Epidural Steroid Injections (ESIs) are a common, non-surgical treatment designed to alleviate radicular back and leg pain caused by nerve root inflammation or compression. The procedure involves injecting a corticosteroid and a local anesthetic into the epidural space of the spine, where the irritated spinal nerves are located. The goal of the steroid is to reduce inflammation, which diminishes the pain signals traveling from the compressed nerve. While often effective, many patients experience little or no sustained relief, signaling a need to re-evaluate the underlying cause of the pain.
Identifying Why the Injection Failed
The failure of an ESI to provide lasting relief can be attributed to the procedure’s mechanics, the accuracy of the initial diagnosis, or the nature of the underlying spinal condition. Even when performed using fluoroscopic guidance, technical factors like suboptimal needle placement or limited spread of the injectate can prevent the anti-inflammatory medication from adequately reaching the affected nerve root.
The most common reason for failure relates to the source of the pain not being the target of the injection. ESIs are designed specifically to treat radiculopathy—pain originating from an irritated spinal nerve root, typically due to a herniated disc or spinal stenosis. If the primary pain comes from a non-radicular structure, such as the facet joints, the sacroiliac (SI) joint, or muscular strain, the epidural injection will have little effect.
The underlying pathology may also be too severe or complex for an anti-inflammatory injection to overcome. Conditions like severe lumbar spinal stenosis (LSS) involve anatomical changes that cause mechanical compression of the nerves. Reducing inflammation is only a temporary fix that does not address the structural narrowing. Furthermore, scar tissue (epidural fibrosis) can prevent the injected medication from spreading to the target nerve.
Diagnostic Steps Following Lack of Relief
When an initial ESI fails to provide satisfactory pain relief, the clinical process shifts to a thorough re-evaluation of the patient’s condition. The physician conducts a comprehensive physical examination and reviews the patient’s pain history to determine if the symptoms have changed or if the initial diagnosis needs adjustment. This step helps recognize factors associated with a higher risk of treatment failure, such as prolonged pain duration or a non-radicular diagnosis.
The next phase often involves advanced imaging to look for structural issues that may have been underestimated or missed. A higher-resolution Magnetic Resonance Imaging (MRI) or a Computed Tomography (CT) myelogram may be ordered. This imaging clarifies the severity of nerve compression, the size of disc fragments, or the extent of spinal canal narrowing, confirming if the structural problem is too extensive for an injection to be successful.
A particularly useful diagnostic tool following ESI failure is the use of highly specific, localized anesthetic injections. These targeted diagnostic blocks, such as medial branch blocks or sacroiliac joint injections, isolate the precise source of the pain. By injecting a local anesthetic near a specific nerve or joint, the physician can confirm if the facet joints or the SI joint are the true pain generators, effectively ruling out radiculopathy as the primary cause.
Next Steps in Treatment Alternatives
Once the diagnosis is refined following the failure of an ESI, a new treatment plan is developed, often starting with the least invasive options. A highly specialized physical therapy program can be beneficial, focusing on specific exercises like the McKenzie method to manage disc-related pain, or aquatic therapy for patients with severe limitations. Medication management may also be adjusted to include nerve-specific drugs, such as gabapentin or pregabalin, which better address neuropathic pain signals originating from an irritated nerve.
If conservative measures remain ineffective, the next step involves considering other minimally invasive procedures that target different pain sources. For confirmed facet joint pain, Radiofrequency Ablation (RFA) uses heat energy to temporarily disable the nerves sending pain signals from the joint. Patients with chronic leg pain, especially those with severe spinal stenosis, may be candidates for procedures like the mild (minimally invasive lumbar decompression) procedure, which removes small pieces of thickened ligament to relieve mechanical pressure on the nerves.
When all conservative and minimally invasive interventional options have been exhausted, or if the structural pathology is too severe, a surgical consultation becomes necessary. Surgical decompression procedures, such as a laminectomy or a microdiscectomy, address the root cause by physically removing the material compressing the nerve or spinal cord. In cases of spinal instability or severe degenerative changes, a spinal fusion may be discussed to stabilize the affected spinal segments, offering a definitive structural solution.