OSSIFICATION OF THE POSTERIOR LONGITUDINAL LIGAMENT IN EVOLUTION IN 12 PATIENTS

Ossification of the posterior longitudinal ligament (OPLL) in evolutio n (OEV), an early form of OPLL, was newly discovered in 12 of 43 (28%) patients who had OPLL and underwent operations from 1989-1992. Magnet ic resonance imaging and CT studies of OEV patients who were younger, in their mid-forties, and had less severe spastic myeloradiculopathy, showed hypertrophied posterior longitudinal ligaments containing punct ate ossification at disc spaces and continuous endplates, with occasio nal extension behind vertebral bodies. However, both location and neur oradiologic appearance allowed OEV to be confused readily with disc or spondylotic disease. Only heightened awareness of the clinical and ra diographic findings of OEV allowed the correct diagnosis. The appropri ately extended anterior discectomies or corpectomies with fusions cont ributed to better outcomes.