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.

• Lidocaine 1% Trigger Point Injection (Drug): Ultrasound-guided trigger point injection with 1 mL of 1% lidocaine per treated active myofascial trigger point. Each trigger point will receive a single needle insertion and a single injection. No additional needle movement or redirection will be performed to elicit a local twitch response.

Primary outcomes

• Average Neck and Cervicoscapular Pain Intensity [4 weeks after the injection]: Average pain intensity over the previous 7 days will be assessed using an 11-point Numeric Rating Scale (NRS), where 0 indicates no pain and 10 indicates the worst possible pain.

Secondary outcomes

• Average Neck and Cervicoscapular Pain Intensity at 1 Week [1 week after the injection]: Average pain intensity over the previous 7 days will be assessed using an 11-point Numeric Rating Scale (NRS), where 0 indicates no pain and 10 indicates the worst possible pain.
• Neck Disability Index Score [4 weeks after the injection]: Neck-related disability will be assessed using the Neck Disability Index (NDI), a 10-item questionnaire evaluating pain and limitations in daily activities. Each item is scored from 0 to 5, yielding a total score ranging from 0 to 50. Higher scores indicate greater neck-related disability.
• Global Improvement [4 weeks after the injection]: Participants will rate their overall perceived change in symptoms compared with their condition before treatment using a 7-point Patient Global Impression of Change (PGIC) scale. The scale ranges from 1 (very much improved) to 7 (very much worse), with 4 indicating no change. Lower scores indicate greater perceived improvement.
• Procedure Duration [Baseline]: Procedure duration will be recorded as the time from the first needle insertion to removal of the final needle.
• Post-Procedural Pain [24 hours after the injection]: Pain related to the injection procedure will be assessed using an 11-point Numeric Rating Scale (NRS), where 0 indicates no pain and 10 indicates the worst possible pain.
• Adverse Events [From the injection procedure through 4 weeks after the injection]: Adverse events related to the injection procedure will be recorded throughout the follow-up period.

Sex: All, ages: 18 Years to 65 Years

Inclusion Criteria:

* Age 18 to 65 years
* Chronic myofascial neck or cervicoscapular pain for at least 3 months
* Average pain intensity during the previous 7 days of at least 4/10 on the Numeric Rating Scale
* Presence of active myofascial trigger points in at least two different muscles among the upper trapezius, levator scapulae, and infraspinatus muscles
* Willingness to participate in the study and provide written informed consent

Exclusion Criteria:

* Cervical radiculopathy or myelopathy
* Fibromyalgia
* Neurological, rheumatological, or structural disease that may explain the neck or cervicoscapular pain
* History of major surgery involving the neck or shoulder girdle, or trauma that may significantly affect clinical assessment
* Trigger point injection or dry needling in the cervicoscapular region within the previous 3 months
* Active infection, open wound, or significant skin lesion at the injection site
* Active systemic infection
* Known allergy to lidocaine or other amide-type local anesthetics
* Known bleeding disorder, clinically significant thrombocytopenia, or anticoagulant treatment associated with an unacceptable bleeding risk for injection
* Pregnancy
* Severe cognitive or communication impairment that would prevent reliable completion of study assessments
* Inability or unwillingness to provide written informed consent

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• Suputtitada A, Chen CPC, Ngamrungsiri N, Schmitz C. Effects of Repeated Injection of 1% Lidocaine vs. Radial Extracorporeal Shock Wave Therapy for Treating Myofascial Trigger Points: A Randomized Controlled Trial. Medicina (Kaunas). 2022 Mar 26;58(4):479. doi: 10.3390/medicina58040479. PMID 35454318
• Lugo LH, Garcia HI, Rogers HL, Plata JA. Treatment of myofascial pain syndrome with lidocaine injection and physical therapy, alone or in combination: a single blind, randomized, controlled clinical trial. BMC Musculoskelet Disord. 2016 Feb 24;17:101. doi: 10.1186/s12891-016-0949-3. PMID 26911981