This study will evaluate the clinical and biological effects of acupuncture for chronic low back pain associated with myofascial pain syndrome (MPS).

In this randomized, participant- and assessor-blinded clinical trial, 64 adults with chronic low back pain due to MPS will be assigned to receive either true acupuncture or sham acupuncture for eight weeks. Participants will undergo total-body positron emission tomography/computed tomography (TB-PET/CT) imaging and complete standardized pain and functional questionnaires at baseline and after treatment.

The study will evaluate whether acupuncture improves pain and function compared with sham treatment and whether TB-PET/CT imaging can detect changes in myofascial tissue metabolism and perfusion that correspond with clinical outcomes.

Myofascial pain syndrome (MPS) is a musculoskeletal pain disorder characterized by localized muscle pain, trigger points, and functional limitations. MPS is frequently associated with chronic low back pain and contributes substantially to reduced quality of life and increased healthcare utilization. Despite its prevalence, diagnosis and treatment monitoring rely largely on subjective clinical examination and patient-reported outcomes because validated objective biomarkers of myofascial tissue dysfunction are lacking.

Acupuncture is widely used as a non-pharmacologic treatment for chronic pain and has demonstrated benefit in several chronic low back pain studies. However, the biological mechanisms underlying acupuncture's therapeutic effects remain poorly understood, in part because objective measures of tissue-level response are limited.

Total-body positron emission tomography/computed tomography (TB-PET/CT) is a highly sensitive molecular imaging technique capable of assessing metabolic activity and blood flow throughout the body. Recent observational work using TB-PET/CT has demonstrated the ability to differentiate painful myofascial tissue from non-painful tissue, suggesting that this technology may provide quantitative biomarkers of myofascial dysfunction.

The IMPACT-MPS study is a two-arm, randomized, participant- and assessor-blinded, sham-controlled clinical trial designed to evaluate both the clinical efficacy of acupuncture and the utility of TB-PET/CT imaging biomarkers in MPS. A total of 64 adults with chronic low back pain associated with myofascial pain syndrome will be enrolled and randomized in a 1:1 ratio to receive either standardized acupuncture treatment or sham acupuncture.

Participants will receive up to three acupuncture or sham sessions per week for eight weeks. TB-PET/CT imaging and patient-reported outcome assessments will be performed at baseline and at 8 weeks, with an optional imaging and assessment visit at week 4. Clinical outcomes will include standardized pain and function measures, including the PEG (Pain intensity, Enjoyment of life, General activity) scale and other NIH HEAL Common Data Elements.

The primary clinical endpoint is the change in PEG score from baseline to 8 weeks. The primary imaging endpoint is the change in standardized uptake values in predefined myofascial regions of interest measured by TB-PET/CT. Secondary outcomes include additional patient-reported outcomes and imaging measures of myofascial tissue metabolism and perfusion.

This study aims to determine whether acupuncture improves clinical outcomes in patients with myofascial pain syndrome and to evaluate TB-PET/CT as an objective imaging biomarker of myofascial tissue dysfunction and treatment response. The results may support the development of imaging-based tools for evaluating chronic musculoskeletal pain and monitoring treatment effects.

Inclusion Criteria:

• Ability to understand the purposes and risks of the trial and willingness to sign an informed consent form
• Willingness and ability to comply with all protocol required procedures
• Willingness to be randomized to receive either true acupuncture or sham acupuncture
• Current self-report of chronic low back pain (cLBP) which has persisted for the past 3 months AND has resulted in pain on > 50% of days in the past 6 months
• At least one palpable nodule or taut band in paraspinal, quadratus lumborum, or gluteal muscles
• Reproduction of the patient's dominant pain with palpation of a muscle nodule or taut band
• Predominantly paramedian pain (may be uni-lateral or bi-lateral)
• Willing and able to lay motionless in a supine position at least twice, preferably thrice: 70-minute TB-PET/CT scan
• Willing and able to fast for at least 6 hours before and for the duration of the TB-PET/CT scan
• Willing to avoid strenuous exercise for 24 hours before the TB-PET/CT scan visit
• Willingness to practice effective contraception during the study.

Exclusion Criteria:

• No Primary Care Physician
• History of spine infection (discitis or osteomyelitis) or spine tumor
• History of ankylosing spondylitis, rheumatoid arthritis, polymyalgia rheumatica, psoriatic arthritis, or lupus
• Confounding conditions that are known to be responsible for inducing pain
• Implants at or in the region of the sites of interest
• Diagnosis of any vertebral fracture in the last 6 months
• Cauda equina syndrome or lumbar radiculopathy with functional motor deficit (strength<4/5 on manual motor testing)
• Spinal implants (including fixation hardware, spinal cord stimulator, intra-thecal pumps, that are present in the region of the sites of interest)
• Predominantly central pain
• Pain below the knee
• Positive straight leg raise test
• Symptomatic hip arthritis
• Uncontrolled claustrophobia
• Pregnant or lactating participants
• Body weight more than 225 kg (496 pounds) due to the weight limitation of the scanner bed
• Prisoners
• Inability to speak, read, and write in the English language
• Concurrent or prior enrollment in a separate research study involving a PET scan performed within the last 12 months for research purposes only.

That is, PET scans are not performed as part of a patient's treatment plan (e.g. standard of care, therapeutic purposes, or clinical care) and the research study did not intend to provide therapeutic benefit to the patient.

•Any other criteria, which would make the participant unsuitable to participate in this study as determined by the Principal Investigator