Endometriosis-Related Pelvic Pain: What is the Evidence?

Long-standing groin pain syndrome in athletic women: a multidisciplinary assessment in keeping with the italian consensus agreement

BACKGROUND

Long-standing groin pain syndrome (LSGPS) is a form of groin pain syndrome in which the cohort of symptoms reported by patients is experienced for a long period, typically for over 12 weeks, and is recalcitrant to any conservative therapy. The aim of this prospective epidemiological study was to describe the clinical causes of LSGPS in 37 female athletic subjects in Italy through the Groin Pain Syndrome Italian Consensus Conference on terminology, clinical evaluation and imaging assessment in groin pain in athletes classification and guidelines.

METHODS

Thirty-seven female athletes affected by LSGPS were evaluated following the guidelines issued by the Groin Pain Syndrome Italian Consensus Conference on terminology, clinical evaluation and imaging assessment of groin pain in athletes.

RESULTS

In the considered population, each patient presented only one pathological cause for LSGPS. The most frequent aetiologies were inguinal pathologies (54.05% of the cases), acetabular labrum tear (18.92%) and pelvic floor disorders (8.11%). Adductor tendinopathy represented only 2.70% of cases.

CONCLUSIONS

Female athletic patients affected by LSGPS show a similar incidence of inguinal and hip pathologies as in male populations. However, these clinical situations do not seem to be associated in women unlike in the male population. This difference is probably due to particular anatomical differences related to gender. For this reason, women affected by LSGPS represent an important subset of patients. Moreover, adductor tendinopathy is probably overrated as an etiopathogenetic source of LSGPS in women.

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.

Laparoscopic management of moderate: Severe endometriosis

OBJECTIVES:

To assess the feasibility of laparoscopic surgery in cases of moderate-severe endometriosis.

MATERIALS AND METHODS:

A prospective study was carried out in a tertiary centre over a period of 2 years. Moderate to severe endometriosis was defined by revised American fertility society (rAFS) classification (41 patients). Various procedures were done to provide symptomatic relief. Feasibility of laparoscopic surgery and various patient parameters were analysed.

RESULTS:

Various procedures like adhesiolysis in POD, excision of endometriomas, resection of endometriotic nodules in the recto-vaginal septum, ureterolysis and total laparoscopic hysterectomy with/ without oophorectomy were done. Majority of patients underwent cystectomy for endometriomas (53.6%) or adhesiolysis with excision of endometriotic nodule (36.5%). Total laparoscopic hysterectomy with or without ooperectomy was done in 31.7% patients. Of the total 9 patients with primary infertility and moderate-severe endometriosis, 5 patients (55.5%) conceived after surgery.

CONCLUSION:

There is good evidence that in experienced hands laparoscopic surgery helps in long-term symptomatic relief, improves pregnancy rates and reduces recurrence of disease with largely avoiding complications.

Dietary therapy: a new strategy for management of chronic pelvic pain

Chronic pelvic pain (CPP) can be identified as a chronic nociceptive, inflammatory and neuropathic pain characterised by spontaneous pain and an exaggerated response to painful and/or innocuous stimuli. This pain condition is extremely debilitating and usually difficult to treat. Currently, the main approaches to treatment include counselling supported by reassuring ultrasound scanning or psychotherapy, attempting to provide reassurance using laparoscopy to exclude serious pelvic pathology, hormonal therapy and neuroablative treatment to interrupt nerve pathways. Dietary supplementation has been suggested as a means to treat chronic medical illnesses that are poorly responsive to prescription drugs or in which therapeutic options are limited, costly or carry a high side-effect profile. A comprehensive search of the PubMed database was performed using the search terms 'chronic pelvic pain', 'oxidative stress', 'antioxidants' and 'dietary therapy'. The systematic review focuses on both randomised and non-randomised controlled trials from 2005 onwards, in which CPP was the end point. Given the complexity and not well-understood aetiology of CPP, its treatment is often unsatisfactory and limited to partial symptom relief. Dietary therapy with antioxidants improves function of the immune system and in fighting free radical damage. Agents with antioxidant activity are able to improve CPP without undesired effects and any important metabolic changes associated with hormonal suppression therapy. In conclusion, dietary therapy with antioxidants could be considered as a new effective strategy in the long term for CPP, and may be better accepted by patients. Further randomised trials with larger series and long-term follow-up to confirm these observations are needed.

