Effectiveness of modified dural incision to preserve the patency of the occipital sinus in foramen magnum decompression for a patient with Chiari malformation type I

Background: Foramen magnum decompression (FMD) has been acknowledged as a standard surgical procedure for symptomatic patients with Chiari malformation type I (CM-I). However, even if dural incision is necessary during FMD, the procedure of cutting off the occipital sinus has not been regarded as a safe option.