Sural Nerve

Everything Green (2)

Femoral and Saphenous Nerves
 
 
 

Obturator Nerve

Which of the following is true:
 

1. The posterior approach to Sciatic N Block usually blocks the Posterior Femoral Cutaneous Nerve
2. Sciatic N courses between greater trochanter and posterior superior iliac spine (PSIS)
3. The femoral nerve is posterior AND lateral to the femoral artery
4. A popliteal nerve block is sufficient for ankle surgery

At the level of the malleoli, list the nerves that need to be blocked for great toe amputation

Superficial Peroneal Nerve
Tibial Nerve
+/- Saphenous Nerve
 
 
 

Fascia Illiaca Block

Indications
THR, femoral osteotomy, femur fx, knee arthroscopy or knee ligament reconstruction, TKR

Technique
Depends on spread of local anesthetic under fascia iliaca
VOLUME 30-40cc
Draw inguinal ligament (ASIS - pubic tubercle).
17G Tuohy, 75 degree angle
1 cm caudal to junction of middle and lateral thirds
2 pops: fascia lata, fascia iliaca
Change to 30 degree angle, advance 1 cm further 
Higher success rate in pediatric patients
 

A 76yo with ankylosing spondylitis is scheduled for TKR. She is unable to turn laterally because of hip pain (bilateral THR planned for future). You consider options for regional anesthesia:
1. What difficulties may you have with SAB?
2. What peripheral blocks? What approach?

K-type: A=1,3; B=1,3; C=2,4; D=4; E=1,2,3,4

Nerve blocks in which the transverse process is used as a guide for needle placement:

1. Psoas compartment block
2. Paramedian epidural placement
3. Paravertebral block
4. Celiac plexus block
 

1. Psoas compartment block
2. Paramedian epidural placement
3. Paravertebral block

You are doing a peripheral nerve block on a sleeping 20 kg child for intraoperative and postoperative pain relief. You have chosen bupivacaine 0.5% with epinephrine 1:200,000 as your local anesthetic. On your first pass, you identify the correct nerve almost immediately, and have appropriate muscle stimulation at a current of 0.18 mA. How much local can you now safely inject (answer in milliliters)?

None. Pull the needle back, then inject

DAILY DOUBLE!!

1. Sedation taking effect?
2. CNS toxicity from intravascular injection of local?
3. Hypotension from neuraxial spread of local?

Stop injecting local
ABC's

K-type: A=1,3; B=1,3; C=2,4; D=4; E=1,2,3,4

1. Bupivacaine is approximately 70 times more potent than lidocaine in blocking cardiac conduction at heart rates of 60-150
2. Bupivacaine is approximately 20 times more potent than lidocaine in blocking cardiac conduction at heart rates of 60-150
3. In addition to blocking sodium channels, bupivacaine can also block potassium channels.
4. CNS toxicity of local anesthetics in increased by raising the PCO2 and by raising the pH

1. Bupivacaine is approximately 70 times more potent than lidocaine in blocking cardiac conduction at heart rates of 60-150
2. Bupivacaine is approximately 20 times more potent than lidocaine in blocking cardiac conduction at heart rates of 60-150
3. In addition to blocking sodium channels, bupivacaine can also block potassium channels.

K-type: A=1,3; B=1,3; C=2,4; D=4; E=1,2,3,4

1. The 3-in-1 block technique is similar to femoral nerve block, except larger volume is used
2. With 3-in-1 block with nerve stimulation, eliciting quadriceps movement improves the success of the block
3. Saphenous Nerve is the terminal branch of the Femoral Nerve. It provides only cutaneous innervation.
4. The Saphenous Nerve can be blocked by injecting local behind the sartorius muscle.

Lateral Femoral Cutaneous Nerve Block
-landmarks?
-technique?

Ankle Block: landmarks, technique?

Landmarks
Surface: medial malleolus, lateral malleolus, Achilles tendon
Deep: Anterior tibial artery, posterior tibial artery, tibialis anterior tendon, extensor hallucis longus

Technique
Elevate foot on pillow/sandbag to aid needle placement for posterior tibial/sural nerve blocks.
Use 5-7 ml at each nerve, 35-40 ml total.
Avoid epinephrine-containing solutions.
Onset 20-40min.

Blocked at level of superior border of malleoli
(25G 3 1/2 Quincke spinal needle)
Initial needle entry site: midpoint of line joining the medial and lateral malleoli.
Deep peroneal nerve - posterolateral to the pulsations of the anterior tibial artery, between and deep to the tibialis anterior tendon and extensor hallucis longus. Blocked by a deep injection of L.A.
Superficial peroneal nerve - blocked at the superior border of the lateral malleolus.  Blocked by a fascial injection of L.A.
Saphenous nerve - courses posterior to the saphenous vein above the medial malleolus.  Blocked by a fascial injection of L.A.

Blocked at level of malleoli
(25g or 22ga blunt tipped block needle)
Tibial nerve - traverses deep and posterolateral to the posterior tibial artery at the level of the medial malleolus. Blocked by a deep injection of L.A.
Sural nerve - immediately lateral to the Achilles tendon at the level of the lateral malleolus. Blocked by a subfascial injection of L.A.
 
 

Obturator Nerve (L2-4)
Leaves psoas between L5 and S1
Passes through the obturator canal with obturator a and v
Lies on the medial side of the psoas major muscle. 
Divides in thigh into anterior (articular br to hip joint, motor to superficial adductors, and skin of medial distal thigh) and posterior branches (deep adductors, articular br to posterior knee joint)
Rarely done block; useful in adductor spasm pain.

