Celiac Plexus Block and Neurolysis



Celiac Plexus Block and Neurolysis





Overview

Neurolytic celiac plexus block (NCPB) is among the most widely applicable of all neurolytic blocks. NCPB has a long-lasting benefit for 70% to 90% of patients with pancreatic and other intra-abdominal malignancies. Several techniques have been described for localizing the celiac plexus. The classic technique employs a percutaneous posterior approach, using surface and bony landmarks to position needles in the vicinity of the plexus. Numerous reports have described new approaches for celiac plexus block (CPB), using guidance from plain radiographs, fluoroscopy, computed tomography (CT), or ultrasound. No single methodology has proven clearly superior in either its safety or its success rate. In more recent years, it has been generally agreed that radiographic guidance is necessary to perform CPB. Many practitioners have turned to routine use of CT, taking advantage of the ability to visualize adjacent structures when performing this technique.


Anatomy

The celiac plexus is comprised of a diffuse network of nerve fibers and individual ganglia that lie over the anterolateral surface of the aorta at the T12/L1 vertebral level. Sympathetic innervation to the abdominal viscera arises from the anterolateral horn of the spinal cord between the T5 and T12 levels. Nociceptive information from the abdominal viscera is carried by afferents that accompany the sympathetic nerves. Presynaptic sympathetic fibers travel from the thoracic sympathetic chain toward the ganglion, traversing over the anterolateral aspect of the inferior thoracic vertebrae as the greater (T5 to T9), lesser (T10 to T11), and least (T12) splanchnic nerves (Fig. 11-1). Presynaptic fibers traveling via the splanchnic nerves synapse within the celiac ganglia over the anterolateral surface of the aorta surrounding the origin of the celiac and superior mesenteric arteries at approximately the L1 vertebral level. Postsynaptic fibers from the celiac ganglia innervate all the abdominal viscera, with the exception of the descending colon, sigmoid colon, rectum, and pelvic viscera.

CPB using a transcrural approach places the local anesthetic or neurolytic solution directly on the celiac ganglion anterolateral to the aorta (see Fig. 11-1). The needles pass directly through the crura of the diaphragm en route to the celiac plexus. Spread of the solution toward the posterior surface of the aorta may thus be limited, perhaps reducing the chance of spinal nerve or spinal segmental artery involvement. In contrast, splanchnic nerve block (see Fig. 11-1) avoids the risk of penetrating the aorta and uses smaller volumes of solution, and the success is unlikely to be affected by anatomic distortion caused by extensive adenopathy or tumor within the pancreas. Because the needles remain posterior to the diaphragmatic crura in close apposition to the T12 vertebral body, this has been termed the retrocrural technique. Splanchnic nerve block is a minor modification of the classic retrocrural CPB; the only difference being that for splanchnic block, the needles are placed over the midportion of the T12 vertebral body rather than over the cephalad portion of L1. Retrocrural CPB at the superior aspect of the L1 vertebral body and splanchnic nerve block at the mid T12 vertebral body have both been described, and they are essentially the same technique, relying on cephalad spread of solution to block the splanchnic nerves in a retrocrural location.
In most cases, celiac plexus (transcrural or retrocrural) and splanchnic nerve block can be used interchangeably to affect the same results. Although there are those who strongly advocate one approach over the other, there is no evidence that either results in superior clinical outcomes.






Figure 11-1. Anatomy of the celiac plexus and splanchnic nerves. The celiac plexus is comprised of a diffuse network of nerve fibers and individual ganglia that lie over the anterolateral surface of the aorta at the T12/L1 vertebral level. Presynaptic sympathetic fibers travel from the thoracic sympathetic chain toward the ganglion, traversing over the anterolateral aspect of the inferior thoracic vertebrae as the greater (T5 to T9), lesser (T10 to T11), and least (T12) splanchnic nerves. CPB using a transcrural approach places the local anesthetic or neurolytic solution directly on the celiac ganglion anterolateral to the aorta. The needles pass directly through the crura of the diaphragm en route to the celiac plexus. In contrast, for splanchnic nerve blocks, the needles remain posterior to the diaphragmatic crura in close apposition to the T12 vertebral body. Shading indicates the pattern of solution spread for each technique.


Patient Selection

Celiac plexus and splanchnic nerve block are used to control pain arising from intra-abdominal structures. These structures include the pancreas, liver, gall bladder, omentum, mesentery, and alimentary tract from the stomach to the transverse colon. The most common application of NCPB is to treat pain associated with intra-abdominal malignancy, particularly pain associated with pancreatic cancer. Neurolysis of the splanchnic nerves or celiac plexus can produce dramatic pain relief, reduce or eliminate the need for supplemental analgesics, and improve quality of life in patients with pancreatic cancer and other intra-abdominal malignancies. The long-term benefit of NCPB in patients with chronic nonmalignant pain, particularly those with chronic pancreatitis, is debatable.



