Chapter 76 Truncal Blocks: Intercostal, Paravertebral, Interpleural, Suprascapular, Ilioinguinal, and Iliohypogastric Nerve Blocks Flashcards
KEY POINTS 1. When compared to epidural analgesia for thoracotomy, paravertebral blocks with catheters provide equipotent analgesia with a lower incidence of pulmonary complications, hypotension, urinary retention, nausea and vomiting, and failure rate. 2. A single injection of 15 ml in a thoracic paravertebral space can be expected to provide analgesia over 3 to 4.6 dermatomes, with a preferential caudad spread of injectate. 3. Ultrasound imaging usually underestimates the distance to the tr
Epidural analgesia when compared to
paravertebral blocks for patients undergoing thoracotomy
fewer side effects including
pulmonary complications, hypotension, urinary
retention, and nausea and vomiting.
paravertebral (PV) space
wedge-shaped area adjacent
to the vertebral column that contains the sympathetic
chain, the dorsal and ventral (intercostal) roots of the spinal
nerve, the white rami communicantes as well as fatty
tissue and intercostal vessels
The base of the wedge constitutes
the medial border of the paravertebralspace and is formed by the vertebral body and the intervertebral
disc where there is communication with the epidural space via the intervertebral foramen
The posterior border of the PV space
the superior costotransverse ligament which extends laterally to become continuous with the aponeurosis of the internal intercostal muscle.
internal intercostal membrane runs
between the ribs
superior costotransverse ligament runs from
the inferior border of the transverse process above to the superior border of the rib tubercle below.
As the wedge tapers off
laterally, it is continuous with the
intercostal space
Anterior and lateral to the PV space is the
parietal pleura
Within the paravertebral space, the spinal nerves
do not have a fascial sheath and are easily susceptible
to local anesthetic blockade. There is however the endothoracic fascia, which is the deep investing fascia of the
thoracic cavity, within the PV space that can affect the
spread of injected solutions.
Conventional techniques have described
loss-of-resistance approach to reach the PV space. A small-gauge Tuohy needle is inserted 2.5 cm lateral to the
superior edge of the spinous process perpendicular to all
planes and advanced until contact is made with the transverse process (TP). The needle is then withdrawn to the skin, redirected caudad or cephalad by 15 degrees and advanced deep to the superior costotransverse ligament at which point loss of resistance is achieved. To avoid pleural puncture, the needle
is advanced 1 cm (and no further than 1.5 cm) past the point at which the TP was contacted
It is best to avoid medial and lateral angulation of the needle to minimize the risk of
It is best to avoid medial
angulation of the needle to minimize the risk of local
anesthetic injection into a dural sleeve. It is also prudent to
avoid lateral angulation given that the PV space is narrower
laterally increasing the risk of pleural puncture
Three US-guided approaches have been described.
The first approach utilizes US primarily to identify
the TP.
Once the TP is contacted under US guidance, the conventional loss-of-resistance technique is utilized. To visualize the TP, the US probe is placed in a longitudinal
parasagittal plane 2.5 cm from the midline. Generally, a 5- to 10-degree tilt laterally is needed to best visualize the TP, which appears as concave hyperechoic structure
approximately 1 cm wide with anechoic space deep to
it. This is commonly referred to as a “thumbprint sign.”
The parietal pleura can be visualized approximately 1 cm
deep to the TP on either side as a sharp hyperechoic line. Initial contact with the TP should be made with a 22-gauge finder needle that can serve to infiltrate local anesthetic. Generous local anesthetic infiltration is recommended to minimize paraspinal muscle discomfort and can serve to echolocate the needle tip. Once the TP is contacted with the finder needle, the depth is noted and a Tuohy needle or blunt-bevel block needle is introduced. Using an out-of-plane needle approach and similar to the
conventional technique, the TP process is contacted and
then redirected caudad 1 cm (and no more than 1.5 cm)
past the TP. Loss of resistance to saline is confirmed and
local anesthetic injection is performed
The first approach utilizes US primarily to identify the TP. To minimize the risk of pleural puncture and development of pneumothorax,
it is useful to have a needle with centimeter markings and a closed needle-syringe system relative to atmospheric pressure.
