Recently, it has been recognized that the individual celiac ganglia can be visualized and accessed by EUS allowing for direct injection into the individual celiac ganglia to perform celiac ganglion neurolysis (CGN). The celiac ganglia are typically oval or almond shaped ranging in size between 2–20 mm and most readily detected to the left of the celiac artery, anterior to the aorta. Compared to the surrounding retroperitoneal fat, the ganglia are echo poor and often display similar echogenicity to the left adrenal gland. Within the ganglia, often central echo-rich strands and foci are present and the margins of the ganglia are irregular. Color Doppler demonstrates little to no flow within these structures. Ganglia are detected by EUS in between 81 and 89 % of patients [16]. Our approach is to perform CGN rather than CPN if ganglia are visualized although further data are needed on this approach.

All aspects of the procedure including patient candidacy, sedation , antibiotic use, and follow-up are the same as standard CPN/CPB. The technique for CGN and volume of solution injected has not been standardized. Our approach is to target as many ganglia as possible by injecting a total of 10–20 ml of premixed alcohol and bupivacaine (mixture as outlined above) among all the ganglia in amounts relative to their size (Fig. 33.2, see Video 30.1). For example, if three ganglia are visualized (small, medium, and large), we would typically inject 5 ml in the largest ganglion, 3 ml in the medium sized ganglion, and 2 ml in the small ganglion. For larger ganglia, we typically advance the needle tip into the deepest point within the ganglia and then inject while slowly withdrawing the needle, creating an even distribution of injectate throughout the ganglion. For smaller ganglia, we usually target the ganglia’s center. During injection, a clear “ballooning” of the ganglia should be visualized; otherwise, needle placement is considered suboptimal.

The clinical trial data for CGN and CPN for patients with pancreatic cancer are summarized in Table 33.1. Within the literature, there is great variability among the studies in terms of injection technique, type of injectate and volume, definition of pain relief, and follow-up. Most studies are small retrospective studies with short follow-up.

For celiac plexus neurolysis , partial pain relief has been reported between 50 and 78 % within the first 4 weeks [11, 15, 17–19]. A meta-analysis including 119 patients found that EUS-CPN alleviated abdominal pain in 73 % of patients. [20] In a randomized trial, 96 patients with inoperable pancreatic cancer were randomized into conventional pain management or EUS-CPN. At 3 months, patients treated with CPN had greater pain relief with a trend toward lower morphine consumption, although no difference was observed in quality of life [21].

Results of celiac plexus block are less successful than CPN with two meta-analyses reporting 51 and 60 % pain relief [10, 20]. Of those who respond, duration of relief is short-lived at about 4 weeks [13]. A randomized study comparing percutaneous fluoroscopy directed CPB to EUS-CPB in chronic pancreatitis found that significantly more patients reported improvement in pain scores in the EUS group (70 versus 30 %, p = 0.04) [22]. Unfortunately, by 24 weeks following CPB, nearly all patients had returned to their baseline pre-procedure pain score. Another prospective non-randomized study confirmed this lack of durability of pain relief with only 10 % reporting some pain relief at 24 weeks [23].

For celiac ganglion neurolysis, partial pain relief has been reported between 65 and 94 % [24–26]. In the only prospective trial to date comparing CGN to CPN, 68 patients with upper abdominal cancer (over 85 % were pancreatic cancer) were randomly assigned to treatment using either EUS-CGN or EUS-CPN with one midline injection. The positive response rate was significantly higher in the EUS-CGN group (73.5 %) than in the EUS-CPN group (45.5 %). The complete response rate was also significantly higher in the EUS-CGN group (50 %) than in the EUS-CPN group (18.2 %) although the response rate for EUS-CPN was much lower than reported in other studies. There was no difference in adverse events or duration of pain relief between the groups [24]. Follow-up was only 7 days, and much longer term follow-up studies are needed as well as comparison with bilateral EUS-CPN injections.

Most complications related to CPN/CPB and CGN are transient, and serious complications are rare. A large series of 220 patients undergoing EUS-CPN/CPB had an overall complication rate of 1.8 % with complications defined as any side effect requiring management beyond standard post-procedure observation [27]. The most common side effects reported are transient hypotension (up to 35 %), diarrhea (up to 20 %), and transient exacerbation of pain following procedure which are consistent with rates seen with the PQ approach [8]. Hypotension and diarrhea are related to sympathetic blockade and the relative unopposed visceral parasympathetic activity. Hypotension generally responds to intravenous fluid administration. The diarrhea related to this procedure is usually self-limited and resolves in less than 48 h. CPN via a PQ approach has been associated with a 2 % rate of serious complications including neurologic complications (lower extremity weakness, paresthesia, paralysis), pain (pleuritic chest, shoulder), pneumothorax, and hiccupping [8]. A very small number of serious complications (≤ 0.6 %) including fatalities and paralysis mainly with alcohol injection have been reported with the EUS approach in case report and abstract form [28, 29]. Serious infections including retroperitoneal abscess and empyema have occurred as well as severe ischemic damage to abdominal organs.

In the case of Mr. H, celiac neurolysis appears to be an ideal choice for pain relief. His cancer-related pain is clearly not optimized with oral narcotic agents, which are causing side effects of constipation and drowsiness. To date no trials have compared percutaneous to EUS-guided celiac neurolysis; however, our preferred approach in this patient would be EUS-guided celiac ganglion neurolysis although celiac plexus neurolysis is also reasonable. Direct visualization of the celiac ganglia can only be achieved using EUS at the current time and as a result, a non-EUS approach is limited to CPN. Additional well-designed studies are needed to further compare CGN and CPN and to determine the optimal method and timing of celiac neurolysis/block, composition of the injectate, impact on quality of life, and the benefit of this technique in chronic pancreatitis patients.