"Pig Tail" technique in intradiscal electrothermal therapy
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Updated: Sep 25, 2026

Patient-Specific Electric Field Simulation In Spinal Metastasis Electrochemotherapy
Published on: July 31, 2026
A A Narvani1, E Tsiridis, M A Ishaque
1Royal National Orthopaedics Hospital, London, UK. alinarvani@hotmail.com
Abstract:
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.
