Abdominal pain caused by chronic pancreatitis can be severe
and incapacitating, difficult to control, and not surprisingly
results in significant morbidity impacting quality of
life and employment. Oral analgesia remains the mainstay of
therapy, but when the pain is more severe, invasive treatments
are often considered. Such invasive therapy is guided by the
pancreatic ductal and parenchymal anatomy as assessed by
cross-sectional abdominal imaging. If ductal dilatation and/or
obstruction are present, then endoscopic or surgical treatment
is preferred.1 The more difficult patients are those who have not
responded to such therapy or who have unfavorable anatomy
for such interventions. In this setting, direct attack on the
nociceptive pathways might be considered; currently, celiac
plexus block (CPB) is the principal option.
CPB is performed by injecting an anesthetic and steroid
agent into the CP, whereas celiac plexus neurolysis (CPN) involves
using an anesthetic with an ablative agent, most often
absolute alcohol. Until recently such interventions have been
administered percutaneously via a posterior approach or intraoperatively,
but with the advent of endoscopic ultrasound
(EUS), CP injections can now be given with more precision
because of the ability of EUS to identify the celiac ganglia. The
side effects of CPB are generally mild and include transient
diarrhea, hypotension, and pain. CPN also has a favorable side
effects profile, but severe complications have been reported
including lower extremity paralysis.2
Despite the theoretical appeal and infrequency of major side
effects, outcomes of CPN in relieving pancreatic cancer pain
have been mixed, with approximately 75% of patients reporting
a reduction in pain.3 In some patients pain relief can be immediate
and long-lasting, whereas in others, pain relief is only
modest, evanescent, or unaffected. Opioid consumption might
be reduced but is infrequently completely discontinued.2–5 Surprisingly,
quality of life is inconsistently affected, and no effect
on mortality has been shown.4,5 Recently the superiority of this
technique was confirmed in a randomized blinded fashion
compared with no treatment at the time of pancreatic cancer
diagnosis by EUS.6 It should be noted that in this trial all
patients randomized to CPN received CPN whether they had
pain or not at baseline and thus reflects a different population
than pancreatic cancer patients who are referred for CPN because
of severe refractory pain.
Another more aggressive treatment also targeting an interruption
of the efferent nervous system used for the treatment of
pancreatic cancer and subsequently to chronic pancreatitis is
thoracoscopic splanchnicectomy. Like CPN, the results have
been mixed,7–10 with short-term pain relief in about half of the
patients; the response attenuates over time, and complete pain
relief is rare. Some have used antecedent differential epidural
analgesia to determine who might most benefit.11 Such an
attenuating effect over time has also been seen with surgical
duct decompression.12
It is on this background of “efficacy” for CPN in pancreatic
cancer pain therapy that CPB has been extrapolated to and
promulgated for chronic pancreatitis. Technically, as noted
above, EUS offers an advantage because the anterior approach
can be more easily performed with EUS guidance rather than
the posterior approach performed percutaneously. It must be
remembered, however, that although the pain in chronic pancreatitis
and pancreatic cancer might originate from the same
organ, the underlying pathophysiological mechanism(s) of pain
and patient substrate are quite different. For example, the
patient with chronic pancreatitis often has pain for a much
more prolonged period of time, and this is often on a milieu of
alcohol or narcotic addiction or other substance abuse. Patients
with chronic pain have been shown to have structural reorganization
of the central nervous system.13 Specifically for patients
with chronic pancreatitis, visceral hypersensitivity with
evidence for sensitization and cerebral reorganization as well as
alterations in cortical thickness in areas involving visceral pain
processing have also been shown.14 A central origin for pain is
further supported by the fact that differential nerve blockade, a
technique whereby anesthesia is applied to the spinal canal,
completely disrupting sensation, might be ineffective in relieving
pain in patients with chronic pancreatitis.15
What are the quantity and quality of published data on the
efficacy of CPB or CPN for the treatment of pain in chronic
pancreatitis? The majority of the studies have evaluated CPB,
and the overall response rate is 50%16–18; there are very few
data on use of CPN in this setting.19 Although prospective and
using similar techniques for blockade, the trials used different
outcome measures for pain relief, long-term follow up was
inadequate, blinding was not uniform, quality of life was not
assessed, and most importantly, CPB was not compared with a
placebo or a sham group. In any trial in which subjective
measures are used for outcome, classically those involving pain,
blinding, and use of a placebo or sham arm are essential to
prove efficacy. Furthermore, although these studies show pain
relief in approximately half the patients, a reduction in pain is
rarely associated with a significant drop in narcotic use, and it
is not long-lasting. Because this is a lifelong disease, even using
a treatment that provides only a very short-lived response is not
inherently logical.
Because of the limited efficacy, especially because pain relief
is short-lived at best, and the absence of any well-done controlled
studies, why would we accept such a technique as effective?
Extrapolation of the same technique in pancreatic cancer
and the “good” outcomes is one potential reason. A more
realistic explanation is the fact that the armamentarium for
treatment of pain in these patients is limited, and thus both
patients and doctors believe they “have to do something” even
if it does not work.
