Controlled loss of sensation, that is usually temporary in nature is used extensively in medical science to induce pain relief in cases such as surgeries and labour. The word anaesthesia has been derived from its greek variant meaning ‘without sensation’.
Anaesthetic drugs can be introduced into the system in multiple ways. Two common methods of inducing blocks in the lower body are spinal block and epidural. Both methods induce numbing in specific regions, hence the patient is not completely sedated. Either way, the administration of anaesthesia should be done under the supervision of a licensed medical professional.
Epidural vs Spinal Block
The main difference between Epidural and Spinal Block is that epidural requires a catheter for carrying the anaesthetic, while spinal block can be given directly through a single injection in the cerebrospinal fluid. Hence in case of Epidural, the period of block can be extended.
Comparison Table Between Epidural and Spinal Block (in Tabular Form)
| Parameter of Comparison | Epidural | Spinal Block |
|---|---|---|
| Definition | Cather is adjusted in the epidural space so that drugs can be administered for an extended block | A single shot needle of drugs injected in the spinal region for a limited period of block. |
| Needle Used | A larger need is used for administration. | A relatively smaller needle is used to introduce a spinal block. |
| Delivery Frequency | Can be delivered multiple times through catheter | Can be delivered only once. |
| Site of Drug Injection | Drugs are injected in the epidural space. | Drugs are injected in the cerebrospinal fluid. |
| Local anaesthetic | A large amount of local anaesthetic is required. | A small amount of local anaesthetic is required. |
| Principle | Drug moves along the tissue | Drug moves through the fluid. |
What is Epidural?
Epidurals are anaesthetics used to induce blocks or pain-relief. Epidural is administered via catheters. A catheter is a small tube that is injected in the skin via a needle. Once the needle is removed the tube can be left there for the delivery of medication and drugs.
As explained by some patients an epidural induces period waves of a feeling of numbness. Epidurals are local anaesthetics hence the patient is usually conscious. This is because of the catheter for an epidural is placed outside the dura, in the epidural space. This means that drugs are allowed to move through tissue instead of fluid.
During the administration of an epidural, the dura might breach causing what is popularly called an epidural puncture. A large of local anaesthetic is used to make the process easy and pain-free. The anaesthetics relieve the burning sensation, however, a lot of patients feel the pressure of the needle pushing through. The needles used to administer an epidural are usually bigger.
It usually takes about 15v minutes for the epidural to work. A characteristic feature of an epidural is that it can be made to last to longer, as the quantity of drug entering the system can be adjusted. The drug quantity is increased to extend the period of block.
Epidurals are very commonly used to relieve labour pain in women. The amount of drug is adjusted according to the severity of the pain. It usually numbs the lower half of the body from the belly button to the lower legs. Common side effects of epidurals are lower blood pressure and headache.
What is Spinal Block?
A spinal block is also known as an intradural block. It is a form of anaesthetic that is given through the Cerebrospinal fluid. It is administered via a single needle fine needle. usually 9cm long. Needles used for a spinal block are usually smaller.
A spinal block is usually used for numbing the lower end of the body, for surgeries and other procedures. The needle punctures the dura, throwing the drugs inside the cerebrospinal fluid. Since the movement of drugs is easier and faster via fluid, only small amounts of anaesthetics are required.
Spinal anaesthetics are usually beneficial over complete sedation to avoid failed intubations. these are commonly used in orthopaedic surgeries, hysterectomy, nephrectomy etc. They are also very popular for caesarean and vaginal deliveries. Another benefit of using spinal anaesthesia during delivery is that the mother stays alert during the procedure.
Anatomically, a spinal block is used to inject the desired drug so that transmission of nerve signals is blocked. Moderate sedation is occasionally given to help the patient relax during the procedure. Surgeries can be done while the patient is wide awake.
The reason why the use of spinal block is limited to surgeries below the abdomen is that spinal block in upper regions can interfere with a person’s ability to breathe. It can cause conditions similar to lung paralysis.
A prior medical analysis is important before using a spinal block for numbing the body. Conditions under which spinal block might not be used include patients refusal, infection in the site of injection, bleeding disorders, increased intracranial pressure etc.
Although spinal blocks are very commonly used and are pretty safe if administered by a licensed medical professional. Minor complications include moderate hypotension, nausea etc. Major complications can be neural damage and death in extremely rare cases.
Main Differences Between Epidural and Spinal Block
- The main difference between Epidural and spinal block is that an epidural involves the transfer of anaesthetic drug with the use of a catheter while in a spinal block is given through a single injection.
- The size of the needle used in case of an epidural is larger than in spinal block.
- The period of block can be extended in case of epidurals as the quantity of drug can be adjusted, while Spinal blocks involve a single injection, hence block period is limited.
- Site of delivery is the epidural space in case of Epidurals, while in spinal blocks, cerebrospinal fluid is the target.
- Amount of local anaesthetic required is more for Epidurals, while spinal blocks require ver lessor no local or no anaesthetic.
Conclusion
Both Spinal Block and Epidurals are common methods of numbing the lower regions of the body, mainly below the abdomen. Spinal anaesthetics usually do not induce complete sedation, this means that the patient remains wide awake during the procedure, but does not feel the pain.
Spinal blocks are induced through one single injection, while epidurals require a catheter. Both methods have some side effects including headache and nausea. Both procedures are completely safe if administered by professional practitioners.
References
- https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1399-6576.1988.tb02689.x
- https://europepmc.org/abstract/med/8198262