Early Mandibular Distraction Osteogenesis in Pierre Robin Sequence

1. Early Mandibular Distraction Osteogenesisin Pierre Robin Sequence

2. Pierre Robin Sequence • Pierre Robin case report 1926 • one in 9000 births • micrognathi, glossoptosis, cleft palate. • Theories: • fetal head positioning, frequently associated with oligohydramnios. • a delay in neurological maturation • rhombencephalic dysneurulation • rare familial cases reported - localized intrinsic failure of mandibular growth may be a factor in some cases. • Catchup mandibular growth in most, but mandibular dimensions will remain below age-matched norms.

3. Early Considerations • varying degrees of airway obstruction and feeding difficulties. • mechanism - falling back of the tongue into the oral pharynx. • Immediate supportive measures required in over 70 percent of affected infants. • Caouette-Laberge ( 1994) clinical classification of respiratory symptoms: • group I, adequate respiration in prone position and bottle feeding; • group II, adequate respiration in prone position but feeding difficulties requiring NGT; • group III, children with respiratory distress requiring respiratory support and NGT.

4. Early Management • Supportive measures • Lying prone • Tongue-lip adhesion • Kirschner (2003) - >40% Group III infants required tracheostomy after tongue-lip adhesion • Denny (2004) - additional 1.9 secondary procedures • Nasopharyngeal airway • Tracheostomy (12-42%) • K wire fixation, genioglossus stripping

5. Problems with tracheostomy • Increased morbidity • Donnelly, Int J Pediatr Otorhinolaryngol. 1996 • n=29; 41% complication rate (<1yo- 64%) • 25 months average decannulation • Midwinter, J Laryngol Otol. 2002 • n-=143; 46% complication rate • 25 months mean decannulation • Mortality 2.7% • Carr, Laryngoscope. 2001 • N=142; 43% serious complications • Mortality 0.7%

6. Problems with tracheostomy • Poorer Speech Outcomes • Jiang, Int J Pediatr Otorhinolaryngol. 2003 • Affects speech and language development in those with and without neurological disorders. • Risk factors: age at tracheostomy, and duration. • Better outcome with early decannulation • Simon, Int J Pediatr Otorhinolaryngol. 1983 • All children decannulated during the linguistic stage exhibited specific spoken language delays • phonological impairment proportional to duration

7. Problems with tracheostomy • Prolonged • Tomaski, Laryngoscope 1995 • Average 3 years decannulation in PRS • Carer Impact • Financial Burden • Developmental Problems • Singer, Dev Med Child Neurol. 1989 • n=130 • Slower growth rate • Higher risk of behavioural problems • Most will require special educational intervention

8. Mandibular Distraction: Background • External traction with halo (Callister 1937)

9. Mandibular Distraction: Background • External traction with pulley/ weight (Longmire, Sandford 1940)

10. Mandibular Distraction: Background • Mandibular DOG • McCarthy 1992, Molina/Ortiz-Monasterio 1995 • Use in children with airways obstruction • Moore, David 1994 • Cohen 1999 • Use in Pierre Robin • Denny 2001,2002 • Monasterio 2002 • Burstein 2005 (internal resorbable device)

11. Mandibular Distraction: Background • External distractor (Denny 2002) • linear Howmedica distraction device

12. Mandibular Distraction: Background

13. Mandibular Distraction: Background

14. Mandibular Distraction: Background • Internal resorbable device

15. Early Distraction: Controversies • Conservative management alone • 20-40% will not respond to positioning or glossopexy • Rapid distraction • 2mm/day vs 1mm/day • In goats – demyelination noted at 2mm/day (Hu, J Oral Maxillo Surg 2001) • Effect on dentition • Screw holes • Infraalveolar nerve • Effect on subsequent mandibular growth • Facial scarring

16. Indications for early distraction in Pierre Robin • Failure of conservative measures to improve respiration and feeding • Documented tongue base obstruction • Center with expertise In distraction