title: Effect of daily parathyroid hormone (1-34) on lumbar fusion in a rat model.
abstract: BACKGROUND
  Despite numerous studies evaluating the anabolic effects of intermittent administration of parathyroid hormone (PTH) on bone, there are no published studies examining its effect on spinal fusion outcomes.
  
  
  OBJECTIVE
  To determine the effect of daily injection of human recombinant PTH(1-34) on posterolateral lumbar fusions in a rat model.
  
  
  METHODS
  Prospective, case-controlled, preclinical animal study.
  
  
  METHODS
  Manual palpation and serum osteocalcin.
  
  
  METHODS
  Single-level, intertransverse process spinal fusions were performed with iliac crest autograft in 56 Sprague-Dawley rats. Animals received daily injections of placebo or PTH(1-34). At 6 weeks, fusion masses were assessed by manual palpation. Serum osteocalcin levels were assessed in a subset of the animals.
  
  
  RESULTS
  Manual palpation revealed the control group to have a fusion rate of 37% (10/27) and the PTH(1-34)-treated group to have a fusion rate of 52% (15/29). Mean serum osteocalcin levels were 59.8 and 88.6 ng/L for the control and PTH(1-34) groups, respectively.
  
  
  CONCLUSIONS
  There was a trend towards greater fusion rate in the PTH(1-34) group as compared with the placebo group. Further, PTH(1-34) administration was associated with a significant increase in osteocalcin levels. Certainly, further investigations are warranted, as an injectable agent capable of increasing fusion rates would be of great clinical value.
authors.affiliation: Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, CT 06520-8071, USA.
authors.forename: James P
authors.initials: JP
authors.lastname: Lawrence
authors.forename: Frank
authors.initials: F
authors.lastname: Ennis
authors.forename: Andrew P
authors.initials: AP
authors.lastname: White
authors.forename: David
authors.initials: D
authors.lastname: Magit
authors.forename: Gert
authors.initials: G
authors.lastname: Polzhofer
authors.forename: Inneke
authors.initials: I
authors.lastname: Drespe
authors.forename: Nancy W
authors.initials: NW
authors.lastname: Troiano
authors.forename: Jonathan N
authors.initials: JN
authors.lastname: Grauer
mesh_terms: D000818:Animals; D005260:Female; D006801:Humans; D023421:Models, Animal; D015675:Osteocalcin / Q000097:blood; D010173:Palpation; D010281:Parathyroid Hormone / Q000494:pharmacology*; D010446:Peptide Fragments / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins / Q000494:pharmacology; D013123:Spinal Fusion
chemical_list: D010281:Parathyroid Hormone; D010446:Peptide Fragments; D011994:Recombinant Proteins; D015675:Osteocalcin