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Osseodensification drilling vs conventional manual instrumentation technique for posterior lumbar fixation: Ex-vivo mechanical and histomorphological analysis in an ovine model.

  • Torroni, Andrea1
  • Lima Parente, Paulo Eduardo2
  • Witek, Lukasz3, 4
  • Hacquebord, Jacques Henri5, 6
  • Coelho, Paulo G1, 3, 6
  • 1 Hansjörg Wyss Department of Plastic Surgery, New York University School of Medicine, New York, New York.
  • 2 Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania.
  • 3 Department of Biomaterials, New York University College of Dentistry, New York, New York.
  • 4 Department of Biomedical Engineering, New York University Tandon School of Engineering, Brooklyn, New York.
  • 5 Department of Orthopedic Surgery, New York University School of Medicine, New York, New York.
  • 6 Department of Mechanical and Aerospace Engineering, New York University Tandon School of Engineering, Brooklyn, New York.
Published Article
Journal of Orthopaedic Research®
Wiley (John Wiley & Sons)
Publication Date
Jul 01, 2021
DOI: 10.1002/jor.24707
PMID: 32369220


Lumbar fusion is a procedure associated with several indications, but screw failure remains a major complication, with an incidence ranging 10% to 50%. Several solutions have been proposed, ranging from more efficient screw geometry to enhance bone quality, conversely, drilling instrumentation have not been thoroughly explored. The conventional instrumentation (regular [R]) techniques render the bony spicules excavated impractical, while additive techniques (osseodensification [OD]) compact them against the osteotomy walls and predispose them as nucleating surfaces/sites for new bone. This work presents a case-controlled split model for in vivo/ex vivo comparison of R vs OD osteotomy instrumentation in posterior lumbar fixation in an ovine model to determine feasibility and potential advantages of the OD drilling technique in terms of mechanical and histomorphology outcomes. Eight pedicle screws measuring 4.5 mm × 45 mm were installed in each lumbar spine of eight adult sheep (four per side). The left side underwent R instrumentation, while the right underwent OD drilling. The animals were killed at 6- and 12-week and the vertebrae removed. Pullout strength and non-decalcified histologic analysis were performed. Significant mechanical stability differences were observed between OD and R groups at 6- (387 N vs 292 N) and 12-week (312 N vs 212 N) time points. Morphometric analysis did not detect significant differences in bone area fraction occupancy between R and OD groups, while it is to note that OD showed increased presence of bone spiculae. Mechanical pullout testing demonstrated that OD drilling provided higher degrees of implant anchoring as a function of time, whereas a significant reduction was observed for the R group. © 2020 Orthopaedic Research Society. Published by Wiley Periodicals LLC.

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