What is Myofascial Pain Syndrome (MPS)?

What is Myofascial Pain Syndrome?

Myofascial Pain Syndrome (MPS) is a chronic regional musculoskeletal pain disorder characterized by hyperirritable trigger points within taut bands of skeletal muscle fibers that produce both localized and referred pain when palpated. 1, 2

Clinical Characteristics

MPS presents with distinct features that differentiate it from other chronic pain conditions:

• Trigger points are the hallmark finding—discrete, hyperirritable spots within taut muscle bands that reproduce the patient's pain pattern upon palpation 1, 3
• Referred pain patterns occur when trigger point palpation produces pain away from the site in characteristic distributions 2, 3
• Local twitch response may be elicited when the trigger point is stimulated by needle or palpation 3
• Regional distribution distinguishes MPS from fibromyalgia, which presents with diffuse, widespread pain rather than localized tender areas 2

The prevalence among patients presenting to medical clinics with pain ranges from 30% to 93%, though this wide variation reflects the lack of standardized diagnostic criteria 3. Up to 85% of adults experience MPS during their lifetime 4.

Pathophysiology and Risk Factors

The exact pathogenesis remains incompletely understood, but several contributing factors have been identified 1, 3:

• Muscle overuse or underuse with sustained muscle contraction is thought to be the primary mechanism 2
• Postural imbalances contribute to chronic muscle strain 1
• Systemic conditions including bladder pain syndrome, endometriosis, and anxiety are associated with increased MPS prevalence 4
• Psychological and behavioral factors play a role in onset and persistence 1

Diagnostic Approach

Physical examination remains the cornerstone of diagnosis, as there are no universally accepted diagnostic criteria or laboratory tests for MPS. 2, 3

Essential examination findings include:

• At least one localized trigger point that recreates the patient's pain when palpated 2
• Pain upon palpation of the trigger point 3
• Referred pain pattern characteristic of the affected muscle 3
• Pelvic floor tenderness should be assessed when appropriate, as many patients exhibit tenderness and banding of pelvic floor musculature 5

A critical pitfall is confusing MPS with fibromyalgia—MPS involves localized pain with discrete tender areas, while fibromyalgia presents with diffuse, widespread symptoms 2. MPS commonly coexists with other chronic pain conditions, requiring careful evaluation 2, 4.

Management Strategy

A multimodal approach is recommended, combining patient education, exercise, behavior modification, pharmacotherapy, and procedural interventions, with early intervention being crucial as chronic MPS becomes increasingly refractory to treatment. 2, 6

First-Line Interventions

Manual physical therapy techniques should be offered when pelvic floor or muscular trigger points are present, including maneuvers that resolve trigger points, lengthen muscle contractures, and release connective tissue restrictions 5. A randomized controlled trial demonstrated that 59% of patients receiving myofascial physical therapy reported moderate or marked improvement at 3 months compared to 26% receiving global therapeutic massage 5.

Low-resistance exercise is recommended to improve joint stability by increasing muscle tone, with physical therapy for myofascial release often necessary to facilitate participation 5.

Pharmacologic Options

Evidence for pharmacologic interventions is limited:

• Local anesthetic injections have sufficient evidence supporting their use for MPS 1
• Topical analgesics, NSAIDs, and muscle relaxants are commonly used in clinical practice 2, 6
• Botulinum toxin should not be used in routine care of patients with myofascial pain, as randomized controlled trials show equivocal findings 5
• Antidepressants, gabapentin, opioids, and topical agents (lidocaine, capsaicin) have inconclusive evidence 1

Procedural Interventions

Several interventions show promise, though evidence quality varies:

• Dry needling and acupuncture may be effective compared to sham or placebo 5, 1
• Trigger point injections are a standard treatment modality 6
• Extracorporeal shockwave therapy, laser therapy, and ultrasound therapy show some evidence of effectiveness 1
• Transcutaneous electrical nerve stimulation (TENS) should be used as part of a multimodal approach for chronic pain conditions 5
• Magnetic stimulation and manual therapy may provide benefit 1

Ultrasound guidance has emerged as a key tool for precise, minimally invasive treatment delivery, particularly for interfascial hydrodissection and trigger point injections 7.

Interventions to Avoid

Pelvic floor strengthening exercises (e.g., Kegel exercises) should be avoided when pelvic floor tenderness is present 5. This represents a common pitfall, as strengthening already tense muscles can worsen symptoms.

Prognosis

Symptoms often resolve with early multimodal intervention, but as MPS enters the chronic stage, it becomes increasingly refractory to treatment 2. This underscores the importance of early recognition and aggressive management to prevent chronicity.