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ULTRASOUND ARTICLE
Development and Validation of a New Technique for
Ultrasound-Guided Stellate Ganglion Block
Michael Gofeld, MD,* Anuj Bhatia, MD,Þ Sherif Abbas, MD,þ Sugantha Ganapathy, MD,§
and Marjorie Johnson, PhD||
Background and Objectives: Although the stellate ganglion is
located anteriorly to the first rib, anesthetic block is routinely performed
at the C6 level. Ultrasonography allegedly improves accuracy of needle
placement and spread of injectate. The technique is relatively new, and
the optimal approach has not been determined. Moreover, the location of
the cervical sympathetic trunk relative to the prevertebral fascia is
debatable.
Methods: Three-dimensional sonography was performed on 10 healthy
volunteers, and image reconstruction was completed. On the basis of
analysis of pertinent anatomy, a lateral trajectory for needle placement
was simulated. Accuracy was tested by injection of methylene blue in
cadavers. A clinical validation study was then conducted. A block needle
was inserted according to the predetermined lateral path, and 5 mL of
a mixture of bupivacaine and iohexol was injected. Spread of the contrast
agent was verified fluoroscopically.
Results: Image reconstruction revealed that the cervical sympathetic
trunk is located posterolaterally to the prevertebral fascia on the surface
of the longus colli muscle. The mean anteroposterior width of the muscle
at the C6 level was 11 mm. The lateral approach does not interfere with
any visceral or nerve structures. Anatomic dissection in cadavers
confirmed entirely subfascial spread of the dye and staining of the
sympathetic trunk. The contrast agent spread was seen in all patients
between the C4 and T1 levels in a typical prevertebral pattern.
Conclusions: This study revealed that, at the C6 level, the cervical
sympathetic trunk lies entirely subfascially. Subfascial injection via
the lateral approach ensures reliable spread of a solution to the stellate
ganglion.
(Reg Anesth Pain Med 2009;34: 475Y479)
S
tellate ganglion block has been used since the mid-1930s.
First implemented by Leriche and further refined by Findley
and Patzer, this method has been practiced since then without
significant modifications.1 It is a common intervention in the
diagnosis and management of sympathetically mediated pain
and vascular insufficiency of the upper extremities. In addition,
From the *Department of Anesthesia and Pain Medicine, University of
Washington, Seattle, WA; †University of Toronto, Sunnybrook Health
Sciences Centre; ‡GE Healthcare Canada, Mississauga; §University of
Western Ontario, London Health Sciences Centre; and ||Department of
Anatomy and Cell Biology, University of Western Ontario, London, Ontario,
Canada.
Accepted for publication March 13, 2009.
Address correspondence to: Michael Gofeld, MD, University of Washington,
Department of Anesthesia and Pain Medicine, 1959 NE Pacific St,
Room EE122F, Box 356044, Seattle, WA 98195 (e-mail: gofeld@
u.washington.edu).
This study was presented as a Best of Meeting Abstract at the Fall ASRA
Meeting, November 20, 2008.
Copyright * 2009 by American Society of Regional Anesthesia and Pain
Medicine
ISSN: 1098-7339
DOI: 10.1097/AAP.0b013e3181b494de
Regional Anesthesia and Pain Medicine
&
this type of anesthetic block has been advocated for treatment
of a variety of medical conditions, such as phantom pain, postherpetic neuralgia, cancer pain, cardiac arrhythmias, orofacial
pain, and vascular headache.2
Although an inferior C7 approach to stellate ganglion block
has been described,3 the anesthetic is routinely administered
according to the following anatomic landmarks: prominent
anterior tubercle of C6 vertebra (Chassaignac tubercle), cricoid
cartilage, and carotid artery.4 This essentially Bblind[ injection is
associated with a variety of adverse effects and complications,
such as intravascular injection, formation of hematomas, temporary paralysis of the recurrent laryngeal nerve, and esophageal
injury.2,6Y9
Injection of anesthetic at the C6 level has a long history, but
its reliability in achieving blockade of the sympathetic trunk and
cervicothoracic (stellate) ganglion remains uncertain. In addition, the course of the cervical sympathetic trunk (CST) relative
to the longus colli muscle and the prevertebral fascia continues
to be in dispute. Although some anatomic and imaging studies
indicate a subfascial position,5,10,11 others relate the path of the
trunk to the suprafascial plane.12,13
A method of stellate ganglion blockade under ultrasound
guidance was described8 in 1995 but has only recently gained
popularity. Ultrasound guidance can reduce the volume of local
anesthetic required to achieve reliable blockade and should
also prevent unintentional puncture of blood vessels and the
esophagus.8,9
The current study was undertaken to determine the
sonoanatomy of the CST and to determine the feasibility of
ultrasound-guided blockade. In addition, an attempt was made to
develop a safe and reliable injection technique, which will be
essential for clinical implementation and popularization. Finally,
the ultrasound-guided injection method was validated against
a standard imaging technique (fluoroscopy).
