Cruzon and Apert Syndromes
Introduction
Corrective surgery in children with craniofacial syndromes is a complicated subspecialty of facial reconstructive surgery that requires the expert skill of several different specialists working together. Treatment should be performed by experienced craniofacial surgeons who are intimately involved with a craniofacial center. All of our surgeons are experienced in the treatment of children with Cruzon and Apert syndromes and are integrated with the New Jersey Institute for Craniofacial Surgery serving as the Craniofacial Surgeons, Plastic & Reconstructive Surgeons, and the Oral & Maxillofacial Surgeons for the Institute. Dr. Amato authored one of the definitive book chapters on the surgical reconstruction of Cruzon and Apert syndromes with Dr. Jeffrey Posnick.
Cruzon and Apert syndromes are two of the most common types of syndromic cranisynostosis. They are characterized by the premature fusion of certain bones of the face and skull. Because growth is restricted in the areas of premature fusion, overgrowth occurs in the areas that allow expansion for brain growth. This type of unbalanced growth leads to the characteristic facial appearances.
Mutations in the FGFR2 gene cause Cruzon and Apert syndromes. This gene produces a protein called fibroblast growth factor receptor 2 (FGFR2). Among its multiple functions, this protein signals immature cells to become bone cells during embryonic development. A mutation in a specific part of the FGFR2 gene alters this protein and causes prolonged signaling, which can promote the premature fusion of bones in the skull, hands, and feet.
In almost all instances of children born with Cruzon or Apert syndrome, their mother and father have normal genes, there is no history of the syndrome in either family, and the mother did nothing to cause the syndrome during the pregnancy. Cruzon and Apert syndromes are autosomal dominant conditions, meaning that only one parent needs to have an abnormal gene for the child to inherit the disease. Therefore, a person with Cruzon or Apert syndrome has a 50% chance for each pregnancy of passing this mutation on to a child. It is possible to ensure that an individual with Cruzon or Apert syndrome does not pass the syndrome to their child by using in-vitro fertilization and selecting an embryo for implantation that does not have the syndrome.
Cruzon Syndrome
Cruzon syndrome was first described by the French neurosurgeon, Dr. Louis Edouard Octave Crouzon, in 1912. The growth restrictions in Cruzon syndrome result in an abnormal shape of the skull (craniosynostosis), wide-set eyes (hypertelorism), shallow eye sockets with bulging eyes (ocular proptosis), eyes that do not point in the same direction (strabismus), growth restriction of the entire midface (midface hypoplasia), an underdeveloped upper jaw (maxillary hypoplasia), and significant dental issues.
Five percent of individuals with Crouzon syndrome have pigmentary changes in the skin fold regions referred to as acanthosis nigricans. These individuals are said to have Crouzon syndrome with acanthosis nigricans.
The chances of two unaffected parents having a child with Crouzon syndrome is estimated to be between 1 in 50,000 and 1 in 100,000 births.
Apert Syndrome
Apert syndrome was first described by the French neurologist Dr. Eugene Apert in 1906. The growth restrictions in Apert syndrome result in an abnormal shape of the skull (craniosynostosis), wide-set eyes (hypertelorism), shallow eye sockets with bulging eyes (ocular proptosis), eyes that do not point in the same direction (strabismus), an underdeveloped upper jaw (maxillary hypoplasia), and significant dental issues. The growth restriction of the entire midface (midface hypoplasia) is different from that seen in Cruzon syndrome. In Apert syndrome, the midface is not only retruded but also concave, resulting in a “sunken-in” appearance. This is an important distinction because the surgical procedure necessary to correct these issues may be different from that used in Cruzon syndrome (see Midface Advancement).
Although the facial characteristics of Apert and Cruzon syndromes are similar, Apert syndrome differs in several ways:
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The eyes tend to be farther apart (more significant hypertelorism)
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There is a space between the upper and lower front teeth when the mouth is fully closed (anterior open bite)
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The upper jaw is canted upward (counterclockwise rotation)
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The face and forehead are wider
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The midline of the face is “sunken in” (concave)
In addition to the facial features, individuals with Apert syndrome have webbed or fused fingers and toes. The severity of the fusion varies, but at least three digits on each hand and foot are typically fused together.
The chances of two unaffected parents having a child with Apert syndrome are estimated to be between 1 in 65,000 and 1 in 88,000 newborns.
References
Apert E. De l’acrocephalosyndactylie. Bull Soc Med. 1906;23:1310.
