An epidural is a form of regional analgesia where medication is delivered near the spinal nerves to block pain signals from traveling to the brain. The procedure involves injecting a local anesthetic and often an opioid into the epidural space, which is a small area just outside the membrane protecting the spinal cord. While the primary purpose is pain relief, especially during childbirth, the placement process involves a distinct series of sensations.
Preparation and Positioning for Placement
Before the procedure begins, the anesthesiologist will ask the patient to assume a specific position that maximizes the space between the vertebrae in the lower back. This typically involves sitting up and curving the back outward, often by tucking the chin to the chest and rounding the shoulders forward. A nurse or support person will help the patient maintain this still, curved position, which is necessary for accurate needle placement.
The lower back area is then thoroughly cleaned with an antiseptic solution to prevent infection. This cleaning solution, often containing chlorhexidine, is distinctly cold and wet against the skin. The anesthesiologist will then locate the precise insertion point, often using their fingers to feel for the bony landmarks of the spine before proceeding with the injection.
The Sensation of Local Anesthetic Injection
The first injection involves a very fine needle used to deliver a local anesthetic directly into the skin and surrounding tissue at the chosen insertion site. This initial injection is often the sharpest sensation experienced throughout the entire procedure. Patients typically describe this feeling as a quick, intense sting or a brief, sudden prick, similar to getting a blood draw or a flu shot.
As the numbing medication is pushed into the tissue, the sharp sting quickly transitions into a more profound sensation. This can feel like a brief burning or intense cold spreading under the skin, indicating the anesthetic is starting to work. This discomfort is very short-lived and is intended to completely numb the area for the subsequent placement of the larger epidural needle.
What the Epidural Needle and Catheter Placement Feels Like
Once the local anesthetic has taken effect, the area is sufficiently numb to proceed with the placement of the main epidural needle and catheter. The patient should not feel a sharp, cutting pain from the larger needle, as the deep tissue is now frozen. Instead, the sensation is described as a strong, deep pressure or a pushing feeling as the needle is advanced through the ligaments and into the epidural space.
It is imperative to remain motionless during this phase, as the anesthesiologist is navigating millimeter-sized spaces between the spinal vertebrae. Patients may occasionally feel a brief, electrical, or tingling sensation that shoots down one leg or hip, similar to hitting the “funny bone.” This is a transient feeling that occurs if the needle or the soft, thin catheter briefly brushes against a spinal nerve root during insertion.
The Onset and Resulting Sensation of Pain Relief
After the catheter is secured, a test dose and then the full dose of medication are administered, beginning the process of pain relief. Patients may notice a cold feeling spreading across their back or a wave of warmth in their lower body as the medication travels through the epidural space. The medication does not work instantly but typically begins to provide noticeable relief within 10 to 20 minutes, with the full effect taking up to 30 minutes.
The resulting sensation is often described as heaviness, warmth, or a deep dullness in the abdomen and lower extremities. While the sharp pain of contractions disappears, many patients still feel the sensation of pressure or tightening from the contracting uterus. This residual feeling of pressure, rather than pain, is a normal and often desirable effect, as it allows for an awareness of the body’s movements without the distress of the pain.