METHODS
Identification of Pertinent Anatomic Structures
and Simulation of Injection
Sunnybrook Health Sciences Centre research ethics board
waived their requirement for full application and approval of the
volunteer part of the protocol. We performed bilateral ultrasonographic examination of the anterolateral neck (left and right
sides) in 10 healthy volunteers, for a total of 20 examinations.
We used a Voluson-i machine and RSP6-16-RS transducer
(GE Medical Systems, Milwaukee, Wis). The transducer was
initially placed at the level of the cricoid cartilage, above the
sternocleidomastoid muscle. Short-axis ultrasonography revealed typical appearance of the C6 transverse process, with a
prominent anterior tubercle, a shorter posterior tubercle, and the
exiting C6 nerve root. The longus colli muscle was seen as an
oval structure adjacent to the base of the transverse process
and vertebral body. Sometimes the caudal portion of the longus capitis muscle could be seen as well (Fig. 1A). Scanning
Volume 34, Number 5, September-October 2009
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Gofeld et al
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Volume 34, Number 5, September-October 2009
FIGURE 1. Short-axis ultrasonography of the neck. A, C6 level. at indicates anterior tubercle; CA, carotid artery; IJV, internal jugular
vein; LCo, longus colli muscle; LCp, longus capitis muscle; N, C6 nerve root; pt, posterior tubercle; PVF, prevertebral fascia; SCM,
sternocleidomastoid muscle; B, C7 level. N indicates C7 nerve root; TP, transverse process.
caudally and slightly dorsally brought the C7 transverse process into the view. Unlike the C6 transverse process, the C7
transverse process has no anterior tubercle. The C7 nerve root
was situated just anterior to the transverse process (Fig. 1B).
At the C6 level, a spindle-shaped structure was inconsistently localized on the short-axis view (the middle cervical
ganglion). It was typically situated on the posterolateral surface
of the longus colli muscle; if the ganglion could not be identified,
some widening of the tissue plane below the prevertebral fascia
could usually be appreciated. Once all of the mandatory anatomic structures (transverse process of C6, vertebral body, and
longus colli muscle) had been visualized, 3-dimensional scanning was performed. After image reconstruction, the anatomic
location of the sympathetic trunk was identified and its relationship to neighboring structures was studied.
After analyzing the images, a previously described
ultrasound-guided anterior technique8 was deemed suboptimal.
Although displacement of the carotid artery and thyroid may
create a passage for needle placement (Fig. 2), this approach
requires application of force to the tissues and yet does not
prevent vascular and visceral damage. Therefore, an attempt to
develop a safer technique was deemed necessary. To accomplish
this, a simulated injection was performed in all volunteers. With
the transducer placed as shown in Figure 3, only the anterior
tubercle of the C6 transverse process was visible adjacent to the
projected entry point of the needle, and no visceral or neural
elements were situated on the line connecting the entry site and
the lateral surface of the longus colli muscle. Occasionally, the
internal jugular vein was seen within the projected needle track,
but it could be collapsed readily under light transducer pressure.
Typically, the simulated passage was entirely intramuscular,
that is, through the sternocleidomastoid muscle or the anterior
scalene muscle or both.
the prevertebral fascia on the surface of the longus colli muscle.
Methylene blue (0.2 mL) was injected, and the needle was
withdrawn.
The heads were turned slightly to the right, and necks were
positioned in extension. Dissections were performed anteriorly
to the sternocleidomastoid muscle approximately 2 spinal segments above and below the injection level (C6). The sternocleidomastoid muscle was retracted together with carotid sheath.
The deep fascia was exposed and dissected. The CST was identified and verified by an experienced anatomist (M.J.).
