Dr.D.KANNAN. D.A., D.N.B.,
Consultant Anaesthesiologist,
Meenakshi Mission Hospital And Research Centre,
Madurai.
•Introduction
•Nerve stimulator
•Drugs and toxicity
•Advantages of block
•Anatomy
•Nerve blocks
• Femoral N
•Obturator N
•Sciatic N
•Saphenous N
•Ankle block
•Nerve Stimulator
•Unipolar needles of varying length
•Flexible catheter
•Electrode
Current range from 0.1-5.0 mA
Pulse Frequency
1 Hz -Mixed nerve
2 Hz
- Sensory nerve
The electrical current required to
trigger muscle contractions correlates
with the distance of the tip of the
needle to the nerve.
That means that the closer the needle
is to the nerve, the lower the electrical
current that is required to induce
contractions or sensory responses
1.
2.
3.
4.
5.
Initial current
2-3 mA
Frequency
1-2 Hz
Threshold current
0.3- 0.5 mA
Aspiration test
5- 10 ml LA injected slowly
Increase the current to initial level
No stimulatory response - inject the remaining drug
Recurring response - May indicate intra vascular
needle position
•2% Plain Lignocaine
3 mg / kg
•2% Lignocaine with adrenaline
• 0.5% Bupivacaine
• o.75 % Ropivacaine
7 mg / kg of
2 mg / kg
2-3 mg / kg
• Analgesic: 0.125% Bupivacaine, 0.2% Ropivacaine,
•
Opiods, Clonidine.
•On Arrival block
•Preemptive analgesia
•Post operative pain relief
•Rescuing a risky patients
•Less complications
•Cost factor
•The innervations of the leg is derived from the lumbar and
sacral plexuses
•Lumbar plexus formed by T12–L4
The main branches are
1.Lateral cutaneous N of thigh
2.Femoral N
3.Genitofemoral N
4.Obturator N
Lumbo sacral plexus formed by L4 –S5
Main branches are
1.Sciatic nerve
2.Posterior cutaneous nerve of thigh
3.Pudental nerve
Lateral cutaneous N of thigh
Femoral N
Genitofemoral N
Sciatic N
Obturator N
Pudental N
1.
Lateral cutaneous nerve of thigh
2. Femoral nerve
3. Sciatic nerve
4. Obturator nerve
•Femoral Nerve Block
•Obturator Nerve Block
•Lateral cutaneous Nerve Block
•
Trans gluteal
•Sciatic Nerve Block
•
Popliteal
•Saphenous Nerve Block
•Ankle Block
Indications
•Operative procedures in areas supplying the
femoral and lateral femoral cutaneous nerves
•In combination with proximal sciatic nerve block,
operative procedure on the whole leg.
•Analgesia
Contraindications
• No particular
Side effects / complications
•Vessel puncture (of the femoral vein or artery)
•Anatomical landmarks
•Groin
•Femoral artery
•Anterior superior iliac spine
•Pubic tubercle
•Inguinal ligament
Blockade technique
The patient lies on his
back, his leg loosely
abducted and turned to
the outside.
Puncture site:
2cm caudad to the groin,
1 – 2 cm lateral to the
femoral artery.
Puncture direction: 30 ̊ –
40̊ cranial parallel to the
artery.
Puncture depth: 2 – 4 cm.
Positive stimulatory
response from the femoral
nerve: Rectus muscle of the
thigh (“dancing patella”).
Stimulation of the Sartorius muscle (medial contraction)
occurs
Puncture direction usually too medial.
Retract the needle,
and shift it slightly to the lateral.
Direct stimulation of the Sartorius muscle (rare):
Puncture direction is usually too lateral
Shift the needle slightly to the medial.
Femoral artery puncture:
Retract the needle
Shift puncture direction to the lateral.
•LA injection in the case of Sartorius muscle
stimulation.
•Intravascular injection
Indications
•Suppression of the adductor reflex for the transurethral
lateral bladder wall resection.
•Treatment of adductor spasm.
•Adjunct to the femoral nerve blocks for postoperative
medial knee joint pain.
•Analgesia.
Contraindications
No particular
Side effect / complications
Vessel puncture (obturator artery or vein)
•
Origin of adductor longus muscle
•
Pubic tubercle
•
Femoral artery
•
Anterior superior iliac spine
Blockade technique
The patient is supine on his back, his
leg is rotated outwardly and abducted.
Puncture site:
5 – 10 cm beneath the pubic tubercle
directly lateral to the tendon origin of
the adductor longus muscle.
Puncture direction approx. 45 ̊ craniolateral
pointing towards the anterior iliac spine.
Puncture depth: 4 – 6 cm.
Positive stimulatory response from adductor
group.
