New insights into the relationship between skull base fusion and torticollis in children

UPF-PIOS is an underrecognized cause of torticollis in young children. Its characteristic clinical features include an asymmetrical posterior skull base, shortening of the skull on the affected side, and a head tilt toward the side of the prematurely fused synchondrosis. Recognizing this pattern-a tetrad of unilateral synchondrosis fusion and the three resultant findings-is clinically important for differential diagnosis. Considering UPF-PIOS in children with torticollis (especially when physical therapy fails) can prevent misdiagnosis (e.g., distinguishing it from lambdoid craniosynostosis) and guide appropriate management. Further research with larger cohorts and long-term follow-up is warranted to confirm these findings.