The timing of physiologic closure of the metopic suture: a review of 159 patients using reconstructed 3D CT scans of the craniofacial region.

PURPOSE: The purpose of this study was to determine the normal physiologic timing of the closure of the metopic suture in non-craniosynostotic patients.
METHODS: This clinical study involved a consecutive series of infants and young children who underwent 3D CT-scan evaluation for deformational plagiocephaly or suspected traumatic head injury. All patients with evidence of craniosynostosis were excluded from the study. Every infant and child referred to our Craniofacial Team for deformational plagiocephaly between 1997 and 2000 (n = 84) received a baseline pre-treatment 3D CT-scan of the head. Our study also included a series of selected pediatric trauma patients (1 to 24 months of age) between 1997 and 2000 (n = 75) who received CT-scan to rule out head injury. The CT scan results were reviewed for closure of metopic suture by a single observer.
RESULTS: The earliest evidence of metopic suture closure was at 3 months, the age at which 33% of patients (4/12) were closed. At 5 months of age, 59% (13/22) of sutures were closed. At 7 months of age, 65% (15/23) were closed. At 9 months of age, 100% (10/10) were closed. All patients greater than 9 months of age within the study had complete metopic suture closure.
CONCLUSION: Our findings suggest that normal or physiologic closure of the metopic suture occurs much earlier than what has been previously described. This study establishes that metopic fusion may normally occur as early as 3 months of age, and that complete fusion occurred by 9 months of age in all patients in our series. Therefore, 3-D CT scans showing complete closure of the metopic suture at an early age (3 to 9 months) cannot be considered as evidence of metopic synostosis, and thus, should not be the decisive factor for early surgical intervention.