Highlights
- •We used a newly developed, high-porosity unidirectional porous hydroxyapatite spacer for double-door laminoplasty.
- •Regenos spacers lowered the risk of dislocation after implantation and facilitated bone bonding.
- •Breakage and deformity of Regenos spacers was observed at high rates because of their insufficient mechanical strength.
Abstract
We used a newly developed, high-porosity unidirectional porous hydroxyapatite spacer
(Regenos spacer, not approved by the FDA). To assess the short-term bone bonding capacity
of Regenos spacer used in a double-door laminoplasty, including displacement, deformation,
and absorption after implantation.
Fifty patients underwent a double-door laminoplasty using Regenos spacers, with computed
tomography (CT) images obtained at 2–4 weeks and 6–12 months, post-surgery, in 30
patients. Bone bonding rate, amount of displacement, and the incidence of deformation
and absorption were evaluated from the early and late postoperative CT images.
Bone bonding rate for Regenos spacers, using our modified classification, was 48.9%
at 6 months, post- surgery, and 67.0% at 12 months. The change in anterior-posterior
diameter of the spinal canal (ΔH) was significantly greater for Regenos spacers than
for autologous bone spacers (p < 0.05). There was no difference in the change in angle
between the vertebral arch and the posterior wall of the vertebral body (ΔR) between
the Regenos and autologous bone spacers. Deformation was identified in 21.3% (10/47).
Though, no evidence of breakage along their long axis was identified among these 10
cases on axial CT images with passable clinical results.
Regenos spacers lowered the risk of early dislocation after implantation and facilitated
bone bonding due to infiltration of surrounding tissue. However, the deformation and
absorption was observed at high rates because of their insufficient mechanical strength,
we need to require a longer term follow-up to more clearly evaluate their adverse
impact in clinically.
Keywords
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Article info
Publication history
Published online: January 14, 2019
Accepted:
January 3,
2019
Received:
September 14,
2018
Identification
Copyright
© 2019 Elsevier Ltd. All rights reserved.
