Lumbar disc herniation Epidemiology

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