Follow-up study to investigate symmetry and stability of cranioplasty in craniosynostosis - Introduction of new pathology-specific parameters and a comparison to the norm population.

Purpose: Cranioplasty and modulation of frontoorbital advancement (FOA) in children with craniosynostosis aims to achieve an attractive aesthetic and functional rehabilitation of the forehead area, comparable to that in unaffected children. Based on a three-dimensional surface scan, a cephalometric data evaluation with new parameters for the quantification of physiological and pathological cranial morphologies, and objective evaluation of postoperative follow-up in comparison to an age-equivalent standard population, were performed.

Materials And Methods: In a prospective study, 80 children were operated on with non-syndromic craniosynostosis (trigonocephalus, n = 30; plagiocephalus, n = 10; scaphocephalus, n = 38; brachycephalus, n = 2) and pre- and 3, 6, 12, 18 and 30 months postoperative three-dimensional surface scans were obtained (3DShape, Erlangen, Germany) and morphometrically measured (Onyx Ceph, Image Instruments, Chemnitz, Germany). In addition, 49 healthy children who were not operated on were measured at equivalent ages (n = 25 [6 months]; n = 20 [9 months]; n = 4 [12 months]).

Results: All patient groups showed stable long-term results with regard to shaping of the forehead. Cranioplasty in patients with scaphocephalus resulted in a significant widening of the anterior (73.9 ± 3.5 mm; p < 0.001) and posterior (132.2 ± 5.2 mm; p < 0.001) cranial width, with no significant difference from the norm population 1 year after surgery (p = 0.6597). As parameters for the correction of trigonocephaly, the frontal angle showed significant improvement (145.9 ± 3.7°; p < 0.001). While the parietal angle 12 months after surgery showed similar values as the norm population, the frontal angle was about 10° smaller than in healthy children (p = 0.0055), despite a clinically inconspicuous physiognomy. As part of the correction of plagiocephaly, the patients tended to relapse in the postoperative course, although there was no statistically significant difference in the frontal angle compared to that in the norm population (153.3 ± 3.9°; p = 0.06). While 6 months after surgery all patients showed a normal cranial volume development compared to healthy children of the same age, the volumes of brachycephalic patients remained below the norm (1244.2 ± 153.2 cm; p = 0.0244). Overall, the analysis of the norm population showed a growing dispersion of measurement values with increasing age, which was observed to be more concentrated in the operated cranial morphologies.

Conclusion: The determination of new pathology-specific morphometric parameters on the three-dimensional surface scan enables an objective quantification of physiological and pathological cranial morphologies of children. A comparison of operated children with a healthy, age-appropriate comparison group showed that preoperative and statistically significant deviations of the new measuring parameters in long-term follow-up could be normalized through surgical intervention, although this does not apply without limitations to children with coronary suture synostosis.