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420 Theresa Tak Lai LI
patient undergoing regional blockade and advanced
interventional pain management procedures. e
following issues are essential for smooth running of
the regional technique:
Equipment
Appropriate and adequate sterile equipment
for block procedures are made available prior
to commencement of the procedure. Routine
maintenance and checking should be performed at
regular intervals.
Fluoroscopy
Radiological localising is essential for all cases and
in particular when difficulty is anticipated due to
poor landmarks or anatomical anomalies and when
neurolytic procedures are planned.
Monitoring
Vital signs recording are mandatory for all procedure
especially in cases where monitored anaesthetic care
is administered.
Personnel
e pain management team comprises the
responsible physician, pain nurse and theatre
staff familiar with the technique and potential
complications of the procedure.
Informed consent
e physician should obtain informed consent
from the patient in regard to the purpose and
technique of the procedure, the expected outcome,
the potential side effects and the associated risks.
Guidelines and protocols
A set of guidelines and protocols for various
procedures should be kept in the procedure theatre
for references and should be updated and reviewed
in time.
Brachial Plexus Block
Brachial plexus block was first performed by two
surgeons: Halsted in 1884 and Crile in 1887,
with direct exposure in the neck to accomplish the
block [26]. In 1911, Hirschel described the first
percutaneous brachial plexus block and since then
the efficacy of the procedure has been confirmed
and widely used in the field of clinical anaesthesia
and pain management [26]. e technique of
brachial plexus block is further refined with
advanced medical technology by the use of nerve
stimulation and sonographic guidance. e four
usual sites of approach for brachial plexus blocks
are the interscalene space, the supraclavicular area,
and the infraclavicular and axillary regions.
Anatomy
e brachial plexus is formed by the anterior
rami of C5, C6, C7, C8 and T1, with minor
contributions from C4 and T2. ese nerve roots
exit the lateral aspect of the cervical spine to form
the plexus and the nerves then pass downward
and laterally. Together with the subclavian artery,
they run between the anterior and middle scalene
muscles passing behind the clavicle and above the
top of the first rib to reach into the axilla where
they further divide into various terminal branches.
e subdivisions can be summarised as below (Fig.
26.01):
1. Roots. ey lie in the interscalene groove
between the anterior and middle scalene
muscles covered by the prevertebral fascia.
2. Trunks. e C5 and C6 roots form the upper
trunk, the C7 continues as the middle trunk,
and the C8 and T1 roots form the lower
trunk. ese trunks lie in the same plane as the
subclavian artery, with the upper and middle
trunks above and the lower trunk posterior to
the subclavian artery, in close proximity to the
first rib.
3. Divisions. Each trunk divides into anterior
and posterior divisions.
4. Cords. e posterior cord is formed by the
union of the posterior divisions of all the
trunks. e lateral cord is formed by the
anterior divisions of the upper and middle
trunks. e medial cord is formed by the
anterior division of the lower trunk. e
posterior, lateral and medial cords are so
named due to their relationship with the
axillary artery as they lie behind the pectoralis
minor muscle.
5. Branches. Peripheral nerves can branch off
from the roots, trunks and cords. More
commonly encountered in clinical practice
are the terminal branches arising from the
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Peripheral Nerve Blocks 421
cords. e lateral cord gives off the lateral
pectoral nerve, the musculocutaneous nerve
and the lateral head of the median nerve.
e medial cord gives off the medial pectoral
nerve, the medial cutaneous nerve of the arm
and forearm, the medial head of the median
nerve and the ulnar nerve. e posterior cord
gives off the upper and lower subscapular
nerves, the nerve to the latissimus dorsi, the
axillary nerve to the shoulder joint and the
radial nerve.
In terms of functional anatomy, motor and sensory
innervations of the upper extremity, except for the
skin over the upper part of the shoulder (C3, C4)
and upper part of the medial arm (T2), are derived
from the brachial plexus.
Indications
e interscalene and supraclavicular techniques
are the preferred methods for brachial plexus block
when anaesethesia or relaxation of the shoulder is
desired and are commonly used to facilitate surgical
operation around the shoulder and above the elbow
[26]. e infraclavicular approach is preferred for
operations in the forearm and around the elbow.
e axillary approach is preferred for operations on
the hand and the medial side of the elbow [26].
