title: Endoscopic approaches to brainstem cavernous malformations: Case series and review of the literature.
abstract: BACKGROUND
  Symptomatic cavernous malformations involving the brainstem are frequently difficult to access via traditional methods. Conventional skull-base approaches require significant brain retraction or bone removal to provide an adequate operative corridor. While there has been a trend toward limited employment of the most invasive surgical approaches, recent advances in endoscopic technology may complement existing methods to access these difficult to reach areas.
  
  
  METHODS
  Four consecutive patients were treated for symptomatic, hemorrhagic brainstem cavernous malformations via fully endoscopic approaches (endonasal, transclival; retrosigmoid; lateral supracerebellar, infratentorial; endonasal, transclival). Together, these lesions encompassed all three segments of the brainstem. Three of the patients had complete resection of the cavernous malformation, while one patient had stable residual at long-term follow up. Associated developmental venous anomalies were preserved in the two patients where one was identified preoperatively. Three of the four patients maintained stable or improved neurological examinations following surgery, while one patient experienced ipsilateral palsies of cranial nerves VII and VIII. The first transclival approach resulted in a symptomatic cerebrospinal fluid leak requiring re-operation, but the second did not. Although there are challenges associated with endoscopic approaches, relative to our prior microsurgical experience with similar cases, visualization and illumination of the surgical corridors were superior without significant limitations on operative mobility.
  
  
  CONCLUSIONS
  The endoscope is a promising adjunct to the neurosurgeon's ability to approach difficult to access brainstem cavernous malformations. It allows the surgeon to achieve well-illuminated, panoramic views, and by combining approaches, can provide minimally invasive access to most regions of the brainstem.
authors.affiliation: Department of Neurosurgery, Hospital of the University of Pennsylvania, 3400 Spruce Street, Silverstein Pavilion 3, Philadelphia, PA 19104.
authors.forename: Nikhil R
authors.initials: NR
authors.lastname: Nayak
authors.affiliation: Department of Neurosurgery, Hospital of the University of Pennsylvania, 3400 Spruce Street, Silverstein Pavilion 3, Philadelphia, PA 19104.
authors.forename: Jayesh P
authors.initials: JP
authors.lastname: Thawani
authors.affiliation: Department of Neurosurgery, Hospital of the University of Pennsylvania, 3400 Spruce Street, Silverstein Pavilion 3, Philadelphia, PA 19104.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Sanborn
authors.affiliation: Division of Neurosurgery, Children's Hospital of Philadelphia, 3400 Civic Center Boulevard, Wood Building, Philadelphia, PA 19104.
authors.forename: Phillip B
authors.initials: PB
authors.lastname: Storm
authors.affiliation: Department of Neurosurgery, Hospital of the University of Pennsylvania, 3400 Spruce Street, Silverstein Pavilion 3, Philadelphia, PA 19104.
authors.forename: John Y K
authors.initials: JY
authors.lastname: Lee
keywords: Brainstem; cavernoma; cavernous malformation; endoscopic; minimally invasive