Ultrasound guided lower extremity block Flashcards
A contraindication with the popliteal block is
fibula & tibia fracture because of the risk of compartment syndrome
Regional anesthesia has many indications including
primary anesthetic post-operative pain management history of severe PONV or risk of MH patient is too ill for general anesthesia physician (surgeon) preference
Absolute contraindications for regional anesthesia include
patient refusal
active bleeding in an anticoagulated patient- not absolute for peripheral more so neuraxial
proven allergy to a local anesthetic
local infection at the site of the proposed block
Relative contraindications to peripheral blocks include
respiratory compromise
inability to cooperate/understand the procedure an anesthetized patient- generally accepted now
bleeding diathesis secondary to an anticoagulant or genetic disorder
bloodstream infection
preexisting peripheral neuropathy
Regional reduces
surgical stress (thus opioid consumption)
overall blood loss?- more so with neuraxial
risk of DVT- more so spinals/epidurals
Regional may be used because
provides anesthesia and/or analgesia (can be titrated)- ability to re-dose with catheter, convert from pain management to primary anesthetic
versatile- control extent of sensory & motor blockade, used with or without adjunct medications
In order for exparel to be effective for a procedure,
it needs to be mixed with regular bupivacaine so you can get short term coverage
Prior to beginning any procedure:
verify the correct patient obtain informed consent verify the correct procedure verify the correct extremity gather all necessary equipment place the patient on oxygen obtain baseline VS and monitor during the procedure administer proper/adequate sedation
Necessary block supplies include
sterile gloves 4x4 nerve stimulator anti-microbial stimulating needle local of choice with possible additive local for subcutaneous infection
For local anesthetics, most references recommend
20-40 mLs/block
some authors have demonstrated successful, complete blocks with much lower volume
Amount & type of local anesthetic depends on
patient factors-maybe they have an allergy?
timing of the procedure
procedure itself- maybe the procedure is really short and we don’t want them to have motor loss for 8 hours
purpose of the block- primary anesthetic vs. analgesia
The most commonly used amide is
bupivacaine because it is cheap
also most likely to cause last
The Lumbar/lubosacral plexi provides nerve innervation to
the lower extremity
The lumbar plexus arises from
nerve roots L1-4 and occasionally T12
The lumbar plexus includes the following nerves:
ilioinguinal, iliohypogastric, lateral femoral cutaneous, femoral (saphenous) and obturator nerves
The lumbosacral plexus arises ffrom
nerve roots L4-5 and S1-3
The lumbosacral plexus includes the
sciatic nerve (tibial, peroneal, and nerves of the ankle/foot)
The lateral femoral cutaneous nerve is
just sensory with no motor innervation
Lower extremity blocks that are considered lumbar plexus blocks include
femoral
fascia iliaca
adductor canal
saphenous (thigh & ankle)
Lower extremity blocks that are considered lumbosacral plexus blocks include
sciatic (subgluteal)
sciatic (popliteal level)
iPACK
ankle blocks
The lumbar plexus supplies
sensory and motor innervation to the thigh, anterolateral knee, and sensory innervation to the medial aspect of the lower extremity below the knee
The femoral nerve block targets
the major branch of the lumbar plexus
The femoral nerve block provides anesthesia to the
anterior thigh, knee, and medial aspect of lower leg
The femoral nerve can be found
lateral to the artery and deep to the fascia lata & iliaca, and superior to the iliopsoas muscle
The USG technique for the femoral nerve block includes
patient supine with slight external rotation of extremity
transducer placed over inguinal crease, over femoral pulse
high-frequency linear array transducer
short-axis image, in-plane needle insertion (lateral to medial)
nerve is a hyperechoic ovoid lateral to femoral artery, beneath fascia lata and iliaca
5 cm B-bevel needle
20 mLs of local anesthetic
If they want patient to walk then we would avoid
a femoral nerve block because we get quadriceps weakness
The needle approach for the femoral nerve block is
lateral to medial
____________ is elicited when nerve stimulation is used with ultrasound
Patellar snap
Femoral nerve block pearls include
doppler can be used to verify flow in the femoral vessels
if two arteries are visible, scan cephalad until a single femoral artery is identified
local anesthetic placed below fascia lata and iliaca results in greatest efficacy
lymph nodes in the groin may appear as “nerves” a pre-procedure scan will help distinguish them
Describe how to assess whether it is a nerve or lymph nodes.
