1. Copyright restrictions may apply JAMA Facial Plastic Surgery Journal Club Slides: Mandibular Osteotomies & Distraction Osteogenesis Saman M, Abramowitz JM, Buchbinder D. Mandibular osteotomies and distraction osteogenesis: evolution and current advances. JAMA Facial Plast Surg. 2013;15(3):167-173.

2. Copyright restrictions may apply Introduction Although a number of mandibular and occlusal problems may be addressed by orthodontic treatment alone, dentofacial osteotomies are often needed to achieve desired functional or cosmetic results. The goal of surgical mandibular modification procedures is to correct a variety of craniofacial abnormalities for both functional and aesthetic purposes. Multiple techniques of both mandibular osteotomy and distraction osteogenesis have proven to be effective. Their effectiveness and utility are primarily determined by the specific craniofacial defect and desired outcome.

3. Copyright restrictions may apply Purpose To review the history and evolution of mandibular osteotomies and distraction and to discuss indications, advantages, and disadvantages of several techniques as well as recent advances.

4. Copyright restrictions may apply Relevance to Clinical Practice In addition to the aesthetic dysharmony, bony jaw irregularities, whether congenital, traumatic, or ablative, may lead to functional difficulties with mastication, airway, and speech as well as temporomandibular joint dysfunction. Although a number of issues may be addressed by orthodontic treatment, in more severe cases dentofacial osteotomies are often used to mobilize bony segments of the jaws to achieve desired functional or cosmetic results. In its evolution, many osteotomy techniques have been described in an effort to maximize desired results and minimize untoward effects. The number of indications for dentofacial osteotomies has grown as our understanding and techniques are expanded and refined.

5. Copyright restrictions may apply Description of Evidence This review was conducted by an analysis of the literature on mandibular osteotomy and distraction. Review articles as well as original case reports were included.

6. Copyright restrictions may apply Description of Evidence Summary of Surgeons and Their Contributions to Mandibular Osteotomies Discussed in This Article

7. Copyright restrictions may apply Controversies and Consensus Mandibular distraction involves using inductive bone generation instead of bone grafts. Distraction procedures have the advantage of being less invasive with minimal dissection and blood loss and obviate the need for internal fixation. Drawbacks of the procedure include the need for a second operation to remove the distractor as well as occlusal asymmetry from incorrect distractor angle.

8. Copyright restrictions may apply Controversies and Consensus Craniofacial microsomia is the most common indication for unilateral distraction. Pierre Robin sequence is the most common indication for bilateral distraction. Unilateral distraction is most commonly used for facial aesthetics, with better correction in asymmetry and retrognathia, correction of slanted lip commissure, and improvement of the mandibular occlusal plane. Bilateral distraction is most commonly used for Pierre Robin sequence as well as cases of respiratory compromise or obstructive sleep apnea.

9. Copyright restrictions may apply Controversies and Consensus With regard to the specific osteotomy technique for distraction, the oblique angle cut is the most commonly used approach. The oblique angle allows placement of the distractor in a horizontal or oblique plane. Its main disadvantage is the obliteration of the gonial angle. The vertical cut, which is most commonly seen in bilateral distraction procedures, allows lengthening of the mandible with a horizontal vector, which seems to be effective for patients with retrognathic or micrognathic mandibles as well as for relieving obstruction of the airway. The main disadvantage of the vertical cut is a higher risk of relapse in patients with high-angle class II malocclusion.

10. Copyright restrictions may apply Comment Recent Advances and Future Directions in Mandibular Distraction Indigenous transport distractors, which are preformed, intraoral bone- anchored devices, avoid many of the complications of external devices, such as infection and scars. –Found to be effective in a dog model. Another area of recent increase in research is in the use of biological modifiers to improve the effectiveness of distraction. –Significant increase found in the bone mineral density of the distraction when supplemented with nerve growth factor in a rabbit model. –One study demonstrated radiographically approximately half the consolidation time in mandibular distraction in a dog model using an implant of bone morphogenetic protein modified mesenchymal stem cells vs the control graft or no graft groups.

11. Copyright restrictions may apply Comment Motorized distractors are being studied as well. –Only the external device allows the clinician to adjust the rate and rhythm once distraction has begun. –Progress could not be measured without radiographic imaging. Spring-assisted distractors have a variety of confounding variables, such as specific elasticity and force of each individual spring. –Distraction was found to be inconsistent and decreased with time. Hydraulics allow the physician to measure daily force and make adjustments as necessary, but the current models were not accurate in distraction.

12. Copyright restrictions may apply Conclusions The mandibular osteotomy has evolved significantly over the past 200 years and has led to the development of mandibular distraction osteogenesis. Use of mandibular distraction osteogenesis requires excellent patient compliance, still carries significant risk, and must be fine-tuned. Research is under way for the development of less bulky and automated continuous distraction devices. Ultimately, given the variety of devices and techniques available, it is crucial for the surgeon to use treatment that is best suited for the individual patient.

13. Copyright restrictions may apply Contact Information If you have questions, please contact the corresponding author: –Masoud Saman, MD, Department of Otolaryngology–Head and Neck Surgery, The New York Eye and Ear Infirmary, 310 E 14 th St, New York, NY 10003 (saman@theidealface.com). Conflict of Interest Disclosures None reported.