Efficacy of Injections
Potential Benefits of Injections
Epidural steroid injections deliver medication very close to the source of where the pain is generated. In contrast, oral steroids and painkillers have a dissipated, less-focused impact and may have undesirable side effects. Additionally, since the overwhelming majority of pain comes from chemical inﬂammation, an epidural steroid injection can help control local inﬂammation while also ridding the body of inﬂammatory proteins and chemicals from the local area that may contribute to the pain.
How Do Steroid Injections Work?
An epidural steroid injection delivers steroids directly into the epidural located in the spine. Sometimes a local anesthetic and/or normal saline solution is used to help ﬂush inﬂammatory mediators from around the area where the pain is located. The epidural space encircles the dural sac and is ﬁlled with fat and small blood vessels. The dural sac surrounds the spinal cord, nerve roots, and cerebrospinal ﬂuid (the ﬂuid that the nerve roots are bathed in). Typically, a solution containing the steroid cortisone with a local anesthetic such as lidocaine, and/or saline is used.
- A steroid is an anti-inﬂammatory agent that is injected and is a common component of many low back conditions and results in less inﬂammation which helps to get rid of the pain. Dexamethasone and methylprednisolone acetate are also commonly used steroids.
- Lidocaine is a fast-acting local anesthetic used for temporary pain relief. Bupivacaine, a longer lasting medication, may also be used.
- Saline is used for diluting the local anesthetic or as a ‘ﬂushing’ agent to dilute the chemical agents that promote inﬂammation.
Epidural Steroid Injections Control Inflammation
Epidural injections are often used to treat radicular pain, also called sciatica, which is pain that stems from the area of a pinched nerve in the lumbar spine to the location of the body that connects to that particular nerve, such as the leg or even as low as the foot. Inﬂammatory chemicals and immunologic mediators can create pain and are associated with common back issues such as lumbar disc herniation. These conditions provoke inﬂammation that in turn can cause signiﬁcant nerve root pain and swelling. Epidural steroid injections inhibit the inﬂammatory response caused by chemical and mechanical sources of pain. These steroids also work by reducing the activity of the bodies immunity to react to inﬂammation associated with nerve or tissue damage. A typical immune response is a body generating white blood cells and chemicals to protect it from infection and foreign substances such as bacteria and viruses. Inhibiting the immune response with an epidural steroid injection can reduce the pain associated with inﬂammation.
Indications for Lumbar Spinal Epidural Injections
Several common conditions that cause severe acute or chronic low back pain and/or leg pain (sciatica) from nerve irritation can be treated with steroid injections. These conditions include:
- Compression fractures in a vertebra.
- An annular tear which is a painful condition where a tear is present in the outer layer of the disc.
- Lumbar spinal stenosis which is a narrowing of the spinal canal that pinches nerves and the spinal cord causing signiﬁcant pain.
- Degenerative disc disease where the breakdown of the disc space may impinge on nerves in the lumbar spine.
- Cysts which are located in the facet joint or the nerve root and can expand to impinge spinal structures.
Who Should Avoid Epidural Steroid Injections
Several conditions where a patient should not receive an epidural injection:
- Local or systemic infection
- If you are taking blood thinners
- If pain is related to a tumor
Preparing for an Epidural Steroid Injection
Patients may be asked to change into a hospital gown which allows access to clean the injection area and to allow the physician to easily visualize the injection site. An epidural steroid injection usually takes between 15 and 30 minutes and follows a relatively standard protocol.
Additional Injections Info:
The patient lies ﬂat on an X-ray table with a small pillow under their stomach to slightly curve the back. Sometimes the patient can be allowed to sit up or lie on their side in a slightly curled position.
The skin in the lower back area is cleaned and anesthetized with a local anesthetic.
Using ﬂuoroscopy, which is a live x-ray used for guidance, a needle is injected toward the epidural space. Fluoroscopy plays an instrumental role in guiding the needle into the epidural space.
