1. Early Mandibular Distraction Osteogenesis in 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

14. 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