A New Vertebral Body Replacement Strategy Using Expandable Polymeric Cages

Xifeng Liu, Alex Paulsen, Hugo Giambini, Ji Guo, A. Lee Miller, Po Chun Lin, Michael J. Yaszemski, Lichun Lu

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


We have developed a novel polymeric expandable cage that can be delivered via a posterior-only surgical approach for the treatment of noncontained vertebral defects. This approach is less invasive than an anterior-only or combined approach and much more cost-effective than currently used expandable metal cages. The polymeric expandable cage is composed of oligo poly(ethylene glycol) fumarate (OPF), a hydrogel that has been previously shown to have excellent nerve and bone tissue biocompatibility. OPF hydrogel cages can expand to twice their original diameter and length within a surgical time frame following hydration. Modulation of parameters such as polymeric network crosslink density or the introduction of charge to the network allowed for precise expansion kinetics. To meet specific requirements due to size variations in patient vertebral bodies, we fabricated a series of molds with varied diameters and explored the expansion kinetics of the OPF cages. Results showed a stable expansion ratio of approximately twofold to the original size within 20 min, regardless of the absolute value of the cage size. Following implantation of a dried OPF cage into a noncontained vertebral defect and its in situ expansion with normal saline, other augmentation biomaterials, such as poly(propylene fumarate) (PPF), can be injected to the lumen of the OPF cage and allowed to crosslink in situ. The OPF/PPF composite scaffold can provide the necessary rigidity and stability to the augmented spine.

Original languageEnglish (US)
Pages (from-to)223-232
Number of pages10
JournalTissue Engineering - Part A
Issue number5-6
StatePublished - Mar 2017


  • biomaterials
  • hydrogel
  • spine
  • tissue engineering
  • vertebral body reconstruction

ASJC Scopus subject areas

  • Bioengineering
  • Biochemistry
  • Biomedical Engineering
  • Biomaterials


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