Unilateral sacral erector spinae plane block for lower limb surgery in children

The erector spinae plane block is a versatile regional anaesthesia technique used for a variety of truncal surgeries. A novel variation is the sacral erector spinae plane block which is gaining popularity for perineal and anorectal procedures. Local anaesthetic injected at this level blocks the sacral dermatomes and has the potential for more proximal spread to involve lumbar nerve fibres via spread to the lumbar plexus or the epidural space. The advantage of a sacral erector spinae plane block over a neuraxial block is that it is less invasive and may have a better safety profile: there is a reduced risk of epidural haematoma, epidural abscess, haemodynamic instability and motor weakness of the lower extremities. Until now, this approach has been used for midline surgical procedures when the local anaesthetic was injected bilaterally. Its application for lower limb procedures with a single unilateral injection has not been described. We report the use of a unilateral sacral erector spinae plane block at the level of the S2 median crest in two children undergoing lower limb procedures of the hip and thigh. The block was found to provide effective peri-operative analgesia with minimal need for any opioid analgesics and without any significant adverse effects.