Relieving Pain Without Fusion
by Joseph P. Zuhosky, MD
 Chronic “discogenic” pain represents one of the most difficult conditions seen by a spine specialist. These patients have limiting symptoms of pain—generally in the low back—presumed to result from an internal derangement within the nucleus pulposus of the disc or its outer fibers, the annulus fibrosus. The cardinal feature is disruption of the annulus fibrosus, seen as a high intensity zone on magnetic resonance images (MRIs). These patients generally experience greater pain when sitting as opposed to standing or walking, and the pain is usually intense for the first 30 minutes of each day. Pain also increases when:
• rising from a seated position
• coughing or sneezing
• lifting a weight away from the body
• bending or twisting at the waist
Until recently, a fusion represented the only viable treatment option. Because this procedure has a variable success rate and results in loss of mobility and rapid progression of degenerative changes at adjacent levels, alternative treatments have been sought for many years. IDET represents a cutting-edge alternative. IDET is an outpatient procedure performed with conscious sedation. A navigable catheter is placed through an introducer needle into the disc and coiled within the annulus fibrosus. The catheter is heated to 90°C over approximately 17 minutes. IDET theoretically works to: (a) thermally ablate, or destroy, the nociceptive (pain) nerve fibers in the outer third of the disc; (b) thermally coagulate collagen within the annulus fibrosus with remodeling and “stiffening” over time; and (c) decompress disc material.
In our experience, ideal candidates for IDET have had lumbar pain for more than six months, failed to respond to aggressive, non-operative care including physical therapy, and demonstrated a positive, but non-sustained response to an epidural steroid injection. They also must demonstrate pain reproduction upon provocative discography with a CT discogram, which demonstrates internal disc and annular disruption.
Additionally, the MRI must demonstrate preserved disc height (at least 50 percent of normal height) preferably with high intensity zone or degenerative “black disc,” but no significant disc protrusion or stenosis. The predominant symptoms are sitting intolerance and good standing tolerance. Motivated patients with realistic expectations of improved sitting tolerance, reduced pain and use of pain medications represent the optimal candidates for this procedure.
Following the procedure, most patients will return to employment within the first week. A lace-up lumbar corset is worn for the first 6–8 weeks and walking is common after three days (20 minutes a day the first two weeks and increasing as tolerated). Patients may resume driving the day after the procedure, but sitting is restricted to 30–45 minutes for the first two weeks. Typically 8–12 weeks of intensive physical therapy begins six weeks after the procedure.
The research and literature on IDET has consistently shown a statistically significant improvement with its use, but to varying degrees. The most rigorous study by Dr. Kevin Pauza suggests that approximately 60 percent of carefully selected candidates who meet all of these criteria will realize significant improvements in their sitting tolerance and 50 percent or greater relief of their symptoms. Total Spine Specialists’ experience with this procedure approximates these results.
IDET is a viable alternative to a fusion for patients with longstanding, limiting discogenic pain. It is important to keep in mind, however, that a very small percentage of patients will turn out to be ideal candidates for this procedure. Patient selection remains a crucial component for successful results.
Source: Intradiscal Electrothermal Treatment for Chronic Discogenic Low Back Pain. Prospective Outcome Study with a Minimum 2-Year Followup. Spine 2002; 27:966–974.
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