Chapter 79 Peripheral Sympathetic Blocks Flashcards Preview

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Flashcards in Chapter 79 Peripheral Sympathetic Blocks Deck (70):

indications for sympathetic blockade

Sympathetic blocks can be used for diagnostic, prognostic, and therapeutic purposes. Diagnostic blocks are done to determine if the pain is sympathetically mediated or not. Prognostically, the blocks are done to determine if neurolysis or surgical sympathectomy could be beneficial. Finally, therapeutic blocks (usually in a series with local anesthetics) are done to treat conditions such as complex regional pain syndromes (CRPSs), phantom limb pain,1 postherpetic
neuralgia, and ischemic and cancer pain


The cervical sympathetic trunk contains three interconnected

the superior, middle, and inferior cervical ganglia


In 80% of people the lowest cervical ganglion is
fused with the first thoracic ganglion to form

cervicothoracic (stellate) ganglion. If not connected, the first thoracic ganglion is labeled as the stellate ganglion. The
ganglion is oval shaped and measures 2.5 cm long, 1 cm
wide, and 0.5 cm thick


The cervical ganglia receive preganglionic fibers from

the lateral gray column of the spinal cord; the myelinated
preganglionic cell axons originate from the anterolateral horn of the spinal cord.


The nerve fibers emerge from

the upper thoracic spinal cord through the ventral spinal root,
joining the spinal nerves at the start of the ventral rami.
They leave the spinal nerve through the white rami
communicantes, which enter the corresponding thoracic
ganglia, through which they ascend into the neck.


The preganglionic fibers for the head and neck emerge from

upper five thoracic spinal nerves (mainly the upper three), ascending in the sympathetic trunk to synapse in the cervical


The preganglionic fibers supplying the upper limb originate from

the upper thoracic segment, probably T2–T6; ascend via the sympathetic trunk to synapse in the
cervicothoracic ganglion, where postganglionic fibers pass to the brachial plexus


The white ramus to the cervicothoracic ganglion

most of the preganglionic fibers for the head and neck; these ascend the trunk to the superior cervical ganglion from which postganglionic branches supply vasoconstrictor and sudomotor nerves to the face and neck, secretory fibers to the salivary glands, dilator
pupillae, and nonstriated muscle in the eyelid and orbitalis


Blockade of the white ramus to the cervicothoracic ganglion

leads to Horner’s syndrome


(Horner’s syndrome

ptosis, miosis, enophthalmos, and loss of sweating of the face and neck.


The cervicothoracic ganglion
sends gray ramus communicantes to

the seventh and
eighth cervical and first thoracic nerves and gives off a
cardiac branch, branches to nearby vessels, and sometimes a branch to the vagus nerve.


To achieve successful sympathetic denervation of the
head and neck, one should block

the stellate ganglion
because all preganglionic nerves either synapse or pass
through the ganglion on their way to the more cephalad ganglia.


Blood vessels of the upper limb beyond the first part of the axillary artery receive their sympathetic supply via

branches of the adjacent brachial plexus


first and second (and occasionally the third) intercostal nerves may be interconnected by

postganglionic fibers from their gray rami; these fibers provide another pathway by which postganglionic nerves pass from the upper thoracic ganglia to the brachial plexus. These anomalous pathways have been termed Kuntz’s nerves and are implicated in cases of inadequate relief of sympathetic mediated pain despite evidences of cervical
ganglia block


The cervical sympathetic chain

lies anterior to the prevertebral fascia. It is enclosed within the lateral aspect of the alar fascia (the thin layer of fascia immediately anterior to the prevertebral fascia that separates the cervical sympathetic chain from the retropharyngeal space). It is medial to the carotid sheath.


The carotid
sheath is connected to

the alar fascia by a variable
mesothelium-like fascia.


The fascial plane enclosing the
cervical sympathetic chain may be in direct communication with several spaces including

the space in front of the scalenus anterior muscle, the brachial plexus, spinal nerve roots, the prevertebral portion of the vertebral artery, and between the endothoracic fascia and the thoracic
wall muscle at the T1–T2 level. These communications
may explain some of the side effects of stellate ganglion block.