The second approach is a slight variation of the first and
utilizes an in-plane or out-of-plane approach to the PV
space
The probe is in the identical longitudinal parasagittal
plane and the PV space is approached directly without first contacting the TP process. a “pop” may be felt when the posterior costotransverse ligament is traversed with corresponding loss of resistance
In the third approach, the TP is initially imaged with
a similar longitudinal parasagittal view, and the probe is then rotated obliquely to allow for the best view of the posterior costotransverse ligament and the PV wedge. The needle is advanced carefully utilizing an in-plane needle approach
PV Block DOSING
A single injection of 15 ml can be expected to provide analgesia over 3 to 4.6 dermatomes in the thoracic region. Spread is initially at the level of injection and
along the intercostal nerve, and progresses in the PV “gutter” to cover one dermatome above and two dermatomes
below.
PV Block Analgesia last for
typically ranges from 6 to 12 hr for a single injection. If a catheter is placed, infusion
of ropivacaine 0.2% to 0.5% at rates of 4 to 8 ml/hr may
be used
PV Block COMPLICATIONS
Pneumothorax is estimated to occur in up to 0.5% of
patients, yet most are not clinically significant and can be
managed conservatively. most
patients will present with a sudden irritating cough or
sharp pain in the chest. Vascular puncture
If the parietal pleura is violated, the
block can be converted
to an intrapleural block
Life-threatening complications from PV blocks
have occurred as a result of bolus dosing. A bolus dose can accidentally be injected into the intrathecal or epidural
space, or into a blood vessel. bolus dosing with subsequent intrathecal or intravascular
spread—and not pneumothorax
intercostal blocks can be used to provide chest
wall analgesia In patients with
spinal anomalies, trauma, or previous spine surgery
INTERCOSTAL NERVE BLOCK
ANATOMY
As nerves leave the PV space, they enter the intercostal
space and lie between the innermost intercostal muscle
and the pleura
primary landmark for intercostal nerve block
Lateral to the paravertebral muscles, the prominent angles of the ribs are palpable
At the angle of the
rib, the nerve lies between
the innermost intercostal muscle
and the inner intercostal muscle
Classically the intercostal nerves
have been thought to lie
caudad to the intercostal vein and artery, on the inferior portion of the rib.
Most of the T1 nerve fibers combine with
C8 to form the lower trunk of the brachial plexus.
form the intercostobrachial nerve that supplies the upper chest wall along with cervical fibers
from the brachial plexus.
Fibers from T2 and T3
Intercostal nerves T4–T11 supply
the
thoracoabdominal wall from the nipple line to below the umbilicus.
The T12 nerve is actually a subcostal nerve that contributes branches to the
iliohypogastric and
ilioinguinal nerves
INTERCOSTAL NERVE BLOCK
TECHNIQUE
(Patient’s position)
The ideal patient position is prone, with a pillow under the
abdomen and both upper extremities hanging over the sides of the table, which maximizes retraction of the scapulae away from the upper ribs. This allows for bilateral blockade and posterior access to the angles of the ribs to enhance safety and success of the procedure. The lateral decubitus position is also quite satisfactory for unilateral blockade after rib fractures and lateral thoracotomy as well as for chest tube placement. The supine position may also be utilized
for bilateral block at the level of the midaxillary line;
however, the rib and intercostal space are narrower here
INTERCOSTAL NERVE BLOCK
Classic TECHNIQUE
locating the angle of the rib (approximately 8 cm lateral to the midline) and using a 22-gauge, short-bevel needle to walk off 3 mm deep
to the lower costal margin, and repeating this at the desired
levels.
INTERCOSTAL NERVE BLOCK
TECHNIQUE
US
US imaging is used to identify the space between the internal and innermost intercostal muscles 8 cm lateral to the spinous process, and D5W or saline can be injected to confirm needle tip position in the fascial
plane and anterior pleural displacement.
