Rehydration of a degenerated disc on MRI synchronized with transition of Modic changes following stand-alone XLIF.

Lumbar intervertebral disc degeneration (LDD) is known to be associated with low back pain (LBP) and leads to degenerative lumbar disease. LDD is considered to be irreversible, and no truly effective treatment that suppresses LDD or regenerates the degenerated disc has been established thus far. Here, we report the case of a 42-year-old woman with a 10-year history of persistent LBP. Magnetic resonance imaging (MRI) demonstrated degenerative changes (Pfirrmann classification: grade IV) in the L4-5 intervertebral disc with type I and III mixed Modic changes adjacent to the disc. Conservative treatments were not effective, so we opted for stand-alone extreme lateral interbody fusion (XLIF). One year after the operation, the LBP had almost disappeared. Follow-up MRI revealed transition of the Modic changes from type I to type III. In addition, rehydration of the degenerated disc behind the XLIF cage was evident (Pfirrmann classification changed from grade IV to grade II). To our knowledge, this is the first report of a change in LDD. Several factors are likely responsible for the regenerative response, including curettage of the hyaline cartilaginous endplates and auto-iliac cancellous bone grafting, which were considered to have affected nucleus pulposus cells in the residual disc.