The treatment goal of HFM is to attain a good facial profile without the loss of function. The severity of the temporomandibular joint (TMJ) complex deformity is the main factor influencing its reconstruction, which involves TMJ reconstruction, costochondral grafts, maxillary osteotomy, mandibular osteotomy, application of bone grafts, and distraction osteogenesis of the mandible [5,8,13–17]. Surgery, before skeletal maturity, is necessary for preventing secondary growth deformities and for cosmetic correction . In general, the treatment protocol in these patients is a two-stage process, comprising DO during pubertal growth followed by a secondary orthognathic surgery at the end of pubertal growth.
DO is a technique by which a new bone is formed between the surfaces of 2 bone segments as a result of the tension that is created by the gradual movement of the two segments in the opposite direction, thereby lengthening the original bone structure . This technique was first described in 1905 by Codivilla who performed osteotomies and elongated femur bones by gradual distraction . It was later popularized by Ilizarov in 1951 by the elongation of the upper and lower limbs; since then, this technique has undergone several developments.
In 1973, Snyder reported mandibular lengthening by gradual distraction in animal models . Mandibular lengthening by gradual distraction in a human mandible was first performed in 1992 by McCarthy, with the aid of an extraoral device in a patient with HFM . Since then, it has been applied to bones of individuals with craniofacial deformities, and several studies have reported the use of this treatment, resulting in the development of an effective device.
Kim et al.  reported the effectiveness of a new DO protocol for over-distraction following compressive stimulation against the conventional DO protocol. Another study by Kim et al.  examined the expression of TGF-ß1, osteonectin, and BMP-4 in mandibular distraction osteogenesis with compression stimulation; the expression levels of TGF-ß1, osteonectin, and BMP-4 on DO with a compression force during early consolidation were increased, illustrating the effect of compression force during DO. Therefore, we applied a new DO protocol for over-distraction with compressive forces on this patient.
The DO method with compression force used in the present study is different from other conventional DO techniques because of the extended amount of distraction obtained, and the interventional as well as intermittent compression force applied during the early period of consolidation [11,12]. In the present study, after DO, vertical discrepancy had improved and the deviation of mandible was corrected to the normal midline position. The patient was treated by DO with compression force, due to which the consolidation period was shortened to 6 weeks. In general, facial skeleton growth is almost complete after the pubertal growth period. In the present study, orthognathic surgery was planned as a second stage treatment option. The patient presented with HFM type 2a, and owing to the absence of temporomandibular joint problems and the presence of mild facial asymmetry, an advanced, sliding genioplasty and left mandibular body, inferior border augmentation was planned, with the simultaneous use of a PPE implant. Mandibular body augmentation using a PPE implant is a simplified method, instead of an autograft, and provides satisfactory esthetic results by reinforcing the buccal width as well as the length of the inferior border of mandible. After the second operation, the patient’s facial profile was visibly improved. Further, periodic, close observation has been advised for this patient to assess the fate of the PPE implant. If facial asymmetry recurs, a free tissue composite flap transfer or iliac bone graft will be applied to the affected side of the face.