What are trigger point injections used for and how are they administered?

Trigger Point Injections: Clinical Use and Administration

Trigger point injections should be reserved for patients with myofascial pain who have failed conservative treatments (physical therapy, massage, exercise), as they provide only short-term symptomatic relief without demonstrated long-term benefit. 1, 2, 3

What Are Trigger Point Injections Used For?

Trigger point injections target hyperirritable spots within taut bands of skeletal muscle that produce localized and referred pain, motor dysfunction, and autonomic symptoms. 4 The primary indication is myofascial pain syndrome that has been refractory to less invasive measures. 3

Evidence-Based Indications:

• Temporomandibular disorders (TMD): Manual trigger point therapy provides approximately twice the minimally important difference in pain reduction compared to placebo (moderate certainty evidence). 5
• Trapezius muscle pain: TPIs are recommended only for temporary symptomatic relief in selected patients, as long-lasting benefit has not been demonstrated. 1
• NOT recommended for: Chronic low back pain without radiculopathy, as there is insufficient evidence for long-term benefit. 5, 2

Treatment Hierarchy:

First-line approaches (try these before injections): 3

• Massage therapy
• Physical therapy with stretching and strengthening exercises 1
• Osteopathic manual medicine
• Conservative medication management

Second-line approach (when conservative measures fail): 1, 3

• Trigger point injections for temporary relief only

How Are They Administered?

Injection Technique:

Standard approach: 6, 4

• Local anesthetic (typically lidocaine) infiltrated directly into the trigger point
• No single pharmacologic agent has proven superior to another or to placebo 3
• Dry needling may be equally effective as injections containing medications 1

Special considerations for obese patients or cervicothoracic region: 7, 8

• Electromyographically-guided injections using EMG to confirm needle placement within muscle tissue (not adipose)
• Ultrasound-guided injections allow real-time visualization and reduce pneumothorax risk
• These guidance techniques are particularly important in the cervicothoracic spine where misplaced injections can cause pneumothorax

Alternative delivery method: 9

• Jet injection systems produce significantly less pain during treatment than conventional needle injections
• Provide equivalent short-term pain relief to conventional trigger point injections

Frequency and Duration Limits:

Critical restrictions to avoid harm: 1

• Once therapeutic effect is achieved, do NOT repeat more frequently than once every 2 months
• Maximum of 4 sets of injections to diagnose pain origin and achieve therapeutic effect
• Additional injections are NOT medically necessary if no clinical response achieved from previous injections
• Document quantifiable improvement in pain scores, function, and duration of relief before any repeat injection

Common Pitfalls to Avoid:

• Performing repeated injections without documented improvement: You must quantify pain scores, functional improvement, and duration of relief before repeating. 1
• Using TPIs as long-term pain management: They provide only short-term relief and should not be the primary treatment strategy. 1, 2, 3
• Injecting without trying conservative measures first: Physical therapy, exercise, and manual therapy should precede injections. 1, 3
• Continuing injections despite lack of response: If no improvement after initial sets, discontinue and consider alternative approaches. 1
• Using TPIs as standalone treatment: They must be part of a comprehensive, multimodal, team-based approach to myofascial pain. 2, 3

When to Escalate Care:

If conservative measures and injection therapies fail to provide adequate relief after 2-3 months, surgical evaluation may be considered. 1