Quantitative Results of Mandibular Distraction Osteogenesis in Pierre Robin

Infants Using a Vertical Ramus Osteotomy

and Internal Distraction Device

Grant A. Fairbanks, MDGeorge M. Varkarakis, MD

Andrea G. Scherer, BARobert J. Havlik, MD

Division of Plastic Surgery

Disclosures

No Conflicts of Interest

Background

• Pierre Robin – 1923– Sequence

• Hypoplastic Mandible (micrognathia)

• Glossoptosis• Airway Obstruction• +/- Cleft Palate

• Incidence – 1 in 5000 - 50,000 (Mathes Plastic Surgery Copyright © 2009 Elsevier Inc. p 511)

Background

• Ventilatory Obstructive Apnea – Newborn

• Challenging and Controversial Problem

• Options for Intervention– Observation / Positioning– Tongue / Lip Adhesion– Tracheotomy– Distraction Osteogenesis

Background

• Distraction Osteogenesis – Powerful Tool – Mandibular Hypoplasia

• Codivilla – 1905 (Femur)

• Ilizarov – 1952 (Long Bones)

• Snyder – 1973 (Canine Mandible)

• McCarthy – 1989 (Human Mandible)

Background• Evolution of

Techiques:– Osteotomies

• Angle• Ramus• Stairstep /

Inverted L

– Devices• External vs

Internal

Lengthening the Human Mandible by Gradual Distraction,McCarthy, JG, et al., PRS, 89:1, 1992

New Technique for Airway Correction in Neonates with Severe Pierre Robin Sequence, Denny, A, J Pediatrics,147:97, 2005

Craniofacial Microsomia…, Pediatric Plastic Surgery, Bentz, ML, QMP, 2008

Background

• Little Quantifiable Evidence

• Few Parameters to Guide Clinical Use

Purpose

• Experience at Indiana University

• Distraction osteogenesis (DO)

• Hypoplastic mandible (HM)

• Obstructive sleep apnea (OSA)

• Internal device

• Critical analysis

• Multi-channel polysomnography (PSG)

Methods

• A retrospective chart review

• All infant patients with HM and OSA

• Treated with vertical ramus osteotomy

• Mandibular DO

• 2004-2008

Methods

• Criteria – 1) Hypoplastic Mandible– 2) Obstructive Sleep Apnea

• preoperative sleep study (or inability to extubate)

– 3) Age Less than Six Months

Methods• Risdon incision

• Coronoid resection

• Vertical ramus osteotomies

Methods

• Internal titanium distraction devices

Methods

• Latency phase – 4 days

• Activation phase – Rate of 1 mm/day – 16-20 mm

• Consolidation phase– Minimum of 2

days/mm of distraction (36-40 days)

Results

• 36 patients

• Distraction length – Mean 18 mm – Range 16-20 mm

• Edge-on Occlusion or Slightly Overcorrected

Results• Complete Improvement - 34 (94%)

Results

• Associated complications– Tracheostomy – 2 (5.5%)

• 1 with a rigid chest from chondrodysplasia punctata

• 1 with severe periventricular leukomalacia

– Infection - 4 (11%) – Transient Facial Nerve Paresis - 1 (3%)

Results• All cases

– Mandibular dental midline remained true to the maxillary dental and facial midline

– Favorable Occlusal relationship – No compensatory mandibular

overgrowth

Results• Pre-operative and post-

operative PSG’s available for review (n=20)

• Apnea-Hypopnea index– #apneas + #hypopneas / hour – Pre-operative Mean 47.8 (20-

92)– Post-operative Mean 6.2 (0-

14)– Mean Improvement 87%

• Oxygen Desaturation– Pre-Op Mean 71% (59-84%)– Post-Op Mean 88% (72-94%)

Conclusion DO using a vertical ramus osteotomy

with an internal device:

• Preservation of the inferior alveolar nerve

• Minimizes the risk of injury to the facial nerve and dental elements

• Yields a favorable and nearly imperceptible aesthetic result

• Provides for effective correction of ventilatory obstruction in the infant with a hypoplastic mandible

Conclusion• Study documents:

– Quantifiable Pulmonary Criteria for the Clinical Results of Distraction Osteogenesis

– 87% improvement

• Recommendation: – Distraction

Osteogenesis in Infants

– Mandibular Hypoplasia

– Obstructive Sleep Apnea

– AHI of >20

Thank You