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c. regional exam 3 (w13) > lower extremity blocks 3/11 > Flashcards

lower extremity blocks 3/11 Flashcards

1
Q

LUMBAR PLEXUS:

  1. where do the nerves exit in respect to the vertebra?
  2. what levels of rami does it inculde and does lumbar plexus come from anterior or posterior rami?
  3. what muscle is the lumbar plexus formed in?
A
  1. exit cauddad (below) to their numbered vertebra
  2. Anterior ventral rami L1-L4 (occasional T12-L5)–(posterior rami L1-L5 supply muscles of skin of back)
  3. formed in body of psoas major muscle
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2
Q

SACRAL PLEXUS:

what rami does it originate from?

A

rami of L4-S3

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3
Q
  1. the lumbar plexus innervates what part of the lower extremity?
  2. the lumbosacral plexus innervates what part of the LE?
A
  1. lumbar plexus: ventral part of LE

2. lumbosacral plexus: dorsal part of LE

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4
Q

Lower Extremity Blocks• Advantages:

8 things

A

1– Avoid sympathectomy associated with spinal
2– Avoid general anesthesia in high risk patients
3– Little effect on hemodynamic status
4– Appropriate for patients with head injury, CV instability, localized infection (spine)
5– Early ambulation
6– Perioperative and postoperative pain relief – Reduced nausea and vomiting
7– Continuous infusion catheter

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5
Q

Lower Extremity Blocks• Disadvantages:

5 things

A

1– Time consuming
2– Failure (up to 5% in the best hands)
3– Mobilization of patient to position for block may be difficult due to co-morbidities (obesity, arthritis, fractures)
4– Nerves not as compact compared to brachial plexus
5– Many providers not as comfortable with techniques due to ease of blocking lower extremities with neuraxial techniques

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6
Q

Lower Extremity Blocks

  1. Patient Preparation: what should be done prior to deciding which block?
  2. how are LE blocks used in surgery?
  3. how are they used post op?
A

1• Complete preoperative Assessment including:
– Thorough neurologic exam
– Patient Education
2• May be used as only anesthetic or combined with GA or MAC
3• Post-op pain management (+- catheter

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7
Q

Lower Extremity Blocks Patient Preparation
1• Contraindications: (6 things)
2• what should be monitored?

A 
Lower Extremity Blocks Patient Preparation
1. contraindications
	a. Patient Refusal, 
	b. uncooperative patient, 
	c. block interfering with procedure, 
	d. coagulopathy, 
	e. infection at site, 
	f.  neurologic disease
2• Monitoring is the same as any other anesthetic during block and intraoperatively
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8
Q
  1. what 2 plexuses make up the lower ext. nerve supply?

2. what is the nerve span for the lower extremities (from where to where)?

A

1• Nerve supply to lower extremity is from 2 plexuses: lumbar plexus and sacral plexus (also referred to as lumbosacral plexus)
2• L1-S3

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9
Q 
Lumbar Plexus (Cephalad Branches):
there are 3 of them:
A

Lumbar Plexus (Cephalad Branches):
– Iliohypogastric Nerve- L1
– Ilioinguinal Nerve- L1
– Gentiofemoral Nerve- L1-L2

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10
Q

Lumbar Plexus (Caudal Branches)

  1. name the 3 branches:
  2. why are these branches important to us?
A
  1. Lumbar Plexus (Caudal Branches):
    – Lateral Femoral Cutaneous Nerve (LFC)- L2-L3
    – Femoral Nerve- L2-L4
    – Obturator Nerve- L2-L4
  2. These are the branches we are concerned with for lower extremity blocks!
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11
Q
  1. what are the 2 divisions of the lumbar plexus?

2. how many peripheral branches of these 2 divisions?

A
  1. lumbar plexus:
    a) cephalad branches
    b) caudal branches
  2. 6 branches
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12
Q
  1. track the path and innervations of the Lateral Femoral Cutaneous (L2-L3):
  2. what type of innervation is this nerve?
A
  1. path of lateral femoral cutaneous
    – Emerges medial to ASIS
    – Passes under lateral end of inguinal ligament
    – Superficial or deep to Sartorius muscle
    – Descends deep to fascia lata
  2. Purely SENSORY innervation to lateral thigh (cutaneous).
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13
Q

what area does lateral femoral cutaneous (LFC) supply sensory to?

A

LFC- Purely sensory nerve supplies lateral buttock distal to greater trochanter and proximal two thirds of lateral thigh.

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14
Q
  1. track the path of the Femoral Nerve (L2-L4):

2. what areas of does it innervate?

A

Femoral Nerve
1. – Emerges through psoas muscle and
descends in groove between psoas and iliacus muscles
– Passes under inguinal ligament lateral to femoral artery
– Splits into numerous branches upon entering femoral triangle
2.– Supplies muscle and skin of anterior thigh, knee, hips

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15
Q
  1. what makes up the femoral triangle?

2. what is the order of artery, nerve and vein from medial to lateral?

A 
femoral triangle
1. 	inguinal ligament (superiorly), 
	sartorious (laterally) 
	adductor longus (medially)
2. 'V' 'A' 'N'- vein-artery-nerve from medial to lateral
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16
Q
  1. femoral nerve innervates what?

2. femoral nerve is the ____ terminal nerve of lumbar plexus?

