Trigger point injections (TPI) are used to treat extremely painful and tender areas of muscle. Normal muscle contracts and relaxes when it is active. A trigger point is a discreet knot or tight, ropy band of muscle that forms when muscles fail to relax. The knot often can be felt under the skin and may twitch involuntarily when touched (jump sign).
A small needle is inserted into the trigger point and local anesthesia (e.g. lidocaine, procaine, bupivacaine) or anti-inflammatory/steroid is injected. Insertion of the needle inactivates the trigger point and thus alleviates pain. Additional treatment may be needed to achieve sustained relief.