Varun Rimmalapudi and Jeff Buchalter (both Gulf Coast Pain Institute, Pensacola, USA) respond to an article printed in the October issue of Spinal News International: “Radiofrequency denervation fails to provide clinically important chronic low back pain improvement“. The results were initially printed in The Journal of the American Medical Association (JAMA).
A study recently published in The Journal of the American Medical Association concluded that radiofrequency denervation, a widely utilised procedure in the treatment of back pain, provided no clinically important improvement when compared to a standardised exercise regimen. However, serious flaws as noted below have been noted in various aspects of the study design, making the conclusions of the study unreliable.
A diagnosis of facetogenic low back pain has to be established prior to the performance of radiofrequency ablation of the lumbar zygapophyseal joints. The established criteria for this is the performance of two diagnostic medial branch blocks. However, Juch et al used a single block before proceeding to radiofrequency ablation. As a result, it is very likely that the patients in the study who received the procedure did not have the clinical condition that the procedure was intended to treat.
Radiofrequency ablation treats pain by inactivating the nerve that supplies the affected joints. Hence increasing the volume of tissue that is lesioned increases the success rate of the procedure. The volume of the lesoin is in direct proportion to the size of the radiofrequency cannula, which is why larger cannulae such as 16G are used in clinical practice. However, Juch et al used a 22G cannulae, substantially reducing lesion size. They also did not utilise the standard parallel placement technique. These factors have undoubtedly increased the chance of therapeutic failure.
The study compared radiofrequency ablation to a programme focusing on movement and behaviour that lasted over eight to 12 hours per day for three months. This is often an impossible choice for patients with chronic low back pain. The statistical analysis also focused primarily on mean numerical rating pain scores rather than measuring meaningful clinical outcomes. The authors also chose to compare the mean scores between the two groups rather than focusing on the improvement caused by the intervention in individual patients.
Response since publication
A multisociety statement, multiple articles and several letters to the editor of The Journal of the American Medical Association have recently been published, pointing out several flaws in the MINT (minimal interventional treatments for participants with chronic low back pain) trials. Radiofrequency ablation is one of the most well validated interventional pain techniques that can provide meaningful pain relief to many patients with chronic pain when performed accurately in a carefully chosen patient population. There are several high-quality data validating this procedure and clinicians must not deprive patients of this valuable treatment citing flawed studies such as the MINT trials.