title: Endoscopic, endonasal, transclival resection of a pontine cavernoma:  case report.
abstract: BACKGROUND
  Hemorrhagic, symptomatic cavernous malformations in the brainstem are difficult to access. Conventional approaches such as the transpetrosal approach often require significant brain retraction. We present the successful purely endoscopic, endonasal, transclival resection of a symptomatic cavernoma located in the ventromedial pons.
  
  
  METHODS
  A 17-year-old male patient presented with acute onset of headache, facial numbness, and tingling. Magnetic resonance imaging demonstrated an enhancing lesion in the pons consistent with a cavernous malformation. Over the course of the next 3 weeks, the patient had 2 additional episodes of acutely worsening neurological deficits that left him with left-sided hemiparesis, a right sixth nerve palsy, and dysphagia. A purely endoscopic, endonasal, transclival approach was used to resect the cavernoma. Postoperatively, he had a transient worsening of his left-side motor function and restricted horizontal gaze, but at the last follow-up, his hemiparesis had improved and his magnetic resonance imaging demonstrated a radiographic cure. He developed a cerebrospinal fluid (CSF) leak despite prophylactic lumbar CSF drainage for 2 days and the use of bilateral vascularized nasoseptal flaps. The CSF leak was repaired with CSF diversion and a second surgical procedure; at the last follow-up, he had no recurrence of the leak.
  
  
  CONCLUSIONS
  An endoscopic, endonasal, transclival approach is a novel and effective approach to cavernous malformations presenting to the ventral surface of the pons. Recently developed techniques for closure and repair of the skull base defect have minimized but have not eliminated the risk of CSF leak in these procedures.
authors.affiliation: Department of Neurosurgery, Perelman School of Medicine, Hospital of University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA. matthew.sanborn@uphs.upenn.edu
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Sanborn
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Kramarz
authors.forename: Philip B
authors.initials: PB
authors.lastname: Storm
authors.forename: Nithin D
authors.initials: ND
authors.lastname: Adappa
authors.forename: James N
authors.initials: JN
authors.lastname: Palmer
authors.forename: John Y K
authors.initials: JY
authors.lastname: Lee
mesh_terms: D000293:Adolescent; D020295:Brain Stem Neoplasms / Q000601:surgery*; D002559:Cerebrospinal Fluid Rhinorrhea / Q000209:etiology / Q000601:surgery; D020786:Hemangioma, Cavernous, Central Nervous System / Q000601:surgery*; D006801:Humans; D008297:Male; D044583:Neuroendoscopy / Q000009:adverse effects / Q000379:methods*; D011149:Pons / Q000601:surgery*; D011183:Postoperative Complications / Q000209:etiology / Q000601:surgery