title: Complications After In Vivo and Ex Vivo Autologous Bone Flap Storage for Cranioplasty: A Comparative Analysis of the Literature.
abstract: BACKGROUND
  The most common bone flap storage strategies after decompressive hemicraniectomy for malignant intracranial hypertension include freezer cryopreservation (CP) and subcutaneous abdominal implantation (AP). Numerous series have reported on patient outcomes after cranioplasty in terms of infection, cosmesis, and resorption. This meta-analysis compares published outcomes of bone flap CP and subcutaneous storage with respect to efficacy and complication risk in patients undergoing cranioplasty after hemicraniectomy.
  
  
  METHODS
  A systematic review was performed using PubMed-searchable studies that included bone flap storage methods and outcome data for cranioplasties performed between 1975 and 2015.
  
  
  RESULTS
  A total of 48 studies including 5346 patients were identified that met the inclusion criteria. Of these patients, 4096 underwent cranioplasty with an autologous flap. Mean bone flap storage times for CP and AP flaps were 69.9 and 69.7 days. Mean follow-up time for CP and AP flaps was 16.9 and 16.5 months. No statistically significant differences were found when comparing CP with subcutaneous storage of bone flaps with respect to percentage of patients developing infection (7.3% vs. 7.1%), percentage of patients needing revision surgery (15.9% vs. 7.6%), and percentage of patients experiencing resorption (9.7% vs. 7.7%).
  
  
  CONCLUSIONS
  This is the largest and most robust review comparing published outcomes of CP and subcutaneous storage of bone flaps in patients who have undergone decompressive hemicraniectomy. This review found no statistically significant differences in clinical outcomes (infection, resorption, reoperation) when comparing storage methods for bone flap preservation. This study suggests that both strategies may be used safely and successfully.
authors.affiliation: Department of Neurosurgery, University of Florida, Gainesville, Florida, USA.
authors.forename: Brian
authors.initials: B
authors.lastname: Corliss
authors.affiliation: Department of Neurosurgery, University of Florida, Gainesville, Florida, USA. Electronic address: tim.gooldy@ufl.edu.
authors.forename: Timothy
authors.initials: T
authors.lastname: Gooldy
authors.affiliation: Department of Neurosurgery, University of Florida, Gainesville, Florida, USA.
authors.forename: Sasha
authors.initials: S
authors.lastname: Vaziri
authors.affiliation: Department of Neurosurgery, University of Florida, Gainesville, Florida, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Kubilis
authors.affiliation: Department of Neurosurgery, University of Florida, Gainesville, Florida, USA.
authors.forename: Gregory
authors.initials: G
authors.lastname: Murad
authors.affiliation: Department of Neurosurgery, Wake Forest University, Winston-Salem, North Carolina, USA.
authors.forename: Kyle
authors.initials: K
authors.lastname: Fargen
mesh_terms: D056424:Decompressive Craniectomy / Q000009:adverse effects*; D006801:Humans; D011183:Postoperative Complications / Q000453:epidemiology / Q000209:etiology*; D012307:Risk Factors; D012886:Skull / Q000601:surgery*; D013524:Surgical Flaps / Q000009:adverse effects*
keywords: Autologous; Bone flap preservation; Cranioplasty; Decompressive craniectomy; Infection; Resorption; Subcutaneous