The formation of the cranial sutures, in utero, occurs when the ossification of the skull bones reaches predestined positions around gestational week 15 to 20. Craniosynostosis, and the consequent skull shape deformities, is treated with surgery including osteotomies of the fused sutures. The occasional appearance of a new suture in the osteotomy lines has previously been described as sporadic events. In this retrospective study, a 4-year consecutive series of osteotomies combined with springs for craniosynostosis were systematically analysed regarding the appearance of neosutures. In total, 84 patients were included and in 16 patients (19%) a new radiologically normal suture appeared in a part of the suture that was completely closed preoperatively. Additionally, in 7 patients (8%) a new suture appeared in a part of the suture that had a discernible suture prior to surgery.In conclusion, in this consecutive and well-defined patient cohort operated for craniosynostosis, the formation of a neosuture is not a rare, and speculatively not a random, event. The appearance of a new suture long after the normal time period for suture formation in utero indicates that the craniosynostosis may just as well be caused by disturbed formation of the suture as actual premature closure.