Interventional / Conservative Therapy
Injections comprise another nonsurgical treatment option for low back pain. They are typically considered as an option to treat low back pain after a course of medications and/or physical therapy is completed, but before surgery is considered. 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.
How Injections Relieve Back Pain
For pain relief, injections can be more effective than an oral medication because they deliver medication directly to the anatomic location that is generating the pain. Typically, a steroid medication is injected to deliver a powerful anti-inflammatory solution directly to the area that is the source of pain. Depending on the type of injection, some forms of low back pain relief may be long lasting and some may be only temporary.
Injections to Diagnose Causes of Back Pain
Diagnostically, injections can be used to help determine which structure in the back is generating pain. If lidocaine or similar numbing medication is used, and the patient feels temporary relief after an anatomic region is injected (e.g. facet joint or sacroiliac joint), it can then be inferred that the specific region is the source of the pain. When considered in conjunction with a patient's history, physical exam, and imaging studies, injections used for diagnostic purposes can be very helpful in guiding further treatment for the patient.
This procedure is indicated for treatment of arm or leg pain due to pinched nerves in the neck or low back. Sometimes chronic neck or low back pain responds to it. At times it is performed in the thoracic spine. 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).
Overall success rate in terms of giving some relief is about 50%. The benefit from the procedure may last a few days, weeks, or many months. It helps patients deal with the pain while their own body is recovering from the cause of the radicular pain such as disc herniation or spinal stenosis.
The procedure may be performed up to three times a year. Side effects include aggravation of diabetes, infection, scarring of the nerves, and rarely avascular necrosis of the hip joints causing permanent arthritis in the hips. Other risks include nerve injury, dural tear causing persistent spinal headache, and very rarely paralysis if epidural hemtoma occurs.
Usually radiologic control such as C arm fluoroscopy is used for insertion of the needle. Radiographic dye is injected to make sure that the needle is in the epidural space. A mixture of local anesthetic and steroids is injected. Potential complications include permanent irreversible painful scarring of the nerve roots called Arachnoditis and spinal headaches and infection called epidural abscess. Paralysis can occur if patient is taking blood thinners such as Coumadin or aspirin and it is absolutely important that patients stop taking all types of blood thinners at least one week prior to the procedure.
Patients need to bring a driver with them to the procedure as they are not allowed to drive home by themselves after the procedure.
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
Epidural injections are done under sterile conditions very similar to surgery. Still, anytime a needle is inserted into the body there is a small chance of infection. Since the needle in an epidural is going near the spine, an infection is much more serious if it occurs. The chance that an infection will occur is extremely small.
An epidural injection can result in a hematoma. A hematoma is simply a collection of blood due to an injury to a blood vessel. An epidural hematoma can be serious if it is big enough to cause enough pressure on the spinal nerves so that they quit working. This can cause problems with the bowels and bladder.
Because the epidural injection actually paralyzes the nerves to the bowel and bladder for a short period, you may not have control over your bladder for one to two hours.
There is always a small risk of damage to the spinal nerves. The spinal cord is a bundle of millions of nerves that connects the brain with the rest of the body. If the epidural needle directly injures the spinal nerves, this can cause serious neurologic problems.
A trigger point injection is an outpatient procedure designed to reduce or relieve the back pain caused by trigger points. These small knots can form in muscles or in the fascia tissue leading to myofascial pain.
A sacroiliac (SI) joint injection—also called a sacroiliac joint block—is primarily used either to diagnose or treat low back pain and/or sciatica symptoms associated with sacroiliac joint dysfunction.
The sacroiliac joints lie next to the spine and connect the sacrum with the hip on both sides. There are two sacroiliac joints, one on the right and one on the left. Joint inflammation and/or dysfunction in this area can cause pain. Read more about Sacroiliac Joint Dysfunction.
The purpose of a sacroiliac joint injection is two-fold: to diagnose the source of a patient's pain, and to provide therapeutic pain relief. At times, these are separated and a patient will undergo a purely diagnostic or therapeutic injection, although often the two are combined into one injection.
A diagnostic SI joint injection is used to confirm a suspected diagnosis of sacroiliac joint dysfunction. This is done by numbing the sacroiliac joint with local anesthetic (e.g. lidocaine). The injection is performed under fluoroscopy (X-ray guidance) for accuracy. Once the needle has entered the sacroiliac joint, contrast is injected into the joint to ensure proper needle placement and proper spread of medication. The numbing medication is then injected into the joint.
After the numbing medication is injected, the patient is asked to try and reproduce the pain by performing normally painful activities. If the patient experiences 75-80% pain relief for the normal duration of the anesthetic, a tentative diagnosis of SI joint dysfunction is made. A second diagnostic sacroiliac injection should be performed using a different numbing medication (e.g. Bupivicaine) in order to confirm the diagnosis.