A
  1. Femoral Nerve covers skin of anterior thigh, knee, hips .
  2. Largest terminal branch of lumbar plexus.
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17
Q

Obturator Nerve (L2-L4)

  1. track its descent:
  2. what does it innervate?
A

Obturator Nerve
1. – Descends towards pelvis on medial boarder of psoas muscle
– Exits pelvis through obturator foramen
2.– Innervates adductor muscles of thigh, hip, knee joints, & skin medial to thigh

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18
Q

Sacral Plexus:

  1. what rami make up sacral plexus?
  2. what 2 major nerves originate from the sacral plexus?
  3. what does the sacral plexus give innervation to?
A

Sacral Plexus:
1– Anterior rami of L4-L5 & S1-S3 (some sources S4)
2– Two major nerves:
• Sciatic (L4-S3)
• Posterior cutaneous nerve of thigh (S1-S3)
3– innervation of sacral plexus is:
– Sensory and motor to posterior and lateral part of leg
– Nearly entire innervation of foot

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19
Q

Posterior cutaneous nerve (S1-S3)

  • what plexus does it originate from?
  • what other nerve does it course with?
  • where structure does it exit thru?
A

Posterior cutaneous nerve
– From sacral plexus
– Courses with sciatic nerve through pelvis
– Exits via greater sciatic foramen

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20
Q

Posterior cutaneous nerve (S1- S3)

• Supplies skin of…

A

Posterior cutaneous nerve:

buttock and proximal posterior thigh

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21
Q

Sciatic Nerve (L4-S3):

  1. origin
  2. why is it special?
  3. passes thru and lies on what?
  4. descends to where?
A 
Sciatic Nerve:
– From sacral plexus 
– Largest nerve in body
– Passes out of pelvis through greater sciatic foramen and lies on sciatic notch
– Descends along medial aspect of femur
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22
Q

• Sciatic Nerve cont…

-what does it innervate?

A

Sciatic Nerve:

– Motor and sensory innervtion to posterior thigh and majority of lower leg (except medial lower leg)

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23
Q

Sciatic Nerve (L4-S3)

  1. where is it closer to the skin? where does it run
  2. what does it divide into? which one is medial? which is lateral?
A 
Sciatic Nerve:
1– Becomes superficial at lower boarder of gluteus maximus and travels to popliteal fossa
2– Divides into:
	•  Tibial Nerve (medial)
	•  Common Peroneal Nerve (lateral)
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24
Q

Tibial Nerve:

  1. where does it run?
  2. what are the sensory and motor innervations?
A 
Tibial Nerve:
1--Travels down posterior calf
	– Passes under medial malleolus
2– sensory: Supplies skin of medial and plantar foot
	motor: Plantar flexion
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25
Q

what nerves innervate the foot?

  1. what is the main nerve that services most of the foot?
  2. what are the branches of this nerve?
  3. what about the other aspects of the foot (arch and outer heel)
A

nerves that innervate the foot:

  1. tibial nerve
  2. most of foot:
    • medial calcaneal branches-(S1,2) heel
    • medial plantar nerve-(L4-5) 2/3 of the foot (from the medial side) out to1/2 the 4th toe
    • lateral plantar nerve- (S1,2) lateral 1/3 of foot
  3. rest of foot:
    a) outer heel: sural nerve (s1,2)-via lateral calcaeal and lateral dorsal cutaneous nerve
    b) arch: saphenous nerve (L3,4)
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26
Q

Common Peroneal Nerve

  • courses where?
  • divides into what branches?
A 
Common Peroneal Nerve:
– Courses around head of fibula (lateraly)
– Divides into:
	•  Superficial Peroneal Nerve
	•  Deep Peroneal Nerve
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27
Q

2 branches of the common peroneal nerve:

trace the branches

A 
2 branches of the common peroneal nerve:
1. Superficial Peroneal Nerve
	– Sensory nerve
	– Supplies anterior foot
 2. Deep Peroneal Nerve
	– Motor innervation: dorsiflexion of foot
	– Sensory innervation: space between 1st & 2nd 
toe
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28
Q

Deep Peroneal Nerve: where does it enter the foot?

A

Deep Peroneal Nerve:

-Enters foot lateral to anterior tibial artery between anterior tibialis tendon & extensor hallicus longus tendon

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29
Q

Superficial Peroneal Nerve:

-how does it course?

A

Superficial Peroneal Nerve:

-passes down the lateral calf and divides into terminal branches medial to lateral maleolus

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30
Q

Sural Nerve:

  1. what type of nerve?
  2. what forms this nerve?
  3. what does the nerve pass under?
  4. what does it supply?
A

Sural Nerve:

  1. Sensory nerve
  2. Formed from branches of common peroneal and tibial nerves
  3. Passes under lateral malleolus
  4. Supplies lateral foot
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31
Q
  1. what is a lower concentration block for Local Anesthetic?
  2. what kind of block does it give you?
  3. what kind of block does a high concentration block give you?
A
  1. 10-15 ml of local (0.5%-0.75% mepiv or lido; .25% bupiv; 0.2% ropiv)
  2. sensory, no motor
  3. sensory with some motor
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32
Q

what equipment will you need for a lower extremity block?

