I work as a consultant Anaesthetist at Lewisham Hospital NHS trust, London.
My area of interest is orthopaedics, trauma and regional anaesthesia.
After graduating from medical school in 1996 I trained as an anaesthetist at Guys St thomas and associated hospitals during which I did a fellowship in regional Anaesthesia.
I am also the treasurer to the London Society of regional anaesthesia and also faculty to many of the regional courses run in the UK.
Comments a recent paper about the interscalene approaches
Respiratory impact of analgesic strategies for shoulder surgery.
Verelst P, van Zundert A.
Reg Anesth Pain Med. 2013 Jan-Feb;38(1):50-3
For a start, I agree with what the paper says based on evidence and also my experience of doing ISB block on respiratory compromised patients that phrenic nerve involvement is almost inevitable with an ISB. I am still to come across a technique of avoiding the phrenic nerve with an ISB regardless of the volume of anaesthetic used. recently i too have started using 3 mls of LA around C5 & C6 nerve roots with variable success. I agree its almost impossible to reliably avoid the phrenic nerve involvement in an ISB. In patients who have impaired respiratory function the choice of doing an interscalene block for shoulder surgeries have to be carefully considered against the potential risk of requiring respiratory support in the peri-operative period till such time the effects of the LA wane. There have been discussions of using short acting LA agents with the first injection of ISB to evaluate whether the patient can tolerate the phrenic nerve involvement, before subsequent injection through the catheter of a more long acting agent to provide post-operative pain relief. This approach does have the benefit that should the phrenic nerve involvement compromise respiratory function at least it will be a for a short duration, despite that I am still uncertain if this is the right approach. To conclude I agree that should there be any concerns of respiratory compromise ISB should be preferably avoided and the combination of spraclavicular and axillary block will provide alternative analgesia in the post-operative period.
GEORGE MATHEW MD
Interview with the expert
1- About the out of plane technique in the interscalene approach. Do you think it is safer?
Any approach is only as safe as the competence, knowledge and experience of the operator. My technique has always been to do most blocks in the in-plane approach and that is what i tend to teach my trainees too. There are some blocks which are more amenable to out of plane technique and ISB is one of those blocks which can be done easily and safely with this approach.
2- Thinking about phrenic nerve palsy. Do you prefer the down interscalene approach or “the classic” one?
Regardless of whichever approach you may use there will always be a risk of phrenic nerve involvement with ISB as said in the paper unless the local anaesthetic agent is deposited on the brachial plexus at the level of or distal to the clavicle.
3- Going directly to block suprascapular and axillary nerves we can get our morbidity better. Is this a routine practice or maybe this is a theoretical issue?
Anecdotal evidence and logic suggest that there may be decrease in morbidity from avoiding phrenic nerve paresis in those patients who have pre-existing respiratory problems, however if we were to select our patients carefully we can maximise the benefit of the excellent analgesia, technically easy to do and reliable ISB. In those patients who have respiratory impairment it will be prudent to avoid the ISB and opt for the alternate suprascapular and axillary block.