In the upper thorax the thoracic sympathetic
chain lies lateral to the

longus colli muscle and
posterior to the endothoracic fascia, which is the inferior continuation of the prevertebral fascia. The cervicothoracic ganglion lies on or just lateral to the longus colli muscle between the base of the seventh cervical transverse process and the neck of the first rib (which are posterior to the ganglion), the vertebral vessels are anterior, and the nerve roots that contribute to the inferior portion of the brachial plexus are posterior to the ganglion.


The vertebral artery

originates from the subclavian artery, passes anterior to the ganglion at C7 and enters the vertebral foramen, posterior to
the anterior tubercle of C6 in 90% of cases


Potential Indications for Stellate Ganglion

Complex regional pain syndrome, types I and II
Vascular insufficiency–Raynaud’s syndrome, vasospasm, vascular disease
Accidental intra-atrial injection of drug
Postherpetic neuralgia and acute herpes zoster
Phantom pain
Complex regional pain syndrome, breast and postmastectomy pain
Quinine poisoning
Hyperhidrosis of upper extremity
Cardiac arrhythmias
Vascular headaches
Neuropathic pain syndromes including central pain
Cancer pain
Facial pain—atypical and trigeminal neuralgia
Hot flashes



Surface Landmark (Non–Image Guided) TECHNIQUE

Positioning and Landmarks

the patient is positioned supine with the neck slightly extended. A small shoulder roll may be placed but is not necessary. The mouth can be slightly opened to relax the neck muscles. The cricoid cartilage is palpated to
find the C6 level and, more specifically, the transverse
process. The skin crease just caudal to the thyroid may be
helpful as it is found to cross the C6 transverse process in
71% of cases. The Chassaignac’s tubercle at C6 is identifiedwith palpation. he carotid is retracted slightly laterally while local anesthetic is placed intradermally with a 27-gauge needle. This is followed by the placement of either 22-gauge Quincke or pencil-point needle perpendicularly in an anterior to posterior fashion until the needle contacts bone and then withdrawn 2 mm. After negative aspiration, 0.5 to 1 ml of local anesthetic is
injected slowly while the patient is awake and responsive to detect aberrant spread of the local anesthetic to surrounding structures. If negative, 5 to 8 ml of 0.25% bupivacaine is injected incrementally with frequent aspiration. The patient is then monitored for a minimum of 30 min to assess response to the blockade.


In most individuals, the Chassaignac’s tubercle is

approximately 3 cm cephalad to the sternoclavicular
joint at the medial border of the sternocleidomastoid


The trachea and carotid pulse is palpated gently by

placing the index and middle fingers between the sternocleidomastoid
muscle and the trachea.


Fluoroscopic Technique:

Once the patient is in proper position, the fluoroscope is
brought in and a posteroanterior image is taken. The vertebrae are counted and both the C6 and C7 levels are
noted along with the trachea. The C7 level is preferred because of its closer proximity to the stellate ganglion, but the vertebral artery is uncovered at this level unlike at the C6 level where the vertebral artery travels posterior to Chassaignac’s tubercle. If the C7 level is the final location of the needle tip, then it is important to keep the needle more medial on the transverse process to avoid the vertebral artery. After local anesthetic infiltration, a 25- or 22-gauge 1.5- or 2-inch needle is advanced coaxially to the anterior transverse process of the chosen level.Once contact is made, the needle is withdrawn 2 mm so that it is not in contact with periosteum. A lateral image maybe taken to confirm that the needle is anterior to the vertebral body,
but is not always necessary. A pre-contrast flushed extension
set is connected to the needle and, after negative aspiration for blood, under live, real-time fluoroscopy, or digital subtraction angiography, 1 to 5 ml of contrast is injected. The optimal spread of contrast should cover the C6–T2 levels to ensure blockade of the stellate ganglion. A test dose is then injected with 0.5 to 1 ml of
1% lidocaine through the extension tubing (to minimize
needle movement) assuring that the local anesthetic passes
through the tubing. After a negative test dose, ~ 5 to 10 ml of local anesthetic is injected incrementally


The greater the volume injected,
the greater the likelihood of

spread to the recurrent laryngeal nerve, phrenic nerve, or brachial plexus. It is important to intremittently aspirate during the injection.