Landmarks/Techniques - 2 choices
1. Supine, leg slightly abducted. 3” needle. 1-2cm lateral and 1-2cm caudad to tip of pubic tubercle. Needle perpendicular to skin, hits ramus of pelvis 1.5-4cm deep; redirect laterally, go 2-3cm deeper. 10-15ml in fanlike manner.
2. Abduct leg. Needle inserted just posterior to the most proximal (tendenous) portion of adductor longus; head towards femoral pulse. N usually 3-6cm deep (leg adduction)

Can use nerve stimulator with either technique - adduction

Which anatomic structures correlate with the lines of the triangle?

• Base: line joining the medial and lateral epicondyles of the femur
• Lateral: tendon of the biceps femoris
• Medial: tendons of semitendinosus & semimembranosus

Landmarks, Technique for Anterior Sciatic Nerve Block

Which nerve?

1-tensor fascia lata, 2-LFCN, 3-sartorius, 4-iliacus, 5-superfic circumflex iliac a, 6-inguinal lig, 7-femoral n, 8-femoral a, 9-femoral v, 10-pectineus, 11-spermatic cord, 12-adductor brevis, 13-adductor longus, 14-rectus femoris

Anatomy Review
Formed from L2-4. Largest nerve of plexus. Leaves the psoas at its posterolateral border at junction of muscle’s upper 2/3 and lower 1/3. Passes in the groove between the psoas and iliacus (supplying both), then lies in the femoral triangle (emergesbeneath the inguinal ligament). Lies on top of the iliacus muscle, one fingerbreadth lateral to the femoral artery (separated by a portion of the psoas muscle). Divides upon entering the femoral triangle into anterior and posterior divisions. Anterior Div -Muscular: to pectineus and sartorius -Cutaneous: intermediate cutaneous nerve of thigh and medial cutaneous nerve of thigh, skin over femoral triangle. Posterior Div -Muscular: quadriceps femoris (rectus femoris, vastus medialis, intermedius, and lateralis) -Cutaneous: saphenous nerve. Supplies an extensive area over the medial side of the knee, leg, ankle and foot -Articular: hip (from rectus femoris) and knee (from all 3 branches to the vasti mm

Femoral Nerve Block
Palpate for the pulsations of the femoral artery at midpoint of inguinal ligament .
Entry site for the 24G, 2-4cm needle is 1cm lateral.
“Pop” through fascia lata and iliaca. 10-15 cc local.
Femoral nerve block needs a long soak time - should be done first when in combination sciatic nerve block
Use of a nerve stimulator and quadriceps response improves accuracy of the block

Nerves selected by probe?

Medial and Lateral Plantar Nerves - terminal branches of Tibial Nerve.
 

Who's Missing?

VISUAL DAILY DOUBLE!!

Last Name?

Deaton

Other than using a nerve stimulator or seeking paresthesias, how can the Femoral Nerve be blocked (list 2 methods)?

1. Blind, based on location relative to femoral artery
(multiple needle passes, blunt needle)
2. Ultrasound guidance

Marhofer P et. al., Regional Anesthesia and Pain Medicine 1998
60 pts for hip surgery after trauma.
Blocks done to provide analgesia for positioning before SAB
Guidance USN (A: 20ml bupivacaine 0.5%) or Nerve Stimulator (B: 20 ml, C: 30 ml)
Success (= block of all three nerves) higher - A: 95% vs B&C: 80%
Onset faster - A: 13+/-16 vs B: 27+/-12, C: 26+/-13

TECHNIQUE
USN Group
USN used to visualize femoral vessels
Femoral n was deep to IPF, 1cm lateral to femoral a.
7cm Sprotte inserted 2cm distal to inguinal lig 30deg cephalad angle.
After penetration of IPF (seen on USN), local injected.

Nerve Stim Groups
Same positioning and needle as above
Looked for quadriceps contraction at <0.3mA

IPF=iliopectineal fascia

Vs. Neuraxial
Less hemodynamic change
Longer pain relief vs. SAB (can place catheters if necessary)
More specific pain control (vs. SAB, epidural)
Often not contraindicated in coagulopathies
Avoid annoying complications (urinary retention, PDPH)
No delay in discharge from PACU

Vs. GA
Decreased complications (trauma to lips, teeth, pharynx, vocal cords; bronchospasm; aspiration; prolonged somnolence; prolonged paralysis from atypical response to NMB; malignant hyperthermia; difficult airway)
Faster wake-up, ambulation, and discharge
N/V less common
Post-op pain minimized

What nerves does the Three-in-One Block anesthetize? How does a single injection get all three nerves?

The URL for an NEW AND EXCITING  (departmental) web page for anesthesia education for residents, nurses, and attendings.

NAMES

1. You are doing a lateral popliteal block. You keep hitting the Popliteal Artery - which way should you redirect the needle to hit the tibial nerve?

2. You have found the tibial nerve ... now where is the common peroneal nerve?

Content:
     Ravindra Prasad, MD

Pictures:
     Brown, Atlas of Regional Anesthesia 2nd Edition
     Brown, Regional Anesthesia and Analgesia (textbook)
     www.imc.gsm.com
     Hahn, McQuillan, Sheplock Regional Anesthesia Atlas
     Various papers, cited above

Design:
     Ravindra Prasad, MD

Hours Work:
     TOO MANY!

Links:
This game, Round 1 or Round 2
Anesthesia Jeopardy Topics List
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