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CC BY-NC-ND 4.0 · Indian J Radiol Imaging
DOI: 10.1055/s-0045-1811937
Technical Reports

Treatment of Osteoid Osteoma: How to Optimize Impedance during Radiofrequency Ablation

Ibrahim Kanbour 
1   Department of Musculoskeletal Radiology, The Royal Orthopedic Hospital, Birmingham, United Kingdom
,
Kieran Howard 
1   Department of Musculoskeletal Radiology, The Royal Orthopedic Hospital, Birmingham, United Kingdom
,
Rajesh Botchu 
1   Department of Musculoskeletal Radiology, The Royal Orthopedic Hospital, Birmingham, United Kingdom
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Abstract

Introduction

Osteoid osteomas (OOs) are benign bone lesions that predominantly affect young individuals and are characterized by persistent, nocturnally exacerbated pain, which typically responds to nonsteroidal anti-inflammatory drugs (NSAIDs). While traditional surgical excision was once the standard treatment, percutaneous CT-guided radiofrequency ablation (RFA) has emerged over the past decades as the preferred minimally invasive approach.

Objectives

This article explores the technical aspects of RFA in OO treatment, with a particular focus on the challenges posed by elevated impedance during the procedure and strategies for optimization.

Materials and Methods

The RFA procedure involves precise CT-guided placement of an RF electrode within the nidus, followed by thermal ablation at 90°C for 5 to 6 minutes. Procedural technical success is determined by achieving effective coagulation necrosis, indicated by stable impedance values (350–400 ohms) and the occurrence of a “roll-off” effect, as set by the manufacturer. However, abnormally high impedance can hinder energy delivery, compromising treatment efficacy.

Results

Elevated impedance commonly arises due to electrode misplacement, contact with cortical bone or the sclerotic rim of the OO, or tissue charring around the electrode tip. Strategies to mitigate these issues include meticulous electrode positioning, incremental energy delivery, continuous temperature monitoring, and techniques such as repositioning the electrode, cleaning or replacing the radiofrequency system, “overdrilling,” or saline injection to enhance conductivity.

Conclusion

Managing impedance variations is crucial for optimizing technical RFA outcomes in OO treatment. By understanding and addressing impedance-related challenges, interventional radiologists can improve procedural success, minimize complications, and enhance patient outcomes in this minimally invasive approach.

Keywords

osteoid osteoma - radiofrequency ablation - impedance

Data Availability Statement

Data are available to share on request.


Patient's Consent

Consent to participate was obtained.




Publication History

Article published online:
16 September 2025

© 2025. Indian Radiological Association. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/)

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