis who seek medical attention. Indeed, endometriosis-associated pain (EAP) is the most debilitating of the disease that negatively impacts on the quality of life in affected women, contributing significantly to the burden of disease and adding to the substantial personal and societal costs. Unfortunately, the mechanisms underlying the EAP are still poorly understood. In the last two decades, one active research field in endometriosis is the investigation on the distribution and genesis of nerve fibers in eutopic and ectopic endometrium, and the attempt to use endometrial nerve fiber density for diagnostic purpose. Since EAP presumably starts with the terminal sensory nerves, in or around endometriotic lesions, that transduce noxious mediators to the central nervous system (CNS) which ultimately perceives pain, this field of research holds the promise to elucidate the molecular mechanisms underlying the EAP, thus opening new avenues for novel diagnostics and therapeutics. In this review, we shall first briefly provide some basic facts on nerve fibers, and then provide an overview of some major findings in this filed while also note some conflicting results and expose areas in need of further research. We point out that since recently accumulated evidence suggests that endometriotic lesions are wounds undergoing repeated tissue injury and repair, the relationship between endometriotic lesions and nerve fibers is not simply unidirectional, i.e. lesions promote hyperinnervations. Rather, it is bidirectional, i.e. endometriotic lesions and nerve fibers engage active cross-talks, resulting in the development of endometriosis and pain. That is, nerve fibers and endometriotic lesions are actually partners in crime in inflicting pains in women with endometriosis, aided and abetted possibly by other culprits, some yet to be identified. We provide a list of possible perpetrators likely to be involved in this crime. Finally, we discuss possible implications when viewing the relationship from this vista.

Magnetic resonance imaging evidence for perineural spread of endometriosis to the lumbosacral plexus: report of 2 cases

Sciatic nerve endometriosis (EM) is a rare presentation of retroperitoneal EM. The authors present 2 cases of catamenial sciatica diagnosed as sciatic nerve EM. They propose that both cases can be explained by perineural spread of EM from the uterus to the sacral plexus along the pelvic autonomie nerves and then further distally to the sciatic nerve or proximally to the spinal nerves. This explanation is supported by MRI evidence in both cases. As a proof of concept, the authors retrieved and analyzed the original MRI studies of a case reported in the literature and found a similar pattern of spread. They believe that the imaging evidence of their institutional cases together with the outside case is a very compelling indication for perineural spread as a mechanism of EM of the nerve.

The importance of pelvic nerve fibers in endometriosis

Several lines of recent evidence suggest that pelvic innervation is altered in endometriosis-affected women, and there is a strong presumption that nerve fibers demonstrated in eutopic endometrium (of women with endometriosis) and in endometriotic lesions play roles in the generation of chronic pelvic pain. The recent observation of sensory C, sensory A-delta, sympathetic and parasympathetic nerve fibers in the functional layer of endometrium of most women affected by endometriosis, but not demonstrated in most women who do not have endometriosis, was a surprise. Nerve fiber densities were also greatly increased in myometrium of women with endometriosis and in endometriotic lesions compared with normal peritoneum. Chronic pelvic pain is complex, and endometriosis is only one condition which contributes to this pain. The relationship between the presence of certain nerve fibers and the potential for local pain generation requires much future research. This paper reviews current knowledge concerning nerve fibers in endometrium, myometrium and endometriotic lesions, and discusses avenues of research that may improve our knowledge and lead to enriched understanding and management of endometriotic pain symptoms.

Decreased nerve fibers in the oviduct isthmus of women with endometriosis

Oviduct tubal motility is thought to be controlled by hormones and nerves and has been associated with endometriosis. However, it is still not known whether the fallopian tubes in women with endometriosis demonstrate an abnormal distribution of nerve fibers. The objective of this study was to determine the distribution of nerve fibers in the oviduct isthmus in women with and without endometriosis. Histological sections of the oviduct isthmus tissues were obtained from women undergoing hysterectomy for endometriosis (n=24) and other benign gynecologic diseases (n=24). The tissues were immunohistochemically stained for protein gene product (PGP) 9.5, substance P (SP), neuropeptide Y (NPY), and vasoactive intestinal peptide (VIP) to reveal all nerve fibers, sensory nerve fibers and sympathetic and parasympathetic nerve fibers. Nerve fibers stained with PGP9.5, VIP and NPY in the oviduct isthmus were all significantly decreased in women with endometriosis as compared with women without endometriosis (P<0.05). In women with endometriosis, reduced nerve fibers stained with PGP9.5 and SP in the serosal layer, NPY in the muscular and mucosal layers, and VIP in the mucosal layer of the oviduct isthmus were all associated with the severity of the disease (P<0.05). These results suggest that decreased nerve fibers in the oviduct isthmus in women with endometriosis in comparison to women without may imply a role in the pathogenesis of endometriosis.

