The significance of rotation in fracture-separation of the articular pillar of a lower cervical vertebra: A clinical and cadaveric study

We report 13 fracture-separations of an articular pillar at the lower cervical spine in 12 patients. There were 9 men and 3 women with a mean age at injury of 32 years, with involvement of C4, C5 and C6 vertebrae. Neurological symptoms were present in 9 patients, 2 were classified as ASIA A and 7 as ASIA D. The average magnitude of rotation of the articular pillar was 24° (10°-36°). 4 patients with neurologic deficit and a rotated articular pillar of more than 25° were operated on, while 8 patients, 3 of which had a rotation of more than 25°, had closed treatment. Patients were followed from 8 months to 15 years (mean 9 years). Patients who had closed treatment and/or with a rotated fractured articular pillar of more than 25° had less satisfactory results. This observation was affirmed by cadaveric studies which showed that rotation of more than 25° is an additional factor of instability in a fractured articular pillar.