Intradiscal Electrothermal Therapy (IDET)
This procedure holds promise for those who suffer discogenic lower back pain. It is a type of thermal modification known as intradiscal electrothermal therapy (IDET). The new therapy uses heat delivered directly within the symptomatic discs to shrink collagen fibers and thermocoagulate nerves to overcome lower back pain. The studies on IDET have proven it to be effective for well-selected patients, with about 75% of those undergoing treatment recording satisfactory outcomes of reduced pain and increased mobility. IDET not only holds promise in terms of helping low back patients significantly reduce pain and improve function, but also opens an avenue for reduction of medical costs when compared with the option of spinal fusion.
How IDET works
Age or injury may produce tears or cracks in the wall of intervertebral discs. Fissures form in the disc annulus (outer ring) and become filled with small nerve endings and blood vessels. For many patients these fissures are the source of chronic pain. In theory, the IDET procedure thickens and strengthens the disc wall by applying controlled heat to the annulus, thereby contracting collagen. This heat lesion also thermocoagulates pain nerve fibers within the disc annulus, thus eliminating pain sensation in the disc.
A navigable catheter that has a 5-cm coil with a heating element and a 17-gauge introducer needle is inserted into the disc by means of fluoroscopic guidance and then maneuvered to achieve a 360-degree penetration. Heat is introduced into the disc through the electrothermal portion of the catheter. The heating temperature progresses during 14 to 17 minutes from 65 degrees C to 90 degrees C. The entire IDET procedure is performed on an outpatient basis and takes approximately one hour with an additional hour of recovery time.
Some patients report immediate relief, but it is more likely that significant pain relief and improvement in function occurs as the disc heals—which generally takes four to twelve weeks. Patients typically return to sedentary work within one week of the procedure. After six weeks, more strenuous physical activity with a formal spinal-strengthening program may begin. Optimal outcome should be expected at six months.
Who can benefit from IDET
Candidates for IDET are those who have chronic discogenic back pain that has not responded to aggressive, non-operative therapy. Usually, patients have had lumbar pain for at least six months duration, have had a normal neurologic exam, and have undergone an MRI showing that there is no neural compressive lesion. Discography is essential to confirm that the disc itself is the source of the pain, to identify the number of symptomatic discs, and to locate the annular tears within the disc(s). IDET is not indicated for severe disc degeneration, nerve compression, spinal instability, and/or spinal stenosis.
IDET is a minimally invasive procedure that may benefit patients who are candidates for interbody fusion and also fall within the IDET inclusion profile.