A 
equipment for block:
•  Standard monitors
•  Emergency drugs
•  Suction
•  Airway equipment
•  O2
•  Sedation
•  PNS
•  Marking Pen
•  Ruler
•  2-4 inch insulated needle and 22 G, 10-15 cm spinal needle and B-bevel needle
•  Local anesthetic
•  Alcohol pads & chloraprep
•  Sterile gloves
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33
Q
  1. How to choose your LA:
  2. what does onset and duration depend on?
  3. what LAs can be mixed? What problem does that cause?
A
  1. Choice of LA
    – Duration of procedure
    – Time until start of procedure
    – Degree of anticipated pain
    – Toxicity of agent
    – Ambulatory vs. in-patient surgery
    2• Onset and duration different depending on site.
    – Example:
    • 0.5% ropivicaine for BP block = 10-12 hr of analgesia
    • 0.5% ropivicaine for sciatic nerve block = up to 24 hr of analgesia
    • This difference is likely due to difference in vascularity
    3• Mixing of LA
    – Lidocaine + Bupivicaine = faster onset and longer DOA
    • Problem is onset, duration and potency become more unpredictable
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34
Q
  1. what does adding bicarb do to LA?

2. what does adding epi do?

A
  1. Adding sodium bicarbonate to LA
    – Increases pH of LA, increases amount of LA in uncharged base form, increasing rate of diffusion across nerve membrane, speeding onset of action
  2. Adding epinephrine to LA
    – Delays vascular absorption, increasing duration of drug contact with nerve issues, increasing duration of action
    – Marker of intravenous injection
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35
Q

Techniques: Lumbar Plexus Blocks
I. block #1
II. block #2

A

• Lumbar plexus blocks:
I. you can do one block that BLOCKS EVERYTHING
1. Lumbar plexus block (consistently blocks
LFC, femoral, obturator nerves)

II. Or you may block the individual nerves of the plexus:

1. Lateral Femoral Cutaneous Nerve (LFC)- L2-L3
2. Femoral Nerve- L2-L4 
3. Obturator Nerve- L2-L4
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36
Q

how to do a LFC nerve block:
1. what size needle? in what location?
2. what tissue will you feel a pop going thru?
3. how much LA is injected and in what manner?
4.

A

LFC nerve block:
Needle (22 G 2 inch insulated) inserted 2 cm caudal and medial to the anterior superior iliac spine
– Advance deep into fascia lata
– Will feel “pop” as fascial layer (fascia lata) is penetrated
– 10-15 ml LA in fanwise manner above and below the fascia lata, from medial to lateral

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37
Q

Lateral Femoral Cutaneous (LFC) Nerve Block

  1. Uses:
  2. how does the nerve Course?
  3. what type of innervation?
A

Lateral Femoral Cutaneous (LFC) Nerve Block:
1. uses:
• Anesthetizing lateral aspect of thigh
• Small skin gran donor site
• Lessens complaints of tourniquet pain
2 Course:
• Emerges from lateral boarder of psoas muscle, courses inferiorly and laterally towards ASIS, passes under inguinal ligament
3. innervation:
• Only sensory innervation

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38
Q

dose for LFC block:

  1. what type of concentration is good for LFC block? how many mL?
  2. examples of LAs and doses:
A 
dose for LFC block:
1. Low concentration of 10-15 ml of local anesthetic is effective because no motor components
2. Examples:
	– 0.5%-0.75% Mepivacaine or Lidocaine 
	– 0.25% Bupivacaine
	– 0.2% Ropivacaine
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39
Q

LFC nerve block Techniques:

  1. how should you position patient?
  2. what is the landmark?
A

LFC nerve block Techniques:
– Supine position
– Palpate anterior superior iliac spine

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40
Q

ultrasound technique for LFC nerve block:

  1. how to position leg?
  2. what do you mark?
  3. where do you place transducer and how do you scan?
  4. how does LFCN appear?
A

ultrasound technique for LFC nerve block:
1. Supine, leg extended, neutral position
2• Mark ASIS (anterior superior iliac spine) and IL (inguinal ligament) Prep skin and transducer
3• Place transducer medial to ASIS along IL, scan medially and inferiorly
4• LFCN is hyperechoic (BRIGHTER)

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41
Q 
what do structures do these stand for?
FL
FI
SAR
IL
A

• =Fascia lata
• = Fascia iliaca
• = Sartoriustorious (the LFCN passes over this muscle)
- = Inguinal Ligament

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42
Q
  1. uses for femoral nerve block?
  2. often combined with what othe blocks?
  3. how does the nerve course?
A
  1. uses for femoral nerve block:
    • Operations on anterior portion of thigh
    • Analgesia for femoral fracture
    • Post-op analgesia for knee surgery (+/-continuous catheter placement)
    2• Often combined with other LE Femoral Nerve PNBs (lateral femoral cutaneous, sciatic and obturator nerve block) to provide anesthesia for procedures of lower leg and foot
    3• Course:
    • Lies in groove between psoas major and iliac muscles, enters thigh deep to inguinal ligament
    • LATERAL TO FEMORAL ARTERY
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43
Q

femoral nerve block:

  1. at Inguinal Ligament, where does femoral nerve lie in proximity to femoral artery?
  2. where does it lie in proximity to 2 fascia (name them); is it in a vascular sheath? what nerve does it give rise to?
  3. where does it provide innervation? what type?
A

femoral nerve block:
1. At IL, femoral nerve lies lateral to femoral artery (VAN= medial to lateral)
2. lies in…
• Not in vascular sheath
• Lies deep to fascial lata & iliac fascia
• Distally gives rise to saphenous nerve
3. provides cutaneous innervation to medial calf

