What can a morphometric study of unoperated children teach us about the natural history of metopic synostosis?

Outcomes of surgical repair of trigonocephaly are well reported in the literature, but there is a paucity of information on the natural history of unoperated children. The authors evaluated a group of unoperated children with metopic synostosis to describe the natural change in head shape over time. A database was screened for scans of children with unoperated trigonocephaly (2010-2021). Multisuture cases and those with a metopic ridge were excluded. Three-dimensional surface scans (3D stereophotogrammetry/CT) were used for morphological analysis. Nine previously published parameters were used: frontal angle (FA30°), anteroposterior (AP) volume ratio (APVR), AP area ratio (APAR), AP width ratios 1 and 2 (APWR1 and APWR2), and 4 AP diagonal ratios (30° right APDR [rAPDR30], 30° left APDR [lAPDR30], 60° right APDR [rAPDR60], and 60° left APDR [lAPDR60]). Ninety-seven scans were identified from a cohort of 316 patients with a single metopic suture, in which the male-to-female ratio was 2.7:1. Ages at the time of the scan ranged from 9 days to 11 years and were stratified into 4 groups: group 1, 3 years. Significant improvements were detected in 5 parameters (APVR, APAR, APWR1, rAPDR30, and lAPDR30) over time, whereas no significant differences were found in FA30, APWR2, rAPDR60, and lAPDR60 between age groups. Forehead shape (surface area and volume), as well as narrowing and anterolateral contour at the frontal points, differed significantly over time without surgery. However, forehead angulation, narrowing, and anterolateral contour at temporal points did not show significant differences. This knowledge will aid in surgical and parental decision-making

Lack of association of cranial lacunae with intracranial hypertension in children with Crouzon syndrome and Apert syndrome: a 3D morphometric quantitative analysis

Purpose Cranial lacunae (foci of attenuated calvarial bone) are CT equivalents ofBcopper beating seen on plain skull radio-graphs in children with craniosynostosis. The qualitative presence of copper beating has not been found to be useful for the diagnosis of intracranial hypertension (IH) in these patients. 3D morphometric analysis (3DMA) allows a more systematic and quantitative assessment of calvarial attenuation. We used 3DMA to examine the relationship between cranial lacunae and IH in children with Crouzon and Apert syndromic craniosynostosis

A population-specific material model for sagittal craniosynostosis to predict surgical shape outcomes

Sagittal craniosynostosis consists of premature fusion (ossification) of the sagittal suture during infancy, resulting in head deformity and brain growth restriction. Spring-assisted cranioplasty (SAC) entails skull incisions to free the fused suture and insertion of two springs (metallic distractors) to promote cranial reshaping. Although safe and effective, SAC outcomes remain uncertain. We aimed hereby to obtain and validate a skull material model for SAC outcome prediction. Computed tomography data relative to 18 patients were processed to simulate surgical cuts and spring location. A rescaling model for age matching was created using retrospective data and validated. Design of experiments was used to assess the effect of different material property parameters on the model output. Subsequent material optimization—using retrospective clinical spring measurements—was performed for nine patients. A population-derived material model was obtained and applied to the whole population. Results showed that bone Young’s modulus and relaxation modulus had the largest effect on the model predictions: the use of the population-derived material model had a negligible effect on improving the prediction of on-table opening while significantly improved the prediction of spring kinematics at follow-up. The model was validated using on-table 3D scans for nine patients: the predicted head shape approximated within 2 mm the 3D scan model in 80% of the surface points, in 8 out of 9 patients. The accuracy and reliability of the developed computational model of SAC were increased using population data: this tool is now ready for prospective clinical application

Objective evidence for the use of polylactic acid implants in HIV-associated facial lipoatrophy using three-dimensional surface laser scanning and psychological assessment

The advent of highly active antiretroviral therapy (HAART) has dramatically improved the life expectancy of people infected with human immunodeficiency virus (HIV). Although patients often have excellent disease control with these combinations of antiretrovirals, they are at risk for the multiple toxicities associated with these drugs. Facial lipoatrophy is a particularly distressing complication of some HAART regimes. This disfigurement can lead to significant psychosocial stress, resulting in decreased treatment compliance. Polylactic acid (PLA) facial implants provide a potential method of restoring a normal appearance. One hundred consecutive patients had a course of PLA facial implants. All patients were assessed clinically and had photographs, facial surface laser scans and completed psychological questionnaires throughout the course of treatment. After a mean of 4.85 treatments per patient, there were improvements in all measures. The mean clinical scores improved from a moderate-severe grade to none-mild grade after treatment. Three-dimensional (3D) laser surface scans showed a volume increase of 2.81 cc over the treated area of the cheek. There were significant improvements in all of the psychological measures. This study shows clear objective evidence of the psychological and physical benefit of PLA implants in HIV-associated facial lipodystrophy. © 2008 British Association of Plastic, Reconstructive and Aesthetic Surgeons

