title: Endoscopic assisted resection of prepontine epidermoid cysts.
abstract: OBJECTIVE
  To describe an innovative endoscopic technique to treat prepontine epidermoid cysts. These cysts are typically resected in a microsurgical fashion and can be associated with significant risks and complications. This report is the first description of an endoscopic-assisted removal of an epidermoid cyst without the use of the operative microscope and evaluates the operative findings, technique, and postoperative course.
  
  
  METHODS
  Retrospective review at tertiary referral center.
  
  
  METHODS
  Two patients, one with rapidly progressive headache and ataxia, and another with trigeminal neuralgia were found to have mixed-intensity cystic lesions of the prepontine region consistent with an epidermoid cyst. A detailed description of the preoperative preparation, surgical approach, intraoperative technique, pre- and post-operative imaging findings and monitoring outcomes are emphasized.
  
  
  RESULTS
  Both patients underwent resection of the epidermoid cyst using an endoscope-assisted technique. The procedures were 3 and 4 hours in duration with an estimated blood loss of 50 cc in both operations. No intraoperative complications occurred. The patients were discharged from the hospital on postoperative days 2 and 3, respectively. Postoperative imaging revealed no edema of the cerebellum and complete resolution of the cyst. Neurological examination revealed improvement of preoperative symptoms with complete resolution of headache and ataxia of case 1, with resolution of trigeminal neuralgia in case 2. Case 2 did develop an ipsilateral cranial nerve (CN) VI paresis postoperatively that resolved over a 3-week period. The patient from case 1 remains symptom free after 24-months with magnetic resonance imaging (MRI) consistent with gross-total resection of the epidermoid cyst. Case 2 has continued resolution of trigeminal neuralgia and CN VI palsy with 12-month follow-up MRI consistent with gross total resection.
  
  
  CONCLUSIONS
  The use of the endoscope as the sole means to access the posterior fossa to treat prepontine cystic lesions affords the surgeon excellent visualization with minimal cerebellar retraction and can be done in a safe and effective manner with little to no morbidity.
authors.affiliation: Section of Neurosurgery, St. John Providence Hospital & Medical Centers, Michigan State University, Southfield, Michigan, United States.
authors.forename: Joshua
authors.initials: J
authors.lastname: Krass
authors.affiliation: Department of Neurotology, Michigan Ear Institute, Southfield, Michigan, United States.
authors.forename: Yoav
authors.initials: Y
authors.lastname: Hahn
authors.affiliation: Section of Neurosurgery, St. John Providence Hospital & Medical Centers, Michigan State University, Southfield, Michigan, United States.
authors.forename: Kristophe
authors.initials: K
authors.lastname: Karami
authors.affiliation: Department of Neurotology, Michigan Ear Institute, Southfield, Michigan, United States.
authors.forename: Seilesh
authors.initials: S
authors.lastname: Babu
authors.affiliation: Department of Neurosurgery, Oakland University William Beaumont School of Medicine, Auburn Hills, Michigan, United States.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Pieper
mesh_terms: D001927:Brain Diseases / Q000601:surgery*; D003388:Cranial Fossa, Posterior / Q000601:surgery*; D004814:Epidermal Cyst / Q000601:surgery*; D006801:Humans; D008297:Male; D008866:Microsurgery / Q000379:methods*; D008875:Middle Aged; D044583:Neuroendoscopy / Q000379:methods*; D012189:Retrospective Studies; D016896:Treatment Outcome