Persistent, intractable pain. Generally, a block is tried prior to neurolysis with the exception of some cancer pain.
(Celiac plexus) increased gastric motility, confirmation of MALS

Neurolysis can be performed with chemicals (ethanol or phenol), heat (RF ablation), or cold (cryoablation). Chemical neurolysis can be cheaper and more accessible in some setting but has higher risks of complications. RF can be used for neuromodulation or ablation. This often requires general anesthesia. Cryoablation has the advantage of only requiring moderate sedation and ability to target Sunderland grade 2 nerve injury (see below).
Nerve injury as function of cold:
- 10 to -20*C Neuropraxia (reversible) - conduction interrupted, short recovery time
- -20 to -100*C Axonotmesis (reversible at 1.5 mm/d) - loss of axon continuity, Wallerian degeneration
- < -140*C Neurotmesis (nonreversible) - loss of axon continuity as well as some endoneurium and perineurium
Ideally targeting Sunderland Grade 2 nerve injury with cryoneurolysis where the myelin sheath and axon are destroyed but the connective tissues of the nerve remain intact to allow regeneration. Higher grade injury requires -100*C which isn’t possible with current ablation systems. Bigger issue is under treating and causing Sunderland grade 1 injury or neurapraxia, which can worsen symptoms and cause allodynia. Fortunately, this tends to be self-limited.
Main alternatives are analgesics and radiotherapy. Patients should be told that all these interventions are unlikely to completely get rid of the pain. The goal is to reduce it 50% or more and make it more manageable.

Review imaging for planning approach and avoiding surrounding critical structures
Counsel patient to set expectations - Patients should be told up front that nothing will likely get rid of the pain completely and if anyone tells you that, they’re lying. The goal is to reduce the pain 50% or more and make it manageable.

Block (general)

US or CT guidance with small gauge needle, e.g., 22 G. Nice to have patients conscious for immediate feedback such as testing with lidocaine. Reproducing the pain with needle position is also a good sign that this is the right target.
Prologo uses 1 mL/6 mg betamethasone and 5 mL 0.25% bupivacaine for blocks. Lots of various combinations out there but generally an anesthetic and steroid.

Celiac Block/Neurolysis

Lots of variation in approaches. Can can be retrograde (through back) or antegrade, bilateral or unilateral, antecrural or retrocrural or a combination.
Target: Celiac ganglia in para-aortic region between celiac axis and SMA 1-2 cm anterior to aorta between diaphragmatic crura and pancreas. Some people think of them in four quadrants around the celiac axis.
Advance 25G needle to target for localization/numbing. Some go straight with a 20-22G Chiba.
Advance 20-22G Chiba(s) to target. Can be done with CT guidance (most common) or ultrasound or fluoroscopy.
Aspirate to exclude being intravascular.
(Optional) Hydrodissection as needed to protect critical surrounding structures.
Dilute contrast injection (2-3 mL) looking for spread through the target region. Can require 1-4 needles for good spread. Can also start retro or antecrural and pull back to the other to get both.
Administer block or lysis
- Block - bupivacaine/Kenalog (20-24 mL total split between right and left)
- Chemolysis - ethanol (more common) or phenol
  - Dehydrated ethanol - 40-60 mL, less viscous, transient pain at injection, faster onset
  - Phenol - 20-25 mL, more viscous, no pain at injection, slower onset
- Cryolysis - position 17F cryoablation probe and perform single freeze-thaw cycle
Final imaging to confirm no complications.

Splanchnic

Plexus running down lateral aspects of lower thoracic or upper lumbar vertebra. Common target is retrocrural space lateral to T12 bilaterally.

Intercostal nerve

Common neuralgia associated with thoracic and breast surgeries.
Thermal ablation 80*C for 3 minutes OR cryoneurolysis with IceSphere for 12 minutes.

Pudendal nerve

Ganglion Impar

Other common targets

Variable depending on nerve/site treated.

Celiac plexus

96% Transient back pain (up to 72 hrs)
10-52% Orthostatic hypotension
44% Diarrhea, usually transient but can be chronic (can try opium tincture or IM octreotide)

Monitoring in post-op for complications such as bleeding or orthostatic hypotension
Follow up clinic visit for symptom relief and see where repeat procedure is indicated

Nerve Blocks and Neurolysis