Object. There is still controversy regarding the optimum time to perform su
rgery for craniosynostosis. Some recommend surgery soon after birth and oth
ers delay until the age of 12 months. Intracranial pressure has been measur
ed in an attempt to provide a scientific rationale, but many questions rema
in unanswered. To date, little attention has been given to intracranial vol
ume and its changes during the first few years of life in children with cra
niosynostosis. The authors' goal was to focus on intracranial volume during
this period and to compare measurements obtained in patients with craniosy
nostosis with measurements obtained in healthy individuals.
Methods. Using the technique of segmentation, the intracranial Volume of 84
children with various forms of craniosynostosis was measured on preoperati
ve computerized tomography scans. The change in average volume that occurs
with increasing age was calculated and compared with a model of normal intr
acranial volume growth. The age at presentation for children with craniosyn
ostosis was 1 to 39 months; 76% of the patients were younger than 12 months
. In eight patients in whom only one cranial expansion procedure was perfor
med, postoperative intracranial volumes were measured as well. Several inte
resting observations emerged. 1) There was little difference in head growth
between boys and girls with craniosynostosis during the first few months o
f life. After the age of 12 months, however, the difference in intracranial
volume normally seen between the two genders was observed in the craniosyn
ostosis group as well. 2) Excluding children with complex pansynostosis, wh
o have smaller heads, children with all other types of craniosynostosis hav
e similar head growth after the Ist year of life, with no difference betwee
n the number of and type of suture affected. Children with Apert's syndrome
develop greater than normal intracranial volumes after the Ist year of lif
e. 3) Although children with craniosynostosis are born with a smaller intra
cranial volume, by the age of 6 months volume has reached normal levels, an
d from that point on volume follows the pattern of normal head growth. 4) C
hildren who presented after the age of 6 months and later developed recurre
nt craniosynostosis after initial successful treatment had a small intracra
nial Volume at their initial presentation. 5) Of the patients whose postope
rative intracranial volumes were measured, all but one had preoperative vol
umes at or above normal values, and their postoperative volumes were consid
erably higher than normal for their age. These children all followed a grow
th curve parallel to that of healthy children but at higher volume value. O
ne patient with a smaller-than-normal initial intracranial volume was surgi
cally treated at a very young age and, despite cranial expansion surgery, p
ostoperative volume did not reach normal levels. It is postulated that this
was due to the fact that the operation was performed at a time when cranio
synostosis was still active.
Conclusions. The results of this study indicate that the underlying mechani
sm leading to craniosynostosis and constriction of head volume "exhausts" i
ts effect during the first few months of life. Measurement of intracranial
volume in clinical practice could be used to "fine tune" the optimum time f
or surgery. In late-presenting children, this may be useful in predicting p
ossible recurrence.