Download Sciatic nerve block MGMC

Sciatic nerve block
Dr. S. Parthasarathy
MD., DA., DNB, MD (Acu), Dip. Diab. DCA, Dip.
Software statistics
PhD (physio)
Mahatma Gandhi Medical college and research institute ,
puducherry India
Indications
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one of the largest nerve trunks in the body
Combined with other blocks for anaesthesia
Analgesia for ankle fractures
Transport analgesia
Trauma analgesia
Volume
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20 – 25 ml is adequate
Volume problem ??
But absorption is less quick
Motor block – 0.5 % or 0.25 % bupivacaine
Anatomy
• L 4 to S3 roots
• roots of the sacral plexus form on the anterior
surface of the lateral sacrum
• assembled into the sciatic nerve on the
anterior surface of the piriformis muscle
• sciatic nerve exits the pelvis, is joined by the
posterior cutaneous nerve of the thigh
Anatomy
• posterior to the obturator internus, the
gemelli, and the quadratus femoris. At this
point, these nerves are anterior to the gluteus
maximus.
• equidistant from the ischial tuberosity and the
greater trochanter.
• continues downward through the thigh to lie
along the posteromedial aspect of the femur.
At popleteal fossa, divides to tibial and
common peroneal nerves
Anatomy
Anatomy
Anatomy – lateral view
Classic technique ( Labat )
• The patient is positioned laterally, with the
side to be blocked nondependent.
• The nondependent leg is flexed and its heel
placed against the knee of the dependent leg
The anesthesiologist is positioned to allow
insertion of the needle
Needle Puncture
• A line is drawn from the posterior superior
iliac spine to the midpoint of the greater
trochanter.
• Perpendicular to the midpoint of this line,
another line is extended caudomedially for
5 cm.
• The needle is inserted through this point
Technique
• 22-gauge, 10- to 12-cm needle is inserted,
• The needle should be directed through the
entry site toward an imaginary point where
the femoral vessels course under the inguinal
ligament
• Paraesthesia or motor response.
• Bone hits . Go towards trochanter but not
more than 2 cm
Anterior technique( BECK)
• supine patient
• leg in neutral position
• a line should be drawn from the anterior
superior iliac spine to the pubic tubercle.
Another line should be drawn parallel to this
line from the midpoint of the greater
trochanter inferomedially,
Anterior Approach
Technique
• At the point,the perpendicular line crosses the
more caudal line,
• a 22-gauge, 12-cm needle is inserted so that it
contacts the femur at its medial border. Once
the needle has contacted the femur, it is
redirected slightly medially to slide off the
medial surface of the femur.
• Then paraesthesia , 20-25 ml.
Parasacral sciatic nerve block
(Mansour):
• Line from p.s.i.spine to
ischial tuberosity
• 6 cm caudad
• Perpendicular needle
insertion 5-7 cm
• Bone , slip caudad,
• get nerve stimulation –
dorsiflex foot
Raj approach
• patient supine
• hip and knee flexed to
90°,
• the greater trochanter
and ischial tuberosity
are marked. A line is
drawn
• intermuscular groove
between the adductors
and the hamstrings
marked
Ischianagi’s approach, lateral
midfemoral
• Supine
• Posterior to posterior
border of greater
trochanter
• Needle directed
medially
• Cant position- ideal
technique
Problems
• Dysaesthesias
• Failure because of the necessity of combined
blocks
Ultrasound guided block
USG probe
USG image
USG image
Before and after LA
Thank you all