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Local anaesthetic for pain relief after surgery

What is local anaesthetic and how does it work?

Local anaesthetic is a medicine that aims to numb a specific area of the body. It works by blocking the nerves that are sending pain messages to the brain and wears off after several hours.

Why is local anaesthetic used for pain after surgery?

Local anaesthetic can be used as part of the plan to prevent pain during a general anaesthetic for some kinds of surgery and can reduce the amount of other strong pain-killing medicines needed. It also has the benefit of lasting long enough to help keep you comfortable while waking up and for some time afterwards.

Who decides if I can have local anaesthetic?

The anaesthetist and surgeon will explain if the use of local anaesthetic is appropriate and make the decision with you. There are some kinds of major surgery where we would strongly recommend the use of local anaesthetic as part of the plan for pain relief afterwards.

When is the local anaesthetic given?

At Sheffield Children’s Hospital, local anaesthetic for postoperative (after the operation) pain relief is usually given after the general anaesthetic has started so you are unaware of the procedure taking place. The picture below shows how local anaesthetic can numb a small or larger part of the body and last from a few hours to several days.

The anaesthetist will discuss the options with you on the day of surgery and you may be able to make a choice.

What are the ways local anaesthetic can be given?

Wound infiltration

  • One-off injection
  • Lasts 4 to 6 hours
  • Used in cases such as plastic surgery


  • An infusion catheter is placed in the space around the spinal cord, allowing local anaesthetic to numb a large area of the chest, tummy, pelvis or legs
  • Usually used for 48 hours and lasts up to 4 hours after the infusion has stopped
  • Often used for major chest or abdominal surgery, or orthopaedic surgery

Caudal epidural

  • One-off injection near to the base of the spinal cord to numb the nerves to the groin and legs. An infusion catheter is sometimes added in small babies
  • Lasts up to 18 hours
  • Often used in hernia surgery

Nerve block

  • One-off injection around a nerve to a part of the body
  • Lasts up to 8 hours
  • Often used in orthopaedic surgery

Nerve block with infusion

  • An infusion catheter is placed near large nerves to a part of the body
  • Usually used for 48 hours and lasts up to 4 hours after the infusion has stopped
  • Often used in orthopaedic surgery

Human body showing ways anaesthetic can be given, including nerve blocks, epidurals and wound infiltration

Who will look after me after the surgery?

The Pain Team along with ward doctors and nurses will all work together to monitor and observe you closely. They may also do sensory assessments using cold spray, to check feeling, and ask you to make small movements to show how your muscles are working.

What if it still hurts after surgery?

Occasionally local anaesthetic may not provide complete numbness and you may still feel pain. We may have to consider increasing or adding other medication.

What will it feel like when the local anaesthetic wears off?

Usually there is a bit of tingling before full sensation returns. There may be some soreness too when the area of surgery is no longer numb.

We usually give you other pain-relieving drugs before the local anaesthetic wears off to prevent discomfort. When you have been receiving a continuous infusion of local anaesthetic, you may need an increased dose of other medicines for a little while to ensure you stay comfortable as the numbness wears off. It does not hurt when the infusion catheter is removed.

Are there any side effects?


  • A tingly feeling or numbness around the site can be expected.
  • When larger nerves are blocked, there is usually some muscle weakness in the numb area too. Often the legs feel very heavy.
  • If an infusion catheter is being used, a little leaking is also common, which may look slightly blood-stained.

Less common

  • Infection at the site
  • Bleeding or bruising
  • Allergic reaction

Are there any alternatives?

If local anaesthetic is not appropriate, you can have oral pain relief medication and infusions of strong pain-relieving drugs such as morphine. Often these medicines are used alongside local anaesthetic techniques to provide several methods to control pain at the same time.

Is there anything else we should know?

Sometimes an anaesthetist may adjust the position of a local anaesthetic catheter after surgery if they feel that will improve the degree of numbness. It is not a painful procedure to have the catheter adjusted or removed.

More information about epidurals

When might an epidural be used?

Epidurals are used mainly for children having surgery to the chest, abdomen or legs, due to the high level of pain relief they provide. If the anaesthetist thinks an epidural will benefit you, they will explain the risks and benefits to you before the operation takes place.

The use of an epidural may reduce the amount of strong intravenous medicine, such as morphine, you need after the operation. This may allow you to be comfortable without some of the side effects of morphine, such as nausea, itching and drowsiness.

Are there any disadvantages of epidurals?

Sometimes epidurals may work better on one side of the body than the other, or not work well at all. The anaesthetist may be able to adjust the position of the infusion catheter to improve the numbness, or larger doses of other pain-relieving drugs may be needed. It is common for the legs to feel numb too, and to feel heavy due to muscle weakness.

Patients with an epidural usually need a urinary catheter while the epidural is running, as they may sometimes find it difficult to pass urine while numb and muscle weakness may limit movement. You will also need an intravenous drip of fluid while the epidural is running.

Are there any side effects of epidurals?

Epidurals can occasionally cause sickness or itching, and other drugs can be given to help with these problems if they occur. 

Key message for parents

Very rarely an infection can develop where the epidural catheter was inserted into the back. It is important that you seek urgent medical attention if your child develops any symptoms or signs of infection in the early days or weeks following discharge from hospital. These include swelling, redness, pain or pus at the insertion site, a high temperature, headache, lethargy, numbness, weakness or difficulty passing urine. The doctors looking after your child will need to know that your child had a recent epidural so they can organise the right tests and treatment.

Contact us

If you have any questions or concerns about local anaesthetics or postoperative pain options, please speak with the Pain Team on Monday to Friday between 8.30am until 5.30pm on 0114 271 7397.

Further resources

Please read our resource for more information about risks of anaesthetics.

Is something missing from this resource that you think should be included? Please let us know

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Please note: this is a generic information sheet relating to care at Sheffield Children’s NHS FT. These details may not reflect treatment at other hospitals. This information is not intended as a substitute for professional medical care. Always follow your healthcare professionals’ instructions. If this resource relates to medicines, please read it alongside the medicine manufacturer’s patient information leaflet. If this information has been translated into another language from English, efforts have been made to maintain accuracy, but there may still be some translation errors. If you are unsure about any of the guidance in this resource or have specific questions about how it relates to your child, always ask your healthcare professional for further advice.

Resource number: ANA8

Resource Type: Article

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