Anaesthesia stops you feeling pain and other sensations. It can be given in various ways:

  1. Local anesthesia involves injections which numb a small part of your body. You stay conscious but free from pain.

  2. Regional anesthesia involves injections which numb a larger or deeper part of the body. You stay conscious but free from pain. The most common regional anesthetic for Shoulder surgery is an Interscalene Block.

  3. General anesthesia gives a state of controlled unconsciousness. It is essential for some operations. You are unconscious and feel nothing.

We generally use a general anesthetic with either a local anesthetic or an interscalene block to ensure the best post-operative pain relief is achieved and you can go home earlier.

Your anesthetist will see you before your shoulder surgery and discuss your anesthetic with you. Please indicate any preferences and concerns then. If you would like to meet your anesthetist before the day of your operation, please let your orthopaedic surgeon know so it can be arranged for you.

Shoulder Surgery - Anaesthetic
Interscalene Block Anaesthetic

Interscalene Block

An Interscalene block (ISB) is a nerve block in the neck used to provide excellent pain relief for shoulder surgery carried out under general anesthesia. It numbs the main nerve bundles that affects the shoulder in the same way a dentist uses an injection to numb a tooth or part of your mouth.

The benefits of an interscalene nerve block (ISB) for shoulder surgery are:

  1. Reduced risk of nausea and vomiting and sedation

  2. Earlier to leave hospital

  3. Early intake of food and drink

  4. Excellent pain control

  5. Lighter general anesthetic with speedier recovery from the anesthetic

How an interscalene block works:

The anesthetist, Dr van den Berg and you need to decide collectively whether you are suitable for an ISB. You may not be suitable for an ISB if:

  • You have any problems with your diaphragm (muscle used in breathing) on the opposite side of surgery or any weakness or paralysis in the opposite arm to surgery

  • You are an elderly patient with severe breathing problems

You will usually already be under anesthetic before the ISB is done, although sometimes it is done whilst you are awake. If you have an ISB performed whilst you are awake, the anesthetist may give you some light sedation to help you to relax.

A special needle with a small electric pulse is used to locate the correct nerves. To judge the position of the injection, the anesthetist looks for muscle twitches in the arm. When the anesthetist is happy with the position of the needle, he or she injects some local anesthetic. The arm and shoulder soon become heavy and numb. The anesthetist will test the numbness of the arm before proceeding further.

What to expect after surgery ?

As your orthopaedic surgeon, Dr van den Berg will discuss your surgery details and what you can expect after surgery with you before you are admitted.


The main nerve block technique used in shoulder surgery is a single injection that lasts 12-24 hours. After leaving the hospital, it is extremely important that you take regular pain killers at the prescribed times from the moment of discharge. This is to avoid unpleasant pain at the time when the nerve block begins to wear off (which can be in the middle of the night). Pain killers will be prescribed by Dr van den Berg in the form of regular paracetamol and ibuprofen, and codeine if required (if there is no reason why you cannot take these pain killers).


Your orthopaedic surgeon will advised that you carry the “numb“ arm in an arm sling until normal sensation and motor function return. You should receive instructions about how to look after the shoulder and arm - it should be protected from heat or pressure injury and extremes of movement. You should take care not be come in contact with extremely hot or cold items because you will not be able to protect yourself from injuries of extremes of temperature.


Most side effects are related to the local anesthetic spreading and numbing the nerves adjacent to the ones that supply the shoulder and arm. Any or all the following can occur, but all resolve spontaneously as the effects of the local anesthetic wear off:

  • Shortness of breath - The injection in the neck can also numb half of the diaphragm (a muscle used in breathing). Some people can feel slightly short of breath, although in most this does not affect greatly the ability to breathe adequately.

  • Blurred vision (Horner’s syndrome) - 20%. This is seen as a drooping eyelid and slightly blurred vision on the side of the block and it is usually not a problem. Symptoms pass as the block wears off.

  • Hoarseness - 15%. Due to the nerves supplying the voice box being numbed. This improves as the local anesthetic wears off.

  • Difficulty swallowing water - 15%. Due to nerves supplying the voice box and throat being numbed. This effect can usually be overcome by “conscious“ swallowing and usually it is not a problem.


These are the result of the needle being inserted either in the wrong direction or too far. They are both extremely rare and easily dealt with, with little no aftereffects.

  • Punctured lung (pneumothorax) - Due to the needle piercing the lining of the lung causing it to collapse. If it occurs, admission to hospital while it resolves will be necessary. Very rarely a tube must be placed into the chest to drain the air.

  • Seizures and serious long-term nerve damage - less than 0.1% risk and reduced by carrying out the nerve block awake.

Fortunately, the serious side effects and complications are uncommon and are lessened by placement of block with use of a nerve stimulator.