The role of radiofrequency in failed back surgery patients.

There are a multitude of potential causes for both residual leg pain and residual back pain following surgery. In a minority of patients there may be pathology from an adjoining segment or recurrence of the preoperatively existent anatomic abnormality. In many others surgery fails because the damage was already irreparable by the time the anatomic abnormality was corrected. In residual leg pain this is due to radiculopathy, with or without centralization into the dorsal horn. In residual back pain inflammation or scar formation in the anterior epidural space plays a major role. The role of radiofrequency (RF) has been limited for two reasons. First, because RF is destructive in nature, it is contraindicated in the treatment of neuropathic pain. Second, the anterior epidural space is innervated by the sinuvertebral nerve, which runs too close to the main segmental nerve to apply RF safely. Recently the concept of heat as being the primary active factor in RF lesions has come under discussion and has led to the development of pulsed RF (PRF), which is a nondestructive method of exposing tissue to RF electric fields. Because PRF is nondestructive, it is potentially suitable for the treatment of neuropathic pain and it can also be applied at the origin of the sinuvertebral nerve. The initial clinical results have been promising, but controlled studies are still lacking.