Generalized hyperalgesia in women with endometriosis and its resolution following a successful surgery

Although pains of various kinds top the list of complaints from women with endometriosis and are the most debilitating of the disease, little is known about the mechanism/mechanisms of endometriosis-associated pains. To test the hypothesis that women with endometriosis have generalized hyperalgesia which may be alleviated by a successful surgery, we recruited 100 patients with surgically and histologically confirmed endometriosis and 70 women without, and tested their responses to pain stimulations. Before the surgery, all patients rated their dysmenorrhea severity by Visual Analog scale (VAS) and went through an ischemic pain test (IPT) and an electrical pain test (EPT). The controls were also administrated with IPT/EPT. Three and 6 months after surgery, all patients were administrated with IPT/EPT and rated their severity of dysmenorrhea. We found that patients with endometriosis had significantly higher IPT VAS scores and lower EPT pain threshold than controls, but after surgery their IPT scores and EPT pain threshold were significantly and progressively improved, along with their dysmenorrhea severity. Thus, we conclude that women with endometriosis have generalized hyperalgesia, which was alleviated by surgery. Consequently, central sensitization may be a possible mechanism underlying various forms of pain associated with endometriosis, and its recognition should have important implications for the development of novel therapeutics and better clinical management of endometriosis.

Endometriosis and mechanisms of pelvic pain

Endometriosis remains an enigmatic disorder in that the cause, the natural history, and the precise mechanisms by which it causes pain are not completely understood. The pain symptoms most commonly attributed to endometriosis are dysmenorrhea, dyspareunia, and chronic pelvic pain. Pain may be due to nociceptive, inflammatory, or neuropathic mechanisms, and there is evidence that all 3 of these mechanisms are relevant to endometriosis-associated pelvic pain. It is proposed that the clinically observed inconsistencies of the relationships of endometriosis severity and the presence or severity of pain are likely due to variable roles of different pain mechanisms in endometriosis. A better understanding of the roles of nociceptive, inflammatory, and neuropathic pain in endometriosis is likely to improve the treatment of women with endometriosis-associated pelvic pain.

Dysmenorrhea: risk factors in women with endometriosis

Although it is generally accepted that endometriosis is responsible for dysmenorrhea, as well as other symptoms such as infertility, the precise relationship between the severity of dysmenorrhea and various characteristics of disease, such as stage and the type or site of endometriotic lesions, has been elusive and often a matter of heated debate, owing largely to conflicting reports. Here we review factors that are reported to be associated with dysmenorrhea in endometriosis. We also demonstrate, through a real example, that different statistical models employed in data analyses may yield somewhat different sets of risk factors, and the difference may not be always resolved within the same data set. In addition, we make the point that despite the best-fitting models, there may still be a sizable portion of variation in the severity of dysmenorrhea that can not be explained completely by the identified risk factors, suggesting that factors other than those of surgical findings or patient characteristics may also be responsible for dysmenorrhea severity. We review some possible factors that may also be responsible for the risk and severity of dysmenorrhea. Finally, we expose areas in need of further research.

Dyschezia and posterior deep infiltrating endometriosis: analysis of 360 cases

STUDY OBJECTIVE

To evaluate the relationship between anatomic locations and diameter of endometriotic lesions with severity of perimenstrual dyschezia (pain with defecation) as a possible location-indicating pain symptom for posterior deep infiltrating endometriosis (DIE).

DESIGN

Retrospective analysis (Canadian Task Force classification II-3).

SETTING

Tertiary care university hospital.