44
Q

Femoral Nerve Block: Pharmacologic Choice

  1. Motor block: what concentrations?
  2. Sensory block: what concentrations?
  3. how much fluid should be injected?
  4. what changes the volume you inject with each block?
  5. what should you always do before giving LAs?
A 
femoral nerve block conc:
1•  = higher concentrations 
2•  = lower concentrations 
3•  = Inject 20-40 ml of LA
4.  Volume often dependant on if other blocks are being performed as well
5. always calculate toxic doses!
45
Q

femoral block:

  1. what position should patient be in?
  2. what are the landmarks? what does the line run with?
  3. what runs thru the center line?
  4. what do you palpate for?
  5. which direction will you go from there?
A

femoral block:
1• Supine
2• Palpate ASIS and pubic symphysis. Draw line (inguinal ligament)
3• Femoral nerve passes through center of line
4• Palpate femoral artery
5. laterally (v>a>n&raquo_space;laterally); Needle (22 G, 2 inch insulated) inserted perpendicular 1 cm lateral to femoral artery and 1 cm caudal to inguinal ligament (or just adjacent to artery)

46
Q

femoral block cont.

  1. what will be heard/felt? what causes this?
  2. what will the nerve stimulator cause? at what mA?
  3. what may or may not be elicited?
  4. is nerve deep or superficial? what depth?
  5. how much is delivered and in what manner?
  6. why is fanning done? if you do only one position which should it be?
A

femoral block cont.
1• Pop with penetration of fascia lata & iliac fascia
2• Nerve stimulator= contraction of quadriceps (or patellar snap) muscle at 3 cm deep)
5• Deliver 20-40 ml LA to block femoral nerve in a fan like manner from needle position 1 to 2 (15 degrees apart)
6- Fanning due to possibility of nerve dividing into multiple branches (Some providers simply inject in location 1 and have positive results)

47
Q

femoral nerve block:
Needle (__G, 2 __ insulated) inserted perpendicular __ cm lateral to ____ _____ and __ cm caudal to ____ _____ (or just adjacent to artery)

A

femoral nerve block:
Needle (22 G, 2 inch insulated) inserted perpendicular 1 cm lateral to femoral artery and 1 cm caudal to inguinal ligament (or just adjacent to artery)

49
Q

ultrasound guided FN block (continued…)

  1. step 4 is to …?
  2. indentify what vessels?
  3. identify what muscle?
  4. on ultrasound FN is hyperechoic or hypoechoic?
  5. what shape region is it found; Is it deep or superficial to ___ muscle?
  6. what is the name of the hyperechoic line superficial to the femoral nerve?
  7. lymph nodes look (hypo or hyper echoic)? in which direction should you scan? why?
A

ultrasound guided FN block (continued…)
1—Survey…
2• Identify FA and FV
3• Identify iliopsoas muscle
4• FN is hyperechoic (remember- highly reflective and brighter than surrounding structures)
5• Often in triangular hyperechoic region, superficial to iliopsoas
6• Fascial lata (hyperechoic line) superficial to FN
7• Lymph nodes are also hyperechoic in this region… scan proximal and distal because the FN is continuous

49
Q

US guided femoral nerve block:

  1. position patient…?
  2. leg position…?
  3. mark what area?
  4. prep what?
A 
US guided femoral nerve block:
1-  Supine
2•  Leg neutral
3•  Expose groin, mark inguinal crease
4•  Skin and transducer prep
50
Q

Femoral Nerve Block Complications:

  1. name 4
  2. how often?
A 
Femoral Nerve Block Complications:
1. four complications	
	•  Failure
	•  Hematoma
	•  Dysesthesia 
	•  Intravascular injection
2. complications are rare
51
Q
  1. why is the obturator nerve difficult to block?

2. what does it innervete?

A
  1. it ascends on the medial border of the psoas and exits via the obturator foramen
  2. services inner leg/knee
52
Q

Obturator Nerve Block
1. what type of innervation?
2. to what part of leg?
#3-6. what is it used for?

A

Obturator Nerve Block:
1• Mixed sensory and motor nerve
2• Sensory innervation to medial thigh & knee
3• Decreases opioid requirements aner knee replacement when combined with femoral and sciatic blocks
4• Treat hip joint pain
5• Relief of adductor muscle spasm associated with hemi-or
paraplegia
6• Improve tourniquet tolerance

53
Q

Obturator Nerve Block: Pharmacologic Choice

  1. how does need for motor blockade determine dose?
  2. examples of LA dosesz;
A 
Obturator Nerve Block:
1•  Motor blockade often not necessary, therefore lower concentrations adequate
2•  Examples:
– 0.75-1.0% Lidocaine 
– 0.75-1.0% Mepivacaine 
– 0.25% Bupivacaine 
– 0.2% Ropivacaine
54
Q

Obturator Nerve path:

A

Obturator Nerve path: Courses:
• Descends towards the pelvis from medial border of psoas muscle
• Passes through obturator foramen
• Enters medial thigh, divides into anterior & posterior branch (to knee joint)

55
Q

Obturator Nerve Block: steps:

  • patient position?
  • what is the landmark?
  • mark __cm___&__cm___(should be___to femoral artery)?
  • what size needle
  • what will you hit when you insert needle? what should you do?
  • how far do you advence the needle?
  • how much LA is needed for this?
  • what will nerve stimulation cause?
A

