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Spine
intermediate
X-Type

Cervical Instability - ADI, SAC, and Rheumatoid Cervical Spine

Cervical Instability

A 58-year-old woman with a 20-year history of rheumatoid arthritis presents with progressive neck pain, occipital headaches, and bilateral hand numbness. She is on methotrexate and a biologic agent. Lateral cervical radiographs in flexion show anterior atlantoaxial subluxation. The atlantodental interval (ADI) measures 8mm in flexion, and the posterior atlantodental interval (PADI) is 12mm. MRI demonstrates pannus formation posterior to the odontoid with mild cord compression but no T2 signal change. Regarding the radiographic assessment of atlantoaxial instability:

Mark each as TRUE or FALSE

A

The ATLANTODENTAL INTERVAL (ADI) is measured from the posterior aspect of the anterior arch of C1 to...

B

The SPACE AVAILABLE FOR CORD (SAC) or POSTERIOR ATLANTODENTAL INTERVAL (PADI) is measured from the p...

C

The ADI in adults is normally less than 10mm and is a more reliable predictor of neurological outcom...

D

The TRANSVERSE LIGAMENT is the PRIMARY restraint to anterior atlantoaxial translation (resists 65% o...

E

RHEUMATOID CERVICAL INSTABILITY occurs in three patterns: ATLANTOAXIAL SUBLUXATION (most common, 65%...

Answer the questions to see explanations

Click T (True) or F (False) for each option