title: Nasal reconstruction using an osteoconductive collagen gel matrix.
abstract: BACKGROUND
  Congenital malformations, granulomatous diseases, and trauma can all cause destruction of the nasal structural framework, resulting in functional nasal obstruction and altered facial cosmesis. Current methods of nasal reconstruction include cartilaginous and bony grafts, Silastic implants, and homograft only materials. However, these techniques have significant functional and cosmetic drawbacks and are not risk free. Native, isotonic, neutral-pH, space-filling type I collagen gels have been shown to mediate total repair of critical-size collagen grafts provide a framework for rapid intramembranous ossification and osteoconduction of bone from the perimeter of a defect, resulting in total bony coverage.
  
  
  OBJECTIVE
  To evaluate a novel approach to nasal reconstruction using a major defect of the bony nasal dorsum with a type I collagen gel matrix.
  
  
  METHODS
  Sixteen retired male breeder Sprague-Dawley rats were divided into control and experimental groups. The nasal bones were exposed through a dorsal incision and completely removed with a bone-cutting drill to the level of the mucosal membranes of the nasal vestibule. Defects in the experimental animals were then implanted with 200 micrograms of type I collagen gel, with control animals receiving no inlay. After 6 weeks, the animals were examined with three-dimensional computed tomography before necropsy, at which time the defects were photographed, measured by planimetry, and sectioned for histologic analysis.
  
  
  RESULTS
  Experimental defects were observed to manifest 100% surface area healing with a thin layer of bone using a type I collagen gel osteoconductive implant for nasal reconstruction. Conversely, control animals showed only a 5.7% (+/- 3.7% SD) healing by area. Histologic sections of the collagen gel implant revealed restoration of the anatomy with a thin plate of immature bone spanning the defect in continuity with the cartilage of the nasal septum and with apparent preservation of maxillonasalis suture lines.
  
  
  CONCLUSIONS
  Native, isotonic, neutral-pH, space-filling collagen gels positively influenced the repair of large nasal defects, which showed minimal bone closure in untreated animals. Their use in this role merits further investigation.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, University of Virginia Medical Center, Charlottesville, USA.
authors.forename: W H
authors.initials: WH
authors.lastname: Lindsey
authors.forename: R C
authors.initials: RC
authors.lastname: Ogle
authors.forename: R F
authors.initials: RF
authors.lastname: Morgan
authors.forename: R W
authors.initials: RW
authors.lastname: Cantrell
authors.forename: T M
authors.initials: TM
authors.lastname: Sweeney
mesh_terms: D000818:Animals; D003094:Collagen / Q000627:therapeutic use*; D000013:Congenital Abnormalities / Q000473:pathology / Q000601:surgery; D004341:Drug Evaluation; D005782:Gels; D008297:Male; D009666:Nose / Q000002:abnormalities*; D009667:Nose Deformities, Acquired / Q000473:pathology / Q000601:surgery*; D016348:Osseointegration; D051381:Rats; D017207:Rats, Sprague-Dawley; D012225:Rhinoplasty / Q000379:methods*; D014184:Transplantation, Homologous; D014945:Wound Healing
chemical_list: D005782:Gels; D003094:Collagen