Today, I wanted to write about the first bedside procedure I learned how to perform as an intern: the trigger point injection. I’ve heard that many residents have never done one of these, so I wanted to share that they have worked very well for me.
Musculoskeletal pain is a very common complaint in the ED and many of us have a special cocktail we refer to when treating it, usually involving a combination of topical analgesics, NSAIDs, and muscle relaxants. However, there is a time when these oral medications aren’t enough in the ED, or the patient has already failed outpatient management, and that is when the pain involves a trigger point.
A trigger point is a palpable area of muscle spasm that feels extra taut, which many of us commonly call a “knot.” While a patient will commonly complain of a broad region of pain, the pain is typically originating from the trigger point and the remainder is referred pain. Trigger points are significantly more tender than the surrounding region and pain is easily reproducible on palpation. There is no imaging to identify a trigger point (not even ultrasound); you have to feel it.
You can find everything you need easily: an alcohol swab, 1-2 mL local anesthetic (1-2% lidocaine without epinephrine, 0.25-0.5% bupivacaine, OR a 50-50 combination of the two), a 22 to 25 gauge needle, and a band-aid.
The procedure is fast and easy, and relief is nearly instantaneous when done correctly.
Steps:
1. Identify the trigger point and clean the area around it with the alcohol swab.
2. Insert the needle at a 30-degree angle, deep enough to penetrate the point (make sure your needle is long enough for deeper muscles!) When you hit the knot, you may elicit a “twitch” response, which is pathognomonic for a trigger point. Inject some anesthetic.
3. Pull out almost to the surface of the skin and redirect to deliver a small amount of anesthetic to each of the 4 quadrants of the trigger point. It is important to pull out almost all the way to avoid hematoma.
4. Apply a band-aid when complete.
Contraindications:
1. Overlying cellulitis
2. Nearby critical anatomical structure
3. Allergy to local anesthetic
4. Coagulopathy or bleeding disorder
5. Can’t feel a trigger point, or can't find a maximal point of tenderness – not a contraindication… but wouldn’t recommend, mainly because you and the patient are unlikely to be satisfied. And you’re more likely to become one of those people who say that trigger point injections don’t work!
Be well,
Maisa Siddique, PGY3
Sources
https://www.aliem.com/trigger-point-injection-musculoskeletal-pain/
https://www.acep.org/patient-care/map/map-trigger-point-injection-tool/