Peripheral changes in endometriosis-associated pain

BACKGROUND

Pain remains the cardinal symptom of endometriosis. However, to date, the underlying mechanisms are still only poorly understood. Increasing evidence points towards a close interaction between peripheral nerves, the peritoneal environment and the central nervous system in pain generation and processing. Recently, studies demonstrating nerve fibres and neurotrophic and angiogenic factors in endometriotic lesions and their vicinity have led to increased interest in peripheral changes in endometriosis-associated pain. This review focuses on the origin and function of these nerves and factors as well as possible peripheral mechanisms that may contribute to the generation and modulation of pain in women with endometriosis.

METHODS

We conducted a systematic search using several databases (PubMed, MEDLINE, EMBASE and CINAHL) of publications from January 1977 to October 2013 to evaluate the possible roles of the peripheral nervous system in endometriosis pathophysiology and how it can contribute to endometriosis-associated pain.

RESULTS

Endometriotic lesions and peritoneal fluid from women with endometriosis had pronounced neuroangiogenic properties with increased expression of new nerve fibres, a shift in the distribution of sensory and autonomic fibres in some locations, and up-regulation of several neurotrophins. In women suffering from deep infiltrating endometriosis and bowel endometriosis, in which the anatomical distribution of lesions is generally more closely related to pelvic pain symptoms, endometriotic lesions and surrounding tissues present higher nerve fibre densities compared with peritoneal lesions and endometriomas. More data are needed to fully confirm a direct correlation between fibre density in these locations and the amount of perceived pain. A better correlation between the presence of nerve fibres and pain symptoms seems to exist for eutopic endometrium. However, this appears not to be exclusive to endometriosis. No correlation between elevated neurotrophin levels and pain severity appears to exist, suggesting the involvement of other mediators in the modulation of pain.

CONCLUSIONS

The increased expression of neurotrophic factors and nerve fibres in endometriotic lesions, eutopic endometrium and the peritoneum imply a role of such peripheral changes in the pathogenesis of endometriosis-associated pain. However, a clear link between these findings and pain in patients with endometriosis has so far not been demonstrated.

Loss of nerve fibers in the oviduct isthmus in women with hydrosalpinx

Apart from the abnormalities of tubal anatomy, the main concern linked to infertility is impaired tubal motility associated with hydrosalpinx, which is thought to be controlled by hormones and nerves. The objective of this study was to determine the distribution of nerve fibers in the oviduct isthmus in women with and without hydrosalpinx. Histological sections of the oviduct isthmus tissue were obtained from 18 women undergoing salpingectomy for hydrosalpinx, and from 15 women undergoing hysterectomy and salpingectomy for benign gynecologic diseases. The tissues were immunohistochemically stained for protein gene product (PGP) 9.5, protein S100, neuropeptide tyrosine (NPY), and vasoactive intestinal peptide (VIP) to reveal all nerve fibers, as well as sympathetic and parasympathetic nerve fibers, in the oviduct isthmus. We detected the presence of PGP9.5, S100, VIP, and NPY-immunoreactive nerve fibers in the oviduct isthmus in all study subjects. However, the densities of PGP9.5, S100, VIP, and NPY-immunoreactive nerve fibers in the oviduct isthmus were all significantly decreased in women with hydrosalpinx compared with those in women without hydrosalpinx (P<0.01). Our results suggest that reduced nerve fibers in the oviduct isthmus in women with hydrosalpinx compared with women without hydrosalpinx may have an important function in the mechanism of hydrosalpinx-associated infertility.

