Discogenic back pain
Discogenic back pain is mostly mediated through the vertebral end plates above and below the intervertebral disc. The main nerve supply to the vertebral end plate is the basivertebral nerve. The basivertebral nerve is a small nerve that enters the vertebral body though the central ventral aspect, and from there it sends sensory branches to the end plates on both sides of the vertebral body.
The diagnosis of discogenic back pain is not always easy, and most of the time the diagnosis can only be confirmed with a diagnostic provocative discogram. Disc changes on MRI scans are on most occasions not helpful to make a diagnosis of discogenic back pain, however when there are Modic type I and to a lesser extent Modic type II end plate changes visible on MRI, research has shown a high correlation with discogenic lower back pain from that disc level.
The Procedure
The main aim of the procedure is to deliver a radiofrequency heat lesion at the basivertebral nerve to denervate the vertebral end plate.
Radiofrequency denervation has been used for many decades to provide pain relief for facet joint mediated spinal pain. Radiofrequency denervation is administered through a cannula with an exposed tip to provide a localised heat lesion at the tip of the cannula. A heat lesion of 80 to 90 degrees Celsius is usually enough to lesion the nerve. After denervation the targeted nerve usually regenerates over a period of 18 months to 2 years, and then pain may return. Radiofrequency denervation can be repeated to provide ongoing relief for spinal pain.
To denervate the basivertebral nerve, a small trocar is used to create a tunnel through the vertebral pedicle to the middle of the vertebral body. The radio frequency cannula is advanced under fluoroscopic (xray) guidance through this tunnel to the middle of the vertebral body to provide the localised heat lesion and denervate the basivertebral nerve.
Risks
There is a very low rate of complications with basivertebral nerve ablation. It is not unusual to feel discomfort at the site of the procedure or in the legs for a few days or weeks after the procedure. You may need additional analgesic medication during this recovery period, and it is important to keep moving around as able. Heat or cold packs may also provide some relief.
Outcomes
Research and our own experience have shown promising results of basivertebral nerve ablation in the treatment of discogenic back pain in patients with end plate changes seen on MRI. Improvement in back pain is usually noticeable within 4 – 6 weeks of treatment.