Other Fluoroscopic Approaches

The head is then turned to the side opposite to be blocked. The fluoroscope is brought in to demarcate the C5–C6 disc on AP view. The C-arm is then rotated ipsilateral oblique until the foramina are clearly demarcated. The target of the injection is the junction of the uncinate process and the vertebral body of C7. A 25-gauge needle is then passed coaxially with the fluoroscope beam until it reaches the target. As with all image-guided procedures, it is important to keep the needle coaxial and, in this case, avoid the needle going posterior into the foramina (direct entry into the thecal sac). Once contact with bone occurs, the stylet is removed and contrast is injected as described above in the previous section. Three to 5 ml of local anesthetic is all that is needed to block the stellate ganglion with this technique



Other Fluoroscopic Approaches

advantage of the technique

the needle is placed obliquely to allow for placement at C7 while avoiding the vertebral artery (which is anterior to the stellate ganglion) and the pleural dome in non-emphysematous patients.

l Eliminates pushing away vasculature and pressing on
the potentially painful Chaissagnac’s tubercle
l Minimizes the chance of intravascular injection
l Minimizes esophageal perforation
l Minimizes the chance of recurrent laryngeal nerve
l Reduces the volume of local anesthetic
l Easy to teach trainees



Ultrasound Approach

A linear-array, 3- to 12-MHz frequency probe is placed transversely at the level of C6, just lateral to the trachea. Fluoroscopy may be utilized initially to identify the C6 level. Under real-time ultrasound
imaging, 5 ml of 0.25% bupivicaine were injected in
divided doses demonstrating excellent caudal and cephalad
spread. Appropriate sympathetic blockade was monitored and achieved based on the presence of Horner’s syndrome and increased extremity temperature without recurrent laryngeal nerve blockade.



Posterior Approach:

The patient is in the prone position, and image guidance
is an absolute necessity (usually fluoroscopy, but CT
can be utilized). The fluoroscope is utilized to obtain AP images of the T2 and T3 vertebrae. The C-arm is then
rotated obliquely until the transverse process is just over
the vertebral body followed by cephalocaudal rotation
until the first rib is squared off. The target is then the midpoint of the T2 and/or the T3 vertebra. A less oblique
angle can also be used if there is concern for pneumothorax,
but may make it more difficult to pass the needle adjacent
to the vertebral body. Strict coaxial technique must
be used to minimize complications and the final needle position is determined. After the needle is in the correct position, 0.5 to 3 ml of contrast is injected under real-time imaging or digital subtraction angiography to observe for vascular uptake or extraneous spread. Five milliliters of local anesthetic is then injected in divided doses and the patient is monitored for sympathetic blockade.



Posterior Approach:


there is a failure of achieving sympathetic blockade
of the upper extremity or when the block is done as a precursor
to percutaneous or surgical sympathectomy. Some
advocate that this approach should be utilized for all upper extremity sympathectomies



Volumes of Injectate:

the blind paratracheal approach at C6 and found that 5 ml of injectate almost always demonstrated spread over the C6–T2 levels without spread ventrally or laterally, whereas 10 and 20 ml of injectate almost always spread to other spaces which can cause recurrent laryngeal nerve and/or phrenic nerve blockade


lumbar sympathetic chain consists of

four to five paired ganglia that lie along the anterolateral surface of the lumbar vertebral bodies with the psoas muscle and fascia separating the sympathetic nerves from the somatic nerves.


The lumbar sympathetic chain contains

pre- and
post-ganglionic fibers to the pelvis and lower extremities


the best site for placement of the
tip of the needle

the anterolateral surface of the lower third of the second vertebral body or at the upper third of the third vertebral body since all of the sympathetic
fibers from the lower extremity pass through the L2 and
L3 ganglion.


