Summary

• Intradiscal electrothermal therapy (IDET) is a minimally invasive surgical procedure for the treatment of chronic low back pain in patients with intact or slightly degenerated discs that are presumed to be responsible for the pain.
   
• Among the adult population, approx. 35% have had transient or chronic low back pain within the past year. Approx. 3.5% of all adults are seriously affected by low back pain.
   
• The indications for treatment with IDET are far from having been clarified as yet.
   
• So far there has only been a single randomised controlled clinical trial of IDET, although there are numerous clinical outcome studies and reviews of data on patients who have undergone this treatment. The literature does not yet provide a clear picture of IDET’s clinical effect, though.
   
• As there is no convincing documentation for the indications and treatment results, in the event that IDET is introduced in Denmark this should take place via a randomised controlled clinical trial.

The disease
Low back pain is an extremely common condition in Denmark. Among the adult population, approx. 35% have had transient or chronic low back pain in the past year [1]. Chronic pain is understood to mean persistent pain that has lasted for more than 7 weeks [2]. Approx. 3.5% of all adults are severely affected by low back pain at any one time [3].

The pain can be attributable to various conditions in and around the spinal column, including various types of damage to the intervertebral discs, e.g. herniation, disruption (fissures), prolapse and degeneration.

The differentiation of discogenic pain, which is seen with disc disruption without actual root compression, is difficult. Moreover, the condition is poorly defined as the pain can stem from other adjacent structures, for example the facet joints, muscle tissue or degenerated discs with associated bone inflammation.

The causes of the discogenic pain seen with disc disruption are complex and far from fully understood [4]. Some patients with chronic low back pain have neither disc protrusion, prolapse nor degeneration. One of the hypotheses is that chronic low back pain is primarily discogenic and derives from cracks that extend from within the disc nucleus (nucleus pulposus) to the outer part of the disc (annulus fibrosus), though without penetrating it [5;6]. In the outer 1/3 of the annulus fibrosus there are nerve fibres that can possibly be stimulated, thereby generating the pain. Moreover, fine nerve endings can grow deeper into the disc via the cracks and cause pain upon movement or strain upon the spinal column [2;6].

The great problem is to localise the structure in the back causing the pain. Degenerated discs only infrequently cause pain and, as mentioned above, the pain could be generated from many possible locations, both inside and outside the vertebral column.