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USRA OF THE
LOWER EXTREMITY
Christian R. Falyar, CRNA, DNAP
Department of Nurse Anesthesia
Virginia Commonwealth University
Disclosure Statement of
Financial Interest
• I, Christian Falyar,
DO NOT have a financial
interest/arrangement or affiliation with
one or more organizations that could
be perceived as a real or apparent
conflict of interest in the context of the
subject of this presentation.
Disclosure Statement of
Financial Interest
• I, Christian Falyar,
DO NOT have a financial
interest/arrangement or affiliation with
one or more organizations that could
be perceived as a real or apparent
conflict of interest in the context of the
subject of this presentation.
Disclosure Statement of
Unapproved/Investigative Use
I, Christian Falyar,
DO NOT anticipate discussing the
unapproved/investigative use of a
commercial product/device during this
activity or presentation.
Objectives
Lower Extremity Blocks
•  State the indications for each lower extremity
•  Lumbar Plexus
•  Femoral
•  Adductor Canal
•  Saphenous (thigh and ankle)
block
•  Describe the ultrasound landmarks for each lower
extremity block
•  Review the ultrasound-guided needle insertion
plane and local anesthetic requirements for each
lower extremity block
•  Discuss the side-effects and complications
related to lower extremity blocks
•  Sacral Plexus
•  Sciatic (gluteal level)
•  Sciatic (popliteal level)
•  Ankle Blocks
•  Tibial
•  Peroneal (Deep and Superficial)
•  Sural
Indications
Contraindications
•  Regional anesthesia has many indications,
•  In certain instances regional anesthesia should
including:
 Primary anesthetic
not be considered. Absolute contraindications
include:
 Pain Management
 Patient refusal
 History of severe PONV or risk of MH
 Local infection at the site of the proposed block
 Patient is too ill for general anesthesia
 Active bleeding an anticoagulated patient
 Surgeon preference
 Proven allergy to a local anesthetic
Contraindications
Pre-Procedure
•  Most contraindications to regional anesthesia are
•  Prior to beginning any procedure:
 Verify the correct patient
 Obtain informed consent
 Verify the correct procedure
 Verify the correct extremity
 Gather all equipment
 Place the patient on oxygen
 Obtain baseline VS and monitor during the procedure
 Administer proper/adequate sedation
relative. The provider must determine the risk
vs. benefit.
 Respiratory compromise
 Inability to cooperate/understand procedure
 An anesthetized patient (adult population)
 Bleeding diathesis secondary to an anticoogulant or
genetic defect
 Bloodstream infection
 Preexisting peripheral neuropathy
Complications
Local Anesthetics
•  Regional anesthesia can result in complications
 Local anesthetic toxicity
•  How much is enough?
•  Most references recommend 20-40 mLs per block
•  Some authors have demonstrated successful, complete blocks with
less volume
 Intra-arterial injection
•  Amount and type of local anesthetic depends:
such as:
 Respiratory compromise
•  Patient factors
 Parathesias and nerve damage
•  Timing of the procedure
•  Risks and benefits of regional anesthesia should
always be discussed beforehand
•  Procedure
•  Purpose of the block
Local Anesthetics
Femoral Block
•  The femoral block targets the major branch of the
Drug
Max Dose (mg/kg)
Lidocaine*+ Drug
4.5mg/kg
Max Dose with Epi (mg/kg)
Max Dose (mg/kg) 7mg/kg Max Dose with Epi (mg/kg)
Lidocaine*
Mepivacaine*+
4.5mg/kg
4mg/kg
7mg/kg
Mepivacaine*
2.5mg/kg
4mg/kg
N/A
Bupivacaine*
Bupivacaine*
2.5mg/kg
7mg/kg
3.2mg/kg
Ropivacaine*
5mg/kg
Procaine+
Procaine+
12mg/kg
12mg/kg
N/A
Chloroprocaine*
Chloroprocaine*
11mg/kg
11mg/kg
14mg/kg
14mg/kg
Prilocaine*
Prilocaine*
8mg/kg
7mg/kg
8.5mg/kg
8.5mg/kg
Tetracaine+
3mg/kg
3mg/kg
N/A
Ropivacaine*
Tetracaine+
3mg/kg
N/A
