An Epidural Steroid Injection (ESI) is a common medical procedure used to treat chronic pain in the back and legs, particularly pain caused by spinal nerve root irritation, often referred to as sciatica. This treatment involves injecting anti-inflammatory medication directly into the epidural space, the area surrounding the spinal cord and nerve roots. The regulatory status is complex: the procedure itself is not approved for this purpose, but the corticosteroid medications used within the injection are approved for other uses. This distinction between the approved drug and the unapproved application forms the basis of the procedure’s regulatory status.
Regulatory Status and Off-Label Use
The FDA’s regulatory authority focuses primarily on approving drugs and medical devices for specific indications, not on regulating the practice of medicine by licensed physicians. Once a medication receives initial FDA approval for one condition, a doctor is legally permitted to prescribe or use that drug for any other condition, which is a common practice known as “off-label use.” Physicians are free to use their medical judgment to prescribe approved drugs for unapproved applications when they believe it will benefit the patient.
Epidural Steroid Injections exist in a regulatory gray area because the procedure uses FDA-approved injectable corticosteroids in a location—the epidural space for back pain—that has not been formally approved by the agency. The FDA has stated that the effectiveness and safety of administering corticosteroids into the epidural space have not been established through their formal review process. Despite this lack of formal approval, ESIs are widely accepted and performed as a standard medical practice for treating radicular pain.
The FDA does not regulate the specific techniques or medical procedures performed by physicians, only the products themselves. This separation allows ESIs to be a legitimate, reimbursable part of pain management, even without an FDA-approved indication.
Medications Used in Epidural Steroid Injections
The medications administered in ESIs are corticosteroids, or glucocorticoids, which are powerful anti-inflammatory agents. Common injectable corticosteroids used include methylprednisolone, triamcinolone, betamethasone, and dexamethasone. These drugs are FDA-approved and considered safe when used for their labeled purposes, such as treating severe inflammation or injecting into large joints.
Particulate vs. Nonparticulate Steroids
A significant concern relates to the physical composition of the steroid formulation injected near the spinal cord. Some corticosteroids, such as methylprednisolone and triamcinolone, are known as “particulate steroids” because they contain microscopic solid particles suspended in the liquid. These particles are thought to pose a greater risk of blocking small blood vessels supplying the spinal cord if accidentally injected into an artery.
Dexamethasone is a “nonparticulate steroid” because it is a clear solution, and some medical experts suggest its use may carry a lower theoretical risk of vascular blockage. Additionally, the formulations of these drugs may contain preservative agents, such as benzyl alcohol, which have been investigated for potential neurotoxic effects when introduced into the delicate spinal environment.
Severe Risks Associated with Spinal Administration
In 2014, the FDA issued a Drug Safety Communication to warn the public and healthcare professionals about rare but serious neurological problems associated with the epidural injection of corticosteroids. This warning specifically addressed the risks of injecting these steroids into the epidural space for neck and back pain. The agency required drug manufacturers to add a warning to the labels of all injectable corticosteroids, describing these potential hazards.
The severe adverse events reported include spinal cord infarction (tissue death due to lack of blood supply), and subsequent complications such as paraplegia and quadriplegia. Other serious complications listed are stroke, cortical blindness, and death. These devastating outcomes are primarily linked to the accidental injection of the steroid into a blood vessel that supplies the spinal cord or brain.
If a steroid is mistakenly injected into one of the tiny arteries feeding the spinal cord, the drug or its particulate matter can cause a blockage, leading to ischemia, or lack of oxygen. The FDA emphasized that these events are rare, yet they are severe enough to warrant explicit discussion between the physician and the patient before the procedure. The agency’s warning served to ensure patients were fully aware of the potential for catastrophic harm.