Date of Award

January 2023

Document Type

Thesis

Degree Name

Medical Doctor (MD)

Department

Medicine

First Advisor

Michael Alperovich

Abstract

The cranial morphology of single-suture metopic craniosynostosis is defined by trigonocephaly, hypotelorism, and bitemporal narrowing. The severity of deformity may be defined radiographically based on computed tomography imaging. The radiographic severity of metopic synostosis has been suggested as a possible predictor of long-term neurocognitive outcomes, making it a potentially useful variable in determining which patients will benefit from surgery. Artificial intelligence (AI) has recently been used to quantify severity of metopic synostosis. Furthermore, age at surgery has been shown predict long-term neurocognition in sagittal synostosis but has not been adequately explored in metopic synostosis. In sagittal synostosis, age at surgery of less than 6 months is associated with better neurocognitive outcomes at school age. Our goal in the present study is to assess the association of radiographic severity and age at surgery with neurocognitive outcomes at school age with the hypothesis that more severe phenotype and older age at surgery will associate with lower neurocognitive scores. To that end, children ages 6 to 18 years old who had received surgical correction for metopic synostosis underwent testing of intelligence quotient (IQ), academic achievement, and visuomotor integration (VMI). Manual measurements of severity including endocranial bifrontal angle (EBA), adjusted EBA (aEBA), frontal angle (FA), and bitemporal/biparietal diameter ratio (BT/BP ratio) and AI-derived metopic severity scores (MSS) and cranial morphology deviation scores (CMD) were determined. Scans were categorized as moderate (EBA > 1240) or severe (EBA < 1240) for head-to-head group comparisons and multivariate linear regressions were used to assess the relationship of age at surgery and severity with neurocognitive outcomes. 41 patients with average age at surgery 8.9 ± 6.7 months and average age at testing 10.8 ± 3.4 years old were included. Patients in the severe group received surgery at an earlier average age (6.6 ± 2.7 vs 10.6 ± 8.4 months, p = 0.062). There were no significant differences in test scores between severe and moderate cohorts. Multivariate linear regression models identified significant associations between MSS and CMD scores and reading comprehension (p = 0.040 and 0.018, respectively) and reading composite scores (p = 0.024 and p = 0.008, respectively). Age at surgery was significantly associated with VMI in all of six models controlling for each individual severity measure (p-values ranging from 0.017 to 0.045) and reading composite scores in models controlling for MSS and CMD scores (p = 0.047 and 0.019, respectively). This study suggests an association between pre-operative radiographic severity of metopic synostosis with reading ability and age at surgery with reading ability and visuomotor integration at school age. AI-derived MSS and CMD scores in particular associated with reading outcomes. Severity and age at surgery were not significantly associated with other testing domains including IQ. Prompt surgical correction of metopic synostosis in this cohort may have mitigated neurodevelopmental differences based on severity which have been described preoperatively.

Comments

This thesis is restricted to Yale network users only. It will be made publicly available on 07/24/2025

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