(Arnold) Chiari malformation: Intraoperative ultrasound shows the abnormal anatomy in motion. скачать в хорошем качестве

(Arnold) Chiari malformation: Intraoperative ultrasound shows the abnormal anatomy in motion.

In this child with Chari malformation, we can see the abnormally descended tonsils of the cerebellum in the spinal canal. The medulla, the cervical cord, and the tonsils crowd the narrow space at the opening of the base of the skull called the foramen magnum. You can see the tonsils pulsating and pushing down with each heartbeat. If you watch carefully, you can also see the streams of the cerebrospinal fluid flowing down this crowded channel. If left untreated, the perturbation in the flow eventually causes the fluid to get into the spinal cord and cause neurological symptoms and signs. The fluid cavity that forms in the cord is called a syrinx. The fluid dissects (rips) through the densely packed fibers and cells of the spinal cord to cause numbness and weakness. The pattern of numbness is classically termed a 'dissociated and suspended sensory loss' that affects the ability to sense pain and temperature but spares fine touch. This child did not have a syrinx but had a bit of high signal on T2 weighted MRI, and that is seen as an area of reduced echo in the cord in the ultrasound imaging. Perhaps, a bit of fluid has accumulated in the cord. She only had oscillopsia (the illusion of objects shaking) as the symptom and nystagmus (eyes shaking on gazing to the sides) as the neurological sign. Removing a small area of the base of the skull above the foramen magnum (a 2.5 x 2 cm square area of the bone) and expanding the dura by sewing a piece of pericranial tissue expands space there and improves the flow of fluid, and prevents further damage. The next day after the surgery, she said that objects no longer shake when she looks down even though we could still observe nystagmus in her eyes.