Endoscopic Monobloc Advancement With Ultrasonic Osteotomy

Monobloc Distraction and Facial Bipartition Distraction with External Devices

Monobloc and bipartition advancement by external distraction plays a major role in the treatment of syndromic craniosynostosis. They can reverse the associated facial deformity and play a role in the management of ocular exposure, intracranial hypertension, and upper airway obstruction. Facial bipartition distraction corrects the intrinsic facial deformities of Apert syndrome. Both procedures are associated with relatively high complication rates principally related to ascending infection and persistent cerebrospinal fluid leaks. Modern perioperative management has resulted in a significant decline in complications. External distractors allow fine tuning of distraction vectors and improve outcome but are less well tolerated than internal distractors.

Advances in the Treatment of Syndromic Midface Hypoplasia Using Monobloc and Facial Bipartition Distraction Osteogenesis

Midface hypoplasia or retrusion remains a persistent feature of syndromic craniosynostosis years after successful treatment of the cranium. Although expansion of the cranial vault in infancy by traditional fronto-orbital advancement, posterior expansion, or both, can treat the immediate intracranial constriction, midface hypoplasia and its stigmata of exorbitism, sleep apnea, central face concavity, and malocclusion remain suboptimally treated. Initial enthusiasm for the procedures was tempered due to a high rate of infectious complications; timing and indications for surgery continue to stir controversy. During the last decade renewed interest with the monobloc and facial bipartition procedure using distraction osteogenesis with either an internal or external distraction system has decreased morbidity significantly. These procedures have re-emerged as powerful and comprehensive tools in the treatment of syndromic midface hypoplasia.

Cranium and midface distraction osteogenesis: current practices, controversies, and future applications

BACKGROUND

The adaptation of distraction osteogenesis (DO) to the midface and cranium in the 1990s and the advancements that followed at the turn of the century resulted in a shift of paradigm in craniofacial surgery. Because skeletal advancement was not sudden anymore, but incremental, the monobloc advancement became safer to perform. Because bone was generated in the distraction gap, bone grafts were no longer needed, and younger patients could benefit from craniofacial advancement. Today, DO is the most powerful tool to simultaneously correct both exorbitism and the respiratory impairment of the faciocraniosynostosis, but practices vary greatly between teams.

METHODS

Current practices, controversies, and near-term future applications will be outlined and discussed.

RESULTS

Our current treatment strategy for faciocraniosynostosis is based on early intervention (<18 months of age) to prevent irreversible brain damage. In the first 6 months of life, infants with faciocraniosynostosis receive posterior vault decompression. We currently use posterior vault distraction, using 2 internal distractors. Around 18 months of age, a frontofacial monobloc advancement with DO is performed. It further decompresses the brain, improves respiratory function, and corrects exorbitism. Because we operate at such an early age, we favor internal over external distractors. In severe faciocraniosynostosis, when midface hypoplasia causes major exorbitism endangering the eye or causes respiratory distress requiring a tracheotomy, we do not hesitate to perform a frontofacial monobloc advancement with DO before the age of 18 months, reinforcing the frontozygomatic junction with a plate and placing a transzygomatic pin. The pin is then connected to a traction rope. We frequently use the external distractors, which allow precise control over the rotation of the maxilla and are well tolerated after 5 years of age. When midface hypoplasia is very severe, we combine external and internal distractors.

CONCLUSIONS

The ongoing debate between proponents of internal versus external distractors or 1-stage versus 2-stage approach is based mostly on anecdotal data. Multicenter prospective studies are necessary to bring objective data to answer these questions.