Mercedes Benz Pattern Craniosynostosis

Background: The complex craniosynostoses, which include all nonsyndromic multiple sutural fusions, represent a small fraction of patients presenting with craniosynostosis. Among these are a trisutural fusion, dubbed the "Mercedes Benz pattern," involving the sagittal and both lambdoid sutures. The purpose of this report is to review the authors' series of this unusual form of craniosynostosis, to identify associated anomalies, and to assess treatment outcomes. Methods: The authors conduced a retrospective clinical outcome assessment of all patients presenting with Mercedes Benz pattern craniosynostosis. Growth was assessed by direct anthropologic measurements, and significance was assessed by the t test. Results: Over a 17-year period, 11 of 802 patients presenting with craniosynostosis were identified with Mercedes Benz pattern synostosis (1.4 percent). Three patients had additional sutural involvement and two had identifiable genetic syndromes. Seven of 11 (64 percent) had cerebellar tonsillar herniation on preoperative imaging, and four symptomatic patients (36 percent) have required Chiari decompressions. Three patients have required more than one remodeling procedure. Serial postoperative anthropologic measurements identified progressive brachycephaly, with diminished growth in both head circumference and skull length (mean follow-up, 3.75 years). Cognitive function was grossly normal, except for one syndromic patient. Conclusions: Despite fusion of the sagittal suture, the surgical treatment for Mercedes Benz pattern craniosynostosis should include skull lengthening, not reduction. The authors' findings for diminished postoperative growth suggest that an overcorrection be considered. Fourth or fifth sutural involvement correlated with additional corrections. Given the observed high incidence for symptomatic cerebellar tonsillar herniation, routine magnetic resonance evaluations are recommended for affected individuals.