Decompression for Chiari type I-malformation (with or without syringomyelia) by extreme lateral foramen magnum opening and expansile duraplasty with arachnoid preservation: comparison with other technical modalities (Literature review).

Posterior craniocervical decompression is the procedure most currently used for treating Chiari I malformation (alone or in association with syringomyelia in the absence of hydrocephalus). We reviewed the various technical modalities reported in the literature. We present a personal series of 44 patients harboring Chiari type I malformation (CM-I) operated with a suboccipital craniectomy and a C1 (or C1/C2) laminectomy, plus an extreme lateral Foramen Magnum opening, a "Y" shaped dural incision with preservation of the arachnoid membrane, and an expansile duraplasty employing autogenous periosteum. Outcomes were analyzed with follow-up ranging from 1 to 10 years (4 years on average). The presented technique was compared with the other surgical modalities reported in the literature. This comparative study shows that this type of craniocervical decompression achieved the best results with minimal complications and side-effects. Syringomyelia associated with CM-I must be treated by craniocervical decompression alone. Shunting no longer appears to be an appropriate method of treatment for syringomyelia.