Effect of daily parathyroid hormone (1-34) on lumbar fusion in a rat model
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Published on: July 14, 2023
James P Lawrence1, Frank Ennis, Andrew P White
1Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, CT 06520-8071, USA.
Background Context:
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.
Purpose:
To determine the effect of daily injection of human recombinant PTH(1-34) on posterolateral lumbar fusions in a rat model.
Study Design:
Prospective, case-controlled, preclinical animal study.
Outcome Measures:
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.