title: Advantages and limitations of endoscopic endonasal approaches to the skull base.
abstract: BACKGROUND
  The anatomy of the skull base is extremely complex with an abundance of critical neurovascular bundles and their corresponding foramina as well as the insertions and origins of multiple masticatory and craniocervical muscles. These anatomic intricacies increase the difficulty of surgery within this area.
  
  
  METHODS
  Advantages and disadvantages of endoscopic endonasal approaches (EEAs) based on the authors' sequential learning and experience are described.
  
  
  RESULTS
  EEAs offer the advantages of using preexistent air spaces that enable accessing various areas of the skull base, while avoiding external incisions or scars and obviating the need for the translocation of the maxillofacial skeleton. In addition, EEAs are well suited to preserve neurologic, visual, and masticatory functions as well as cosmesis. However, the sinonasal corridor must be expanded and optimized to access the skull base adequately, facilitate the reconstruction of the surgical defect, avoid sinonasal complications, and minimize sequelae. Important considerations can limit or indicate the approach, such as the nature of the pathology, including location, diagnosis, and vascularity; patient characteristics, including age and medical comorbidities; surgeon attributes, including training, experience, and expertise; the resultant need to reconstruct large skull base defects and feasible alternatives to do so; and institutional resources, including adjunctive services, an intensive care unit, and operating room equipment.
  
  
  CONCLUSIONS
  EEAs are important techniques in contemporary skull base surgery. Understanding the indications for and limitations of these approaches help to maximize outcomes.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Wexner Medical Center at The Ohio State University, Columbus, Ohio, USA.
authors.forename: Pornthep
authors.initials: P
authors.lastname: Kasemsiri
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Wexner Medical Center at The Ohio State University, Columbus, Ohio, USA. Electronic address: ricardo.carrau@osumc.edu.
authors.forename: Ricardo L
authors.initials: RL
authors.lastname: Carrau
authors.affiliation: Department of Neurological Surgery, Wexner Medical Center at The Ohio State University, Columbus, Ohio, USA.
authors.forename: Leo F S
authors.initials: LF
authors.lastname: Ditzel Filho
authors.affiliation: Department of Neurological Surgery, Wexner Medical Center at The Ohio State University, Columbus, Ohio, USA.
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Prevedello
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Wexner Medical Center at The Ohio State University, Columbus, Ohio, USA.
authors.forename: Bradley A
authors.initials: BA
authors.lastname: Otto
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Wexner Medical Center at The Ohio State University, Columbus, Ohio, USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: Old
authors.affiliation: Department of Neurological Surgery, Wexner Medical Center at The Ohio State University, Columbus, Ohio, USA.
authors.forename: Danielle
authors.initials: D
authors.lastname: de Lara
authors.affiliation: Department of Neurological Surgery, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Amin B
authors.initials: AB
authors.lastname: Kassam
mesh_terms: D004724:Endoscopy / Q000193:education / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D009296:Nasal Cavity / Q000601:surgery*; D019635:Neurosurgical Procedures / Q000193:education / Q000295:instrumentation / Q000379:methods*; D019291:Skull Base / Q000033:anatomy & histology / Q000601:surgery*; D016896:Treatment Outcome
keywords: Endoscopic endonasal approaches; Endoscopy; Microscopy; Skull base