Section 11: damage (2)

Risks associated with your anaesthetic Section 11: Nerve damage associated with a spinal or epidural injection

our anaesthetist may suggest that you have a spinal or epidural injection. These Yinjections can rarely be associated with nerve damage. This section gives you information about: 4 spinal and epidural injections 4 how likely this is 4 how nerve damage can happen 4 what recovery can be expected. 4 what the symptoms are

What is a spinal injection? An epidural is used for operations which A needle is inserted between the bones are longer than two hours or when pain of your back, through ligaments and relief is needed for several days. then through the dura. The dura is a You can find out more about having membrane which encloses the an epidural in the leaflets ‘Anaesthesia and spinal cord. Spinal injections are Explained’ and ‘Your epidural for usually performed near the lowest part pain relief’ on the Royal College of of the spine. At this level, the spinal cord Anaesthetists website (www.rcoa.ac.uk). itself has ended and a bundle of nerves is present which supplies the legs and Risks and benefits genital area. Nerves in this area are You can find general information about bathed in cerebro-spinal fluid (CSF). A the risks and benefits of spinal and single injection of local anaesthetic is epidural injections in the leaflets named given and the needle is removed. This above. Your anaesthetist will be able to injection makes you feel numb in the tell you more about your individual risks lower part of the body for about two and benefits. He/she will also be able to hours. describe alternative treatments, which will You can find out more about having a also have benefits and risks. spinal injection in the leaflets ‘Anaesthesia This article describes nerve damage Explained’ and ‘Your spinal anaesthetic’ on associated with spinal and epidural the Royal College of Anaesthetists website injections. It is aimed at patients having (www.rcoa.ac.uk). all kinds of operations. If you are planning to have an epidural or a spinal What is an epidural? for childbirth you can find additional A needle is used to introduce a fine information at www.oaa-anaes.ac.uk – catheter (tube) into your back. The Information for Mothers section. needle is passed between the bones, through ligaments and into a space What types of nerve damage can outside the dura. The catheter is passed happen? through the needle into this space and the Nerve damage is a rare complication of needle is removed. The catheter is taped spinal or epidural anaesthesia. Nerve securely to your skin. Local anaesthetic damage is usually temporary. Permanent can be given through this catheter for a nerve damage resulting in (loss period of time – perhaps several days. of the use of one or more limbs) is very

1 Risks associated with your anaesthetic v Information for Patients: The Royal College of Anaesthetists Section 11: Nerve damage (2) rare. More figures are given at the end of Most cases of direct damage are to a single this section.1–5 nerve and temporary. Injecting drugs 4 A single nerve or a group of nerves right into the nerve rather than into the may be damaged. Therefore the area area surrounding it can also cause direct affected may be small or large. damage. 4 In its mildest form you can get a small numb area or an area of ‘pins and Haematoma needles’ on your skin. This is a collection of blood near the 4 There may be areas of your body that nerve, which collects due to damage to a feel strange and painful. by the needle or the catheter. 4 Weakness may occur in one or more Small amounts of bleeding or bruising are muscles. common, and do not cause damage to the 4 The most severe (and very rare) cases nerve. A large haematoma may press on give permanent paralysis of one or a nerve or on the spinal cord and cause both legs () and/or loss of damage. Occasionally an urgent operation control of the bowel or bladder. is required to remove the haematoma and The majority of people make a full relieve the pressure. recovery over a period of time between If your blood does not clot normally or a few days and a few weeks. Permanent damage is very rare. you take a blood-thinning medicine (anti- coagulants) such as warfarin or heparin, How does nerve damage happen? you are more likely to get a haematoma. You will need to stop these medicines The ways in which nerve damage can be caused by a spinal or epidural injection before you can have an epidural or spinal are listed here and explained below. injection. It is important that you tell your anaesthetist about any problems with 4 Direct caused by the needle or blood clotting that you have had in the the catheter. past as you may not be able to have an 4 Haematoma (a blood clot). epidural or spinal injection. See below for 4 Infection. more details about anti-coagulants.6,7 4 Inadequate blood supply. 4 Other causes. Infection Most infections related to a spinal Direct injury injection or an epidural are local skin This can occur if the epidural or spinal infections and do not cause nerve damage. needle or the epidural catheter damages Very rarely, an infection can develop a single nerve, a group of nerves or the close to the spinal cord and major nerves. spinal cord. There may be an abscess (a collection of Contact with a nerve may cause ‘pins and pus) or meningitis. These infections are needles’ or a brief shooting pain. This very serious and require urgent treatment does not mean that the nerve is damaged, with antibiotics and/or surgery to prevent but if the needle is not repositioned, permanent nerve damage. damage can occur. If this happens you should try to remain still and tell your If you already have a significant infection anaesthetist about it. The anaesthetist elsewhere, or if you have a weak immune will change the position of the needle system, you have a higher risk of these and the sensations will usually improve serious infections. You may not be immediately. offered an epidural or spinal injection.

