title: Percutaneous intracerebral navigation by duty-cycled spinning of flexible bevel-tipped needles.
abstract: BACKGROUND
  Intracerebral drug delivery using surgically placed microcatheters is a growing area of interest for potential treatment of a wide variety of neurological diseases, including tumors, neurodegenerative disorders, trauma, epilepsy, and stroke. Current catheter placement techniques are limited to straight trajectories. The development of an inexpensive system for flexible percutaneous intracranial navigation may be of significant clinical benefit.
  
  
  OBJECTIVE
  Utilizing duty-cycled spinning of a flexible bevel-tipped needle, the authors devised and tested a means of achieving nonlinear trajectories for the navigation of catheters in the brain, which may be applicable to a wide variety of neurological diseases.
  
  
  METHODS
  Exploiting the bending tendency of bevel-tipped needles due to their asymmetry, the authors devised and tested a means of generating curvilinear trajectories by spinning a needle with a variable duty cycle (ie, in on-off fashion). The technique can be performed using image guidance, and trajectories can be adjusted intraoperatively via joystick. Fifty-eight navigation trials were performed during cadaver testing to demonstrate the efficacy of the needle-steering system and to test its precision.
  
  
  RESULTS
  The needle-steering system achieved a target acquisition error of 2 ± 1 mm, while demonstrating the ability to reach multiple targets from one burr hole using trajectories of varying curvature.
  
  
  CONCLUSIONS
  The accuracy of the needle-steering system was demonstrated in a cadaveric model. Future studies will determine the safety of the device in vivo.
authors.affiliation: Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA. enghja@upmc.edu
authors.forename: Johnathan A
authors.initials: JA
authors.lastname: Engh
authors.forename: Davneet S
authors.initials: DS
authors.lastname: Minhas
authors.forename: Douglas
authors.initials: D
authors.lastname: Kondziolka
authors.forename: Cameron N
authors.initials: CN
authors.lastname: Riviere
mesh_terms: D002102:Cadaver; D016503:Drug Delivery Systems / Q000295:instrumentation* / Q000379:methods*; D004867:Equipment Design / Q000295:instrumentation* / Q000379:methods*; D006801:Humans; D009339:Needles