What is Apert syndrome?
Apert syndrome is a combined craniofacial deformity with characteristic hand and foot malformations. It is one of a group of craniosynostosis syndromes (prematurely fused skull bones) termed “acrocephalosyndactyly.” A known genetic link exists, and it can be passed on from generation to generation. The syndrome was named for a French pediatrician named Eugene Apert, who first described the condition in 1906. a spectrum of undergrowth conditions or malformations related to the craniofacial skeleton. The cranial deformity results from premature fusion of the coronal sutures of the skull, producing a shorter distance between the forehead and back of the head. This is called brachycephaly or bicoronal plagiocephaly. The midface is underdeveloped (ie, midface hypoplasia), and there is complete fusion of all fingers and toes. Apert syndrome occurs in approximately 1 in 160,000 newborns.
Why does Apert syndrome occur?
Apert syndrome is strongly linked to a gene mutation that is responsible for a specific hormonal receptor called FGFR2 (or, fibroblast growth factor receptor type 2). This, in turn, transmits a signal to prematurely close various growth plates in the body, including the skull, vertebrae, fingers, and toes. When the gene mutation occurs, it can be passed on to the next generation, however, most cases are still without a known cause. There is some thought that there may be additional genetic and environmental causes that may combine to produce the mutation.
What are the associated problems with Apert syndrome?
As mentioned above, children with Apert syndrome have a characteristic craniofacial appearance that is short but tall. The midface is underdeveloped, and eyes can bulge. Cleft palate occurs in approximately 75 percent of affected children. In some cases (approximately 45 percent), the fusion of skull bones creates an impediment to brain growth and results in elevated intracranial pressures. Speech and developmental delay are present to a variable degree. Nearly 70 percent of children with Apert syndrome will have some element of vertebral fusion, most commonly along the neck (or, cervical spine).
Hand deformities are universally present. They can be described as having varying degrees of fusion or webbing along all digits. The fused digits are short and typically have joined bones, skin, soft tissues, and nails. This is called complex and complete syndactyly. Movement of fingers is limited, and joints are stiff. Nonetheless, surgical correction can result in significant functional gains.
Fused toes also have varying degrees of joined nails and bones. Ingrown nails are common and require excision. There is a widened foot base, and occasionally, a firm bony mass (or, bony boss) can develop along the central portion of the forefoot.
Can Apert syndrome be inherited?
Yes, Apert syndrome is inherited to varying degrees in an “autosomal dominant” fashion. In other words, each successive generation can exhibit the syndrome, regardless of an unaffected partner. As mentioned previously, the condition can arise spontaneously with a mutation of the FGFR2 gene.
How is Apert syndrome treated?
Craniosynostosis is treated surgically between 9 and 12 months of age by way of a “fronto-orbital advancement.” The front part of the skull is separated and moved forward to allow room for the developing brain. Some centers are performing “posterior vault expansion” at 6 months of age, using a distraction method to grow bone via an external (or partially internal) geared device that is turned daily. This allows for a greater front-to-back distance of the skull to be achieved. Additional surgery may be required at 3 to 4 years of age to close any residual openings in the skull bones. Craniosynostosis surgeons perform these procedures.
Cleft palate, if present, is closed between 10-12 months of age. Please refer to the Cleft Lip and Palate section for details.
Correction of the underdeveloped midface usually occurs in early adolescence in order to allow for maximal growth to occur. However, in some children, this is done much sooner to relieve obstructive sleep apnea. Depending on the position of the forehead, various surgical options are possible. When fully grown, the child will then undergo jaw surgery to normalize the relationship between the upper and lower jaws when biting. A specialized jaw surgeon performs this type of surgery.
Hand deformities are addressed as early as 6 months of age and staged 3 months apart. A series of surgeries are required to sequentially separate the fingers safely. In the first surgery, the thumb and small finger are separated to allow for maximal improvement of hand function early on. Skin grafts are taken from the groins to re-line the new webs. The second surgery can be performed at approximately 9 months of age, but must be timed in order to avoid disrupting scheduled cranial surgery or cleft palate repair. In this second stage, an additional web is released on each hand followed by additional skin grafting from the groins. The third surgery then focuses on separating the remaining web and deepening the first web, once again using skin grafts from each groin. Both hands are addressed with each of these surgeries, followed by a 2-weeks period of casting of both arms to ensure optimal healing. Also, each of these surgeries can be combined with treatment of any ingrown nail problems. Rarely, the degree of fusion of the finger bones may be too severe to allow for safe separation of one digit. Under these circumstances, amputation of a finger may be required. Thankfully, this is not a frequent occurrence.
