The paraspinal muscle injection is a useful diagnostic and therapeutic procedure for myofascial pain.
After informed consent is obtained, the patient is placed in the prone position. The appropriate thoracic and lumbar regions are palpated. The injection sites are identified as points of maximal tenderness to deep palpation, reproducing the patient’s pain complaint. This may or may not result in referred pain. The patient is prepared in a standard aseptic fashion over an area large enough to allow palpation of landmarks, and sterile technique is used throughout the procedure. A 1½-in. (4-cm), 21- to 25-gauge needle is inserted at the point of maximal tenderness and advanced to the area of the trigger point. After negative aspiration, the trigger point area is injected with 4 mL of local anesthetic (Fig. 67-29).
FIGURE 67-29. Paraspinal musculature. Trigger points and referred pain patterns.
The referred pain pattern for the thoracic paraspinal muscles often involves the scapular and chest wall region, as well as the lower thoracic paraspinal muscles and abdomen region. The referred pain pattern for the lumbar paraspinal muscles often involves the buttock, iliac crest, and sacroiliac joint region. These muscles involve the erector spinae, semispinalis cervicis, longissimus capitis, longissimus cervicis, longissimus iliocostalis thoracis, iliocostalis lumborum, and semispinalis multifidus. The patient should be fully familiar with the stretching program for the affected paraspinal muscle and be instructed in a home program. Failure to include a home stretching program usually results in short-term relief.
Significant complications are uncommon with paraspinal trigger point injections.