lumbar disc herniation
• Epidemiology
◦ 95% involve L4/5 or L5/S1 levels
L5/S1 most common level
◦ peak incidence is 4th and 5th decades
◦ only ~5% become symptomatic
◦ 3:1 male:female ratio
• Pathoanatomy
◦ recurrent torsional strain leads to tears of outer annulus which leads to herniation of nucleus pulposis
• Prognosis
◦ 90% of patients will have improvement of symptoms within 3 months with nonoperative care.
◦ size of herniation decreases over time (reabsorbed)
sequestered disc herniations show the greatest degree of spontaneous reabsorption
macrophage phagocytosis is mechanism of reabsorption