"Pig Tail" technique in intradiscal electrothermal therapy.

To describe a new method of catheter insertion in intradiscal electrothermal therapy, which eliminates the need for reinsertion of the cannula and catheter from the contralateral side in those patients in whom optimal positioning is not achieved with the standard technique. This new technique has not been described before. In those patients in whom adequate catheter position cannot be achieved with the standard technique, instead of withdrawing the cannula after the initial treatment, we recommend rotating the cannula 180 degrees through its long axis. This will allow the catheter to hit the anterior anulus and deflect backwards toward the cannula. It can then be negotiated across the midline to adequately thermally treat the whole posterior anulus. We have performed our technique in 42 consecutive patients in whom initial navigation was difficult. This new method proved to be simple and did not cause patients additional discomfort. The "pig tail" technique is safe and effective in intradiscal electrothermal therapy of those patients with difficult navigation. It avoids the need for second needle insertion, therefore avoiding the use of more local anesthesia, further discomfort for the patient, and additional radiographic exposure.

High-intensity zone, intradiscal electrothermal therapy, and magnetic resonance imaging.

Magnetic resonance imaging changes to the symptomatic intervertebral disc following intradiscal electrothermal therapy were determined in this prospective study. Magnetic resonance images before the intradiscal electrothermal therapy procedure were compared with those taken at 6 months postprocedure in 10 patients. The presence and absence of high-intensity zone, the disc height and hydration, and Modic changes were determined from the images. In six of the 10 patients, a high-intensity zone was present on the magnetic resonance images of the disc before the intradiscal electrothermal therapy procedure. In all six patients, a high-intensity zone was still present after the procedure. In all 10 patients, there were no changes to other disc parameters assessed. Our findings question the clinical relevance of the high-intensity zone. They also suggest that the main mechanism of action of intradiscal electrothermal therapy may be other than that of sealing the anular tear.