Chapter 71 Neurolytic Visceral Sympathetic Blocks

Question 1

Pain associated with cancer may be

Answer 1

somatic, visceral, and neuropathic in origin, and about 50% of all cancer patients have a combination of pain types at the time of diagnosis.

Question 2

When visceral structures are stretched, compressed,

invaded, or distended,

Answer 2

a poorly localized noxious pain is reported.

Question 3

Patients experiencing visceral pain often describe the pain as

Answer 3

vague, deep, squeezing, crampy, or colicky in nature.

Question 4

referred pain

Answer 4

shoulder pain that appears when the diaphragm is invaded with tumor, and nausea/ vomiting

Question 5

Visceral pain associated with cancer may be relieved

with oral pharmacologic therapy that include

Answer 5

combinations of nonsteroidal anti-inflammatory agents, opioids, and coadjuvant therapy. Neurolytic blocks of the sympathetic axis are also extremely effective in controlling visceral cancer pain.

Question 6

neurolysis of the sympathetic axis should be judged as an important adjunct to pharmacologic therapy for the relief of severe pain experienced by cancer patients. As such, these blocks can rarely eliminate cancer pain, because

Answer 6

patients also frequently experience coexisting somatic and neuropathic pain.

Question 7

The goal of performing a neurolytic block of the sympathetic axis is to

Answer 7

(1) maximize the analgesic effect of opioid and nonopioid analgesics, and
(2) reduce the dosage of these agents to alleviate untoward side effects.

Question 8

The celiac plexus is situated

Answer 8

retroperitoneally in the upper abdomen. It is at the level of the T12 and L1 vertebrae, anterior to the crura of the diaphragm. It surrounds the abdominal aorta and the celiac and superior mesenteric arteries. The plexus continues inferiorly to form the superior and the inferior mesenteric plexus

Question 9

celiac plexus is composed of a network of nerve

fibers, both from the

Answer 9

sympathetic and parasympathetic systems. It contains one to five large ganglia, which receive sympathetic fibers from the three splanchnic nerves (greater, lesser, and least). The thoracic splanchnic nerves lie above and posterior to the diaphragm, anterior to the
T12 vertebra.

Question 10

The celiac plexus also receives parasympathetic

fibers from the

Answer 10

vagus nerve, and provides autonomic supply to the liver, pancreas, gallbladder, stomach, spleen,
kidneys, intestines, and adrenal glands, as well as to the
blood vessels.

Question 11

Neurolytic blocks of the celiac plexus have been used for

Answer 11

malignant and chronic nonmalignant pain. In patients with acute or chronic pancreatitis it has been used with significant success. Likewise, patients with cancer in the upper abdomen who have a significant visceral pain component have responded well to this block

Question 12

celiac plexus block—multiple posterior percutaneous approaches to block nociceptive impulses from the viscera of the upper abdomen.

Answer 12

the classic retrocrural approach, block of the splanchnic nerves, the anterocrural (or transcrural) approach, and the transaortic approach.

Question 13

Celiac Plexus Block

the common posterior approaches

Answer 13

the two needles are inserted at the level of the first lumbar vertebra, 5 to 7 cm from the midline. The tip of the needle is then directed toward the body of L1 for the retrocrural and anterocrural approaches and to the body of T12 for neurolysis of the splanchnic nerves. The left needle is positioned just posterior to the aorta and the right needle is advanced 1 cm deeper with a retrocrural or splanchnic nerve approach. Fluoroscopy reveals spread of contrast anterior to the vertebral body and posterior to the diaphragm. The needles must be advanced through the diaphragm using the anterocrural approach. This is relatively easy on the right side, but more difficult on the left side, because of the position of the aorta.

Question 14

the common posterior approaches relatively easy on the
right side, but more difficult on the left side, because of
the position of the aorta. Two solutions have been described:

Answer 14

confirmation with computed tomography (CT) scan and use of a single-needle, transaortic injection on the left side. The left needle is inserted closer to the midline and placed anterolateral to the aorta with CT
scan, or into and through the aorta with the transaortic
approach

Question 15

DRUG AND DOSING For neurolytic blocks

Answer 15

50% to 100% alcohol, 20 ml per side, is utilized

Question 16

When injected by itself, alcohol can produce severe pain. Thus, it is recommended to

Answer 16

first inject 5 to 10 ml of 0.25% bupivacaine 5 min prior to
the injection of alcohol, or to dilute 100% alcohol by 50%
with local anesthetic (0.25% bupivacaine).

