Bone Plates 
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Conventional bone plate used to repair jaw fracture
Bone plates are surgical tools, which are used to assist in the healing of broken and fractured bones. The breaks are first set and then held in place using bone plates in situations where casts cannot be applied to the injured area. Bone plates are often applied to fractures occurring to facial areas such the nose, jaw or eye sockets. Repairs like this fall into an area of medicine known as osteosynthesis.
Currently osteotemy equipment is made primarily of titanium and stainless steel. The broken bones are first surgically reset into their proper position. Then a plate is screwed onto the broken bones to hold them in place, while the bone heals back together. This method has been proven both successful and useful in treating all manner of breaks, however there are still some drawbacks. After initially placing the plate on the break or fracture the bones are compressed together and held under some slight pressure, which helps to speed up the healing process of the bone. Unfortunately, after only a couple of days the tension provided by the steel plate is lost and the break or fracture is no longer under compression, slowing the healing process.

Typical Osteosynthesis tools

Bone plates can also be fabricated using shape memory alloys, in particular nickel titanium. Using a bone plate made out of NiTi, which has a transformation temperature of around Af much greater than 15 C surgeons follow the same procedure as is used with conventional bone plates. The NiTi plates are first cooled to well below their transformation temperature, then they are placed on the set break just like titanium plates. However, when the body heats the plate up to body temperature the NiTi attempts to contract applying sustained pressure on the break or fracture for far longer than stainless steel or titanium. This steady pressure assists the healing process and reduces recovery time. There are still some problems to consider before NiTi bone plates will become commonplace. Designing plates to apply the appropriate amount of pressure to breaks and fractures is the most important difficulty, which must be overcome.

Example of how even a badly fractured face can be reconstructed using bone plates

Pictures on this page from: Atlas of Craniomaxillofacial Osteosynthesis: Miniplates, Microplates and Screws by Hacle et. al., Thieme NY 1995

  2001 SMA/MEMS Research Group 
 Last modified: Aug 17, 2001