In acute pain management, brachial plexus block
with local anaesthetic agent is used to treat pain due
to acute herpes zoster, brachial plexus neuritis, and
trauma to the shoulder and upper limb [35]. It also
serves as a diagnostic tool for evaluation of shoulder
and upper extremity pain, and especially in chronic
pain conditions such as complex regional pain
syndrome [35]. Occasionally, destruction of the
brachial plexus may be considered for management
of intractable cancer pain due to invasive tumours
of the brachial plexus, and tumours of the soft
tissue and bone of the shoulder and upper limb.
However, a prognostic local anaesthetic block has
to be performed prior to neurolysis to assess the
degree of motor loss likely to be experienced by the
patient.
Procedure
e brachial plexus can be targeted in four
different approaches: interscalene, supraclavicular,
infraclavicular and axillary, adopting different
techniques to access the brachial plexus in different
regions (Fig. 26.02). Use of a nerve stimulator
technique is widely practised in anaesthesia and
pain management because it allows fine tuning
of needle positioning for optimal placement. e
use of nerve stimulation further obviates the need
for patient co-operation, thereby allowing use
of sedation titrated to individual need and thus
enhanced patient satisfaction [5].
Interscalene approach
e patient is placed in a supine position with the
head turned away from the side to be blocked. e
patient is asked to touch the ipsilateral knee to
Figure 26.01 Drawing of the anatomy of the
brachial plexus.
Figure 26.02 Drawing of the brachial plexus with
various approaches shown
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422 Theresa Tak Lai LI
depress the shoulder and lift the head to enhance
palpation of the lateral border of the clavicular head
of the sternomastoid muscle. e cricoid cartilage
(C6) is identified and at this level a groove is palpated
between the posterior border of the sternomastoid
muscle and the anterior scalene muscle. e skin
overlying this area is then prepared with antiseptic
solution.
e block or nerve stimulating needle is inserted
at this point perpendicular to the skin in all planes
with a slightly caudal and inferior trajectory. e
needle is advanced to a depth of around 2 cm
such that the needle tip impinges on the brachial
plexus as it traverses the interscalene space.
When contractions of the muscles at or below
the shoulder — either deltoid or biceps twitches
— are observed with an initial current of 1.5 mA
at 2 V and maintained when the current is reduced
to 0.5 mA at 2 V, the needle can be considered to
be in the correct place. Once needle position with
negative aspiration for blood and cerebrospinal
fluid is confirmed, 30 ml of local anaesthetic
agent is incrementally injected and the patient
closely monitored for signs of systemic toxicity or
inadvertent subarachnoid injection.
Supraclavicular approach
e patient is placed in a supine position with a
roll between the scapulae. e head is turned away
from the side to be blocked. e patient may be
asked to lift the head to outline the sternomastoid
and scalene muscles. e correct point of needle
entry is on the lateral border of the anterior scalene
muscle at the midpoint of the clavicle, which is
located midway between the acromial end and the
sternal end of the clavicle. After sterile preparation
of the region, the needle is inserted in a backward-
inward-downward manner and perpendicular to
all planes at this level in the neck. It should be
directed to but not necessarily touching the first
rib.
Stimulation of the forearm, wrist or digits is elicited
at a usual depth of 2 cm. If hand or finger movements
are not produced at a depth of more than 2.5 cm,
the needle should be withdrawn and re-advanced
with a slightly more cephalad trajectory. However,
if the first rib is encountered before paraesthesia is
elicited, the needle should be walked laterally and
slightly posteriorly. Confirmation of the nerves can
also be achieved by electrical stimulation with a
current of 0.5 mA at 2 V and endpoints observed
are muscle twitches in biceps, triceps and preferably
hand muscles for surgery distal to the elbow. After
negative aspiration for blood and cerebrospinal
fluid, 20 ml of solution is injected and the patient
closely monitored for signs of systemic toxicity or
inadvertent neuraxial injection.
