This is an example of arachnoiditis, or adherence of the lumbar nerve roots to the thecal sac. There are two primary etiologies of spinal arachnoiditis: infection and inflammation. Some patients have a history of spinal meningitis, others a history of prior spine surgery, intrathecal drug delivery or intrathecal hemorrhage. Patients can experience leg pain, sensory changes or motor weakness. When assessing for arachnoiditis, look for I) clumping or distortion of the lumbar nerve roots, 2) nerve roots adherent to the thecal sac resulting in an “empty thecal sac sign”, 3) nerve roots and thecal sac clumped together centrally within the spinal canal. Presently, there is no good treatment for arachnoiditis. Intrathecal drug pumps may help with pain.