Abdominal pain caused by chronic pancreatitis can be severe
and incapacitating, difficult to control, and not surprisingly
results in significant morbidity impacting quality of
life and employment. Oral analgesia remains the mainstay of
therapy, but when the pain is more severe, invasive treatments
are often considered. Such invasive therapy is guided by the
pancreatic ductal and parenchymal anatomy as assessed by
cross-sectional abdominal imaging. If ductal dilatation and/or
obstruction are present, then endoscopic or surgical treatment
is preferred.1 The more difficult patients are those who have not
responded to such therapy or who have unfavorable anatomy
for such interventions. In this setting, direct attack on the
nociceptive pathways might be considered; currently, celiac
plexus block (CPB) is the principal option.
CPB is performed by injecting an anesthetic and steroid
agent into the CP, whereas celiac plexus neurolysis (CPN) involves
using an anesthetic with an ablative agent, most often
absolute alcohol. Until recently such interventions have been
administered percutaneously via a posterior approach or intraoperatively,
but with the advent of endoscopic ultrasound
(EUS), CP injections can now be given with more precision
because of the ability of EUS to identify the celiac ganglia. The
side effects of CPB are generally mild and include transient
diarrhea, hypotension, and pain. CPN also has a favorable side
effects profile, but severe complications have been reported
including lower extremity paralysis.2
Despite the theoretical appeal and infrequency of major side
effects, outcomes of CPN in relieving pancreatic cancer pain
have been mixed, with approximately 75% of patients reporting
a reduction in pain.3 In some patients pain relief can be immediate
and long-lasting, whereas in others, pain relief is only
modest, evanescent, or unaffected. Opioid consumption might
be reduced but is infrequently completely discontinued.2–5 Surprisingly,
quality of life is inconsistently affected, and no effect
on mortality has been shown.4,5 Recently the superiority of this
technique was confirmed in a randomized blinded fashion
compared with no treatment at the time of pancreatic cancer
diagnosis by EUS.6 It should be noted that in this trial all
patients randomized to CPN received CPN whether they had
pain or not at baseline and thus reflects a different population
than pancreatic cancer patients who are referred for CPN because
of severe refractory pain.
Another more aggressive treatment also targeting an interruption
of the efferent nervous system used for the treatment of
pancreatic cancer and subsequently to chronic pancreatitis is
thoracoscopic splanchnicectomy. Like CPN, the results have
been mixed,7–10 with short-term pain relief in about half of the
patients; the response attenuates over time, and complete pain
relief is rare. Some have used antecedent differential epidural
analgesia to determine who might most benefit.11 Such an
attenuating effect over time has also been seen with surgical
duct decompression.12
It is on this background of “efficacy” for CPN in pancreatic
cancer pain therapy that CPB has been extrapolated to and
promulgated for chronic pancreatitis. Technically, as noted
above, EUS offers an advantage because the anterior approach
can be more easily performed with EUS guidance rather than
the posterior approach performed percutaneously. It must be
remembered, however, that although the pain in chronic pancreatitis
and pancreatic cancer might originate from the same
organ, the underlying pathophysiological mechanism(s) of pain
and patient substrate are quite different. For example, the
patient with chronic pancreatitis often has pain for a much
more prolonged period of time, and this is often on a milieu of
alcohol or narcotic addiction or other substance abuse. Patients
with chronic pain have been shown to have structural reorganization
of the central nervous system.13 Specifically for patients
with chronic pancreatitis, visceral hypersensitivity with
evidence for sensitization and cerebral reorganization as well as
alterations in cortical thickness in areas involving visceral pain
processing have also been shown.14 A central origin for pain is
further supported by the fact that differential nerve blockade, a
technique whereby anesthesia is applied to the spinal canal,
completely disrupting sensation, might be ineffective in relieving
pain in patients with chronic pancreatitis.15
What are the quantity and quality of published data on the
efficacy of CPB or CPN for the treatment of pain in chronic
pancreatitis? The majority of the studies have evaluated CPB,
and the overall response rate is 50%16–18; there are very few
data on use of CPN in this setting.19 Although prospective and
using similar techniques for blockade, the trials used different
outcome measures for pain relief, long-term follow up was
inadequate, blinding was not uniform, quality of life was not
assessed, and most importantly, CPB was not compared with a
placebo or a sham group. In any trial in which subjective
measures are used for outcome, classically those involving pain,
blinding, and use of a placebo or sham arm are essential to
prove efficacy. Furthermore, although these studies show pain
relief in approximately half the patients, a reduction in pain is
rarely associated with a significant drop in narcotic use, and it
is not long-lasting. Because this is a lifelong disease, even using
a treatment that provides only a very short-lived response is not
inherently logical.
Because of the limited efficacy, especially because pain relief
is short-lived at best, and the absence of any well-done controlled
studies, why would we accept such a technique as effective?
Extrapolation of the same technique in pancreatic cancer
and the “good” outcomes is one potential reason. A more
realistic explanation is the fact that the armamentarium for
treatment of pain in these patients is limited, and thus both
patients and doctors believe they “have to do something” even
if it does not work.
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