After the initial finger separations, correction of thumb deviation and deepening of webspaces are performed at approximately 5 years of age. Once again, nail plates can be narrowed. Unsightly skin grafted areas can be excised simultaneously, and casting is required for 3 weeks. Usually one hand is treated at a time to avoid disrupting the activities of an older child. Additional procedures may be required periodically for the next several years to correct finger curvature problems, nail plate issues, and deepening of webspaces. New techniques are being used to also lengthen short fingers and contour them to a more ideal form.
Fusion of toes can be corrected in a similar fashion as separation of hand syndactylies. Usually, hand and foot procedures are not combined in order to avoid unnecessary prolongation of surgery and to avoid simultaneously immobilizing the upper and lower extremities. However, webs are separated sequentially as in the hand to avoid compromising the circulation of any one digit. Ingrown nail issues are addressed at every opportunity. As the child grows, a prominence over the central forefoot may occur. In some cases, this bump may interfere with activities and cause pain. The bump may be shaved to re-distribute the weight over the forefoot (or, balls of the feet) more evenly.
What is the recovery from the surgeries for Apert syndrome?
Recovery from surgery for each component of Apert syndrome is highly variable. Usually, craniofacial procedures require hospitalization for several days, including a brief stay in a pediatric intensive care unit (PICU). Cleft palate repair requires an overnight stay. Swelling is significant following major cranial vault remodeling and tends to subside over the course of one week.
Hand surgery for Apert syndrome is significantly different. Although operating on several webs on both hands can take upwards of 8 hours to complete, most hand procedures can be done on an outpatient basis. Casting of the arms is required after every surgery for 2 to 3 weeks, depending on the degree of bony correction. However, children are allowed to engage in their regular activities right away. After the casts are removed, hand splints are fashioned by an occupational therapist to maintain the webspaces. They are worn every night for 3 months. During the day, the splint is taken off so that the child can use his or her hands.
Toe separation can be performed at any age, but is usually left towards the end in order to avoid interference with the more important hand and craniofacial surgeries. Similar to the hand procedures, the feet require a period of casting for 2 weeks following each surgery to ensure optimal healing of skin grafts and incisions.
Jaw or oral procedures will usually have dietary restrictions (soft diet only) for 6 weeks following surgery. All procedures require some level of scar management. The plastic surgeon should guide patients at every step.
What are the risks and complications of surgeries for Apert syndrome?
All procedures for correcting individual deformities related to Apert syndrome carry a different set of risks and potential complications. Extensive craniofacial procedures tend to carry a higher risk profile, but are still practiced safely in designated craniofacial centers. Airway complications are the most serious issue encountered. Anesthesia pre-evaluation is necessary to stratify risk and to make provisions at the time of surgery for successful intubation and postoperative management. In general, many of the risks encountered during surgery for Apert syndrome are directly proportional to the severity of the condition.
Stiffness of finger joints is common in Apert syndrome, with or without surgery. However, although fine finger movement is difficult to achieve, children with corrected Apert hand deformities lead very active lives with minimal limitations. When releasing webs, a chance of partial recurrence of the web is possible. This is called “webspace creep.” This sometimes requires deepening of spaces with another round of surgery or in combination with another procedure. Rarely, vascular compromise may lead to loss of a finger or toe. In addition, a rare complication of casting or compressive dressings is an elevation of pressures within compartments of the extremities, resulting in loss of circulation, nerve damage, and extreme pain. This requires emergent release of tight dressings and casts to avoid complications.
Bleeding, infection, and anesthetic complications are risks of any surgery. In addition, poor scarring or wound problems can occur rarely. Alopecia, or hair loss, may occur along the incision line within the scalp. More frequently, although improvement in function and appearance are possible, achieving perfect symmetry is elusive. Overcorrection or undercorrection may occur. Many times, revisional surgery will be required to improve scars, contour, or symmetry.