Dynamic motion analysis of normal and unstable cervical spines using cineradiography. An in vivo study

Cervical motion patterns were analyzed in a normal population and in patients with cervical instability by using cineradiography.

To determine normal and pathologic motion patterns in the cervical spine through an in vivo continuous motion analysis.

Cineradiographic techniques have been used in a limited number of studies to quantify spinal motion. There is a paucity of information regarding dynamic motion patterns in normal and pathologic cervical spines.

Ten healthy subjects and 12 patients with unstable cervical spines (C1-C2 subluxation caused by rheumatoid arthritis, n = 10; instability below C2, n = 2) were studied. Cervical motion during flexion from the maximum extension position was recorded using cineradiography. Cervical segmental motions (C1-C2 to C5-C6) were continuously measured through quantifying cineradiographic images projected on a digitizer.

Normal cervical spines showed a well-regulated stepwise motion pattern that initiated at C1-C2 and transmitted to the lower segments with time lags. Pathologic spines showed a different order of onset of segmental motion. In patients with rheumatoid arthritis who had atlantoaxial subluxation, C1-C2 motion initiated significantly earlier than C2-C3 motion. In patients with segmental instability below C2, motion in the unstable segments preceded that in the upper intact segments.

Different motion patterns were observed between normal and pathologic cervical spines. Cineradiographic motion analysis is a valuable adjunctive technique, especially in diagnosis or evaluation of conditions that cannot be identified through conventional radiographic examination.