We evaluated the efficacy of Escherichia
coli-derived recombinant human bone morphogenetic protein-2
(E-BMP-2) in a mini-pig model of spinal anterior interbody fusion.
A total of 14 male mini-pigs underwent three-level anterior lumbar
interbody fusion using polyether etherketone (PEEK) cages containing
porous hydroxyapatite (HA). Four groups of cages were prepared:
1) control (n = 10 segments); 2) 50 μg E-BMP-2 (n = 9); 3) 200 μg
E-BMP-2 (n = 10); and 4) 800 μg E-BMP-2 (n = 9). At eight weeks
after surgery the mini-pigs were killed and the specimens were evaluated
by gross inspection and manual palpation, radiological evaluation
including plain radiographs and micro-CT scans, and histological
analysis. Rates of fusion within PEEK cages and overall union rates
were calculated, and bone formation outside vertebrae was evaluated.
One animal died post-operatively and was excluded, and one section
was lost and also excluded, leaving 38 sites for assessment. This
rate of fusion within cages was 30.0% (three of ten) in the control
group, 44.4% (four of nine) in the 50 μg E-BMP-2 group, 60.0% (six
of ten) in the 200 μg E-BMP-2 group, and 77.8% (seven of nine) in
the 800 μg E-BMP-2 group. Fusion rate was significantly increased
by the addition of E-BMP-2 and with increasing E-BMP-2 dose (p =
0.046). In a mini-pig spinal anterior interbody fusion model using
porous HA as a carrier, the implantation of E-BMP-2-loaded PEEK
cages improved the fusion rate compared with PEEK cages alone, an
effect that was significantly increased with increasing E-BMP-2
dosage.
Cite this article: Bone Joint J 2013;95-B:217–23.
