The anatomical basis of sciatica secondary to herniated lumbar disc: a review

The purpose of this manuscript is to illustrate the key anatomical and biomechanical elements involved in the etiopathogenesis of sciatica, and to demonstrate how periradicular fibrosis contributes to the pathophysiology of recurrent post-operative sciatica. History, etiology, anatomy and diagnosis of herniated inter-vertebral disc are reviewed. The straight leg raising exam is a well accepted test in the diagnosis of lumbar disc herniation. In the post-operative patients, the results of the straight leg raising test are affected by the presence of scar and fibrosis around the lumbar root(s) involved. The mechanisms by which perineural fibrosis and adhesions change and compromise the neural dynamics and causes symptoms to recur in the post-operative patient are discussed. Due to its dramatic clinical relevance, prevention of periradicular fibrosis has high priority in the surgical management of herniated lumbar disc. Such a goal should be obtained by using a combination of appropriate indication to surgery, impeccable operative technique and the use of an effective anti-fibrotic agent.