Persistent Metopic Suture: Incidence and Clinical Correlates in a Large Southeast Asian Population

The metopic suture usually fuses by age 2, but persistence beyond this age (metopism) is uncommon and may mimic a fracture or signal disordered craniofacial development. The authors assessed the incidence of persistent metopic sutures and associated demographic and clinical factors. A retrospective study was organised of cranial CT scans of patients aged 24 months or older at Siriraj Hospital, Bangkok, Thailand, classifying metopic patency with the Lottering system and defining persistence as any patency beyond 24 months. The authors collected data on age, sex, cephalic index, imaging indication, developmental delay, and anterior fontanel closure. Among 1315 patients (63.8% males; median age 12.3 y), 3.3% (44 patients) had a persistent metopic suture, including 2 (0.15%) with complete patency and 42 (3.2%) partial. Sex, age, cephalic index, and imaging indications did not differ significantly between groups. Delayed frontal sinus development was more prevalent in patients with persistence (11.4% versus 2.7%), as was delayed anterior fontanel closure (4.5% versus 0.4%). In multivariable logistic regression, delayed frontal sinus development (odds ratio: 4.7; P = 0.002) and delayed anterior fontanel closure (odds ratio: 12.0; P = 0.03) independently predicted persistence. In conclusion, the incidence of persistent metopic suture was around 3% in contemporary Thai population. Although no sex or age predilection emerged, persistence was strongly associated with delayed frontal sinus development and delayed anterior fontanel ossification.