Rheumatoid Arthritis – C-Spine

Approach to the Rheumatoid C-Spine

In Summary – Need to think of three things: vertical migration, atlantoaxial, and subaxial instability

– AADI on X-ray of greater than 3 mm is abnormal. 7 mm signifies complete transverse ligament rupture. 10 mm signifies complete transverse ligament and alar ligament insufficiency
– PADI on X-ray of 14 mm or less warrants MRI investigation. PADI on MRI of 13 mm, cervicomedullary angle of 135 or less, and cord diameter of less than 6 warrants fusion.
– Basilar invagination is bad in general, and should be fused and or decompressed if you can demonstrate cord compression.
– Subaxial canal diameter on X-ray of 14 mm or less warrants MRI. PADI on MRI of 13 mm warrants decompression and fusion if cord is being compressed.

The History:
– Look for symptoms of myelopathy: bowel/bladder, progressive weakness of L/E or U/E, incoordination, gait changes, unsteadiness
– Look for cranial nerve and upper root problems: dysphagia, dysphonia, trouble swallowing, pain in occiput

The Physical
– Often very difficult to sort out motor function because of disease in joints
– L�Hermitte�s, range of motion, pain, numbness in occiput
– neurologic assessment is often based primarily on the sensory exam because everything else is difficult to assess.
– Light touch, pinprick, proprioception and vibration
– Cranial nerve exam – particularly IX, X, VII, V

X-rays – measure the PADI, assess for VMO and subaxial instability
Get an MRI and CT particularly in upper C-spine if contemplating transarticular screws

Then, the pre-op assessment
– needs bloodwork: CBC, lytes, BUN, Crt, glucose, type and screen, INR, PTT, CXR, ECG
– needs to have rheumatologist maximize medical therapy
– needs to have preop anesthesia consult for awake intubation
– need to be prepared for particular medications
– methotrexate and other immunosuppressants: stop at least a few weeks in advance? Controversial. No good studies indicate that these should be stopped. Depending on your philosophy, the risk of an acute flare probably outweighs the risk of wound infection or healing.
– steroids: need to cover her perioperatively; 100 mg hydrocortisone before surgery, second 100 mg intraoperatively, followed by 100 mg IV q8h for 24 hours, 50 mg q8h the next day, and a single dose of 100 mg IV on the third day. For minor surgical procedures, can give them a single preoperative dose of 100 mg hydrocortisone.
– NSAIDs: need to make sure that they�re off for 5-7 days.

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