Coeliac plexus block

Coeliac plexus block under image guidance is an easy and safe percutaneous procedure with good outcomes for pain palliation in patients who have chronic abdominal pain related to the coeliac plexus. 

This usually includes patients with advanced cancers, especially from upper abdominal viscera, such as the pancreas, stomach, duodenum, proximal small bowel, liver and the biliary tract, or due to enlarged lymph nodes.

Indications

• persistent, intractable abdominal or localised back pain due to malignant disease in the upper abdomen
• failure of standard pain control therapy

Contraindications

These are relative and include:

• severe uncorrectable coagulopathy or thrombocytopenia
• abdominal aortic aneurysm
• eccentric origin of the coeliac artery
• inability to visualise local anatomy due to large overlying soft tissue mass

Procedure

Equipment

Although fluoroscopy was the earliest method of image guidance used, CT is the commonest modality that has been subsequently described to date. Some operators have described the use of ultrasound which allows for easy visualisation of the coeliac vessels but is operator and patient-dependent.

Technique

Coeliac ganglia are located anterior to the crura of the diaphragm, over the anterolateral wall of the aorta bilaterally, and just caudal to the level of the origin of the coeliac artery. Both anterior and posterior approaches may be used to access these, depending on the operator’s preferences and the safest route of access.

The anterior approach carries a reduced risk of neurologic complications since the needle tip is anterior to the spinal arteries and spinal canal. This also allows for a single puncture, reduced procedure time and use of a smaller volume of neurolytic agent. It also avoids the risk of puncturing the aorta and permits the patients to remain supine during the whole procedure.

20 to 50 mL of ethanol, with concentrations of 50–100%, is the most commonly used neurolytic agent in clinical practice. Phenol is also used as a neurolytic agent. Bupivacaine or lidocaine, as local anaesthetics, have been used for coeliac plexus block.

Postprocedural care

Patients are usually admitted for close haemodynamic and neurological monitoring overnight. They should be kept well-hydrated using IV fluids as necessary as there is a risk of periprocedural hypotension.

Complications

Pain

Local posterior abdominal and back pain during or immediately after a coeliac plexus block has been reported commonly because of the ablative effect of the neurolytic agent. 

Diarrhoea

Often self-limiting, diarrhoea occurs due to sympathetic blockade and unopposed parasympathetic efferent influence after the block. It usually resolves over approximately 48 hours.

Orthostatic hypotension

This may occur due to loss of sympathetic tone and dilated abdominal vasculature. It is usually transient (few hours) and can be managed conservatively with IV fluids as required.

Neurological

Paraplegia, leg weakness, sensory deficits, and paraesthesias have rarely been reported. This is attributed to either direct injury of the spinal cord during the procedure or injection into the anterior spinal artery, which supplies the lower two thirds of the spinal cord.

Other

Puncture complications to the upper abdominal viscera (e.g. liver, stomach, pancreas and bowel) are rare. 

Other rarely reported complications include impotence, gastroparesis, superior mesenteric vein thrombosis, chylothorax, pneumothorax, chemical pericarditis, aortic pseudoaneurysm, aortic dissection, haemorrhage and retroperitoneal fibrosis.

Outcomes

All patients should be interviewed before the procedure to obtain a baseline pain score to compare with post-procedural pain. A visual analogue scale can be used to quantify a patient's subjective pain while the doses of pain medication taken can be used as objective markers of procedural outcome.

History and etymology

Splanchnic nerve block for pain from the upper abdominal viscera was first described by Maxi Kappis in 1914 using bony landmarks from a posterior approach. He demonstrated that this could be used as a form of surgical anaesthesia.

As image guidance started becoming widespread in the 1950s, Jones (1957) described the use of ethanol-induced coeliac plexus neurolysis for long term pain relief. This method is now well-established.