title: The use of allograft and recombinant human bone morphogenetic protein for instrumented atlantoaxial fusions.
abstract: BACKGROUND
  Iliac crest autograft is the historic gold standard for bone grafting, but is associated with a significant patient morbidity. Fusion rates of C1-C2 up to 88.9% using allograft and 96.7% using autologous iliac crest bone graft can be achieved when combined with rigid screw fixation. We sought to determine our fusion rate when combining allograft with recombinant human bone morphogenetic protein-2 (rh-BMP2) and rigid screw fixation.
  
  
  METHODS
  We reviewed our experience using allograft, bone morphogenetic protein (rh-BMP2) and screw fixation of C1-C2 in 52 patients and examined indications, surgical technique, fusion rates, and complications. In 28 patients, corticocancellous allograft pieces were laid along decorticated bone after a C2 neurectomy was performed. In 24 patients, unicortical iliac crest allograft was precision-cut to fit between the C1 lamina and C2 spinous processes.
  
  
  RESULTS
  Fifty-two C1-C2 fusions were performed with allograft, rh-BMP2, and rigid screw fixation. There were 25 female and 27 male patients ranging in age from 6 to 92 years (mean, 65.8 years). Operative indications included trauma (56%), degenerative disease (21%), rheumatoid arthritis (15%), congenital anomalies (6%), and synovial cyst (2%). The mean follow-up was 23.9 ± 2.1 months (range, 2-55 months). The mean dose of rh-BMP2 used for all patients was 4.5 mg (range, 2.2-12 mg). In patients who achieved sufficient follow-up, 100% achieved solid fusion: 45/50 Lenke A, 5/50 Lenke B. There were no known complications attributable to the use of rh-BMP2.
  
  
  CONCLUSIONS
  The use of small doses of rh-BMP2 added to allograft in addition to rigid screw fixation is a safe and highly effective means of promoting a solid fusion of the atlantoaxial complex and spares the patient the morbidity of iliac crest harvest.
authors: Department of Neurological Surgery and The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, Florida, USA.
authors: Brian
authors: B
authors: Hood
authors: Department of Neurosurgery, University of Maryland, Baltimore, Maryland, USA.
authors: D Kojo
authors: DK
authors: Hamilton
authors: Department of Neurological Surgery, The University of Virginia Medical Center, Charlottesville, Virginia, USA.
authors: Justin S
authors: JS
authors: Smith
authors: Department of Neurological Surgery and The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, Florida, USA.
authors: Marine
authors: M
authors: Dididze
authors: Department of Neurological Surgery, The University of Virginia Medical Center, Charlottesville, Virginia, USA.
authors: Christopher
authors: C
authors: Shaffrey
authors: Department of Neurological Surgery and The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, Florida, USA. Electronic address: ALevi@med.miami.edu.
authors: Allan D
authors: AD
authors: Levi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001174:Arthrodesis / Q000009:adverse effects / Q000379:methods*; D001268:Atlanto-Axial Joint / Q000601:surgery*; D055396:Bone Morphogenetic Protein 2 / Q000008:administration & dosage / Q000627:therapeutic use*; D016025:Bone Transplantation / Q000379:methods*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007085:Ilium / Q000637:transplantation; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000627:therapeutic use; D013123:Spinal Fusion / Q000009:adverse effects / Q000379:methods*; D016212:Transforming Growth Factor beta / Q000008:administration & dosage / Q000627:therapeutic use*; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D055396:Bone Morphogenetic Protein 2; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; C499469:recombinant human bone morphogenetic protein-2
keywords: Atlantoaxial allograft; Cervical; Fusion; rh-BMP2