NIRS for the Diagnosis of Myofascial Pelvic Pain

DETAILED DESCRIPTION Introduction. Myofascial pelvic pain (MPP) is the predominant underlying cause in 60-90% of women with chronic pelvic pain. MPP can be debilitating, and is often associated with bladder, bowel, and sexual dysfunction. MPP can be debilitating, leading to social withdrawal, loss of productivity, impaired relationships, and psychological comorbidities. Despite the high prevalence, myofascial pain is often overlooked by first-line healthcare providers; most providers, including gynecologic and urologic specialists, lack the knowledge or experience to even identify MPP. Unfortunately, there are currently no widely accepted measures to quantify muscular fitness or dynamic function of the pelvic floor. Improved recognition of MPP needs objective, reproducible, and quantifiable assessments of PFM fitness, to differentiate between forms of myofascial dysfunction and correlate those patterns with different symptoms. Improved recognition of MPP needs objective, reproducible, and quantifiable assessments of PFM fitness, to facilitate improvements in the recognition and diagnosis of MPP.

Objective: This trial will use optical technology (near infrared spectroscopy) to provide novel imaging and physiologic measures relevant to the PFM for the diagnostic evaluation of MPP.

Primary Purpose: Diagnostics Subject Recruitment: Healthy controls, who must lack pelvic pain, bowel disturbances, urinary symptoms, or sexual dysfunction, will be recruited from the community through online and targeted advertisements in gynecology and primary clinics. IRB approval for these studies is already in place, and we have already begun recruitment of control volunteers. Subjects with MPP, defined by pelvic floor myofascial pain in the absence of other identifiable pain generators, will be recruited from the UCLA Center for Women's Pelvic Health.24 MPP subjects meeting inclusion/exclusion criteria will be approached for enrollment prior to treatment assignment. Baseline demographics and clinical data, including age, height, weight, comorbidities, past surgeries, and medications, including hormones, will be self-reported at enrollment through a questionnaire on REDCap.

Vaginal NIRS-based Pelvic Floor Assessment: An 8-channel, multipoint vaginal NIRS interface miniaturized into a tampon-sized instrument, capable of measuring regional changes in pelvic floor muscle oxygenation in different quadrants and muscle depths, will assess oxygenation and hemodynamic parameters in the pelvic floor muscles. The NIRS sensor, housed in a sterile, single use, disposable child size speculum and placed within a sterile cover, will be inserted in the vagina. The participant will then complete two rounds of the same standardized series of contractions: a series of three maximal voluntary contractions (MVC) and one sustained contraction (SMVC). After each contraction series, there will be a 2-minute recovery period.

Statistical Analysis. Individual NIRS parameters for MPP subjects will be compared to controls by independent sample t-test or Wilcoxon signed-rank test. To generate a predictive model for MPP diagnosis, we will use Least Angle Shrinkage and Selection Operator (LASSO) to identify candidate predictors from individual NIRS features using ten-fold cross-validation. From potential predictors (i.e., non-zero coefficients), we will select features with standardized shrunken coefficients >0.4 to be used in a multivariable logistic regression model. Only statistically significant model coefficients will be retained to provide a reduced predictive model, whose performance will be evaluated by area under the receiver operating curve (AUROC). AUROC values >0.7 will be demonstrative of an acceptable diagnostic test. We will also report the sensitivity, specificity, and accuracy of the model to quantify anticipated impact.

Outcome: NIRS-based algorithm for the diagnosis of MPP. Impact: The R61 phase will validate vaginal NIRS as an effective, non-invasive, and scalable method to assess pelvic floor muscle fitness, correlating well with current measures of PFM strength and distinguishing the myofascial dysfunction associated with MPP from healthy controls.

Masking: None Allocation: Non-randomized