Pierre Robin Sequence
What Is Pierre Robin Sequence?
Pierre Robin sequence (PRS) is a birth defect that involves an abnormally small lower jaw and a tendency for the tongue to fall backward toward the throat and block the airway. PRS is called a sequence because it is thought to result from a series of events that take pla ce as the embryo forms in early pregnancy. In PRS, it is thought that the initial defect of the fetus's lower jaw leads to abnormal placement of the tongue. The displaced tongue causes clefting of the palate.
Pierre Robin Sequence in Children
In 1923, Pierre Robin, a French physician, linked the above symptoms with breathing problems in affected infants. The current complete name is Pierre Robin malformation sequence, but it is also known as Robin Anomalad; Pierre Robin complex; and Pierre Robin syndrome. PRS can occur by itself (isolated PRS) or in combination with other birth defects that affect the head and neck, such as Stickler syndrome.
Symptoms of Pierre Robin Sequence
Babies born with Pierre Robin sequence (PRS) may have cleft palate (roof of the mouth), micrognathia (small jaw) and glossoptosis (obstructing the airway). The cleft palate is typically rounded, sometimes called U-shaped, in comparison with the more common V-shaped cleft seen in other conditions. The baby also has a much smaller jaw marked by a receding chin. The tongue can appear large due to the small jaw and is often held far back in the throat.
Pierre Robin Sequence Diagnosis
To diagnose this condition, your doctor will examine your child carefully. An exam may be all that’s needed for diagnosis. When a baby is born with PRS, it is important to be sure they have no other abnormal conditions. In the first several months of life, the jaw often grows enough to improve breathing symptoms, but some children need surgery. So your doctor may do tests to check for other conditions.
Breathing and Feeding Problems
In the first months of life, the infant must be able to breathe and eat to survive and thrive. The first priority is keeping the upper airway open so the infant can breathe easily. Since the tongue often blocks the upper airway when the infant is placed on their back, placing the infant on their stomach is often necessary. Most times keeping the infant on their stomach is enough to prevent airway obstruction. If placing the infant on their stomach does not solve the problem, other treatments aimed at keeping the upper airway open are used. These include a nasopharyngeal airway or nasal trumpet (a small tube placed through the nose into the upper airway). If these treatments do not work, the lower jaw may need to be enlarged through a technique called distraction osteogenesis. This technique slowly lengthens the jawbone using a small metal device.
Enlarging the jaw brings the tongue into the mouth, preventing the tongue from obstructing the upper airway. In addition, a tongue-lip adhesion procedure can be performed to assist with breathing, and has shown great results. If the upper airway obstruction is extremely severe, then a tracheostomy (placement of a breathing tube in the windpipe) may be the best treatment. Once the infant is breathing comfortably, feeding is usually much improved. If it does not improve, the infant needs to be fed with a tube from the nose to the stomach for the first few months of life. If normal feeding does not develop, then a gastrostomy tube (a tube through the abdominal wall into the stomach) may need to be placed.
Other difficulties may accompany feeding and breathing problems. Two common problems are reflux of stomach contents into the throat and aspiration of liquid into the windpipe. These conditions are treated with medicine and dietary changes.
Cleft Palate and Hearing Problems
When the child with PRS reaches 12 to 18 months of age, the cleft palate will need to be repaired. These children often need tympanostomy tubes (small plastic tubes inserted in the eardrums) to improve hearing. Almost all children with cleft palate are prone to fluid buildup behind the eardrum, which can mildly or moderately affect hearing. Ongoing monitoring by an otolaryngologist (ear, nose and throat specialist) and an audiologist (hearing specialist trained to test hearing in infants and children) is recommended.
Neonatal Mandible Distraction Osteogenesis
In certain cases, a baby born with PRS may benefit from early mandible (lower jaw) surgery to avoid a tracheostomy. Our multidisciplinary team assesses each baby with PRS who is having breathing problems that cannot be treated by positioning or a nasal breathing tube. If the team decides that moving the baby's jaw forward has a good chance of improving breathing, they will recommend early mandible distraction osteogenesis.
This surgery starts with an osteotomy (a break) on both sides of lower jaw, and a small metal distraction device is placed under the skin and across the osteotomy. Two days later the device is activated — a screw is turned frequently to slowly open the osteotomy gap and move the lower jaw forward. The jaw moves forward at just 1.8 mm a day. As the lower jaw moves forward, the tongue moves forward, and the baby's airway at the back of the throat opens up. Once the jaw has been moved forward enough (usually 15 to 20 mm), the screw is no longer turned, and the osteotomy is allowed to heal over a period of six to eight weeks. A small second surgery is then performed to remove the device.
It's best for a child with PRS to be treated by an orthodontist or pediatric dentist who works with a craniofacial team. Since the lower jaw is small, crowding of the teeth is a frequent problem. However, the primary teeth are often quite small and able to fit in. It is not unusual for the last primary molar in the lower jaw to be a little late to grow in due to the crowding. Be sure to keep the primary teeth in good condition and repair cavities as needed. The primary teeth help maintain spaces, which will prevent problems with crowding as the permanent teeth come in. As the child grows, the relationship between upper and lower teeth improves. This is partially related to the growth of the lower jaw but it is also dependent upon the reduced growth of the upper jaw seen in children with clefts. To determine how the child’s jaws are growing, the orthodontist will take X-rays of the sides of the face.
Typical Orthodontic Treatment Plan for a Child with PRS
Pierre Robin sequence is treated in several stages.
2 to 6 years
Monitor the crowding and obtain a lateral cephalogram (X-ray of the face) and a panoramic X-ray image. The cephalogram will be used for growth analysis of the face to plan future treatment. The panoramic X-ray is used to identify the presence of permanent teeth and their positions.
6 to 11 years
As permanent teeth grow in, crowding is the main concern. Extractions of primary teeth will often be needed to help make room for the permanent teeth. Often, one permanent tooth on each side of the upper jaw and lower jaw needs to be extracted to allow the remaining teeth to fit in reasonable alignment.
12 to 20 years
Orthodontic treatment is often needed during the teenage years. Sometimes the lower jaw is still too small in relation to the upper jaw and orthodontic treatment alone cannot address the problem. In those situations, jaw surgery will be considered. To improve the position of the chin, surgical changes can be helpful.