Endoscopic ultrasound–celiac plexus block (EUS-CPB) 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 used mainly 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]
[4]
[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
CPB with 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]
[9]
[10]
[11]
[12]
[13]
[14] ([Table 1]). 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].
Table 1
Endoscopic ultrasound and celiac plexus block in chronic pancreatitis.
|
Article
|
Study
|
Patients
|
Techniques
|
Technical success
|
Clinical success
(pain relief)
|
Complications
|
|
Gress et al., 1999
|
RCT
|
n = 10
n = 8
|
EUS-CPB
CT-CPB
|
100 %
|
50 %
25 %
|
None
|
|
Gress et al., 2001
|
PS
|
n = 90
|
EUS-CPB
|
100 %
|
55 %
|
3 diarrhea
|
|
Levy et al., 2008
|
RS
|
n = 18
|
EUS-CGN (n = 5)
EUS-CGB (n = 13)
|
–
|
80 %
38 %
|
12 hypotension
6 diarrhea
|
|
O'Toole et al., 2009
|
RS
|
n = 128
|
EUS-CPB
|
–
|
–
|
2 post-procedural pain
1 retroperitoneal abscess
|
|
1 hypotension
|
|
Santosh et al., 2009
|
RCT
|
n = 27
n = 29
|
EUS-CPB
Percutaneous CPB
|
100 %
–
|
70 %
30 %
|
2 diarrhea
|
|
Leblanc et al., 2009
|
RCT
|
n = 23
n = 27
|
EUS-CPB (central)
EUS-CPB (bilateral)
|
100 %
|
65 %
59 %
|
None
|
|
Stevens et al., 2012
|
RCT
|
n = 40
|
Triamcinolone + bupivacaine (n = 21)
Bupivacaine alone (n = 9)
|
100 %
|
68 % – 86 %
|
1 severe hypertension
4 pain exacerbation
1 gastric hematoma
|
RCT, randomized controlled trial; EUS, endoscopic ultrasound; CPB, celiac plexus block;
CT, computed tomography; PS, prospective study; RS, retrospective study; CGN, celiac
ganglia neurolysis; CGB, celiac ganglia block.
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,
20 mL of 0.75 % bupivacaine followed by 40 to 80 mg 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 weeks. Subsequent EUS-CPB procedures produced fairly longer intervals of pain
relief (12 – 20 weeks). Failure to obtain pain relief after the first EUS-CPB was
associated with failure after subsequent EUS-CPB procedures. On the other hand, older
age (P = 0.026) and pain relief after the first block (P = 0.0024) were associated with pain relief after subsequent EUS-CPB procedures. Finally,
the number of EUS criteria for chronic pancreatitis was not associated with pain relief.
Given the nearly complete absence of complications (only 3 minor transient events
occurred), the study of Sey et al. is a unique and interesting demonstration of the
feasibility and efficacy of repeated EUS-CPB procedures to control pain in patients
with chronic pancreatitis. Given the benign but chronic nature of chronic pancreatitis,
these patients are natural candidates to undergo a treatment that is reasonably effective,
safe, and repeatable.
The good results of the study from the Indiana University Medical Center agree with
those of an ongoing randomized, multicenter trial comparing EUS-CPB (bupivacaine + triamcinolone)
with a sham procedure, in which patients are blinded to the procedure, and should
revive interest in EUS-CPB. In preliminary results, the rate of pain reduction was
significantly higher in the treated arm than in the sham arm; morphine use was also
reduced in the treatment group, although the difference between the treatment group
and the sham group was not significant. Crossover to the active treatment was requested
by 100 % of the patients in the sham group after a median of 46 days [17].
In summary, according to this new evidence, EUS-CPB appears to be a safe, moderately
effective, and repeatable treatment for patients with pain caused by chronic pancreatitis.
Of course, recourse to EUS-CPB should be weighed against the alternative options that
are available. These include lifestyle changes (e. g., cessation of alcohol and tobacco
use), supplementation of pancreatic enzymes, and psychosocial support to reduce opiate
dependence. For patients who have severe disease with main pancreatic duct dilatation,
endoscopic or surgical duct decompression and total pancreatectomy with islet auto-transplantation
are also options. Gastroenterologists must use their clinical judgment in order to
select the patients who may benefit from EUS-CPB (e. g., those who experienced relief
after a previous EUS-CPB procedure and those who are elderly). On the other hand,
precious time should not be wasted on EUS-CPB when it is ineffective; in these cases,
other treatments should be readily adopted before the disease becomes too advanced
(with the development of excessive organ fibrosis and nociceptive pathway remodeling)
to respond even to surgical treatment [18].
