lumbar plexus

Question 1

what do lower extremity nerve blocks provide

Answer 1

high quality of anesthesia and analgesia for the lower extremity

Question 2

lower limb regional anesthesia advantages

Answer 2

decreased 
PACU time
n/v
urinary retention 
increase post op analgesia

Question 3

lower limb regional anesthesia yields decreased

Answer 3

hospital stays and admissions

hospital and patient cost

Question 4

lumbar plexus provides innervation to the lower extremities nerve supply to lower extremity is composed of

Answer 4

lumbar plexus

sacral plexus

Question 5

the lumbar plexus lies with what muscle and branches into where

Answer 5

psoas

branches into the proximal thigh

Question 6

lumbar plexus primaries arrives

Answer 6

L1-L4

Question 7

lumbar plexus comes from 3 major nerves

Answer 7

lateral femoral cutaneous L2-L3

Obturator L2-L4

femoral L2-L4

Question 8

what nerve is frequently injured in pelvic surgery

Answer 8

obturator

Question 9

what is the largest branch of the lumbar plexus

Answer 9

femoral nerve

Question 10

the upper lumbar division supplies what two nerves

Answer 10

iliohypogastric nerves

ilioinguinal nerves

Question 11

what nerves combine with thoracic nerves innervates the trunk above the extremity

Answer 11

iliohypogastric nerves

ilioinguinal nerves

Question 12

sacral plexus is derived from

Answer 12

anterior rami of the L4 and L5 and S1-S4

Question 13

what is the largest nerve trunk in the body

Answer 13

Sciatic L4-S3

Question 14

what nerves arise from the sacral plexus

Answer 14

sciatic L4-S3

Posterior Cutaneous nerve S1-3

terminal branches-tibial and common peroneal

Question 15

what forms the sciatic and supplies both motor and sensory innervation to posterior aspect of the lower extremity and foot

Answer 15

sacral plexus

Question 16

what four major nerves supply all of the lower extremity

Answer 16

lateral femoral cutaneous nerve

femoral nerve

obturator nerve

sciatic nerve
-posterior cutaneous nerve of thigh (s1-s3)

Question 17

what are the indications for lumbar plexus block

Answer 17

when unilateral block is desirable

when spinal or epidural anesthetic is contraindicated for operations of hip thigh or upper leg

useful for surgical procedures involving areas innervated by femoral, lateral femoral cutaneous and obturators nerves (procedures on hip, knee and anterior thigh)

Question 18

Posterior Lumbar Plexus (Psoas Compartment) block: position:

Answer 18

Lateral (or Prone, lying over soft pillow)

Position: lateral (side to be blocked in the nondependent position/up)

Question 19

Posterior Lumbar Plexus (Psoas Compartment) block

Landmarks

Answer 19

4cm lateral to L4 Spinous processes

Question 20

Posterior Lumbar Plexus (Psoas Compartment) block

Anatomy

Answer 20

Reaching the posterior lumbar plexus requires a long needle
Depth of transverse process of lumbar vertebrae from the skin is approx 5 cm
Hence, this block has one of the highest complication rates of any peripheral nerve blocks….

Question 21

Posterior Lumbar Plexus (Psoas Compartment) block

complications:

Answer 21

Retroperitoneal hematoma

Intravascular LA injection (toxicity)

Intrathecal and/or epidural injection

Renal capsular puncture (hematoma)

Question 22

what two ways can be lumbar plexus block be done

Answer 22

prone or lateral positions

Question 23

what is the advantage of a prone position to block the lumbar plexus (psoas)

Answer 23

a more stable resting hand position, allowing more precise scanning and manipulation

Question 24

when preforming a lumbar block what care should be taken

Answer 24

frequent aspiration and injecting local anesthetic in small increments to detect epidural or spinal spread early

Question 25

the lumbar paravertebral space is a vascular and muscular space which leads to significant systemic absorption of local anesthetic- what is there a potential for

Answer 25

high plasma levels

Question 26

how do we identify the lumbar plexus

Answer 26

use of nerve stimulator

Question 27

for lumbar plexus block can continuous catheterization be used for prolonged analgesia

Answer 27

yes

Question 28

the lumbar block is ideal for what type of surgeries

Answer 28

hip surgeries and surgeries above the knee

Question 29

when the lumbar block is combined with the sciatic nerve block what does it provide

Answer 29

complete unilateral lower limb anesthesia suitable for lower extremity surgeries.

Question 30

the lumbar block does not supply complete anesthesia to the lower extremity- why is this?

Answer 30

does not supply complete anesthesia of lower extremity because it cann’t achieve blockade of the sacral roots that supply the sciatic nerve

Question 31

for lumbar block how where does the bevel of the needle face

Answer 31

bevel facing caudad and lateral

Question 32

technique for lumbar plexus block

Answer 32

palpate midline/spinous process

a line is drawn through the lumbar spinous processes

a line is drawn from iliac crest to iliac crest tuffiers line

palpate posterior superior iliac spine and draw another line cephalad parallel to the spinous process line

The site of needle entry is approximately 4 cm lateral to the spinous processes on the line drawn b/w the iliac crests (Tuffier’s line)

Question 33

lumbar plexus length and needle size

Answer 33

8-15 cm insulated 21 G needle inserted at the point of intersection b/w the transverse line and the intersection of the lateral and middle thirds of the 2 sagittal lines

Question 34

the lumbar plexus block needle is advanced in an terror direction in the posts compartment

Answer 34

The needle is advanced in an anterior direction until in the Psoas compartment (a femoral motor response is elicited (quadriceps) at 0.5 mA)

Question 35

after proper position how much local anesthetic is injected into the lumbar plexus

Answer 35

20-30 ml

greater than 20 may increase risk of bilateral spread

Question 36

how long for the local anesthetic to spread to the roots of the lumbar plexus

Answer 36

15-20min

Question 37

lumbar plexus depth
men
women

Answer 37

men 8.4cm

women 7.1cm

Question 38

If transverse process is contacted in lumbar block

Answer 38

the needle should be withdrawn slightly and walked off the transverse process in a caudal (toward tail) direction (never insert more than 2-3cm past the depth at which the transverse process was catheter- dont go too deep.

Question 39

the lumbar plexus block is a deep block that makes it difficult to appreciate the difference in the echogenicity of the anatomic structures especially in the

Answer 39

elderly and obese patients.

Question 40

which block has the highest complications

Answer 40

lumbar plexus block