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Inadequate blood supply and spinal injections are trained in Low blood pressure is very common when these techniques. you have an epidural or spinal injection. 4 Spinal injections are placed below the This can reduce the blood flow to nerves expected lower end of the spinal cord. and, rarely, this can cause nerve damage. This should prevent damage to the Anaesthetists are aware of this risk and spinal cord itself. use both drugs and intravenous fluid to 4 Spinal injections are usually performed prevent large drops in blood pressure. while you are awake or lightly sedated. If there is pain or tingling due to Other causes contact with a nerve, you will be able There have been cases of the wrong to warn the anaesthetist. drug being given in an epidural or spinal 4 Your anaesthetist may wish to do injection. This is an exceptionally rare your epidural injection while you are event. awake. Direct after an epidural injection is rare, and so there What else can cause nerve damage? is no clear evidence about whether it is If you have nerve damage, you should not safer to do the epidural while you are assume that it is caused by the epidural or awake or after the general anaesthetic spinal injection. The following list shows has been given. Anaesthetists vary other causes of nerve damage related to in their views on this matter and you having an operation. You can find more should discuss your preference about about these causes in Section 10 in this this with your anaesthetist. series. Haematoma 4 Your nerves can be damaged by the surgeon. During some operations, this 4 If you take an anti-coagulant (a may be difficult or impossible to avoid. drug which thins the blood, such as If this is the case, your surgeon should warfarin), you will be asked to stop it discuss it with you beforehand. several days before surgery IF your 4 The position that you are placed in for doctors think it is safe to do so. The the operation can stretch a nerve and anaesthetist and surgeon together will damage it. decide if and when the drug should be 5 4 The use of a tourniquet to reduce stopped. A blood test will allow your blood loss during the operation will anaesthetist to decide if it is safe to press on the nerve and may damage it. have a spinal or epidural injection. If 4 Swelling in the area after the operation your anti-coagulation cannot be safely can damage nerves. stopped, then you will not be able to have an epidural or spinal injection. 4 Pre-existing medical conditions, such as diabetes or atherosclerosis 4 If you take aspirin, you can have an (narrowing of your blood vessels), can epidural or spinal injection. However, make damage more likely. your surgeon may ask you to stop taking the aspirin to help prevent What is done to prevent nerve bleeding during or after the operation. damage? Infection Anaesthetists are trained to be aware of nerve damage. Steps taken to prevent All epidural and spinal injections are each kind of damage are described here. performed under sterile conditions, similar to those used during the operation. Direct injury Your back should be kept clean and 4 All anaesthetists performing epidural regularly checked over the next few days.

