lower limb blocks

LOWER LIMB BLOCKS

Moderator:Moderator: Presented By:Presented By:

Dr. Ani Gopinath Dr. Vijay Kumar

Dr. Geetesh

INTRODUCTION

American surgeons – Halsted and Hall described the

injection of cocaine into peripheral sites in 1880’s.

Peripheral blockade remains a well accepted

component of comprehensive anesthetic care.

Its role has expanded from the operating suite into the

arena of the post-op and chronic pain management.

Lower limb blocks are safe and have certain advanatages

Post-op pain relief.

Lack of complete sympathectomy.

They are less popular than upper limb blocks because

Wide spread acceptance and safety of central neuraxial blockade

Unlike the brachial plexus, nerves supplying the lower extremity are not anatomically clustered where they can be blocked.

Technically more difficult and require more training and practice.

Lower extremity nerve blocks can be divided into:

A)Lumbar Plexus Nerve Blocks:

1. Femoral N. block

2. Obturator N. block

3. Lateral Femoral Cutaneous N. block

4. 3 in 1 block (Inguinal Paravascular Block)

B) Sacral Plexus Nerve Blocks:

1. Sciatic N. Block

2. Popliteal N. Block

3. Ankle Block

ANATOMY OF LUMBAR PLEXUS

Formed by the ventral primary divisions of the first 4

lumbar nerve roots.

Situated in front of the transverse processes of the

lumbar vertebrae posterior to the Psoas major muscle.

Derivatives of this plexus are: Ilio-hypogastric Ilio-inguinal Genito femoral Lateral femoral cutaneous Femoral Obturator

LATERAL FEMORAL CUTANEOUS NERVE BLOCK

Anatomy:

Arises from the dorsal divisions of second and third

lumbar nerves.

Emerges behind the Psoas major muscle while

lying on the Iliacus muscle crosses pelvis

reach anterior superior iliac spine passes under

the inguinal ligament to enter thigh.

Divides into 2 branches, which are distributed to the

anterior & lateral aspects of thigh as far as the knee.


Technique:

Supine position

Anterior Superior Iliac spine and inguinal ligament

identified.

Skin wheal is raised on the skin 2 to 3cms medial to the

iliac spine and just superior to the inguinal ligament.

2inch, 22guage needle is inserted perpendicular to skin

until contact is made with the iliac bone. 10ml of anesthetic

solution injected while the needle being advanced.


Needle is re-introduced 2-3cm medial to spine but 2-

3cms inferior to inguinal ligament. 5-10ml of anesthetic

solution injected.

Indications:

1. In combination with other nerve blocks for surgery of thigh.

2. Neuralgia of thigh.

3. Fascia Lata Pain syndrome

FEMORAL NERVE BLOCK

Anatomy:

Largest branch of lumbar plexus.

Arises from the dorsal portion of the anterior primary

divisions of the 2nd , 3rd & 4th lumbar nerves.

Descends through the psoas major emerge in its lateral

border passes along the pelvic wall on the iliacus

muscle reaches superior pubic ramus & crosses over

passes beneath the inguinal ligament divides into

anterior and posterior divisions.

FEMORAL NERVE BLOCK

It supplies:

Four parts of quadriceps femoris.

Skin of medial and anterior parts of thigh.

Skin of the front and medial side of the leg below

patella (Saphenous nerve)

FEMORAL NERVE BLOCK

Technique:

Mark the inguinal ligament.

Palpate the femoral artery about 2 to 3cms below the

ligament.

Insert a 22 gauge, 3 inch needle perpendicular to skin

until it is just lateral to femoral artery and elicit

paresthesias.

Inject 10ml of anesthetic solution.

FEMORAL NERVE BLOCK

Indications:

In combination with the Lateral Femoral cutaneous nerve

block, it provides anesthesia for many orthopaedic &

plastic surgical procedures.

Very useful in case of Burns, Split Thickness Grafting &

Other procedure as far down as the knee.

Paediatric practice for post-operative pain relief.

OBTURATOR NERVE BLOCK

Anatomy:

Arises from the ventral divisions of the 2nd , 3rd & 4th

lumbar nerves (chief contribution – L3)

Descends through the psoas major muscle brim of

pelvis enters lesser pelvis along the lateral wall

reaches upper part of the obturator foramen

enters the thigh through obturator foramen.

It divides into two branches: Anterior & Posterior


Anterior division supplies:

Adductor longus

Adductor brevis

Gracilis

Hip joint

Posterior division supplies:

Obturator externus

Adductor magnus

Adductor brevis

Knee joint


Technique:

Supine position

Make a skin wheal at a point 2 cm lateral & 2 cm

inferior from pubic tubercle.

Insert a 22 gauge, 3 inch needle perpendicular and

advance until contact is made with bone (Inferior or

Horizontal ramus of pubic bone).

Withdraw the needle and redirect laterally so that the

needle slides off the pubis into the obturator foramen.

Aspirate and then inject 10 ml of anesthetic solution.


Indications:

Painful hip joints.

Adductor muscle spasm especially in paraplegics.

THE INGUINAL PARAVASCULAR TECHNIQUE OF LUMBAR PLEXUS

ANESTHESIA (3 IN 1 BLOCK)

Introduction:

Blocking of three nerves Femoral, Obturator & Lateral

cutaneous with injection of local anesthetic into the

sheath of the femoral nerve in the thigh.

When these nerves emerge from the lumbar plexus,

they are sandwiched between the fascial covering of

Posteriorly Quadratus lumborum

Anteriorly Psoas major


ANESTHESIA (3 IN 1 BLOCK) The compartment continues with Femoral nerve and

extends below the inguinal ligament. Just above the inguinal ligament, Femoral nerve lies in a

groove bounded Medially by Psoas Fascia

Posterolateraly by Iliac Fascia

Anteriorly by Transversalis Fascia

Hence drugs injected into the Femoral sheath will travel

upwards provided Enough volume is given

Pressure is applied below the site of injection.



Technique: Supine position with anesthesiologist standing opposite the

site of operation.

Femoral artery palpated below the inguinal ligament and

retracted medially.

Immobile needle (a short bevel needle with translucent hub

connected by an extension tube to a syringe) inserted lateral

to Femoral artery and angulated cephalad.

The needle is advanced until paresthesia of the femoral

nerve obtained ( response is quadriceps contracture)



The finger palpating Femoral artery is removed and

placed firmly below the needle which facilitates cephalad

movement of anesthetic.

20 to 25 ml of anesthetic solution used.

Simultaneous block of lateral Femoral cutaneous nerve is

recommended.



Indication:

For operation on the thigh.

For management of fracture of Femur shaft.

For acute knee injuries (Along with sciatic N. block)

For knee arthroscopy.

Advantages:

One Injection used.

Less local anesthetic needed.

High success rate.

lower limb blocks

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