Imaging and Clinical Validation
The clinical phase of the study was approved by the
Sunnybrook Health Sciences Centre Research Ethics Board, and
the patients gave their written informed consent. We performed
10 sympathetic blocks in 7 patients at the level of the C6 vertebra, according to the knowledge of anatomy acquired through
examination of volunteers and dissection of cadavers (described
previously). Patients were placed in the lateral decubitus position, with the side to be treated uppermost. The skin was prepared and draped in a sterile fashion. The 13Y6 MHz 38-mm
broadband linear array (model HFL38; SonoSite, Inc, Bothel,
Wash) was covered by a sterile adhesive bandage (Tegaderm,
3M Health Care, St. Paul, Minn). Ultrasonography was performed as previously described. A skin wheal was raised with
1 mL of 2% lidocaine applied immediately posterior to the
ultrasound transducer. Under real-time ultrasound guidance, a
22-gauge spinal needle was inserted via the lateral pathway
Verification of Subfascial Location of the
Sympathetic Trunk (Cadaveric Study)
Dissection of a cadaver and publication of the images were
approved by the Cadaveric Research Review Committee of the
Department of Anatomy and Cell Biology, according to the
ethical standards of the University of Western Ontario.
Two adult cadavers (1 male and 1 female) were used. The
procedure was performed on the left side. The anatomic features
of the C6 vertebra and the longus colli muscle were studied in
the same fashion as in the healthy volunteers, but 3-dimensional
imaging was not performed. The injections were administered
via the lateral pathway determined in the initial phase of the
study. The block needle was advanced using in-plane short-axis
to the C6 vertebra technique and positioned immediately under
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FIGURE 2. Anterior short-axis view of the neck structures at the
C6 level, with application of pressure. The thyroid gland (Th)
and the carotid artery (CA) are clearly separated, and the
inferior thyroid artery (ITA) can be seen. VB indicates C6
vertebral body.
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Volume 34, Number 5, September-October 2009 Ultrasound-Guided Cervical Sympathetic Block
fluoroscopy was performed. Images of the cervical spine with
shadows of the contrast agent were printed for documentation.
All patients were closely monitored for at least 30 minutes
after the injection. Signs of the sympathetic blockade as well
as occurrence of adverse effects were recorded.
RESULTS
Identification of Pertinent Anatomic Structures
and Simulation of Injection
FIGURE 3. When the linear transducer is held in the optimal
position, only the anterior tubercle of C6 is seen posteriorly.
Simulated pathway (white line) connects the entry site and the
lateral surface of the longus colli muscle.
using the in-plane technique. Two syringes were connected to
the needle by means of a 3-way stopcock and extension tubing.
The 5-mL syringe was filled with 0.9% NaCl, and the 10-mL
syringe was filled with a mixture of 2.5 mL of 0.5% bupivacaine
and 2.5 mL of iohexol 240 mg I/mL. Once placement of the
needle had been confirmed, 1 to 2 mL of NaCl was injected to
confirm subfascial placement of the needle. The NaCl allowed
clear separation of the tissue planes (Fig. 4). If the spread was
appropriate, 5 mL of the bupivacaine-iohexol mixture was
injected, and the needle was withdrawn. However, if the NaCl
solution was observed above the fascia or within the muscle, the
needle was gently repositioned before injection of the
bupivacaine-iohexol mixture. Immediately after the injection,
the patient was positioned supine, and anteroposterior and lateral
FIGURE 4. Block needle (arrowheads) has been placed under the
prevertebral fascia. Initial injection of 0.9% NaCl (asterisks)
separates LCo from the fascia.
* 2009 American Society of Regional Anesthesia and Pain Medicine
The images obtained from healthy volunteers were
analyzed by comparing the axial image with sagittal and coronal
views; this was accomplished by digitally Bslicing[ the tissue
planes starting just above the prevertebral fascia. In this way, we
were able to identify the fascial planes, the sympathetic trunk,
and the longus colli muscle. Image analysis showed that the
CST is typically situated subfascially between the posterolateral
surface of the longus colli muscle and the prevertebral fascia,
posterior to the common carotid artery. Coronal imaging showed
the oblique descending pathway of the CST from the C5 level to
the C7 level (Fig. 5). The epimysium of the longus colli muscle
appears as a soft hyperechoic nonsolid layer of connective tissue.
The mean anteroposterior thickness of the muscle on C6 level
was 11 mm (range, 9.1 T 1.27 mm), and there were no significant
differences between the left and right sides. In 3 volunteers, a
distinct nodular structure was apparent, which we identified as
the middle sympathetic cervical ganglion. Using the caliper tool,
a line was extended from the skin (needle entry site) to the
sympathetic trunk (lateral pathway for placement of the block
needle). It consistently traversed the sternocleidomastoid and/or
the anterior scalene muscle, without interfering with any visceral
or nerve structures.