The segmental artery and vein
pass along

the midportion of the lumbar vertebral body in
a tunnel under the dense fascia



Complex regional pain syndrome, types I and II
Phantom pain
Arterial insufficiency of lower extremity
Raynaud’s syndrome
Acute herpes zoster
Lower extremity crush




done blindly by starting 5 to
8 cm lateral to the spinous processes of L2–L4 and using
contact with the transverse process as a gauge of depth
and then walking anteriorly off of the vertebral body



Fluoroscopic Approach (Paradiscal):

The patient is positioned prone. The fluoroscope is
brought in to identify the L2, L3, and L4 levels. The fluoroscope is angulated cephalocaudad to square off the L2–L3 disc space, and the fluoroscope is rotated ipsilateral oblique 20 to 30 degrees so that the transverse process of L3 is visualized
over the vertebral body. The target is at the anterosuperior
portion of L3 or anteroinferior portion of L2 (hence the term “paradiscal”). After local anesthetic infiltration, a
22-gauge by 5-to-7 inch needle is advanced coaxially with the beam of the fluoroscope until it make contact with the vertebral body.The fluoroscope is then rotated to AP view to confirm
that the needle is contacting the vertebral body and not
the transverse process or entering the intervertebral
disc. The fluoroscope is then rotated to the lateral view
and the needle tip is walked anteriorly to the anterior onethird of the vertebral body, or, if needed, to the anterior
portion of the vertebral body. Once proper location is
identified, 1 to 5 ml of contrast is injected under real time
fluoroscopy to confirm correct placement. Once the needle is in an appropriate place, 5 to 20 ml of local anesthetic is injected incrementally.



Common errors
in needle location include

placement of needle within
the psoas muscle or incorrect fascial plane of the needle. If
the needle is advanced too anteriorly, the aorta may be
pierced; if too posteriorly, the block may be unsuccessful




The benefits of this technique include

decreased incidence
of genitofemoral neuritis, decreased incidence of
injuring lumbar arteries, closer proximity to the ganglia, decreased scarring of the paravertebral muscles (for
repeated neurolysis), and decreased spread of contrast to the psoas muscle (relative to the blind approach).




similar to performing a discography using
either a single or double needle technique, except that the final needle position is anterior to the disc rather than in the middle of the disc.



Percutaneous neurolysis has been performed successfully
for both the stellate ganglion and the lumbar sympathetics. The two options for neurolysis are radiofrequency
(RF) (pulsed and thermal) versus chemical (phenol and alcohol).


Radiofrequency techniques allow for

for more controlled lesions


chemical lesions may
allow for

larger lesions, and are dependent on the
volume of agent injected.



At the stellate or lumbar levels, 2 to 3 ml of phenol (3%–6%) or alcohol (50%–100%) is injected to minimize spread to adjacent structures.


Phenol is usually the agent of
choice because

of a decrease in incidence of neuritis post procedure. The usual concentration of phenol is 6%


Neurolysis at the stellate level can be done

similar to the anterior approach at C6 or C7, or can be done via the posterior approach at T2 or T3 for upper extremity problems


A test dose of local anesthetic should be injected prior to a
chemical neurolysis to ensure

a negative motor and sensory block prior to the injection of the neurolytic agent


Radiofrequency lesioning

more controlled method
of neurolysis as the only areas lesioned are at the tip of
the needle.


Options of Radiofrequency lesioning include

a nondestructive pulsed lesion
or a more conventional, destructive thermal lesion


The RF needle can be electrically stimulated prior to lesioning, this helps to

avoid lesioning of unwanted surrounding structures
such as the recurrent laryngeal nerve or genitofemoral nerve


RF lesion of the stellate ganglion at the C7 level

For RF lesion of the stellate ganglion at the C7 level, then
stimulation can be done while the patient says “EE” to see
if there is any stimulation of the recurrent laryngeal nerve as well as phrenic nerve. A 22-gauge cannula with 50-mm
length and 5-mm active tip, is utilized and performed similarly
to the anterior approach as described above, with fluoroscopic guidance. Stimulation is performed at 2 Hz and up to 2.5 V (typical for motor stimulation) prior to injection of local anesthetic and lesioning. The posterior approach at T2 and/or T3 will most likely avoid these two nerve


RF lesion At the lumbar level

the needles can be placed at the inferior third of L2, superior or middle third of L3, or middle
third of L4. Multiple needles should be placed to obtain the
best neurolysis.


For pulsed lesions

the needle tip is slightly withdrawn because the target should be in front of the needle, as opposed to parallel to the needle for thermal lesions. Sensory stimulation is performed (50 Hz) to determine the lowest
threshold of stimulation and motor stimulation is also carried
out before doing the doing a thermal lesion (2–5 Hz
up to 3 V).


