Celiac plexus/ganglion block is used for palliation of severe upper abdominal pain
caused by chronic pancreatitis or tumors of the pancreas.
Celiac ganglia are located at T12–L1 level in relation to the celiac axis and superior
mesenteric artery (SMA). It is predominantly composed of sympathetic and parasympathetic
efferent fibers and visceral sensory afferent fibers. The preganglionic sympathetic
efferent supply stems from greater splanchnic (T5–T9), lesser splanchnic (T10–T11),
and least splanchnic (T12) nerves. This supply is derived from posterior cord of the
vagus nerve ([Fig. 1]). Visceral afferent nociceptive fibers are received from the liver, pancreas, gallbladder,
spleen, adrenals, kidneys, and bowel (distal esophagus till transverse colon).[1] Topographically, the innervation of the uncinate process of the pancreas originates
from the superior mesenteric plexus (SMPlx) along the inferior pancreaticoduodenal
artery (IPDA), whereas most nerve fibers going to body and tail of the pancreas originate
from the celiac plexus.[2]
Fig. 1 Animated image showing relevant anatomy of celiac plexus. Reprinted with permission
from Kambadakone et al.[7]
Chemical neurolysis of the celiac plexus is an effective method of controlling pain
that originates from these organs.[3] It has also been reported to be beneficial in managing severe nausea and vomiting
in patients with pancreatic cancer. This has been attributed to sympathetic blockade
causing parasympathetic predominance causing increased gastric motility and peristalsis.[4] Some authors have also reported that celiac plexus neurolysis improves survival
in patients with cancer by reducing opiate requirements, diminishing drug-induced
sedation, and enhancing the ability of patients to perform day-to-day activities that
are necessary to extend life, such as feeding and ambulation.[5]
The block can be guided by anatomical bony landmarks, fluoroscopy, sonography, or
computed tomography (CT). Cross-sectional imaging such as CT and magnetic resonance
imaging (MRI) can reveal soft tissue, especially the celiac plexus.[6] CT is the preferred route due to its wide availability, high contrast, and spatial
resolution. It clearly depicts retroperitoneal structures, and celiac plexus may sometimes
be directly identified. It depicts the exact needle tract and shows diffusion of contrast
mixed neurolytic agents. CT fluoroscopy allows real-time monitoring of the procedure.[7]
Case Details
A 61-year-old man with carcinoma of uncinate process of the pancreas metastatic to
the liver and mediastinum ([Fig. 2]) presented with increasing abdominal pain and opioid dependence. After written informed
consent, clinical workup, and coagulation screen, the patient was taken up for an
ultrasound-guided celiac block with 20 mL of 0.25% bupivacaine and 20 mg of triamcinolone.
Postprocedure, the patient reported suboptimal pain relief with no reduction in opioid
requirement. Owing to the poor acoustic window, proximity of the splenic vein, and
tortuous course of the celiac artery ([Fig. 3A]), the authors decided to do the neurolysis through a posterior approach under CT
guidance. Bilateral paravertebral route seemed rather technically difficult with the
given anatomy; therefore, a paravertebral transaortic route was chosen. A 22G Chiba
needle (Halyard Health Inc.) was used, and its tip was positioned between the celiac
artery and SMA ([Fig. 3C]) and a check injection of 2 mL of a mixture of 0.5 mL nonionic contrast (Iomeron)
diluted with 1.5 mL lignocaine was done. After adequate spread was noted, 15 mL of
mixture of absolute alcohol, bupivacaine, and contrast (in the ratio of 6:3:1) was
injected.
Fig. 2 Axial contrast-enhanced computed tomography (CECT) section of abdomen shows a mass
in the uncinate process (thick arrow) infiltrating the third part of duodenum (A) and chest section (B) showing subcarinal nodal metastatic deposits (thin arrow) with invasion of descending
thoracic aorta.
Fig. 3 Axial images noncontrast computed tomography (NCCT) of the patient in prone position
during procedure showing tortuous course of celiac artery and practically no space
in left side due to IVC (*) and celiac artery (arrow, A). Transaortic needle path on left side was chosen and check injection was done (B) with needle tip between celiac artery and superior mesenteric artery (SMA), better
appreciated on oblique sagittal reformats (C). Alcohol-mixed contrast spread along the SMA noted in sagittal reformatted image
(D).
Check scan showed bilateral spread of the solution around the origin and along the
perivascular sheath of SMA ([Fig. 3D]). The patient reported significant reduction in numerical pain score from 9 to 1
within 45 minutes of procedure. Transient episode of diarrhea lasting less than 24
hours was noted, which is usually expected postsplanchnic sympathicolysis. The patient
did not have any hypotension in postprocedure period and was discharged next day after
an ultrasound check of the abdomen.
Discussion
Celiac plexus is formed by fibers from three prominent ganglions: right celiac, left
celiac, and superior mesenteric ganglion. Superior mesenteric ganglion sends fibers
along the SMA as SMPlx, which supplies the uncinate process portion of the pancreas
and the bowel, jejunum to proximal colon. The patient reported significant relief
despite not having expected periceliac spread probably owing to the site of tumor
in the uncinate process. The ideal needle tip position for celiac plexus neurolysis
is approximately 1 to 2 cm anterior to the aorta, between the diaphragmatic crura
and the pancreas, at the level between the celiac trunk and the SMA.[8]
Ischia et al[9] performed a prospective, randomized study to assess the efficacy of three posterior
approaches for needle celiac plexus block (NCPB), viz. transaortic, classic retrocrural,
and B/L chemical splanchnicectomy, and found no statistically significant difference
in terms of either immediate or up-to-death results. Procedural mortality was nil
with the three techniques and morbidity negligible. The procedure achieved pain relief
in 70 to 80% of patients immediately after the block and in 60 to 75% until death.
Their study showed no increased complications in transaortic approach as is generally
perceived.
The authors' choice of transaortic route in the index case was justified owing to
lack of easy and safe alternative routes in the index case and its established technical
feasibility and safety as mentioned previously. Paravertebral approach was technically
more difficult in this case and would have involved needle coursing through multiple
small venous structures and kidneys. Moreover, a single injection can achieve bilateral
neurolysis, and the volume of drug injected is significantly less than an antecrural
approach.[8]
[10]
