title: Patient-specific polymethylmethacrylate prostheses for secondary reconstruction of large calvarial defects: A retrospective feasibility study of a new intraoperative moulding device for cranioplasty.
abstract: OBJECTIVE
  The aim of this study was to review a new template-based technique for intraoperative patient-specific cranioplasty manufacturing (PSCM) with polymethylmethacrylate (PMMA) to cover large calvarial defects.
  
  
  METHODS
  A polypropylene foil thermoformed on a three-dimensional reprint of the calvarial defect was used as an intraoperative moulding device for PMMA between August 2012 and December 2015. Surgical and radiological data were retrospectively reviewed, and a patient questionnaire was used to assess functional and cosmetic outcome (numeric rating scale, Odom's criteria).
  
  
  RESULTS
  Seventeen patients (mean age 42.2 ± 14.5 years) received PSCM. Operating time averaged 130 ± 34 min, and the approximate blood loss was 293 ± 185 ml. Volumetric analysis revealed a lower implant volume compared to index bone (mean 66.5 vs. 72 cm3, p = 0.513), the mean difference in thickness being the lowest in the posterior parietal and pterional (0.4-0.7 mm) and the highest in the anterior-superior frontal area (1.8 mm). Cosmetic satisfaction averaged 9 ± 1.5, with 70.6% of patients judging the overall result as excellent or good and 29.4% as satisfactory. Mean follow-up was 19.5 ± 13.3 months, with an overall complication rate of 17.6%, including 11.8% surgical site infections (SSIs) and one implant removal.
  
  
  CONCLUSIONS
  Intraoperative PSCM using PMMA moulded on a thermoformed polypropylene foil leads to satisfactory outcomes. It is a safe technique with complication rates comparable but not superior to those of other alloplastic techniques, but the device has considerable production costs.
authors.affiliation: Department of Neurosurgery (Head: A. Weyerbrock), Cantonal Hospital St. Gallen, Rorschacher Strasse 95, 9007 St. Gallen, Switzerland. Electronic address: moser.manuel@gmx.at.
authors.forename: Manuel
authors.initials: M
authors.lastname: Moser
authors.affiliation: Department of Neurosurgery (Head: A. Weyerbrock), Cantonal Hospital St. Gallen, Rorschacher Strasse 95, 9007 St. Gallen, Switzerland.
authors.forename: Raphael
authors.initials: R
authors.lastname: Schmid
authors.affiliation: Department of Neurosurgery (Head: A. Weyerbrock), Cantonal Hospital St. Gallen, Rorschacher Strasse 95, 9007 St. Gallen, Switzerland.
authors.forename: Ralf
authors.initials: R
authors.lastname: Schindel
authors.affiliation: Department of Neurosurgery (Head: A. Weyerbrock), Cantonal Hospital St. Gallen, Rorschacher Strasse 95, 9007 St. Gallen, Switzerland.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Hildebrandt
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001860:Bone Plates; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007432:Intraoperative Period; D008297:Male; D008875:Middle Aged; D019904:Polymethyl Methacrylate / Q000627:therapeutic use*; D011474:Prosthesis Design / Q000295:instrumentation / Q000379:methods; D019651:Plastic Surgery Procedures / Q000295:instrumentation / Q000379:methods*; D012189:Retrospective Studies; D012886:Skull / Q000601:surgery*; D055815:Young Adult
chemical_list: D019904:Polymethyl Methacrylate
keywords: CAD/CAM; CranioTool™; Cranioplasty; PMMA; Patient-specific