RESUMEN
OBJECTIVE: To investigate the frequency of ossification of the ligamentum flavum (OLF) in the spine among the Arab population in Kuwait using magnetic resonance imaging (MRI) surveillance of the whole spine. SUBJECTS AND METHODS: A consecutive series of 102 patients with low back pain were recruited from the outpatient clinic of Mubarak Al-Kabeer Hospital, Kuwait. MRI of the whole spine in the sagittal plane was obtained in at least two sequences (T(1) and T(2)). The OLF was defined as low signal intensity thickening of the ligament in both T(1) and T(2) sequences on the posterior margin of the spinal canal, causing indentation of the theca with or without cord compression. RESULTS: Of the 102 cases, 19 (18.6%) patients had OLF. Of the 19 positive cases, 12 (63.2%) were present at a single level, and 7 (36.8%) at multiple levels. A total of 26 OLF segments were identified in the following anatomical distribution: cervical: 15 (57.7%); upper thoracic (T1-T4): 1 (3.8%); mid thoracic (T5-T8): 4 (15.4%); lower thoracic (T9-T12): 4 (15.4%), and lumbar region: 2 (7.7%). Of the 19 OLF patients, 2 (10.5%) had tandem ossification of the posterior longitudinal ligament in the cervical spine and were symptomatic. CONCLUSIONS: The frequency of OLF appears to be high among this hospital-based cohort of the Arab population. OLF should be kept in mind if a patient presents with radiculopathy, particularly in the cervical region, for which surgical intervention is contemplated.