Very safe, can be used to provide peri- and postoperative analgesia, can be sole anesthetic or can be combined with general anesthesia.
a. Anesthesia and analgesia below the umbilicus – the very young a caudal block may be adequate to carry out urgent procedures such as reduction of incarcerated hernias -superficial operations such as skin grafting, perineal procedures, and lower limb surgery. GA may be required in addition Pain relief will extend into the post operative period. The duration of the block can been prolonged by the addition of an opiate (pethidine 0.5 mg/kg) to the local anaesthetic. b. Obstetric analgesia for the 2nd stage or instrumental deliveries. Care should be taken as the fetal head lies close to the site of injection and there is real risk of injecting local anaesthetic into the fetus c. chronic pain problems such as leg pain after prolapsed intervertebral disc, or post shingles pain below umbilicus.
- Infection at site
- Pilonidal cyst
- Congenital anomaly of spine or meninges
caudal epidural space: lowest portion of the epidural system and is entered through the sacral hiatus. The sacrum is a triangular bone that consists of the five fused sacral vertebrae (S1- S5). It articulates with the fifth lumber vertebra and the coccyx. The sacral hiatus is a defect in the lower part of the posterior wall of the sacrum formed by the failure of the laminae of S5 and/or S4 to meet and fuse in the midline. There is a considerable variation in the anatomy of the tissues near the sacral hiatus, in particular, the bony sacrum. The sacral canal is a continuation of the lumbar spinal canal which terminates at the sacral hiatus.
The volume of the sacral canal can vary greatly between adults.
- 0.25 percent bupivacaine (Marcaine), preservative free at 2 mg/kg
- adults usually get 20 to 30cc for analgesia for lower extremity
- can be done in prone or semiprone or lateral position
- find landmarks: The sacral hiatus can be located by first palpating the coccyx, and then sliding the palpating finger in a cephalad direction (towards the head) until a depression in the skin is felt.
- Once the sacral hiatus is identified the area above is carefully cleaned with antiseptic solution, and a 22 gauge short bevelled cannula or needle is directed at about 45° to skin and inserted till a “click” is felt as the sacro-coccygeal ligament is pierced. The needle is then carefully directed in a cephalad direction at an angle approaching the long axis of the spinal canal.
- The needle should be aspirated looking for either CSF or blood. A negative aspiration test does not exclude intravascular or intrathecal placement. Care should always be taken to look for signs of acute toxicity during the injection. The injection should never be more than 10 ml/30 seconds
- A small amount of local anaesthetic should be injected as a test dose (2-4mls). It should not produce either a lump in the subcutaneous tissues, or a feeling of resistance to the injection, nor any systemic effects such as arrhythmias, peri-oral tingling, numbness or hypotension. If the test dose does not produce any side effects then the rest of the drug is injected, the needle removed and the patient positioned for surgery.
- Intravascular or intraosseous injection. This may lead to grand mal seizures and/or cardio-respiratory arrest.
- Dural puncture. Extreme care must be taken to avoid this as a total spinal block will occur if the dose for a caudal block is injected into the subarachnoid space. If this occurs then the patient will become rapidly apnoeic and profoundly hypotensive. Management includes control of the airway and breathing, and treatment of the blood pressure with intravenous fluids and vasopressors such as ephedrine.
- Perforation of the rectum. While simple needle puncture is not important, contamination of the needle is extremely dangerous if it is then inserted into the epidural space.
- Urinary retention.
- Absent or patchy block