title: Decreased navigated drilling time using an external guide stabilising device.
abstract: BACKGROUND
  Computer navigation in orthopaedic procedures can improve accuracy and decrease radiation time compared to traditional fluoroscopy. Many different applications are now available, and drilling is commonly used amongst them. Aside from additional set up time required, the drilling procedure itself may take a significant amount of time. We hypothesised that using an external stabilising guide which can be set anywhere in space can decrease then time necessary for navigated drilling.
  
  
  METHODS
  Foam blocks, 80 mm in length and a density similar to cancellous bone, were obtained. Small discs were placed on one end as drilling targets. Using an Iso-C 3D navigation system, 20 navigated drilling trials were performed under each of two conditions: freehand, and with the use of a drill stabilising guide attached to an operating table. The time and accuracy of the two methods were compared.
  
  
  RESULTS
  The time required for the entire navigation procedure was significantly less using the stabilising arm compared to drilling freehand with navigation (4.5 min versus 5.8 min, p=0.009). There was no significant difference in accuracy between the two methods.
  
  
  CONCLUSIONS
  Using a guide which attaches to the table and allows the surgeon to fix the drill sleeve when the desired vector is chosen allows for faster navigated drilling. This was easy to set up and attach to the table, and did not diminish accuracy of drilling an intended target.
authors.affiliation: Department of Orthopaedic Surgery, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021, USA. gardnerm@hss.edu
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Gardner
authors.forename: Musa
authors.initials: M
authors.lastname: Citak
authors.forename: Daniel
authors.initials: D
authors.lastname: Kendoff
authors.forename: Tobias
authors.initials: T
authors.lastname: Hüfner
authors.forename: Christian
authors.initials: C
authors.lastname: Krettek
mesh_terms: D004867:Equipment Design; D009983:Orthopedic Equipment / Q000592:standards*; D019637:Orthopedic Procedures / Q000295:instrumentation / Q000379:methods*; D012680:Sensitivity and Specificity; D013997:Time Factors