Robin Sequence: More Than a Receding Chin

By John Mulliken, MD, Director, Craniofacial Centre, Boston Children’s Hospital

Children born with Robin sequence (named for an early 20th century French physician; pronounced row-BAN) have a lower jaw that is smaller than normal (micrognathia) or set back from the upper jaw (retrognathia). This underdevelopment of the jaw causes the tongue to fall back- ward in the throat, resulting in feeding and breathing difficulties.

Formerly known as Pierre Robin syndrome, Robin sequence (RS) usually includes a cleft palate, an opening in the roof of the mouth that is wide and more U-shaped than that in more typical cleft palate. The cleft is thought to be caused by the tongue being pushed upward by the lower jaw, blocking fusion of the palatal shelves during the first trimester of fetal development.

Many RS infants also have tonguetie (ankyloglossia) in which the tip of the tongue is tethered to the floor of the mouth, making speaking and eating difficult.

Diagnostic imaging can help doctors predict RS before birth. Prenatal ultrasonography can detect a small jaw, and MRI can show a cleft palate.

RS is sometimes part of a syndrome—a group of associated anomalies—that may be inherited. The most common genetic causes for syndromic RS are Stickler syndrome (a disorder of the body’s collagen) and velocardiofacial syndrome (a condition involving heart defects), but there are more than 30 other possible diagnoses.

RS may be minor (Grade I), moderate (Grade II), or severe (Grade III). A baby with Grade I RS can eat and breathe well while lying on the back. A baby with Grade II breathes well but chokes when fed. A Grade III baby cannot eat or breathe without obstruction, resulting in low levels of oxygen in the blood.

A range of treatments

Some hospitals rely on conservative measures, such as a feeding tube through the nose into the stomach, breathing tube in the nose, and prone positioning. Long-term use of a feeding tube, however, often Infant with Robin sequence and leads to refusal to accept food by intraoral view mouth. It may take months before of U-shaped the infant will eat normally.

Rarely, a tracheostomy, an operation in which a hole is made in the windpipe, is necessary to ensure the infant has enough oxygen. While effective, the procedure requires “around-the-clock” care.

For Grade III RS, the most aggressive approach is to cut the lower jaw on both sides and pull it forward using an appliance attached to the bone (distraction osteogenesis). At Boston Children’s Hospital, we only consider distraction for syndromic RS infants whose lower jaw will not grow normally, for example, Treacher Collins syndrome, Nager syndrome, and bilateral hemifacial microsomia.

Our first choice for infants with Grade III and some Grade II RS is a tongue-lip adhesion, a procedure that temporarily attaches the tip of the tongue to the inside of the lower lip to keep the tongue from blocking the airway. We use a grading system called GILLS that accurately predicts whether or not a tongue-lip adhesion operation is likely to be effective — which it usually is.

These infants use a feeding tube immediately after the operation and begin oral feeding by 10 days. They are discharged from hospital and monitored at home with a pulse oximeter — an oxygen- Robin measuring device — for and several weeks.

Cleft palate infants with RS should be closed before age 1. The tongue and lip are detached at the time of the palate repair.

Remarkably, the lower jaw grows to almost a normal size during the first few years of life in children with non-syndromic RS. Speech outcomes in these children are similar to those in children with common cleft palate. In contrast, patients with syndromic RS are two times less likely to develop normal speech. Furthermore, children with syndromic RS usually require surgical advancement of the lower jaw.