Piezoelectric composites, as well as methods of making such composites for biomedical applications.
Lower back pain is one of the major reasons for physician office visits. The most serious, persistent cases of lower back pain are often treated by spinal fusion surgery which provides stability to the spine through the fusing of adjacent vertebrae. Spinal fusion surgery is performed over 600,000 times annually. The failure rate of the surgery is 10% in healthy patients and as high as 46% in the difficult-to-fuse population, which includes smokers and diabetics.
The standard surgical protocol involves the use of a spinal fusion interbody device which is packed with bone and placed in the intervertebral space to stabilize the spine. For the difficult-to-fuse patient population, adjunct therapies have been used clinically as a supplement to the standard interbody device.The most widely used of these therapies are bone morphogenetic proteins (BMPs) and electrical stimulation. Both have proven to be effective therapies to increase the success rate of spinal fusions; however, each is hampered by limitations. Electric stimulation suffers from the need for a battery pack, and its reliance on user compliance. BMPs have also been shown to cause ectopic bone growth, which can be detrimental to patients, particularly when used in close proximity to the spinal cord and nerve roots. BMP usage is also expensive, adding thousands of dollars to the cost of an individual surgery. To improve upon these existing therapies, there is a need for a device that can increase fusion without the use of a battery pack or adjunct therapies.
Piezoelectric spinal fusion interbody device that combines the basic interbody cage that is currently used on the market with DC electrical stimulation. The piezoelectric implant produces a bone growth stimulating electric charge to the fused spinal segment when mechanically strained during dynamic loading of the spinal column.
When placed in a patient, the piezoelectric implant produces DC electrical stimulation in response to dynamic forces. The device generates and delivers electrical stimulation in response to normal patient activity. The implant safely delivers a bone-growing negative electric potential to the fusion by means of a stacked, macro fiber piezoelectric composite generator.
Composite material is tough and mechanically compatible with bone. The piezoelectric implant does not require an adjunct therapy, second surgery, or battery pack to garner the benefits of bone stimulation. The footprint of the device is the same as the standard fusion cage.
Interbody device promotes fusion without the need for adjunct therapy. DC electrical stimulation has a twenty year history of safety and effectiveness. Proof of principle study in sheep showed greater bone formation with piezo implant at both six weeks and four months than with standard cage (control).
The piezoelectric composites can be used as a platform technology that can be inserted into other implant devices for tissue and bone stimulation.