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Development of new treatment for fragility fracture using new bioabsorbable materials

  • School of Medicine/Graduate School of Medicine
  • Department of Hand Surgery

Takanobu Nishizuka [Assistant Professor]

http://meidai-seikei.jp/group/tenogeka

  • School of Medicine/Graduate School of Medicine
  • Department of Hand Surgery

Hitoshi Hirata [Professor]

Outline of Seeds

Polyhydroxyalkanoates (PHAs) are polyesters that microorganisms can use to store energy. They can also be mass-produced using genetic recombination technology, which makes them different from other bioabsorbable materials. Because living things are constantly changing shape due to circulation, body movement, and so on, medical materials demand a high level of shape conformity, something that is lacking in for the most part in the materials currently in use. Of the polyhydroxyalkanoates, the monomer 4-hydroxybutyrate (4-HB) in particular demonstrates ample stretchability, and our team has established a technique for synthesizing a PHA that includes numerous highly elastic 4-HB monomersone that shows great promise for widespread development in future healthcare applications.
Compression fractures of the spine affect an estimated million people annually in Japan, and are particularly common among the elderly. Balloon kyphoplasty, a minimally invasive treatment that allows patients to get out of bed and moving around much sooner, has become increasingly popular since 2012, when insurance plans began covering it. According to the literature, however, CT scans reveal that some 60% of patients have cement leakage outside the vertebral body, and severe complications have been reported from PMMA cement, including pulmonary embolism, making it a difficult and risky procedure. Our device injects the cement into a PHA bag with the capability to stretch to 400% its original size, and it is set up so that cement seeps through the surface of the inflated bag as a result of the injection pressure. The result is reliable, risk-free filling of cement material, fundamentally resolving the problem with the current method.

Novelty and originality of this research

Conventional kyphoplasty is a process that requires two steps. First, the balloon is expanded to create space inside the vertebral body suffering the compression fracture. Then, once the balloon is removed, cement is injected into the space. Because our method replaces the balloon with bioabsorbable material, there is no need to remove it, reducing the process to just one step. Furthermore, solid bonding with bone is achieved because the pressurized injection of the cement does not leak, but rather seeps in appropriate amounts through the surface of the PHA balloon. And, because the PHA has the ability to stretch to 400%, even if the shape inside the vertebral body suffering the compression fracture is complex, the cement injected into the PHA balloon will freely mold to that shape, filling in the cavity.

Application and research area for Industry collaboration

We are planning to study the effectiveness of our method on large animals as a way of treating vertebral compression fractures

Key Takeaway

PHA is a bioabsorbable polymer that demonstrates ample stretchability and shows great promise for widespread development in future healthcare applications. We are currently seeking out companies who are interested in designing and producing devices that use PHA to treat compression fractures.

Keywords

PHA, bioabsorbable material, compression fracture

Technologies

  • PHA production techniques

Patents

  • Bone filling material and kit for the preparation of the same, WO 2008026596 A1
  • Three-dimensional structure created from material comprising polyhydroxyalkanoate, kit for preparing bone filling material, and intramedullary nail, WO 2013146788 A1
  • Bone defect filling material, and production method therefor, WO 2015005205 A1

Monographs, Papers and Articles

  • Novel intramedullary-fixation technique for long bone fragility fractures using bioresorbable materials. Nishizuka T, Kurahashi T, Hara T, Hirata H, Kasuga T. PLoS One 2014;9(8):e104603.
  • Enhancing the mechanical properties of calcium phosphate cements using short-length polyhydroxyalkanoate fibers. Ogasawara T, Sawamura T, Maeda H, Obata A, Hirata H, Kasuga T. Journal of the Ceramic Society of Japan. Vol.124 (2016) p. 180-183