By Jonathan Chu, MD
Interventional Pain Medicine
PM&R

Trigger point injections (TPI) are one of the easiest, safest, and most common procedures that pain doctors perform.

In this video, you’ll learn everything you need to know about this procedure before you have it done.

Conditions that Trigger Point Injections Treat

First, you should know that trigger point injections are used primarily to treat a condition known as myofascial pain syndrome.

This is an extremely common condition and one of the most common sources of chronic pain.

It’s characterized by tight, over-tensioned, and taut bands of muscle. This painful muscle dysfunction usually occurs in the neck or low back, but can also occur in almost any other muscle group of the body.

Sometimes these taut and painful muscles are purely the consequence of stress, anxiety, or physical deconditioning.

They can also be the result of poor body mechanics over time, such as bad posture when sitting, or incorrect lifting techniques.

Also, more often than not, this painful muscle syndrome occurs in response to underlying problems in the nerves and joints deeper to the muscle.

Examples of this would be pinched nerves in the spine (radiculopathy), facet joint arthritis, or ligamentous injury.

If myofascial pain syndrome occurs in the neck and upper back, it can also trigger other painful conditions, such as tension headaches and occipital neuralgia. Thus, treating the muscle tension in the neck can often lead to relief from headaches as well.

How Trigger Point Injections Are Performed

Trigger point injections are actually one the simplest procedures that pain physicians perform.

To start, your physician will usually examine the painful area and mark the tender muscle groups to target.

Next, the area will be cleaned with a solution such as chlorhexidine, iodine, or alcohol.

Your physician will draw up the medication. This usually consists of a numbing medication that may be combined with a small dose of steroid. The steroid is often added to act as a potent anti-inflammatory.

Next, your physician will inject the areas of muscle that are most tender with small increments of the medicine.

You may feel a twitch of the irritated muscle when the needle enters, which is perfectly normal. In fact, many pain doctors believe that this is a great sign—visual evidence that the muscle is releasing.

Trigger points injections are usually performed using body landmarks to guide the needle placement. This is how trigger point injections are done in most clinics across the country, and is considered very safe and effective overall.

Personally, when I am working in higher-risk areas, such as near the thoracic cavity, or have a specific muscle that I want to target, I like using ultrasound to help me guide the needle. This way, I can visualize the needle and my targets directly while doing the procedure, increasing both accuracy and safety.

How Do Trigger Point Injections Work?

The mechanism behind trigger point injections has not been definitively proven; however there are a few prevailing theories regarding how they work.

First, it is believed that the mechanical action of the needle and the chemical action of the numbing medication help to disrupt the irritable muscle—inducing relaxation and elongation of the muscle fibers.

It is also believed that the action of the needle stimulates blood flow to the dysfunctional muscle. This helps to dilute and wash away many of the noxious inflammatory chemicals that build up in the muscle.

Interestingly, the majority of research suggests that the needle action itself is the most critical factor, and that the local anesthetic may make little difference.  

How Well Do Trigger Point Injections Actually Work?

In my experience, trigger point injections tend to work very nicely for a subset of patients.

The response to these injections can be best described as a bell curve.

On one hand, some people will try trigger point injections and only get modest relief for a week or less.

On the other end of the spectrum—there are some patients who feel almost complete relief for many months at a time.

I would say that on average, most people experience good relief for several weeks following the procedure.

While trigger points usually do not last as long as more invasive procedures, many patients consider trigger point injections to be a great option due to their safety and ease.

The scientific literature on trigger point injections is rather limited. There are a relatively small number of controlled trials looking at this procedure.

In general, the research does show that trigger point injections are an effective therapy for muscle pain. It also shows that isn’t much difference between the various needling techniques and medications used.

At this point, there is not enough research available to create definitive guidelines regarding how often they should be performed, or how many muscles should be injected each time. In this way, trigger point injections are as much of an art as a science.

Potential Complications

In general, trigger point injections are one of the safest procedures that pain physicians can perform.

By far, the most common adverse reaction is soreness in the muscles afterwards. This usually goes away completely after 3-4 days.

Some bruising is also possible, especially if you are on blood thinning medications.

Lastly, damage of surrounding structures can also be possible. For example, when working in the chest area or upper back, puncture of the lung (pneumothorax) is a possibility. However, these types of complications are exceedingly rare.

Conclusion

Overall, it can be said that trigger point injections are an excellent and low-risk treatment for a subset of patients with stubborn muscle pain and spasms. Of course, for some patients, it may only provide very short-term pain relief, and is not worth repeating; however, for others, this really simple procedure can provide many weeks of relief at a time, which makes it potentially a very valuable component of a comprehensive pain treatment plan, which should also include stretching, strengthening, ergonomics, weight loss, an anti-inflammatory diet, and also building general fitness. Thank you so much for watching everyone.

References

Alvarez DJ and Rockwell PG. Trigger Points: Diagnosis and Management. American Family Physician. 2002 Feb 15;65(4):653-661.

Benzon HT, Raja SN, Liu SS, Fishman SM, and Cohen SP. Essentials of Pain Medicine. 3rd Ed. Philadelphia, PA: Saunders; 2011.

Braddom RL, Chan L, Harrast MA, Kowalske KJ, Matthews DJ, Ragnarsson KT, and Stolp KA. Physical Medicine and Rehabilitation. 4th Edition. Philadelphia, PA: Saunders; 2011.

Desai MJ, Saini V, and Saini S. Myofascial Pain Syndrome: A Treatment Review. Pain Therapy. 2013 Jun; 2(1): 21–36.

Rathmell JP. Atlas of Image-Guided Intervention. 2nd Ed. Philadelphia, PA: Lippincott Williams and Wilkins; 2012.

Wong C and Wong S. A New Look at Trigger Point Injections. Anesthesiology Research and Practice. 2012; 2012: 492452.