A patient with unicoronal craniosynostosis was treated by an open cranial vault remodeling procedure at 11 months of age. A calvarial defect persists at the site of the sagittal suture at 7 years follow-up. This unexpected outcome led us to evaluate current literature on incidence and possible causes of incomplete reossification after craniosynostosis surgery.English literature was searched from 1982 to 2013. Variables of interest were incidence, diagnose, type of surgery, age at operation, possible causes for incomplete reossification, and duration and type of follow-up.Incidence in unselected cohorts ranged from 0.5% to 18.2%. Incomplete reossification has been reported in syndromical and nonsyndromical cases, after multiple types of surgery for any type of suture. Follow-up was done by palpation, radiology or both, for a period of 6 to 264 months.Higher age at operation and a dura tear are associated with an increased risk of incomplete reossification.Type and duration of follow-up is inhomogeneous and there is a wide variety in the terminology used for incomplete reossification.To improve international communication on this topic, more long-term studies, using a consistent type and length of follow-up and uniform terminology are needed.