Fig. 3

Magnetic resonance imaging (MRI) and intra-procedural fluoroscopy images of a 65-year-old man (case 1). (a, b) Sagittal and axial lumbar MRI T2-weighted images reveal spondylolisthesis of the fourth lumbar spine and uncontained lumbar disc herniation characterized by upward migration of the nucleus pulposus due to fibrous annulus rupture at the fourth to fifth lumbar intervertebral discs. The displaced nucleus pulposus is situated in the left paracentral direction, causing compression of the dural sac and the left fourth lumbar nerve root. (c, d) During percutaneous lumbar nucleoplasty performed with the patient under local anesthesia, fluoroscopy demonstrates successful access as the radiofrequency (RF) probe navigates through the torn opening of the fibrous annulus and follows the upwardly displaced disc fragment deep within the spinal canal. RF plasma was administered from this location to the interior of the disc for approximately 10 min