Prognostic Factors in Zygapophyseal Osteoarthritis Infiltration: a Prospective Cohort Study

Inclusion criteria The following are inclusion criteria for participants: * Older than 18 years; * Fluent or native Portuguese language speaker; * Continuous or intermittent low back pain for at least three months; * Low back pain with or without irradiation to the gluteal region indicating facet syndrome (pain is aggravated by spine extension or bending toward the affected side; pain is exacerbated by prolonged sitting or walking up steps, as well as retaining one position for a prolonged time); * Failure of traditional treatment includes, but is not limited to, physical or drug therapy; * Understand the purpose of the study; * Voluntarily provide a free and informed consent form, by themselves or through their partners, and complete the questionnaires, before undergoing infiltration, over the telephone or online during the follow-up. Exclusion criteria The following are exclusion criteria for participants: * Younger than 18 years old, * Symptomatic lumbar spinal stenosis with claudication or radiculopathy; * Evidence of radiculopathy; * Active rheumatologic diseases; * Congenital or acquired deformities of the lumbar spine; * Fracture or sequel of lumbar spine fracture of traumatic, pathological or osteoporotic origin; * Surgical manipulation of the lumbar spine; * MRI scans of limited quality and incomplete sequences; * Treated with systemic steroids less than one month before the IFI; * Treated with IFI with steroids within the last six months; * Diagnosed with uncontrolled diabetes mellitus; * History of allergy to anesthetics or adverse reaction to steroids; * Pregnant women or women who breastfed; * Who could not be contacted over the phone during follow-up.