Level of Evidence








Quality of Evidence and Grading of Recommendation






















Grade of Recommendation/Description


Benefit vs. Risk and Burdens


Methodological Quality of Supporting Evidence


Implications


RECOMMENDATION: Celiac plexus block (CPB) for pain secondary to pancreatic cancer. Neurolytic CPB should be used for reduction of abdominal pain and reducing opioid-related side effects in patients with pain associated with pancreatic cancer. Treatment may be more effective in those with early malignancy and those with tumor located in the head of the pancreas when compared with the body of tail of the gland.


1A/strong recommendation, high-quality evidence


Benefits clearly outweigh risk and burdens, or vice versa


I: Randomized controlled trials (RCTs) without important limitations or overwhelming evidence from observational studies


Strong recommendation, can apply to most patients in most circumstances without reservation


RECOMMENDATION: Celiac plexus block (CPB) for pain secondary to chronic pancreatitis. CPBs using local anesthetics may be used for the treatment of pain secondary to chronic pancreatitis.


2C/weak recommendation, low-quality or very low-quality evidence


Uncertainty in the estimates of benefits, risks, and burden; benefits, risk, and burden may be closely balanced


II-2: Observational studies or case series


Very weak recommendations; other alternatives may be equally reasonable


The use of NCPB using alcohol or phenol to treat abdominal pain associated with intra-abdominal malignancy, particularly pain associated with pancreatic cancer, has shown considerable benefit in controlled trials. The use of CPB using local anesthetic solutions with or without corticosteroids for treating pain secondary to chronic pancreatitis is less well studied, but observational trials suggest intermediate-term pain reduction in some patients.

A 2011 Cochrane Library Review examined the available evidence for use of CPB for pancreatic cancer pain in adults and concluded, “Although statistical evidence is minimal for the superiority of pain relief over analgesic therapy, the fact that CPB causes fewer adverse effects than opioids is important for patients.” The American Society of Anesthesiologists (ASA) Task Force on Chronic Pain Management published a 2010 Practice Guideline, offering the following recommendation regarding the use of CPBs for the treatment of pain associated with chronic pancreatitis: “Studies with observational findings report that celiac plexus blocks can provide pain relief for 25-50% of patients with pancreatitis for assessment periods ranging from 1 to 6 months.”

While there is strong support from controlled trials for the use of NCPB for treating pain due to pancreatic cancer, significant questions remain. There are numerous methods for performing this block, including the fluoroscopic and CT-guided techniques described here as well an endoscopic, transgastric, ultrasound-guided technique performed primarily by gastroenterologists. There is little information to guide choice among the various approaches. Likewise, the use of both alcohol and phenol as neurolytic agents remains common, and there is no evidence that one agent is superior to the other. Finally, the use of local anesthetic alone and anesthetic and steroid combinations has been reported in the treatment of pain associated with chronic pancreatitis, and there is little scientific study to guide choice between the two. However, the use of particulate steroid in this region should be untaken with great caution, as the arterial supply to the spinal cord lies in close proximity to the site of injection and placement of particulate steroid into a critical reinforcing artery to the spinal cord is likely to lead to catastrophic spinal cord infarction.


Positioning

The patient lies prone with the head turned to one side (Fig. 11-2). The C-arm is centered over the thoracolumbar junction. The final needle position for CPB is over the anterolateral surface of the aorta, just anterior to the T12/L1 junction. The C-arm is rotated obliquely 20 to 30 degrees, until the tip of the transverse process of L1 overlies the anterolateral margin of the L1 vertebral body (Fig. 11-3). The final needle position for splanchnic nerve block is anterolateral to the T12 vertebral body; thus, cephalad angulation of the C-arm is also needed to bring the inferior margin of the 12th rib cephalad to the T12 vertebral body (see Fig. 11-2).


Block Technique


Celiac Plexus Block (Transcrural Technique)

Once the C-arm is aligned, the skin and subcutaneous tissues overlying the superior margin of the L1 vertebral body are anesthetized with 1 to 2 mL of 1% lidocaine. The aorta lies to the left of midline over the vertebral bodies.
By routinely placing the left-sided needle first, a single needle can often be used for the block (see Fig. 11-3). If the aorta is penetrated en route, a transaortic technique is employed. A 22-gauge, 5-inch spinal needle (8 inch for the obese patient) is advanced just caudal to the margin of the 12th rib and cephalad to the transverse process of L1 toward the anterolateral surface of the L1 vertebral body. The needle is advanced, using repeat images every 1 to 2 cm of advancement to ensure the needle remains coaxial until the needle contacts the anterolateral margin of L1. The C-arm is then rotated to a lateral projection, and the needle is advanced to lie 2 to 3 cm anterior to the anterior margin of L1 in the lateral view (Fig. 11-4). Continuous aspiration should be applied as the needle is advanced anterior to the anterior border of L1. If blood appears, the needle has penetrated the aorta and should be advanced through the anterior wall of the aorta, until blood can no longer be aspirated. The needle tip should be medial to the lateral border of the L1 vertebral body in the anterior-posterior (AP) view (Fig. 11-5). Final needle position is confirmed by injecting 1 to 2 mL of radiographic contrast (iohexol 180 mg per mL) under live fluoroscopy. The contrast should layer over the anterior surface of the aorta (see Fig. 11-4

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May 26, 2016 | Posted by in ANESTHESIA | Comments Off on Celiac Plexus Block and Neurolysis
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