Celiac Plexus and Splanchnic Plexus Nerve Blocks and Neurolytic Procedures

By Bernard Abrams, MD and Kenneth Candido, MD

Posted: 2/19/2010

Regional anesthesia techniques are indicated when pain is unrelieved by the World Health Organization (WHO) hierarchy of pain management, unacceptable side effects with systemic therapies, a pain crisis or crises or a patient’s desire to avoid systemic therapies. (1)

RCT evidence confirms the positive role of neurolytic celiac plexus block with superior results over analgesics alone. A meta-analysis of both controlled trials and reported series found that 59% reported complete relief of pain by 2 weeks and between 73 and 92 % had continued pain relief until death. (2)

A posterior percutaneous, 2-needle technique for celiac plexus and splanchnic nerve blocks was first introduced in 1914 by Kappis, who described it in 1918 in 200 patients and, in the same year, Wendling described with an anterior approach through the liver which rapidly fell into disuse because of the perceived greater risk. Initially used as surgical anesthesia, it fell into disuse with the advent of neuromuscular blocking agents, until the advent of pain management techniques. Gage and Floyd described the use of this technique for acute pancreatitis in 1947. (3)

There are the following approaches to celiac block:

• The classic transcrural approach (Figures 1, 2) using one (shown) or two needles
• Transaortic techniques
  • Fluoroscopically guided transaortic celiac plexus block (Figures 3, 4)
  • CT-Guided Transaortic celiac plexus block (Figures 5, 6)

• Anterior Approaches to Celiac Plexus Block (Figures 7, 8)
  • Percutaneous gangliolysis
  • Intraoperative gangliolysis

In the classic transcrural approach, the goal is to advance the block needles, typically six-inch 22-gauge Quincke type subarachnoid needles, through the crus of the diaphragm at the T12-1 disc level using either CT-scan guidance (Figures 1, 2) or fluoroscopy.

Figure 1

Figure 2

CT scanning has the advantages of precise needle guidance with visualization of the abdominal aorta (not visualized on fluorscopy); the kidneys (not visualized on fluoroscopy); the liver (not visualized on fluoroscopy) and other, contiguous structures. While the visualization is enhanced when using CT scanning, the trade-off is the resultant exposure to much larger doses of ionizing radiation for the patient, up to fifty-times greater than when fluoroscopy is utilized (Figures 3, 4).

Figure 3

Figure 4

However, particularly if the patient has a finite and relatively brief life-expectancy, this exposure to ionizing radiation is likely a moot point. For clarity and resolution of images and structures, there is absolutely no doubt that the CT scan affords a superior imaging technique compared to fluoroscopy. MRI imaging and ultrasound have both been touted as being alternatives to CT scanning, neither of which exposes the patient (or treating staff) to ionizing radiation. However, MRI has not proved to be superior to CT scan either in image quality, nor in ability to visualize contiguous structures. Indeed, even identifying pancreatic structures is not easily accomplished by use of MRI technology. As for ultrasound, the images obtained are typically not useful except perhaps in severely cachetic individuals, to be of any use in driving clinical decision making and in determining the appropriate location for injecting a volume of local anesthetic and/or neurolytic agent.

Again, for the transaortic approach, the CT-scan technique provides more information than does a fluorscopic approach (Figures 3-6).

Figure 5

Figure 6

Not only can the aorta be visualized with CT scanning, the needle can be observed passing through from posterior to anterior until the tip appears at the ventral surface of the external aorta vessel wall. Fluorsocopy is a useful adjunct, however, when seeking to employ the transaortic technique but relies upon the requirement to visualize dripping blood from the proximal hub of the needle for confirmation that the vessel has been punctured. Typically, blood will be observed to merely drip from the needle hub and will not shoot out from a five- or six-inch needle due to the small radius of a 22-gauge needle and the length that a column of blood will need to ascend at normal arterial pressure levels (Hagen–Poiseuille equation: or ?P= 8 µLQ /p r 4 )

Where:
?P is the pressure drop L is the length of needle µ is the dynamic viscosity Q is the volumetric flow rate r is the radius p is the mathematical constant (approximately 3.141592654).

Finally, the anterior approach to celiac plexus block almost exclusively requires CT scan guidance (Figures 7,8) since it is imperative to localize the abdominal aorta and since the fluoroscopic technique typically does not provide sufficient information in this regard to assist the operator.

Figure 7

Figure 8

This approach is ideally suited for individuals who have recently undergone abdominal surgery who may not, due to pain issues, be able to lie prone for even relatively brief periods of time even under the administration of analgesic medications.

The reader is referred to standard texts for details of these blocks. (3), (4)

The technique for splanchnic nerve block generally differs little from the classic retrocrural approach to the celiac plexus. Diagnostic blocks should be performed before ablations with a rapid onset local anesthetic such as 3% lidocaine or 3% 2-chloroprocaine for celiac blocks and 1.5% lidocaine or 3% 2-chloroprocaine for splanchnic blocks. Longer acting drugs such as 0.5% bupivacaine may be used. All drugs should be given in increments because of the danger of neurotoxicity.

Neurolytic blocks may be carried out with ethyl alcohol or aqueous phenol. Alcohol, believed by some to be the superior agent produces severe transient pain and is not miscible with contrast media.. Phenol may be combined with contrast media, a clear advantage.

Serious complications include hypotension, paresthesias of the lumbar somatic nerves, venous or arterial intravascular injection, lumbar somatic nerve injury, subarachnoid or epidural injection, diarrhea, renal injury, paraplegia, pneumothorax, vascular thrombosis or embolism, perforation of the tumor or cysts within the tumor or benign cysts, psoas muscle injury including hematoma, vertebral disc injections, infections (abscess, peritonitis), hematoma in the retroperitoneal space, urinary tract injuries, perioperative and postoperative pain and failure to relieve pain. (3, 4)

References:

1.  Wallace MS, Leung AY, McBeth MD: Malignant pain in Raj PP (ed): Textbook of Regional Anesthesia.P. 582 Churchill Livingstone, Philadelphia.

2.  Eisenbreg E, Carr DB, Chalmers CT 1995 Neurolytic celiac plexus block for treatment of cancer pain-a metaanalysis. Anaesthesia and Analgesia 80:290-295.

3.  Waldman SD, Patt Richard B: Splanchnic and Celiac Plexus Nerve Block p. 1265 in Waldman SD (ed) Pain Management Saunders Elsevier 2007 Philadelphia.

4.  De Leon-Casasola, ONeurolysis of the Sympathetic Axis for Cancer Pain Management p. 917 In Benzon HT (ed) Raj’s Practical Management of Pain, Fourth Edition Mosby Elsevier 2008 Philadelphia.