Infraclavicular approach
ere are various ways of conducting the
infraclavicular approach to brachial plexus block.
e following method uses the nerve stimulation
technique. e patient is placed supine with the
arm to be blocked abducted to 90° and the head
turned away. After the patient’s skin is sterilised,
the ground electrode should be attached to the
opposite shoulder. e point of needle entry is 2.5
cm below the midpoint of the clavicle. e nerve
stimulator needle is introduced through the skin
and directed laterally towards the brachial artery
and advanced at a 45° angle to the skin.
Initial stimulation causes the pectoralis group of
muscles to contract and adduct the shoulder and
will stop as the needle tip is past the muscles. As
the needle approaches the fibres of the brachial
plexus, muscles supplied by the musculocutaneous,
median, ulnar and radial nerves will contract with
each impulse. Clinically, flexion or extension of the
elbow (musculocutaneous nerve), palmar flexions
of the wrist and flexion of all digits (median nerve),
ulnar deviation of the wrist (ulnar nerve) and
wrist extension (radial nerve) are observed with
stimulation of the respective nerves. When muscle
movements are still present at a lowest current level
(0.5 mA at 2 V) the needle is in close proximity to
the brachial plexus and 30 ml of local anaesthetic
agent is incrementally injected.
Axillary approach
e axillary block aims to block the terminal
branches of the brachial plexus which includes
the radial, ulnar and median nerves. e patient is
placed in a supine position with the arm abducted
90° at the shoulder joint and elbow. Under sterile
conditions, the axillary artery is palpated with one
finger and the palpating hand rested on the patient’s
arm. e block needle is inserted just proximal to
the palpating finger.
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Peripheral Nerve Blocks 423
e needle’s position is confirmed by observing
movements of the muscles in the hand elicited at a
lowest current (less than 1 mA at 2 V) with a nerve
stimulator. When needle position is confirmed,
the axillary artery is compressed by digital pressure
prior to slow injection of anaesthetic solution. is
manoeuvre helps to facilitate the proximal spread
of injectate to block the musculocutaneous nerve,
which leaves the lateral cord high in the axilla.
Complications
e proximity of the brachial plexus to the subclavian
and axillary arteries and other larger vessels along
the course poses potential risk for inadvertent
intravascular injection or local anaesthetic toxicity
from intravascular absorption. is is particular
true for the interscalene approach when a large
dose of local anaesthetic agent is required; careful
attention should be paid when calculating the total
milligram dose of drug that may safely be given. e
vascularity also increases the incidence of postblock
ecchymosis and haematoma formation. Application
of firm pressure and cold packs may reduce the
incidence [37]. In addition, the proximity of the
brachial plexus to the neuraxial structures and the
phrenic nerve can also give rise to complications.
Total spinal anaesthesia due to inadvertent
intrathecal injection either directly or via extension
into a dural cuff has been reported [11]. It should
be anticipated that the phrenic nerve will also be
blocked with the interscalene and supraclavicular
approaches. However, in the absence of significant
pulmonary disease, unilateral phrenic nerve block
should rarely give rise to disturbance in respiratory
function. Owing to the close proximity of the apex
of the lung, pneumothorax is a possibility with the
supraclavicular technique but less likely with other
approaches. Horner’s syndrome is a side effect of
brachial plexus block rather than a complication.
e sympathetic innervation of the upper extremity
is derived from the T1 to T5 spinal segments and
the T1 and T2 postganglionic fibres traversing the
brachial plexus are often blocked together with the
plexus.
New advancements
e use of ultrasound for nerve block was first
reported by La Grange and colleagues in 1978,
when they performed supraclavicular brachial
plexus blocks with the help of a Doppler ultrasound
blood-flow detector [14]. e technology and
clinical understanding of anatomical sonography
have evolved greatly over the past decade. In some
centres, ultrasonography has become a routine
technique for regional anaesthetic nerve block.
Ultrasound guidance enables the operator to secure
an accurate needle position in terms of depth and
direction, and the ability to monitor the distribution
of the local anaesthetic in real time [13]. e risk of
local anaesthetic toxicity secondary to intravascular
injection is reduced with improved accuracy of
needle positioning. is poses additional advantages
over conventional guidance techniques such as
nerve stimulation to improve the success and
quality and thus the onset of anaesthesia/analgesia.
