Pierre Robin Sequence: Introduction

Pierre Robin Sequence (PRS), also known as Pierre Robin Syndrome or Pierre Robin Malformation, is a congenital condition characterized by a triad of micrognathia (small lower jaw), glossoptosis (posteriorly placed tongue), and airway obstruction. It is often associated with cleft palate, although this is not always present.

Key points:

• Prevalence: Estimated at 1 in 8,500 to 14,000 births
• Etiology: Can be isolated or part of a broader syndrome
• Pathogenesis: Believed to result from a sequence of events initiated by mandibular hypoplasia during early fetal development
• Significant morbidity related to upper airway obstruction and feeding difficulties
• Management requires a multidisciplinary approach

Clinical Features of Pierre Robin Sequence

Primary Features:

• Micrognathia (small lower jaw)
  • Often apparent on prenatal ultrasound
  • Results in a receding chin appearance
• Glossoptosis (posteriorly displaced tongue)
  • Can obstruct the airway, especially when the infant is supine
  • May cause feeding difficulties
• Upper airway obstruction
  • Ranges from mild to severe
  • Can lead to respiratory distress, especially during sleep
• Cleft palate (in about 90% of cases)
  • Usually U-shaped and wide
  • Can be complete or incomplete

Associated Features:

• Feeding difficulties
  • Due to airway obstruction and/or cleft palate
  • Can lead to failure to thrive
• Ear infections and hearing loss
  • Related to dysfunction of the Eustachian tubes
• Sleep-disordered breathing
  • Obstructive sleep apnea is common
• Dental anomalies
  • Crowding, malocclusion
• Speech and language delays

Syndromic Associations:

PRS can occur as part of various genetic syndromes, including:

• Stickler syndrome
• Velocardiofacial syndrome (22q11.2 deletion)
• Treacher Collins syndrome
• Nager syndrome
• Marshall syndrome

Diagnosis of Pierre Robin Sequence

Clinical Diagnosis:

Diagnosis is primarily based on clinical presentation:

• Presence of the characteristic triad: micrognathia, glossoptosis, and airway obstruction
• Physical examination focusing on craniofacial features
• Assessment of respiratory status and feeding abilities

Prenatal Diagnosis:

• May be suspected on prenatal ultrasound showing micrognathia and polyhydramnios
• 3D ultrasound or MRI can provide more detailed imaging

Postnatal Evaluations:

• Comprehensive physical examination
• Airway assessment
  • Flexible nasopharyngolaryngoscopy
  • Sleep study (polysomnography)
• Feeding evaluation
  • Videofluoroscopic swallow study
• Hearing assessment
• Genetic testing (to identify associated syndromes)

Differential Diagnosis:

• Isolated cleft palate
• Treacher Collins syndrome
• Nager syndrome
• Stickler syndrome
• Velocardiofacial syndrome
• Isolated micrognathia

Additional Investigations:

• Craniofacial CT or MRI (for detailed anatomical assessment)
• Echocardiogram (to rule out associated cardiac anomalies)
• Ophthalmological examination
• Developmental assessment

Management of Pierre Robin Sequence

Management of Pierre Robin Sequence requires a multidisciplinary approach and is tailored to the severity of the condition:

Airway Management:

• Positioning
  • Prone or side-lying position to reduce airway obstruction
  • May require special beds or positioning devices
• Non-invasive respiratory support
  • Nasopharyngeal airway
  • Continuous positive airway pressure (CPAP)
• Surgical interventions (for severe cases)
  • Tongue-lip adhesion
  • Mandibular distraction osteogenesis
  • Tracheostomy (rarely needed)

Feeding Management:

• Specialized feeding techniques
  • Use of specially designed bottles and nipples
  • Positioning during feeding
• Nasogastric tube feeding (if necessary)
• Gastrostomy tube placement (for severe cases)
• Nutritional support and monitoring

Cleft Palate Repair:

• Usually performed between 9-18 months of age
• May be delayed if significant airway issues persist

Orthodontic and Dental Care:

• Early orthodontic intervention may be necessary
• Regular dental check-ups and hygiene
• Management of malocclusion

Speech and Language Therapy:

• Early intervention for speech and language development
• Management of velopharyngeal insufficiency

Hearing Management:

• Regular hearing assessments
• Management of otitis media and hearing loss
• Consideration of tympanostomy tubes

Genetic Counseling:

• For families, especially if PRS is part of a genetic syndrome

Developmental Support:

• Early intervention services
• Regular developmental assessments

Long-term Follow-up:

• Regular evaluations by craniofacial team
• Monitoring of growth and development
• Ongoing assessment of airway and feeding status
• Psychological support for patients and families

Emerging Therapies:

• Prenatal interventions (experimental)
• Tissue engineering approaches for mandibular growth