title: The use of frozen autogenous bone flaps in delayed cranioplasty revisited.
abstract: OBJECTIVE
  To reevaluate the use of frozen autogenous bone flaps for patients undergoing delayed cranioplasty.
  
  
  METHODS
  In the past 12 years, 49 patients have undergone delayed cranioplasty using frozen autogenous bone flaps. Bone flaps removed during the initial operation were sealed in three sterilized vinyl bags and stored at -35 degrees C (n = 37) or -84 degrees C (n = 12) for 4 to 168 days (mean, 50.6 d). The bone flaps were thawed at room temperature and replaced in their original positions. After cranioplasty, we monitored resorption of the bone flaps with computed tomography and evaluated the clinical and aesthetic results. Follow-up periods ranged from 14 to 147 months (mean, 59.2 mo).
  
  
  RESULTS
  For 47 patients (95.9%), there were no complications during the follow-up period; there was slight thinning of the bone flap in some cases, but clinical and aesthetic results were highly satisfactory. Resorption was observed for a 12-year-old boy who had undergone cranioplasty, using two pieces of bone flap, 66 days after the initial operation. A 14-year-old boy with a cerebral contusion experienced a bone flap infection. Both patients underwent a second cranioplasty procedure, with ceramic plates.
  
  
  CONCLUSIONS
  The clinical and aesthetic results of delayed cranioplasty using frozen autogenous bone flaps were satisfactory. The most important factor for success was excellent contiguity between the flap and the bone edge.
authors.affiliation: Department of Neurosurgery, Gifu University School of Medicine, Gifu, Japan. tiwama@cc.gifu-u.ac.jp
authors.forename: Toru
authors.initials: T
authors.lastname: Iwama
authors.forename: Jun
authors.initials: J
authors.lastname: Yamada
authors.forename: Syu
authors.initials: S
authors.lastname: Imai
authors.forename: Jun
authors.initials: J
authors.lastname: Shinoda
authors.forename: Takashi
authors.initials: T
authors.lastname: Funakoshi
authors.forename: Noboru
authors.initials: N
authors.lastname: Sakai
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016025:Bone Transplantation / Q000009:adverse effects*; D001927:Brain Diseases / Q000000981:diagnostic imaging / Q000601:surgery*; D002648:Child; D002675:Child, Preschool; D015925:Cryopreservation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D017060:Patient Satisfaction; D011183:Postoperative Complications; D019651:Plastic Surgery Procedures / Q000009:adverse effects*; D012189:Retrospective Studies; D012886:Skull / Q000000981:diagnostic imaging / Q000601:surgery*; D013524:Surgical Flaps / Q000009:adverse effects*; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D014182:Transplantation, Autologous / Q000009:adverse effects