case_images: PMC8247923_01
case_images: MRI cervical spine T2-weighted sagittal image.
case_images: SNI-12-226-g001.jpg
case_images: PMC8247923_01_SNI-12-226-g001.jpg
case_images: F1
case_images: The preoperative cervical MRI T2-weighted study showed a Type I Chiari malformation and syrinx (i.e., cerebellar tonsillar herniation up to the C1 level, diffusely dilated central canal from C5 to D3, and nonenhancing hyperintensity, present in the upper cervical cord [Figure 1]).
case_images: Diagrammatic representation of the first view after dural opening during surgery. PICA: Posterior inferior cerebellar artery, CNXI: Spinal accessory nerve.
case_images: SNI-12-226-g002.jpg
case_images: PMC8247923_01_SNI-12-226-g002.jpg
case_images: F2
case_images: Further, at the level of the foramen magnum, the left XI cranial nerve was severely compressed between the left-sided herniated tonsil and posterior inferior cerebellar artery (PICA) [Figure 2].
case_images: Diagrammatic representation of view after subpial resection of the left tonsil showing CNXI running just above the PICA, PICA: Posterior inferior cerebellar artery, CNXI: Spinal accessory nerve.
case_images: SNI-12-226-g003.jpg
case_images: PMC8247923_01_SNI-12-226-g003.jpg
case_images: F3
case_images: After subpial resection of the left tonsil [Figure 3], a muscle patch was interposed between the XI cranial nerve and PICA.