Lower Extremity Blocks Flashcards
What are the indications for regional anesthesia? (5)
primary anesthetic PONV management History of MH or PONV Patient is too ill for general Physician surgeon preference
Absolute contraindications to regional anesthesia (4)
Patient Refusal
Infection at Site
Anticoagulant therapy with active bleeding
Proven allergy to local anesthetic
Relative contraindications to regional anesthesia (5)
uncooperative patient/neurological disease/psychiatric disease
an anesthetized patient
bleeding diathesis secondary to an anticoagulant or genetic disorder
Blood stream infection
pre-existing peripheral neuropathy
Complications of regional anesthesia (6_
intravascular injection/ LAST Intraneural injection High spinal (intra-thecal) vascular injury (hematoma) Infection
Benefits of Regional anesthesia (10)
Decreased PONV Decreased LOS Decreased opioid requirements decreased Post op pain Decreased surgical stress decreased blood loss Increased patient satisfaction Maintained upper airway and pharyngeal reflexes increased gastric mobility ability to titrate analgesia/ place catheter
Benefits of US vs. Landmark technique
Visualization improvement of block quality Lower doses of anesthesia less painful administration improved patient satisifaction safer?
What can you visualize better with US during a regional block?
anatomic structures
real-time needle movements
spread of LA
Pre-Procedure Checklist (8)
Verify correct patient Obtain consent Verify correct procedure Verify correct extremity Gather all necessary equipment Place patient on monitors/ supplemental O2/ EtCO2 monitor (if sedating) Obtain baseline VS and monitor throughout procedure Administer proper/adequate sedation
Supplies for Regional Anesthesia
US Machine Sterile Gloves Probe cover Drapes CHG Appropriate Needle with connection to nerve stimulator Peripheral Nerve Stimulator for Needle Device (sorry don't know what that is called) LA for block LA for skin wheal if warranted SW for hydrodissection decadron?
What compromises the lumbar plexus? (ventral rami and nerves)
L1-L4 Femoral Nerve Obturator Nerve Lateral femoral cutaneous Nerve Also- ilioiguinal nerve iliohypogastric nerve
What compromises the lumbar plexus? (ventral rami and nerves)
L4-5 through S1-5
Tibial nerve
peroneal nerve
nerves of ankle and foot
What are the blocks of the lumbar plexus?
femoral fascia iliaca adductor canal saphenous PENG
What are the blocks of the lumbosacral plexus
sciatic (subgluteal)
sciatic (popliteal)
IPACK
Ankle block
What does the lumbar plexus provide innervation too? What innervation?
sensory and motor innervation to thigh, anterolateral knee
sensory innervation to medial aspect of lower extremity below the knee
Where is the femoral nerve located?
Lateral to the artery
Deep to the fascia lata and fascia iliaca
Superior to the iliopsoas muscle
What is the target of the femoral nerve block?
major branches of lumbar plexus
femoral nerve
Where does the femoral nerve block provide anesthesia too?
anterior to thigh, knee, and medial aspect of lower leg
What muscle group does the femoral nerve innervate?
quadraceips
What are the indications for femoral nerve block?
surgery on the anterior aspect of the thigh
superficial surgery on medial aspect of leg below the knee
What are surgical examples that require a femoral block?
quadriceps tendon repair, long saphenous vein stripping, postoperative pain femur/ knee surgery
TKA
Can a catheter be placed in a femoral nerve block for anaglesia?
yes for major knee and femur surgery
Just be careful and remove ASAP because femur is a dirty site- high risk for infection
Relative contraindications for femoral nerve block
previous ilioinguinal surgery large inguinal lymph node/tumor infection peritoneal infection femoral neuropathy
Describe the anatomy of the femoral nerve
largest branch in the lumbar plexus
dorsal division of the anterior rami L2-L4
emerges from the lateral border of the psoas muscle and remains deep to the fasica iliaca
Anterior division innervates the sartorius and pectineus muscle
Describe Landmark Technique for Femoral Nerve Block
Patient is supine with leg slight external rotated
In the femoral crease, Find the femoral artery (we know the nerve is lateral to the artery)
Therefore, go 1 cm lateral to to the pulsating artery
Insert needle at a 45 degree angle towards head
Using nerve stimulator look for quadracieps/ patellar twitches. If still twitching at 0.3mA retract needle til twitches are absent.