INTERCOSTAL NERVE BLOCK
DOSING
A single-shot intercostal block can be expected to provide
analgesia for only 6 to 8 hours.
INTERCOSTAL NERVE BLOCK
COMPLICATIONS
Total spinal anesthesia by injection into a dural sleeve is a rare but dangerous complication. Local anesthesia
toxicity as a result of bolus dosing may occur due to
rapid uptake from the well vascularized intercostal space.
Also, pneumothorax and liver subcapsular hematoma formation
are potential complications.
Intrapleural block may be used to provide
unilateral chest wall analgesia during and after cholecystectomy, renal,
breast, or thoracic surgery, as well for treatment of upper
extremity ischemic and neuropathic pain, thoracic herpes zoster, pancreatitis, and thoracic cancer pain.
When compared
to intercostal blockade, intrapleural block produces
analgesia that is
less intense and of shorter duration
The visceral layer of pleura
surrounds the lung and reflects
back on the chest wall and diaphragm to form the parietal
pleura.
The intrapleural space
a potential site for local
anesthetic administration. Local anesthetics may block
free nerve endings in the pleura and diffuse across the
pleura to act on adjacent nerves
Nerves around the pleura
The intercostal nerves are
present posteriorly and laterally, while the splanchnic
nerves, sympathetic chain, phrenic and vagus nerves are
medial to the pleura. The lowest roots of the brachial
plexus pass superiorly, over the cupola of the lung.
INTRAPLEURAL BLOCK
POSITIONING
The ipsilateral arm should hang across the body or off the table
to retract the scapula anteriorly.
The endpoint for entry
into the intrapleural space is
detection of negative intrapleural pressure, which is present during spontaneous
ventilation. Placement should be avoided during controlled
ventilation to prevent catheter misplacement, lung injury, and pneumothorax.
The site for catheter insertion is selected
from the fifth through eighth intercostal spaces
INTRAPLEURAL BLOCK
TECHNIQUE
a skin wheal is raised immediately superior to the selected rib, approximately
8 to 10 cm lateral to the midline. A 17- or 18-gauge
epidural needle is then inserted at the same site, with its bevel aimed in the direction of intended catheter insertion. The epidural needle is placed perpendicular to the skin, over the rib, and walked cephalad until contact with the
superior edge of the rib is lost. Before slowly advancing the
needle further, the needle stylet is removed, and a glass
syringe containing approximately 2 ml of saline is attached. The entry into the pleural space is identified using passive loss-of-resistance technique. When the needle tip is in the
pleural space, the negative intrapleural pressure pulls
down the syringe plunger and contained saline, and injection
will be easy. The intrapleural catheter should be threaded approximately 5 to 10 cm into the pleural space, taking care to reduce air entrained through the needle.
Injection with
the operative side uppermost favors
medial spread of solution
and unilateral sympathetic block.
Injection in the supine position favors blockade of
the intercostal nerves with less sympathetic block.
The block is then
performed on the left side for
pancreatic, gastric, or splenic
pain and on the right side for hepatic or gallbladder pain
INTRAPLEURAL BLOCK
DOSING
A therapeutic dose of 20 to 30 ml of 0.25% to 0.5% bupivacaine is delivered over 2 to 3 min, and patient
position is subsequently maintained for 20 to 30 min during which time a chest tube should be clamped if present.
Repeated bolus doses may be given every 6 hours, or as
needed. A continuous infusion of 0.25% bupivacaine at
0.125 ml/kg/hr produced better analgesia after cholecystectomy, with lower blood levels, than intermittent bolus dosing
INTRAPLEURAL BLOCK
COMPLICATIONS
Complications from this procedure can be divided into
two categories
those produced by traumatic injuries of either the needle or the catheter and those produced by systemic absorption of local anesthetic solution injected in the intrapleural space. Pneumothorax may occur. Systemic effects from
drug absorption may occur, particularly with inflammation
of pleural membranes. Local anesthetic toxicity. Pleural
effusion, Phrenic nerve palsy, bronchopleural fistula formation, empyema, and injury to the neurovascular
bundle may also occur following this block.
neumothorax or catheter malposition
appear to be more likely with use of
sharper needles, stiffer
epidural catheters, and positive-pressure ventilation during
needle and catheter placement.
