Craniosynostosis is a congenital deformity of the skull that occurs when one or more of the cranial sutures close early. The skull is normally made up of bones separated by fibrous joints called sutures. Open sutures allow the brain to expand and grow rapidly in the first few years of life. The metopic suture (midline, forehead) often closes within the first couple of years, but others remain open into early adulthood. If one or more of the sutures close early, cranial volume is restricted (not adequate) and can compress the brain. The skull then expands in areas adjacent to the fused suture. The most common forms of craniosynostosis involve the fusion of a single suture resulting in a fairly consistent change in skull shape. Multiple sutures can fuse resulting in less predictable head shapes and much more severe and urgent forms of brain compression. The incidence of all forms of single suture craniosynostosis is 1 in every 2000 live births.
Types of Deformities
Sagittal synostosis (scaphocephaly) is the most common single suture closure in infants. It affects about 1 in every 5000 live births and occurs more often in males. Closure of the sagittal suture prevents the skull from expanding in width with a compensatory increase in length resulting in a head shape that is long and narrow. The baby may have a protruding (bossed) forehead and narrow temples.
Metopic synostosis (trigonocephaly) is fusion of the suture that extends from the top of the head down the forehead. The result is a triangular head shape with a pointed forehead, midline ridge, and eyes that may appear close together ( hypotelorism). The degree of deformity can vary from a mild ridge to a more severe noticeably pointed forehead.
Unilateral coronal synostosis (anterior plagiocephaly ) occurs when one side of the coronal suture is closed. This results in a flattened appearance of the forehead and eyebrow on the affected side. Bicoronal synostosis (brachycephaly) occurs when both sides of the coronal suture close early and results in a flat, recessed forehead.
Lambdoid synostosis (posterior plagiocephaly ) is the rarest form of craniosynostosis. It causes flattening of the back of the head on one side, protruding mastoid bone, and posterior positioning of the ear on the affected side. It can be distinguished from abnormal molding of the head (“positional plagiocephaly”) by a craniofacial surgeon or pediatric neurosurgeon often without needing to obtain a CT scan.
Diagnosis
Craniosynostosis is usually suspected due to the abnormal head shape and should be referred to the craniofacial team for evaluation. To confirm the diagnosis, our center obtains a craniofacial ct scan with 3D reformatting.
Treatment
The goal of surgical treatment is to expand the skull volume to relieve the pressure on the brain. Equally important is an accurate reconstruction of the form of the skull. In some cases a slight overcorrection is necessary to compensate for future slow growth in the affected region. Surgery is performed by the craniofacial (plastic) surgeon and the pediatric neurosurgeon working together to release the fused suture and reshape the affected bones. The timing of surgery depends on the infant and type of craniosynostosis (which suture is involved) but is generally performed before a year of age. The rationale for the timing of surgery is based on complex factors including bone quality of the skull, the unique ability of infants to spontaneously close gaps left behind from the expansion, and brain growth patterns. We carefully monitor the infant’s head growth and developmental status while planning the surgery.
Once a surgery date is scheduled, parents are given information about preparing for surgery and hospitalization. A blood transfusion may be necessary during surgery. If parents feel strongly about donating blood, there is a Directed Donor program available through the Blood Donation Center. A pre-operative visit is scheduled for the week before surgery.
Surgery
The surgeon makes an incision from ear to ear that is “zig zagged” to allow the hair to grow back more naturally and cover the scar. This incision is necessary for the surgeons to adequately expose the area of surgery and have adequate access to the brain so that they can appropriately protect it during the surgery. The skull is removed and reshaped into the proper form. Tiny resorbable plates and screws are used to hold the shape. The procedure usually lasts between 4 – 8 hours. Children spend the first night in the pediatric ICU for careful monitoring, and remain in the hospital 3-5 additional days. There will be facial and eye swelling, IV lines and monitors while in the hospital. Pain medication is given through the IV the first day, then changed to oral medicine as the child begins to eat and drink. A routine post operative CT scan is done. When the child goes home, parents are given instructions about washing the hair, incision care and activity guidelines. There is a follow up visit approximately 2 weeks after discharge and then at 2, 6 and 12 month intervals.