lymph nodes are not continuous like nerves
lymph nodes are above the fascia plane
The ultrasound guided fascia iliaca block is
similar to an USG 3 in 1 lumbar plexus block because it targets:
femoral nerve
obturator nerve
lateral femoral cutaneous nerve
The USG fascia iliaca block uses (volume)
increased volume (40 mL) to block all three nerves it is considered a volume block
The ultrasound imaging for the fascia iliaca block
is similar to that of the femoral nerve block
A disadvantage of the fascia iliaca is
quadriceps weakness which limits ability to ambulate
The adductor canal block is utilized for
total knee arthroplasty because it decreases hospitalization and narcotic administration while still allowing for ambulation
The ________ has been the gold-standard for pain relief following TKA
femoral nerve block
- it is associated with risk of falls due to quadriceps weakness
The adductor canal block was first used as
a means to identify the saphenous nerve using the superficial femoral artery/vein as landmarks
The femoral triangle is considered to be
medial aspect of the sartorius
medial aspect of adductor longus
inguinal ligament
The adductor canal describes an
intermuscular tunnel in the anteromedial thigh that lies posterior to the sartorius msucle
The proximal origin of the adductor canal is the
femoral triangle and it terminates at the adductor hiatus
Studies consistently demonstrate that _____________ pass through the canal in the adductor canal block
saphenous nerve and the nerve to the vastus medialis
The USG technique for the adductor canal block is to
have the patient supine with slight external rotation of extremity
transducer placed mid to distal third of thigh
high-frequency linear array transducer
short-axis image, in plane needle insertion
LA deposited in the fascial plane separating the sartorius and vastus medialis lateral to the femoral vessels
Adductor canal block pearls include
nerve branches may be located on both sides of the superficial femoral artery
a pre-procedure scan will detect any aberrancies and increase block efficacy
case reports demonstrate that if local anesthetic is deposited within the muscle, myotoxicity may occur
The adductor canal block will not
cover any posterior nerve
The saphenous nerve is the
terminal branch of the femoral nerve
The saphenous nerve is
distal to the adductor canal
courses superficially in the distal thigh
The saphenous nerve provides
sensory innervation to the medial aspect of lower extremity below the knee
The saphenous nerve block is used
in conjunction with other blocks for surgical procedures involving the ankle & foot
The USG technique for the saphenous nerve block is
patient supine with slight external rotation of extremity
transducer placed at distal thigh
high-frequency linear array transducer
short-axis image, in-plane needle insertion
LA deposited in the fascial plane separating the adductor longus and vastus medialis below the subcutaneous tissue
inject 5-10 mL of local anesthetic
The lumbosacral plexus supplies
sensory and motor innervation to the posterior thigh, knee, and the lower extremity below the knee with exception to sensory innervation provided by the saphenous nerve
The sciatic block is also known as
the subgluteal
The sciatic nerve runs
deep to the gluteus maximus between ischial tuberosity and greater trochanter
The sciatic block results in
sensory and motor blockade of the entire lower extremity below the knee except for sensory innervation of the medial lower extremity below the knee (saphenous)
______ may be missed with the subgluteal approach
the posterior thigh which is innervated by femorocutaneous nerve
Describe the technique for the sciatic block
patient prone or lateral
low-frequency curvilinear array transducer placed just distal to the gluteal crease
short-axis image, in-plane needle insertion
local anesthetic deposited in the fascial plane separating the adductor longus and vastus medialis below the subcutaneous tissue
inject 20 mL of local anesthetic
The popliteal nerve block targets the
sciatic nerve slightly above the knee
The sciatic branches into the
tibial (course medial) and common peroneal nerves (lateral)
In the popliteal fossa, they are bordered superiorly and medially by the
semi-tendinosus and semi-membransosus muscles and superiorly and laterally by the biceps femoris muscle
Describe the USG technique for the popliteal nerve block.
patient supine with operative leg elevated
high frequency linear array transducer
transducer is placed in the popliteal crease
short-axis image distal of the tibial and peroneal bifurcation
the tibial nerve is superior to the popliteal artery and vein, scan proximal to locate the bifurcation with the peroneal nerve
With the popliteal nerve block, the needle is inserted
in-plane lateral to medial
Popliteal block pearls include
scan the proximal and distal to appreciate the anatomy
the transducer may have to be angled toward the foot to better image the nerves
circumferential spread around each nerve ensures a dense block
Describe an IPACK block
infiltration between the popliteal artery and posterior capsule of the knee to block terminal branches innervating the joint, sparing distal innervation of the tibial and peroneal branches
The IPACK block is an alternative to
a sciatic block and selective tibial nerve block for controlling pain following knee arthroplasty
avoids blocking the motor nerve
Indications for the IPACK block include
posterior knee pain control for total knee arthroplasty
-preserves or minimally reduces foot drop, facilitates post-op ambulation and rehabilitation
The technique for the IPACK block is to
place patient in lateral decubitus position
transducer placed in transverse plane above the popliteal crease
identify space between- popliteal artery and vein & intercondylar notch
needle inserted lateral to medial
15-20 mL local anesthetic injected while slowly withdrawing needle
The five nerves that supply innervation to the foot include
tibial nerve deep peroneal nerve superficial peroneal nerve saphenous nerve sural nerve
USG ankle blocks are routinely indicated for
surgical anesthesia & postoperative analgesia involving the foot
Regional anesthesia complications include
LAST
paresthesia or nerve injury
bleeding & infection
intravascular puncture/injection
