What is the recommended procedure for a sympathetic block?

Sympathetic Block Procedure Recommendations

Sympathetic blocks should be performed with local anesthetics under image guidance (fluoroscopy or ultrasound), with specific techniques tailored to the targeted sympathetic ganglion location. 1

Types of Sympathetic Blocks and Their Indications

• Sympathetic blocks are performed at pre- and paravertebral sympathetic ganglia including stellate ganglion, celiac plexus, lumbar sympathetic ganglia, and superior hypogastric plexus 2
• Indications include complex regional pain syndrome (CRPS), phantom limb pain, central pain, visceral pain from pancreatic cancer, and other cancer-related pain 1, 2
• Neurolytic sympathetic blocks should be limited to patients with short life expectancy (typically producing a block lasting 3-6 months) 1

General Procedural Guidelines

• Patient preparation requires standard aseptic technique similar to neuraxial procedures 1
• Resuscitative equipment, oxygen, and emergency drugs should be immediately available 3
• Blocks should be performed with image guidance - either fluoroscopy (traditional) or ultrasound (increasingly used) 1, 4
• The lowest effective dose of local anesthetic should be used to avoid systemic toxicity 3
• Frequent aspirations should be performed before and during injections to avoid intravascular administration 3

Specific Block Techniques

Stellate Ganglion Block

• Most commonly performed at C6 (54%) or C7 (41%) vertebral level 5
• Typically uses 5-10 mL of local anesthetic (most commonly 0.25% bupivacaine) 5
• Can be performed under fluoroscopic or ultrasound guidance, with ultrasound becoming increasingly preferred, especially in academic centers 5

Lumbar Sympathetic Block

• Most commonly performed at L3 (53%) or L2 (39%) vertebral level 5
• Typically uses 10-20 mL of local anesthetic (most commonly 0.25% bupivacaine) 5
• Fluoroscopic guidance is traditional, but ultrasound guidance is emerging as an alternative approach 4, 5

Celiac Plexus Block

• Indicated for pain due to pancreatic cancer and upper abdominal visceral pain 1
• Can be performed via anterior or posterior approach under fluoroscopic guidance 1
• Echo-endoscopic guidance is an emerging technique, placed in the stomach just below the cardia 1
• Appears safe and effective for pain reduction in pancreatic cancer with significant advantage over standard analgesic therapy for up to 6 months 1

Superior Hypogastric Plexus Block

• Used for pelvic pain of visceral origin 1
• Neurolytic blocks can be considered for cancer pain in this region 1

Medication Selection and Dosing

• Local anesthetic: 0.25% bupivacaine is most commonly used 5
• Volume: 5-10 mL for stellate ganglion block; 10-20 mL for lumbar sympathetic block 5
• Approximately 50% of physicians add other medications, most commonly steroids 5
• For neurolytic blocks in cancer patients with short life expectancy, alcohol or phenol may be used 1
• Botulinum toxin type B has been reported as an adjunct for prolonged sympathetic blockade in CRPS 6

Safety Considerations and Monitoring

• Blood pressure and electrocardiogram monitoring is recommended, especially in patients with high cardiovascular risk 1
• Observe for subjective symptoms and objective findings of sympathomimetic effects if using agents like epinephrine 1
• Ultrasound guidance should be used when possible to reduce the risk of local anesthetic systemic toxicity 1
• Calculate safe dose of local anesthetic based on patient weight to prevent toxicity 1

Treatment Protocol Considerations

• Most physicians perform 1-3 consecutive blocks 5
• Blocks are typically repeated if a patient receives at least 50% pain relief from the previous block lasting 1-7 days 5
• For CRPS, evidence for long-term efficacy is limited despite widespread use 7

Potential Complications and Precautions

• Risk of intravascular injection - requires careful aspiration before injection 3
• Risk of pneumothorax with stellate ganglion block - proper technique and imaging guidance essential 1
• Neurolytic blocks on peripheral nerves can lead to neuritis; use caution in patients with good prognosis 1
• For blocks near the head and neck area, consider additional precautions against airborne transmission (particularly relevant during infectious disease concerns) 1