An interlaminar epidural steroid injection (ILESI) is a non-surgical treatment for chronic pain originating from irritated or compressed nerves in the spine. When spinal structures like discs or bone spurs press against a nerve root, the resulting inflammation can cause radiating pain, numbness, or tingling in the arms or legs. This procedure delivers anti-inflammatory medication directly to the source of the problem, aiming to reduce swelling and alleviate symptoms. The relief provided allows patients to engage more fully in physical therapy and other rehabilitative treatments.
Defining the Interlaminar Approach and Its Purpose
The interlaminar approach is the specific route the physician uses to reach the spinal epidural space. This space is a protective, fat-filled cushion surrounding the dura mater, the outermost membrane encasing the spinal cord and nerve roots. The term “interlaminar” means the needle is directed through the gap between the bony arches, or laminae, of two adjacent vertebrae. This pathway requires the needle to pass through the ligamentum flavum to enter the posterior epidural space.
The injectate consists of a corticosteroid, an anti-inflammatory agent, mixed with a local anesthetic, such as lidocaine or bupivacaine. The steroid reduces swelling and inflammation, while the anesthetic provides immediate, temporary numbing relief.
ILESI treats radicular pain, which travels away from the spine along a nerve path. Indications include sciatica, often caused by a herniated disc, spinal stenosis, and degenerative disc disease. Because this method allows medication to spread over a broader area, it is often used when multiple nerve roots are the source of discomfort.
Preparation and Logistics Before the Procedure
Preparation for an ILESI focuses on minimizing the risk of bleeding. Patients must stop taking blood-thinning medications for a specific period before the appointment, including NSAIDs and prescription anticoagulants like warfarin, which require clearance from the prescribing physician. Patients are also often required to fast for four to eight hours prior to the injection, especially if intravenous sedation is planned, to prevent complications like aspiration.
Patients must provide a list of all current medications, including supplements and over-the-counter pain relievers, for the medical team to review. Arranging transportation home is required because the local anesthetic can cause temporary numbness or weakness in the limbs, making it unsafe to drive. A responsible adult must be present to drive the patient home immediately after the appointment.
Navigating the Injection Procedure
The injection is a precise, minimally invasive outpatient procedure performed by a physician in a sterile environment. The patient lies face down on a table, and the spinal area is cleansed with an antiseptic solution. The physician first administers a local anesthetic to numb the skin and underlying soft tissues at the injection site.
Safety and accuracy rely on fluoroscopy, a type of live X-ray guidance. The physician uses this imaging technology to guide a specialized needle through the interlaminar space and into the epidural space. Once positioned, a small amount of contrast dye is injected to create an “epidurogram,” confirming the needle tip is correctly placed and not in a blood vessel.
After confirming placement, the physician slowly injects the mixture of corticosteroid and local anesthetic, allowing the medication to bathe the irritated nerve roots. The entire process is usually completed in less than 30 minutes.
Immediate Recovery and Expected Outcomes
Following the injection, patients are monitored in a recovery area for 15 to 30 minutes to ensure there are no immediate adverse reactions. Temporary numbness or weakness in the limbs corresponding to the injection site is common due to the anesthetic, but this effect wears off completely within a few hours.
Immediate pain relief may occur from the local anesthetic, but this feeling is short-lived. Patients may notice a temporary increase in their original pain or mild soreness at the injection site for one to three days, sometimes called a “steroid flare-up,” as the anti-inflammatory medication begins working. The therapeutic effect of the corticosteroid begins within two to seven days, with the most significant relief peaking around one to two weeks following the procedure.
Patients should take it easy for the remainder of the day, avoiding strenuous activity, heavy lifting, or bending. Mild side effects can include temporary facial flushing, a warm sensation, or an elevation in blood sugar levels. Patients must contact their physician immediately if they experience signs of infection (fever, warmth, redness) or develop severe, unrelenting pain, or new weakness or numbness in their limbs.