Frontal Sinus Volume and Frontal Bar Position Are Associated in Unicoronal Craniosynostosis.

BACKGROUND

Frontal sinus pneumatization plays an important role in brow protrusion, and absence of frontal sinus development may be associated with brow retrusion. Using unicoronal craniosynostosis as a model, the authors studied the relationship among frontal sinus volume, supraorbital retrusion, and brow position.

METHODS

The authors conducted a retrospective review of unicoronal craniosynostosis patients with head computed tomographic scans and photographs taken from ages 5 to 18 years. Frontal sinus volume and supraorbital retrusion were calculated using three-dimensional computed tomographic reconstructions. A "brow score" from 0 to 3 was assigned to each patient's photographs by a consensus of two craniofacial surgeons; sinus morphology and brow scores were compared.

RESULTS

The study included 20 unicoronal craniosynostosis patients. The affected side demonstrated increased retrusion (7.1 ± 3.7 mm versus 3.0 ± 3.1 mm; p < 0.001) and decreased frontal sinus volume (0.8 ± 0.9 cc versus 2.6 ± 1.8 cc; p < 0.001). Qualitative brow retrusion scores differed between affected and unaffected sides (score of 0, 17 percent affected versus 78 percent unaffected; score of 1, 28 percent versus 22 percent; score of 2, 39 percent versus 0 percent; and score of 3, 17 percent versus 0 percent; p < 0.001). Brow scores trended with retrusion measurements (score of 0, 2.7 ± 2.9 mm retrusion; score of 1, 6.1 ± 3.5 mm; score of 2, 8.9 ± 3.2 mm; and score of 3, 9.7 ± 2.8 mm; p < 0.001). Subjects with brow scores of 0 or 1 had larger frontal sinus volumes than subjects with brow scores of 2 or 3 (p = 0.018).

CONCLUSIONS

Qualitative brow retrusion correlates strongly with both quantitative supraorbital retrusion and frontal sinus volume. Although this retrospective study cannot prove causality, which is likely multifactorial, its strong correlation with frontal sinus pneumatization highlights the importance of the frontal sinus in brow position in unicoronal craniosynostosis.

CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.