Developed spinal stenosis is also commonly called acquired spinal stenosis, since it is not dependent on congenital canal narrowing or inborn conditions that will inherently lead to a reduction in the patency of the spinal canal over time. In essence, developed stenosis occurs due to factors that are not present from birth or created due to birth abnormalities.
Virtually all adults will develop some form and degree of spinal stenosis as they age. This is because stenosis is a normal part of getting older that most often affects people in multiple regions of the spine. The cervical and lumbar zones are the hotspots of stenotic activity, but central and foraminal canal narrowing can occur anywhere in the length of the vertebral column and are usually present to some extent in several areas at once, starting in the 4th decade of life.
This discussion explores how and why spinal stenosis may be developed. We will look at the normal reasons for its presentation, as well as less common scenarios that can sometimes worsen stenosis to the point of acutely symptomatic degrees.
Developed Spinal Stenosis Anatomy
Stenosis occurs when normal anatomical passageways become less patent than is deemed typical. Stenosis occurs in many areas of the body, including nerve passageways, blood vessels and digestive structures. When it comes to the spine, stenosis has 2 primary targets and these are the central vertebral canal, also called the central spinal canal, and the foraminal openings, also called the neuroforamen.
In central stenosis conditions, the primary vertebral passageway is narrowed at one or more locations. This is the space through which pass the spinal cord and massed spinal nerves, called the cauda equina. In foraminal stenosis conditions, one or more openings that allow the individual nerve roots to exit the spine are narrowed.
Both the central and foraminal canals are more than large enough to accommodate mild to moderate stenosis without the patient suffering any ill effects. However, when the stenosis reaches a degree where the contained neurological tissue suffers compression, then symptoms are likely to occur and might become severe in cases of dramatic patency reduction.
To summarize this section, imagine a tube or opening with nerves running through it. If the tube collapses or the opening closes, then the nerve signal will be interrupted and this is why painful symptoms might result from clinically severe stenosis. However, it is crucial to know that even extreme forms of stenosis are not inherently symptom-generating.
Spinal Stenosis Development
Stenosis is now viewed medically as a completely normal and expected process that will affect virtually every adult at some point in life. Most adults will demonstrate the beginnings of spinal stenosis in their 30s and will almost certainly present mild cases past the age of 40. Stenosis progresses as long as life endures.
Age and activity are the main reasons why people develop stenosis. Both of these factors contribute to the breakdown of the spinal spacers, called intervertebral discs, as well as the deterioration of the protective measures of the spinal bones by the process of arthritis. When the spinal discs degenerate, the bones become closer together and interact more often and with more force. This facilitates the arthritic processes, which cause breakdowns in the spinal joint structures and the growth of osteophytes on skeletal surfaces. Another common contributor to spinal stenosis development is intervertebral herniation that is created due to degeneration and loss of integrity of the disc structures.
Less common, but still relatively frequently seen contributors to spinal stenosis include ligamentous conditions, spinal curvature abnormalities and vertebral subluxations. Ligamentous hypertrophy and ossification can both narrow the spinal or foraminal canal spaces. Scoliosis, hyperlordosis, hyperkyphosis, hypolordosis and hypokyphosis can all reduce the patency of the central or neuroforaminal canals. All forms of spondylolisthesis, including anterolisthesis and retrolisthess, can also diminish the effective size of both the central and foraminal canals.
There are also other nonorganic reasons why stenosis might occur or be exacerbated due to the conditions listed in the section below.
Developed Spinal Stenosis Factsheet
Not all stenosis is deemed normal given the general condition of the patient’s spine. Some instances of stenosis are caused or contributed to by case-specific factors that can relate to many different occurrences, including those detailed below:
Injury to the spine can instigate any of the contributing factors detailed in the above section. Injury can also cause unspecific contribution to the development of spinal stenosis due to scar tissue or the accumulation of debris in the spinal canal or foraminal spaces.
Certain neuromuscular diseases and conditions can pull the spine so dramatically that the spinal canal might suffer stenosis that might be transient or permanent.
Spinal surgery is one of the more common contributors to all types of stenosis. Surgery can also facilitate any of the contributing factors listed above or may directly create a loss of patency in the central canal space. Surgery might also cause the build-up of scarring osteophytes on or around the neuroforamen. Spinal fusion, corpectomy and some types of spinal implants are the worst offenders. Laminectomy is a moderate cause of postoperative stenosis, while discectomy is a relatively uncommon contributor.