Use of the polymer graft could provide a non-invasive and inexpensive method for filling gaps in the spine left after the removal of tumors (Credit: American Chemical Society).
Removing spinal tumors can be problematic, with the current options for bridging the gap left by the procedure being either very expensive, or extremely invasive. New research could provide a better solution, with the potential to use an expanding polymer implant to fill the gaps after surgery.
When a metastatic spinal tumor is removed, significant amounts of bone and entire intervertebral discs are often removed. The resulting space has to be filled in order to protect the spinal cord and maintain the strength of the spine, but current techniques for doing so are far from ideal.
Surgeons are generally faced with two options. They can either open the patient’s chest cavity to insert metal cages or bone grafts, or make an incision into the posterior or back, using small, expandable titanium rods to bridge the gap in the spine. The first option is extremely invasive, while the second is expensive, due to the high cost of the materials involved.
The new research might provide doctors with a third, more palatable option. The graft, developed by scientists at the Mayo Clinic in Minnesota, is put in place in the same way that titanium rods are inserted in currently treatments – through a small incision on the patient’s back or posterior – but makes use of much cheaper materials.
The new implant is made from a biocompatible, hydrophilic polymer, which is crosslinked to create a hollow cage. Filled with stabilizing materials and therapeutic drugs, the graft can be inserted into the body, expanding as it takes on fluid, and ultimately filling the void left by the tumor-removal surgery.
The team spent a great deal of time perfecting the expansion properties of the device, making sure that it grows fast enough so as not to require unnecessarily lengthy operations, but slow enough to give surgeons enough time to properly place the graft. The information was gathered by observing the polymer grafts under conditions that mimic those found in the body, while altering the diameter of the scaffold mold, as well as the molecular weight and charge of the material.
The scientists plan to continue their research on the new treatment, working first with cadavers to accurately simulate the implant at work. The team is aiming to conduct a clinical trial with the next few years.
