A 2-month-old infant with craniosynostoses is scheduled for a preoperative CT scan.
Syndromes: This patient may have isolated, nonsyndromic craniosynostoses, or the craniosynostoses may be a component of one of the acrocephalosyndactyly syndromes (ACSs), which include:
Craniosynostosis is caused by premature closure of the cranial sutures and an associated growth arrest perpendicular to the involved suture line, resulting in a skull deformity that progresses over time until growth is completed. It is therefore important that this issue be surgically addressed early in infancy. It may be part of the previously noted syndromic paradigm, which is associated with brachydactyly (foreshortened extremities), syndactyly (fusion of the phalanges and obliteration of the natural web spaces), and polydactyly (extra digits). There is a great deal of overlap of phenotypic expression among these subtypes. Craniosynostosis may be caused by a new mutation or display either an autosomal dominant or recessive genetic pattern of inheritance. There is evidence of defects in fibroblast growth factor regions (FGFR) of the genome, resulting in abnormal bridging ossification of mesenchymal tissue.
Any suture may be involved (sagittal, coronal, or metopic), and in some cases more than one suture may be involved. Patients may be at risk of increased intracranial pressure: with one fused suture, there is a 15% risk; with more than one fused suture, the risk increases to approximately 35%.
Procedures include open strip craniectomy, endoscopic craniectomy, cranial vault remodeling, and spring-assisted cranioplasty.
For many of these young patients presenting for a CT scan, anesthesia is not required. The procedure itself is short and not uncomfortable. A brief period of sleep or nap deprivation, followed by feeding and swaddling just prior to the scan, will allow the patient to fall asleep naturally. The head may need to be taped in a neutral position, and several folded blankets may be placed against the side of the head to minimize movement.
Anesthetic considerations for general anesthesia for a more extensive scan or surgical repair require a thorough evaluation of the upper airway, lower respiratory tract, and cardiovascular system are as follows:
Head size and shape. This will determine the proper positioning for assuring a good natural airway, proper mask ventilation, and optimal intubating conditions. Obtaining a sniffing position or a somewhat extended neck position may be a challenge if there is a prominent occiput or significant asymmetry. A neck roll or shoulder roll may be helpful. Patients with type 2 ACS have maxillary hypoplasia, which may cause difficulties with mask ventilation. Improvement in the mask seal may require choosing alternative mask sizes and mask cushion inflation pressure; occasionally, positioning the mask with the apex down can allow for a better seal. Nasopharyngeal hypoplasia and palatal anomalies must ...