Verification of Subfascial Location of the
Sympathetic Trunk (Cadaveric Study)
Deposition of methylene blue was carefully observed
during dissection of the cadavers. No dye was found superficial
to the prevertebral fascia (Fig. 6), and the sympathetic trunk was
strongly stained at the level of injection (C6 vertebra). Even with
FIGURE 5. Reconstruction of 3-dimensional image at C6. On
the axial image navigating ‘‘dot’’ is positioned under the
prevertebral fascia (upper left); coronal view (lower left) showed
the cervical sympathetic trunk spread-eagled on the longus colli
muscle. No solid fascial layer is seen between the trunk and the
muscle.
477
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Regional Anesthesia and Pain Medicine
Gofeld et al
FIGURE 6. Dissection of female cadaver after injection of
methylene blue. The sympathetic trunk (on ligature) is strongly
stained at the level of injection. CD indicates caudad; CP,
cephalad; LAT, lateral; MES, mesiad; PVF, prevertebral fascia
(removed).
a low-volume injection (0.2 mL), the CST in the target area was
completely bathed in dye.
Imaging and Clinical Validation
The injectate spread between the C4 and T1 spinal
vertebrae in all cases, with occasional extension to the C3 (n =
2) and the T2 levels (n = 1). The radiographic results were
compatible with previous descriptions4 of the typical prevertebral radiopaque contrast agent deposit (Fig. 7). No intramuscular deposit pattern of the contrast was observed in all cases.
All of the patients had 2 or more clinical signs of successful
sympathetic blockade of the upper extremity, such as temperature elevation, venous engorgement, and vascular flushing.
Some degree of Horner syndrome was evident in all patients.
Despite the subjective feeling of a lump in the throat (reported
by 2 patients), no cases of hoarseness were observed, and there
were no other complications or adverse effects.
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Volume 34, Number 5, September-October 2009
first rib. Cephalad to it, at the level of C6, the middle cervical
ganglion may be located anterolaterally to the belly of the longus colli muscle, or alternatively, only traversing fibers of the
CST are apparent.5,17 The cervical prevertebral fascia is attached
to the base of the skull and extends over the prevertebral muscles (longus capitis, rectus capitis, and longus colli muscles) to
attach distally at the T4 vertebra, just beyond the longus colli
muscle. This position of the fascia forms a plane along which the
injected fluid can flow.
Given that only traversing sympathetic fibers or middle
cervical ganglia can be found at the C6 level,5 the procedure
should more accurately be called cervical sympathetic block.
Several clinical and cadaver trials have been performed in an
attempt to elucidate the pattern of spread when solutions are
injected at the C6 level.10,16,18Y20 The results of these studies
have been conflicting. The results of a cadaver study suggested
that only deposition of solution into the prevertebral interlaminal
space provides reliable spread to the stellate ganglion.20
Having no agreement regarding radiologically controlled
injections, routine blind technique is deemed even more ambiguous. It is typically performed using so-called paratracheal
approach and placing the needle toward the lateral part of the C6
vertebral body. The needle is then to be withdrawn by 1 to 5 mm
and a solution is to be injected. This maneuver was claimed to be
sufficient to position the needle outside the longus colli muscle
(ie, where the sympathetic trunk is believed to be situated).
However, our results indicate that the actual size of the longus
colli muscle is thicker than was previously suggested. As such,
routine injection by the traditional method may lead to intramuscular injection, and the CST will be anesthetized only by
overflow or diffusion of the injectate.
Fluoroscopy-guided cervical sympathetic block has the
advantages of allowing identification of the bony anatomy and
reducing overall risk through prior injection of a contrast agent.
However, the anatomic position of the CST is determined by
surrounding soft tissues (the longus colli muscle, the thyroid,
DISCUSSION
The aim of this study was to conduct in vivo verification
of assumption that the CST is located subfascially in the prevertebral compartment and precise injection of relatively small
(5 mL) volume will spread from the midcervical CST to the
T1 level where the cervicothoracic (stellate) ganglion is located.
Both research targets were accomplished. Three-dimensional
ultrasonography provided the evidence of in vivo topographic
anatomy, whereby cadaver dissection and clinical imaging delivered the answer regarding feasibility and accuracy of the
injection technique. We had no intention to support or decline
clinical efficacy of the stellate ganglion anesthetic blockade.