INTRAPLEURAL BLOCK
The following steps
may minimize catheter-related risks:
slow introduction of a soft, flexible tip catheter; use of a blunt epidural needle; and use of a heavy glass syringe barrel to better detect entry into the intrapleural space
occurs often after successful
intrapleural block.
Horner’s syndrome
Suprascapular nerve block (SSNB) is indicated for
elief of acute and chronic pain in the shoulder, which may be due to bursitis, capsular tear, periarthritis, or arthritis
The suprascapular nerve originates from
the superior trunk of the brachial plexus (C4–C6), crosses the posterior triangle of the neck, and passes deep to the trapezius
muscle.
suprascapular nerve traverses the
suprascapular notch and
descends deep to the supraspinatus and the infraspinatus muscles, supplying the two muscles and about 70% of the shoulder joint.
suprascapular nerve Sensory innervation includes the
posterior and posterosuperior regions of the shoulder joint and capsule, and the acromioclavicular joint
SUPRASCAPULAR NERVE BLOCK
POSITIONING
The patient is positioned sitting, preferably with the arms
folded across the abdomen. A line is drawn along the spine
of the scapula from the tip of the acromion to the scapular
border. The midpoint of this line is noted, and a vertical
line, parallel to the vertebral spine, is drawn through it.
The angle of the upper outer quadrant is bisected with a
line; the site of insertion of the needle is 2.5 cm from the
apex of the angle
SUPRASCAPULAR NERVE BLOCK
TECHNIQUE
A 3-inch (7.5 cm), 22-gauge needle is inserted perpendicular to the skin in all planes. After contacting bone (i.e., the area surrounding the suprascapular notch) at approximately 5 to 6.5 cm, the needle is slightly withdrawn and redirected as needed until it slides into the notch. Up to 10 ml of local anesthetic is injected
SUPRASCAPULAR NERVE BLOCK
confirms successful
block
No skin analgesia results from the block. Weakness of external shoulder rotation
SUPRASCAPULAR NERVE BLOCK Complications
Pneumothorax may occur in less than 1% of cases
SUPRASCAPULAR NERVE BLOCK
ULTRASOUND GUIDANCE
The patient is positioned sitting. A high-frequency US
probe is placed over the scapular spine in transverse orientation,
and the suprascapular fossa with the supraspinatus
muscle above it are scanned. Slight lateral movement will
bring into view the suprascapular notch. The SSN is visualized
as a hyperechoic structure beneath the transverse
scapular ligament, in the suprascapular notch
Ilioinguinal and iliohypogastric nerve blocks may be used
in the diagnosis and treatment of chronic suprapubic and
inguinal pain after lower abdominal surgery or hernia repair. They may be combined with genitofemoral nerve
block. These blocks may be applied in the management
of patients with neuralgias and nerve entrapment syndromes
typically performed for inguinal herniorrhaphy.
Iliohypogastric and ilioinguinal nerve blocks are also important components of regional anesthesia of the
inguinal region
Bilateral ilioinguinal nerve block with 0.5%
bupivacaine
decreased analgesic requirements and pain
scores for 24 hr after cesarean section performed under
general anesthesia
The iliohypogastric (T12–L1) and ilioinguinal (L1) nerves emerge from
the lateral border of the psoas major muscle, travel around the abdominal wall, and penetrate the transverse
abdominal and the internal oblique muscles to innervate
the hypogastric and inguinal areas
The anterior
cutaneous branch of the iliohypogastric nerve passes
through the internal oblique muscle just medial to the
anterior superior iliac spine (ASIS), to lie next to the external oblique muscle. It then passes through the external oblique above the superficial inguinal ring, and supplies
the suprapubic area.
The ilioinguinal nerve course
remains between the deeper two muscle layers, it travels through the inguinal canal and supplies the upper medial thigh and
superior inguinal region
An effective block of both nerves, ilioinguinal nerve and iliohypogastric nerve
performed medial to the ASIS must be made at multiple
depths, in various fascial planes.
