PAN 1.3 Chiari malformation in complex craniosynostosis and syringomyelia: epidemiology, management and surgical attitude

Abstract

Introduction: Chiari malformation (CM) secondary to complex craniosynostosis is one of the most debated subjects in the discussion about surgical management in the facio- craniosynostotic patients. Premature fusion of cranial vault and cranial base sutures, congenital anomalies of the cerebellum, venous hypertension and hydrocephalus responsible of raised intracranial pressure are all the parameters to consider. The impact of foramen magnum decompression and posterior expansion/distraction is analyzed. Methods: This is a monocentric retrospective study including 182 patients with complex craniosynostosis treated between 2001 and 2016. Crouzon (88 patients, 52M/36F), Aperts (33 patients,18M/15F) and Pfeiffer (30 patients 16M/14F), 31 non-syndromic with combined bilambdoid and sagittal synostosis were included. 30/182 were submitted to foramen magnum decompression as first or second procedure, in 14/30 associated to posterior expansion; in 41/180 patients a posterior expansion/distraction has been realised without Chiari decompression. The impact of genetic anomalies, syringomyelia, sleep study results, control of raised ICP has been evaluated. Results: 42 patients presented Chiari type I malformation (19 patients with Crouzon, 23 with Pfeiffer, none in Aperts). Among them, syringomyelia was present in 25 children with Crouzon or Pfeiffer but none in Aperts. The mean age of syringomyelia diagnosis was 5.5 years (range, 10 months to 16 years). FM decompression decreased the number of central and obstructive sleep apnea. Neurological symptoms were relieved but syringomyelia images stayed unchanged. In the group of patients submitted to a simple posterior expansion, in 3% of cases a FM decompression became necessary for a CM aggravation with SOAS apparition Conclusions: FM decompression should be considered the main treatment for Chiari malformation to prevent late syringomyelia and central sleep apneas, in Crouzon and Pfeiffer. It can be associated with posterior vault expansion in the same time if intracranial pressure is present, but this study suggests that insufficient treatment of Chiari will lead to syringomyelia.