If your lower back pain is muscle-related, your doctor may suggest a trigger point injection.
Myofascial trigger points are felt to be hyperirritable foci in muscles and fascia associated with taut muscle bands. Trigger points are diagnosed by palpation and produce a local twitch response and a referred pain pattern distal to the site of muscle irritability.
Trigger points cannot be properly diagnosed in the acute stages of low back pain when muscle spasm and inflammation are present. Initially, trigger points generally respond to a program of stretching and correction of poor postural mechanics with or without other modalities, such as superficial heat or cold.
Trigger point injections should be reserved for patients who have not responded in the first 4 to 6 weeks to a properly directed program and appropriate pharmacologic intervention.
How Trigger Point Injections Are Done
The trigger point injection should be carried out under antiseptic technique. There is little evidence to support any beneficial effect of adding corticosteroid to the injection. In fact, a saline injection can as effective as a local anesthetic. However, for patient comfort and to assist in deciding upon therapeutic efficacy, injecting a local anesthetic such as lidocaine and/or mepivacaine is acceptable.
Some trigger points may require more than one injection, but generally more than 3 injection of the same trigger point is not indicated. Repeated trigger point injections may cause local muscle damage and scarring, which may potentially lead to a poor functional outcome.