In an individual with Ehlers-Danlos Syndrome (EDS) and cranio-spinal instability (CSI), cranial settling is likely to occur. In cranial settling the tissues in the neck are so weak (due to EDS) that the cervical bones are not held in place. This forces the cerebellar tonsils out of the skull into the spinal column through the small hole at the base of the skull called the foramen magnum, a phenomena called cerebellar herniation. When the cerebellar tonsils are out of place, they take up space normally allotted for the cerebral spinal fluid (CSF), the brainstem, and all the arteries and veins leading through this area to the brain. This puts pressure on the cerebellar tonsils and the brainstem, which damages both structures progressively over time.
The cerebellar tonsils are the lowest part of the cerebellum, which controls the sensory perception and motor control systems of the body. The brainstem controls the autonomic nervous system, or everything your body does without you having to thinking about it - heart rate, respiration, blood pressure control, etc. Damage to these systems is very serious, and can even be life-threatening. CSI may also allow the odontoid bone at the front of the neck to push backwards into the brainstem, causing even more damage to this structure.
In addition, due to the crowding of the cerebellar tonsils, brainstem, and cranial arteries and veins, CSF flow may be impaired. Spinal fluid continuously flows around the brain and spinal cord, bringing them essential nutrients. In an individual with cranial settling, however, there may not be enough room left at the opening of the skull for the spinal fluid to effectively flow. Impaired CSF flow can deprive the brain and spinal cord of nutrients that they need in order to function properly
Symptoms: Moderate to severe headache and neck pain, dizziness, lightheadedness, vertigo, disequilibrium, palpitations, difficulty swallowing, visual disturbances, ringing in the ears, palpitations, dysautonomia, sleep apnea, chronic fatigue, painful tingling of the hands and feet, muscle weakness, scoliosis, and impaired fine motor skills.
Diagnosis: Cranial settling is normally NOT visible on a conventional horizontal MRI, X-ray, ect. It is normally only visible when the patient is upright, and even then may be difficult to identify for non-specialists. MRI's may be accompanied by craniocervical traction to confirm the diagnosis. If the patient's symptoms are worsened OR improved during traction, refer the patient to a CSI specialist such as The Metropolitan Neurosurgery Group (in the links section).