A quantitative comparison of psychological and emotional health measures in 360 plastic surgery candidates: Is there a difference between aesthetic and reconstructive patients?

This study examines the utility of the aesthetic and reconstructive categorization for making treatment decisions in patients seeking facial surgery. A total of 360 patients with aesthetic or combined functional aesthetic deficits were included. Validated psychological scales were used as outcome measures. All subjects showed clinically significant levels of appearance-related distress, with highest levels in the aesthetic and lowest levels in the functionally impaired group. Significant gender differences were not found on any psychological measures. A small negative correlation was found between age and distress. These findings challenge the validity of restricting treatment on the basis of an aesthetic distinction, since this is the group demonstrating the highest level of need. Neither age nor gender is a reliable discriminator. Subjective assessment of noticeability of disfigurement and associated psychological distress may be more useful in prioritizing treatment in systems with limited resources. Copyright © 2010 Lippincott Williams & Wilkins

A population-specific material model for sagittal craniosynostosis to predict surgical shape outcomes

Sagittal craniosynostosis consists of premature fusion (ossification) of the sagittal suture during infancy, resulting in head deformity and brain growth restriction. Spring-assisted cranioplasty (SAC) entails skull incisions to free the fused suture and insertion of two springs (metallic distractors) to promote cranial reshaping. Although safe and effective, SAC outcomes remain uncertain. We aimed hereby to obtain and validate a skull material model for SAC outcome prediction. Computed tomography data relative to 18 patients were processed to simulate surgical cuts and spring location. A rescaling model for age matching was created using retrospective data and validated. Design of experiments was used to assess the effect of different material property parameters on the model output. Subsequent material optimization-using retrospective clinical spring measurements-was performed for nine patients. A population-derived material model was obtained and applied to the whole population. Results showed that bone Young's modulus and relaxation modulus had the largest effect on the model predictions: the use of the population-derived material model had a negligible effect on improving the prediction of on-table opening while significantly improved the prediction of spring kinematics at follow-up. The model was validated using on-table 3D scans for nine patients: the predicted head shape approximated within 2 mm the 3D scan model in 80% of the surface points, in 8 out of 9 patients. The accuracy and reliability of the developed computational model of SAC were increased using population data: this tool is now ready for prospective clinical application

Validation of an in-silico modelling platform for outcome prediction in spring assisted posterior vault expansion

BACKGROUND: Spring-Assisted Posterior Vault Expansion has been adopted at Great Ormond Street Hospital for Children, London, UK to treat raised intracranial pressure in patients affected by syndromic craniosynostosis, a congenital calvarial anomaly which causes premature fusion of skull sutures. This procedure aims at normalising head shape and augmenting intracranial volume by means of metallic springs which expand the back portion of the skull. The aim of this study is to create and validate a 3D numerical model able to predict the outcome of spring cranioplasty in patients affected by syndromic craniosynostosis, suitable for clinical adoption for preoperative surgical planning. METHODS: Retrospective spring expansion measurements retrieved from x-ray images of 50 patients were used to tune the skull viscoelastic properties for syndromic cases. Pre-operative computed tomography (CT) data relative to 14 patients were processed to extract patient-specific skull shape, replicate surgical cuts and simulate spring insertion. For each patient, the predicted finite element post-operative skull shape model was compared with the respective post-operative 3D CT data. FINDINGS: The comparison of the sagittal and transverse cross-sections of the simulated end-of-expansion calvaria and the post-operative skull shapes extracted from CT images showed a good shape matching for the whole population. The finite element model compared well in terms of post-operative intracranial volume prediction (R2 = 0.92, p < 0.0001). INTERPRETATION: These preliminary results show that Finite Element Modelling has great potential for outcome prediction of spring assisted posterior vault expansion. Further optimisation will make it suitable for clinical deployment