Indication
Infraumbilical and lower limb surgery
e.g. hypospadias, bilateral inguinal herniotomy, bilateral orchidopexy, bilateral lower limb surgery, anorectoplasty
Useful for bilateral surgery in small children where the weight-based volume of local anaesthetics is limited. It provides a dense block and can significantly reduce the need for opioids and the doses of general anaesthesia. However, compared to a peripheral block, a caudal block carries more risk, and the duration of the analgesia will be shorter.
Considerations
Is a central block –> so consider other (more peripheral) blocks
Level of block = volume dependent;
NOTE: in children > 2 years the cephalad spread of LA is unpredictable + they may not appreciate the sensation of numbness/pins and needles –> consider alternative block
Possible hypotensive response due to vasodilatation of the lower limbs
Urinary retention
Motor block lower limbs
Contraindications
See general LRA CI
Spinal dysraphism (see cutaneous stigmata and US image)
Severe coagulopathy
Increased intracranial pressure
Caution with
Spinal stenosis patients
Hypovolemic patients
Complications
Intravascular injection -> risk of Local Anaesthetic Systemic Toxicity (LAST)
Intrathecal injection -> total spinal anaesthesia
Failure or inadequate block
WHY ULTRASOUND
The conventional approach for performing a caudal block has historically involved the use of a landmark technique, which remains the predominant method to date. Nevertheless, ultrasound presents an opportunity to enhance the safety and effectiveness of this procedure.
- It helps in identifying spinal dysraphism (contraindication for the block; see image library)
- It aids in identifying the correct location for needle insertion and will subsequently confirm the needle tip position when injecting
- It visualises the caudal sac and thus will prevent intrathecal injection.
- Utilising saline for the initial injection reduces the likelihood of intravascular administration of local anaesthetic, thereby minimising the risk of local anaesthetic toxicity.
- It allows you to follow the spread of the local anaesthetic and confirm the level of the block.