Effect of recombinant human bone morphogenetic protein-2 in an experimental model of spinal fusion in a radiated area

Document Type

Article

Abstract

Study Design. An animal model of posterolateral intertransverse process spine fusion was used. Objectives. To investigate whether recombinant human bone morphogenetic protein-2 (rhBMP-2) can overcome the adverse effects of radiation treatment (RT) on spine fusion. Summary of Background Data. Spinal metastases are common. Some of these patients are candidates for spinal cord decompression and vertebral reconstruction; however, radiation has significant adverse effects on bone healing. Methods. A posterolateral fusion model was used with rhBMP-2 or iliac crest bone graft (ICBG). Eighty one-year-old rabbits were divided into eight groups: 1) RT 14 days before surgery, rhBMP-2; 2) RT 14 days before surgery, ICBG; 3) RT 2 days after surgery, rhBMP-2; 4) RT 2 days after surgery, ICBG; 5) RT 14 days after surgery, rhBMP-2; 6) RT 14 days after surgery, ICBG; 7) no RT, rhBMP-2; 8) no RT, ICBG. Animals were killed approximately 35 days after surgery. Manual palpation was the definitive test of fusion. Biomechanical and histologic assessments were also performed. Results. All rhBMP-2 groups had significantly greater fusion rates versus respective ICBG control groups: 1 (86%) versus 2 (0%) (P = 0.005), 3 (100%) versus 4 (0%) (P < 0.0001), 5 (100%) versus 6 (0%) (P < 0.0001), and 7 (100%) versus 8 (60%) (P = 0.003). Stiffness and ultimate strength did not differ significantly between the experimental and control groups. Histologic assessment confirmed new bone formation in the fusion masses from rhBMP-2 groups. Conclusions. Use of rhBMP-2 produced a significantly greater rate of fusion compared with ICBG in a previously radiated area in an animal model, without the morbidity of ICBG harvesting and without the risk of inadvertently using autograft contaminated by micrometastases. ©2005, Lippincott Williams & Wilkins, Inc.

Keywords

Bone morphogenetic protein, Pseudoarthrosis, Rabbit, Radiation therapy, Recombinant human bone morphogenetic protein-2, Spine fusion, Spine instrumentation, Spine metastasis

Publication Date

12-1-2005

Publication Title

Spine

ISSN

03622436

E-ISSN

15281159

Volume

30

Issue

23

First Page

2585

Last Page

2592

PubMed ID

16319743

Digital Object Identifier (DOI)

10.1097/01.brs.0000188294.01845.20

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