RT Journal Article
SR Electronic
T1 An Ex Vivo Comparison of Cooled-Radiofrequency and Bipolar-Radiofrequency Lesion Size and the Effect of Injected Fluids
JF Regional Anesthesia & Pain Medicine
JO Reg Anesth Pain Med
FD BMJ Publishing Group Ltd
SP 312
OP 321
DO 10.1097/AAP.0000000000000090
VO 39
IS 4
A1 Ricardo Vallejo
A1 Ramsin Benyamin
A1 Dana M. Tilley
A1 Courtney A. Kelley
A1 David L. Cedeño
YR 2014
UL http://rapm.bmj.com/content/39/4/312.abstract
AB Background and Objectives Radiofrequency (RF) neuroablation is a common therapy for alleviating chronic pain. Larger lesion volumes lead to higher chance of ablating small sensory nerves; therefore, bipolar-RF and cooled-RF are improved alternatives to conventional monopolar-RF. This work provides an ex vivo comparison of bipolar-RF to cooled-RF lesioning in the presence of bone structure using some conventional temperature and time programs and in conjunction with injection of a variety of clinically used substances.Methods Studies were performed using chicken muscle near a bone structure. Cooled-RF was applied using standard parameters at 60°C for 150 seconds and perpendicular to the bone. Bipolar-RF was applied using interelectrode distances (IEDs) of 5, 10, or 15 mm at 80°C for 90 or 150 seconds with the electrodes positioned either paralleled between the bone and muscle or perpendicular to the bone.The effect of injection of various fluids (sterile water, 0.9% saline, 7.3% saline, 2% lidocaine, 0.25% bupivacaine, lidocaine/methylprednisolone (Depo-Medrol), or lidocaine/betamethasone (Celestone) on lesion size was compared with no fluid injected in the muscle. Temperature profiles of lesioning were also obtained using an infrared camera.Results The volume of bipolar-RF lesions is dependent on IED, being more favorable at IED equals 10 mm. The injection of some fluids induces significant (P < 0.05) changes in bipolar-RF lesion volume, although the changes are dependent on IED. Cooled-RF induces larger lesions than bipolar-RF, with no changes in volume induced by injecting fluids.Conclusions Cooled-RF yields larger lesions than bipolar-RF under the conditions used in this study. The spherical shape of cooled-RF lesions provides larger volume coverage than lesions obtained with bipolar-RF at IED equals 5, 10, or 15 mm under similar electrode tip temperature and lesioning time.