7mg/kg
3.5mg/kg
N/A
lumbar plexus
•  Provides anesthesia to the anterior thigh, knee
and a small part of the lower leg
•  The nerve is lateral to the femoral artery and
deep to the fascia lata and iliaca, and superior to
the iliopsoas muscle
N/A
5th
* - Nagelhout & Plaus,
ed., pg. 137
+ - Morgan & Mikhail, 5th ed., pg. 272
Femoral Anatomy
USRA Technique
•  Pt. supine with slight external rotation of femur
•  Transducer is placed at the inguinal crease, over
Fascia iliaca
Fascia lata
the femoral pulse
•  High-frequency linear array transducer
•  Short-axis image, needle inserted in-plane
•  Femoral nerve is a hyperechoic circle that lies
lateral to the femoral artery
•  5 cm B bevel needle is used
•  20 to 30 cc’s of local anesthetic injected
Pre-Procedure Scan
USRA Technique
•  Needle approach is lateral
to medial
FL
•  Nerve stimulation can be
used with ultrasound;
“patellar snap”
•  Major benefit of real-time
imaging is visualizing
needle movement and
local anesthetic spread
USRA Technique
FN
FA
FI
IPSM
Femoral
•  If more than one artery is visible, scan cephalad
and identify a singular femoral artery
•  Doppler can be used to verify femoral vessels
•  Experience suggests that if the needle and the
local anesthetic are placed below the fascia iliaca
and lateral the artery, successful blocks occur
despite the lack of twitches
Femoral
Too low
Femoral
Just right
•  Complications such as vascular puncture and
local anesthetic injection are best avoided by
observing the needle tip throughout the procedure
•  Lymph nodes in the groin appear as “nerves”;
scanning proximal and distal will help distinguish
the lymph node as they are not continuous and
can be seen only at specific locations
Femoral
Adductor Canal
•  The femoral nerve block (FNB) has been the
gold-standard for pain relief following TKA
•  Although effective for pain relief, it is associated
with risk of falls
•  Adductor canal block provides sensory nerve
blockade with minimal motor involvement
Adductor Canal Anatomy
USRA Technique
•  Pt. supine, with slight external rotation of the
Rectus
Femoris
Adductor
Canal
Vastus
Medialis
Adductor
Longus
Adductor Canal
Gracilis
Sartorius
operative leg
•  High frequency linear array transducer placed midthigh in short axis orientation
•  The superficial femoral artery and vein appear as
hypoechoic circles bordered superiorly by the
sartorius, laterally by the vastus medialis and
medially by the adductor longus muscles
•  Needle inserted using in-plane image
•  Up to 20 mL of local anesthetic injected in the fascial
plane bordering the superficial femoral artery
Adductor Canal
•  Studies show consistent nerve identification and
Sartorius
Vastus
Medialis
Adductor
Longus
block success (100%), owing to the large
hypoechoic superficial femoral artery and vein
•  The vastus medialis will be blocked in some
patients, however the clinical significance is not
completely known
Saphenous (thigh)
Saphenous Anatomy (thigh)
•  Saphenous block at the thigh is used as an
adjunct to a popliteal block for lower extremity
surgery below the knee
USRA Technique
•  Pt is supine with lower extremity slightly abducted
•  Transducer placement is dependent on the method used
to identify the nerve
•  High frequency transducer
•  Short-axis image, needle inserted in-plane
•  Saphenous nerve is a hyperechoic circle that lies in the
fascial plane between the sartorius and vastus medialis
muscles
•  5 – 10cm needle is used
•  10cc’s of local anesthetic injected
Pre-Procedure Scan
Pre-Procedure Scan
Saphenous (thigh)
saphenous nerve
vastus medialis
Saphenous (thigh)
Saphenous (thigh)
•  There are few complications associated with this
block
Sciatic
Sciatic
•  Sciatic nerve arises from L4-5 and S1-3
•  Indicated for surgical procedures of the hip, thigh,
posterior knee, lower leg and foot.