PATIENTS

We reviewed hospital records of patients who underwent laparoscopic treatment for pelvic endometriosis in our center between 2001 and 2006. In all, 360 patients with posterior DIE (endometrial glands and stroma infiltrated excised tissues of the specified organs) were included for whom preoperative scoring of perimenstrual dyschezia was performed using a 10-point visual analog scale (VAS). Data about anatomic location and diameter of excised nodules were retrieved from operative and pathological records.

INTERVENTIONS

Laparoscopic excision of suspected endometriotic lesions.

MEASUREMENTS AND MAIN RESULTS

Mean VAS score of dyschezia for patients with overall posterior DIE was 3.9 +/- 3.8, whereas in unaffected patients it was 1.9 +/- 3.3 (Mann-Whitney test p <.0005). Rectovaginal involvement (posterior vaginal wall, rectovaginal septum, and anterior rectal wall) was found in 240 of 360 women. Mean VAS score for dyschezia was 4.1 +/- 4 and 2.1 +/- 3.3 in affected and nonaffected patients, respectively (p <.0005). Mean lesion diameter in affected patients was significantly correlated with mean VAS score (Spearman rho = 0.21). Patients with anterior rectal wall endometriosis (71/240) had a mean VAS score of 4.2 +/- 4 and in nonaffected patients it was 2.7 +/- 3.6 (p <.05). Mean lesion diameter in affected patients was not significantly correlated with mean VAS score of dyschezia (Spearman rho = 0.16).

CONCLUSION

Severity of dyschezia was significantly correlated with posterior DIE. A positive correlation occurred between severity of dyschezia and lesion diameter with rectovaginal endometriosis but not with anterior rectal wall involvement.

A pilot study to evaluate the clinical relevance of endometriosis-associated nerve fibers in peritoneal endometriotic lesions

OBJECTIVE

To investigate the clinical relevance of endometriosis-associated nerve fibers in the development of endometriosis-associated symptoms.

DESIGN

Prospective nonrandomized study.

SETTING

University hospital endometriosis center.

PATIENT(S)

Fifty-one premenopausal patients underwent surgical laparoscopy because of chronic pelvic pain, dysmenorrhea, or for ovarian cysts. Endometriosis was diagnosed in 44 patients.

INTERVENTION(S)

The preoperative and postoperative pain scores were determined using a standardized questionnaire with a visual analogue scale from 1-10. Patients with peritoneal endometriosis were divided into two groups depending on their preoperative pain score: group A with a pain score of at least 3 or more and group B with a pain score of 2 or less. Patients without peritoneal endometriosis were classified as group C and patients without endometriosis were classified as group D. Immunohistochemical analysis of neurofilament and protein gene product 9.5 were used for nerve fiber detection. Occurrence of endometriosis-associated nerve fibers was correlated with the severity of pelvic pain and/or dysmenorrhea.

RESULT(S)

Peritoneal endometriosis-associated nerve fibers were found significantly more frequently in group A than in group B (82.6% vs. 33.3%).

CONCLUSION(S)

The present study suggests that the presence of endometriosis-associated nerve fibers in the peritoneum is important for the development of endometriosis-associated pelvic pain and dysmenorrhea.

Relationship between site and size of bladder endometriotic nodules and severity of dysuria

STUDY OBJECTIVE

The purpose of this study was to evaluate the relationship between frequency/severity of dysuria with anatomic location and diameter of bladder endometriotic lesions.

DESIGN

Retrospective analysis (Canadian Task Force classification II-3).

SETTING

Tertiary care university hospital.

PATIENTS

Forty-one patients with bladder endometriosis (endometrial glands and stroma microscopically diagnosed to infiltrate the muscularis propria).

INTERVENTIONS

Laparoscopic partial cystectomy, preoperative scoring of dysuria using 10-point verbal analog scale (VAS).