Aspirate.
Small increments of LA injected
What is the surgical anesthesia LA choice for femoral nerve blocks?
mepivacaine or lidocaine 1.5-2%
Ropivacaine 0.5-0.75%
What is the postoperative anesthesia LA choice for femoral nerve blocks?
Ropivacaine or bupivacaine 0.2-0.25%
Discuss the USG technique for FNB?
Patient is supine with external rotation of extremity
Transducer is placed at inguinal crease
Identify femoral artery at level of femoral crease
If femoral artery and deep artery of thigh are both seen, scan proximal until fem artery seen
Femoral nerve is lateral to artery and covered by fascia iliaca and 2-4cm deep
Needle inserted lateral to medial
20ml local anesthetic
Goal for the LA to push the Femoral nerve lower can re-enter under nerve trying to get donut around it
Pearls of FNB (5)
Doppler needs to be utilized to check for absence or presence of vessels
If LA is placed below fascia iliaca and lateral to artery, successful blocks occur despite the lack of twitches
Watch your needle tip- can easily puncture vascular or inject local
Lymph nodes are not continuous, make sure to be scanning up and down to distinguish between lymph and nerves
No ambulation for 24 hours
Describe the anatomy of the fascia iliaca
Located anterior to the iliacus muscle
Deep to sartorius muscle and fascia lata
Superior to iliopsoas muscle
Indications for the Fascia iliaca Block
Hip Anterior thigh Knee Femur fracture Alternatives to the femoral block/ ie lumbar plexus block
What are the targets for the fascia iliaca block?
Femoral nerve
Obtrurator nerve
lateral femoral cutaneous
Where does the lateral femoral cutaneous nerve stem from? what does it innervate?
(sensory) L2 and L3
Where does the obutrator nerve stem from? What does it innervate?
L2-L4 roots
Innervates portion of distal and medial thigh
Where is the obturator nerve anatomically?
Cross iliacus muscle,
Deep to fascia to medial thigh
What surgery needs to have the obturator nerve blocked?
IMPORTANT TO BLOCK WITH THA (ACETABULAR COMPONENT)
What volume of LA is required for a FIB?
40mls to block all three nerves
What volume of LA is required for FNB?
20ml
What is the goal of the FIB?
inject LA under fascia in a large volume that will spread broadly to reach nerves
Want to spread LA cephalad to hit the higher nerve roots
What are major landmarks for FIB?
deep Circumferential iliac artery
USG technique for FIB
Patient is supine, transducer placed parasagittal orientation (head to toe) just medial to anterior spinal IS then moved few cm caudad to see pelvis. Needle is placed towards cephalad inplane. Landmark: is deep circumferical iliac artery. Needle is directed to underside of fascia while being on pelvis side. Unzippering inidcates successful block. Circumferical artery should be superior to LA, if artery deep, block will be too superifical and will not work.
What are the CKAs to FIB
none
What are relative CKA to FIB?
uncooperative patient/ surgeon
infection at site
What are complications of FIB?
block failure intraperitoneal injection(bowel perf) femoral nerve palsy quadriceps weakness infection (increased with catheter)
Describe the adductor canal anatomy/ Landmarks
Saphenous nerve is branch of femoral nerve
Medial side of knee and ankle
Saphenous nerve is below sartorius muscle, lateral to superficial femoral artery and femoral vein
Key: Mid-thigh with femoral artery in middle of sartorius muscle
Indications for an adductor canal nerve block
TKA
ACL reconstruction
Anterior knee surgery
If used with sciatic nerve block: analgesia below the knee
Contraindications of ACB
patient refusal
Infection at site
Allergy to LA
Anticoagulant therapy/coagulopathy
What is the triangle of the ACB
medial aspect of adductor longus, medial aspect of sartorius and the point of the femoral triangle
What does the ACB block?
