The relevance of magnetic resonance imaging (MRI) findings such as facet joint (FJ) effusion and edema in low back pain (LBP) is still unknown. Therefore, we prospectively evaluated the presence of these MRI findings in the lumbar spine (Th12-S1) and their association with pain evoked by manual segmental FJ provocation tests (spinal percussion, springing, and segmental rotation tests) in 75 subjects with current LBP (≥30 days in the past 3 months) compared with 75 sex- and age-matched control subjects. FJs were considered painful, if ≥ 1 provocation test triggered LBP. FJs were classified as true positives, if the same FJ was painful and showed effusion and/or edema. FJs with effusion and/or edema and painful FJs were present significantly more frequently in subjects with LBP, but these conditions were also common in control subjects (27% vs 21% and 50% vs 12%, respectively). Effusion and/or edema were present in 65 subjects with LBP (87%) and in 56 control subjects (75%, not significant); painful FJs were present in 68 (91%) and 29 (39%) (P<0.01) LBP and control subjects, respectively. True-positive findings occurred in 16% of LBP FJs and in 2% of control FJs (P<0.01); 46 LBP subjects (61%) and 9 control subjects (12%, P<0.01) had true-positive findings. Pain on provocation and FJ effusion and/or edema were significantly correlated only in patients with LBP. In conclusion, only true-positive findings (ie, concurrent effusion and/or edema and positive provocation test results in the same FJ) discriminate well enough between control subjects and subjects with current LBP, whereas neither effusion and/or edema nor FJ provocations tests alone are suitable to detect suspected FJ arthropathy.

This article presents a case of unsuccessful pharmaceutical and invasive pain treatment for 6 years without any adequate diagnostics in a female suffering from unilateral thoracic radiculopathy (Th8, right) leading to severe disability and unemployment. The origin was an undetected Tarlov cyst. After resection of the cyst the pain and other complaints disappeared (follow up: 8 months) without need for further pain medication. This case underlines the necessity of adequate diagnostics ahead of long-term pain treatment. Thoracic Tarlov cysts are very uncommon but should be included in the differential diagnosis because curative treatment may be possible.

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