SPEAKER:
Leonard Kaban, DMD, MD; MGH, Harvard School of Dental Medicine     

MODERATOR:
Maria Troulis, DDS, MSc; MGH

(No Video Available)

SUMMARY:

Correcting the majority of congenital craniofacial defects, as well as some facial injuries resulting from trauma, requires making bones longer.  Distraction osteogenesis is a technique used to promote bone growth using the body’s innate bone-healing mechanisms.  In the procedure, a bone is cut, and the two pieces are pushed apart by a mechanical device.  As the two pieces move away from each other, new bone fills the gap.  The overlying soft tissue grows as well.

Researchers led by Dr. Leonard B. Kaban of Massachusetts General Hospital are attempting to improve the devices used to push facial bones apart in distraction osteogenesis.  Until recently, the mechanisms were external and only operated along straight lines.  Now, thanks to work done by Dr. Kaban’s team, maxillofacial surgeons can use curvilinear devices capable of moving bone in three dimensions, as opposed to one.  These new devices, however, are not perfect.  They still depend on patient caretakers reliably turning a screw at regular intervals.  The next challenge for Dr. Kaban’s group is to create devices that will move bone continuously, not in daily increments of 1 mm.  These continuously moving devices would cause less pain, wouldn’t require daily patient compliance, and might promote faster bone growth.  At the moment, researchers are testing a continuously moving device in animal models, and they have found that the device’s components are durable, that its user interface works, and that it is tolerated by the body.  When the position sensor in the device is perfected, it will be ready to use in people. 

Planning bone movement before a device is implanted is critical because no existing device is capable of changing its trajectory mid-course.  With help of a CIMIT grant, Dr. Kaban’s team has developed state-of-the-art software capable of simulating the entire process of distraction osteogenesis in the face.  Called Osteoplan, the 3-D planning tool uses data from CT scans to create a segmented model of the patient’s skull, and it then calculates the vector of movement required to achieve desirable bone positioning.  Outcome CT scans can be overlaid on the original model to assess the effectiveness of the procedure.  In the future, researchers hope that the distraction devices used in maxillofacial procedures will continue to improve, along with the corresponding software.