Your shoulder nerve block Info Evidence
Last reviewed
Patients › Recovery
The nerve block we use for shoulder surgery — how it numbs your arm, why it controls pain so well, and what to expect as it wears off.
Almost all shoulder operations are done with a nerve block as well as a light general anaesthetic. The block is the single most effective thing we have for keeping you comfortable after surgery, and it is worth understanding what is planned so that none of it comes as a surprise.
What a nerve block is
All of the nerves that supply your arm pass through a tight bundle just above your collarbone. Using an ultrasound machine to see exactly where they lie, the anaesthetist places a small amount of local anaesthetic around that bundle. This is called a supraclavicular block. It switches off pain signals from the whole arm for several hours, long enough to cover your operation and the first part of your recovery, when pain would otherwise be at its worst.
You are not awake during the operation. You will usually have a light general anaesthetic on top of the block, so you sleep through the surgery. The block does the pain relief; the general anaesthetic keeps you comfortably asleep.
Why we use it for your shoulder
A good block does far more than a needle's worth of numbing:
- It controls pain better than tablets or a general anaesthetic alone. In study after study, patients who have a brachial plexus block have lower pain scores in the first hours after shoulder surgery and need much less strong painkiller. One review that pooled 36 separate trials and more than 3,000 patients having keyhole shoulder surgery found that brachial plexus blocks like this one both lowered pain scores and reduced the amount of strong opioid painkiller people needed afterwards.
- It lets us give a lighter general anaesthetic. Because the block is doing the heavy lifting on pain, you generally wake up clearer, with less grogginess and less nausea.
- It reduces how much opioid (strong painkiller) you need. That means fewer side effects (less constipation, drowsiness and nausea) and a smoother early recovery.
- It gets you comfortable, mobile and home sooner.
What it feels like
Within about 20–30 minutes of the injection, the arm becomes heavy, warm, numb and weak. You will not be able to lift it or feel much in it, and you may not be able to move your fingers. This is exactly what is meant to happen. The numbness usually lasts 8 to 18 hours, occasionally up to a day. It is completely temporary: full feeling and movement always come back.
Why you wear a sling
While the block is working, your arm is numb and has no power of its own. The sling is there to hold and protect it, so it cannot flop, dangle or get knocked, and so you do not lean or roll onto an arm you cannot feel. Keep it supported in the sling, keep it warm, and do not let it hang down. Think of it as looking after a limb that cannot yet look after itself.
Things you might notice (these are normal)
Because the nerves we numb sit close to a few others in the neck, you may notice some harmless temporary effects on that side:
- a droopy or heavy eyelid, and sometimes a slightly bloodshot eye
- a slightly hoarse voice or a stuffy-feeling nostril
- a sense that you can't take a completely full deep breath (the block can briefly quieten the nerve to the muscle under your lung on that side)
The supraclavicular approach we use is chosen partly because it tends to cause these effects less often than blocks placed higher up in the neck. They all wear off as the block does, and need no treatment.
When the block wears off — start your tablets early
This is the most important part to get right.
The block is excellent for the first 8–18 hours, and then sensation comes flooding back, often overnight. As it does, the pain can arrive quite suddenly. This is called rebound pain, and it catches people out because they felt so comfortable beforehand.
The trick is simple: don't wait for the pain. Take your regular prescribed pain tablets before the arm fully wakes up: we'll give you a rough idea of when that will be, and keep taking them regularly for the first couple of days, even while the arm is still numb. Patients who stay ahead of it have a far smoother first night. Patients who wait until the pain hits spend a miserable few hours catching up.
Call us, or seek help, if
- your breathing feels genuinely hard or is getting worse (a slight sense of not filling your lungs is expected; real struggle to breathe is not: get reviewed)
- your arm is still completely numb and floppy beyond about 24–30 hours
- your fingers turn white, cold or blue, or you get chest pain
For ordinary rebound pain as the block fades, take your tablets and stay ahead of it: it settles over the next day or two.
Evidence & references
Key Evidence
Brachial plexus blocks reduce pain and opioid use after shoulder surgery. Regional anaesthesia is the cornerstone of modern shoulder-surgery analgesia. A current review of regional techniques for shoulder surgery describes the supraclavicular brachial plexus block as an effective approach that provides dense analgesia of the arm while producing fewer of the unwanted neck-related effects (hoarseness, Horner's syndrome, diaphragm involvement) seen with higher interscalene blocks [1]. Across the broader literature, peripheral nerve blocks consistently lower early post-operative pain scores and reduce opioid consumption compared with general anaesthesia or local infiltration alone [2,3,5].
The benefit is largest in the first hours and translates into better recovery quality. A systematic review and meta-analysis in Anesthesiology found brachial plexus and suprascapular blocks deliver clinically meaningful analgesia for shoulder surgery, supporting their routine use [2]. A focused review of regional blocks for arthroscopic rotator cuff repair reached the same conclusion: blocks improve early pain control and reduce rescue-opioid requirements [3]. Longer-acting block formulations further extend the pain-free window after shoulder replacement [4].
Rebound pain is real and is best managed by pre-emptive oral analgesia. Because a single-shot block wears off after roughly 8–18 hours, patients can experience a sharp surge of pain as sensation returns — usually overnight. A two-centre randomised controlled trial and the wider rebound-pain literature emphasise that patient education and starting regular analgesia before the block resolves are central to a smooth recovery [6]. This is why patients are advised to begin their prescribed pain tablets early rather than waiting for pain to arrive.
References
- Zhang LL, Sinha SK, Murthi AM. Current Strategies in Regional Anesthesia for Shoulder Surgery. J Am Acad Orthop Surg. 2025;33(14):761-9. doi:10.5435/JAAOS-D-24-00738
- Hussain N, Goldar G, Ragina N, et al. Suprascapular and Interscalene Nerve Block for Shoulder Surgery: A Systematic Review and Meta-analysis. Anesthesiology. 2017;127(6):998-1013. doi:10.1097/ALN.0000000000001894
- Kim TY, Hwang JT. Regional nerve blocks for relieving postoperative pain in arthroscopic rotator cuff repair. Clin Shoulder Elb. 2022;25(4):339-46. doi:10.5397/cise.2022.01263
- Finkel KJ, Walker A, Maffeo-Mitchell CL, et al. Liposomal bupivacaine provides superior pain control compared to bupivacaine with adjuvants in interscalene block for total shoulder replacement: a prospective double-blinded, randomized controlled trial. J Shoulder Elbow Surg. 2024;33(7):1512-20. doi:10.1016/j.jse.2023.12.014
- Liu Z, Li YB, Wang JH, et al. Efficacy and adverse effects of peripheral nerve blocks and local infiltration anesthesia after arthroscopic shoulder surgery: A Bayesian network meta-analysis. Front Med (Lausanne). 2022;9:1032253. doi:10.3389/fmed.2022.1032253
- Uppal V, Barry G, Ke JXC, et al. Reducing rebound pain severity after arthroscopic shoulder surgery under general anesthesia and interscalene block: a two-centre randomized controlled trial of pre-emptive opioid treatment compared with placebo. Can J Anaesth. 2024;71(6):773-83. doi:10.1007/s12630-023-02594-0