Pulsed lesions are carried out at

42° C, pulsed
mode, 2 3 20 ms/sec, 40 to 45 V for 120 sec. Thermal
lesions require local anesthetic prior to lesioning (2 ml of
2% lidocaine or equivalent), and the tip temperature is
brought to 80° C for 60 to 90 sec.


Stellate ganglion blockade and neurolysis

l Bleeding/hematoma
l Pneumothorax, hemothorax
l Vertebral artery injury or inadvertent injection
l Inadvertent injection into neuraxis
l Esophageal trauma
l Tracheal trauma
l Phrenic nerve injury
l Brachial plexus injury
l Recurrent laryngeal nerve injury
l Neuritis—any nerve or plexus listed above
l Postsympathectomy syndrome


Lumbar sympathetic blockade and neurolysis:

l Bleeding
l Infection
l Intravascular injection
l Intralymphatic injection
l Subarachnoid injection
l Discitis (transdiscal approach)
l Back pain
l Spinal nerve injury
l Genitofemoral nerve injury (L4 and L5 levels and too
posterior and lateral placement)
l Lumbar plexus injury
l Neuritis
l Horner’s syndrome and brachial paresis


Successful stellate ganglion block denervates

the upper cervical segments to produce Horner’s syndrome, which includes ptosis, miosis, and anhidrosis. Other signs include unilateral nasal stuffiness (Guttman’s sign) and warmth of the face.


The presence of Horner’s syndrome signifies

cephalic sympathetic blockade and does not imply sympathetic
denervation of the arm. If the block is used to treat the shoulder or upper limb, additional signs are needed to
determine sympathetic blockade in the area.


Complete block is reliably detected when a test of

adrenergic fiber activity (thermography, plethysmography, laser Doppler
flowmetry) is combined with a test of sympathetic cholinergic
(sudomotor) fiber activity (sweat test, sympathogalvanic


Increase in skin temperature is the most commonly used
clinical sign of

sympathetic blockade


The magnitude of temperature increases after complete sympathetic blockade depends on

the baseline values; greater increases are noted in patients with lower preblock temperatures. With
vasodilatation, the skin temperature will approximate core body temperature


Laser Doppler flowmetry

a sensitive method to evaluate
skin blood flow and to detect the presence of sympathetic


Blood flow can be determined accurately by using

plethysmographic methods such as venousocclusion
plethysmography. After successful sympathetic
block of the extremity, there is a marked increase of the
upward slope because of a significant increase in the pulse


standard tests of complete
sympathetic blockade

Abolition of sweating and of the sympathogalvanic. The sweat tests are more reliable than the SGR in predicting complete sympathetic blockade.response (SGR)


The sweat tests are performed in the following

The patient’s fingers or toes are wiped dry and the
cobalt blue– or ninhydrin–impregnated filter paper is
taped on them. A transparent tape is used so the change in
color of the cobalt blue paper secondary to sweating can be
seen. Sweating is signified by a change in color of the cobalt
blue filter paper from blue to pink and the appearance
of purple dots in the ninhydrin filter paper.


sympathogalvanic response
(SGR) can be recorded using a regular ECG machine

The right and left arm leads of the ECG are placed on the dorsum and palm of the hand (or dorsum and sole
of the foot) while the other leads are placed on the contralateral extremity, and the lead selector switch turned to
lead I. The stimulus can be a deep breath, pinprick, or loud
noise. The response consists of an upward or downward
deflection of the ECG tracing; either monophasic or biphasic.
Partial sympathetic block reduces the response
while complete block abolishes it, that is, the tracing is a straight line.


sympathogalvanic response
(SGR) shortcomings including

marked variations in the responses of patients to the different stimuli and difficulty in obtaining a satisfactory recording under clinical conditions


Relief of pain does not imply

complete sympathetic
blockade since patients with chronic pain may exhibit complete pain relief after partial sympathetic blockade.


Partial pain relief, on the other hand, signifies one of
two things:

the patient’s pain may be due to causes other than sympathetic-mediated pain (e.g., combined somatic
sensory- and sympathetic-mediated pain or combined
sympathetic-mediated and central pain) or the sympathetic blockade may be partial

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