Bio-Expandable Bone Graft Could Help Spinal Surgery Patients

An expandable, biodegradable graft could help metastatic spinal tumor patients recover from the surgical removal of bone segments and intervertebral discs, according to a new study.

Researchers at the Mayo Clinic (Rochester, MN, USA) have developed a biodegradable, hydrophilic, polymer graft that when surgically placed in the damaged vertebrae, expands to precisely fill the resected areas by absorbing bodily fluids. The graft is composed of two sections; a hollow hydrophilic scaffold made of crosslinked oligo(poly(ethylene glycol) fumarate) (OPF), and a stabilized polymer filler material. To develop the graft, the researchers first identified a combination of materials that are biocompatible in animals, and which they believe will work in humans.

To control the kinetics of the polymer graft expansion, the researchers made chemical changes to the filler to modify the degree and timing of the expansion, under conditions that mimicked the spinal column environment. The modulation of the molecular weight and charge of the polymer enabled them to tune the material’s properties so that the expansion rate was slow enough to enable surgeons to place it correctly, but fast enough so that it did not extend surgery times. The study was presented at the 251st national meeting & exposition of the American Chemical Society (ACS), held during March 2016 in San Diego (CA, USA).

“The overall goal of this research is to find ways to treat people with metastatic spinal tumors; the spine is the most common site of skeletal metastases in cancer patients, but unlike current treatments, our approach is less invasive and is inexpensive,” said lead author and study presenter Lichun Lu, PhD. “When we designed this expandable tube, we wanted to be able to control the size of the graft so it would fit into the exact space left behind after removing the tumor.”

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