Trigger Point Injection Technique

Updated: Apr 03, 2017
  • Author: Stephen Kishner, MD, MHA; Chief Editor: Erik D Schraga, MD  more...
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Technique

Needling and Injection of Trigger Point

Location of trigger point

Palpation of muscles for trigger points may exhibit a palpable taut band or cord of tense muscle fibers approximately 1-4 mm in diameter. The examiner should palpate along this band to locate the point of maximum tenderness, which is the area identified as the trigger point. Pressure is held firmly to elicit the referred pain pattern.

Palpation of an active trigger point often elicits a “jump sign” or local twitch response. A jump sign is a jump or involuntary reflex–like movement of the patient that is disproportionate to the amount of pressure exerted, is reproducible, and may correspond to the degree of irritability of the trigger point. [5]

Localized twitch response refers to a localized twitch of part of the muscle when the trigger point is rolled under the fingers or a needle is inserted into the trigger area. This twitch may be intense enough to cause a notable jerk or contraction of the muscle fibers in the taut band, lasting up to 1 second. [5]

Injection

Once a trigger point has been located and the overlying skin has been cleansed with alcohol, the clinician should isolate the trigger point with a pinch between the thumb and index finger or between the index and middle finger with stabilizing pressure to prevent the trigger point from rolling away from the advancing needle.

The needle is inserted 1-2 cm away from the trigger point and then advanced into the trigger point at an acute angle of 30º to the skin. (See the image below.) Before advancing the needle into the trigger point, the physician should warn the patient of the possibility of sharp pain or muscle twitching as the needle contacts the trigger point. Aspirate before injection to avoid intravascular injection.

Trigger point injection. Trigger point injection.

Once the needle is inside the trigger point, a small amount (0.2 mL) of anesthetic is injected. The needle is withdrawn to the level of the subcutaneous tissue, then redirected superiorly, inferiorly, laterally, and medially. The needling and injection process is repeated in each direction without withdrawal of the needle until the local twitch response is extinguished or until the muscle relaxes. [5]  Pressure should be applied over injection sites.

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Postprocedural Care

Stretching

Stretching after trigger point injection is an integral part of treatment. The physician should stretch involved muscles to try to obtain full length.

Before stretching, it may be helpful to apply a few sweeps of vapocoolant spray in a parallel direction over the muscle and its referred pain pattern to relax remaining tense fibers. [2]  This should be followed by the application of a hot pack over all injected trigger points.

After heat has been applied topically for several minutes, the patient should perform full active range of motion of the muscle several times to relieve residual stiffness, evaluate the effectiveness of the procedure, and reestablish awareness of normal muscle function.

Strenuous activities should be avoided for at least the period of postinjection muscle soreness. However, the patient is encouraged to use the muscle with full range of motion rather than hold it in a fixed, shortened position. [2]

Exercise

Active exercise is a critical part of the treatment program and will determine whether trigger point injection treatment is effective. Exercises can be designed to target stretching, strengthening, or conditioning of muscles.

Exercise designed for stretching the involved muscles is the key to the relief of myofascial pain. Improved conditioning and increased strength reduces the likelihood of developing trigger points. As the trigger points are inactivated and any rest pain resolves, a carefully graded exercise program begins to increase endurance.

Once tolerance of stretch is achieved, the patient may progress to strengthening exercises. These may be either isotonic or isometric, though isotonic exercises are usually better tolerated. Strengthening exercises should be prescribed with a certain number of repetitions. They should be executed smoothly and slowly, with pauses between each repetition.

When tolerated, conditioning exercises should be added and done at least twice weekly. These exercises include swimming, bicycling, tennis, jogging, and jumping rope. [5]

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Complications

Complications may include the following [2] :

  • Vasovagal syncope
  • Skin infection
  • Pneumothorax
  • Needle breakage
  • Hematoma formation

Infection can usually be avoided by employing sterile technique. Avoid pneumothorax complications by never aiming a needle at an intercostal space. Needle breakage is avoided by never inserting the needle all the way to its hub. Hematoma formation can be avoided by applying direct pressure for at least 2 minutes after injection.

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