The genitofemoral
(L1–L2) nerve
passes through and along the anterior surface of the psoas major muscle, and it divides into genital and femoral branches above the inguinal ligament. Its genital branch travels with the spermatic cord and innervates
the genitalia inferior to the area supplied by the ilioinguinal nerve.
ILIOINGUINAL AND ILIOHYPOGASTRIC
NERVE BLOCKS
positioning
The patient is positioned supine, with a pillow under
knees. The primary anatomic landmark is the ASIS, identified
by palpation.
ILIOINGUINAL AND ILIOHYPOGASTRIC NERVE BLOCKS TECHNIQUE
The injection site is about 2 inches medial and 2 inches cephalad to the ASIS. A 25-gauge, 1.5-inch needle is inserted perpendicular to the skin, noting the double pop feeling when each layer of fascia is penetrated. Infiltration with about 10 ml of local anesthetic is performed at each depth and, subsequently, fanned
in the area.
The genital branch of the genitofemoral nerve
block can be blocked by infiltration
of 5 to 10 ml of local
anesthetic, using a 25-gauge, 1.5-inch needle inserted just
lateral to the pubic tubercle and below the inguinal ligament. Infiltration around the spermatic cord at its exit
from the inguinal canal is also an effective technique
ILIOINGUINAL AND ILIOHYPOGASTRIC
NERVE BLOCKS
Ultrasound Guidance
The patient is positioned supine, and a high-frequency US probe is placed superior and medial to the ASIS, on an imaginary line uniting the ASIS and the umbilicus. The nerves are usually visualized between the internal oblique and transversus muscles. An in-plane technique provides optimal access to the ilioinguinal and
iliohypogastric nerves; hydrodissection may be useful to better delineate the narrow fascial plane. Small vessels, including the deep circumflex iliac artery, identified with color Doppler, may be present in the fascial plane. Deep to the transversus muscle the parietal peritoneum and bowel
can be identified
ILIOINGUINAL AND ILIOHYPOGASTRIC
NERVE BLOCKS
COMPLICATIONS
ecchymosis, hematoma, visceral perforation, systemic toxicity, and infection. Accidental block of the lateral femoral cutaneous nerve and partial block of the femoral nerve
may also occur.
The transversus abdominis plane (TAP) block
uses anatomic landmarks
to approach the plane through the triangle of Petit
The triangle of Petit
bordered by latissimus dorsi posteriorly, the external oblique muscle anteriorly, and the ASIS as base of the triangle.
The innervation of the anterior
abdominal wall is provided by
the anterior rami of the T7–T12 and L1 nerves, whose terminal branches are coursing in the fascial plane between the internal oblique and the transversus abdominis muscle, the transversus abdominis plane.
TRANSVERSUS ABDOMINIS PLANE
BLOCK
anatomic landmarks TECHNIQUE
the TAP is accessed through
the triangle of Petit. A “double-pop” technique is used to confirm the needle passage through the external oblique fascia, followed by the passage through the fascial
plane between the internal oblique and the transversus
abdominis muscles.
TRANSVERSUS ABDOMINIS PLANE
BLOCK Ultrasound Guidance
The three muscle layers, the external oblique, internal oblique, and transversus abdominis, and needle insertion plane, between the internal oblique and transversus abdominis muscles, can be easily vizualized when the probe is placed above the ASIS.60 An inplane or out-of-plane technique can be used. Hydrodissection of the plane may facilitate accurate placement of the needle. Fifteen to 20 ml of local anesthetic are typically
used on each side
Ultrasound-guided TAP blocks have been used to provide
postoperative analgesia for
lower abdominal surgeries,
including inguinal hernia repair, cesarean section and retropubic prostatectomy. A subcostal approach has been
described for laparoscopic cholecystectomy. It has also
been used to provide postoperative analgesia for other upper abdominal surgeries, including laparoscopic surgeries such as appendectomy and incisional hernia repair
