Sinus pericranii-unusual anatomic obstacle to posterior decompression on an amniotic band sequence.

Abnormal venous drainage in patients with craniofacial anomalies is relativity uncommon. Sinus pericranii is a rare vascular malformation characterized by communication between intracranial dural sinuses and extracranial venous drainage systems. The association between sinus pericranii and amniotic band syndrome has not been described. We report on a 7-month-old girl diagnosed with amniotic band sequence who underwent posterior fossa decompression due to intracranial hypertension and Chiari malformation type I. The computed tomography and magnetic resonance identified the connection between the sagittal sinus and the scalp. During the operation, the presence of sinus pericranii was a complicating factor limiting the proper exposure because of the risk of bleeding. Patients with craniofacial anomalies and sinus pericranii present an increased risk of serious surgical complications and consequences from craniofacial surgery, especially from cranioplasty and posterior decompression. Special attention must be paid to abnormal venous drainage, and vascular imaging studies are sometimes required.