Question 17

Phenol

Answer 17

in a 10% final concentration may also be used, and it has the advantage of being painless on injection. Both agents appear to have the same efficacy.

Question 18

Complications associated with celiac plexus blocks

Answer 18

appear to be related to the technique used: retrocrural, transcrural, or transaortic.Orthostatic hypotension transient diarrhea paraplegia and bladder and bowel dysfunction

Question 19

Orthostatic hypotension management

Answer 19

bed rest, avoidance of sudden changes in position, and fluid replacement. Once compensatory vascular reflexes are fully activated, this side effect disappears. Wrapping of the lower extremities from the toe to the upper thighs with elastic bandages has been used with success in patients who developed orthostatic hypotension and needed to ambulate during the first week after the block

Question 20

Backache may result from

Answer 20

(a) local trauma during the needle placement resulting in a retroperitoneal hematoma, (b) alcohol irritation of the retroperitoneal structures, or (c) injury to the lumbar plexus

Question 21

Patients with a backache should have at least two

Answer 21

hematocrit measurements at a 1-hour interval. If there is a decrease in the hematocrit, radiologic imaging is indicated to rule out a retroperitoneal hematoma.

Question 22

A urine analysis positive for red cells suggests

Answer 22

renal injury

Question 23

Retroperitoneal hemorrhage

Answer 23

Patients who present with backache and orthostatic hypotension after a celiac plexus block should be admitted to the hospital for serial hematocrit monitoring. If a low or a decreasing hematocrit is demonstrated, patients should undergo radiologic evaluation to rule out injury to the kidneys, the aorta, or other vascular structures. A surgical consult should be obtained as soon as feasible

Question 24

Diarrhea may occur due to

Answer 24

sympathetic block of the bowel. Treatment includes hydration and antidiarrheal agents. Oral loperamide is a good choice, although any anticholinergic may be used.

Question 25

Abdominal aortic dissection

Answer 25

The mechanism of aortic injury is direct damage with the needle during the performance of the block. As expected, the anterocrural approach is more frequently associated with this complication. Thus, if there were evidence of atherosclerotic disease of the abdominal aorta, it would seem appropriate to avoid this approach

Question 26

Paraplegia and transient motor paralysis have

occurred after celiac plexus block

Answer 26

these neurologic complications may occur due to spasm of the lumbar segmental arteries that
perfuse the spinal cord.

Question 27

How to Avoid Paraplegia and transient motor paralysis have occurred after celiac plexus block.

Answer 27

it may be empirically suggested that alcohol should not be used if there is evidence of significant atherosclerotic disease of the aorta, suggesting that the circulation to the spinal cord may also be impaired. However, there is also a report of paraplegia after phenol use, suggesting that other factors, such as direct vascular or neurologic injury or retrograde spread to the spinal cord, may come into play.

Question 28

there is evidence to suggest that chronic use of high doses of opioids may have a negative effect on immunity. Thus, analgesic techniques that lower opioid consumption

Answer 28

should have positive effects on patient outcomes

Question 29

SUPERIOR HYPOGASTRIC PLEXUS

BLOCK indication

Answer 29

pelvic pain associated with cancer and that seen

with chronic nonmalignant conditions

Question 30

Analgesia to the organs in the pelvis is possible with superior hypogastric plexus because

Answer 30

the afferent fibers innervating these structures travel with the sympathetic nerves, trunks, ganglia, and rami and are accessible for neurolytic block. Thus, a sympathectomy for visceral pain is analogous to a peripheral neurectomy or dorsal rhizotomy for somatic pain.

Question 31

The superior hypogastric plexus is situated in

Answer 31

the retroperitoneum, bilaterally, extending from the lower third of the fifth lumbar vertebral body to the upper third of the first sacral vertebral body.

