The Mechanisms Underlying Endometriosis Pain

Washington University School of Medicine

Summary

Aim 1. To determine the factors contributing to pain in patients with chronic pelvic pain with and without endometriosis Aim 2. To determine the changes following endometriosis lesion removal surgery in pain and sex hormone levels. Aim 3. To identify factors predicting clinical pain reduction after lesion removal surgery. Additional exploratory aims might compare subgroups of patients such as patients with vs. without endometriosis, with vs. without additional chronic pain syndromes, and with vs. without hormonal treatment. In addition, the role of lesion-specific immune signatures and psychological factors on pain will be explored. Patients with pelvic pain potentially due to endometriosis will complete questionnaires including social, health, behavioral, and psychological questionnaires. Patients will also complete a 2.5 hours study visit of psychophysical assessments of thermal and pressure stimuli. In addition, blood, urine, and saliva samples will be collected for hormonal, immune, and genetic analyses. Additional samples might be collected and stored for future analyses. For some participants, these procedures will be completed several times, including before the surgery as well as 3 months, 6 months and 1 year after surgery. After the surgery, surveys assessing pain and other symptoms will be sent every week on the first month and then monthly for 1 year. In addition, during the surgery, biopsies will be collected and analyzed to determine hormonal, immune and genetic factors. For adolescents, a parent/legal guardian will be asked to assist in completing some of the health-related surveys (i.e., physical developmental survey, health survey, migraine history survey).

Description

Pre-Study Period Participants will be recruited via the pain and Ob/Gyn clinics and via EPIC. Potential participants might be identified via EPIC records using age, sex, diagnoses, notes, problem list, medications, date of scheduled surgery, name of physician performing the surgery, and phone number. A research staff member will contact a potential participant and provide a description of the project. Potentially eligible participants will be invited to participate in the study, which will be conducted at Washington University School of Medicine. Participants will also be provided with a wri…

Interventions

Other

Psychophysical assessment

Thermal stimuli: The Thermal Sensory Analyzer will be used to deliver heat and cold stimuli. All targeted stimulus temperatures will be less than 50°C, and participants will be free to remove their arm or leg at any time from the thermode. Noxious cold stimuli will also be delivered with a plastic water bath or an electronic electronic temperature-controlled water bath. Participants will be free to pull out of the water bath at any time. Pressure stimuli: Pressure stimuli will be applied by using a handheld algometer. These devices have a round probe that allows quantifying the amount of pressure that is being applied by real-time visual feedback to control and monitor applied pressure rates. Pressure will be applied to the lower leg, volar forearm, or trapezius. Mechanical stimuli: A set of standardised von Frey filaments (0.25, 0.5, 1, 2, 4, 8, 16, 32, 64, 128 and 256mN). The contact area of the hairs with the skin is of uniform size (\<1 mm²) and texture.

Behavioral

Psychophysical assessments of experimental pain

Pain ratings- Pain intensity and pain unpleasantness ratings will be assessed Pain thresholds to heat, cold and/or pressure will be tested and participants will be instructed to press a button the first moment they feel pain. Temporal summation- participants will rate the pain evoked by a single pinprick stimulus and by a series of 10 identical pinprick stimuli. Conditioned pain modulation (CPM) efficiency - CPM testing includes the application of a "test" stimulus without conditioning (heat or pressure stimuli) and a subsequent application of the same test stimulus together with a conditioning stimulus (cold stimulus). Offset analgesia will be assessed using the three-temperature method (T1°C 5s, T1+1°C 5s, T1°C 20s). During the OA paradigm, real time pain intensity ratings will be obtained Cold pain tolerance will be assessed by having participants immerse their hand or foot in a cold water bath. Tolerance will be defined by the time of hand/foot withdrawal.

Diagnostic Test

Blood, urine and saliva samples

Blood (approximately 2 tablespoons), urine and saliva samples will be collected and sent to ZRT Laboratory, LabCorp, or internal Washington University lab for analyses of sex hormone levels (e.g., testosterone, estradiol, progesterone). Additional samples will be stored in a biobank for future processing.

Procedure

Biopsy and surgery-related data.

During the surgery, biopsies will be collected from the endometriosis lesions as well as from a healthy peritoneum. If there are no endometriosis lesions, biopsies will be taken of two common locations where endometriosis lesion grows (the infra-ovarian fossa). The lesions will be characterized based on their appearance and invasiveness of the lesions (i.e., powder-burn lesions, nonclassical red or white lesions, and superficially or deeply infiltrating (\>5mm) lesions). In addition, surgery-related data such as the incision size, type of anesthesia, pain ratings after the surgery, analgesic medication after the surgery, and side effects will be documented. Blood, saliva, urine, and samples will be collected for hormonal analyses or stored in a Biobank for future analyses.

The Mechanisms Underlying Endometriosis Pain

Summary

Description

Eligibility

Interventions

Location