Fifteen patients with atlanto-axial instability (secondary to os
odontoideum in three, nonunion of an odontoid fracture in seven, acute
odontoid fracture in three, and rheumatoid arthirtis in two) were treated
by wedge compression arthrodesis of the atlanto-axial joint. One patient
died at home eight weeks after fusion with the cause of death never
established. Of the two patients with rheumatoid arthritis (ankylosing
spondylitis), one had a non-union and in the other the posterior arch of
the atlas fractured and the fusion had to be extended up to the occiput and
down to the third cervical vertebra. The procedure is rarely indicated in
patients with long-standing rheumatoid arthritis or severe osteopenia.