CC
A 7-month-old male infant is referred by his pediatrician for evaluation of a cranial dysmorphology.
HPI
The mother of this 7-month-old, otherwise healthy male (craniosynostosis has a male predilection) has been concerned about the abnormal shape of his head, which was noticed immediately after birth. (Craniosynostosis is the premature fusion of the cranial sutures during intrauterine life. The deformity is often noticeable early [ Fig. 93.1 ].) The pediatrician has been closely observing this skull deformity for changes and resolution. It was initially assumed to be deformational plagiocephaly (a skull deformity caused by vaginal delivery or early fetal descent into the pelvis) and later was thought to be secondary to a positional plagiocephaly, an acquired skull deformity caused by a repetitive head position during sleep. (Nonsynostotic posterior plagiocephaly has increased since the American Academy of Pediatrics issued a recommendation that infants be placed on their backs during sleep to reduce the risk of sudden infant death syndrome.) Despite conservative management, the child continued to exhibit the cranial deformity, which appeared to slightly worsen over time. He is otherwise in good health, and the mother denies any behavioral abnormalities. He is referred for craniofacial evaluation. (The rate of detectable cranial abnormalities secondary to craniosynostosis has been reported to be as high as 1 in 1700 to 1 in 1900 births.)
PMHX/PDHX/medications/allergies/SH/FH
Noncontributory. The patient is up to date with all childhood immunizations, and there is no previous surgical history. The patient had an otherwise uneventful vaginal delivery.
There is no significant family history. (Mendelian inheritance patterns are rare for nonsyndromic craniosynostosis and are usually associated with other abnormalities except for metopic suture craniosynostosis, which has a 5% positive family history.)
With the exception of metopic craniosynostosis (which has a 43% incidence of associated malformations with no clear syndromic diagnosis), patients with nonsyndromic craniosynostosis are typically healthy and do not show other malformations commonly present in syndromic craniosynostosis.
Examination
General. The patient is a well-developed and well-nourished pleasant child in no apparent distress.
Maxillofacial. Examination of the skull reveals a mild dysmorphology (the exact dysmorphology varies greatly and depends on which portion or portions of the sagittal suture are involved) in which the cranial vault is narrow in the bitemporal and biparietal dimensions and abnormally elongated in the anteroposterior (AP) dimension. (This is called scaphocephaly, meaning “long and narrow.”) Frontal and occipital bossing is apparent (described as a “keel-like” appearance).
There are no midfacial or mandibular hypoplasia or asymmetry and no orbital dystopia (a relative discrepancy in globe position in the vertical and/or horizontal planes) or exophthalmos (anterior position of the globe relative to the orbital rims).
The fundoscopic examination is normal, with no evidence of papilledema (edema of the optic disc, which is indicative of elevated intracranial pressure [ICP]).
Intraoral. The results of the examination are within normal limits (nonsyndromic craniosynostosis is not associated with an increased incidence of cleft lip and cleft palate).
Extremities. There are no deformities. (Nonsyndromic craniosynostosis does not have any associated abnormalities of the extremities.)
Imaging
Plain film complete skull series comprise a potential initial diagnostic radiographic workup. (The clinical diagnosis of craniosynostosis must be confirmed radiographically.) In the current patient, the radiographs showed the absence of the entire sagittal suture. (Sagittal suture synostosis can involve the entire suture, the anterior portion only, or the posterior portion only. If the sutures appear patent on a radiographic study of diagnostic quality, craniosynostosis can be ruled out.)
Craniofacial axial and coronal (or reformatted) cut computed tomography (CT) scans and three-dimensional reconstructions provide more detailed morphologic information, which is very useful during surgical planning. (CT scans are also indicated when plain films are nondiagnostic.) In the current patient, CT scans showed a scaphocephalic skull deformity, which is consistent with synostosis of the sagittal suture. CT scans of the head showed no masses (the possibility of an intracranial mass should be included in the differential diagnosis of cranial vault abnormalities) and no hydrocephalus. (This is usually not encountered in single-suture craniosynostosis but may occur independently; hydrocephalus is seen in approximately 10% of cases in which multiple sutures are involved.)
Labs
In an otherwise healthy, 7-month-old patient, the preoperative laboratory evaluation should include hemoglobin and hematocrit levels as well as coagulation studies.
Assessment
Nonsyndromic craniosynostosis involving the entire sagittal suture.