Crouzon, O. Dysostose cranio-faciale héréditaire. Mem Soc Med Hop (Paris). 1912;33:545.
Cohen MM. Birth prevalence studies of the Crouzon syndrome: comparison of direct and indirect methods. Clin Genet. 1992 Jan;41(1):12-5.
Cohen MM. Birth prevalence study of the Apert syndrome. Am J Med Genet. 1992 Mar 1;42(5):655-659.
GeneReviews®. Nathaniel H Robin, MD, Marni J Falk, MD, and Chad R Haldeman-Englert, MD. FGFR-Related Craniosynostosis Syndromes. [Internet]. Initial Posting: October 20, 1998; Last Update: June 7, 2011.
National Library of Medicine (U.S.). Genetics Home Reference. [Internet]. Bethesda, MD: The Library; 2013 Sep 16. Cystic fibrosis [reviewed 2012 Aug; cited 2013 Sep 19]. Available from: http://ghr.nlm.nih.gov/condition/cystic-fibrosis.
Posnick JC, Amato JP. Craniofacial dysostosis syndromes: evaluation and staging of reconstruction. In: Fonseca RJ, Marciani RD, eds. Oral and Maxillofacial Surgery, 2nd ed. St. Louis, MO: Saunders, 2009:880-921.
Cranio-Orbital Advancement
Cranial surgery in children with Cruzon and Apert syndromes is a complicated subspecialty of facial reconstructive surgery that requires the expert skill of several different specialists working together. Treatment should be performed by experienced craniofacial surgeons who are intimately involved with a craniofacial center. All of our craniofacial surgeons are integrated with and serve as the Craniofacial Surgeons, Plastic & Reconstructive Surgeons, and the Oral & Maxillofacial Surgeons for the New Jersey Institute for Craniofacial Surgery. Dr Amato authored one of the definitive book chapters on the surgical reconstruction of Cruzon and Apert syndromes with Dr. Jeffrey Posnick.
Figure 1: Model of Cranial-Orbital Advancement Surgery
Crouzon and Apert syndromes are genetic conditions in which the sutures of the skull fuse prematurely, not allowing for normal growth of the brain and skull. This commonly leads to a buildup of the fluid that surrounds the brain, referred to as hydrocepahlis. In turn, hydrocephalis can lead to increased intra-cranial pressure requiring drainage of the fluid and the placement of a shunt to protect the health of the brain. These patients are also at a high risk for developing Chiari malformation, which affects the back part of the brain (cerebellum), important for balance and coordination.
Children with Crouzon and Apert syndromes typically require reconstruction of the skull to achieve a normal head shape and to treat or prevent increased pressure around the brain. Typically between 4 and 12 months of life, a cranio-orbital advancement is performed by a craniofacial surgeon and a pediatric neurosurgeon. During this procedure, the bone of the forehead and the upper portion of the eye sockets are reshaped and advanced forward. The goals of the surgery are:
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To release the prematurely fused sutures of the front part of the skull
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To create further room for the brain to expand
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To reshape and advance the forehead forward
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To reshape and advance the superior portion of the eye sockets
After the procedure, children remain in the hospital for approximately 3 to 5 days. Overall the procedure is well tolerated by the children.
References
Posnick JC, Amato JP. Craniofacial dysostosis syndromes: evaluation and staging of reconstruction. In: Fonseca RJ, Marciani RD, eds. Oral and Maxillofacial Surgery. 2nd ed. St. Louis, MO: Saunders, 2009:880-921.
Midface Advancement
Lefort III, Monobloc, and Facial Bipartition
Midface surgery in children with craniofacial syndromes is a complicated subspecialty of facial reconstructive surgery that requires the expert skill of several different specialists working together. Treatment should be performed by experienced craniofacial surgeons who are intimately involved with a craniofacial center. All of our craniofacial surgeons are integrated with the New Jersey Institute for Craniofacial Surgery and function as the Craniofacial Surgeons, Plastic & Reconstructive Surgeons, and Oral & Maxillofacial Surgeons for the Institute. Dr. Amato authored one of the definitive book chapters on the surgical reconstruction of Cruzon and Apert syndromes with Dr. Jeffrey Posnick.
Figure 1: Lefort III
Figure 2: Monobloc Advancement
Figure 3: Monobloc Advancement with Facial Bipartition
Surgical advancement of the midface may be required to improve breathing and to help normalize a child’s appearance. Advancement of the midface will move the lower half of the orbits (eye bones), nose, cheeks, and upper jaw forward. For this reason, the midface advancement has the greatest impact in normalizing a child’s appearance.