Obturator Nerve Block: steps:
• Supine position
• Identify pubic tubercle
• Mark 1.5 cm lateral and 1.5 cm caudal (this point should lie medial to femoral artery)
• Insert a needle (22 G, 2 or 4 inch insulated needle)perpendicular to skin
• Advance until bone contacted (inferior ramus of pubis)
• Withdrawal needle slightly
• Redirect laterally & caudad to enter obturator foramen
• Advance 2-3 cm
• Inject 5 ml LA as needle is withdrawn to level of obturator foramen
• Reinsert needle more laterally
• Repeat process
• Inject a total of 10-20 ml of LA
• Nerve stimulator technique – Adduction of thigh

56
Q

Obturator Nerve Block Ultrasound

  • patient position?
  • leg position?
  • where is transducer placed?
  • what is scan depth setting?
  • what is the first landmark you are looking for?
  • there are 2 branches, each sandwiched between muscles:
    • anterior branch is between what muscles?
    • posterior branch is between what muscles?
  • nerve stimulation causes what?
A

Obturator Nerve Block Ultrasound
• Supine
• Leg rotated externally
• Expose groin & medial thigh
• Skin & transducer prep
• Place transducer in inguinal crease & scan distally (depth 2-4 cm)
• Find femoral vein below inguinal crease, move medially
• Anterior branch (hyperechoic) between adductor longus muscle & brevis
• Posterior branch (hyperechoic) between adductor brevis and magus
• Nerve stimulator– Adduction thigh muscle

57
Q

Obturator Nerve Block Complications

A 
Obturator Nerve Block Complications
•  Failure
•  Intravascular injection 
•  Hematoma
•  Nerve damage
•  (complications are rare)
58
Q

Lumbar Plexus

  • originates where (can also include what)?
  • has how many peripheral nerves?
  • what muscle does it form in?
  • to block it completely, it is best done (anteriorly or posteriorly)?
  • what nerves does a lumbar plexus block consistantly block?
A

Lumbar Plexus
• LP from ventral rami of L1-L4 (variable L5 &T12)
• LP has 6 peripheral nerves
• LP forms in body of psoas muscle
• Complete LP block usually blocked posteriorly
• Consistently blocks femoral, LFCN, obturator nerves

59
Q

what forms the lumbar plexus?

A

Lumbar plexus formed by ventral rami of L1-L4. Occasionally T12

60
Q

Lumbar Plexus Block: How to do one: (14 steps)

  • position of patient?
  • what is the landmark?
  • draw line to what spinous process?
  • identify what landmark next? do what next?
  • how many cm from center mark will that be?
  • set nerve stim to what and watch for what?
  • what will you hit (what is it), what do you do?
  • set nerve stim to what? how deepu will you go with the needle?
  • inject how much LA (total)?
A

Lumbar Plexus Block: How to do one: (14 steps)
1• Lateral decubitus position with operative side up
2• Identify iliac crest
3• Draw line to midline (usually L4 spinous process)
4• Next identify the posterior superior iliac spine
5• Draw a line from PSIS parallel to spine
6• Parallel line are normally 5 cm from each other
7• Set nerve stimulator to 1.0, will be watching for quadriceps muscle twitch
8• Insert needle with slight medial angle
9• Stop when bone reached (L4 transverse process)
10• Bring needle back towards skin
11• Walk off process caudally
12• Watch for nerve stimulation less than 2 cm caudal to spinous process
13• Twitch at 0.5 mA (usually around 5-8 cm)
14• LA injection 30-40 ml

61
Q

Lumbar Plexus Block

?? Ultrasound ?? can it be used?

A

Lumbar Plexus Block
• Ultrasound may be used…however the depth of this block makes visualization very difficult
• May use ultrasound to confirm boney anatomical landmarks-

62
Q

Lumbar Plexus Block complications:

A

Lumbar Plexus Block• Complications
– Intrathecal injection
– Epidural injection or diffusion (most common)
– Intravascular injection
– Retroperitoneal bleeding (controversial block for THIS very reason)

63
Q

Sciatic Nerve (Block)

  1. where does sciatic nerve originate?
  2. what is sciatic nerves grand distinction?
  3. how many nerve branches originate from sciatic?
A 
1•  Sciatic Nerve from lumbosacral plexus (L4-S3)
2•  Largest nerve in body
3•  Contains 2 major nerve branches:
	– Tibial
	– Common Peroneal
64
Q
  1. how does sciatic nerve exit pelvis (via what foramen)?
  2. near (in what proximity) to what muscle?
  3. travels under what muscle?
  4. continues ___toward thigh between what two bony structures?
  5. divides into what 2 nerve branches (what direction) to what fossa?
A

1• Sciatic nerve leaves pelvis via greater sciatic foramen
2• deep to piriformis muscle
3• Travels under gluteus maximus
4• Continues distally toward thigh between greater trochanter and ischial tuberosity
5• Divides into tibial and common peroneal nerves cephalad to popliteal fossa

65
Q

sciatic nerve innervation:

  • -motor:
  • -sensory:
A

sciatic nerve innervation:
–Motor to posterior thigh and all muscles of leg and foot.
–Sensory to skin of most of leg and foot
(medically speaking Leg=knee down to foot i.e. calf)