Furthermore, the exact location of nerves can be
identified to prevent intraneuronal injection and
this is particularly useful in patients with difficult
anatomical landmarks. e nearby vital structures
such as vasculature and pleura are also recognised
to avoid unintentional puncture.
Principle of medical ultrasound
imaging
e ultrasound machine transmits high-frequency
sound pulses in the frequency range of 5 to 12
MHz into the body using a hand held probe (Fig.
26.03). e probe of a higher range frequency
(10–12 MHz) is selected for superficial approaches
while the lower range frequency probe (5–7 MHz)
is used on deeper structures. e connective tissue
inside the nerves (perineurium and epineurium)
and tissue boundaries reflects ultrasound waves.
ese sound waves are reflected back towards
the probe with the greatest amount of reflection
achieved when the sound beam is directed nearest
to and at 90° to the target. e reflected waves
are received by the probe and relayed back to the
machine, which calculates the distance from the
probe to the organ using the speed of sound in
tissue and the time for each reflection. e machine
finally displays the distances and intensities of the
echoes on the screen, forming a two-dimensional
image [6].
Peripheral nerves may appear as hypoechoic (dark)
or hyperechoic (bright) sonographic structures,
depending on the size of the nerve, the sonographic
frequency and the angle of the ultrasound beam
[6]. With reference to the brachial plexus, the
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424 Theresa Tak Lai LI
nerves present as oval echographic structures with
hypoechoic predominance in the interscalene
and supraclavicular regions or hyperechoic
predominance in the infraclavicular region [3, 18].
e vasculature is also recognised as hypoechoic
structures and easily distinguished by the presence
of pulsations in arteries and the compressibility of
veins by the ultrasound probe.
Figure 26.03 Photo of an ultrasound machine (with
permission of Esaote China Ltd)
Figure 26.05 Interscalene approach with needle
advancement along the short axis of the ultrasound
probe
Figure 26.06 Transverse sonogram in the
interscalene region showing the brachial plexus
as hypoechoic nodules (N) between anterior
scalene muscle (ASM) and middle scalene muscle
(MSM), beneath the posterior margin of the
sternocleidomastoid muscle (SCM). CA = carotid
artery; IJV = internal jugular vein
Figure 26.04 Interscalene approach with needle
advancement along the short axis of the ultrasound
probe
Ultrasound-guided interscalene
approach
Position the patient supine with the head turned
to the opposite side. Perform antiseptic preparation
to the skin and the ultrasound probe. en place
a linear high-frequency (10–12 MHz) probe
firmly on the neck at the cricoid cartilage level to
obtain a cross-sectional view of the brachial plexus
(Figs. 26.04 and 26.05). ese figures show the
operator inserting the needle in the short axis of
the ultrasound probe.
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Peripheral Nerve Blocks 425
in the supraclavicular fossa in the coronal plane.
A cross-sectional view of the subclavian artery can
be seen, and the trunks or divisions of the brachial
plexus should appear as oval hypoechoic structures
lateral to the subclavian artery and on top of the
hyperechoic first rib (Fig. 26.08).
en insert a 22G x 50 mm insulated short-bevelled
block needle on the lateral end of the ultrasound
probe and advance along the long axis of the probe
and in the same plane as the ultrasound beam (Fig.
26.09). e needle creates a dorsal acoustic shadow
and is also identified by direct needle movement
and tissue displacement. e needle tip and shaft
can be visualised in real time as they approach the
target nerves. e confirmation of identity of the
nerves can be performed by electrical stimulation
as described earlier. Fill the needle system with
local anaesthetic agent before puncture to avoid air
inclusion. Once optimal needle position is achieved,
the calculated amount of local anaesthetic is injected
and the spread of solution observed in real time. A
favourable spread should appear as a hypoechoic
zone which gradually encircles the nerves. If the local
anaesthetic spread is inadequate and inappropriate,
the needle can be repositioned accordingly.
