Temporal Deformity Objectively Measured Before and After Surgery for Metopic Synostosis: Retrusion Rather than Hollowing
The temporal contour deformity typical of metopic synostosis is often referred to as temporal hollowing, but has not been quantitatively defined. This deformity is present before surgery and remains to a varying extent at long-term follow-up. The present study aimed to objectively evaluate the degree of this contour deformity in metopic synostosis before and after surgical correction.
All children surgically treated for metopic synostosis at Sahlgrenska University Hospital between 2002 and 2014 (n = 120) with appropriate computed tomography scans (n = 160) performed preoperatively and/or at follow-up at 3 years of age were included. Depending on age, 1 of 2 surgical techniques was used. Children presenting before the age of 6 months were treated with frontal remodeling in combination with a spring (S group), whereas children older than 6 months were treated with a bone transplant (BT group). The bony temporal deformity was measured with a semiautomatic MATLAB program and patients were compared to sex- and age-matched controls.
The deformity was significantly reduced in both groups (P < 0.001). In the S group, it was reduced from a mean ± standard deviation of 3.6 ± 1.9% to 1.0 ± 1.2% and in the BT group, it was reduced from 3.3% ± 1.4% to 1.1% ± 0.8%.
The contour deformity in metopic synostosis is present both before and after surgery and should therefore be termed temporal retrusion (TR). This assessment method enables objective comparison of TR before and after surgical correction and is a potential tool to evaluate TR in metopic synostosis.