If this second diagnostic injection also provides 75-80% pain relief for the duration of the anesthetic, there is a reasonable degree of medical certainty the sacroiliac joint is the source of the patient's pain.
Some practitioners are performing lateral branch blocks to diagnose SI joint pain. The lateral branch nerves are small nerves that branch off the sacral spinal nerves and provide sensation to the joint. A lateral branch block might be performed to determine if a patient is a candidate for a radiofrequency nerve ablation to provide longer lasting relief of the pain associated with SI joint dysfunction.
A therapeutic SI joint injection is done to provide relief of the pain associated with sacroiliac joint dysfunction. The injection is performed using the same technique as a diagnostic SI joint injection, except that anti-inflammatory medication (corticosteroid) is included in the injection to provide pain relief by reducing inflammation within the joint.
If the patient experiences prolonged pain relief after a therapeutic sacroiliac joint injection, he or she can begin a physical therapy and rehabilitation program to further reduce pain and return the patient to normal activity levels.
If the therapeutic sacroiliac joint injection is successful in reducing or eliminating the patient's pain for a longer duration, it may be repeated up to three times per year, in conjunction with physical therapy and rehabilitation program, to help the patient maintain normal function.
This procedure is performed for treatment of chronic low back pain that has not responded to conservative measures such as prolonged physical therapy and activity modifications. A trial injection called facet nerve injection is performed 1st at another setting. Facet nerve injection anesthetizes those points between the junction of transverse process and the pedicle where tiny nerves that are known cause of low back pain reside.
If patient receives excellent response to the facet nerve injection then the more permanent radiofrequency facet block is performed. The procedure is performed with patient awake using x ray control called fluoroscopy. Stimulation is performed prior to actual coagulation and this makes the procedure quite safe in terms of nerve injury even though this can still occur. Nerve injury is quite rare. The tip of the radiofrequency needle gets hot coagulating or denaturing the tiny nerve fibers that are the known causes of chronic low back pain. Sometimes the tiny nerve fibers grow back causing recurrent low back pain and some patients require yearly facet blocks if they receive excellent response after each one. Other risks of the procedure includes infection and allergic reactions to medications used.
The overall clinical success rate of the procedure is about 50% in those who has excellent response to trial local anesthetic injection. The procedure takes approximately half an hour and patients are not allowed to drive home so that they need to bring a driver.
Mild analgesics are prescribed such as Vicodin for a few days afterwards as they will be in some pain from the procedure itself. Return to work without any restriction is possible usually in a few days after the procedure. Whether the procedure is successful or not is not determined until about a few weeks after the procedure when the pain from the procedure itself goes away.
Indications to use a facet joint injection
A facet joint injection is perhaps the best way to diagnose facet joint syndrome. Joints that may look abnormal on an X-ray may in fact be painless, and joints that look fine may indeed be the source of the pain; only the injection tells the true story. These injections may be used to treat low back pain and determine whether the facet joints are the true culprits. It is also a rather simple procedure with low risk.
This procedure is performed to further evaluate and treat ongoing arm pain or leg pain.
Patients usually have had a MRI scan or CT scans which determined the anatomic cause of their pain. The procedure is used to confirm the presumed source of the pain to pinpoint it and confirm it. This makes the diagnosis more accurate and increases the success rate of spine surgery if it is indicated.
Local anesthetic and steroids are injected together along the nerve root sheath that contains the nerve root. The nerve root is identified either via temporary pain reproduction as the needle tip hits the nerve or by radiographic dye injection along the nerve root sheath. The nerve root is "numbed up" on temporary basis for a few hours and it is critical during this time for the patient to document whether their arm or leg pain is greatly relieved. If there is excellent temporary relief of the pain during the 1st few hours after the injection it indicates that pinching of that particular nerve is cause of their arm or leg pain. It is not as important how they feel after the anesthetic wears off. The steroids that are injected can at times give a prolonged pain relief sometimes making need for surgery unnecessary. Therefore the injection has both diagnostic and therapeutic value.
Patients need to bring along a driver as they are not allowed to drive home. They can return to preinjection activities of daily living the next day. Risks of the procedure include infection, nerve injury, and aggravation of their original pain but these are quite rare.
In the upper lumbar spine and lower thoracic spine rarely complete paraplegia or paralysis can occur there is embolization of steroid particles into the main feed artery that supplies blood to the spinal cord. Similar situation in the cervical nerve root injection can result in permanent stroke or quadriplegia in very rare cases. These are very rare complications but they can be devastating.