Craniosynostosis, the premature fusion of one or more cranial sutures, may occur in isolation or in association with a syndromic constellation. Multiple-suture synostosis has consistently been associated with brain compression and increased intracranial pressure, and frequently decreased cognitive development. Single-suture craniosynostosis, however, has been thought by some to be an aesthetic problem with infrequent consequences on brain function and development. Some studies have disputed this concept and have argued a correlation between single-suture craniosynostosis and abnormalities in development. The purpose of this study was to determine, using an objective radiographic tool, positron emission tomography scans, if patients with single-suture craniosynostosis had any abnormalities in cerebral glucose metabolism that would indicate changes in local brain function. A total of 10 children with single-suture craniosynostosis, eight males and two females, ranging in age from 0.1 to 3.2 years, were enrolled in this prospective study approved by the Internal Review Board. Six of the children had sagittal synostosis, three had metopic synostosis, and one had coronal craniosynostosis. Each of the patients had preoperative positron emission tomography scans performed 1 to 5 weeks before cranial reconstructive surgery and postoperative scans at 6 to 12 weeks after surgery. Surgical treatment consisted of cranial vault remodeling in eight of the children and strip craniectomy with cranial expansion in two of the children. After surgery, the two scans were compared qualitatively and quantitatively by a single radiologist. The results demonstrated variable regional increases and decreases in local postoperative cerebral glucose metabolism. However, in the posterior occipital region, the area of visual development and visual spatial coordination, there was a consistent postoperative increase in all 10 patients. Maximum glucose metabolic rate was increased up to 30.2% with a mean of 9.9%, and average glucose metabolic rates demonstrated a maximum increase of up to 18.8%. The results of this study indicate cerebral glucose metabolism consistently increases in the posterior occipital cortex after surgical release of single-suture craniosynostosis. Future developmental studies are being performed to examine the functional consequences of these metabolic changes.
© 1999 Mutaz B. Habal, MD