MEASUREMENTS AND MAIN RESULTS

Records of all patients with bladder endometriosis were assessed for frequency/severity of preoperative dysuria, anatomic location (base or dome), and diameter of bladder endometriotic nodule. Basal bladder lesions were observed in 18 (43.9%) of 41 patients versus 23 (56.1%) of 41 in the dome. Of the patients with basal lesions, 14 (77.8%) of 18 had preoperative dysuria versus 8 (34.8%) of 23 with dome lesions. Mean VAS score was 8.5 +/- 2.37 and 5.75 +/- 1.91 for base and dome lesions, respectively. Preoperative dysuria was found in 22 (53.7%) of 41 patients. Mean lesion diameter in patients with dysuria was 25.0 +/- 12.6 mm versus 16.3 +/- 6.8 mm in patients without dysuria.

CONCLUSION

Frequency and severity of preoperative dysuria were significantly higher in patients with basal endometriotic nodules. There was a positive correlation between severity of dysuria and lesion diameter.

Growth-associated protein 43–positive sensory nerve fibers accompanied by immature vessels are located in or near peritoneal endometriotic lesions

OBJECTIVE

To investigate the topographical relationship between nerve fibers and peritoneal endometriotic lesions and to determine the origin of endometriosis-associated nerve fibers.

DESIGN

Retrospective nonrandomized study.

SETTING

University hospital endometriosis research center.

PATIENT(S)

Premenopausal women with histologically confirmed endometriosis were selected (n = 73). Peritoneal endometriotic lesions (n = 106) and unaffected peritoneal biopsies from patients without endometriosis (n = 9) were obtained.

INTERVENTION(S)

Immunohistochemistry was used to study the expression of neurofilament, substance P, smooth muscle actin, von Willebrand factor, growth-associated protein 43, nerve growth factor, and neutrophin-3 in peritoneal endometriotic lesion samples from women with symptomatic endometriosis and in peritoneal samples from women without endometriosis.

RESULT(S)

Pain-conducting substance-P-positive nerve fibers were found to be directly colocalized with human peritoneal endometriotic lesions in 74.5% of all cases. The endometriosis-associated nerve fibers are accompanied by immature blood vessels within the stroma. Nerve growth factor and neutrophin-3 are expressed by endometriotic cells. Growth-associated protein 43, a marker of neural outgrowth and regeneration, is expressed in endometriosis-associated nerve fibers but not in existing peritoneal nerves.

CONCLUSION(S)

The data provide the first evidence of direct contact between sensory nerve fibers and peritoneal endometriotic lesions. This implies that the fibers play an important role in the etiology of endometriosis-associated pelvic pain. Moreover, emerging evidence suggests that peritoneal endometriotic cells exhibit neurotrophic properties.

The levonorgestrel-releasing intrauterine system and endometriosis staging

This study aims to determine whether the levonorgestrel-releasing intrauterine system can influence American Society for Reproductive Medicine endometriosis staging scores, as assessed through second-look laparoscopies, and to compare the results with those obtained with a GnRH agonist. Both treatments reduced the extent of pelvic endometriotic lesions in patients with chronic pelvic pain.

Villar's nodule: a case report and systematic literature review of endometriosis externa of the umbilicus

We report a case of umbilical endometriosis externa and systematically review the literature regarding this finding. In our case report, a 47-year-old woman with cyclic umbilical bleeding, pelvic pain, and no previous umbilical surgery developed a spontaneous umbilical endometrioma, cured by surgical resection and bilateral salpingo-oophorectomy. In our review, 122 patients with documented umbilical endometriomas from 1966 to the present and 109 cases reported before 1953 were analyzed. Procedures used for diagnosis and/or therapeutic intervention included umbilical biopsy or resection, abdominal wall repair, diagnostic and/or operative laparoscopy, adhesiolysis, hysterectomy, and bilateral salpingo-oophorectomy. Variables included patient age; race; medical and surgical history; past use of oral contraceptives; history of umbilical pain, bleeding, or swelling; duration of signs and symptoms; size and color of the lesion; diagnostic evaluations; and medical or surgical management. Mean age of the study population was 37.7 +/- 0.98 years. Up to 40% of patients with extrapelvic endometriosis present with umbilical endometriomas, with symptoms occurring an average of 17.8 +/- 3.9 months before presentation. Lesions averaged 2.3 +/- 0.2 cm in diameter; were predominantly brown (19.1%), blue (13.2%), or purple (10.3%); and patients frequently had with pain (77.93%), cyclical bleeding (47.1%), and swelling (88.2%). Most patients had no history of endometriosis (73.1%), and laparoscopic, umbilical trocar-related seeding was identified in only 5 patients. Three patients received medical management, and surgical management was invariably curative, though 1 patient required repeat surgical therapy. Umbilical endometriosis is a common manifestation of external endometriosis, representing primary or secondary endometriosis, with a typical presentation that has little variation. Laparoscopic endometrioid tissue excision can result in iatrogenic seeding to the umbilicus. Historical and physical findings are pathognomonic, thus justifying a formal name--Villar's nodule, after the initial reporting physician. Surgical intervention is recommended, but medical therapy may result in long-term symptom control with minimal malignancy risk.

