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.
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Introduction
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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.
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The goal of surgical mandibular modification procedures is to correct a
variety of craniofacial abnormalities for both functional and aesthetic
purposes.
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Multiple techniques of both mandibular osteotomy and distraction
osteogenesis have proven to be effective.
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Their effectiveness and utility are primarily determined by the specific
craniofacial defect and desired outcome.
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Purpose
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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.
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Relevance to Clinical Practice
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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.
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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.
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In its evolution, many osteotomy techniques have been described in an
effort to maximize desired results and minimize untoward effects.
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The number of indications for dentofacial osteotomies has grown as our
understanding and techniques are expanded and refined.
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Description of Evidence
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This review was conducted by an analysis of the literature on mandibular
osteotomy and distraction.
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Review articles as well as original case reports were included.
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Description of Evidence
Summary of Surgeons and Their Contributions to Mandibular
Osteotomies Discussed in This Article
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Controversies and Consensus
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Mandibular distraction involves using inductive bone generation instead of
bone grafts.
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Distraction procedures have the advantage of being less invasive with
minimal dissection and blood loss and obviate the need for internal fixation.
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Drawbacks of the procedure include the need for a second operation to
remove the distractor as well as occlusal asymmetry from incorrect
distractor angle.
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Controversies and Consensus
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Craniofacial microsomia is the most common indication for unilateral
distraction.
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Pierre Robin sequence is the most common indication for bilateral
distraction.
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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.
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Bilateral distraction is most commonly used for Pierre Robin sequence as
well as cases of respiratory compromise or obstructive sleep apnea.
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Controversies and Consensus
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With regard to the specific osteotomy technique for distraction, the oblique
angle cut is the most commonly used approach.
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The oblique angle allows placement of the distractor in a horizontal or
oblique plane. Its main disadvantage is the obliteration of the gonial angle.
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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.
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The main disadvantage of the vertical cut is a higher risk of relapse in
patients with high-angle class II malocclusion.
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Comment
Recent Advances and Future Directions in Mandibular Distraction
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Indigenous transport distractors, which are preformed, intraoral boneanchored devices, avoid many of the complications of external devices,
such as infection and scars.
– Found to be effective in a dog model.
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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.
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Comment
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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.
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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.
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Hydraulics allow the physician to measure daily force and make
adjustments as necessary, but the current models were not accurate in
distraction.
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Conclusions
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The mandibular osteotomy has evolved significantly over the past 200 years
and has led to the development of mandibular distraction osteogenesis.
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Use of mandibular distraction osteogenesis requires excellent patient
compliance, still carries significant risk, and must be fine-tuned.
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Research is under way for the development of less bulky and automated
continuous distraction devices.
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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.
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Contact Information
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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 14th St, New York,
NY 10003 (saman@theidealface.com).
Conflict of Interest Disclosures
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None reported.
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