Inflammatory disc disease or Modic 1 disc disease is a radiological entity first described by Modic in 1988 and corresponds to an inflammatory signal on MRI defined by the presence of a T2-weighted hypersignal and a T1-weighted hyposignal of the vertebral endplates adjacent to a pathological disc.

The presence of these radiological abnormalities are significantly associated with chronic low back pain, the therapeutic management of which may include lumbar rehabilitation, rigid corset, spinal infiltrations and surgical treatment. Corticosteroid infiltration of the pathological intervertebral disc (intradiscal infiltration) has been evaluated in low back pain due to Modic 1 disc disease with short-term efficacy. The clinical response to this infiltration is not always optimal and to date in the literature, no predictive factor of response has been identified.

There are several hypotheses to explain this phenomenon: mechanical, genetic, infectious or inflammatory. One of the mechanical hypotheses would be the presence of an instability of the spinal segment (hypermobility of the spinal segment) and disorders of the sagittal statics of the spine with angles of thoracic kyphosis and lumbar lordosis weak and a weak sacral slope supporting a hyperpressure passing by the discs and the genesis of discopathy.

In this work, the investigators will evaluate the different parameters of the spinal statics in the sagittal plane and in the frontal plane (sacral slope, pelvic version, Roussouly classification, cobb angle...) by EOS imaging as well as the parameters of the Modic 1 anomaly on lumbar MRI (spinal stage, Pfirmann classification, laterality of the inflammatory signal) in a population of patients who received intradiscal corticosteroid infiltration for low back pain in the context of Modic 1 disc disease.

The analysis of the different radiological parameters could enrich the investigator's understanding of the pathophysiology and evaluate radiological factors predictive of the effectiveness of intradiscal infiltration in this population. This could allow us to adapt the management of low back pain patients with Modic 1 disc disease.

Inclusion Criteria:

• Patient whose age ≥ 18 years
• French speaking patient
• Patient hospitalized in the rheumatology department of GHPSJ between 01/01/2014 and 31/12/2020 for MODIC 1
• Patients who received as part of their management an intra-disc infiltration with hydrocortancyl.

Exclusion Criteria:

• Patient under guardianship or curators
• Patient deprived of liberty
• Patient under court protection
• Patient objecting to the use of his data for this research
• Patient having benefited from another infiltration between the intradiscal infiltration and the collection of efficacy data at 3 months.

Patient hospitalized in the rheumatology department of GHPSJ between 01/01/2014 and 31/12/2020 for MODIC 1