title: The case for duraplasty in adults undergoing posterior fossa decompression for Chiari I malformation: a systematic review and meta-analysis of observational studies.
abstract: BACKGROUND
  Posterior fossa decompression is carried out to improve passage of cerebrospinal fluid (CSF) in patients with symptomatic Chiari 1 malformations (CM1), but the extent and means of decompression remains controversial. Dural opening with subsequent duraplasty may contribute to clinical outcome, but may also increase complication risk. The aim of this systematic review and meta-analysis is to assess the effects of durotomy with subsequent duraplasty on clinical outcome in surgical treatment of adults with CM1.
  
  
  METHODS
  We systematically searched MEDLINE, Embase and CENTRAL, and screened references in relevant articles and in UpToDate. Publications with previously untreated adults (>15 years) with CM1 with or without associated syringomyelia, treated in the period 1990-2013 were eligible.
  
  
  METHODS
  Posterior fossa decompression with duraplasty (PFDD group) was compared to posterior fossa decompression with bony decompression alone (PFD group).
  
  
  RESULTS
  The search retrieved 233 articles. After the review we included 12 articles, but only 4 articles included posterior fossa decompression with both techniques. Only 2 out of 12 studies were prospective. The odds ratio (OR) for reoperation was 0.15 (95% CI 0.05-0.49) in the PFDD group compared to PFD (p=0.002). The OR of clinical failure at follow-up was 1.06 (95% CI 0.52-2.14) for PFDD compared to PFD (p=0.88). There was also no difference in syringomyelia improvement between techniques (p=0.60). The OR for CSF-related complications were 6.12 (95% CI 0.37-101.83) for PFDD compared to PFD (p=0.21).
  
  
  CONCLUSIONS
  This systematic review of observational studies reveals higher reoperation rates after bony decompression alone, but clinical improvement was not higher after primary decompression with duraplasty. There are so far no high-quality studies that offer guidance in the choice of decompressive technique in adult CM1 patients. We think that a randomized controlled trial on this topic is both needed and feasible.
authors.affiliation: Department of Neurosurgery, Karolinska University Hospital, Stockholm, Sweden. Electronic address: petter.forander@karolinska.se.
authors.forename: Petter
authors.initials: P
authors.lastname: Förander
authors.affiliation: Department of Ophthalmology and Neurosurgery, University Hospital of Northern Norway, Tromsø, Norway. Electronic address: Kristin.Sjavik@unn.no.
authors.forename: Kristin
authors.initials: K
authors.lastname: Sjåvik
authors.affiliation: Department of Neurosurgery, St. Olavs University Hospital, Trondheim, Norway; National Centre for Ultrasound and Image Guided Therapy, Trondheim, Norway. Electronic address: ole.solheim@ntnu.no.
authors.forename: Ole
authors.initials: O
authors.lastname: Solheim
authors.affiliation: Unit for Applied Clinical Research, Norwegian University of Science and Technology, Trondheim, Norway. Electronic address: ingrid.i.riphagen@ntnu.no.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Riphagen
authors.affiliation: Department of Neurosurgery, St. Olavs University Hospital, Trondheim, Norway; Norwegian Centre of Competence in Deep Brain Stimulation for Movement Disorders, Trondheim, Norway. Electronic address: sashagulati@hotmail.com.
authors.forename: Sasha
authors.initials: S
authors.lastname: Gulati
authors.affiliation: Unit for Applied Clinical Research, Norwegian University of Science and Technology, Trondheim, Norway. Electronic address: oyvind.salvesen@ntnu.no.
authors.forename: Øyvind
authors.initials: Ø
authors.lastname: Salvesen
authors.affiliation: Department of Neurosurgery, St. Olavs University Hospital, Trondheim, Norway; National Centre for Ultrasound and Image Guided Therapy, Trondheim, Norway; MI Lab, Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway. Electronic address: asgeir.s.jakola@ntnu.no.
authors.forename: Asgeir Store
authors.initials: AS
authors.lastname: Jakola
mesh_terms: D000328:Adult; D001139:Arnold-Chiari Malformation / Q000601:surgery*; D019299:Decompression, Surgical / Q000379:methods; D004388:Dura Mater / Q000601:surgery*; D006801:Humans; D064887:Observational Studies as Topic; D011183:Postoperative Complications; D013595:Syringomyelia / Q000150:complications; D016896:Treatment Outcome
keywords: Adult; Chiari; Duraplasty; Meta-analysis; Review