History of Spinal Stenosis
The history is the patient’s story: how the symptoms began, where the symptoms are located, what is the interference in the quality of life, what relieves and what aggravates. Spinal stenosis is the narrowing of the spinal canal which reduces the space available for the nerves. Spinal stenosis commonly causes leg pain because stenosis compresses a nerve that ultimately goes down into the leg. However, the nerve compression may only cause numbness, or weakness instead of pain or may cause all or some of those symptoms in a leg. (numbness, weakness, pain). Depending on whether the stenosis is central or is located on both sides of the spine, symptoms may be in both legs because the nerves are compressed where they are grouped together in the middle (central stenosis) or are concurrently compressed on both sides of the spine (right and left). 

Most patients with spinal stenosis will have leg symptoms walking and standing but not sitting. The spinal canal is dynamically bigger or smaller depending on the patient’s posture. If the spine is bent forward, the spinal canal is bigger and therefore increases the space for the nerves. If the spine is bent backwards, the spinal canal is smaller front to back and therefore decreases the space for the nerves. When an individual sits, the spine is more flexed than when they stand or walk. Many patients with spinal stenosis will start to bend forward as they walk in an effort to increase the space in the spinal canal and provide more room for the spinal nerves. Walking while leaning on a shopping cart often makes patients with stenosis more comfortable because of the same principle of bending the spine forward to create room. 

Physical Exam of Spinal Stenosis
The physical exam is performed by the doctor to determine the effects of stenosis. An examination of the function of the nerves in the legs may reveal weakness, numbness or reflex change. In stenosis, most patients do not have dramatic physical findings. Occasionally, bending the patient backwards brings on leg symptoms for the reasons stated above.

Diagnostic Studies for Spinal Stenosis
The purpose of diagnostic studies is to answer the question, “where on the electrical diagram is the interruption that explains the patient’s clinical situation.” Diagnostic studies are designed to produce a picture of the interruption (MRI, Myelogram, C.A.T. scan) or to indicate electrical interference of the nerves. (EMG or SSEP). The diagnostic studies must correlate with (explain) the patient’s history and physical exam to be meaningful. Many tests show age related changes that exist in people who do not have pain. (there are people who have spinal stenosis who do not have any symptoms and degenerative changes are common in the spine as patients mature) 
Treatment of Spinal Stenosis

Natural History
The natural history is the rate that nature cures a particular condition. Nature has been curing things for 3 billion years and a certain percentage of patients with a particular diagnosis are going to be healed by nature. For spinal stenosis, nature does a reasonable job. Nerves exposed to very slow compression can adapt until they are squeezed at a critical limit. Stenosis symptoms are commonly slow in onset, and gradual in presentation.

A point can be reached where the spinal canal narrows so much, that there is no space available for the nerves. This is critical narrowing. Critical narrowing is a concept of lack of space. After all, the nerves occupy space and need sufficient room.Most patients will have some symptoms when and if they reach critical narrowing. What if the patients have significant narrowing? One study followed patients with spinal stenosis for 4 years without surgery, 70% stayed the same, 15% improved and 15% became worse.

Conservative Care
The purpose of conservative care is to relieve symptoms and improve function. Conservative treatment does not always “cure” but often it “relieves.” The laundry list of potential treatments for spinal stenosis includes: physical therapy, chiropractic care, injections, medications, etc.

Surgery
The goal of surgery is to take pressure off the involved nerve or nerves by removing the anatomy that causes compression. The spinal stenosis causes leg symptoms, removal of the compression allows the nerve or nerves freedom and the potential to reverse the “injury state” caused by compression. Surgery for spinal stenosis improves specific symptoms in the leg more than other symptoms. (e.g. surgery is more effective for pain relief than changing a depressed reflex back to normal).

Different surgical procedures are available which allow access to the location of stenosis and then decompress the nerves directly. The surgical strategy involves the technique chosen by the surgeon to accomplish this goal. Since spinal stenosis surgery involves altering the anatomy to free the nerve or nerves from compression, clearly understanding what anatomy needs to be changed is more important than labeling the operation with a particular title.

Conclusion
Spinal stenosis is narrowing of the spinal canal. The effect of spinal canal narrowing is to reduce the space available for the nerves. This reduction in space may lead to nerve compression and therefore symptoms in the legs. The impact of stenosis on a particular patient can vary from minimal to severe. The choice of treatment for spinal stenosis involves the patient determining how the symptoms of spinal stenosis effects the patient’s quality of life. The strategy of surgery for spinal stenosis is to alter the anatomy that causes nerve compression.