66
Q

Sciatic Nerve Block:

• Uses:

A

Sciatic Nerve Block:• Uses:
– Leg surgery with femoral nerve block
– Relief from sciatica
– Knee surgery with femoral, LFC, and obturator nerve block
– Foot and angle surgery with saphenous nerve (femoral) block

67
Q

Sciatic Nerve Block: Pharmacologic Choice

A

Sciatic Nerve Block: Pharmacologic Choice
• Motor block=higher concentration
– 1.5% Mepivacaine
– 1.5% Lidocaine
– 0.5% Bupivacaine
– 0.5-0.75% Ropivacaine
• 20-40 ml LA (calculate toxic dose if combining with other blocks)

68
Q 
Sciatic Nerve Block:
Classic Approach-
-where is the nerve blocked at (what structure)?
-what muscle is the landmark?
-what is the position called?
-what is the upper heel level with?
A
  • Block at greater sciatic notch (see next slide)
  • Piriform muscle is the landmark
  • Lateral SIMS position (blocked side up)
  • Upper knee flexed so heel at about knee level of down leg
69
Q

Sciatic Nerve Block: Classic Approach

  • what are first 2 the landmarks?
  • draw a line between what 2 landmarks (not the original 2)
  • draw a second line between one of the first 2 landmarks and another new landmark; what are they?
  • draw anothe line from what to what?
  • advance toward what bone/landmark?
  • what size needle? advence how deep or until what is elicited?
  • nerve stimulator at less than ___ will elicit what foot reactions?
  • how much LA total?
A

Sciatic Nerve Block: Classic Approach
1• Landmarks
–a.Greater trochanter
–b.Posterior superior iliac spine
– Draw a line connecting which is approximately the superior boarder of the piriform muscle and upper boarder of sciatic notch
• Draw a second line from greater trochanter to sacral hiatus
• Draw a line from midpoint of first line to intersect the second line
• Insert needle directed towards pubic symphysis (perpendicular to skin)
• 22 G, 4 inch insulated needle
• Advance 6-10 cm or until paresthesia is reported in sciatic nerve distribution or nerve stimulation
– Proper placement: plantar flexion (desirable), dorsiflexion, eversion at <0.5 mA
• If periosteum is contacted redirect medially or laterally
• Aspirate, inject 20-40 cc LA

70
Q

Sciatic Nerve Block

what movements verify successful needle placement for sciatic nerve?

A

Sciatic Nerve Block:

  1. ankle joing movement:
    a. dorsiflexion
    b. plantar flexion
    c. eversion of foot
71
Q 
Sciatic Nerve Block:
Anterior Approach
1. why must you sedate the patient prior to this block?
2. how to perform:
	-position of patient and leg?
	-identify what landmarks?
	-draw 1st line over what landmark?
	-draw 2nd
A

Sciatic Nerve Block:
1. • Nerve is deep- painful, sedation is appropriate
2• Supine posision, leg neutral
• Identify anterior superior iliac spine and pubic tubercle
• Draw 1st line, over inguinal ligament
• Divide into 3 parts
• Draw a 2nd perpendicular line distally from junction of the medial and middle thirds
• Draw a 3rd line parallel to the 1st from the cephalad portion of the greater trochanter to the 2nd line
• 2nd and 3rd line intersection is insertion point
• Insert needle perpendicular to planes
• Once periosteum is contacted, withdrawal needle and redirect medial.
• Inject 20-40 ml LA aner paresthesia or nerve stimulator response
– plantar flexion/inversion or dorsiflexion/ eversion at < 0.5 mA

72
Q 
How to perform a Sciatic Nerve Block Ultrasound
1. what region is it done?
2. how is the patient positioned?
3. what are landmarks?
4-8. finish the steps:
A

How to perform a Sciatic Nerve Block Ultrasound:
1• Gluteal Region
2• Semi-prone (Sims) position, operative side upright, hip and knee flexed
3• See classic approach for landmarks
(steps 4-8)
• Skin an transducer prep
• Scan…Sciatic nerve is hyperechoic (bright)
• Depth > 4 cm
• IdenFfy ischial bone
• Locate gluteus maximus muscle (superficial and posterior to SN
• Insert needle on lateral end of US probe
• Confirm needle placement by electrical stimulation
• Inject 20-40 ml LA

73
Q

why is a sciatic nerve block good

A

why is a sciatic nerve block good:

it lasts a very long time d/t fact there is very little vascularity in that area.

74
Q

Sciatitic Nerve Block Complications

A
  • Sympathetic block
  • Hematoma (rare)
  • Intraneural injection
  • Residual paresthesia-resolves
  • Failure
  • Intravascular injection
75
Q

sciatic nerve block complications

  1. how does sciatic nerve cause a sympathetic blockade?
  2. what is the result of this “blockade”
A

sciatic nerve block complications:

  1. sciatic nerve contains some sympathetic fibers,
  2. blockade causes mild venous pooling
76
Q

Popliteal Fossa Blockade:

  • why block here? what does sciatic nerve become after this point?
  • below the knee medially is covered by what nerve (which is a branch of what nerve)
A

Popliteal Fossa Blockade
• Sciatic nerve blockade prior to division into tibial and peroneal branches
– Below the knee the only portion NOT covered by the sciatic nerve is the medial portion of leg (saphenous coverage-(which is branch of femoral))

