What is the role of trigger point injections in managing chronic pain?

From the Guidelines

Trigger point injections are not recommended as a first-line treatment for managing chronic pain associated with temporomandibular disorders (TMD) due to the possibility of moderate harm and limited evidence of their effectiveness compared to other available treatments. According to the most recent and highest quality study published in the BMJ in 2023 1, the guideline panel issued conditional recommendations against trigger point injections, citing the potential for moderate harm, such as local infection.

The study found that cognitive behavioral therapy (CBT) augmented with relaxation therapy or biofeedback, therapist-assisted jaw mobilisation, and manual trigger point therapy provide the largest reduction in chronic pain severity associated with TMD, approximating twice the minimally important difference (MID) 1. In contrast, trigger point injections were associated with a higher risk of harm and were not recommended as a primary treatment option.

Some of the key points to consider when evaluating the role of trigger point injections in managing chronic pain include:

• The potential benefits of trigger point injections, such as reducing inflammation and relaxing tense muscle fibers, are outweighed by the risks of moderate harm, including local infection 1.
• Other treatment options, such as CBT, manual trigger point therapy, and supervised postural exercise, have been shown to be more effective in reducing chronic pain severity associated with TMD 1.
• The use of trigger point injections should be carefully considered on a case-by-case basis, taking into account the individual patient's needs and medical history.
• Patients should be informed of the potential risks and benefits of trigger point injections and alternative treatment options should be explored before proceeding with injections.

Overall, while trigger point injections may be useful in certain situations, the current evidence suggests that they should not be recommended as a first-line treatment for managing chronic pain associated with TMD due to the potential for harm and limited evidence of their effectiveness compared to other available treatments 1.

From the Research

Trigger Point Injections for Chronic Pain Management

• Trigger point injections are a treatment option for managing chronic pain, particularly for myofascial pain syndromes 2, 3.
• The injections can be performed with or without imaging guidance, and various substances can be used, including local anesthetics, botulinum toxin, or corticosteroids 2.
• Some studies suggest that trigger point injections can provide significant symptom relief for patients with chronic abdominal pain attributed to abdominal wall pain 4.

Efficacy of Trigger Point Injections

• Research has shown that trigger point injections can be effective in reducing pain, with some studies demonstrating statistically significant results 5, 3.
• However, the conclusions are limited by factors such as low study participant numbers, difficulty in blinding, and potential placebo effects 3.
• No single pharmacologic agent used in trigger point injections has been proven superior to another, nor has any single agent been proven superior to placebo 3.

Safety and Adverse Events

• Corticosteroid injections, which are sometimes used in trigger point injections, can have adverse events such as increased blood glucose, decreased bone mineral density, and suppression of the hypothalamic-pituitary axis 6.
• The use of imaging guidance, such as ultrasound or fluoroscopy, can improve the safety of trigger point injections by reducing the risk of adverse events 2, 6.
• The American Society of Regional Anesthesia and Pain Medicine and other societies have developed guidelines for the use of corticosteroids in trigger point injections, recommending careful consideration of the potential benefits and risks 6.

Patient Selection and Response

• Trigger point injections should be reserved for patients whose myofascial pain has been refractory to other measures, and less invasive treatment strategies should be employed first 3.
• Patient characteristics, such as somatization, can negatively predict response to trigger point injections, and other historical, examination, or injection characteristics may not be associated with response 4.