Application of 3D head mold planning and individualized templates in mandibular distraction

Objective To investigate the applications of preoperative 3D head modeling and individualized template guiding in mandibular distraction and to evaluate the effect postsurgery.Methods 10 patients with mandibular micrognathia,who developed moderate to severe OSAHS were selected.All patients underwent mandibular distraction.3D head models were printed based on spiral CT data.Preoperative simulations of osteotomy and distractor placement were done with the 3D head models,and accordingly,individualized templates were fabricated.During surgery,the templates guided the position of osteotomy line and placement of distractors.The distraction begun 5 ～ 7 days after operation at a frequency of 1 mm/day.After distraction,the distractors were maintained for 3～6 months till removed.Results All 10 cases were treated successfully.Average operation time was (1.6 ± 1.3) h.The mean distraction distance was (23.6 ± 7.5) mm.The preoperative polysomnography showed an apnea-hypopnea index of (37.1 ± 13.7) per hour and a lowest oxygen saturation of (75.2 ± 18.4)％.Postoperative polysomnography showed improvement that apnea-hypopnea index changed to (2.7 ± 4.8) per hour and lowest oxygen saturation to (92.1 ± 5.3)％.No complication occurred during treatment.Conclusions The preoperative simulations show excellent guides during surgery,which will improve surgical precision,shorten the operation time,avoid injury of important anatomical structures,reduce operation difficulties and minimize possible risks. Key words: Micrognathia;  Obstructive sleep apnea-hypopnea syndrome;  3D printing