How is spinal stenosis diagnosed?

Who to see

• General practitioner (GP) / family physician / primary healthcare provider
• Neurologist
• Orthopaedic surgeon (spine surgeon)
• Neurosurgeon

What to expect at the doctor’s office

A medical doctor will normally begin by assessing a person’s medical history and discussing the relevant symptoms being experienced. He or she may ask questions such as:

• Are you experiencing any pain? Where is pain being experienced?
• Have you noted that changes in position alleviate or worsen pain? (Standing up versus sitting down)
• Are you experiencing any unusual sensations (or lack of) such as tingling or numbness?
• Are you experiencing any degree of noticeable weakness (such as in the limbs)?
• Have you become noticeably clumsy or felt a little off balance lately?
• Are you having difficulties with controlling your bladder or bowel movements?
• Have you tried treating any of your symptoms? If so, what have you tried? Has anything helped? Or have your efforts seemingly worsened symptoms?

A doctor will then conduct a physical examination where movements will be tested and evaluated, followed by a series of recommended imaging tests. This is to assess where along the spine potential stenosis may be occurring by looking for tell-tale clues relating to characteristic symptoms.

Some tests a doctor will conduct during a physical examination include:

• Scratching of the sole of the foot – this can cause Babinski reflex (wherein the big toe goes up instead of down)
• Flicking the middle finger – the flicking of the middle finger can cause the index finger and thumb to flex, this is known as the Hoffman reflex
• He/she will also be looking for clinical signs such as increased muscle tone in the legs
• Hyperreflexia (accentuated deep tendon reflexes in the ankles and knees)
• Problems with walking, especially in tandem (placing one foot in front of the other)
• Clonus (involuntary foot movements when ankle extension is forced)

Diagnostic tests include:

• X-rays: This is to view the overall condition of the spine and assess potential abnormalities with the vertebrae. A doctor will be able to clearly see any bony changes, such as bone spurs, which may be causing compression within the spinal canal. A small amount of radiation exposure will be necessary to conduct this test. A flexion / extension lateral cervical spine x-ray may be performed to assess motion abnormalities or instability.
• MRI (magnetic resonance imaging): Using radio waves and a powerful magnet, a three-dimensional (3-D) image of the spine is created, clearly showing potential abnormalities such as disc degeneration, nerve or ligament damage, and tumours. A doctor will also be able to determine where compression along the spine is occurring, and if there are any signs of arthritis affecting the spinal cord and nerves.
• CT (computerised tomography) scan (with myelogram): X-ray technology is used to create a 3-D visual (taken from numerous different angles) of the spine with the aid of an injected contrast dye into the spinal sac fluid (usually via a vein in the arm). The dye outlines the spinal cord and spinal nerves, and highlights any potential abnormalities and damage to soft tissues, as well as problems with the bones. A CT scan is valuable for identifying potential bony causes of stenosis, but does not offer much detail on soft tissues associated with the onset of the conditions, such as disc herniations, ligament hypertrophy, and disc bulges.
• Electromyogram (EMG): Electrical activity of the muscles are measured when a person is at rest, as well as when active (i.e. muscles are being used). Nerve conduction studies will assess how quickly and effectively the nerves are able to send electrical signals (impulses) during the test.
• Bone scan: A nuclear medicine test, a bone scan uses a very small amount of radioactive material which is injected into a vein. The substance becomes a ‘tracer’ and assists a doctor in being able to identify and determine degenerative damage or potential growths on the spine.
• Selective nerve root block (SNRB): If a doctor suspects a specific nerve is affected, he or she can inject a small amount of local anaesthetic into it in order to potentially diagnose a specific source of nerve root pain. A person will then experience true temporary weakness of an associated limb which can then be evaluated as a potential source of symptoms being experienced. This process can also be used for therapeutic relief.

During the testing and evaluation procedures, a doctor will assess the location of the compression in order to determine the main type of stenosis. Accurate identification will help a doctor to diagnose and implement the most effective means of treatment.

Testing also assists a doctor in ruling out other conditions which can cause similar sets of symptoms, such as a vitamin B-12 deficiency or multiple sclerosis (MS).