Focused Versus Multi-Target Trigger Point Injection for Chronic Myofascial Neck Pain

Myofascial pain involving the neck and cervicoscapular region may be associated with more than one active myofascial trigger point. Although local anesthetic trigger point injection is used in clinical practice, the optimal extent of treatment is uncertain. Previous studies have mainly compared different injectates, dry needling, physical therapy, or different injection techniques. There is limited evidence directly addressing how many active trigger points should be treated during the same treatment session.

The clinical question of this study is whether treatment should be focused on the dominant active trigger point or extended to other active trigger points identified in predefined cervicoscapular muscles. Treating more trigger points may provide greater pain relief and functional improvement. However, it also requires more needle insertions, a greater total volume of local anesthetic, a longer procedure, and potentially greater post-procedure discomfort. If focused treatment provides similar clinical benefit, additional injections may represent unnecessary treatment burden.

Participants with chronic myofascial neck or cervicoscapular pain and active trigger points in at least two different muscles will be randomized in a 1:1 ratio to a focused injection group or a multi-target injection group. The upper trapezius, levator scapulae, and infraspinatus muscles will be evaluated bilaterally before randomization. Active trigger points and the dominant active trigger point will be identified before group allocation is revealed.

In the focused injection group, the dominant active trigger point that best reproduces the participant's usual clinical pain will be treated. In the multi-target injection group, the active trigger points identified in the muscles included in the study protocol will be treated. Latent trigger points will not be injected.

All procedures will be performed under ultrasound guidance using the same injection technique. Each treated trigger point will receive 1 mL of 1% lidocaine. Only one injection session will be performed. Participants will not be informed of their treatment allocation, and follow-up assessments will be performed by an assessor who is blinded to group assignment.

The primary outcome is average neck and cervicoscapular pain intensity during the previous 7 days, measured using a 0-10 Numeric Rating Scale at 4 weeks. Secondary outcomes include pain at 1 week, Neck Disability Index score at 4 weeks, global improvement, procedure duration, pain 24 hours after the procedure, and adverse events.

The main objective is to determine whether a multi-target injection strategy provides additional clinical benefit compared with a focused injection strategy and whether any additional benefit is sufficient to justify the increased procedural burden.