What is the role of trigger point (TP) injections in treating lumbar back pain?

Trigger Point Injections for Lumbar Back Pain

Direct Recommendation

Trigger point injections with lidocaine (0.5%) provide short-term symptomatic relief for selected patients with lumbar myofascial pain, but should be limited to a maximum of 4 treatment sessions over 8 months, with mandatory documentation of quantifiable improvement between sessions. 1

Evidence Quality and Clinical Reality

The evidence supporting trigger point injections for lumbar back pain is limited to Class II and III studies with small populations and short follow-up periods. 1 However, the available data demonstrates that:

• Lidocaine injections are superior to saline placebo for short-term pain relief (52% vs 30% improvement at 2 weeks, p=0.05) 2, 1
• Pain relief typically lasts 2 weeks to 2 months per injection, with maximum benefit in the first week 1
• Dry needling alone may be equally effective as medication injection (63% vs 42% pain reduction, p=0.09), suggesting the mechanical needle stimulation itself provides therapeutic benefit 2, 1, 3

Treatment Protocol

Patient Selection

• Identify patients with documented myofascial trigger points on examination: focal tenderness on palpation, restricted stretch range of motion, and local twitch response on needle stimulation 2
• Ensure conservative measures have been attempted first (NSAIDs, physical therapy, therapeutic exercise) 1
• Radiculopathy is a contraindication for facet-mediated pain, though trigger points may coexist with radicular symptoms 1

Injection Technique

• Use 0.5% lidocaine at identified trigger points in lumbar paraspinal muscles 1
• Adding steroids to lidocaine does not improve outcomes beyond lidocaine alone 2, 1
• Consider dry needling as an alternative, which avoids medication-related risks while providing similar efficacy 1, 3

Frequency Limitations

• Maximum of 4 injection sessions to establish therapeutic response and diagnose pain origin 1
• Do not repeat more frequently than once every 2 months if therapeutic effect is achieved 4, 1
• Only repeat if there was documented quantifiable improvement from the previous injection 1

Mandatory Documentation Requirements

Document the following after each injection session:

• Baseline pain scores (VAS or similar validated measure) 1
• Functional status changes 1
• Duration of relief achieved 1

Injections should NOT be repeated without documented quantifiable improvement - this represents inappropriate care and lacks medical necessity. 1

Concurrent Physical Therapy is Essential

• Physical therapy focusing on stretching and strengthening exercises should be the primary approach, with trigger point injections serving as an adjunct to facilitate participation in active rehabilitation 1
• Injections should never replace physical therapy - they are temporary symptomatic treatments only 1
• According to Simons and Travell, trigger point injection can result in long-term relief only if mechanical and systemic perpetuating factors are corrected 2

Critical Pitfalls to Avoid

• Performing repeated injections without documented improvement - this is inappropriate care 1
• Using trigger point injections as long-term pain management - these are temporary symptomatic treatments only 1
• Failing to implement concurrent physical therapy - injections should facilitate rehabilitation, not replace it 1
• Continuing the same intervention despite lack of significant improvement 4

When to Consider Alternative Approaches

• If no clinical response after 4 injection sessions, additional injections are not medically necessary 4
• If conservative measures and injection therapies fail after 2-3 months, surgical evaluation may be considered 4
• Consider dry needling as a first-line mechanical intervention, which may be as effective as medication injection 1, 3

Special Considerations

Recent research suggests that intraosseous trigger point injections may be more effective than intramuscular injections (92% more effective), particularly when administered in the posterior superior iliac spine region 5. However, this technique requires specialized training and is not yet incorporated into standard guidelines.