If surgical correction to advance the midface is necessary, it is typically performed between 6 and 9 years of age. Performing a midface advancement procedure prior to 5 years of age is not recommended for multiple reasons. Midface advancement procedures can be performed at ages older than 9 years old if waiting is preferred.
At 6 to 9 years of age:
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A majority of the growth of midface is completed.
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The cranial vault and orbits attain approximately 85 to 90% of their adult size at this age, allowing for a final reconstruction of those structures at the time of midface advancement if necessary. If a final reconstruction of the cranial and orbital structures are performed in conjunction with a midface advancement, the procedure is referred to as a monobloc advancement.
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Psychosocial considerations support this age range.
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The permanent molar teeth have erupted into the mouth.
When the procedure is carried out at this age, the child may progress through school with an improved body image and self-esteem. Corrective jaw surgery will be necessary at the time of skeletal maturity to achieve an ideal occlusion and facial balance.
Conventional Surgery vs. Distraction Osteogenesis
Midface advancement can be performed in a conventional manner in which the bones of the midface are advanced and held in their new position using titanium plates and screws at the time of surgery. An alternative procedure referred to as distraction osteogenesis may be recommended for advancement of the midface. When distraction of the midface is performed, the bones of the midface are separated, as they would be in a conventional procedure; however, they are not moved forward at the time of the procedure. Instead of being moved forward, a special device is attached to the face that will allow the midface to be moved forward gradually over the course of 1 to 2 weeks after the surgery. Gradually advancing the midface over time produces a more stable result because the soft tissues are allowed to stretch to accommodate the movement and bone will be allowed to form between the separated bone segments as they are slowly advanced.
Figure 4: Distraction of Lefort III
The decision of whether to use distraction or conventional surgery will depend on several factors:
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The age of the child
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The magnitude of the necessary movement
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The type of procedure (Lefort III, monobloc, monobloc with facial bipartition)
For more information concerning distraction osteogenesis, please visit our distraction portal at ……
References
Posnick JC, Amato JP. Craniofacial dysostosis syndromes: evaluation and staging of reconstruction. In: Fonseca RJ, Marciani RD, eds. Oral and Maxillofacial Surgery, 2nd ed. St. Louis, MO: Saunders, 2009:880-921.
Monobloc Facial Bipartition
This text is currently under development. Please check back later for information about Monobloc Facial Bipartition.
Corrective Jaw Surgery
Corrective jaw surgery in patients with Cruzon or Apert syndrome requires a complex knowledge craniofacial surgery to understand the previous procedures that were performed as well as the best plan for future procedures. This surgery requires a skilled craniofacial jaw surgeon, as the planning and technical executions are complex. All members of our team are experienced craniofacial jaw surgeons and comprise the entire jaw surgery section of The New Jersey Institute for Craniofacial Surgery. Dr. Amato authored one of the definitive book chapters on the surgical reconstruction of Cruzon and Apert syndromes with Dr. Jeffrey Posnick.
Typically children with Cruzon or Apert syndrome will undergo some type of midface advancement procedure between 6 and 9 years of age, either a Lefort III procedure, monobloc advancement, or monobloc with facial bipartition. These types of procedures are performed to advance the entire midface—the eye bones, cheeks, nose, and upper jaw—forward. Unfortunately, positioning the eye bones, nose, and cheeks into their ideal position typically results in a nonideal position for the upper jaw. Therefore, corrective jaw surgery is usually necessary when skeletal maturity is achieved (around 16 years old) in order to reposition the upper and lower jaws into a more ideal position.
When skeletal maturity is reached, the upper jaw is usually angled upward and needs to be rotated down in the anterior (front), creating a gap between the bone requiring a bone graft. Our approach to this procedure involves performing a facial scan from which an exact 3D model of the skull of the patient is produced. The surgery is then performed on this model to determine the exact movements of the jaws and the size of the gap created. Usually the gap is large enough that a procedure referred to as distraction osteogenesis is preferred to avoid the need for a bone graft and to provide a more stable final result.
When it is determined that distraction of the midface is preferred, we utilize a custom-designed distraction device or multiple devices to achieve the best possible results. To learn more about our custom facial distraction devices, please visit our facial distraction portal at www.theamatocenter.com
References
Posnick JC, Amato JP. Craniofacial dysostosis syndromes: evaluation and staging of reconstruction. In: Fonseca RJ, Marciani RD, eds. Oral and Maxillofacial Surgery. 2nd ed. St. Louis, MO: Saunders, 2009:880-921.