Ultrasound guided
infraclavicular approach
is approach is based in the anatomical
arrangement of the cords of the brachial plexus
Figure 26.07 Interscalene approach with needle
advancement along the long axis of the ultrasound
probe in a lateral to medial direction
Figure 26.08 Transverse sonogram in the
supraclavicular region shows brachial plexus as
a group of hypoechoic nodules (N) lateral to tha
subclavian artery (SA) and cephalad to the first rib
(FR). ASM = anterior scalene muscle; MSM = middle
scalene muscle; SV = subclavian vein; P = pleura
e following method describes the interscalene
approach with needle insertion in the long axis
of the ultrasound probe and the brachial plexus
blocked in a lateral to medial direction. e trunks
appear as an oval hypoechoic structure lying in the
interscalene groove between the anterior and middle
scalene muscles on ultrasonogram (Fig. 26.06). A
22G x 50 mm insulated short-bevelled block needle
is inserted on the lateral end of the ultrasound probe
and advanced along the longitudinal or long axis
view (Fig. 26.07). is approach allows the needle
shaft and tip to be visualised in real time as needle
advancement towards the target nerves. e needle
creates a dorsal acoustic shadow and is also identified
by direct needle movement and tissue displacement.
e confirmation of identity of the nerves can be
obtained by electrical stimulation as described in the
previous section. Once optimal needle position is
achieved, the calculated amount of local anaesthetic
agent is injected and the spread of solution observed
in real time. It is important to fill the needle system
with local anaesthetic agent before puncture to avoid
air inclusion. A favourable spread should appear as a
hypoechoic zone which gradually encircles the nerves
and opens up the interscalene groove. If the local
anaesthetic spreads in the inappropriate direction,
the needle can be repositioned accordingly.
Ultrasound guided
supraclavicular approach
Position the patient supine with the head turned
away from the side to be blocked. Perform antiseptic
preparation to the skin and the ultrasound probe. A
linear 10–12 MHz ultrasound probe is then placed
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426 Theresa Tak Lai LI
around the second part of the axillary artery. At the
infraclavicular level, the lateral cord lies superior
and lateral, the posterior cord lies posterior, and the
medial cord lies posteroinferior and medial to the
axillary artery[18, 19, 30]. e patient lies supine
for this procedure. After antiseptic skin preparation,
a linear 7 MHz probe is applied medially to the
coracoid process underneath the clavicle in a
parasagittal plane to obtain a cross-sectional view of
the brachial plexus (cords) and the axillary artery.
e first thoracic ventral branch contributes to the
formation of the lower trunk of the brachial plexus.
Only a small part continues as the first intercostal
nerve. e second intercostal nerve becomes the
lateral cutaneous branch and the intercostobrachial
nerve, innervating the medial side of the arm. Each
of the other intercostal nerves becomes a lateral
cutaneous branch innervating the skin of the
lateral body wall, and an anterior cutaneous branch
innervating the skin of the anterior body wall; skin
coverage up to the xiphisternum by the upper six
Figure 26.09 Supraclavicular approach with needle
advancement along the long axis of the ultrasound
probe in a lateral to medial direction
Figure 26.10 Transverse sonogram in the
infraclavicular region showing the brachial plexus as
hyperechoic nodules (L = lateral cord, M = medial
cord, P = posterior cord). AA = axillary artery; AV =
axillary vein; PMM = pectoralis major muscle; PMiM
= pectoralis minor muscle
Figure 26.11 Infraclavicular approach with needle
advancement along the long axis of the ultrasound
probe in a cephalad to caudad direction
e pectoral major and minor muscles are seen
overlying the pulsatile axillary artery and axillary
vein, which are both hypoechoic in appearance
(Fig. 26.10). e cords appear hyperechoic, with
the lateral cord superior to and the posterior cord
posterior to the artery.
A 22G x 50 mm insulated short-bevelled block
needle is passed in the plane of the ultrasound
beam below the clavicle along the long axis of the
ultrasound probe and in a cephalad to caudad
direction at a 45° angle to the skin (Fig. 26.11).
e confirmation of identity of the nerves can be
performed by electrical stimulation as described
earlier. Fill the needle system with local anaesthetic
agent before puncture to avoid air inclusion. Once
optimal needle position is achieved, the calculated
amount of local anaesthetic agent is injected and
the spread of solution observed in real time. is
should appear as a hypoechoic zone which gradually
encircles the nerves and is most favourably posterior
to the axillary artery next to the posterior cord. is
manoeuvre invariably will block both the posterior
and medial cords.
