“I already had a cortisone injection.” I often hear this phrase from patients presenting to me at initial consultation in my practice as an interventional pain physician. When I ask what type of cortisone injection, I am often greeted with blank stares. Patients and even healthcare providers are relatively unaware of the vast array of interventional procedures used to treat chronic painful conditions. A clear understanding of the procedures performed by interventional pain physicians is essential to being an active participant in a patient’s recovery.
Cortisone is but one type of steroid that is used in injections used to treat painful conditions. However, many patients use cortisone injection as a synonym for epidural steroid injection. In reality, various steroids are used to inject inflamed joints, nerves, and soft tissues. There are three commonly performed types of epidural steroid injections: caudal epidural steroid injections, translaminar epidural steroid injections, and transforaminal epidural steroid injections. All of these injections should be performed with fluoroscopic guidance. A translaminar injection is often used when a patient has not had surgery and more than one nerve root or disc is involved and the interventionalist needs to spread the steroid across more than one level. A transforaminal injection targets a single nerve root or foramen. Additionally, a transforaminal injection allows access to the anterior epidural space, placing the medication, usually consisting of a steroid and local anesthetic closer to the inflamed area. In a caudal epidural injection, the needle is passed through the sacral hiatus. This type of injection is frequently performed in patients that have had prior back surgery. It is important that an interventionalist be comfortable in not only performing the various types of epidural steroid injections, but in selecting appropriate candidates for each type of injection.
Another common injection performed in an interventional pain clinic is called lumbar facet joint injections or medial branch blocks. These injections can be diagnostic or therapeutic. Facet injections are used to treat facet arthropathy or inflammation of the facet joints. The spine contains facet joints from the cervical and lumbar region. The joints frequently become inflamed or degenerated due trauma or the aging process. Pain from facet joints is often described as aching and aggravated with bending and twisting movements such as sweeping or vacuuming. The pain may travel into the hips and thighs but rarely travels below the knee. Inflammation or degeneration of the joints may or may not be visible on imaging, making an accurate history and physical examination imperative. Diagnostic facet blocks are generally performed by injecting several cc’s of a local anesthetic around or in the facet joints or medial branch nerves (the nerves that supply the facet joints). A positive test is achieved when a patient receives 50% or greater relief from their pain for the expected duration of the local anesthetic. A therapeutic injection includes steroids in an attempt to achieve longer pain relief.
When a positive result is achieved with facet blocks or medial branch blocks, many interventionalists will proceed with radiofrequency ablation (RFA). RFA is a procedure that uses heat transmitted through a needle to destroy the sensory nerve (medial branch nerve) to the facet joint. Great care is taken to avoid injury to a motor nerve and to properly identify the sensory nerve, both visually and electrically. Patients undergoing an RFA following a successful facet or medial branch injection can expect to achieve pain relief for 6 to 18 months, at which time the procedure can be repeated.
Sympathetic blocks are also frequently performed in an interventional pain clinic. These blocks are often used to treat complex regional pain syndrome (CRPS). Lumbar sympathetic blocks are used to treat sympathetically mediated pain or CRPS of the lower extremity and involve injecting local anesthetics around the sympathetic chain near the lumbar vertebral bodies under fluoroscopic or CT guidance. For CRPS involving the upper extremities stellate ganglion blocks are performed. The stellate ganglion is generally located at the level of a tubercle on the transverse process of C6. The sympathetic blocks are often repeated, initially as frequently as every few days, when attempting to control the symptoms and progression of CRPS. They are always performed in conjunction with physical therapy, arguably the most important treatment for CRPS.
Several other injections are often performed in an interventional pain practice including joint injections for joint pain and arthritis, trigger point injections for myofascial pain, and a variety of injections for abdominal and pelvic pain including celiac plexus blocks, and superior and inferior hypogastric nerve blocks along with a variety of peripheral nerve blocks. If all other treatments fail and a patient is not a surgical candidate, a select group of patients benefit from spinal cord stimulation or intrathecal pump implantation.
The interventional procedures at the disposal of a well trained and experienced interventional pain physician is extensive and often accelerate an injured patient’s recovery. It is important that all healthcare workers be aware of the various treatment options and available interventions. With proper patient and physician selection these procedures are often an integral part of recovery.