Revalidating Pfirrmann's Magnetic Resonance Image-Based Grading of Lumbar Nerve Root Compromise by Calculating Reliability among Orthopaedic Residents.

Background: Intervertebral disc herniations lead to subsequent compromise of the nerve root. The root can either have a mere contact with the disc material or be pushed aside or compressed. This was earlier graded by Pfirrmann and colleagues.