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General care report describes the risks and benefits of If you have an epidural or spinal injection, these injections in great detail and gives the nurses will make regular checks until specific information on the risk of nerve everything returns to normal. This should damage. The number of people known help spot possible nerve damage very to have nerve damage is very small. The early and if treatment is needed it can be following figures are a guide: started immediately. Estimated frequency (cases per spinal/ epidural injection): If I think I have nerve damage, what can be done about it? The risk of damage to nerves is between 1 in 1,000 and 1 in 100,000. Your anaesthetist or surgeon may arrange for you to see a neurologist (a doctor In many of these cases the symptoms specialising in nerve diseases). Tests may improve or resolve within a few weeks or be done to try and find out exactly where months. and how the damage has occurred. This The risk of longer lasting problems is might involve: 4 Permanent harm 4 nerve conduction studies (very small 1 in 23,500 to 50,500 electrical currents are applied to the 4 Paraplegia or death skin or muscles and recordings made 1 in 54,500 to 1 in 141,500 further up the nerve. This shows whether the nerve is working or not) Summary 4 Magnetic Resonance Imaging (MRI) Nerve damage is a rare complication of 4 Computed Tomography (CT) scanning. spinal or epidural injection. The neurologist will suggest a treatment In the majority of cases, a single nerve is plan, which might include physiotherapy affected, giving a numb area on the skin and exercise. If you have pain, drugs or limited muscle weakness. These effects that relieve pain will be used. This may are usually temporary with full recovery include drugs that are normally used for occurring within days or a few weeks. treating epilepsy or depression because Significant permanent nerve damage of the way that they change electrical resulting in the loss of the use of your legs activity in nerves. Drug treatment is not is very rare. always successful in relieving pain. Some people have a higher risk of Occasionally an operation can be done, permanent damage. Your anaesthetist either to repair a nerve or to relieve will balance this against the benefits of an pressure on a stretched nerve. epidural or spinal injection. Your anaesthetist will be able to tell How likely is permanent nerve you about the benefits and risks of an damage? epidural or spinal injection for you as an A large national audit of major individual. He/she will also be able to complications from spinal or epidural describe the alternatives. injections performed in the UK was published in 2009 by the Royal College of Anaesthetists and is available on the College website.4 The audit estimated that just over 700,000 central nerve blocks are done each year in the UK in NHS hospitals. 45% are epidural injections and about 40% are spinal injections. The

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Authors References Dr Stephen Wiggans, FRCA 1 Wheatley RG, Schug SA, Watson D. Safety and Specialist Registrar in Anaesthesia efficacy of postoperative epidural analgesia. Br J North Western Region Anaesth 2001;87:47–61. 2 Auroy Y, et al. Serious complications related to Dr Justin Turner, FRCA regional anesthesia. Anesthesiology 1997;87:479– Lead Consultant Anaesthetist for Acute Pain 486. Hope Hospital, Salford 3 Horlocker T, Wedel D. Neurological complications of spinal and epidural anesthesia. Reg Anesth Pain Editor Med Jan–Feb 2000;25(1):83–98. Dr Barrie Fischer, FRCA 4 Cook TM, Counsell D, Wildsmith JAW. Major Consultant Anaesthetist complications of central neuraxial block: report Alexandra Hospital, Redditch on the Third National Audit Project of the Royal College of Anaesthetists. Br J Anaesth 2009;102(2): President, European Society of Regional 179–190. Anaesthesia (GB&I zone) and ESRA Board 5 de Seze MP et al. Severe and long-lasting Member 1997–2004. complications of the nerve root and spinal cord after central neuraxial blockade. Anesth Analg 2007;104:975–979. 6 Bombeli T, Spahn DR. Updates in perioperative coagulation. Br J Anaesth 2004;93:275–287. 7 www.asra.com. Second consensus statement on neuraxial blockade and anti-coagulation: 2002.

The Royal College of Anaesthetists Revised edition 2009 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 information or enquiries about the use of this leaflet please contact: The Royal College of Anaesthetists website: www.rcoa.ac.uk email: [email protected] The Royal College of Anaesthetists This leaflet will be reviewed three years from the date of publication.

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