Sensory nerve block with minimal motor involvement
Medial aspect of the leg
What is the target of the ACB block?
Saphenous nerve that has branched from femoral nerve
effective for pain relief
What is the risk of a ACB?
risk of falls secondary to quadriceps weakness
USG ACB Technique
Patient Supine with slight rotation of extremity
Stand on operative side (scan at mid-thigh)
Transducer placed mid to distal third of thigh, high frequency array transducer
Short axis image, in plane needle insertion
LA deposited in fascial plane separating sartorius and vastus medialis lateral to femoral vessels
Hydro-dissection
Inject incrementally up to 20ml LA
How much LA is needed for a ACB block?
20ml
Pearls of ACB (4)
Nerve branches may be located on both sides of superficial femoral artery, pre-procedure scan may be helpful
Myotoxicity can occur if LA deposited in muscle
If Vastus medialis blocked well, may provide greater innervation to the knee then thought
Ie better sensory block then anticipated
Medial Knee is twitched
Anatomy of the Saphenous Nerve (5)
Terminal branch of femoral nerve
Travels superficially in the distal thigh
Infrapatellar branches to knee joint
Sartorius muscle descends across anterior thigh and forms roof over adductor canal in lower half of thigh- trapezoid shape
Sides of triangle canal formed by vastus medialis laterally and adductor longus or magnus medially depending on how proximal/distal scan is
Describe the saphenous nerve
Saphenous nerve is small, round, hyperechoic structure anterior to the femoral artery at the depth of 2-3cm
What does the saphenous nerve innervate?
Sensory innervation to medial aspect of lower extremity below the knee
Saphenous Block is useful for
Can be used with other blocks for surgery of ankle/foot
Saphenous Block USG technique
Supine slightly external rotation of leg
Transducer is placed at distal thigh
High Frequency array transducer
Short-axis image, in plane technique
Saphenous nerve can be found between the sartorius muscle and vastus medialis muscle, anterolateral to the femoral artery and vein
LA deposited in fascial plane separating the adductor longus and vastus medialis below the sQ tissue
5-10mL
How much LA is utilized for saphenous nerve blocks
5-10ml LA
Does the quadriceps stay intact in a saphenous nerve block?
yes
Where is the direction of the needle going in a saphenous nerve block?
below the satorius muscle
What does the lumbosacral plexus supply innervation to?
sensory and motor innervation to posterior thigh, lower extremity below the knee
What does the sciatic nerve run deep to?
gluteous maximus between ischial tuberosity and greater trochanter
Where does the sciatic nerve stem from?
L4-L5 and then S1 to S2
What does the sciatic nerve supply innervation to?
Sensory and motor block of entire lower extremity below the knee (- medial lowe extremity below knee ie saphenous)
What does a sciatic nerve block miss?
Posterior Thigh is innervated by femoral cutaneous nerve, which may by missed with sciatic nerve block
Sciatic (Subgluteal) USG technique
- Patient can be prone or lateral
- Low frequency curvilinear transducer placed to distal gluteal crease
- Short axis, in plane needle insertion
- Place needle tip adjacent to sciatic nerve, between adductor magnus and biceps femoris
- LA deposited in fascial plane between gluteus maximum and adductor magnus muscles
Inject 20ml LA
How much LA is utilized in a sciatic nerve block (subgluteal)
20 ml
Where does the sciatic nerve spilt into the tibial and common peroneal nerve?
10cm above popliteal fossa
What is the sciatic nerve bordered by in the popliteal fossa?
superiorly and medially by semitendinosus and semimembranosus muscles and superiorly and laterally by biceps femoris muscle
Indications for a Popliteal Nerve Block (3)
Foot, ankle, achilles tendon surgery
CKA to the Popliteal nerve block
patient refusal, LA allergy, infection at site, coagulopathy with active bleeding
What will occur with the popliteal nerve block?
