Surgical Management of Chiari Malformation Type I and Instability of the Craniocervical Junction Based on Its Pathogenesis and Classification.

We investigated the mechanism underlying Chiari malformation type I (CM-I) and classified it according to the morphometric analyses of posterior cranial fossa (PCF) and craniocervical junction (CCJ). Three independent subtypes of CM-I were confirmed (CM-I types A, B, and C) for 484 cases and 150 normal volunteers by multiple analyses. CM-I type A had normal volume of PCF (VPCF) and occipital bone size.

Safety analysis and complications of condylar screws in a single-surgeon series of 250 occipitocervical fusions.

Objective: Condylar screw fixation is a rescue technique and an alternative to the conventional configuration of occipitocervical fusion. Condylar screws are utilized when previous surgical bone removal along the supraocciput has occurred which makes anchoring of a traditional barplate technically difficult or impossible. However, the challenging dissection of C0-1 necessary for condylar screw fixation and the concerns about possible complications have, thus far, prevented the acquisition of large surgical series utilizing occipital condylar screws.

Electromyographic assessment of condylar screw placement during occipitocervical fusion.

Objective: This is a retrospective study of a series of occipitocervical fusion procedures with condylar screw fixation in which the authors investigated the utility of electromyography (EMG, free-running and triggered) as a reliable tool in assessing the positioning of condylar screws. This series consisted of 197 patients between 15 and 60 years of age who presented with craniocervical instability, and who were treated between October 2014 and December 2017.

Methods: Intraoperative free-running EMG was observed at the placement of condylar screws, as well as at realigning of the spine.

Diagnosis and treatment of Chiari malformation and syringomyelia in adults: international consensus document.

Background: Syringomyelia and Chiari malformation are classified as rare diseases on Orphanet, but international guidelines on diagnostic criteria and case definition are missing.

Aim Of The Study: to reach a consensus among international experts on controversial issues in diagnosis and treatment of Chiari 1 malformation and syringomyelia in adults.

Methods: A multidisciplinary panel of the Chiari and Syringomyelia Consortium (4 neurosurgeons, 2 neurologists, 1 neuroradiologist, 1 pediatric neurologist) appointed an international Jury of experts to elaborate a consensus document.