Delayed Presentation of Sagittal Synostosis Phenotypes
Rishi N. Modi B.S.1, Caitlyn C. Belza B.S.1, George N. Kamel M.D.2,3, Mary K. Carbullido B.S.4, Burçin Ataseven Ph.D.5, Amanda A. Gosman, M.D.1,2 1UC San Diego School of Medicine, San Diego, CA 2UC San Diego Division of Plastic Surgery, San Diego, CA 3Rady Children's Hospital, San Diego, CA 4University of Wisconsin School of Medicine and Public Health, Madison, WI 5Istanbul Kültür University, Istanbul, Turkey
Background: Sagittal craniosynostosis has a prevalence of 1 in 2000 live births. Sagittal suture fusion commonly presents as dolichocephaly, which is a disproportionate elongation of the skull. Rarely, it results in clinocephaly; a "saddle-shaped" phenotype with frontal bossing, midvault depression, and a short, narrow, anvil-like posterior cranium. This saddle phenotype may be less detectable on physical exam, leading to delayed presentation. Fusion of the minor sutures, i.e. squamous and sphenoid, has been concurrently noted with major suture synostosis, but literature is inconclusive on significance. This project aimed to characterize clinically relevant differences between sagittal synostosis phenotypes and examine the etiology of the delay in presentation.
Methods: An IRB approved retrospective chart review was performed with patients from January 1999 to November 2018 at a single institution, including patients with single-suture sagittal craniosynostosis. Sub-phenotype and minor suture fusion were assessed by computed tomography. Developmental delay diagnoses (speech/language or global) were confirmed with physician notes. Analyses examined correlations between sub-phenotype, time of presentation, minor suture fusion, developmental delay, and operative technique.
Results: 160 patients diagnosed with single-suture sagittal craniosynostosis patients were identified. 30.6% had a saddle phenotype (n = 49) and 69.4% had dolichocephaly (n = 111). Chi-square analysis demonstrated that 30.6% of patients with the saddle phenotype presented with a developmental delay, while 12.6% of dolichocephalic patients presented with a developmental delay (p = 0.006). Chi-square analysis also revealed 77.6% of the saddle cohort had at least one minor suture fused (p < 0.001), and 58.6% of sagittal synostosis patients with developmental delay had at least one minor suture fused (p = 0.052). Independent t-test showed patients with the saddle phenotype presented for surgery at an average age of 23.216 ± 23.056 months, which was significantly older (p < 0.001) than their dolichocephalic counterparts (6.222 ± 8.079 months). Within the saddle cohort, 75.5% underwent open cranial vault repair whereas 18% of the dolichocephalic cohort underwent open cranial vault repair. The saddle cohort had estimated blood loss per kilogram (11.730 ± 8.419 cc/kg) which was significantly greater (p = 0.001) compared to the dolichocephalic cohort (7.171 ± 7.043 cc/kg). The saddle cohort required a higher (p = 0.017) volume of packed red blood cell transfusion (15.821 ± 12.085 cc/kg) than the dolichocephalic cohort (10.925 ± 11.622 cc.kg). The saddle cohort also required longer (p < 0.001) surgery time (164.88 ± 62.918 min) than the dolichocephalic cohort (98.49 ± 69.240 min).
Conclusion: This study highlights difficulties in diagnosing sagittal craniosynostosis, and shows that developmental delay may be the initial presentation of the saddle phenotype. The saddle phenotype also correlated with fusion of the minor squamous and sphenoid sutures. The link between developmental delay and minor suture fusion was notable, and should be explored with a larger sample size. Patients with saddle sagittal synostosis subsequently present for surgery at an older age than dolichocephalic patients, and therefore are more likely to receive open cranial vault repair, with a taxing intraoperative experience characterized by increased blood loss, increased transfusions, and longer operation time.
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