what do lower extremity nerve blocks provide
high quality of anesthesia and analgesia for the lower extremity
lower limb regional anesthesia advantages
decreased PACU time n/v urinary retention increase post op analgesia
lower limb regional anesthesia yields decreased
hospital stays and admissions
hospital and patient cost
lumbar plexus provides innervation to the lower extremities nerve supply to lower extremity is composed of
lumbar plexus
sacral plexus
the lumbar plexus lies with what muscle and branches into where
psoas
branches into the proximal thigh
lumbar plexus primaries arrives
L1-L4
lumbar plexus comes from 3 major nerves
lateral femoral cutaneous L2-L3
Obturator L2-L4
femoral L2-L4
what nerve is frequently injured in pelvic surgery
obturator
what is the largest branch of the lumbar plexus
femoral nerve
the upper lumbar division supplies what two nerves
iliohypogastric nerves
ilioinguinal nerves
what nerves combine with thoracic nerves innervates the trunk above the extremity
iliohypogastric nerves
ilioinguinal nerves
sacral plexus is derived from
anterior rami of the L4 and L5 and S1-S4
what is the largest nerve trunk in the body
Sciatic L4-S3
what nerves arise from the sacral plexus
sciatic L4-S3
Posterior Cutaneous nerve S1-3
terminal branches-tibial and common peroneal
what forms the sciatic and supplies both motor and sensory innervation to posterior aspect of the lower extremity and foot
sacral plexus
what four major nerves supply all of the lower extremity
lateral femoral cutaneous nerve
femoral nerve
obturator nerve
sciatic nerve
-posterior cutaneous nerve of thigh (s1-s3)
what are the indications for lumbar plexus block
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)
Posterior Lumbar Plexus (Psoas Compartment) block: position:
Lateral (or Prone, lying over soft pillow)
Position: lateral (side to be blocked in the nondependent position/up)
Posterior Lumbar Plexus (Psoas Compartment) block
Landmarks
4cm lateral to L4 Spinous processes
Posterior Lumbar Plexus (Psoas Compartment) block
Anatomy
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….
Posterior Lumbar Plexus (Psoas Compartment) block
complications:
Retroperitoneal hematoma
Intravascular LA injection (toxicity)
Intrathecal and/or epidural injection
Renal capsular puncture (hematoma)
what two ways can be lumbar plexus block be done
prone or lateral positions
what is the advantage of a prone position to block the lumbar plexus (psoas)
a more stable resting hand position, allowing more precise scanning and manipulation
when preforming a lumbar block what care should be taken
frequent aspiration and injecting local anesthetic in small increments to detect epidural or spinal spread early
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
high plasma levels
how do we identify the lumbar plexus
use of nerve stimulator
for lumbar plexus block can continuous catheterization be used for prolonged analgesia
yes
the lumbar block is ideal for what type of surgeries
hip surgeries and surgeries above the knee
when the lumbar block is combined with the sciatic nerve block what does it provide
complete unilateral lower limb anesthesia suitable for lower extremity surgeries.
the lumbar block does not supply complete anesthesia to the lower extremity- why is this?
does not supply complete anesthesia of lower extremity because it cann’t achieve blockade of the sacral roots that supply the sciatic nerve
for lumbar block how where does the bevel of the needle face
bevel facing caudad and lateral
technique for lumbar plexus block
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)
lumbar plexus length and needle size
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
the lumbar plexus block needle is advanced in an terror direction in the posts compartment
The needle is advanced in an anterior direction until in the Psoas compartment (a femoral motor response is elicited (quadriceps) at 0.5 mA)
after proper position how much local anesthetic is injected into the lumbar plexus
20-30 ml
greater than 20 may increase risk of bilateral spread
how long for the local anesthetic to spread to the roots of the lumbar plexus
15-20min
lumbar plexus depth
men
women
men 8.4cm
women 7.1cm
If transverse process is contacted in lumbar block
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.
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
elderly and obese patients.
which block has the highest complications
lumbar plexus block