Craniosynostosis and Chiari I Malformation Managed With Middle 1/3 Calvarial Vault Expansion

Multisutural syndromic craniosynostosis is strongly associated with secondary Chiari malformation. Although less commonly described, single suture synostosis can also be associated with secondary Chiari malformation due to craniocephalic disproportion. These children have traditionally been treated with posterior vault expansion; however, in patients with sagittal synostosis, increasing only the posterior vault volume can worsen the scaphocephalic deformity. In addition, treating a Chiari malformation with a decompression without addressing the craniocephalic disproportion during a period of continued skull growth can be insufficient for the future neurodevelopment of the patient. Our study describes 3 cases of craniosynostosis (2 isolated sagittal, 1 sagittal with partial lambdoid-upper 1/3 of the suture) with concurrent Chiari malformation that were successfully treated with middle 1/3 vault expansion using the Pi-Hung Span procedure. As this procedure avoids a craniotomy over the torcular and transverse sinus, this method also decreases the risk of sinus injury during surgery. All 3 patients, with 6 to 18 months of follow-up, experienced both symptomatic improvement and radiographic improvement of tonsillar herniation. Supratentorial vault expansion should be considered as a viable surgical treatment for children with Chiari malformation secondary to craniosynostosis to prevent worsening scaphocephaly and to provide a complete reconstruction for the overall anatomic disproportion in the setting of continued skull growth.