Spinal Injections for Pain Relief

Injections comprise another relatively conservative treatment option for low back pain. They are typically considered as an option either before surgery, when surgery is inappropriate, or when residual pain exists after surgery. Injections can be useful both for providing pain relief and as a diagnostic tool to help identify the source of the patient's back pain.

When pain becomes chronic, it generally a manifests through an intense inflammatory reaction. This inflammation can be in a joint, the bone, or a nerve.

Epidural steroid injections

How an epidural steroid injection works
The most commonly performed injection is an epidural steroid injection. In this approach, a steroid is injected directly around the dura, the sac around the nerve roots that contains cerebrospinal fluid (the fluid that the nerve roots are bathed in). Prior to the injection, the skin is anesthetized by using a small needle to numb the area in the low back (a local anesthetic).

Epidural injections help reduce inflammation
Injecting around the dura sac with steroid can markedly decrease inflammation associated with common conditions such as spinal stenosis, disc herniation or degenerative disc disease. It is thought that there is also a flushing effect from the injection that helps remove or "flush out" inflammatory proteins from around structures that may cause pain.

Epidural steroid injection success rates
An epidural steroid injection is generally successful in relieving lower back pain for approximately 50% of patients. While the effects of the injection tend to be temporary (one week to one year), an epidural can be very beneficial in providing relief for patients during an episode of severe back pain and allows patients to progress in their rehabilitation.

Frequency for epidural steroid injections
There is no definitive research to dictate the frequency of the epidural steroid injections; however, a limit of three injections per year is generally considered reasonable. There is also no general consensus in the medical community as to whether or not a series of three injections need always be performed. If one or two injections resolve the patient's low back pain, some physicians prefer to save the one or two additional injections for any potential recurrent low back pain.

Generally, there are few risks associated with epidural injections. The risks are remote and include:

• A wet tap may occur, which means that the needle has penetrated the dural sac into the cerebral spinal fluid (CSF). A wet tap may result in a CSF leak and a spinal headache.
• Infection into the epidural space is also a remote risk.
• There is a remote risk of damage to a nerve root.

Selective nerve root block (SNRB)

Another common injection, a selective nerve root block (SNRB), is primarily used to diagnose the specific source of nerve root pain and, secondarily, for therapeutic relief of low back pain and/or leg pain (see Figure 1).

When a nerve root becomes compressed and inflamed, it can produce back and/or leg pain. Occasionally, an imaging study (e.g. MRI) may not clearly show which nerve is causing the pain and an SNRB injection is performed to assist in isolating the source of pain. In addition to its diagnostic function, this type of injection can also be used as a treatment for a far lateral disc herniation (a disc that ruptures outside the spinal canal).

In an SNRB, the nerve is approached at the level where it exits the foramen (the hole between the vertebral bodies). The injection is done both with a steroid (an anti-inflammatory medication) and lidocaine (a numbing agent). Flouroscopy (live x-ray) is used to ensure the medication is delivered to the correct location. If the patient's pain goes away after the injection, it can be inferred that the pain generator is the specific nerve root that has just been injected. Following the injection, the steroid also helps reduce inflammation around the nerve root.

Success rates vary depending on the primary diagnosis and whether or not the injections are being used primarily for diagnosis. While there is no definitive research to dictate the frequency of SNRB's, it is generally considered reasonable to limit SNRB's to three times per year.

Technically, SNRB injections are more difficult to perform than epidurals and should be performed by experienced physicians. Since the injection is outside the spine, there is no risk of a wet tap (cerebrospinal fluid leak). However, since the injection is right next to the nerve root, sometimes an SNRB will temporarily worsen the patient's leg pain.

Facet joint block

In cases where the facet joint itself is the pain generator, a facet block injection can be performed to alleviate the pain. Similar to SNRB's, facet block injections are a diagnostic tool used to isolate and confirm the specific source of pain for the patient. Additionally, facet blocks have a therapeutic effect as they numb the source of pain and soothe the inflammation for the patient.

The facet joints are paired joints in the back that have opposing surfaces of cartilage (cushioning tissue between the bones) and a surrounding capsule. Twisting injuries can cause damage to one or both facet joints, and cartilage degeneration associated with aging may also cause pain.

In a facet block procedure, a physician uses fluoroscopy (live x-ray) to guide the needle into the facet joint capsule to inject lidocaine (a numbing agent) and/or a steroid (an anti-inflammatory medication). If the patient's pain goes away after the injection, it can be inferred that the pain generator is the specific facet joint capsule that has just been injected.

If the facet block procedure is effective in alleviating the patient's low back pain, it is often considered reasonable for the procedure to be done up to three times per year. There are very few risks associated with this technique.

Facet rhizotomy injection

If facet block injections provide good but temporary relief of the patient's pain, a facet rhizotomy injection may be recommended. The purpose of a facet rhizotomy injection is to provide lasting low back pain relief by disabling the sensory nerve that goes to the facet joint.

