Novel Technique and Step-by-Step Construction of a Computer-Guided Stent for Mandibular Distraction Osteogenesis

Distraction osteogenesis is an integral part in management of mandibular defects associated with hemifacial microsomia and post-ankylotic mandibular defects. The most difficult part in distraction osteogenesis is the prediction of distraction vector and risk of injury to vital structures as inferior alveolar. The present study aimed to present 3-dimensionally constructed computer-guided splints in distraction osteogenesis to get an ideal vector and minimal risk of vital structures injury.

The technical note presents cases series of 6 patients who had computer-guided distraction osteogenesis surgery using prefabricated splints.

The distance between the virtual and physical pins and osteotomy was measured, and the deviation of the vector angle and osteotomy angle was also assessed. Average deviation in pin distance was 3 mm and in vector angle 13.5°. Average deviation in osteotomy distance was 2.6 mm and in osteotomy angle 14.4°. None of the cases had injury to vital structure. There was significant improvement (P = 0.0078) in the medial canthus-buccal commissure distance where the arithmetic mean improved from 59.6 (SD = 10.1) mm pre-distraction in the defective side to 67.1 (SD = 8) mm post-distraction. The degree of correction was 97% compared to the normal side.

3D printed surgical stents were successful in transferring the virtual treatment plan of mandibular distraction osteogenesis into the surgical theatre with an acceptable margin of error and without injury to any vital structures.