Describe the anatomy of the coeliac plexus. What are the indications for its therapeutic blockade?

This question comes as a surprise for many candidates, but the anatomy of the area is important and coeliac plexus block is very effective for malignant pain.

Introduction

The coeliac plexus is most commonly the target for anaesthetists who are treating malignant visceral pain. The anatomy may be described as follows:

• The coeliac plexus is the largest sympathetic plexus and lies anterior to the abdominal aorta where as a dense network of nerve fibres it surrounds the root of the coeliac artery at the level of L1 .

• There are two ganglia, right and left, which are closely related to the crura of the diaphragm.

• The plexus receives the greater splanchnic nerve (fibres from T5 to T9 or 10) and the lesser splanchnic nerve (fibres from T9/10 or T10/11).

• The plexus also receives some filaments from both the vagus and the phrenic nerves bilaterally.

• Superiorly lie the crura of the diaphragm; posteriorly is the abdominal aorta; laterally are the adrenal glands in the superior poles of left and right kidneys; the important anterior relation is the pancreas.

• Therapeutic block. The plexus can be blocked in conjunction with intercostal nerves in order to provide analgesia for intra-abdominal surgery. This technique does not have many enthusiasts. More commonly it is used for the relief of malignant pain, typically that due to carcinoma of the pancreas. Neurolytic blocks give good analgesia in up to 90% of patients, although the effect may only last for a number of months.

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