Discogenic low back pain (DLBP) is responsible for at least 40% of chronic LBP. Radial or circumferential tears (IDD) in the outer third of the posterior annulus lead to nociceptor stimulation through inflammatory or mechanical means resulting in acute DLBP. Over time, subsequent nerve in-growth into the annular tears is correlated with the expression of substance P leading to chronic DLBP.
DLBP results from IDD that leads to nerve irritation within the disc. In contrast, a herniated disc leads to mechanical or chemical irritation of nerve roots within the spinal canal resulting in LBP and sciatica.
The symptoms of DLBP are LBP worse with axial loading (sitting, standing or lifting) and better with recumbency. The pain can be referred into the legs but not in a sciatic distribution. Exam findings include muscle spasms, painful range of motion, and painful palpation. The neurological exam and imaging studies are often unremarkable. Discography is the only reliable means of diagnosing DLBP.
The IDET procedure consists of placing a semi-rigid catheter within the posterior annular tear of the painful disc. The area is then heated from 65 to 90°C over 16.5 minutes. The IDET mechanism of action in reducing DLBP is unknown at this time.
Indications for the IDET procedure mandate a positive lumbar discogram. Contraindications include disc degeneration with >50% disc height loss and a previously operated disc. Potential complications include bleeding, infection, and nerve root injury.