Pathologic Anatomy and Mechanisms of Nerve Root Compression

Abstract

In 1934, Mixter and Barr reported nineteen cases of rupture of the intervertebral disc with the involvement of the spinal canal, and so ushered in the “dynasty of the disc”. Their paper described compression of the spinal cord, cauda equina or exiting nerve root by the her-niated material, and included four cases with a cervical localisation, four cases in the thoracic spine, ten in the lumbar spine and lumbosacral transition, and one in the sacral region! The concept of nerve root compression by herniated disc material as a cause of low back and lower extremity pain dominated etiologic and therapeutic thinking on the subject of sciatica for several decades, and its evolution is discussed in more detail in Chap. 1. Although much about the pathogenesis of sciatica and related conditions is still unclear, it is generally accepted that simple mechanical compression of an otherwise healthy nerve root by itself does not cause radicular pain: various humoral and auto-immune inflammatory factors are also at work (see Chaps. 1 and 5).