Lumbar injections, also called epidural injections, are frequently used to help relieve persistent low back pain, sciatica and cruralgia. More and more precise thanks to the guidance of medical imagery, their effectiveness is however inconsistent.

Lumbar infiltration consists of locally injecting a low dose of an anti-inflammatory treatment, most often based on cortisone, in order to locally reduce the inflammation, and thus the pain. The infiltration makes it possible to deliver to the painful site even a powerful anti-inflammatory with a very low general diffusion, which allows a better efficiency while avoiding the side effects of anti-inflammatory treatments.

The injection is made in the spine, in the epidural space at the level of the nerve root concerned, where the nerve leaves the spine. The product can be injected at the interlaminar, caudal or transforaminal level, depending on the release of the drug desired.

Infiltration is performed on an outpatient basis, today most often under radiological, ultrasound or CT guidance in order to choose the right entry point for the needle and follow its path.

During CT-guided lumbar infiltration, the patient lies on his stomach on the scanner table. A first scan is performed in order to accurately locate the injection site. On cleansed and sanitized skin, after local anesthesia, the radiologist first injects an iodinated contrast product to check that the drug is spreading well in the desired area. Then, he injects the anti-inflammatory treatment.

The infiltration is proposed as a second indication in patients suffering for several weeks, not calmed by rest and drug treatments, in acute period of low back pain, sciatica or cruralgia related to a herniated disc or a narrow lumbar canal.

The patient is usually kept for a short period of monitoring after the examination. During the hours following the infiltration, it is not uncommon for the pain to increase.

A rest of 24 to 48 hours is recommended so that the product maintains its maximum concentration in the painful area, and acts without diffusing.

The results

Improvement is usually seen within 24 to 48 hours, but efficacy is inconsistent. It is highly dependent on the patient. Two to three injections a week apart are sometimes necessary to obtain an action on the pain.

In addition, the infiltration does not treat the cause of the pain. It is therefore often an adjunct treatment in the acute phase, before resorting to surgery.

The risks

As with any injection, there is a very low risk of infection. The days following the infiltration, any sign of infection (fever, inflammation at the injection site) should therefore lead to a consultation.