77
Q

how to perform a Popliteal Fossa Blockade Classic/Posterior Approach

A

Popliteal Fossa Blockade Classic/Posterior Approach:
• Prone position
• Identify popliteal fossa (draw a triangle)
– Draw a line at the biceps femoris and semitendinosus muscles
– Base of triangle is skin crease behind the knee
(Operative leg should be slightly bent with Foot resting freely above bed).
• From midpoint of base of triangle, measure 7 cm (realis4cally 5-10) up and 1 cm lateral, mark an X
• Skin prep & localize
• Insert needle through X at 45 degree angle cephalad
• Use a fanwise approach perpendicular to the center line until nerve is contacted
• Nerve lies midway between femur and skin
• Set sFmulator iniFally to 1.0 mA
– Foot inversion=:bial and deep peroneal nerves
• Best sensory and motor block!
– Foot eversion= superficial peroneal nerve
– Foot plantar flexion=posterior Fbial nerve
– Foot dorsiflexion= deep peroneal nerve
• Aspirate and Inject 40 ml of LA

78
Q

Popliteal Fossa Blockade Classic/Posterior Approach ULTRASOUND

A

Popliteal Fossa Blockade Classic/Posterior Approach ULTRASOUND:
• Position and landmarks same as non-ultrasound technique
• Transverse plane give best image of sciaFc
• Scan starFng from popliteal crease
• Nerve appears hyperechoic (bright)
• Nerve is lateral to popliteal artery
• Locate sciaFc proximal to split into Fbial and peroneal nerves
• Insert needle at lateral end of probe
• Once nerve is sFmulated inject 40 ml LA

79
Q

how to perform a Popliteal Fossa Blockade Lateral Approach

A

Popliteal Fossa Blockade Lateral Approach:
• Supine position, slight bend in knee
• Locate groove between biceps femoris tendon and vastus lateralis muscle
• Locate lateral epicondyle of femur
• Mark 7 cm(7-10) cephalad to lateral femoral epicondyle
• Set sFmulator to 1.0 mA
• Insert needle in horizontal plane unFl contact with femur
• After contact redirect needle 30 degrees posteriorly (nerve usually 1-2 cm beyond initial femur contact
• Observe for nerve stimulator response in foot or calf (plantar flexion is optimal for complete sensory block
• Aspirate and inject 40 mL of LA

80
Q

Saphenous Nerve Block

  1. origin:
  2. terminal branch of what major nerve?
  3. sensory to where
  4. how bout motor?
A 
Saphenous Nerve Block:
1•  L3-L4
2•  Terminal branch of femoral nerve
3•  Sensory= medial lower leg, distal to knee to medial malleolus (occasional great toe)
4•  Motor= none
81
Q

how to perform saphenous nerve block:

  • position of patient?
  • insert needle at what landmark? and deep to what tissue?
  • inject LA where (what landmark)?
  • how much LA is injected (total)
A

saphenous nerve block:
• Supine
• Insert needle deep to subcutaneous tissue at tibial tuberosity, aim medial toward nerve
• Deposit a subcutaneous infiltraFon of 5-10 ml LA in 5 cm area distal to medial surface of tibial tuberosity to calf

82
Q

what is primary landmark of saphenous nerve block

A

• Primary landmark is tibial tuberosity

83
Q

Ankle Block

  1. used for?
  2. made up of ___ branches of ___&___ nerves?
  3. name the branches:
A 
Ankle Block:
1•  Surgical anesthesia for most procedures on the foot
2•  5 terminal branches of sciatic & femoral nerves:
3. 5 terminal branches:
–  Sural
– Posterior tibial 
– Superficial peroneal 
– Deep peroneal
–  Saphenous
84
Q

ankle block

  1. what is the origin of all the nerve except for one? where does that one come from?
  2. what nerves supply deep foot?
  3. what are the “S” nerves and what type of innervation do they supply?
A

ankle block:
1. All from sciatic nerve except saphenous nerve (from femoral nerve)
2. Tibial and deep peroneal (from sciatic) supply deep structures of the foot
3. Superficial peroneal, Sural (from sciatic), Saphenous (from femoral)
supply sensory innervation.
Blocked superficially…they made that easy with all Starting with the letter S!

85
Q

Ankle Block Posterior Tibial Nerve

  1. origin:
  2. location:
  3. gives rise to branches behind__ __?
  4. supplies ___
A 
Ankle Block Posterior Tibial Nerve
1•  L4-S3
2•  Location:
	–  Medial aspect of Achilles tendon
	–  Posterior to posterior Fbial artery
3•  Gives rise to terminal branches behind medial malleolus
4•  Supplies bottom of foot
86
Q

Ankle Block Posterior Tibial Nerve:

  • perform wheal where?
  • insert needle toward what bone and posterior to what?
  • what should you elicit and where?
  • how much LA is injected (after what?)?
A

Ankle Block Posterior Tibial Nerve
• Skin prep
• LA skin wheal along medial aspect of Achilles tendon at superior boarder of MM
• Insert needle toward posterior tibia, posterior to artery
• Elicit paresthesia (sole of foot)
• Inject 3-5 ml LA after negative aspiration

87
Q

Ankle Block Sural Nerve:

  • what is it (and what is it comprised of)?
  • where is it located?
A

Ankle Block Sural Nerve
• Cutaneous nerve from tibial and common peroneal nerves
• Location– Lies subcutaneously behind lateral malleolus

88
Q

sural nerve:: what does it supply?

