PURPOSE: Aesthetic deterioration after surgical treatment of metopic craniosynostosis may manifest as bitemporal hollowing (TH), lateral orbital retrusion (LOR), or frontal bone irregularities (FBI). Patients with these complications have reoperation rates of 18-46%. To date, there have been few longitudinal studies assessing the effect of pre-operative dysmorphology on aesthetic outcomes in this cohort. This study evaluates the relationship between metopic severity, including the use of CranioRateTM, a novel metopic synostosis severity measure, and mid-term aesthetic outcomes. MATERIALS AND METHODS: Patients with non-syndromic metopic craniosynostosis who underwent bi-frontal orbital advancement and remodeling (BFOAR) between 2012 and 2017 were reviewed. Metopic synostosis severity was determined based on pre-operative CT assessment of IFA and CranioRateTM. CranioRateTM is a machine learning algorithm trained to recognize morphologic features of metopic synostosis and generate quantitative severity ratings including metopic severity score (MSS) and cranial morphology deviation (CMD). Frontal and lateral photographs of patients with at least four years post-operative follow-up were assessed by attending craniofacial surgeons using masked three-rater aesthetic grading of clinical photos (n=39). Graders assessed Whitaker score as well as the presence of TH, LOR, FBI, or a ‘catch-all’ category of visible irregularities. Binary logistic regression was used to assess predictors of TH, LOR, FBI, and VI. Multinomial logistic regression was used to assess predictors of Whitaker classification. RESULTS: The average age at preoperative CT scan was 7.7 ± 3.4 months and the average age at BFOAR was 9.9 ± 3.1 months. The average MSS was 6.3 ± 2.7 out of 10 and average CMD was 200.4 ± 44.7 out of 300. Average IFA for the cohort was 116.8° ± 13.8° (range 93° - 138°). The average time from operation to aesthetic assessment was 5.4 ± 1.0 years (range 4.1 – 7.8 years). ‘Any visible irregularity’ was present in 87.2% (n = 34) of patients, temporal hollowing in 76.9% (n = 30), frontal bone irregularities in 61.5% (n = 24), and lateral orbital retrusion in 20.5% (n = 8). Most patients received a median Whitaker classification of II (61.5%, n =24), followed by class III (23.1%, n = 9). There was a significant association between MSS and age at CT scan, with younger patients having more severe metopic severity scores (r = -.451, p = .004). Similarly, MSS and IFA were negatively associated, with a higher MSS correlating to a lower IFA (r = -.371, p = .034). MSS was found to be the only independent predictor of visible irregularities (OR 2.18, B = .780, p = .024). Decreased age at surgery (OR, 1.08; 95% CI, 1.05 to 2.6, p = .002) and increased length of follow up (OR, 1.59; 95% CI, 1.59 to 3.54, p <.001) were significantly associated with a worse median Whitaker score. No impact of surgical technique, including parietal bone graft use or interpositional bone graft size, was demonstrated (p > .05 for both). CONCLUSION: More severe cases of metopic craniosynostosis show increased rates of cumulative aesthetic dysmorphologies. Measures of pre-operative metopic severity are predictive of mid-term aesthetic outcomes.
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