Association between endometriosis stage, lesion type, patient characteristics and severity of pelvic pain symptoms: a multivariate analysis of over 1000 patients

BACKGROUND

The association between lesion type, disease stage and severity of pain was studied in a large group of women with endometriosis to verify whether endometrial implants at different sites determine specific complaints and to evaluate the validity of the current classification system in women with symptomatic disease.

METHODS

A total of 1054 consecutive women with endometriosis undergoing first-line conservative or definitive surgery were included. Data on age at surgery, disease stage according to the revised American Fertility Society (AFS) classification, anatomical characteristics of endometriotic lesions, and type and severity of pain symptoms were collected and analysed by multiple logistic regression.

RESULTS

Minimal endometriosis was present in 319 patients, mild in 139, moderate in 292 and severe in 304. A significant inverse relationship was demonstrated between age at surgery and moderate-to-severe dysmenorrhoea, dyspareunia and non-menstrual pain. A strong association was found between posterior cul-de-sac lesions and pain at intercourse [Wald chi (2) = 17.00, P = 0.0001; odds ratio (OR) = 2.64, 95% confidence interval (CI) = 1.68-4.24]. A correlation between endometriosis stage and severity of symptoms was observed only for dysmenorrhoea (Wald chi (2) = 5.14, P = 0.02) and non-menstrual pain (Wald chi (2) = 5.63, P = 0.018). However, the point estimates of ORs were very close to unity (respectively, 1.33, 95% CI = 1.04-1.71, and 1.01, 95% CI = 1.00-1.03).

CONCLUSIONS

The association between endometriosis stage and severity of pelvic symptoms was marginal and inconsistent and could be demonstrated only with a major increase in study power.

HOXA10 expression in ectopic endometrial tissue

OBJECTIVE

To evaluate HOXA10 expression in endometriosis.

DESIGN

Laboratory study using human tissue.

SETTING

Academic research center.

PATIENT(S)

Eutopic endometrial tissue was collected from 20 fertile women without endometriosis. Ectopic endometrial tissues from pelvic peritoneum, ovary, and lung parenchyma were collected from 20 women undergoing surgery for endometriosis.

INTERVENTION(S)

HOXA10 protein expression and localization with immunohistochemistry.

MAIN OUTCOME MEASURE(S)

Quantitative analysis of HOXA10 expression, according to H score.

RESULT(S)

Both eutopic and ectopic endometrial tissue expressed HOXA10. Ectopic endometrial tissue had lower stromal HOXA10 expression compared with eutopic endometrium. The mean H score for stromal expression of HOXA10 was 7.6 in eutopic endometrium and 1.3 in ectopic endometrial tissue. Glandular epithelium from both eutopic and ectopic endometrium had similarly low HOXA10 expression. HOXA10 was also expressed at low levels in lung parenchyma containing endometriosis and in ovarian endometriomas.

CONCLUSION(S)

HOXA10 is expressed in endometriosis at locations outside of the normal HOXA10 expression domain, where it is likely necessary to impart endometrial developmental identity on endometriosis. HOXA10 might be necessary for "de novo" endometrial development. However, the diminished expression of HOXA10 in ectopic endometrium might not allow for normal endometrial development and might contribute to the pathogenesis of endometriosis by creating P resistance.