What is the controversy surrounding the existence of myofascial trigger points (MTPs)?

From the Guidelines

The controversy surrounding trigger points centers on the lack of scientific consensus about their existence and nature, with recent guidelines suggesting that cognitive behavioral therapy, supervised postural exercise, supervised jaw exercise and stretching with or without manual trigger point therapy, and usual care provide important relief of chronic pain associated with temporomandibular disorders (TMD) 1. Trigger points are described as hyperirritable spots in skeletal muscle that are associated with palpable nodules and can cause pain when compressed. However, there is significant debate in the medical community because trigger points cannot be consistently identified through imaging techniques or objective diagnostic tests. Some key points to consider include:

• Critics argue that the concept lacks standardized diagnostic criteria and that studies supporting trigger point therapy often have methodological flaws.
• Some researchers suggest that perceived trigger points may actually represent referred pain patterns or normal anatomical variations rather than distinct pathological entities.
• The proposed mechanisms behind trigger points, such as the "energy crisis theory" involving localized muscle contractions and metabolic abnormalities, remain theoretical without conclusive evidence.
• Recent guidelines, such as those published in 2023, provide moderate to high certainty evidence for the effectiveness of cognitive behavioral therapy, supervised postural exercise, supervised jaw exercise and stretching with or without manual trigger point therapy, and usual care in reducing chronic pain severity associated with TMD 1.
• The panel was confident that these treatments provide important relief of chronic pain associated with TMD, approximating to 1.5× the minimally important difference (MID).
• However, the panel was less confident about the effectiveness of other treatments, such as invasive procedures like arthrocentesis and trigger point injections, which may result in moderate harm. Overall, the current evidence suggests that a multimodal approach, including cognitive behavioral therapy, supervised exercise, and manual trigger point therapy, may be effective in reducing chronic pain associated with TMD, but more research is needed to fully understand the nature and treatment of trigger points 1.

From the Research

Controversy Surrounding Myofascial Trigger Points (MTPs)

The existence of myofascial trigger points (MTPs) is a topic of controversy, with some studies supporting their existence and others questioning their validity.

• The concept of MTPs is based on the idea that trigger points are taut, band-like nodules within skeletal muscle that can produce pain and disability 2.
• However, some researchers have critically evaluated the evidence for the existence of MTPs and found that it lacks scientific basis 3.
• Studies have shown that treatments such as massage, physical therapy, and osteopathic manual medicine can be effective in managing myofascial pain, but the role of MTPs in this process is unclear 2, 4, 5.
• Some researchers have suggested that the theory of MTPs is an invention with no scientific basis, and that the clinical phenomena associated with MTPs can be explained by known neurophysiological phenomena 3.
• Other studies have compared the effectiveness of different treatments for MTPs, including lidocaine injection, botulinum toxin injection, and dry needling, but the results are inconsistent and do not provide clear evidence for the existence of MTPs 4, 6.

Key Findings

• A study published in the American Family Physician found that trigger point injections can be effective in managing myofascial pain, but the conclusions are limited by methodological flaws 2.
• A study published in Rheumatology International found that lidocaine injection, botulinum toxin injection, and dry needling can all be effective in reducing pain and improving function in patients with myofascial pain syndrome, but the results do not provide clear evidence for the existence of MTPs 4.
• A study published in the Journal of Pain & Palliative Care Pharmacotherapy reviewed the pathophysiology of trigger points in myofascial pain syndrome, but did not provide conclusive evidence for the existence of MTPs 5.
• A study published in Rheumatology found that the theory of MTPs lacks scientific basis and that the clinical phenomena associated with MTPs can be explained by known neurophysiological phenomena 3.
• A study published in Cranio found that botulinum toxin, lidocaine, and dry-needling injections can all be effective in reducing pain and improving function in patients with myofascial pain and headaches, but the results do not provide clear evidence for the existence of MTPs 6.