The Lumbar Multifidus Muscles are Affected by Medial Branch Interventions for Facet Joint Syndrome: Potential Problems and Proposal of a

Low back pain is a major health problem. Like any structure of the spine and its adjacent musculature, the facet joints can be a source of pain. It has been proposed that in 15%–52 % of patients with chronic low back pain, the facet joints are involved, but isolated facet joint pain is exceedingly rare.1 This is in accordance with the proposed biomechanical pathophysiology of facet joint syndrome. In the course of degenerative disk disease, the intervertebral disk loses height; this change leads to a segmental instability with an increased loading of the facet joints and consecutive osteoarthritic changes. To compen-sate for this degenerative cascade, segmental stabilization by the lum-bar musculature is extremely important.2 Especially, the multifidus muscles seem to play a key role. With cross-sectional imaging, atrophy of the multifidus muscles in chronic low back pain can be found, and targeted exercise showed an improvement in back pain.2 The multifidus muscles as well a