Mechanisms Of Action

Evans's speculation in 1930 that epidural injections achieve their effect by lysis of adhesions and displacement of nerve roots (15) has given way to other theories. In 1983, White, an orthopedic surgeon, made the logical point that adhesions are difficult to dissect with a scalpel, thus throwing considerable doubt on the bulk effect of large volume injections (24). The concept of an injection displacing and stretching nerve roots (25) has never been validated.

It is now generally accepted that epidural steroids give relief by their anti-inflammatory effects. Green et al. noted that inflammation of the involved spinal nerves has often been documented at surgery (26), and there is strong evidence of inflammation in lumbar radiculopathy and disc degeneration. In fact, McCarron et al. observed an intense inflammatory reaction after injection of autologous disc material into the epidural spaces of dogs and a rapid onset of fibrosis (27). Franson et al. demonstrated high levels of phospholipase A2 (PLA2) around symptomatic disc herniations and painful discs. Subsequently, they engendered an inflammatory response by injecting PLA2 into mouse paws (28). PLA2 exerts its effect by liberating arachidonic acid from cell membranes, causing an intense inflammatory reaction in adjacent tissues (4). The inhibition of PLA2 activity is one of the anti-inflammatory actions of corticosteroids (29,30).

Johansson et al. postulated additional effects of corticosteroids in a study of rats by demonstrating that the corticosteroids reduce signal transmission in the unmyelinated C-fibers, which carry nocioceptive information, but not in myelinated fibers (31).

If local anesthetics are combined with the steroids, they give immediate pain relief. This is theorized to have a beneficial psychological effect in that it allows a patient to consider the pain as treatable, and that it breaks the postulated pain-muscle spasm-ischemia-pain cycle (25).

Cure Tennis Elbow Without Surgery

Cure Tennis Elbow Without Surgery

Everything you wanted to know about. How To Cure Tennis Elbow. Are you an athlete who suffers from tennis elbow? Contrary to popular opinion, most people who suffer from tennis elbow do not even play tennis. They get this condition, which is a torn tendon in the elbow, from the strain of using the same motions with the arm, repeatedly. If you have tennis elbow, you understand how the pain can disrupt your day.

Get My Free Ebook


Post a comment