The anatomy and position of the stellate ganglion (also
known as the cervicothoracic ganglion) have been confirmed
by dissection, magnetic resonance imaging, and computed
tomography.5,14Y16 This ganglion is described as a structure 1 to
2.5 cm long, approximately 1 cm wide, and 0.5 cm thick. It is
present in approximately 80% of the population, representing a
fusion of the inferior cervical ganglion and the first thoracic
ganglion.15 It is located just anterior to the transverse process
of the C7 vertebra and superior or anterior to the neck of the
478
FIGURE 7. Anteroposterior radiograph of the contrast spread.
The dye is clearly seen at the level of T1 where the stellate
ganglion is typically located.
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Regional Anesthesia and Pain Medicine
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Volume 34, Number 5, September-October 2009 Ultrasound-Guided Cervical Sympathetic Block
and the esophagus) rather than the cervical vertebrae. As such,
fluoroscopic control cannot be used to ensure precise needle
placement, and injection of a contrast agent is required; however,
the contrast agent may show aberrant and inconsistent spread.
Therefore, the success or failure of either blind or fluoroscopyguided injection depends entirely on the thickness of the longus
colli muscle and the anatomic location of the CST.
Ultrasound guidance was deemed the logical solution to
ensure accurate injection when soft tissues are involved. Clear
imaging of the muscles, fasciae, blood vessels, viscera, and bone
surface makes ultrasonography superior to fluoroscopy for
image-guided CST block. In 1995, Kapral et al8 described a
technique and published a case series. Compared with blind
injection, these authors found that ultrasound-guided stellate
ganglion block used a lower volume of local anesthetic (5 mL
rather than 8 mL), was not associated with formation of hematomas (whereas 3 patients in the blind injection group had a
hematoma), and was associated with more rapid onset of Horner
syndrome. However, because tissue visualization was probably
not feasible below the C7 level, these authors concluded that
a local anesthetic depot was limited to the C4 to C7 levels and
speculated that the upper extremity sympathetic blockade was
not related to blockade of the stellate ganglion per se. Their
findings agreed with those published by Hogan and Erickson,15
but these observations and conclusions have been challenged
by results presented here, in which the contrast agent spread
between the C4 and T1 levels in all 10 cases, occasionally
reaching T2 level.
Shibata et al11 suggested that subfascial injection would
result in better spread of the injectate and more reliable sympathetic blockade. The published image is ambiguous, and it is
not clear whether subfascial or intramuscular injection was
actually performed. Such deposition of the injectate can be a
limiting factor in the onset and spread of blockade. In the present
study, injection of 5 mL of local anesthetic subfascially but externally to the longus colli muscle ensured reliable spread of the
solution to the stellate ganglion.
Narouze et al9 further emphasized the risks of a blind approach, pointing out that blind injection at the C6 level on
the left side may cause unintentional esophageal puncture; in
addition, the needle invariably traverses the thyroid gland.
Hematoma formation is likely related to damage to the inferior
thyroid artery. These observations are important, but to date, no
practical solution to the problem has been recommended. Using
the anterior approach, the needle is inserted through the thyroid
gland, adjacent to the carotid artery and close to the inferior
thyroid artery and the recurrent laryngeal nerve. In addition, this
approach requires the application of pressure to the anterior
neck, which is troubling for most patients.
In the study reported here, we attempted to find a pathway
for needle placement, away from vital neck structures. This
method has been previously published but required experimental
validation.21 We performed scanning and simulated injection
using volunteers, confirmed these initial results in 2 cadavers
and in a small clinical study. Three-dimensional reconstruction
and image analysis supported our conclusion that the CST is
located below the prevertebral fascia, on the surface of the longus colli muscle. The longus colli muscle is thicker than can be
inferred from the literature. Therefore, we conclude that routine
blind injection may result in intramuscular deposition of the
injectate. Visualization of the soft tissue, vessels, and cervical
sympathetic ganglia may make ultrasound imaging guidance
superior to fluoroscopy. Subfascial injection of 5 mL of local
anesthetic reliably spread to the midneck CST and the stellate
ganglion. Ultrasound guidance may prevent complications and
* 2009 American Society of Regional Anesthesia and Pain Medicine
adverse outcomes associated with either blind or fluoroscopyguided techniques, but a larger clinical study will be required
to prove this assertion.
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