Differences Between an Epidural and a Spinal Block

Universally among species, pain is recognized as a biological alarm indicating that the body is threatened, under stress, or injured. The sensation of pain acts as a protective mechanism that typically subsides when the stimulus is removed or when the body is healed. At other times, the ‘alarm’ can be reduced with the proper use of analgesics or, in cases dealing with medical emergencies or procedures, can be temporarily silenced altogether with anesthetics administered by licensed medical professionals.

A number of medical procedures require the use of anesthetics, the main purpose of which is to inhibit the transmission of signals sent from affected nerve cells to pain receptors in the brain. There are a few different types of anesthesia. There’s regional anesthesia where only a portion of the body is affected, and general anesthesia where the person ‘goes to sleep’ (loses consciousness) and feels no pain at all. Lastly, there is a kind of anesthesia called a ‘local’ where only a minute portion of the body is desensitized during minor surgery such as closing small wounds with stitches, for example, or for some oral dentistry procedures.

Epidurals and spinal blocks are both regional anesthetic procedures which are commonly confused because they are seemingly very similar. Generally, the term ‘epidural’ refers to a procedure requiring an aesthetician to inject opiates into the spinal column along the cervical (neck), thoracic, or lumbar sites for the purposes of: 1) reducing pain (analgesia); or 2) causing numbness and partial or temporary paralysis of the lower limbs (anesthesia). Epidural anesthesia’”the latter of the two descriptions’”most resembles a spinal block; however, these are two separate procedures that cause very different results. Many surgeries are performed using epidural anesthesia, including orthopedic surgeries on the pelvis, legs and ankles; hernia; nephrectomy (kidney removal); and lower-limb trauma to list a few.

Epidural anesthesia which is also known as an ‘epidural block’ is performed to minimize pain, allowing for measured mobility (limited use of muscles) in the affected area. Epidural anesthesia minimizes sensation to specific regions of the body and is commonly offered to pregnant women before or during labor. Should a mother-to-be decide to have a painless delivery, a catheter is inserted into her spine, entering into the outermost part of the spinal canal called the ‘epidural space.’ The catheter serves as a route for anesthetics to enter the body, thus blocking the sensations from traveling to pain receptors in the brain. Larger doses of anesthetics are used during an epidural compared to dosing during a spinal block procedure, the effects being realized in as little as 15 ‘“ 30 minutes. The use of a catheter also allows for additional dosing post-operatively or during the procedure.

By comparison, spinal anesthesia which is also called a ‘sub-arachnoid block’ or ‘spinal block’ is another form of regional anesthesia. Differences lie in the administration of the process which uses a single injection of a local anesthetic into the area of the spinal column called the ‘sub-arachnoid space.’ Spinal blocks also differ from epidural anesthesia in that the required amount of opiate used is much less during a spinal block procedure. The rate of onset is quicker: it only takes 5 minutes for the anesthesia to take effect. Spinal blocks require the injection site to be below lumbar vertebra 2 (L2-L3; L3-L4) to avoid piercing the spinal cord. Spinal blocks are more likely to be used to induce temporary, regional paralysis of limbs and complete numbness in the affected area.

Summary:

1. Anesthesia is commonly used during medical procedures. The three types of anesthesia are general, regional and local.
2. Epidural and spinal anesthesia are seemingly similar forms of procedural anesthesia but they are different in a number of ways.
3. Epidural anesthesia (epidural block) requires the use of a catheter which is inserted into the epidural space, while spinal anesthesia (spinal block) uses a single injection into regions of the spine below the lumbar vertebra 2 to avoid piercing the spinal cord.
4. The quantity of anesthetic agent for epidural block is much more than what is required for spinal anesthesia.
5. The location where an epidural block can be administered is in the lumbar, cervical or thoracic regions of the spine, while spinal anesthesia can only be administered below L2.