title: Minimally invasive image-guided access for drainage of petrous apex lesions: a case report.
abstract: OBJECTIVE
  In this case report, we present a novel, minimally invasive image-guided approach to drainage of a petrous apex lesion.
  
  
  METHODS
  A 34-year-old man diagnosed with a petrous apex lesion consistent with cholesterol granuloma. The granuloma was large and caused mild compression of the brainstem with associated neurologic symptoms and seizure-like activity.
  
  
  METHODS
  Based on the anatomic location of the lesion, it was determined that the treatment plan would be to surgically drain the lesion via 2 linear paths-one after an infralabyrinthine approach and the other a subarcuate approach. Customized microstereotactic frames that mount on bone-implanted markers and constrain the drill along the desired path were used to accurately drill these desired paths and avoid damage to surrounding critical structures. After a simple mastoidectomy, the petrous apex was successfully reached without damage to vital adjacent structures by drilling the 2 linear channels using 2 custom microstereotactic frames.
  
  
  METHODS
  Viscous brown liquid and debris was recovered by irrigating through one of the channels and suctioning through the other.
  
  
  RESULTS
  Drainage of the petrous apex was successfully performed via 2 linear channels without any complications. Custom microstereotactic frames were used to accurately drill those linear channels. Postoperative CT ensured no complications. Postoperative course of the patient was remarkable with normal hearing and normal facial nerve function.
  
  
  CONCLUSIONS
  We presented a successful implementation of an image-guided approach to drain petrous apex.
authors.affiliation: *Department of Otolaryngology, Vanderbilt University Medical Center, Nashville, Tennessee; †Department of Otorhinolaryngology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma; and ‡Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, Tennessee, U.S.A.
authors.forename: Ramya
authors.initials: R
authors.lastname: Balachandran
authors.forename: Betty S
authors.initials: BS
authors.lastname: Tsai
authors.forename: Tara
authors.initials: T
authors.lastname: Ramachandra
authors.forename: Jack H
authors.initials: JH
authors.lastname: Noble
authors.forename: Benoit M
authors.initials: BM
authors.lastname: Dawant
authors.forename: Robert F
authors.initials: RF
authors.lastname: Labadie
authors.forename: Marc L
authors.initials: ML
authors.lastname: Bennett
mesh_terms: D000328:Adult; D001847:Bone Diseases / Q000150:complications / Q000473:pathology / Q000601:surgery*; D003560:Cysts / Q000601:surgery; D004322:Drainage / Q000379:methods*; D006099:Granuloma / Q000150:complications / Q000473:pathology / Q000601:surgery*; D006801:Humans; D008297:Male; D008416:Mastoid / Q000601:surgery; D019060:Minimally Invasive Surgical Procedures / Q000379:methods*; D009422:Nervous System Diseases / Q000209:etiology; D010579:Petrous Bone / Q000473:pathology / Q000601:surgery*; D016634:Radiosurgery; D012640:Seizures / Q000209:etiology; D025321:Surgery, Computer-Assisted / Q000379:methods*; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome