Spontaneous Regression of Posterior Ring Apophysis Separation in Lumbar Spine

The pathogenesis of spinal posterior ring apophysis separation (PRAS) remains controversial, and spontaneous regression of PRAS has not been established previously. This is a case report about a 33-year-old man with a PRAS of the posterior superior end plate of S1 who presented with spontaneous low back pain followed by right leg pain. The patient was managed conservatively. A control lumbar spinal computed tomography scan performed 3 years later revealed complete spontaneous regression of the detached bony fragment.