title: Fluoroscopically based drilling of the femoral head in a model of adiposis.
abstract: OBJECTIVE
  Exact drilling into the ischemic areas of necrotic lesions of the femoral head remains a challenging procedure, particularly in obese patients. This study was conducted to evaluate the precision of fluoroscopically based drilling and the associated radiation exposure in an in-vitro model of adiposis.
  
  
  METHODS
  In an in-vitro model of necrotic lesions in adiposis, 20 sawbones were drilled under the guidance of an intraoperative navigation system (VectorVision, BrainLAB, Munich, Germany) and 20 more were drilled conventionally under fluoroscopic control only.
  
  
  RESULTS
  A statistically significant difference was found with respect to the distance from the drill tip to the desired mid-point of the lesion, with a mean distance of 0.56 mm for the navigated group and 1.15 mm for the control group. Furthermore, a significant difference was found in the number of drilling corrections required, as well as the radiation exposure time: The navigated group required a mean of 0.35 second drillings or corrections of the drilling direction, compared to 2.45 for the control group, and the duration of radiation exposure was less than 1 second for the navigated group and 3.85 seconds for the control group.
  
  
  CONCLUSIONS
  Drilling guided by the VectorVision navigation system shows high precision, even under difficult circumstances such as those encountered in adiposis, with a marked reduction in the duration of radiation exposure.
authors.affiliation: Orthopaedic Clinic and Polyclinic of the University of Regensburg, Regensburg, Germany. j.beckmann@asklepios.com
authors.forename: Johannes
authors.initials: J
authors.lastname: Beckmann
authors.forename: Juergen
authors.initials: J
authors.lastname: Goetz
authors.forename: Lars
authors.initials: L
authors.lastname: Perlick
authors.forename: Christian
authors.initials: C
authors.lastname: Luring
authors.forename: Joachim
authors.initials: J
authors.lastname: Grifka
authors.forename: Markus
authors.initials: M
authors.lastname: Tingart
mesh_terms: D050154:Adiposity / Q000502:physiology; D005269:Femur / Q000601:surgery*; D005271:Femur Head Necrosis / Q000601:surgery*; D005471:Fluoroscopy / Q000295:instrumentation* / Q000379:methods; D006801:Humans; D066298:In Vitro Techniques; D007511:Ischemia / Q000601:surgery*; D008954:Models, Biological; D009765:Obesity / Q000503:physiopathology*; D010020:Osteonecrosis / Q000601:surgery*; D010865:Pilot Projects; D025321:Surgery, Computer-Assisted / Q000295:instrumentation*