A

• Supplies lateral foot, and lateral part of 5th toe

89
Q

Ankle Block Sural Nerve: how to perform:

  • where is wheal performed at?
  • needle is inserted how many cm toward what?
  • inject LA into __tissue in a fanwise manner from___ tendon to ____bone?
  • how much LA total is injected?
A

Ankle Block Sural Nerve
• Skin prep
• Skin wheal lateral to Achilles tendon at level of lateral malleolus
Insert needle 1 cm toward lateral boarder of fibula
• Inject 3-5 ml LA, subcutaneously, in fanwise manner from lateral boarder of Achilles tendon to lateral boarder of fibula

90
Q

Ankle Block: Superficial Peroneal

  • what type of nerve
  • what is its origin?
  • where does it become superficial?
  • what does it supply innervation to?
A 
Ankle Block Superficial Peroneal:
•  Superficial nerve (L4- S2)
•  From common peroneal nerve
•  Becomes superficial at ankle
•  Supplies dorsum of foot and toes
91
Q

Ankle Block Superficial Peroneal: how to perfom-

  • what are landmarks?
  • what type of injection?
  • between what 2 landmarks?
  • how much LA total?
A

Ankle Block Superficial Peroneal:
• Locate anterior boarder of tibia (extensor hallicus longus is a landmark) and superior aspect of lateral malleolus
• Blocked by subcutaneous infiltration of 5 ml LA between 2 points
• SQ wheal from extensor hallicus longus to lateral malleolus

92
Q

where is deep peroneal artery (what is it near)?

A

Deep peroneal nerve is lateral to artery

93
Q

Ankle Block: Deep Peroneal nerve facts:

  • what nerve does it come from
  • at level of malleoli, where does this nerve lie?
  • what is it lateral to and what should we use for landmarks?
A

Ankle Block Deep peroneal:
• From common peroneal nerve (L4-S2)
• At level of malleoli nerve lies between anterior tibial and extensor hallicus longus muscles
• (And lateral to anterior tibial artery…not the best landmark!) Use tendons

94
Q

Ankle Block:Deep peroneal nerve facts:

-what type of innervation? to where?

A

Ankle Block Deep peroneal:
• Motor= short extensors of toes
• Sensory= adjacent areas of first and second toes

95
Q

How to perform an Ankle Block Deep peroneal:

  • identify what tendons (how)?
  • identify what else (cause you dont want to hit it!)?
  • where is needle inserted?
  • what is LA injected into?
  • how much LA (total)?
A

How to perform an Ankle Block Deep peroneal:
• Identify: Extensor hallicus longus muscle tendon (extend great toe to identify tendon) & anterior tibial tendon at level of malleoli
• Identify artery
• Insert needle just lateral to artery between 2 tendons
• Inject 3-5 ml LA after negative aspiration deep into fascia

96
Q

Saphenous nerve: facts:

  • originates from what nerve?
  • courses where and what vein does it follow?
  • where does it follow that vein to?
  • what type of innervation and to where?
A

Saphenous nerve:
• Originates from femoral nerve
• Location
– Courses subcutaneous at medial aspect of knee
– Follows great saphenous vein to medial malleolus
• Sensory= medial aspect of foot

97
Q

how to perform a Saphenous Ankle Block:

  • where is the local injected?
  • is it deep or SQ?
  • how much total LA is injected?
  • what 2 nerves does a semi circle of SQ injected LA (from ___(landmark) to ____(landmark) block?
A

how to perform a Saphenous Ankle Block?
• Blockade by subcutaneously injecting 3-5 ml LA proximal and anterior to medial malleolus to anterior boarder of tibia (front of ankle)
• Goal= semi circle of LA from lateral to medial malleolus blocks superficial peroneal and saphenous

98
Q

Ankle Block Complications

  1. how often?
  2. what are they?
A 
Ankle Block Complications
1•  Rare
2	•  Neuropathy
	•  Avoid intra-neural injections 
	•  Intravascular injection
99
Q

what innervation is blocked with obturator block?

A

obturator block:
Motor: adductor muscles of thigh, hip, knee joints
Sensory: skin medial to thigh

100
Q

which nerves would be blocked for knee arthroscopy?

A

nerves needing block for knee arthroscopy:

femoral, LFC, sciatic and obturator nerve block

101
Q

what nerves would be blocked for a foot procedure (ankle block)?

  1. how many?
  2. which ones?
A
  1. 5 individual nerves blocked:
  2. Tibial
    deep peroneal
    Superficial peroneal
    Sural
    Saphenous
102
Q

what nerves would be blocked for an ACL surgery?

A

-femoral –after the surgery

or femoral, sciatic, LFC and obturator.

103
Q

track the path of the femoral nerve from its rami to its terminal branches:

A

path of the femoral nerve from its rami to its terminal branches:

  • caudal (anterior) lumbar plexus (T2-4)
  • anterior division
  • posterior division
104
Q

track path of femoral lateral cutaneous

A
  • anterior caudal rami L2-L4 of lumbar plexus

- continues into lateral thigh

105
Q

track the path of the sciatic nerve:

A

path of the sciatic nerve:

  • lumbosacral plexus (L4-S3)
  • tibial nerve and common fibular nerve??

c. regional exam 3 (w13) (2 decks)

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