Treatment
There are two primary types of surgical management for nonsyndromic isolated craniosynostosis: (1) a resective type of treatment of the fused cranial suture to allow unrestricted growth of the brain and subsequent correction of the cranial dysmorphology with natural brain growth and (2) a reconstructive type of procedure that addresses the skeletal dysmorphology directly to restore an appropriate anatomic form. The surgical team should be composed of a pediatric craniofacial surgeon and a pediatric neurosurgeon for optimal results.
To use the first type of surgical management, strip craniectomy of the prematurely fused suture, it is important to use postoperative orthotic (helmet) therapy to shape the skull. Such techniques rely on the intrinsic growth potential of the brain, and experience has demonstrated that the best results for correction of the skeletal dysmorphology must incorporate helmet therapy postoperatively. Removal of the affected suture can be done endoscopically or under direct visualization with minimal incisions required for access. This typically allows for less blood loss and is completed between 2 to 6 months of age to take advantage of growth potential. Various modifications, including barrel staving of the surrounding cranial bone, may assist with cranial molding and expansion postoperatively. It should be noted that postoperative helmet therapy is needed generally 23 hours a day and typically requires 9 to 12 months of use, which can be cumbersome for families.
A similar approach that allows for removal of the fused suture but assists in selective expansion of the skull and molding postoperatively is the use of springs placed at the craniectomy site. Such springs mold the cranial bones in an “active” manner rather than a “passive” manner as is the case with helmet therapy. The use of spring-assisted cranial vault expansion allows for a less invasive approach to cranial reconstruction and allows for expansion in patients who are slightly older than the typical age range for endoscopic techniques and postoperative helmet therapy. Patients may be treated at the ages of 3 to 8 months more reliably than with endoscopic techniques. However, the use of springs can be technique sensitive and requires a second general anesthetic for removal of the springs. Displacement of the springs during treatment can be a significant problem.
Modern reconstructive-type procedures to address nonsyndromic craniosynostosis include a formal craniotomy performed by a neurosurgeon and simultaneous skeletal reconstruction by the craniofacial surgeon. Reconstruction and reshaping include the removal, dismantling, and reassembly of all dysmorphic skeletal components into an anatomically desirable shape. The extent of the surgery depends on the suture or sutures involved and the resultant skeletal deformity. The choice of surgical technique may often be dictated by the timing of patient presentation as well as family desires. If a patient presents initially at the age of 7 months of age, for example, with isolated sagittal suture craniosynostosis, endoscopic techniques with postoperative helmet therapy would be less predictable for correction of the skeletal dysmorphology. Cranial vault reconstruction therefore should be a consideration for such patients. When reconstructive-type procedures are performed, the patient should be older during the first year of life to allow for more predictable long-term results. Growth potential and healing capacity are at their best during the first year of life, but it should be noted that there is essentially no significant increased risk of increased ICP that has been demonstrated in patients with isolated nonsyndromic craniosynostosis before 1 year of life, so waiting until that time may be helpful for some patients. All patients with craniosynostosis should undergo evaluation with neuro-ophthalmology for any signs of potential increased ICP that may be related in part to the premature closure of cranial sutures. Older patients generally tolerate anesthesia better and have a larger blood volume, which is important because the need for blood transfusion during cranial vault reconstruction is common. Slightly older patients also allow for more stable cranial bone fixation, which is usually completed with the use of resorbable plates and screws or sutures.
There are various methods for cranial vault reconstruction. To treat nonsyndromic sagittal suture craniosynostosis in the example presented, a common management strategy involves treating the posterior two-thirds of the cranial vault to provide expansion and allow appropriate brain growth and potentially improve cerebrospinal fluid (CSF) and venous dynamics. It is important to note that the dysmorphology of sagittal suture craniosynostosis is primarily biparietal narrowing, AP elongation, loss of posterior cranial vertical height, and compensatory bifrontal bossing. For many patients, a reconstructive plan that focuses primarily on the posterior cranial vault for biparietal expansion, improvement of posterior vertical cranial height, and to a lesser degree decreases the AP elongation is sufficient for addressing the cranial dysmorphology. Frontal bone compensatory bossing often improves significantly throughout cranial growth, which continues until approximately 6 years of age when it is more than 90% complete. Thus, treating the posterior two-thirds of the cranial vault may optimize the risks and benefits of other techniques such as total calvarial reconstruction, which may involve more significant blood loss, longer surgery, and potentially increased morbidity for the patient. Some centers elect to treat both the anterior and posterior cranial vaults in two separate surgeries separated by a short period of time. Such general risks are inherent to any cranial vault reconstruction, and one method is not suitable for all patients who present with craniosynostosis. A potential method for such cranial vault reconstruction is presented in Figs. 93.2 to 93.4 .
