Vertical Craniocervical Instability
Vertical instability craniocervical instability (CCI) is when the craniocervical junction overextends upwards and downwards.
How to & Challenges in Investigating Vertical Craniocervical Instability (CCI)
A complete and through assessment of vertical CCI appears to be a challenge for patients as it appears that the majority of physicians rely on Lateral XRays, supine MRI Brain or Cervical Spine with craniocervical junction imaging to rule out basic structural issues (like a fracture or cervical stenosis) but often the Radiologist will overlook vertical CCI because the physician has not requested vertical CCI to be ruled out; or radiologists may just make an opinion on a quick look vs. measuring the craniocervical junction.
Another current issue with diagnostic imaging to rule out craniocervical instability is dynamic imaging (flexion, extension, rotation) is not completed or the Radiologist doesn’t do a thorough report on the craniocervical junction in all positions. There have been cases whereby a person’s imaging can be normal or borderline ( and “borderline” is missed because the 1st radiologist “eyed” their opinion instead of measuring) but their craniocervical junction measurements are abnormal in either flexion, extension or both. For example, when the head moves in flexion to neutral, then to extension, the measurements of the craniocervical junction can be very different. In some cases, BDI and BAI (Harris measurements) and CXA measurement might be mildly abnormal in neutral and extension; but very abnormal in flexion. Basically put, assuming a fracture and Chiari malformation has been ruled out, the abnormality / instability depends on where the soft tissue damage is… and no 2 people are alike.