Indications

Intra Discal Electro Thermal Annuloplasty (IDET) is a recently developed technique for relief of discogenic pain. It may be an alternative to spinal fusion in some people. Patients are usually referred from the pain clinic to an appropriate spinal surgeon for this procedure.

Indications

• Those with discogenic low back pain and mild sciatica that does not improve with six months of conservative therapy. Usually mild disc degeneration confined to one or two levels.
• Chronic annular tears and small disc herniations causing persistent sciatica.

Contra-indications

• Severe and widespread disc degeneration
• Spinal Stenosis
• Large disc prolapses
• Those with neurological leg weakness

Technique

Disc Selection

• The appropriate disc is selected using MRI scans and the results from Provocation Discography.

Technique

• A hollow needle is entered into the appropriate disc from the side using X-ray Guidance , under local anaesthetic, and light intravenous sedation .
• Through this hollow needle is inserted an electrode wire (heating wire) which has several centimetres of its tip bared, and the rest insulated.
• The electrode wire is then curved around the inside of the disc within the nucleus pulposus, until it lies opposite the Posterior Annulus of the disc, usually where the annular tear is situated. Once the position is correct, the electrode wire is heated electrically to 90 deg C for 15 minutes.

Mechanism

• Using electro-cautery deadens the nerve endings that supply the posterior annulus i.e. those that are transmitting the discogenic pain (see also Radiofrequency Facet Denervation). "Cooking" the annulus also causes protein changes adjacent to a chronic Annular Tear, sealing up the hole, preventing leakage of inflammatory mediators into the epidural space, and reducing the sciatic pain in the leg(s).

Aftercare

• A lumbar support is worn for 6 - 8 weeks, followed by physiotherapy. Lifting and bending are initially avoided to allow the disc to heal.

Complications

• Failure to treat the back pain / sciatica - this may occur due to selecting the wrong disc, or if the pain was not truly discogenic in the first place. 
• Infection - Discitis (disc infection) can be life threatening requiring appropriate antibiotics. The technique therefore has to be performed under strict aseptic conditions.
• Bleeding - in those with coagulation problems.
• Nerve injury - by the initial hollow needle whilst it is being inserted into the disc. Depending on the magnitude of the injury, this usually settles spontaneously in several weeks.