Spinal Injections

Spinal Injections

When you visit a spine specialist, you will undergo a thorough work-up. The physician will ask you questions about your neck or back pain, perform a physical examination and order any necessary investigations (x-ray, CT Scan, MRI, etc.) This detailed assessment will provide your physician most of the information necessary to make an accurate diagnosis for your condition.

However, it is often difficult and sometimes impossible to be 100% about the diagnosis by this initial assessment. Often, spinal injections, typically used to treat pain, are also used diagnostically to locate the pain source. The spine physician will perform this injection under live x-ray guidance to precisely place local anesthetic (numbing medication) around or inside the suspected source of pain. If you obtain significant relief from this injection, it is likely that the true diagnosis has been found.

Once your physician is confident about the diagnosis, you may be a candidate for therapeutic (treatment) injections. Most therapeutic spinal injections use a powerful anti-inflammatory medication called corticosteroids. The goal of the injection is to place a small amount of this potent anti-inflammatory medication exactly where the pain begins (e.g. joint, nerve). Under live x-ray guidance, your spine physician has the ability to precisely instill this medication where it will provide the greatest benefit to your spine problem.

Spinal injections include:

Selective Nerve Root Block (SNRB)

Diagnostic SNRB. A diagnostic SNRB is performed to determine if a specific spinal nerve is the source of pain. It can help to diagnose cervical, thoracic or lumbar radiculopathy (irritation and inflammation of a nerve root serving a particular body part). Under fluoroscopic (live x-ray) guidance, the specialist injects numbing medication at a specific nerve root. If the injection reduces or alleviates the patient’s symptoms, then the source of pain is located. Occasionally, the injection will need to be repeated to rule out a false-positive (placebo) response.

Therapeutic SNRB. A therapeutic SNRB is performed to reduce pain and inflammation around a specific spinal nerve. This procedure is also referred to as a transforaminal epidural steroid injection (TFESI). It is used to treat cervical, thoracic or lumbar radiculopathy (irritation and inflammation of a nerve root serving a particular body part). Under fluoroscopic (live x-ray) guidance, the specialist injects steroid medication and local anesthetic at a specific nerve root.

Transforaminal Epidural Injection (TFESI)

A TFESI is similar to a selective nerve root block (SNRB). It is performed to reduce pain and inflammation around a specific spinal structure. This structure may be the spinal nerve. However, the physician may also attempt to reduce the inflammation around nearby spinal structures such as a disc, nerve plexus, and blood vessels. It is used in the cervical, thoracic or lumbar spine to treat a number of conditions (radiculopathy, spinal stenosis, degenerative disc disease). Under fluoroscopic (live x-ray) guidance, the specialist injects a local anesthetic and steroid medication at a spinal level.

Medial Branch Blocks (MBBs) & Facet Joint Injections

Diagnostic injections. Facet joint injections and medial branch blocks involve the injection of numbing medication into the joint or around the appropriate nerves to determine if that facet joint is a pain generator. A facet joint block is an injection of local anesthetic medication into the joint. A medial branch block uses similar medication injected outside the joint space near the nerve that feeds that joint. These injections are performed in the cervical, thoracic or lumbar spine under fluoroscopic guidance. If pain is relieved, it could mean that the suspected joint is the pain generator.

It is important to understand that this particular injection has a high placebo rate. This means that up to 38% of patients who DO NOT have true facet joint pain, will feel relief with a single diagnostic injection. The diagnostic injection must be repeated on a separate occasion to ensure that the patient’s response is a true positive…i.e. that facet joint is the true pain generator.

Therapeutic Intra-articular facet injections. Joint inflammation may play a leading role in back pain. Steroids reduce inflammation and alleviate pain. After at least two diagnostic intra-articular facet injections or medial branch blocks have been performed to confirm the diagnosis of facet joint related pain, subsequent injections with steroid medication into the joint may provide tremendous relief.

Medial branch blocks Joint inflammation may play a leading role in back pain. Steroids reduce inflammation and alleviate pain. After at least two diagnostic intra-articular facet injections or medial branch blocks have been performed to confirm the diagnosis of facet joint related pain, subsequent injections with steroid medication into the joint may provide tremendous relief.

Each cervical, thoracic or lumbar facet joint receives sensory innervation from two small nerve branches. These branches are called the medial branches (of the dorasal rami). If you numb these nerve branches, you temporarily take sensation away from that joint. Medial branch blocks involve the injection of numbing medication (local anesthetic) around these sensory nerves to determine if that facet joint is a pain generator. These injections are performed under fluoroscopy. If pain is relieved, it could mean that the suspected joint is the pain generator.

