title: The interaction between the composition of preinjected fluids and duration of radiofrequency on lesion size.
abstract: BACKGROUND
  Clinical recommendations for the duration of radiofrequency (RF) delivery have been based on no-fluid design, which may not be representative of clinical practice where fluid preinjection occurs. The purpose of this study was to examine the interaction between the preinjection of fluids of differing compositions and duration of RF on lesion size. The variability of lesion development under different preinjection conditions was also examined across the RF lesion duration.
  
  
  METHODS
  Monopolar RF was performed with ex vivo chicken samples for 180 seconds without fluid preinjection or with fluid preinjected. Nonionic and ionic fluids were investigated. Lesion size parameters and and power levels were measured every 10 seconds. The surface area and efficiency index were calculated.
  
  
  RESULTS
  The preinjection of specific fluid increased the maximum mean surface area. Lesion growth continued throughout the entire lesion cycle. When all groups were considered together, the largest mean surface area occurred at 180 seconds. The preinjection of specific fluids altered the rate of lesion growth and the time required to achieve maximum lesion size in a fluid-specific manner. Significant variability was documented in the rate and amount of lesion growth under each condition. Extending lesioning time resulted in reduced lesion variability.
  
  
  CONCLUSIONS
  Fluid preinjection alters both final lesion size and the time required to achieve maximum lesion size. Extending the duration of RF lesion cycle beyond 90 seconds when fluid is preinjected allows for lesion size to be maximized while limiting lesion size variability, both of which assist in successfully lesioning a targeted nerve.
authors: From the *Pain Diagnostics and Interventional Care, Sewickley; and †Center of Life, Pittsburgh, PA.
authors: David A
authors: DA
authors: Provenzano
authors: Tyler W
authors: TW
authors: Watson
authors: David L
authors: DL
authors: Somers
mesh_terms: D000779:Anesthetics, Local / Q000008:administration & dosage; D000818:Animals; D002645:Chickens; D004307:Dose-Response Relationship, Radiation; D005440:Fluid Therapy / Q000379:methods*; D008012:Lidocaine / Q000008:administration & dosage; D018482:Muscle, Skeletal / Q000528:radiation effects; D061208:Pulsed Radiofrequency Treatment / Q000009:adverse effects* / Q000379:methods*; D011846:Radio Waves; D013696:Temperature; D014867:Water
chemical_list: D000779:Anesthetics, Local; D014867:Water; D008012:Lidocaine