Bone Mineralization and Spinal Fusion Evaluation of a Truss-based Interbody Fusion Device: Ovine Finite Element Analysis with Confirmatory In Vivo Outcomes.
Spine (Phila Pa 1976)
; 47(7): E319-E327, 2022 04 01.
Article
em En
| MEDLINE
| ID: mdl-34593736
ABSTRACT
STUDY DESIGN:
Finite element analysis (FEA) and in vivo ovine spinal interbody fusion study.OBJECTIVE:
To determine comparative load-induced strain amplitudes, bone mineralization and fusion outcomes associated with different diameter struts in a truss-based interbody fusion device. SUMMARY OF BACKGROUND DATA Additive manufacturing technology has been employed to develop implants that actively participate in the fusion process. The truss device enables the optimal transfer of compressive and tensile stresses via the struts. Mechanobiologic principles postulate that strut diameter can be regulated to allow different magnitudes of strain distribution within the struts which may affect fusion rates.METHODS:
Modeling of strain distributions as a function of strut diameter (0.75, 1.0, 1.25, and 1.5âmm) employed FEA that simulated physiologic loading conditions. A confirmatory in vivo ovine lumbar spinal interbody fusion study compared fusion scores and bone histomorphometric variables for cages with 0.75 and 1.5âmm strut diameters. Outcomes were compared at 3-, 6-, and 12-month follow-up intervals.RESULTS:
FEA showed an inverse association between strut diameter and peak strain amplitude. Cages with 1.0, 1.25, and 1.5âmm struts had peak strain values that were 36%, 60%, and 73% lower than the 0.75âmm strut strain value. In vivo results showed the mean fusion score for the 0.75âmm diameter strut cage was significantly greater by 3-months versus the 1.5âmm strut cage, and remained significantly higher at each subsequent interval (Pâ<â0.001 for all comparisons). Fusion rates were 95%, 100%, and 100% (0.75âmm) and 72.7%, 86.4%, and 95.8% (1.5âmm) at 3, 6, and 12âmonths. Thinner struts had greater mineralized bone tissue and less fibrous/chondral tissue than the thicker struts at each follow-up.CONCLUSION:
Validating FEA estimates, cages with smaller diameter struts exhibited more rapid fusion consolidation and more aggressive osseointegration compared with cages with larger diameters struts.Level of Evidence 4.
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Base de dados:
MEDLINE
Assunto principal:
Fusão Vertebral
Idioma:
En
Ano de publicação:
2022
Tipo de documento:
Article