Design and optimization of radio-frequency (RF) ablation probes for pain therapy

Chronic back pain results most frequently from degenerative osteoarthritis of the joints of the vertebra, called the facet joints, where much of the movement of the spine occurs. When conservative therapy fails, a commonly performed procedure is radio-frequency (RF) ablation of the nerve supply to the affected facet joints. This procedure involves the use of RF ablation probes that can be inserted into the tissue surrounding the targeted area. Commercially available probe designs are akin to sharp needles, expected to create large field intensities at their tip (E. R. Cosman, Jr. and E. R. Cosman, Sr., Pain Medicine, vol. 6, no. 6, 2005 ). However, these knife-edge probes do not offer much control over the induced temperature profile (“RF lesion”). Hence, this procedure is accompanied by a high risk of damaging the surrounding tissue, including motor nerves.