Lower Extremity Blocks

Question 1

Regional Anesthesia Reduces

Answer 1

• Surgical stress
• Opioid consumption
• SNS stimulation

Primarily associated w/ spinals & epidurals - overall blood loss & DVT risk

Question 2

Regional Anesthesia Benefits

Answer 2

Provide anesthesia and/or analgesia (titratable)
- Able to re-dose w/ catheter
- Convert from pain management to 1° anesthetic
VERSATILE
- Control sensory & motor blockade extent
- Used w/ or w/o adjunct medications

Question 3

Block Supplies

Answer 3

• Sterile gloves
• Sterile transducer cover
• Antimicrobial CHG
• Nerve stimulation
• Block needle
• Local anesthetic
• Additive (Epi or Decadron)
• SQ local anesthetic
• 4x4s gauze

Question 4

Local Anesthetic Type & Amount

Answer 4

20-40mL per block
Depends on 
- Patient factors
- Time/length
- Procedure
- Block purpose 1° anesthetic vs. adjunct

Question 5

Lumbar Plexus

Answer 5

Lower extremity innervation - supplies sensory innervation to thigh, anterolateral knee, and sensory innervation to medial aspect lower extremity below the knee
Nerve roots L1-4 (occasionally T12)
- Ilioinguinal & iliohypogastric nerves
- Lateral femoral cutaneous, femoral (saphenous), & obturator nerves

Question 6

Lumbar Plexus Blocks

Answer 6

Femoral
Fascia iliaca
Adductor canal
Saphenous (thigh & ankle)

Question 7

Lumbosacral Plexus

Answer 7

Lower extremity innervation - supplies sensory & motor innervation to posterior thigh, knee, & lower extremity below the knee w/ exception to sensory innervation provided by saphenous nerve
Nerve roots L4-5 & S1-3
- Sciatic nerve (tibial, peroneal, & nerves ankle/foot)

Question 8

Lumbosacral Plexus Blocks

Answer 8

Sciatic - subgluteal & popliteal
iPACK
Ankle blocks

Question 9

Femoral Nerve Block FNB

Answer 9

Targets major lumbar plexus branch
Provides analgesia to anterior thigh, knee, and medial aspect lower leg
Lateral → medial
Femoral nerve → artery → vein
- Deep to fascia lata & iliaca
- Superior to the iliopsoas muscle
Limits ambulation d/t quadriceps weakness

Question 10

Fascia Iliaca Block FIB

Answer 10

Lumbar plexus block
Target femoral, obturator, & lateral femoral cutaneous nerves
Increased volume 40mL required to block all three
Goal lateral & medial spread
Limits ambulation d/t quadriceps weakness

Question 11

Adductor Canal Block ACB

Answer 11

Lumbar plexus block
TKA multi-modal pain management ERAS protocols
↓LOS & opioid administration
Intermuscular tunnel in anteromedial thigh posterior to the sartorius muscle
Saphenous nerve (sensory only) & vastus medialis pass through the canal
Less significant motor blockade (quadriceps weakness)

Question 12

Adductor Canal Muscles

Answer 12

Sartorius = roof
Adductor longus = medial
Vastus medialis = lateral

Canal ends at adductor hiatus (femoral triangle apex)

Question 13

Saphenous Nerve

Answer 13

Femoral nerve terminal branch
Distal to adductor canal saphenous lies superficial in the distal thigh
Provides only sensory information to medial aspect lower extremity below the knee

Question 14

Saphenous Nerve Block (Thigh)

Answer 14

Lumbar plexus block

Used in conjunction w/ other blocks for surgical procedures involving the ankle & foot

Question 15

Sciatic Nerve

Answer 15

Runs deep to the gluteus maximus b/w ischial tuberosity & greater trochanter

Question 16

Sciatic Block (Subgluteal)

Answer 16

Results in sensory & motor blockade entire lower extremity below the knee except for sensory innervation to medial lower extremity provided by saphenous nerve
Posterior thigh innervated by femorocutaneous nerve missed w/ subgluteal approach
Insert needle perpendicular

Question 17

Popliteal Nerve Block

Answer 17

Target sciatic nerve above the knee
Sciatic nerve branches into tibial & common peroneal nerves
Superior/medial border semi-tendinosus & semi-membranosus
Superior/lateral biceps femoris muscle
Lateral → medial
Peroneal (fibular) → tibial nerve → popliteal artery

Question 18

Tibial Nerve

Answer 18

Branches off sciatic nerve

Medial & larger

Question 19

Peroneal Nerve

Answer 19

Branches off sciatic nerve

Lateral & smaller

Question 20

iPACK

Answer 20

Infiltration b/w popliteal artery & posterior knee capsule to block terminal branches innervating the joint
Spares distal tibial & peroneal branch innervation to reduce foot drop & facilitate postop ambulation
Posterior knee pain control TKA

Question 21

Nerve Innervation to the Foot

Answer 21

Tibial 
Deep peroneal
Superficial peroneal
Saphenous - medial
Sural - lateral

Question 22

Lower Extremity Block Complications

Answer 22

LAST
Paresthesia or nerve injury (direct trauma or LA reaction)
Bleeding or infection
Intravascular puncture/injection