The incidence of ossification of the posterior longitudinal ligament (OPLL) among North Americans with cervical myelopathy has recently increased from 2% to 25%, a figure that approaches the 27% figure noted in Japan. This increase reflects improved magnetic resonance imaging, computed tomography (CT), and myelo-CT recognition of segmental, mixed, continuous, and other OPLL. Definition of a new, earlier form of OPLL, OPLL in evolution, and differentiation of this form of OPLL from multilevel disc disease, have also increased the frequency of OPLL. Postoperative outcomes following anterior (anterior corpectomy and fusion, anterior diskectomy and fusion), or posterior (laminectomy, laminoplasty) cervical surgery from different OPLL series were compared using Ranawat's Neurological Classes and Grades. Superior surgical results could not be attributed to either anterior or posterior surgical OPLL techniques. Somatosensory evoked potential monitoring, awake intubation, and awake positioning appeared to contribute to the elimination of postoperative quadriplegia and radicular injury in our OPLL study.
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