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Understanding Medical Tests:
DIAGNOSTIC INJECTIONS

X-rays, CT Scans, and MRIs provide excellent imaging of different spinal disorders.  However, these tests do not show or reproduce pain.  Spinal injections, typically used to control pain, can be used diagnostically to locate the pain source.  Diagnostic spinal injections include discography (discogram), selective nerve root blocks (SNRB), sacroiliac joint injections, facet joint injections, and medial blocks.

Discography

DiscogramDiscography is a specific test to tell if a damaged or abnormal disc is causing pain.  This is not a routine test.  It may be performed prior to spinal disc surgery to determine which disc levels will be treated.  

Discography, an invasive procedure, is performed using fluoroscopy (similar to x-ray, except in real time). The patient is awake but receives relaxing medication and antibiotics intravenously. The patient is positioned using cushions to give the physician access to the discs to be examined. The injection sites are cleansed using an antiseptic and a local anesthetic numbs the skin.

Using fluoroscopic guidance, a contrast agent (dye) is injected into the center of select discs.  Contrast enhances the disc’s anatomical characteristics and may spread outside the disc if abnormal.  

As each disc is injected with contrast, the patient is asked to describe symptoms, such as the intensity and type of pain experienced.  When discography replicates symptoms, it is called a positive discogram.  If symptoms are not replicated, it is a negative discogram.  Discography can be uncomfortable and symptoms are temporary. Patients should tell the medical staff if symptoms are intense.

The procedure may up to an hour, depending on the number of discs examined.

Learn More about Diagnostic Discography

Selective Nere Root Block (SNRB)

A selective nerve root block is performed to determine if a specific spinal nerve is the source of pain.  A SNRB is performed to diagnose cervical (neck) or lumbar (low back) radiculopathy (irritation and inflammation of a nerve root).

Using fluoroscopic guidance, steroid medication (a strong anti-inflammatory) is injected at a specific nerve root   If the injection reduces symptoms, the pain source is identified.  The test takes 15- to 30-minutes per spinal level.

Sacroiliac Joint (SIJ) Injection

SIJ v2The sacroiliac joint, located in the lower spine above the tailbone, is the largest joint in the spine.  Inflammation of the sacroiliac joint can cause low back and buttock pain.  

Using fluoroscopy, local anesthetic is injected into the sacroiliac joint.  If pain is relieved, it may mean the joint is the pain generator.  Once the sacroiliac joint has been identified as the pain generator, treatment can be targeted to the joint itself .

Learn More About Sacroiliac Joint Injections

Facet Injections & Medial Branch Blocks

Joint inflammation between spinal bones can cause back pain.  Facet and medial blocks involve injecting steroid medication into one or more joint structures to determine if a specific joint generates pain.  

  • A facet joint block is an injection of local anesthetic and steroid medication into the joint.  
  • A medial block uses similar medication injected outside the joint space near the nerve that feeds a specific joint.  
  • Both injection procedures are performed using fluoroscopy.

If pain is relieved, it may mean that the joint or medial nerve generates pain.

Learn More About Cervical Medial Branch Blocks

Learn More About Lumbar Medial Branch Blocks

What to Expect

Before the Procedure
The medical staff will provide individual patients with specific instructions in advance of these tests. Following are some common guidelines.

  • Blood thinners should be stopped two days prior to the test
  • Aspirin should be stopped five days prior to the test
  • Anti-inflammatory medications should be stopped five days prior to the tests
  • Pain medications should be stopped eight hours before the test
  • No food or drink should be consumed six hours before the test
  • Patients should arrive for someone to drive them home

Once You Get Here
The medical staff will interview the patient about his or her medical history, current condition, medications, allergies, and other pertinent information. The patient will be asked to change into a hospital gown.

Before the procedure, a nurse will moniotor heart function (EKG), blood pressure, blood-oxygen levels (finger oximeter), and other vital signs. The nurse will continue monitoring during and following the test.

Patients are awake during diagnostic spinal injections and may be asked questions by the medical team during the test. An intravenous line is placed and patients are given medications to help them relax.

The Procedure
doctor talking to manDiagnostic spinal injections are administered in a sterile setting similar to an operating room. The injection site is cleaned and draped.  Skin-numbing medication is injected into and around the procedure site.

The procedure is done under fluoroscopy, which operates like video X-ray (real-time X-ray images). Before the procedure, the C-arm (named for its characteristic C-shape) of the fluoroscope will be positioned over the patient. The fluoroscopic images are projected on monitors in the operating room, allowing the physician to see precisely where the injection occurs.

Discography involves the injection of a contrast medium (dye) to enhance visualization on fluoroscopy.

The goal of discography and certain diagnostic injections is to reproduce typical symptoms. As such, a diagnostic spinal injection may be temporarily uncomfortable. The physician will ask the patient about symptoms during the test.

Other diagnostic injections may relieve symptoms. Again, the physician will ask for patient feedback during the procedure.

After The Procedure
Following the procedure, the patient is brought to a recovery area where the nurse continues to monitor the patient. The area around the injection site may be numb for several hours. At discharge, usually within the hour, patients are given written instructions for home care.

If the diagnostic injection involved steroids, patients may be counseled about rare but potential side effects including:

  • Blurred vision
  • Frequent urination
  • Changes in blood sugar levels.

In the case of persistent, severe, or unusual side effects, patients should contact the physician. If fever, chills, increased pain, weakness or loss of bowel/bladder function occurs, do not contact the doctor but call for emergency medical assistance at once. These may be associated with an urgent problem.

Possible Complications

Diagnostic spinal injections, like other medical procedures, are associated with certain risks.  Complications include risk of infection, low blood pressure, headache, and injury to nerve tissue.

Patient Restrictions

Some patients should not undergo a diagnostic injection procedure.  Patients who may not be appropriate candidates are those who are pregnant or breast-feeding or those with:

  • Allergy to the contrast medium and/or drugs to be injected
  • Anemia
  • Significant asthma
  • Bleeding problems
  • Infection
  • Kidney disease
  • Severe spinal abnormality

Diagnostic injections can be an important test in identifying the source and site of spinal pain.

The Ainsworth Institute is Here to Help

Most physicians can refer patients dealing with chronic pain to a qualified pain specialist. Pain can be complex to treat and certain types of pain may only be well controlled after treatment by a pain specialist. The experts at Ainsworth Institute offer the most advanced pain management treatments available today, including advanced clinical trials that aren’t available to the general public. Call us today for an appointment so we can get you started on your road to recovery.

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