Symptomatic ossification of the posterior longitudinal ligament of the lumbar spine. Case report.

The authors report a case of focal ossification of the posterior longitudinal ligament (OPLL) behind the L-3 vertebral body. This is relatively rare among previously reported cases in the literature. Magnetic resonance (MR) imaging revealed that the ossifying portion of the PLL was impinging on the left L-3 nerve root. Contrast enhancing hypertrophic PLL was also demonstrated around the ossification and along the lumbosacral PLL. Via a laminectomy and wide excision of the PLL the lesion was removed. Pathological examination revealed a nodule composed of fibrous cartilage, lamina bone, and mature fat marrow. Enchondral ossification could be identified under a microscope. The authors believe that preoperative MR imaging evaluation is important for the detection of the relationship between an OPLL and the neural structure. Excision of the symptomatic OPLL should be performed when needed to obtain adequate nerve root decompression.