Question 32

SUPERIOR HYPOGASTRIC PLEXUS BLOCK TECHNIQUE

Answer 32

Patients are placed in the prone position with a pillow
under the pelvis to flatten the lumbar lordosis. Local infiltration of the intervening muscle planes can be performed. Needle insertion sites are 5 to 7 cm lateral to the midline, depending on patient’s height and girth, at the level of the L4–L5 interspace. Two 7- to 9-inch, 22-gauge short beveled needles are inserted with the bevel directed medially, 45 degrees mesiad and 30 degrees caudad, so that the needle tips lie anterolateral to the L5–S1 intervertebral space. Aspiration is important to avoid injection into the iliac vessels. If blood is aspirated, a transvascular approach can be used.

Question 33

SUPERIOR HYPOGASTRIC PLEXUS BLOCK TECHNIQUE

Answer 33

Biplanar fluoroscopy is used to verify accurate needle
placement. Anteroposterior (AP) views should reveal
the tip of the needle at the level of the junction of the
L5 and S1 vertebral bodies. Lateral views will confirm
placement of the needle tip just beyond the vertebral
body’s anterolateral margin. The injection of 2 to 3 ml
of water-soluble contrast medium is used to verify
accurate needle placement and to rule out intravascular
injection. In the AP view, the spread of contrast should
be confined to the midline region. In the lateral view, a
smooth posterior contour corresponding to the anterior
psoas fascia indicates that the needle is at the appropriate depth.

Question 34

SUPERIOR HYPOGASTRIC PLEXUS BLOCK DRUG AND DOSING

Answer 34

For a prognostic hypogastric plexus blockade; a volume
of 6 to 8 ml of 0.25% bupivacaine through each needle
is recommended. For therapeutic purposes, a total of 6 to 8 ml of 10% aqueous phenol or 80% alcohol can be
injected through each needle

Question 35

SUPERIOR HYPOGASTRIC PLEXUS BLOCK COMPLICATIONS

Answer 35

Potential complications include retroperitoneal hematoma formation and acute ischemia of the foot, due to the dislodgement of an atherosclerotic plaque from the iliac vessels

Question 36

Ganglion Impar

Answer 36

solitary retroperitoneal structure located at the level of the sacrococcygeal junction. This ganglion marks the end of the two sympathetic chains

Question 37

effectively treated with neurolysis of the
ganglion impar (the ganglion of Walther)

Answer 37

Visceral pain in the perineal area associated with malignancies

Question 38

Patients who will benefit from this ganglion impar blockade will frequently present with

Answer 38

vague and poorly localized pain, which is burning in
character and frequently accompanied by sensations of
urgency.

Question 39

GANGLION IMPAR BLOCK

TECHNIQUE

Answer 39

This block may be performed with the patient in the left
lateral decubitus position with the knees flexed, in the
lithotomy position, or in the prone position. The initial
technique employs a 22-gauge, 3.5-inch spinal needle that is manually bent to facilitate placement of the needle tip anterior to the concavity of the sacrum and coccyx. The needle is introduced through the anococcygeal ligament with its concavity oriented posteriorly and, under fluoroscopic guidance, is directed along the midline to contact bone at or near the sacrococcygeal junction. Contrast dye confirms retroperitoneal spread; on the lateral view, it is shaped like a comma.

Question 40

GANGLION IMPAR BLOCK
TECHNIQUE
transcoccygeal approach

Answer 40

performed with the patient in the prone position. This approach has been reported to be both effective and safe. A 20-gauge, 1.5-inch needle is inserted through the sacrococcygeal ligament in the midline. The needle is then advanced until the tip is placed posterior to the rectum. For diagnostic blocks, 4 to 8 ml of 1% lidocaine or 0.25% bupivacaine is selected; for neurolytic block, 4 (to 8) ml of 10% phenol is used. Although the technique is relatively straightforward, care is needed to prevent perforation of the rectum and injection into the periosteum.

Question 41

Neurolysis of the sympathetic axis is a safe and costeffective way to treat

Answer 41

visceral pain associated with cancer

Question 42

Neurolysis of the sympathetic axis benefits

Answer 42

not limited to improved analgesia but also include a decrease in opioid consumption.