Scar tissue can occur within the spine secondary to trauma, inflammation, infection, and surgery.  Another term for scar tissue is fibrosis. Fibrosis can occur within many different regions of the spine such as around the spinal joints (facets), within muscles, between the spinal membranes (dura), within the epidural space of the spinal canal and essentially between any two adjacent dissimilar tissues.  The most common location is within the epidural space.  This is the space in the spinal canal outside the membranes that surround the spinal cord and spinal nerves.  Scar tissue can develop in the epidural space after any open surgical procedure or minimally invasive procedures that are associated with bleeding.

Open surgical procedures, which are associated with scar tissue development, include spinal fusion, laminectomy, and microdiscectomy.  It is normal for some scar tissue to develop after a surgical procedure, although it is usually not associated with symptoms.  In a relatively small percentage of cases scar will contribute to abnormal signs or symptoms.  Scar tissue is often referred to as fibrosis.  The term fibroproliferation refers to the progressive development of scar tissue.

Scar tissue can contribute to intractable pain via a number of different mechanisms.  It can limit tissue movement and cause inflammation.  Scar tissue (fibrosis) can adhere to spinal nerve roots.  It can also create adhesive or restrictive bands between adjacent spinal structures.  Scar tissue tends to be very vascular with a dense blood supply subsequently when it is physically stretched it tends to bleed easily.  This type of recurrent injury sets the stage for additional scar formation (fibroproliferation).  Epidural scar (fibrosis) can develop within 2-12 weeks of surgical intervention.

Clinically significant scar formation in the low back is usually characterized by gradual progression of low back pain and the development of slowly progressive pain extending into one or both legs.  Individuals who have restrictive scar in the low back tend often experience increased pain during any movement or activity that stretches the involved tissues.  Repeated injuries to a region with adhesive scar tissue can lead to recurrent small (micro) vessel bleeding and changes in the physical characteristics of scar.