title: Monopolar radiofrequency use in deep gluteal space endoscopy: sciatic nerve safety and fluid temperature.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the temperature at the sciatic nerve when using a monopolar radiofrequency (RF) probe to control bleeding in deep gluteal space endoscopy, as well as assess the fluid temperature profile.
  
  
  METHODS
  Ten hips in 5 fresh-frozen human cadaveric specimens from the abdomen to the toes were used for this experiment. Temperatures were measured at the sciatic nerve after 2, 5, and 10 seconds of continuous RF probe activation over an adjacent vessel, a branch of the inferior gluteal artery. Fluid temperatures were then measured at different distances from the probe (3, 5, and 10 mm) after 2, 5, and 10 seconds of continuous probe activation. All tests were performed with irrigation fluid flow at 60 mm Hg allowing outflow.
  
  
  RESULTS
  After 2, 5, or 10 seconds of activation over the crossing branch of the inferior gluteal artery, the mean temperature increased by less than 1°C on the surface and in the perineurium of the sciatic nerve. Considering the fluid temperature profile in the deep gluteal space, the distance and duration of activation influenced temperature (P < .05). Continuous delivery of RF energy for 10 seconds caused fluid temperature increases of 1.2°C, 2°C, and 3.1°C on average at 10 mm, 5 mm, and 3 mm of distance, respectively.
  
  
  CONCLUSIONS
  This study found the tested monopolar RF device to be safe during use in vessels around the sciatic nerve after 2, 5, and 10 seconds of continuous activation. The maximum fluid temperature (28°C) after 10 seconds of activation at 3 mm of distance is lower than the minimal reported temperature necessary to cause nerve changes (40°C to 45°C).
  
  
  CONCLUSIONS
  Monopolar RF seems to be safe to the neural structures when used at more than 3 mm of distance and with less than 10 seconds of continuous activation in deep gluteal space endoscopy with fluid inflow and outflow.
authors.affiliation: Baylor University Medical Center, Dallas, Texas, U.S.A.. Electronic address: haldavidmartin@yahoo.com.
authors.forename: Hal David
authors.initials: HD
authors.lastname: Martin
authors.affiliation: Baylor University Medical Center, Dallas, Texas, U.S.A.
authors.forename: Ian James
authors.initials: IJ
authors.lastname: Palmer
authors.affiliation: Hospital de Clínicas da Universidade Federal do Paraná, Curitiba, Brazil.
authors.forename: Munif
authors.initials: M
authors.lastname: Hatem
mesh_terms: D001182:Arthroscopy / Q000379:methods*; D001826:Body Fluids / Q000528:radiation effects*; D002081:Buttocks / Q000528:radiation effects / Q000601:surgery*; D002102:Cadaver; D006801:Humans; D011846:Radio Waves / Q000009:adverse effects*; D000078702:Radiofrequency Therapy; D012584:Sciatic Nerve / Q000503:physiopathology* / Q000528:radiation effects*; D013696:Temperature