[Uterosacral ligament and hypogastric nerve anatomical relationship. Application to deep endometriotic nodules surgery]

Endometriosis is a concern for 10 to 15% of women of childbearing age. The uterosacral ligament is the most frequent localization of deep infiltrating endometriosis. Laparoscopic excision of endometriotic nodules may lead to functional consequences due to potential hypogastric nerve lesion. Our aim is to study the anatomical relationship between the hypogastric nerve and the uterosacral ligament in order to reduce the occurrence of such nerve lesions during pelvic surgeries. We based our study on an anatomical and surgical literature review and on the anatomical dissection of a 56-year-old fresh female subject. The hypogastric nerves cross the uterosacral ligament approximately 30mm from the torus. They go through the pararectal space, 20mm below the ureter and join the inferior hypogastric plexus at the level of the intersection between the ureter and the posterior wall of the uterine artery, at approximately 20mm from the torus. No anatomical variation has been described to date in the path of the nerve, but in its presentation which may be polymorphous. Laparoscopy and robot-assisted laparoscopic surgery facilitate the pelvic nerves visualization and are the best approach for uterosacral endometriotic nodule nerve-sparing excision. Precise knowledge by the surgeon of the anatomical relationship between the hypogastric nerve and the uterosacral ligament is essential in order to decrease the risk of complication and postoperative morbidity for patient surgically treated for deep infiltrating endometriosis involving uterosacral ligament.

Visual pain mapping in endometriosis

PURPOSE

To construct pain maps in order to describe the distribution of pelvic pain in a group of endometriosis patients and endometriosis-free patients, to assess the feasibility of this method.

METHODS

A total of 159 patients with pelvic pain who were scheduled for diagnostic laparoscopy.

RESULTS

A total of 117 patients with and 42 patients without endometriosis were included. The pain distribution between these two patient groups appeared to differ in some peripheral anatomical structures. In the endometriosis patients, the pain was most frequently located in the rectouterine pouch.

CONCLUSIONS

In endometriosis patients, pain mapping to assess preoperative pain sensations relative to the anatomic location of endometriotic lesions is feasible. The pain provoked by vaginal examination is frequently perceived as median relative to the actual anatomic location of the endometriotic lesions. Several anatomic and neurophysiological factors may explain this phenomenon.

Distribution of substance P (SP) and vasoactive intestinal peptide (VIP) in pseudocapsules of uterine fibroids

The authors examined the presence of Substance P (SP) and Vasoactive Intestinal Polypeptide (VIP) and their related fibers in the pseudocapsule of uterine fibroids (PUF) and in normal myometrium (NM) during myomectomies in 57 non-pregnant women. 4 samples were removed from the normal myometrium (NM) and from PUF. The samples were sent for histological and immune-fluorescent investigations. SP and VIP values were found non-significantly higher in PUF than in NM: SP values were 10.2±0.1 conventional units (C.U.) in PUF at the fundus of the uterus (FU) vs. 8.1±0.6C.U. of NM in the FU (p>0.05), and SP values were 25.1±0.9C.U. in PUF in the uterine body (UB) compared to. 23.2±1.4C.U. of NM in the myometrium of the UB (p>0.05). VIP values were 11.5±0.9C.U. in the PUF in FU compared to 9.8±1.4C.U. of NM in the FU (p>0.05), and VIP values were 33.9±3.9C.U. in the PUF in the UB vs. 32.6±4.8C.U. of the NM in the UB (p>0.05). These findings show that SP and VIP neurofibers are present in the fibroid pseudocapsule, similar to the values in the normal myometrium of a non-pregnant uterus. An intracapsular myoma excision which respects the pseudocapsule permits a physiological healing process of the uterine scar, due to a neurotransmitter sparing at the hysterotomic site. In women planning pregnancy, the myomectomy should be preferably performed respecting the pseudocapsule in order to preserve the neurotransmission.

Autonomic denervation and the origins of chronic Western diseases

Many chronic Western diseases result from lifestyles that include refined diets, poor bowel habits, limited physical exercise and suboptimal patterns of childbirth. Western diets result in reduced stool weights, increased bowel transit times and persistent physical efforts during defaecation. Prolonged physical efforts during defaecation and childbirth cause latent, or direct, injuries to branches of the cardiac (thorax), coeliac (abdomen) and hypogastric (pelvis) plexi. Injuries to autonomic nerves result in impaired visceral function including visceral dysmotility, tissue hypoplasia and hyperplasia, increased susceptibility to infection, and, aberrant reinnervation with sensitisation of the central nervous system (CNS). These unrecognised injuries are vulnerable to the long list of causes of autonomic Dysfunction, e.g. stress, alcohol, drugs, infection, trauma, cancer, etc. Specific injuries at different anatomical locations in midline autonomic pathways give rise to a wide range of Western diseases from infancy to old age, through diverse and cumulative mechanisms.