Determination of drill paths for percutaneous cochlear access accounting for target positioning error

Jack H. Noble, Frank M. Warren, Robert F. Labadie, Benoit Dawant, J. Michael Fitzpatrick

Research output: Chapter in Book/Report/Conference proceedingConference contribution

17 Scopus citations


In cochlear implant surgery an electrode array is permanently implanted to stimulate the auditory nerve and allow deaf people to hear. Current surgical techniques require wide excavation of the mastoid region of the temporal bone and one to three hours time to avoid damage to vital structures. Recently a far less invasive approach has been proposed-percutaneous cochlear access, in which a single hole is drilled from skull surface to the cochlea. The drill path is determined by attaching a fiducial system to the patient's skull and then choosing, on a pre-operative CT, an entry point and a target point. The drill is advanced to the target, the electrodes placed through the hole, and a stimulator implanted at the surface of the skull. The major challenge is the determination of a safe and effective drill path, which with high probability avoids specific vital structures-the facial nerve, the ossicles, and the external ear canal-and arrives at the basal turn of the cochlea. These four features lie within a few millimeters of each other, the drill is one millimeter in diameter, and errors in the determination of the target position are on the order of 0.5mm root-mean square. Thus, path selection is both difficult and critical to the success of the surgery. This paper presents a method for finding optimally safe and effective paths while accounting for target positioning error.

Original languageEnglish (US)
Title of host publicationMedical Imaging 2007
Subtitle of host publicationVisualization and Image-Guided Procedures
EditionPART 2
StatePublished - 2007
Externally publishedYes
EventMedical Imaging 2007: Visualization and Image-Guided Procedures - San Diego, CA, United States
Duration: Feb 18 2007Feb 20 2007

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
NumberPART 2
ISSN (Print)1605-7422


OtherMedical Imaging 2007: Visualization and Image-Guided Procedures
Country/TerritoryUnited States
CitySan Diego, CA


  • Cochlear implant
  • Image-guided surgery
  • Monte Carlo
  • Percutaneous access

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Atomic and Molecular Physics, and Optics
  • Radiology Nuclear Medicine and imaging


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