title: Promoting fusion in minimally invasive lumbar interbody stabilization with low-dose bone morphogenic protein-2--but what is the cost?
abstract: BACKGROUND
  Using bone morphogenic protein (BMP) to augment fusion in spine surgery is widespread and lends itself in particular to minimally invasive lumbar fusion, where the surface area for fusion is significantly less than the equivalent open procedure.
  
  
  OBJECTIVE
  Here we described the use of very low-dose BMP in promoting fusion in minimally invasive lumbar interbody fixation but also highlight some of the potential complications of BMP-2 use and techniques available to reduce or avoid them.
  
  
  METHODS
  Prospective observational study of consecutive patients undergoing minimally invasive lumbar interbody fusion with percutaneous pedicle screws.
  
  
  METHODS
  Thirty patients aged between 22 and 78 years (mean 53 years).
  
  
  METHODS
  Thin-slice lumbar computed tomography scanning with multiplanar reconstruction at 6 and 12 months postoperative.
  
  
  METHODS
  Thirty-six spinal levels were instrumented in total, of which four underwent posterior lumbar interbody fusion and 32 underwent transforaminal lumbar interbody fusion. Bone graft harvested locally was placed in the disc space with low-dose BMP-2 (1.4 mg per level).
  
  
  RESULTS
  Thirty-three of 36 spinal levels showed complete fusion at a mean postoperative scan time of 7.1 months. Two levels demonstrated partial fusion at 6 months, which was complete at 12 months. There was one case of nonunion at 12 months, which also demonstrated vertebral body osteolysis. Despite very low-dose BMP-2, two cases of asymptomatic heterotopic ossification were observed, and there were two cases of perineural cyst formation, one of whom required revision of the interbody cage.
  
  
  CONCLUSIONS
  The use of BMP with autograft in the disc space during minimally invasive lumbar interbody fusion is associated with a high rate of early fusion. Even with very low-dose BMP used in this study, complications related to BMP usage were not avoided completely.
authors.affiliation: Academic Surgery Unit, Cambridge University Hospitals NHS Foundation Trust, Hills Rd, Cambridge CB2 2QQ, United Kingdom. richard.mannion@nhs.net
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Mannion
authors.forename: Adrian M
authors.initials: AM
authors.lastname: Nowitzke
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Wood
mesh_terms: D000328:Adult; D000368:Aged; D055396:Bone Morphogenetic Protein 2 / Q000009:adverse effects*; D003560:Cysts / Q000139:chemically induced / Q000453:epidemiology / Q000473:pathology; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae; D008297:Male; D008875:Middle Aged; D009999:Ossification, Heterotopic / Q000139:chemically induced / Q000453:epidemiology / Q000473:pathology; D010014:Osteolysis / Q000139:chemically induced / Q000453:epidemiology / Q000473:pathology; D011183:Postoperative Complications / Q000139:chemically induced / Q000453:epidemiology / Q000473:pathology*; D011994:Recombinant Proteins / Q000009:adverse effects; D013123:Spinal Fusion / Q000009:adverse effects / Q000379:methods*; D016212:Transforming Growth Factor beta / Q000009:adverse effects*; 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