How is an epidural nerve block performed?
An epidural nerve block is a procedure to block pain by injecting anesthetic medication into the epidural space of the spine. The procedure numbs the relevant nerve region thereby blocking the transmission of pain signals from those nerves to the brain. An epidural nerve block may be administered in the cervical, thoracic, lumbar or the caudal (lowermost) region of the spinal column.
The epidural space is the area between the inner wall of the backbone (vertebral column) and the outermost of the three membranes (dura mater) that surround and protect the spinal cord. The space between the inner two membranes is filled with cerebrospinal fluid that supplies nutrients to the spine and acts as a shock absorber.
An epidural nerve block may be performed to
- Induce loss of feeling (anesthesia) before a surgery
- Provide pain relief (analgesia)
An epidural nerve block is usually an outpatient procedure when performed as treatment for chronic pain. Steroids can also be administered to reduce inflammation. A pain management specialist performs the procedure that may take up to 30 minutes.
When an epidural nerve block is performed for anesthetic purposes during surgery or for pain relief post-surgery, the procedure will require hospitalization. Epidural nerve block may be the sole form of anesthesia or may be combined with general or spinal anesthesia (injection into the cerebrospinal fluid).
Prior to an epidural nerve block, the patient may be required to
- Undergo blood, urine and clinical tests for
- Undergo corrective treatments in case of certain conditions
- Undergo imaging tests such as ultrasonography and CT scan
- Stop taking antiplatelet medications and blood thinners a few days before, according to the doctor’s advice
The patient must
- Avoid eating or drinking eight hours prior
- Inform the doctor of any allergies
- Check with the doctor before taking any regular medications
- Depending on the level of the epidural, the patient sits upright, lies on their stomach, or lies on their side with the back arched to extend the spinal column.
- An IV line is attached to the patient for medication and fluids.
- Uses an antiseptic solution to sterilize the injection site in the relevant level of spine.
- Inserts the needle into the skin and administers a local anesthetic to numb the tissues under the skin.
- Inserts the spinal needle between two vertebrae in the midline of the spinal column or laterally, using ultrasonography and continuous X-ray (fluoroscopy) for guidance.
- Attaches the syringe to the needle and slowly advances it into the space between the vertebrae.
- Stops advancing the needle once the needle reaches the epidural space.
- Aspirates the syringe and checks there is no blood or cerebrospinal fluid to ensure the needle has not punctured a blood vessel or the spinal cord membrane.
- Sometimes injects a contrast medium to obtain images of the dye’s spread in the epidural space (epidurograph) to administer the medication in the most optimal place for pain relief.
- If it is a temporary procedure
- Injects the medication
- Withdraws the needle
- Arrests bleeding with pressure
- Places an adhesive tape over the injection site
- For continued administration of anesthetic medication
After the procedure
For an epidural nerve block for chronic pain management the patient can leave after being monitored briefly in the recovery room. If the epidural nerve block is administered as anesthesia for a surgical procedure the patient will require hospitalization accordingly.
How long does an epidural nerve block last?
The anesthetic effects of an epidural nerve block may last up to a day or more depending on the medication and dosage administered.
For chronic pain management steroids are usually administered to reduce inflammation and remove the pressure on the nerve roots. The anesthetic medication produces pain relief within 10 minutes, but the steroid may take two to five days to take effect.
In an epidural nerve block procedure, typically a series of three injections are administered two to three weeks apart. The effects of the epidural nerve block vary with individuals. Pain relief may last for months, or even permanently for some, but others may not find any relief.
What are the risks and complications of an epidural nerve block?
Epidural nerve block is a widely used procedure for anesthesia and analgesia. Potential complications may be procedure-related or drug-related:
- Soreness or bleeding at the injection site
- Infection at the injection site
- Air in the cranial cavity (pneumocephalus)
- Headache from dural puncture (postdural puncture headache)
- Sudden drop in blood pressure and heart rate (vasovagal syncope)
- Nerve damage
- Epidural or spinal hematoma leading to temporary or permanent disability
- Spinal epidural abscess
- Infection and sepsis
- Bacterial meningitis
- Cerebral hemorrhage
- Respiratory problems or failure
- Neurological problems such as tingling, numbness, muscle weakness or pain (neuropathy)
- Cardiac arrest and death
- Allergic reaction to the local anesthetic
- Local anesthetic systemic toxicity leading to causa equina syndrome with symptoms such as:
- Side effects of opioids such as:
- Side effects of steroids such as: