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Section 12:
Nerve damage (3)
Risks associated with your anaesthetic
Section 12: Nerve damage associated
with peripheral nerve block
our anaesthetist may suggest that you have a peripheral nerve block. This
Y is an injection placed near to a nerve or group of nerves. Rarely, there may
be damage to nerves. This section gives you information about:
what a peripheral nerve block is how likely this is
how nerve damage can happen what recovery can be expected.
what the symptoms are
A peripheral nerve block is not the same as an epidural or spinal injection,
which are described in Section 11.
What is a peripheral nerve block? Risks and benefits
This is an injection of local anaesthetic Benefits of a nerve block may include a
near to the nerves which go to the area of shorter recovery period, and better pain
your operation, making the area feel relief after your operation. This allows
numb. It may be used on its own, as the you to be mobile more quickly after your
sole anaesthetic, or you may receive operation. You may not need as many
sedation or a general anaesthetic as well. strong pain relieving medicines such as
You can find out more about these choices morphine. This will help reduce your risk
in the booklet ‘Anaesthesia Explained’ of the side effects associated with these
which you will find on the Royal College medicines, which include nausea (feeling
of Anaesthetists website (www.rcoa.ac.uk). sick) and drowsiness.
This article describes nerve damage after
Types of nerve block
a peripheral nerve block. Your
There are many types of nerve block, anaesthetist will be able to tell you about
each one aimed at different groups of other risks.
nerves. Your anaesthetist will tell you if
there is a block suitable for your
Nerve damage
operation. Having talked about the
benefits, risks and your preferences, you Permanent nerve damage is a rare
can decide together whether you would complication of peripheral nerve block.1–4
like a nerve block. Nerve damage is usually temporary, and
most patients with nerve damage make a
How long does the block last? full recovery after a few days or weeks.
A nerve block can give pain relief for two
How does it feel to have nerve
to 18 hours depending on the site and on
the drugs used. Sometimes a catheter (a damage? What recovery can I
very thin tube) can be passed through the expect?
needle and left in place. More local Some people have mild changes in
anaesthetic can then be given for a longer sensation (feeling). There may be an area
period – perhaps up to a few days. of numbness or ‘pins and needles’.
1 Risks associated with your anaesthetic O Information for Patients: The Royal College of Anaesthetists
Section 12:
Nerve damage (3)
Sometimes there may be strange If you have the nerve block after you are
sensations or there may be pain. anaesthetised, the anaesthetist will take
Uncommonly, there may be weakness in other precautions to avoid nerve damage.
one or more muscles. He/she will be able to explain these to you.
Most nerve injuries are temporary, and Intra-neural injection (injecting drugs
will recover over a period of about three directly into the nerve rather than very
months. Permanent injury does occur on near to the nerve) can also cause nerve
rare occasions. In the most serious cases damage. This would cause feelings similar
there can be severe pain or permanent to those described above. The anaesthetist
paralysis of the area involved. may use a nerve stimulator (a small
electrical gadget which is connected to a
How does nerve damage happen? sticky pad on your skin and to the needle)
What is done to prevent nerve to help find the correct spot for injection
damage? and to help avoid intra-neural injection.
The ways in which a nerve can be damaged
are listed here, and explained below. Haematoma
Direct injury caused by the needle or This is a collection of blood near the
the catheter. nerve due to damage to a blood vessel by
Haematoma (a blood clot). the needle or the catheter. Small amounts
Inadequate blood supply. of bleeding or bruising are common, and
Infection. do not cause damage to nerves. A large
haematoma may press on a nerve and
Other causes.
cause damage. Rarely, an urgent
All anaesthetists performing nerve blocks
operation is required to remove the
are trained in the technique and will take
haematoma and stop it pressing on the
steps to prevent these types of nerve
nerve.
damage.
If you take blood-thinning medicines such
Direct injury as warfarin or clopidogrel, you are more
This may happen if the needle or catheter likely to get a haematoma. Your
damages the nerve. Contact with the anaesthetist will take this into account
nerve may cause ‘pins and needles’ or a before he/she offers you a nerve block.
brief shooting pain. This does not mean
the nerve is damaged but if the needle is Inadequate blood supply
not repositioned damage can occur. Every nerve is supplied by blood vessels,
If you are having a peripheral nerve block which keep it healthy. If the blood supply
and a general anaesthetic, your is damaged or reduced, the nerve may be
anaesthetist may wish to do the nerve starved of oxygen, which leads to damage.
block while you are awake, before giving
the general anaesthetic. This allows you Infections
to report any tingling or shooting pains These are very rare. They are slightly
that you feel. If you notice these, you more likely if a catheter is left in place.
