Five Reasons Why Some Herniated Intervertebral Discs are Painless.

Herniated intervertebral discs (HIVDs) can cause lower back pain and leg pain, but not all cases are painful. We suggest five potential reasons for painless HIVDs. First, when inflammation resolves or is insufficient, pain may not occur. Second, rare cases exhibit motor or sensory deficits without pain, suggesting a mechanical rather than inflammatory component. Third, changes in gene expression within the dorsal root ganglia may prevent persistent inflammation and pain. Fourth, reorganization of neural circuits in the spinal dorsal horn can reduce nociceptive signals and lead to painlessness. Fifth, effective pain coping strategies and higher pain tolerance may mask any discomfort. Understanding these factors can improve clinicians' knowledge and aid in pain management.