Superficial spread of solution in the pectoralis
muscles is often associated with failed block. If
feasible, the needle should be withdrawn and
redirected towards the anterosuperior position of
the axillary artery to achieve a spread of solution to
the lateral cord for complete blockade. If the local
anaesthetic spread is inadequate and inappropriate,
the needle can be repositioned accordingly.
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Peripheral Nerve Blocks 427
Figure 26.12 Axillary approach with needle
advancement along the long axis of the ultrasound
probe in a lateral to medial direction
Figure 26.13 Transverse sonogram with colour
Doppler in the axillary region showing three
terminal branches of the brachial plexus as
hypoechoic nodules with hyperechoic rims (M
= median nerve, U = ulnar nerve, R = radial
nerve). AA = axillary artery; AV = axillary vein;
MC = musculocutaneous nerve; B = biceps; CB =
coracobrachialis; T = triceps
Ultrasound guided axillary
approach
e patient is positioned supine with the arm of
the side to be blocked abducted at right angles
to the body. After antiseptic skin preparation,
a 10–12 MHz ultrasound probe is placed in the
transverse plane along the axillary crease high up
in the axilla. A 22G x 50 mm insulated short-
bevelled block needle is inserted at the lateral end
of the ultrasound probe and advanced along the
long axis of the probe and in the same plane as the
ultrasound beam (Fig. 26.12). A cross-sectional
view of the terminal branches of the brachial plexus
will appear as round or oval hyperechoic rimmed
nodules encircling the hypoechoic axillary artery
(Fig. 26.13). e identity of individual branches
can be confirmed by electrical stimulation as
described in the previous section. Once the needle
position is secured, divided doses of the calculated
amount of local anaesthetic agent are injected at
each nerve location and spread of solution observed
in real time.
A favourable spread should appear as a hypoechoic
zone which gradually encircles the nerves. As
mentioned in the description of the anatomy of
the brachial plexus, the musculocutaneous nerve
originates in the lateral cord high in the axilla.
Being located between the coracobrachialis and
biceps muscles, it is usually separated from the other
nerves at the level of the axilla and is commonly
missed by the conventional axillary approach. In
most patients, the musculocutaneous nerve can
be readily visualised and effectively blocked by
injecting another 3 ml of the local anaesthetic
after moving the needle and the ultrasound probe
slightly in a cranial direction.
Intercostal Nerve Block
Indications
Intercostal nerve block is administered after surgery
of the upper abdominal and thoracoabdominal
regions for postoperative pain relief. It is also
specific and effective for pain relief in fractured
ribs [21, 27]. e pain from the chest wall
contusion, pleurisy, flail chest and sternotomy or
fractured sternum can be successfully controlled
with this nerve block [21, 27]. Neurolytic block is
performed for pain secondary to bony metastasis
to ribs [37].
Anatomy
e spinal nerve in the paravertebral region divides
into a dorsal branch, innervating the muscle and
skin of the back, and a ventral branch which forms
intercostal nerves for the 11 intercostal spaces and
the subcostal nerve below the last rib.
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428 Theresa Tak Lai LI
branches and the anterior abdominal wall with T10
around the level of umbilicus by T7 to T11 nerves
(Fig. 26.14) [27].
e upper six intercostal nerves innervate the
intercostal muscles, and the lower five intercostal
nerves and the subcostal nerves innervate the
abdominal muscles as well as the intercostals
muscles. Each intercostal nerve runs in the
neurovascular plane along with an artery and a vein
in the costal groove at the inferior border of a rib.
is neurovascular plane is between the internal
intercostal muscle and the innermost muscle
layer consisting of subcostalis, sternocostalis and
innermost intercostal muscles (Fig.26.15). Solution
injected between the ribs can spread into adjacent
spaces and flow medially into the epidural space.
