sacral plexus block is very much useful procedure in pain management and adjuant to general anesthesia for lower limb surgeries

1. SACRAL PLEXUS
BLOCK

2. • sacral plexus is formed by the union of the first three
sacral nerves and the fourth and fifth lumbar nerves.
• also connects with the ascending division of the fourth
sacral nerve
• sacral plexus is located on the anterior surface of the
sacrum and is separated from the sacrum by the piriformis
muscle
• covered by the parietal portion of the pelvic fascia
• In front of it lie the ureter, the pelvic colon, part of the
rectum and iliac artery and vein

3. • Gives off two sets of branches: Collateral and Terminal
• Collateral : pudendal plexus, hip joint, gluteal structures
adductor and hamstring muscles
• Terminal : greater and lesser sciatic nerves

7. • SACRUM: fused , lower five sacral vertebrae attached to
iliac bones
• Posterior sacral foramina: on each side of fused spinous
processes - posterior divisions of plexus
• Not exactly parallel, angling toward the midline
• Transsacral canal - depth varies from 2.5 cm at S1 to
0.5cm at S4
• Transsacral block and Parasacral Block

8. • INDICATIONS:
• Anesthesia for upper thigh, hip, perineum
• High amputations, relief of sciatic pain
• Obturator block is not achieved
• Immediate access to the individual nerves is not possible

9. Prone position pillow
under the hips
Posterior iliac spine,
sacral Cornu
Skin wheal is raised
lateral and above sacral
Cornu
1cm medial and 1cm
below PSIS

10. Distance between these
wheals is bisected
An additional wheal is
raised at this level
These identify 2,3,4,
sacral foramina
First sacral foramina - 1-
2cm above the 2
foramina in the same
line

12. • Parasacral block: lateral decubitus position, side to be
blocked up
• The dependant limb should be straightened at the knee
and hip, and the limb to be blocked should be flexed at
both hip and knee
• Landmarks

14. • The needle is connected to a
nerve stimulator.
• For a single shot, the needle is
directed perpendicular to the
skin in all planes and strictly
horizontal.
• It is important not to direct the
needle medially

15. • Plantarflexion of the foot or toes (tibial portion) or
Dorsiflexion/eversion of the foot or toes (peroneal
division)
• Contraction of the hamstring muscles (biceps femoris,
semitendinosus) above the knee is associated with the
motor response, most consistent with success.
• The mean depth at which response is obtained - 7cms

16. • More than an isolated sciatic nerve block
• Blocks both components of sciatic and posterior
cutaneous nerve of thigh
• Spread of LA also blocks superior and inferior gluteal,
pudendal, pelvic splanchnic nerves, the terminal portion of
sympathetic trunk, inferior hypogastric plexus and the
obturator nerve

19. PARA SACRAL PARALLEL SHIFT

20. • COMPLICATIONS:
• Excessive volume spread proximally may cause
sympathetic blockade can cause hypotension
• Loss of parasympathetic function to bowel, bladder and
sphincter may occur
• Injection into subarachnoid space is a remote risk
• Needle entering into colon or rectum and bladder and
going unnoticed

21. • References:
• Hadzics
• Cousins and breidenbaugh’s neural blockade and pain
management
• JOURNAL OF NEW YORK SCHOOL OF REGIONAL
ANESTHESIA - PARASACRAL NERVE BLOCK BY
ELIZABETH GAERTNER, MD