Sciatica

Most patients have heard the phrase "sciatica". The term sciatica is used for descriptive purposes only. What most patients are unaware of is that the sciatic nerve is the least likely anatomical structure involved in causing their low back and leg pain. The term radiculopathy (dysfunctional nerve root) is much more accurate. Radiculopathy refers to compression or irritation of a spinal nerve, as it leaves your spinal canal, resulting in low back pain radiating into the buttock and/or leg.

Fig 2. Typical anatomy of the sciatic nerve
Fig 3. S1 nerve irritation (pink) secondary to a herniated disc at L5-S1. Note how the irritated S1 nerve root eventually becomes part of the sciatic nerve (orange).

 

The main causes of radiculopathy include:

• Lumbar Disc Herniation. A disc herniation is the most common cause of sciatica. You may be familiar with the terms protrusion, extrusion, sequestration, or bulging. A qualified spine physician may explain how of each of these descriptive terms may be relevant to your problem.
• Spinal Stenosis. The term stenosis simply means, "narrowing". There are three main types of stenosis
  • Central canal stenosis
  • Foraminal stenosis
  • Lateral recess stenosis.
  
  The fancy medical naming of each type of stenosis is unimportant for this basic discussion. In general, stenosis usually refers to arthritic that your spinal nerve(s) must pass through and exit to leave your spinal column and travel to your leg.
  
  The narrowing can actually be secondary to a combination of factors
  • Arthritic narrowing
  • Lumbar Disc herniation
  • Spondylolisthesis
  • Compression from a degenerative cyst

Most cases of sciatica do not require surgery. Whether your sciatica symptoms are caused by a disc herniation or spinal stenosis, you have a good chance of recovery with non-surgical treatment. Surgery is reserved only for the most serious cases or those resistant to non-surgical care.

Symptoms

Symptoms of a lumbar disc herniation may include the following:

• Dull or sharp pain in the lower back, intensified by movements or activities such as bending, coughing, or sneezing.
• Muscle spasms or cramping.
• Sciatica (pain, burning, tingling, and numbness that extends from the buttock into the thigh, leg or foot).
• Leg weakness or loss of leg function.

Diagnosis

Good treatment is always based on an accurate diagnosis. A comprehensive diagnostic process includes:

• Medical history. Your physician will talk to you about your symptoms, how severe they are, and what treatments you have already tried.
• Physical examination. You will be carefully examined for limitations of movement, problems with balance, and pain. During this exam, your physician will also look for loss of reflexes in the extremities, muscle weakness, loss of sensation or other signs of spinal cord damage.
• Diagnostic tests.
  • MRI. MRI provides the most accurate three-dimensional views of the lumbar spine and can help detect herniated discs. It can also help rule out other disorders of the spine that may mimic the symptoms of a disc herniation.
  • EMG. EMG is an electrodiagnostic study (nerve test) that may help clarify definite injury to one particular nerve root. This test may also give the physician feedback as to the severity of this nerve injury.
  • Diagnostic Selective Nerve Root Block. A diagnostic selective nerve root block (SNRB) is similar to other spinal injections that a patient may undergo. However, this injection is purely diagnostic in nature (not a treatment), aiding you physician in confirming your suspected diagnosis.

Fig A. Large central disc herniation at L4-5
Fig. B Axial slices from the same MRI confirm the presence of a large bi-lobed focal protrusion.

Treatment for Sciatica

Most cases of sciatica do not require surgery. Whether your sciatica symptoms are caused by a disc herniation, foraminal stenosis, or lateral recess stenosis, you have a good chance of recovery with non-surgical treatment. Surgery is reserved only for the most serious cases or those resistant to non-surgical care.

Non-Operative Treatment

A combination of the following treatments will be used with most sciatica patients:

• Medications
  • Anti-inflammatories: to reduce swelling and pain
  • Narcotic painkillers: to alleviate acute pain (only if absolutely necessary)
• Physical therapy. An exercise prescription tailored to your condition will be prescribed to direct your physical therapist. A typical prescription involves:
  • Stretching exercises
  • Strengthening exercises
  • Core stability training
  • Balance training
• A therapeutic selective nerve root block (SNRB) series
  • Most patient s will benefit form a type of pinpoint epidural injection, under live x-ray guidance, of a strong anti-inflammatory medication (corticosteroid).
  • Maximum benefit typically occurs following 2 to 4 injections

Percutaneous Disc Decompression

The following procedure is specific for patients with sciatica symptoms as a result of a disc herniation: Although most patients improve with conservative non-invasive therapy (see "Non-operative Treatment" above), numerous patients continue to experience significant pain. Open surgical procedures are available; however, these procedures are associated with a small, but not insignificant, risk of complications such as nerve root injury, excessive scarring around nerve roots, mechanical instability, bleeding, and infection. It has therefore becomes increasingly important that spine specialists consider minimally invasive procedures for these patients and progress to more invasive interventions only if they become necessary.

This desire for a minimally invasive option for treatment of spine pain led to the development of numerous percutaneous techniques (non-surgical techniques using probes that are directed through the skin and muscle, down to the problem area in the spine using x-ray guidance). These procedures have demonstrated good to excellent results 70–75% of the time. For patients with a symptomatic focal disc protrusion (type of herniated disc), unresponsive to more conservative measures, percutaneous disc decompression has become the standard of care in interventional spine management. The implementation of this treatment option has dramatically reduced the number of patients ultimately needing lumbar surgery.

Percutaneous Disc Decompression (PDD) is a minimally invasive procedure performed under live x-ray guidance with the goal of removing a small amount of nuclear disc material (jelly-like substance in the centre of your disc) from your herniated disc. This decreases the pressure inside the disc (like deflating a water balloon), thus relieving the pressure transmitted to your nerve root. The ultimate goal is to relieve your symptoms of leg pain with or without back pain (otherwise known as "sciatica" or "radiculopathy").

Surgical Treatment

If after a full course of interventional/medical management the patient still has intolerable pain, or if there is evidence of neurological deficit (e.g. significant weakness and/or numbness) then you may be recommended for surgery to relieve the irritation or compression of the injured nerve.