Caudal

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.

Anatomy

Patient Position