•  Anatomical knowledge is paramount; locating
needle with landmark or US may be difficult.
Sciatic
Popliteal
•  Gluteal contraction indicates the needle must be
•  Targets the sciatic nerve slightly above the knee
advanced further
•  Complications include:
•  Provides anesthesia for procedures involving the
•  Intraneural injection
•  Intravasuclar injection
foot and ankle
•  In the popliteal fossa, the sciatic is bordered
superiorly and medially by the semi-tendinosus
and semi-membranosus muscles and superiorly
and laterally by the biceps femoris muscle
Popliteal Anatomy
Ultrasound Technique
•  Prone, supine, or lateral position
•  High frequency linear array transducer
•  Transducer is placed in the popliteal crease
•  Short-axis, in-plane or out-of-plane
•  The sciatic nerve is superior to the popliteal artery
and vein, then bifurcates in the tibial (larger), and
peroneal (more lateral).
•  5 or 10 cm needle
•  up to 30 cc’s of local anesthetic injected
incremental with negative aspiration
Popliteal
Prone
Pre-Procedure Scan
Supine
Popliteal
Popliteal
•  Ultrasound greatly reduces the traditional
complications of intravascular and intra-neural
injections
•  When using nerve stimulation, dorsal or plantar
flexion is acceptable
•  Complications include:
•  Intravascular injection
•  Intraneural injection
Popliteal
Ankle
•  Five nerves are blocked in
•  Scan the proximal and distal to appreciate the
anatomy
•  The transducer may have to be angled toward to
the foot to better image the nerves
•  Circumferential spread around the nerve ensures
a dense block
the ankle
•  Femoral
•  saphenous
•  Sciatic
•  tibial
•  sural
•  deep peroneal
•  superficial peroneal
Ankle Anatomy
Ankle
Ultrasound Technique
Posterior Tibial
•  Supine with foot elevated or extended past the
end of the stretcher
•  High frequency linear array transducer
•  Short-axis, in-plane or out-of-plane
•  Corresponding vascular structure identified first
•  5 cm B bevel needle
•  3-5 mL of local anesthetic injected following
negative aspiration to achieve circumferential
spread
Deep Peroneal
Superficial Peroneal
Sural
Saphenous
Ankle Blocks
•  Aggressive injections of large volumes of local anesthetic
can cause hydrostatic damage to small nerves such as
the deep peroneal nerve because it is enclosed in
ligamentous spaces
References
•  Chan V., & Pollard B.; An Introductory Cirriculum for Ultrasound-
Guided Regional Anesthesia; 2009, University of Toronto Press.
•  Chan, Vincent; Ultrasound Imaging for Regional Anesthesia: A
Practical Guide; 3rd Edition; 2010, Toronto Printing Company.
•  Gray, Andrew; Atlas of Ultrasound-Guided Regional Anesthesia; 2007,
Saunders/Elsevier.
•  Hadzic, Admir; Textbook of Regional Anesthesia and Acute Pain
Management; 2007, McGraw-Hill Medical.
•  Morgan, G., & Mikhail, M.; Clinical Anesthesiology; 4th Edition; 2006,
McGraw-Hill Medical.
•  Sites, B., & Spence, B.; Ultrasound Guidance in Regional Anesthesia:
Techniques for Upper-Extremity and Lower-Extremity Nerve Blocks;
2008, McMahon Publishing.
•  Zwiebel, W., & Pellerito, J.; Introduction to Vascular Ultrasonography;
5th Edition; 2005, Elsevier Saunders.
Questions?