Optimal diagnosing and interventional treatment of the posterior ligamentous complex inflammatory syndrome.

Introduction: The previously described posterior ligamentous complex inflammatory syndrome can result in chronic axial low back pain. This condition can be identified through MRI findings that demonstrate inflammatory changes in the compartments of the posterior ligamentous complex region, with the space of Okada serving as a connection between them. However, an effective interventional treatment for this syndrome has not yet been proposed. Case: We present the case of a patient suffering from persistent axial low back pain who did not respond to medication or physical therapy. A SPECT scan revealed significant radiotracer uptake in the bilateral L4-L5 facet joints and the L4-L5 interspinous ligament. Given that bilateral L3-L4 diagnostic medial branch blocks yielded negative results, posterior ligamentous complex inflammatory syndrome was suspected. Injection of contrast dye into the L4-L5 interspinous adventitial bursa demonstrated the spread of contrast material from the injection site to the space of Okada and the bilateral L4-L5 facet joints. Subsequent steroid injection provided the patient with over 80 % pain relief at the five-week follow-up. Conclusion: Patients experiencing axial low back pain, particularly those with negative diagnostic medial branch blocks, should consider undergoing a SPECT scan. This recommendation is particularly relevant in cases involving Baastrup disease or pars defects, as these conditions are often associated with the presence of the space of Okada, which is crucial for the development of PLCIS. If this diagnosis is confirmed through imaging, a steroid injection into the adventitial interspinous bursa may offer an effective treatment for PLCIS by facilitating medication distribution throughout the compartments of the posterior ligamentous complex region.