The low back pain remains a major burden for patients and health care providers. In about 45% of patients with low back pain, the cause is degenerative intervertebral disc. The degenerative process may result in disc herniation or internal disc disruption. Disc herniation may be either extruded or contained.
Internal disc disruption (IDD) results in annular tears, which may be classified according to the modified Dallas criteria (Figure 34-1). Extension of the tear into the annulus results in discogenic pain.
Modified Dallas criteria. (A) equals grade 0 - normal disc and (F) equals grade 5 tear.
Disc degeneration results in 2 separate phenomena that explain the painful process.
Initially, there is extension of the sensory nerve fibers beyond the outer third of the annulus, an area that previously was mechanically insensitive. These nerves may also extend into the nucleus pulposus. This leads to pain with normal mechanical loads. Secondly, there may be fracture of the end plates. This results in inflammation and the introduction of cytokines into the nucleus pulposus. Complete tear of the annulus results in leakage of the contents of nucleus into the epidural space. Contents may irritate the neural plexus in the dura, both the anterior and posterior longitudinal ligaments and dorsal root ganglion (DRG), which may result in back pain.
Contained disc herniations most often resolve with time and conservative measures. Internal disc disruption is likely to continue to cause pain. Interventional pain management approaches may be of help in these cases.
The International Association for the Study of Pain (IASP), in its taxonomy, has adapted the following set of criteria for diagnosing IDD:
No visible disc herniations seen on magnetic resonance imaging (MRI) or computed tomography (CT).
During provocation discography injection of the suspected disc, recreation of the patient’s exact back, and/or leg pain must occur.
Injection of the disc above or below the suspect disc must be nonpainful, and this acts as a control disc or normal disc.
A grade 3 or 4 radial annular fissure must be demonstrated on post discography CT (Figure 34-2).
Postdiscogram CT scan with Dallas grade IV tear.
PERCUTANEOUS RADIOFREQUENCY DISCECTOMY—DISK-IT-11
Composed of 2 straight sharp insulated needles of 15 or 20 cm length with active tips of 20 mm.
The proximal end of active tip has a radiopaque marker.
In addition, 2 thermocouple electrodes of suitable length (15 or 20 cm) are needed for electro stimulation and making radiofrequency lesion bilaterally in the annulus.
This technique can be used to help treat pain caused by internal disc disruptions of the thoracic and lumbar discs. The diagnosis should be made ...