Persistent adductor spasm despite proper ONB
Perform additional femoral block
Note
The adductor reflux for TURP can reliably
suppressed by separate Obturator Nerve block
Not by Femoral N block nor Spinal anaesthesia
Indications
•Operative procedure in areas supplying the
sciatic nerve
•In combination with psoas compartment block /
femoral nerve block for operations on the whole
leg
•Analgesia
Contraindications
No particular
Side effects / complications
Vessel puncture (inferior gluteal artery)
Anatomical landmarks
1.
Greater trochanter
2.
Posterior superior iliac spine
3. Ischial tuberosity
4. Sacral hiatus
5. Puncture site
Blockade technique
The patient is placed in the
lateral recumbent position;
hip flexed 45 ̊, knee flexed
70 ̊(“Stable recumbent
position”)
4 – 5 cm mediocaudal on the midperpendicular lines between greater
trochanter and posterior superior iliac
spine; connecting line between the
greater trochanter and sacral hiatus
intersects the insertion point at the
mid-perpendicular line.
Puncture depth
5 – 8 cm
Positive stimulatory response
From the peroneal or tibial nerves:
Extensors or flexors of the foot or toes
Dosage
20-40 ml
Contraction of the Gluteus maximus muscle
(= direct stimulation) occurs:
Continue to advance the needle until the
typical response is elicited.
Stimulatory response from the ischiocrural muscle
group:
LA injection possible Delayed onset of action
Bone contact, No Stimulatory response:
Correct insertion direction to midline between greater
trochanter and ischial tuberosity
Potential errors and hazards
LA injection upon stimulatory response from the
gluteal muscles.
Indications
•Operation procedure in the area supplying the
sciatic nerve of the lower leg and foot
In combination with saphenous nerve block,
operations on the whole lower extremity.
•Analgesia.
Contraindications
•Stent (relative)
Side effects / complications
•Vessel puncture (popliteal artery/vein)
•Anatomical landmarks
•Popliteal fossa
•Popliteal fold
•Long head of the biceps femoris
muscle
•Medial and lateral epicondyle of the
femur
Blockade technique
Patient is either in prone position
or lying on his side, leg extended
Puncture site
8-12 cm above the fold of popliteal
fossa at the medial edge of biceps
femoris muscle.
Puncture depth
2-4 cm
Positive stimulatory response
From the Peroneal and Tibial nerve
(extensors or flexors of the foot or toes)
Dosage: 30 – 40 ml
Femur contact occur:
Insertion too deep and too medial
Retract the needle Correct direction or insertion
site to the lateral, reduce insertion depth.
Vessel puncture popliteal artery/vein:
Puncture too depth and too medial
Retract the needle Correct insertion direction to
the lateral, reduce insertion depth.
Puncture site is too for caudad (popliteal fold):
It may be that the tibial (med.) and perpneal nerve (lat.)
are separated so far apart that complete blocked cannot be
achieved with a single LA injection at the two sciatic
branches.
Indications
•Operative procedures in the area supplying the
saphenous nerve.
•In combination with distal sciatic nerve block for
operations on the whole lower leg and foot.
•Analgesia.
No contraindications /side
effects
Anatomical Landmarks
Petellar crest
Sartorius muscle
Vastus medialis muscle
Blockade technique
Patient lies on his supine back with extended leg
in neutral position, rotated slightly outwards.
Puncture site:
Approx. 2 – 4 cm cranial and medial of the upper
patellar crest over the sartorius muscle. Puncture
direction perpendicular through the muscle up to
the subsartorial fatty tissue.
Puncture depth:
3 – 5 cm.
Positive response include paresthesias on the
medial lower leg at a pulse duration of 1.0 ms.
Dosage
10 – 15 ml LA
Motor stimulatory response comes from the
Vastus medialis muscle
Consider as positive
Inject the drug
Alternative technique
Subcutaneous infiltration below the medial knee
joint from the medial head of gastronemius
muscle to the tibial tuberosity
An ankle block is essentially a block of four branches of the
sciatic nerve
Deep Peroneal N
Superficial Peroneal N
Tibial N
Sural N
one cutaneous branch of the femoral nerve
Saphenous N
Indications:
Surgery on foot and toes
Nerves:
Two deep nerves: Posterior tibial, deep peroneal
Three superficial nerves: superficial peroneal, sural,
saphenous
Never use an epinephrine-containing local anesthetic
Local anesthetic: 6 mL per nerve
•Located immediately lateral to the
tendon of extensor hallucis longus and
medial to the extensor digitorum longus
•The pulse of the anterior tibial artery
(dorsalis pedis) can be felt at this location
• The nerve is immediately lateral to the
artery.
•Located just behind and distal to the
medial malleolus.
•The pulse of the posterior tibial artery
can be felt at this location
• The nerve is just posterior to the artery.
.
Blockade of all three nerves is
accomplished using a simple
circumferential injection of
local anesthetic
subcutaneously.
Residual paresthesias due to an inadvertent intraneuronal
injection.
Vascular puncture
Avoid puncturing the greater saphenous vein and Dorsalis
pedis artery
Systemic toxicity is rare because of the distal location of
the blockade.
Thank you