What is Interscalene Brachial Plexus (ISB) block?
As well as a general anesthetic, your anesthetist may offer you a nerve block called interscalene brachial plexus block (ISB). The ISB is a regional anaesthetic technique used for surgeries of the shoulder and upper arm. It is a block that provides both safe and excellent surgical anaesthetic and postoperative pain relief. During this block, the anaesthetistinjects local anaesthetic solution around the major nerves in the interscalene groove supplying the shoulder and upper limb.
How is the block performed?
Once you are in the anaesthetic room you will be attached to the usual monitors, a blood pressure cuff, a light sensor to measure your blood oxygen level attached to your finger and ECG leads placed on your chest. You will receive some sedation through your intravenous cannula prior to placement of the block, which relaxes you and you will likely have little or no recollection of the block placement.
Once the nerves on the side of surgery are located using an ultrasound machine, the anaesthetist will numb the skin with local anaesthetic to make the procedure as comfortable as possible. Next a special insulated needle will slowly be inserted under ultrasound guidance and when the location is optimal the anaesthetist will inject long-acting anaesthetic solution to numb your shoulder and arm. The injection can take between 20 to 40 minutes to work. Your arm will feel heavy while the block is working.
What are the benefits of ISB?
The benefits of an interscalene nerve block (ISB) are:
Reduced risk of nausea and vomiting
Early intake of food and drink
Excellent pain control
Lighter general anaesthetic with speedy recovery from the anaesthetic
Earlier to leave hospital
What are the side effects of this block?
Hoarse voice - Rarely, your voice may be hoarse and you may feel like you are not taking a deep breath as you did before the surgery.
Change in facial features – Though temporary, you may experience a drop of the eyelid, slightly dilated pupils or numbness in the face on the same side as the block. These do not last beyond the duration of the block.
Shortness of breath - This is usually temporary, but it is important to sit up to allow your lungs to expand freely.
Altered sensation in the arm or hand - This may persist for some weeks, but usually, resolves on its own.
Nerve damage - occurs in less than 3 out of every 100 nerve blocks (3%). The vast majority of those affected (92-97%) recover within 4—6 weeks. 99% of these people have recovered within a year. Permanent nerve damage is very rare indeed (around 1.5 in 10 000 nerve blocks).
Punctured lung - and seizures are rarely reported complications of this block.
How long does this block last?
The numbness from the block usually lasts for 6-18hrs, occasionally up to 36hrs.
It is extremely important that you take regular painkillers at the prescribed times. This is to avoid unpleasant pain at the time when the nerve block begins to wear off. When the block starts to wear off you may feel pins and needles in your arm or hand, which gradually disappear.
Please contact your care team if the block has not fully worn off two days after your procedure.
Management of the numb arm
You should carry the numb arm in a sling until normal sensation and motor function returns.
Avoid direct heat, ice or pressure injury and extremes of movement onto the shoulder.
Try not to use any machinery or domestic appliances.
References
NYSORA (2022) Ultrasound-Guided Interscalene Brachial Plexus Nerve Block. Accessed 22 September 2022
RCOA (2020) Nerve blocks for surgery on the shoulder, arm and hand. Accessed 22 September 2022