Once the needle is placed in its proper position, a contrast is injected to conﬁrm where the needle is located. The epidural steroid solution is then inserted. Although the steroid solution is injected slowly, most patients sense some pressure due to the amount of the solution used. The pressure of the injection is not generally painful.
Following the injection, the patient is monitored for 15 to 20 minutes before being discharged home.
Sedation is available for patient anxiety and comfort. However, sedatives are rarely necessary as the epidural steroid injection procedure is usually not uncomfortable. If a sedative is used, some patient precautions should be taken, including not eating or drinking for several hours prior to the procedure and having a guardian available before leaving the hospital.
Soreness at the needle injection point can be an issue for a few hours after the procedure and can be alleviated by applying ice for a few minutes every hour. In addition, patients are usually asked to rest for the remainder of the day on which they have the epidural steroid injection. Your normal daily activities may typically be resumed within 24 hours. A temporary increase in the pain can occur for several days after the injection due to the pressure of the ﬂuid injected or due to local chemical irritation.
Number and Frequency of Injections vary
Generally speaking, the consensus is to perform up to three epidural injections per year.
- Some doctors will space the injections out evenly over a year.
- Other doctors administer two to three epidural injections within a 2-5 week span.
There is no general consensus in the medical community as to whether or not a series of three injections should be performed. If the patient ceases to report pain after the first shot, no further injections may be necessary.
Injection Success Rates
While the effects of an epidural steroid injection tend to be temporary (lasting anywhere from a week to a year) an epidural steroid injection can deliver substantial beneﬁts for many patients experiencing lower back pain.
Lumbar epidural steroid injections are successful in patients with persistent sciatica from lumbar disc herniation, with more than 80% of the injected group with disc herniation experiencing relief.
Similarly, in a study focused on a group of patients with lumbar spinal stenosis and related sciatica symptoms, 75% of patients receiving injections had more than 50% of pain reduction one year following the injections. The majority also increased their walking duration and tolerance for standing.
When proper placement is made using ﬂuoroscopic guidance and radiographic conﬁrmation through the use of contrast, about 50% of patients receive pain relief as a result of an epidural steroid injections.
Pain relief is more often found in the legs than in the back.
The pain relief and control brought on by injections can improve a patient’s mental health and quality of life, minimize the need for painkiller use, and potentially delay or avoid surgery.
Nonetheless, there is still some skepticism about the efﬁcacy and appropriateness of injections for most patients. As noted previously, much of the controversy is generated by studies that analyze injection outcomes where ﬂuoroscopy and radiographic contrast were not used to ensure accurate placement of the steroid solution at the level of pathology, or do not conﬁrm that the injection was in fact made directly into the epidural space which would diminish its effectiveness considerably.
Potential Risks of Epidural Steroid Injections
As with all invasive medical procedures, there are potential risks associated with lumbar epidural steroid injections. In addition to temporary numbness of the bowels and bladder, the most common potential risks and complications include:
Epidural steroid injection.
Infection. Severe infections are very rare.
Dural puncture (“wet tap”). A dural puncture occurs in 0.5% of injections. It may cause a post-dural puncture headache (also called a spinal headache) that usually improves within a few days. Although infrequent, a blood patch may be necessary to alleviate a headache. A blood patch is a simple, quick procedure that involves obtaining a small amount of blood from a patient from an arm vein and immediately injecting it into the epidural space to allow it to clot around the spinal sac and stop the leak.
Bleeding is a rare complication and is more common for patients with underlying bleeding disorders.
While extremely rare, nerve damage can occur from direct trauma from the needle or from infection or bleeding.
Possible Side Effects of Lumbar Epidural Steroid Injection
In addition to risks from the injection, there are also potential side effects from the steroid medication itself.
- A decrease in immunity because of the suppressive effect of the steroid
- Headaches dissipating within 24 hours
- Stomach ulcers
- Arthritis of the hips
- Fever the night of injection
- Facial ﬂushing
- Localized increase in pain
- High blood sugar