Is there a role for celiac plexus block for chronic pancreatitis?

Endoscopic ultrasound–celiac plexus block (EUSCPB) and endoscopic ultrasound–celiac plexus neurolysis (EUS-CPN) have been reported to provide pain relief and reduce narcotics use in patients with chronic pancreatitis [1]. The techniques of EUS-CPB and EUS-CPN are identical; the differences are in the substances injected and in the indications. Neurolysis, in which bupivacaine and ethanol are injected, has been used in patients who have pancreatic cancer or chronic pancreatitis. On the other hand, block, in which bupivacaine with or without triamcinolone is injected, has been usedmainly in patients who have chronic pancreatitis [2]. The injection of ethanol, bupivacaine, and triamcinolone into the celiac plexus disrupts signal transmission to the spinal cord and central nervous system, theoretically interfering with the perception of pain. The effects of ethanol are much less reversible than the effects of bupivacaine and triamcinolone, and albeit rare, more severe adverse effects have been reported with EUS-CPN than with EUS-CPB [3–5]. Moreover, meta-analysis of EUS-CPN showed results in patients with pain due to chronic pancreatitis (pain relief in 59% of 376 patients in 9 studies) that were inferior to results in patients with pancreatic cancer (pain relief in 80% of 283 patients in 8 studies) [6]. For these reasons, EUS-CPN is the technique of choice for patients with pancreatic cancer, whereas EUS-CPB is preferred for patients affected with a benign condition, such as chronic pancreatitis. Because of the anatomical location of the celiac plexus around the origin of the celiac trunk and superior mesenteric artery, the EUS-guided technique provides near-field and real-time visualization, resulting in a safer approach than is possible with percutaneous techniques [7]. A randomized, controlled trial, in which EUS-guided and fluoroscopy-guided percutaneous CPBwith bupivacaine and triamcinolone were compared in patients who had chronic pancreatitis, demonstrated improvement in pain scores (visual analogue scale) in 70% of patients in the EUS group versus 30% of those in the percutaneous group (P=0.044) [8]. However, the efficacy of EUS-CPB has been questioned because of inconsistent results in terms of the degree and duration of pain reduction in published studies [8–14] (●" Table1). A systematic review of the efficacy of steroid-based EUS-CPB in patients with refractory pain due to chronic pancreatitis (6 studies including 221 patients) showed satisfactory reduction of abdominal pain in only 51% of patients [15]. Moreover, in a study in which 40 patients were randomized to receive either bupivacaine alone or bupivacaine and triamcinolone, no significant difference in pain control was found between the two groups (14% vs. 16% for controls) [14]. Sey et al. have offered an original perspective on the topic of EUS-CPB, addressing the problem of the short duration of its effects [16]. From a huge EUS-CPB database of 1108 patients treated at the Indiana University Medical Center, Indianapolis, Indiana, USA, they extrapolated data for 248 patients with chronic pancreatitis who underwent two or more procedures and investigated the incremental effects of repeated EUS-CPB procedures. Either a standard 22-gauge needle or a dedicated 20-gauge needle with sideholes at the end was used for EUS-CPB. When visible, the celiac ganglia were targeted; otherwise, 20mL of 0.75% bupivacaine followed by 40 to 80mg of triamcinolone, according to the endosonographer’s preference, was injected at the level of the celiac trunk. The majority of the patients underwent 2 to 4 procedures, but some had 5 to 6 and a few of them even had up to 10 EUS-CPB procedures. After the first session, 76% of the patients reported pain relief, a value in line with the upper limit of the range of effectiveness reported in the literature. The median duration of pain relief was 10