Foot drop
Describe USG Technique for Popliteal Nerve Block
Supine with operative leg elevated
High frequency transducer placed in popliteal crease
Tibial nerve is superior and proximal to vein and artery
Scan proximal to locate bifurcation with peroneal nerve
Short axis image distal to tibial and peroneal bifurcation
24g 4in B bevel needle inserted in the plane lateral to medial at lateral thigh
Circumferential spread around each nerve
Transducer may have to angles toward the foot to obtain a better image of nerve (anisotropy) because the nerve may be superficial
Circumferential spread around each nerve ensures a dense block
Complications of Popliteal nerve block
IV or intraneural injection
Easy to cause peroneal nerve injury as may not be seen on US
Peroneal nerve is prone to injury due to location
What four nerves are covered in a Popliteal nerve block?
posterior tibial nerve
deep peroneal nerve
superficial peroneal nerve
sural nerve
Goal of an IPACK Nerve Block/ What does it mean?
To place LA Infiltration between popliteal artery and posterior capsule of knee to block the terminal branches innervating knee joint, sparing distal innervation of tibial and peroneal branches
What is an IPACK nerve block an alternative too
Alterative to sciatic nerve block
What is the result of an IPACK block?
Provides analgesia following knee arthroplasty and facilitates ambulation
Indications for an IPACK block?
Posterior knee pain control for TKA
Describe the USG technique for a IPACK block?
Position: lateral decubitus position
Transducer placed in transverse plane above popliteal crease to visualize tibial nerve, common peroneal nerve, popliteal artery and femoral condyles
Transversely over medial aspect of knee 2-3cm above patella
Slide transducer to identify distal femoral shaft and popliteal artery
If femoral condyles is visualized, slide proximal until condyles disappear and femoral shaft is identified
Use color doppler
Identify space between popliteal artery and intercondylar notch
Needle inserted lateral to medial
In plane from antero-medial aspect of knee towards space between popliteal artery and femur
15-20ml injected slowly while withdrawing needle
Fills posterior capsule of knee with LA
How much LA is injected for a IPACK block?
15-20ml
What are the five nerves that supply innervation to the foot?
Sural Deep peroneal Nerve Superficial peroneal nerve Tibial nerve Saphenous nerve
Describe the tibial nerve innveration and stem
nerve roots at 4-5 lumbar roots along with 1-3 sacral roots
Larger of two branches is the sciatic nerve which lies on medial side of achilles tendon
Nerve is covered by flexor retinaculum
Sensory innervation of foot
Describe the Saphenous nerve innveration and stem
Terminal branch of femoral nerve and travels subcutaneously from the lateral side of the knee joint
Describe the sural nerve innveration and stem
Union of a branch of the tibial nerve and common peroneal nerve
Sensory innervation to the posterior portion of the sole of the foot and posterior portion of the heel and portion of achilles tendon immediately above ankle
Describe the Superficial peroneal nerve innveration and stem
Roots of 4 and 5th lumbar roots
1st and 2nd sacral nerve roots
Describe the deep peroneal nerve innveration and stem
Muscle of the great toe as transverses the leg and into ankle
Innervation to short extensors of the toes and provides sensory innervation to the skin on the lateral side of the hallux and on the medial side of the second digit
Nerve and artery cross each other, nerve lies laterally to the artery and medial to the long extensor muscle of the great toe and ankle
Indications for ankle blocks
surgical anesthesia and postoperative analgesia for surgery of the foot
What patients are appropriate for ankle blocks
Good for patients with gangrene of the foot or those with diabetes who have foot ulcers
How much LA is used at each nerve for ankle blocks?
3-5ml
What are the two deep nerves of the ankle?
tibial nerve and deep peroneal
What are the three superficial nerves of the ankle?
superficial peroneal nerve, sural nerve and saphenous nerve
Complications of ankle blocks (6)
LAST Paresthesia (should be temporary) Nerve injury Bleeding Infection Intravascular puncture/injection
