Effects of Anesthetic Fluid Injectates on Lesion Sizes in Cooled Radiofrequency Ablation.
METHODS
Nonrandomized trial.


OBJECTIVE
This is an ex vivo study using pork chops to simulate human vertebra to determine the effects of various anesthetic fluids injectates and concentrations on lesion size and shape created when using cooled radiofrequency ablation. Secondary objective is to determine the effects of various time durations of applied lesion on lesion size created. Our final objective is to determine the effects of fluid injectates on tissue temperature and impedance.


BACKGROUND
Radiofrequency neurotomy is a therapeutic procedure involving ablation of sensory afferent nerves to the vertebral zygapophyseal joints. Larger lesions increase the likelihood the target nerve is ablated.


METHODS
Before cooled radiofrequency ablation, tissue was injected with either 0.9% normal saline, 1% lidocaine, 2% lidocaine, 0.25% bupivacaine, 0.5% bupivacaine, 0.75% bupivacaine, 0.2% ropivacaine, 0.5% ropivacaine, or 1% ropivacaine. Duration of cooled radiofrequency was either 45, 90, or 150 seconds.


RESULTS
There was no significant difference in the size of the lesion created when using different injectates and concentrations. There was no significant difference in the size of the lesion created when applying a 90 seconds duration lesion compared with a 150 seconds duration lesion.


CONCLUSIONS
Applying a 90 seconds duration lesion can be considered in clinical use for cooled radiofrequency ablation. The use of an injectate did not significantly alter the size or desired spherical shape of the lesion created, did not significantly alter the time required to create the lesion, and did not significantly lower the temperature threshold. The study is limited by the use of ex vivo tissue which does not account for the effects of tissue perfusion. The use of an injectate before cooled radiofrequency ablation can be made at the interventionalist's discretion.


METHODS
N/A.
Indiana University Health Pain Center, Muncie, IN.
Haibin
H
Wang
University of Pittsburgh Medical Center Department of Physical Medicine and Rehabilitation, Pittsburgh, PA.
Eric R
ER
Helm
University of Pittsburgh Medical Center Department of Physical Medicine and Rehabilitation, Pittsburgh, PA.
Herbie
H
Yung
D000777:Anesthetics / Q000494:pharmacology; D000818:Animals; D017115:Catheter Ablation / Q000379:methods; D004566:Electrodes; D004867:Equipment Design / Q000379:methods; D009336:Necrosis / Q000139:chemically induced; D011846:Radio Waves; D000069466:Red Meat; D013552:Swine; D013696:Temperature
D000777:Anesthetics