Ultrasound-guided quadratus lumborum block compared to caudal ropivacaine/morphine in children undergoing surgery for vesicoureteric reflex
Background
Ultrasound guided quadratus lumborum (QL) block is a relatively new regional technique in paediatric abdominal surgery. It is based on the assumption that local anaesthetic spreads from the QL muscle into the paravertebral space providing somatic and possibly visceral pain relief (ie. from bladder spasms). Previous studies have shown that TAP blocks have a longer duration of action compared to caudal analgesia and that QL blocks are superior when compared to TAPs. The authors hypothesized that a QL block would provide equivalent analgesia to a caudal block, however, with a longer duration of action and better overall pain relief in the initial 24 hour period.
Methods
This was a single centre RCT from Japan with adequate power. There were 44 children included between 1 and 17 years of age undergoing bilateral ureteric reimplantation. Both QL and caudal blocks were ultrasound guided, standardised and performed by a single operator. Induction and maintenance of anaesthesia was standardised. All patients received regular acetaminophen and a fentanyl infusion for 48 hours as well as parent/nurse controlled analgesia (PNCA). The primary outcome was the number of PNCA boluses within the first 24 hours. Secondary outcomes included the number of PNCA boluses at 30 min, 4 hours and 48 hours, maximum remifentanil dose intra-operatively, CHEOPS scores, episodes of vomiting and other complications.
Results
Patients randomised to QL block had a significantly lower PNCA dose in the first 24 hours but no difference at 30min, 4 or 48 hours. This is in-line with the author’s hypothesis. These patients also had a higher maximum intraoperative remifentanil dose suggesting potentially lower intra-operative efficacy. There were no other differences in outcomes
Limitations
This study was conducted in a single centre with a single operator performing the blocks, making application to other anaesthetists and centres difficult. There was also a large range of ages, including older children where caudals may be more difficult and less effective.
Take Home Message
QL blocks are a promising alternative to caudal analgesia for open urological surgery. They likely provide equivalent post-operative analgesia to caudal blockade with a longer duration of action, however, are potentially less effective intraoperatively and probably more time consuming. As a single centre/operator study, these results are difficult to extrapolate.
Reviewed by: Dr Matt Mathieson
