The effects of dexamethasone on bone fusion in an experimental model of posterolateral lumbar spinal arthrodesis
Document Type
Article
Abstract
Object. The use of corticosteroid agents during the healing phase after spinal arthrodesis remains controversial. Although anecdotal opinion suggests that corticosteroids may inhibit bone fusion, such an effect has not been substantiated in clinical trials or laboratory investigations. This study was undertaken to delineate the effect of exogenous corticosteroid administration on bone graft incorporation in an experimental model of posterolateral lumbar fusion. Methods. An established, well-validated model of lumbar intertransverse process spinal fusion in the rabbit was used. Twenty-four adult New Zealand white rabbits underwent L5-6 bilateral posterolateral spinal fusion in which autogenous iliac crest bone graft was used. After surgery, the animals were randomized into two treatment groups: a control group (12 rabbits) that received intramuscular injections of normal saline twice daily and a dexamethasone group (12 rabbits) that received intramuscular dexamethasone (0.05 mg/kg) twice daily. After 42 days, the animals were killed and the integrity of the spinal fusions was assessed by radiography, manual palpation, and biomechanical testing. In seven (58%) of the 12 control rabbits, solid posterolateral fusion was achieved. In no dexamethasone-treated rabbits was successful fusion achieved (p = 0.003). Tensile strength and stiffness of excised spinal segments were significantly lower in dexamethasone-treated animals than in control animals (tensile strength 91.4 ± 30.6 N and 145.3 ± 48.2, respectively, p = 0.004; stiffness 31.4 ± 11.6 and 45.0 ± 15.2 N/mm, respectively, p = 0.02). Conclusions. The corticosteroid agent dexamethasone inhibited bone graft incorporation in a rabbit model of single-level posterolateral lumbar spinal fusion, inducing a significantly higher rate of nonunion, compared with that in salinetreated control animals.
Keywords
Biomechanical study, Corticosteroid therapy, Fusion rate, Posterolateral lumbar arthrodesis, Rabbit, Spinal fusion
Publication Date
1-1-2001
Publication Title
Journal of Neurosurgery
ISSN
00223085
Volume
94
Issue
1 SUPPL.
First Page
76
Last Page
81
PubMed ID
11147871
Digital Object Identifier (DOI)
10.3171/spi.2001.94.1.0076
Recommended Citation
Sawin, P. D.; Dickman, C. A.; Crawford, N. R.; Melton, M. S.; Bichard, W. D.; and Sonntag, V. K.H., "The effects of dexamethasone on bone fusion in an experimental model of posterolateral lumbar spinal arthrodesis" (2001). Translational Neuroscience. 855.
https://scholar.barrowneuro.org/neurobiology/855