Surgical Outcomes in Sagittal Craniosynostosis

The overarching aim of this thesis was to increase the understanding of patient and treatment related factors behind the variability in morphological outcomes seen in nonsyndromic sagittal craniosynostosis. There is a lack of knowledge regarding patient related predictors for the variability in outcomes, and consensus has yet to be reached regarding best practice with respect to surgical technique for the treatment of sagittal craniosynostosis. There is also a lack of objective outcome measures which further complicates evaluation and interpretation of outcomes. The studies included in this thesis analyze outcomes after early surgery for Nonsyndromic Sagittal Craniosynostosis (SC). Softwares for advanced image analysis were used to analyze cranial morphological changes from surgery and growth. Division of the total intracranial volume into three partial volumes (anterior, middle and posterior) was proposed as a means to further quantify the deformity seen in SC. The method detected differences that the conventionally used Cranial Index (CI) could not, adding further information when comparing data sets. Secondary Coronal Synostosis was evaluated. The finding was known to correlate to less growth of head circumference. We found that it further correlated with less growth of intracranial volume due to less growth in the posterior part of the skull. It also correlated to diffuse gyral impressions, a finding known to implicate raised intracranial pressure. Due to less growth in the anteroposterior plane, the patients who developed secondary coronal synostosis had a larger correction of scaphocephaly. Two cohorts having undergone H-Craniectomy for SC from Uppsala and Helsinki were studied. The Helsinki group had undergone an extended surgical version adding coronal suturectomies and posterior barrel staves with the aim to further correct the deformity. The Helsinki group were more scaphocephalic preoperatively, the cause of which is currently unexplained. The groups converged in CI postoperatively. Consequently, the Helsinki group, having undergone a more extended technique, had a larger correction. Further analysis implied that this was mainly due to the fact that a more severe preoperative deformity allows for a larger correction. Extending the H-Craniectomy technique could play a role in treating patients presenting with a more extreme deformity. Artificial Intelligences, in the form of neural networks, able to analyze total intracranial volume and segment separate cranial bones were established. The aim was to enable objective, efficient image analysis in order to manage large data sets in future multicenter studies. The H-Craniectomy technique used in Uppsala was compared to the Spring-assisted Surgery technique used in Gothenburg in a series of cases matched for sex and preoperative CI. The Spring-assisted Surgery group had a larger correction of CI and more shift of intracranial volume posteriorly without there being any difference in total intracranial volume. Taken together, this implies that Spring-assisted Surgery offers a greater correction of the scaphocephalic deformity compared to H-Craniectomy. Based on these results, the Uppsala Craniofacial Center subsequently altered their surgical protocol to Spring-assisted Surgery