US patent granted for UCT’s maxillofacial distractor

UCT was recently granted a US patent for its maxillofacial distractor, a medical device for the reconstruction of the human upper jaw (maxilla). This device has been jointly invented by A/Prof George Vicatos of Mechanical Engineering, Dr Rushdi Hendricks who is a maxillofacial surgeon in private practice, and James Boonzaier while studying at UCT. Dr Hendricks recently completed a PhD related to this work.

Transport Distraction Osteogenesis (TDO) is a specialist method of facial reconstruction that differs from other facial reconstruction techniques such as bone grafting.  Bone grafting involves implantation of bone into the area that is to be reconstructed, whereas TDO is method whereby existing bone is very slowly pulled by a distractor to encourage stem cell differentiation and ultimately the formation of new bone and tissue in the affected area. The major advantage of TDO over bone grafting is that it allows regeneration of not only bone, but also soft tissue and blood supply.

There are many distractors available on the market for reconstruction of the lower jaw (mandible), but not many distractors have been designed for the maxilla. It is not just a simple solution of using the mandibular distraction devices and turning them upside down or back to front. These devices cannot be used for the same purposes that they are designed for in the maxilla, firstly because the nature of the bone is different and the anatomical constraints to be found in the maxilla are very different to that of the mandible.

The re-creation of a palatal vault, alveolar bone as well as a vestibule by distraction osteogenesis is indeed a difficult task to achieve, therefore, it took the inventors a significant amount of time to design and develop the correct dimensions and temperament of the device in order to arrive at the correct design for the maxilla.

What makes this invention new and inventive, and therefore patentable, is that it consists of a track that has a flat rectangular cross-sectional shape that is capable of forming sharp bends. The track holds a carriage that is movable along the track and attached to the bone or tissue that is to be distracted. 

The device can be customized and used on a range of curved trajectories as may be encountered when performing distraction osteogenesis in the maxilla. It is capable of anterior-to-posterior distraction along a patient specific curvilinear geometry for repair of segmental defects of the maxilla that are larger than 20 mm and up to 100mm. Mandible distractors, on the other hand, are only able to distract linearly and over short distances.

The team has successfully used the device to regenerate 45 mm of maxillary alveolar bone in a period of 28 days in a completed clinical case study.

Click on the following link to see a YouTube video detailing the innovation.

https://www.youtube.com/watch?v=-HSImGyk2fU