Procedure
e intercostal block can be performed at three
sites; the angle of the rib posteriorly; the posterior
axillary line and midaxillary line laterally; and
the anterior axillary line anteriorly. In the classic
approach, intercostal nerve block is performed
posteriorly at the angle of the ribs and just lateral
to the sacrospinalis muscle group (Fig. 26.16). At
this point the thickness of the rib is about 8 mm.
e patient usually lies in the prone position for
the procedure. After the usual skin preparation,
the needle entry is made over the rib selected for
the block either by manual palpation or more
precisely by direct radiological visualisation. e
needle should touch the lower half of the rib
subcutaneously. With one hand holding the needle
and syringe, the other hand moves the skin caudally
over the rib and thus the needle point “walks” off
the lower edge of the rib [34]. e needle is then
Figure 26.14 Drawing of the anatomy of an
intercostal nerve
Figure 26.15 Drawing of a needle inside the
intercostal space
Figure 26.16 Photo of a spinal needle at the angle
of the ninth rib
Figure 26.17 Radiograph illustrates the spread of
contrast along an intercostal nerve
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Peripheral Nerve Blocks 429
pushed about 3 mm deeper until a slight click is felt
as the tip enters the correct space. A small amount
of non-ionic contrast medium (Iopamiro 300) is
injected to outline the nerve sheath. After negative
aspiration for air or blood, either 2 ml 0.5%
bupivacaine is injected for diagnostic or prognostic
block, or 2 ml 10% phenol in Conray contrast
medium is injected for neurolytic block with a
direct view of injectate spread on fluoroscopy (Fig.
26.17).
Complications
Inadvertent needle puncture of the pleura can cause
a pneumothorax. Careful performance reduces the
risk of this complication. If, however, it occurs,
it can be easily managed by observation, with or
without simple aspiration; very occasionally is chest
drain required.
Accidental intravascular injection causes systemic
toxicity. e intercostal space is supplied by a rich
network of vasculature and because of the high
metabolic activity of the intercostal muscle, there is
high absorption of local anaesthetic agents leading
to high plasma level and peak sooner than when the
same amount of local anaesthetic agent is injected
elsewhere. us, attention should be paid to the
total dosage of drug used and negative aspiration
confirmed prior to every injection.
e third complication is the development of a
subarachnoid block. is complication has been
reported and proven by dye studies [21]. e dura
occasionally extends out along intercostal nerves for
a variable distance before it adheres to the nerve as
the neurilemma. In this situation, drug deposited in
this potential space can spread into the subarachnoid
and result in spinal anaesthesia, which clinically
presents with sudden and significant hypotension.
is is particularly likely when the point of needle
entry is directed too medially [37].
Suprascapular Nerve Block
Indications
Suprascapular nerve block with local anaesthetic is
used as a clinical diagnostic tool to evaluate shoulder
joint pain [33]. It provides acute pain relief in
postoperative pain for shoulder surgery and pain
due to trauma to the shoulder joint and girdle [10,
16, 29, 40]. Suprascapular nerve block has also been
employed for shoulder and upper extremity chronic
pain conditions, such as rheumatoid arthritis,
frozen shoulder with pain syndrome in reflex
sympathetic dystrophy or adhesive capsulitis to
facilitate a physical rehabilitation programme [36].
Destruction of the suprascapular nerve is indicated
for palliation of cancer pain involving the shoulder
girdle of either primary or secondary origin.
Anatomy
e suprascapular nerve is formed from the C5 and
C6 nerve roots of the brachial plexus. e nerve
leaves the brachial plexus inferiorly and posteriorly
and passes underneath the coracoclavicular
ligament and through the suprascapular notch of
the scapula with the corresponding suprascapular
artery and vein. e suprascapular nerve innervates
the shoulder joint and to a certain extent the motor
supply of the supraspinatus and infraspinatus
muscles (Figure 26.18) [28].
Procedure
e patient is placed in the prone position with
the arms at the side to be blocked. e spine of the
scapula is identified and palpated laterally to the
acromion. With the skin prepared with antiseptic
solution, the point of needle entry is where the
thicker acromion fuses with the thinner scapular
spine. e needle should hit the scapular bone at
a depth of about 2 cm and then gently “walked”
superiorly and medially until the tip walks off
Figure 26.18 Drawing of the posterior of a scapula
showing the anatomy of a suprascapular nerve
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