should tell the anaesthetist immediately. Sterile conditions similar to those used for
The anaesthetist will reposition the the operation itself are used to help
needle and the feelings should disappear. prevent infection. If a catheter is used
2 Risks associated with your anaesthetic O Information for Patients: The Royal College of Anaesthetists
Section 12:
Nerve damage (3)
the site should be kept clean and checked further up the nerve. This shows
regularly by a nurse. If you have infection whether the nerve is working or not)
elsewhere or a weak immune system, you Magnetic Resonance Imaging (MRI)
are more likely to get an infection. The Computed Tomography (CT) scanning.
anaesthetist will take this into account The neurologist will suggest a treatment
before he/she offers you a nerve block. plan, which might include physiotherapy
and exercise. If you have pain, drugs that
What else can cause nerve damage?
relieve pain will be used. This may
If you have nerve damage, you should not include drugs that are normally used for
assume that it is caused by the nerve treating epilepsy or depression because of
block. The following list shows other the way that they change electrical
causes of nerve damage related to having activity in nerves. Drug treatment is not
an operation. You can find out more about always successful in relieving pain.
these causes in Section 10 in this series. Occasionally an operation can be done,
Your nerves can be damaged by the either to repair a nerve or to relieve
surgeon. During some operations, this pressure on a stretched nerve.
may be difficult or impossible to avoid.
If this is the case, your surgeon should How likely is permanent nerve
discuss it with you beforehand. damage?
The position that you are placed in for There have been many studies looking at
the operation can stretch a nerve and
how often nerve damage happens in
damage it.
various peripheral nerve blocks.1–4
The use of a tourniquet to reduce
blood loss during the operation will Symptoms lasting more than one week
press on the nerve and may damage it. happen in between 1 and 5 out of
every 100 nerve blocks (1–5%). The
Swelling in the area after the
risk varies between the different
operation can damage nerves.
blocks. The vast majority of those
Pre-existing medical conditions, such affected (92–97%), recover within
as diabetes or atherosclerosis four to six weeks. 99% of these people
(narrowing of your blood vessels), can have recovered within a year.
make damage more likely.
Permanent nerve damage is rare and
If I think I have nerve damage, what precise numbers are not available. A
possible estimate from the information
can be done about it?
that we do have suggests it might
Your anaesthetist or surgeon may arrange happen in between 1 in 5,000 and 1 in
for you to see a neurologist (a doctor 30,000 nerve blocks.
specialising in nerve diseases). Tests may
be done to try and find out exactly where Summary
and how the damage has occurred. This Permanent nerve damage after a
might involve: peripheral nerve block is rare. The most
nerve conduction studies (very small common type of nerve damage causes an
electrical currents are applied to the area of numb skin which is very likely to
skin or muscles and recordings made resolve within a few weeks.
3 Risks associated with your anaesthetic O Information for Patients: The Royal College of Anaesthetists
Section 12:
Nerve damage (3)
Authors References
Dr Sharmistha Saha, FRCA 1 Liguori GA. Complications of regional anesthesia.
Specialist Registrar in Anaesthetics Journal of Neurosurgical Anesthesiology
North Western Region 2004;16:84–86.
2 Ben-David B. Complications of peripheral nerve
Dr Justin Turner, FRCA blockade. Anesthesiology Clinics of North America
Lead Consultant Anaesthetist for Acute Pain 2002;20:457–469.
Hope Hospital, Salford
3 Fischer B. Complications of Regional Anaesthesia.
Anaesthesia and Intensive Care Medicine
Editor 2004;4:125–128.
Dr Barrie Fischer, FRCA 4 Auroy Y et al. Serious complications related to
Consultant Anaesthetist regional anesthesia. Anesthesiology
Alexandra Hospital, Redditch 1997;87:479–486.
President, European Society of Regional
Anaesthesia (GB&I zone) and ESRA Board
Member 1997–2004.
The Royal College of Anaesthetists
January 2006
The material from this article may be copied for the purpose of producing information materials for
patients. Please quote the RCoA as the source of the information. If you wish to use part of the
article in another publication, suitable acknowledgement must be given and the RCoA logo must be
removed. For more detailed enquiries about the use of this leaflet please contact:
The Royal College of Anaesthetists
website: www.rcoa.ac.uk
email: profstans@rcoa.ac.uk
The Royal College
of Anaesthetists This leaflet will be reviewed three years from the date of publication.
4 Risks associated with your anaesthetic O Information for Patients: The Royal College of Anaesthetists
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