title: Cranioplasty after decompressive craniectomy: is there a rationale for an initial artificial bone-substitute implant? A single-center experience after 631 procedures.
abstract: OBJECTIVE
  The complication rate for cranioplasty after decompressive craniectomy is higher than that after other neurosurgical procedures; aseptic bone resorption is the major long-term problem. Patients frequently need additional operations to remove necrotic bone and replace it with an artificial bone substitute. Initial implantation of a bone substitute may be an option for selected patients who are at risk for bone resorption, but this cohort has not yet been clearly defined. The authors' goals were to identify risk factors for aseptic bone flap necrosis and define which patients may benefit more from an initial bone-substitute implant than from autograft after craniectomy.
  
  
  METHODS
  The authors retrospectively analyzed 631 cranioplasty procedures (503 with autograft, 128 with bone substitute) by using a stepwise multivariable logistic regression model and discrimination analysis.
  
  
  RESULTS
  There was a significantly higher risk for reoperation after placement of autograft than after placement of bone substitute; aseptic bone necrosis (n = 108) was the major problem (OR 2.48 [95% CI1.11-5.51]). Fragmentation of the flap into 2 or more fragments, younger age (OR 0.97 [95% CI 0.95-0.98]; p < 0.001), and shunt-dependent hydrocephalus (OR 1.73 [95% CI1.02-2.92]; p = 0.04) were independent risk factors for bone necrosis. According to discrimination analysis, patients younger than 30 years old and older patients with a fragmented flap had the highest risk of developing bone necrosis.
  
  
  CONCLUSIONS
  Development of bone flap necrosis is the main concern in long-term follow-up after cranioplasty with autograft. Patients younger than 30 years old and older patients with a fragmented flap may be candidates for an initial artificial bone substitute rather than autograft.
authors.affiliation: Departments of 1 Neurosurgery and.
authors.forename: Falko
authors.initials: F
authors.lastname: Schwarz
authors.affiliation: Departments of 1 Neurosurgery and.
authors.forename: Pedro
authors.initials: P
authors.lastname: Dünisch
authors.affiliation: Departments of 1 Neurosurgery and.
authors.forename: Jan
authors.initials: J
authors.lastname: Walter
authors.affiliation: Anaesthesiology and Intensive Care, Jena University Hospital-Friedrich Schiller University Jena, Germany.
authors.forename: Yasser
authors.initials: Y
authors.lastname: Sakr
authors.affiliation: Departments of 1 Neurosurgery and.
authors.forename: Rolf
authors.initials: R
authors.lastname: Kalff
authors.affiliation: Departments of 1 Neurosurgery and.
authors.forename: Christian
authors.initials: C
authors.lastname: Ewald
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D018786:Bone Substitutes; D001930:Brain Injuries / Q000150:complications / Q000473:pathology / Q000601:surgery*; D056424:Decompressive Craniectomy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019651:Plastic Surgery Procedures; D012086:Reoperation; D012189:Retrospective Studies; D013524:Surgical Flaps; D055815:Young Adult
chemical_list: D018786:Bone Substitutes
keywords: IQR = interquartile range; NPV = negative predictive value; PEEK = polyetheretherketone; PPV = positive predictive value; SAH = subarachnoid hemorrhage; aseptic bone flap necrosis; autograft; bone resorption; bone substitute; cranioplasty; trauma