Trigger Point Injection
(Injection, Trigger Point)
A trigger point is a painful area in a muscle. It may feel like there is “knot” in the muscle or an area of tightness. When pressure is applied to the trigger point, the pain spreads out to other areas of the body.
A trigger point injection is a shot that is given in this painful spot.
If you have a trigger point in the thigh muscle, the doctor can give an injection to relieve pain.
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Reasons for the Procedure
Trigger point injections are given to reduce pain and increase physical functioning so you can participate in a physical therapy program.
Problems from the procedure are rare, but all procedures have some risk. Your doctor will review potential problems, like:
- Tenderness, bruising, or bleeding at the injection site
- Allergic reaction to the local anesthetic or medication
- Organ damage (rare)
If you smoke, talk to your doctor about ways to quit. Smoking can weaken your immune system and slow healing.
You should not have this injection if you:
- Have allergies to the local anesthetic or medications being used
- Have a current infection
- Have a bleeding disorder
- Are pregnant
What to Expect
Prior to the Procedure
Before the procedure you may need:
- A physical exam
- Imaging tests to evaluate the spinal structures with x-rays or an MRI scan
- To discuss allergies that you may have to the anesthetic, pain medication, or latex
In addition, talk to your doctor about your medications. You may have to stop taking some medications up to one week or more before the procedure.
Depending on where your trigger point is, you may need someone to drive you home after the procedure.
You will typically remain awake during the procedure. A local anesthetic may be used to numb the area where the injection will be given.
Description of the Procedure
First, the skin around the painful area will be cleansed with an antiseptic. Next, the doctor will locate the trigger point. This may be done by feeling for the painful area with their fingers. Once the trigger point in found, a thin needle containing medication will be injected. The injection may contain a long-acting pain reliever, a water solution, or a corticosteroid to reduce inflammation. Botulinum toxin is also sometimes used for trigger point injections associated with muscle contraction. Sometimes the doctor will simply put the needle into the trigger point and not inject any medication. This is all done to break the pain cycle at the trigger point. If you have more than one trigger point, you may need several injections.
Some doctors may use needle-guided electromyography (EMG) to locate the trigger point. With this approach, a needle will send information to a monitor, which will allow the doctor to make sure he has located the right spot.
How Long Will It Take?
The injection takes a few minutes.
Will It Hurt?
When the doctor feels for the trigger point, you will have discomfort. You will also feel a pinching sensation when the needle goes through your skin. You may have pain, but it should not last long.
Post Procedure Care
At the Care Center
The staff will apply pressure to the injection site and place a bandage. You will be observed for a short time to make sure you do not have any poor reactions to the injection. Then, you will be able to go home or return to work.
To reduce soreness, apply ice or a cold pack to the affected area to ease discomfort. Do not use heating pads or warm packs for 1-2 days.
Your doctor may advise pain medications. You may need to meet with your physical therapist soon after the injection to take advantage of the pain relief in your muscles.
You may have pain relief for weeks or even months. In some cases, you may need to have more than one trigger point injection. Talk to your doctor about how often you will need this treatment.
Call Your Doctor
Call your doctor if any of these occur:
- Signs of infection, including fever and chills
- Redness, swelling, increasing pain, bleeding, or discharge from the injection site
- Numbness, tingling, pain, or weakness
- New or unexpected symptoms
If you think you have an emergency, call for emergency medical services right away.
American Chronic Pain Association
Ortho Info—American Academy of Orthopaedic Surgeons
Trigger point injections. Memorial Sloan-Kettering Cancer Center website. Available at: https://www.mskcc.org/cancer-care/patient-education/trigger-point-injections. Updated August 28, 2017. Accessed December 20, 2017.
Trigger point injections. University of Wisconsin Hospital website. Available at: https://www.uwhealth.org/healthfacts/pain/6370.html. Updated January 15, 2015. Accessed December 20, 2017.
Trigger point injection therapy. Fibromyalgia Symptoms website. Available at: http://www.fibromyalgia-symptoms.org/fibromyalgia_injections.html. Accessed December 20, 2017.
Last reviewed November 2018 by EBSCO Medical Review Board Michael Woods, MD, FAAP Last Updated: 12/20/2014