Brainstem

Brainstem Compression often occurs as a result of craniocervical instability (CCI).

Evidence
Recent peer-reviewed academic research indicates that mechanical brainstem compression can be directly responsible for dysautonomia and fatigue. When patients had their brainstem compression surgically corrected with a craniocervical fusion, their symptoms of brainstem compression resolved.

There are also anecdotal accounts of POTS and fatigue going away after a craniocervical fusion to correct the brainstem compression.

As the brainstem is central to regulating the autonomic nervous system, it is perhaps unsurprising that dysautonomia (such as POTS) can be corrected by correcting brainstem compression.

Diagnosis
Brainstem compression is diagnosed via dynamic imaging, such as flexion-extension MRIs and rotational CT scans. The most common measurements used to diagnose and quantify brainstem compression are the Clivo-Axial Angle, the Grabb-Oakes Measurement, and the Basion-Dens Interval.

Treatment
A cervical collar can be tried to see if it helps alleviate the neurological symptoms (even if only partially). However, a cervical collar is not an actual treatment for CCI. The standard treatment to correct brainstem compression is a craniocervical fusion surgery, performed by a CCI-literate neurosurgeon.