The most important cause of Lumbar Spondylosis is degeneration/aging. With age, degeneration processes cause the discs to become thinner and harder. They then provide less support to the vertebrae resting on the discs. Body compensates for this by producing small lumps of extra bone called osteophytes to better support your spine and stiffen the spine. Osteophytes can cause the spine to become too rigid leading to the symptoms of stiffness and pain. Changes in bone structure can also compress nearby nerves and blood vessels leading to pain and pressure symptoms.
Other causes of lumbar Spondylosis may also be due to injury to spine or past spinal surgery.