title: Clinical validation study of percutaneous cochlear access using patient-customized microstereotactic frames.
abstract: OBJECTIVE
  Percutaneous cochlear implant (PCI) surgery consists of drilling a single trough from the lateral cranium to the cochlea avoiding vital anatomy. To accomplish PCI, we use a patient-customized microstereotactic frame, which we call a "microtable" because it consists of a small tabletop sitting on legs. The orientation of the legs controls the alignment of the tabletop such that it is perpendicular to a specified trajectory.
  
  
  METHODS
  Prospective.
  
  
  METHODS
  Tertiary referral center.
  
  
  METHODS
  Thirteen patients (18 ears) undergoing traditional cochlear implant surgery.
  
  
  METHODS
  With institutional review board approval, each patient had 3 fiducial markers implanted in bone surrounding the ear. Temporal bone computed tomographic scans were obtained, and the markers were localized, as was vital anatomy. A linear trajectory from the lateral cranium through the facial recess to the cochlea was planned. A microtable was fabricated to follow the specified trajectory.
  
  
  METHODS
  After mastoidectomy and posterior tympanotomy, accuracy of trajectories was validated by mounting the microtables on the bone-implanted markers and then passing sham drill bits across the facial recess to the cochlea. The distance from the drill to vital anatomy was measured.
  
  
  RESULTS
  Microtables were constructed on a computer-numeric-control milling machine in less than 5 minutes each. Successful access across the facial recess to the cochlea was achieved in all 18 cases. The mean +/- SD distance was 1.20 +/- 0.36 mm from midportion of the drill to the facial nerve and 1.25 +/- 0.33 mm from the chorda tympani.
  
  
  CONCLUSIONS
  These results demonstrate the feasibility of PCI access using customized microstereotactic frames.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Vanderbilt University, Nashville, Tennessee 37232, USA. robert.labadie@vanderbilt.edu
authors.forename: Robert F
authors.initials: RF
authors.lastname: Labadie
authors.forename: Ramya
authors.initials: R
authors.lastname: Balachandran
authors.forename: Jason E
authors.initials: JE
authors.lastname: Mitchell
authors.forename: Jack H
authors.initials: JH
authors.lastname: Noble
authors.forename: Omid
authors.initials: O
authors.lastname: Majdani
authors.forename: David S
authors.initials: DS
authors.lastname: Haynes
authors.forename: Marc L
authors.initials: ML
authors.lastname: Bennett
authors.forename: Benoit M
authors.initials: BM
authors.lastname: Dawant
authors.forename: J Michael
authors.initials: JM
authors.lastname: Fitzpatrick
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019929:Cochlear Implantation / Q000295:instrumentation* / Q000379:methods; D003054:Cochlear Implants; D007758:Ear, Inner / Q000000981:diagnostic imaging / Q000601:surgery*; D004867:Equipment Design; D005260:Female; D034381:Hearing Loss / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000295:instrumentation; D018579:Patient Selection; D011446:Prospective Studies; D011859:Radiography; D013238:Stereotaxic Techniques / Q000295:instrumentation*; D016896:Treatment Outcome