Cephalic index correlates poorly with intracranial volume in non-syndromic scaphocephalic patients

Objectives

This study aims to compare pre- and postoperative cephalic indexes (CI) with corresponding segmented intracranial volumes (SIV) obtained from volumetric CT in scaphocephalic patients.

Methods

Twenty-four patients (17 boys) who had undergone cranial vault remodeling due to scaphocephaly were compared from 3D-CT imaging datasets. The mean age of the patients at preoperative CT imaging was 5.5 months, and that at 1-year postoperative imaging, 21.5 months. The mean interval between preoperative CT imaging and surgery was 3.3 months. Pearson’s correlation was used to test the correlation of both pre- and postoperative CI with SIV. A paired t test was used to compare differences in the pre- and postoperative mean values of CI and SIV.

Results and discussion

CI correlated poorly with intracranial volume both preoperatively (r?=?0.274) and postoperatively (r?=?0.128). The mean preoperative CI was 65.92 (range 57.99–73.97), and the mean postoperative, CI 70.24 (range 60.23–75.57). The mean preoperative intracranial volume was 877.79 cm³ (range 638–1,256), and the 1-year postoperative volume, 1,249.04 cm³ (range 1,039–1,529). The mean values of both CI and SIV increased significantly after surgery. In one patient, the CI in postoperative measurements was smaller, whereas in all patients, the postoperative SIV was larger than the preoperative intracranial volume. The mean percentage increase in CI was 6.6 %, whereas the mean increase in SIV was 43.1 %.

Conclusion

Cephalic index correlates poorly with intracranial volume in non-syndromic scaphocephalic patients. For some patients, surgery and growth resulted in only subtle or no change in CI despite a notable increase in intracranial volume.