Ossification of the ligament flavum.

A total of 82 patients who underwent spinal computed tomographic scan, in an 8-month period at the King Khalid University Hospital, Riyadh, Saudi Arabia, were analyzed for age, sex, the presence/absence, site, and type of ossification of the ligamentum flavum (OLF) as well as associated diseases. The OLF was radiographically present (bilaterally or unilaterally) as linear (74.5%) or nodular types (25.5%). The linear type was especially seen at the inner aspects of the ligamentum flavum. OLF was present in 35.4% of patients, and was seen at single and multiple levels in 51% and 41% of them, respectively. OLF was identified in a total of 47 levels in the study group and was associated with other disease in the spine in 38 (81%) of these levels. In none of the patients was OLF the cause of myelopathy. The incidence of OLF and its pathogenesis and significance are discussed. This paper is the first report of OLF from the Middle East. OLF in this part of the world is usually asymptomatic.