It is important to understand that this particular injection has a high placebo rate. This means that up to 38% of patients who DO NOT have true facet joint pain, will feel relief with a single diagnostic injection. The diagnostic injection must be repeated on a separate occasion to ensure that the patient’s response is a true positive, i.e. that facet joint is the true pain generator.

Sacroiliac Joint Injection

Diagnostic sacroiliac joint injection. Dysfunction in the sacroiliac joint is thought to cause low back and/or leg pain. The sacroiliac joint is the “chameleon” of the spine; SIJ dysfunction can mimic the pain caused by a number of other spinal structures (lumbar disc, nerve root, facet joint). The pain is typically felt on one side of the low back or buttocks, and can radiate down the leg. The pain usually remains above the knee, but at times pain can extend to the ankle or foot. Accurately diagnosing sacroiliac joint dysfunction can be difficult. A diagnosis is usually suspected by the physical examination and then confirmed with an injection under fluoroscopic (live x-ray) guidance.

A sacroiliac joint injection (block) requires a highly skilled and experienced physician to be able to insert a needle into the correct portion of the sacroiliac joint. In this test, the spine physician uses local anesthetic, usually lidocaine (“numbing” medication). If the injection relieves your pain, it provides much stronger proof (than physical exam alone) that the sacroiliac joint is the source of your pain.

Therapeutic sacroiliac joint injection. SIJ dysfunction can mimic the pain caused by a number of other spinal structures (lumbar disc, nerve root, facet joint). Similar to these other spine disorders, SIJ pain may have an inflammatory component.

A sacroiliac joint injection requires a highly skilled and experienced physician to perform an injection under fluoroscopic (live x-ray) guidance. The needle must be carefully guided into the correct portion of the sacroiliac joint. Once the physician has confirmed proper placement of the spinal needle into the bottom of the joint, steroid medication and local anesthetic are injected.

In some cases, the ligaments, which support the sacroiliac joint, represent the actual pain source. The reason for this is the ligaments are rich in nerve endings capable of delivering pain messages. In these cases, injecting medication inside the joint will be ineffective. In order to freeze the ligaments of the sacroiliac joint, there are two ways to perform the diagnostic procedure:

• The physician may block the complex series of small sensory nerve fibres that travel to the sacroiliac joint. These nerve fibres are the lateral branches off of the dorsal rami at S1, S2, and S3. You may be counseled toward the completion of a Lateral Branch Block (LBB), if your physician believes the ligaments of the sacroiliac joint are causing your pain.
• Some physicians prefer to directly inject the dorsal ligaments themselves.

Hip Joint Injections

It is not uncommon for patients with low back to develop symptoms that travel into the hip and groin region. Differentiating between a hip disorder and a lumbar spine (low back) disorder may be difficult, even for an experienced physician. Performing a diagnostic injection under fluoroscopic (live x-ray) guidance can help clarify the diagnosis.

With the patient lying on their back the hip joint is easily visualized under x-ray. A spine needle is introduced into the front aspect of the hip joint. Radioopaque contrast (x-ray dye) is then injected to ensure good flow into the joint. Then the physician will inject local anesthetic (numbing medication) into the joint.

After the injection, you will be asked to walk or stand to recreate your hip/back pain symptoms. If you are pain free, it is likely the hip joint plays a major role in your daily discomfort.

Discography

Discography is a test used to determine whether the suspected disc  (clinical exam and radiological findings) is the true source of pain in patients with predominantly axial back or neck pain (DDD, IDDS). During the procedure, x-ray contrast (dye) is injected into the suspected disc as well as adjacent “normal” looking discs. Next, the patient’s response to the injection is noted. If the test reproduces your typical, daily back or neck pain, this suggests that the disc is likely the source of the pain. A CT scan must be performed immediately after the discogram to better assess the anatomical changes in the disc. For the test to be valid, the CT scan must reveal contrast leaking into tears on the inside of the disc; thus demonstrating the expected disruption of the annular fibres.