In this injection procedure a needle with a probe is inserted just outside the joint. The probe is then heated with radio waves and applied to the sensory nerve to the joint in order to disable the nerve. Theoretically, by deadening the sensory nerve to the facet joint, a facet rhizotomy effectively prevents the pain signals from getting to the brain.

A facet rhizotomy injection is successful in providing lasting pain relief for approximately 50% of patients.

Before Injection, Please DO

• Take all blood pressure pills and heart medications prior to the procedure; your procedure will be cancelled if your blood pressure or other vital signs are unstable
• Have an escort to take you home; your procedure will be cancelled if you do not have an escort
• Bring the most recent spine MRI's ; we may need to cancel the procedure if adequate films are not available (this applies to only outside films not done at Stanford)
• Arrive at the above stated time, if you are not checked in at the Ambulatory Surgery Center by the above time your procedure may be cancelled
• Tell us if you have ANY allergies to medications, including contrast dye, iodine or iodine containing substances, latex, or steroids. You will require special preparation prior to the procedure & if not disclosed until the day of the procedure we may need to cancel or reschedule
• Make sure that you are not pregnant; if there is ANY chance that you are pregnant or you are unsure - let us know BEFORE the procedure date. The X-Rays used during the procedure may harm your baby.
• Before the procedure date, let us know if you have had ANY recent illnesses (last three months); including any illness which has caused fevers, chills, or any illness for which you have had to take antibiotics or was hospitalized for
• Resume all heart and blood pressure medications after the procedure
• Ask for an interpreter to be with you during the procedure if you require one

Please, DO NOT:

• Take ANY Blood thinning medications for 7 days prior to your procedure this includes any non steroidal anti inflammatory medications, such as, motrin, ibuprofen, celebrex, Naprosyn, naproxen, bextra, Vitamin E., Ginko biloba. If you are not sure- call and ask BEFORE the procedure.
• Take ANY Blood thinning medications containing aspirin or aspirin containing products for 7 days
• Plavix (clopidogrel) must be stopped for 7 days prior to the procedure
• If you are on coumadin- it must be stopped prior to the injection and you must have a normal INR prior to the injection. You must have approval from the doctor that is prescribing the coumadin before you stop taking it.
• If you are on lovenox, receiving heparin or ANY blood thinning medication it must be stopped prior to the injection, please ask us for the specific number of days to hold the medication before
• Don't eat or drink anything after midnight before the procedure. If you require heart or blood pressure medications you may take these with sips of water at least 3 hours before the above arrival time

Risks and Complications
All medical interventions have risks and benefits. Spinal injections have certain risks and complications that include:

• Spinal headache
• Bleeding (rare)
• Infection (rare)
• Certain procedures may carry other risks. Your doctor will discuss these with you if it pertains to your situation.

During the Procedure

• The procedure is usually brief, but your position during the procedure is important to make the injection go smoothly, with the least discomfort to you. You may have monitoring devices attached to you during the procedure to check your heart rate and breathing.
• Your skin will be cleaned with a sterilizing solution and a sterile drape will be placed over your skin.
• Conscious sedation (use of a calming drug while you are awake) may be used if your doctor feels it is appropriate.
• Local anesthetic (lidocaine) is usually given near the injection site to numb the skin. This typically feels like a pin prick and some burning, like a bee sting.
• Fluoroscopy (X-ray imaging) is often used for precise placement of the injection. Contrast dye may be injected to confirm the correct placement of the needle.
• A local anesthetic for numbing (eg, lidocaine, bupivicaine) and/or steroids (to reduce inflammation) is injected.
• A small bandage may be placed at the injection site.

After the Procedure

• After some injections, you may spend time in a recovery area after the procedure.
• You may be monitored to make sure you are doing well and your vital signs may be checked.
• You may be asked to fill out paper work before leaving.
• You usually should have someone drive you home.
• You may put ice packs on the injection site for 10-20 minutes at a time if there is soreness. Be careful not to burn your skin with the ice - place a towel between the ice and your skin.
• You may take a shower but avoid baths, pools or whirlpools for 24-48 hours following the procedure.
• You may be asked to relax on the day of injection, but usually can resume normal daily activities the day after the injection.
• You usually can start or resume your individualized exercise program or physical therapy program within 1 week of your injection.
• Side effects which may occur but go away in a few days include:
  • Briefly increased pain
  • Headaches
  • Trouble sleeping
  • Facial flushing
  • Hiccups
• It takes a few days, even a week or longer, for the steroid medicine to reduce inflammation and pain.
• Your doctor may want to follow-up with you in 1-3 weeks.
• If you had sedation, you probably should not drive for 24 hours after the procedure.

Link:
Acute Low Back Pain
Chronic Low Back Pain