The L4-L5 spinal motion segment is located in the lower portion of the lumbar spine. This motion segment is connected by a 3-joint complex: An intervertebral disc in the front, which acts as a shock absorber between adjacent vertebrae, and – a pair of facet joints in the back, that allow limited forward, backward, and twisting motions.
Aging-related degeneration of the facets and discs may make them less capable of bearing loads, resulting in a weakening of the 3-joint complex and gradual slippage of one vertebral body on top of the vertebra below it.
This condition is called degenerative spondylolisthesis and occurs most frequently at the L4-L5 spinal motion segment.
A grading system is used to measure the degree of vertebral slippage in degenerative spondylolisthesis. There are 4 grades ranging from grade 1 to grade 4, and each grade represents a progressively greater degree of forward displacement of the vertebra.
Vertebral slippage in degenerative spondylolisthesis rarely exceeds grade 2.
The symptoms are usually mild and occur due to the inflammation or compression of the L4 spinal nerve.
The most bothersome symptom of L4-L5 degenerative spondylolisthesis is neurologic claudication, which occurs due to the mechanical compression of nerves in the spine.
Neurologic claudication is characterized by episodes of low back pain that radiates to both legs, along with sensations of tingling, numbness, weakness, and hamstring spasm.
L4 nerve root irritation or compression may also cause sciatica or radiating nerve pain in the leg, which typically affects one side.
In some cases, severe compression of the L4 nerve root may cause lumbar radiculopathy – characterized by leg weakness and numbness.
L4-L5 degenerative spondylolisthesis is typically treated with self-care, medication, physical therapy, and injection treatments. A wait-and-watch approach is used to see if the symptoms resolve with these non-surgical treatments. In rare cases, lumbar spine surgery, such as lumbar laminectomy or lumbar spine fusion may be considered.