Specific indications for discography include the following:

1. Persistent, severe symptoms when other diagnostic tests have failed to clearly confirm a suspected disc as a source of the pain.
2. Evaluation of recurrent pain from a previously operated disc.
3. Assessment of patients in whom spine surgery has failed to provide relief.
4. Assessment prior to spinal fusion surgery to identify symptomatic discs. Also, the surgeon may want to know whether the discs adjacent (next to) to the segment can support the stress of fusion.
5. Assessment of candidates for minimally invasive procedures such as percutaneous discectomy (disc herniation), or intradiscal modulation (internal disc disruption syndrome)

Common complications associated with discography include: nausea (2%), seizures (4%), headache (10%), and increased pain (81%).
Rare, but serious complications include spinal headache, meningitis, discitis (disc infection), arachnoiditis (scarring), allergic reaction, and bleeding.

Patient Preparation for Injection Procedures: At Home

It is important that the patient follow all pre-test instructions so that the results of the diagnostic injection are accurate. Some of these instructions include:

• Stop blood-thinning medication (e.g. Coumadin) 5 days prior to the test
• Do not take any aspirin product 3 days prior to the test
• Stop anti-inflammatory medication 3 days prior to the test (Celebrex™ is an exception)
• Stop pain medication 8 hours prior to any diagnostic injection
• Alert medical staff to any allergies
• Some procedures require the patient to avoid eating and drinking for 6 hours prior. You will be instructed when this is appropriate.

Patient Preparation for Injection Procedures: At the Medical Facility

• The medical staff will review the patient’s history, condition, medications taken on a daily basis, food and/or drug allergies, and other information.
• After changing into a gown, the patient is brought into the procedure room and placed in the appropriate position.
• Depending on the procedure being performed, a nurse may need to start an I.V. in your arm.
• An automatic blood pressure cuff (blood pressure) and oximeter (measures blood-oxygen levels) are attached to the patient. This equipment enables the medical staff to consistently monitor the patient’s vital signs before, during, and after the procedure.

What to Expect During the Procedure

Set-up:

• The procedure is performed 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.
• Before proceeding, the fluoroscopy C-arm is positioned over the patient. Fluoroscopic guidance is used during the procedure to guide the needle into the proper position.

Injection Procedure — Diagnostic and Therapeutic Injections:

• Brief, mild discomfort (one or two seconds) from the local anesthetic (numbing medication) placed at the skin site (like getting a tooth frozen at the dentist).
• Little to no discomfort when directing the spinal needle to the target
• Once the needle has reached the target site, little or no discomfort it typically felt when the contrast (x-ray dye) is instilled (double-checking for accurate needle position).
• After confirming accurate flow of the contrast, the diagnostic or therapeutic medication is injected. Depending on the patient’s condition, they may briefly (few seconds) feel mild pain or pressure, as the medication is injected in or along the anatomical target (because that structure may be inflamed or irritated).

Injection Procedure — Discography: In contrast to diagnostic “blocks”, the goal of provocative discography is to replicate the patient’s typical discomfort (symptoms). The patient’s experience is similar to the that of a typical diagnostic block, until the final step:

• Brief, mild discomfort (one or two seconds) from the local anesthetic (numbing medication) placed at the skin site (like getting a tooth frozen at the dentist).
• Little to no discomfort when directing the spinal needle to the target
• Once the needle has reached the target site, inside the disc, they will typically feel one of  two sensations as the contrast (x-ray dye) is instilled into the middle of the disc:
  • If the disc is not a source of pain, they may feel absolutely nothing or they may feel pressure.
  • If the disc is their source of pain, they will feel moderate pain that replicates their daily pain experience (re-creates “your” pain).

Injection Procedure — Radiofrequency procedures: to be discussed in a separate section on this website.

After the Procedure

• The patient is wheeled to the recovery area where the medical staff continues to monitor the patient.
• Patients are usually discharged home within 30-60 minutes with post-op instructions.
• The area around the injection site will feel numb for one to two hours following the injection.
• Steroids may cause side effects that may last for 2 to 3 days:
  • Temporary flare (worsening) of your pain
  • Headache
  • Flushing (face red and sweaty)
  • Difficulty sleeping
  • Irritability
  • Water retention

Possible Complications

Diagnostic spinal injections, like other medical procedures, have risks.  The most important complications to be aware of are the risk of infection or bleeding. Although these are very rare events (~1/100,000 to 1/50,000), if they occur, you may need emergency treatment such as hospitalization, IV antibiotics, or even open surgery.

Patient Restrictions

For their safety, some patients may not be allowed to undergo diagnostic spinal nerve injections for the following reasons:

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