Dr S. Parthasarathy MD DA DNB PhD FICA , Dip software based statistics Lumbar plexus blocks Dr S. Parthasarathy MD DA DNB PhD FICA , Dip software based statistics

Hence we go for spinal or epidural !! Upper limb One brachial plexus Easy to access Easy to test and administer Lower limb Lumbar and sacral plexus Difficult to access Late onset .

Anatomy The lumbar plexus is an anastomotic complex formed by the anterior roots from L1 to L3 and the greater part of L4. There is frequent anastomosis between the upper part of the plexus with the subcostal nerve and between the L4 rami and the lumbosacral trunk ( nervi fucralis) Into the psoas – from the psoas

Anatomy The plexus passes peripherally after its exit from the intervertebral foramina, usually covered by the psoas muscle The genitofemoral nerve and the lateral cutaneous nerve of the thigh leave the plexus soon after the iliohypogastric and ilioinguinal nerves have split off.

The first lumbar nerve, which contains a branch from the twelfth thoracic nerve, divides into an upper branch (iliohypogastric nerve and ilioinguinal nerve) and a lower branch (genitofemoral nerve)..

Most of the second, third, and parts of the fourth lumbar nerves form ventral branches, from which the femoral nerve and obturator nerve branch The lateral femoral cutaneous nerve is formed from fibers of the ventral branches of L2/L3.

Nerves iliohypogastric Ilioinguinal Genitofemoral Lateral femoral cutaneous Femoral Obturator

The iliohypogastric nerve penetrates the transversus abdominis muscle near the crest of the ilium and supplies motor fibers to the abdominal musculature. It ends in an anterior cutaneous branch to the skin of the suprapubic region and a lateral cutaneous branch in the hip region

Femoral The femoral nerve(L2/L4) is the largest nerve of the lumbar plexus and provides the sensory innervation of the front of the thigh, while its sensory terminal branch, the saphenous nerve, innervates the inside of the lower leg as far as the ankle. The femoral nerve passes anterior to the psoas muscle under the inguinal ligament through the muscular lacuna and is the motor nerve for the quadriceps femoris, sartorius, and pectineus muscles.

The lateral cutaneous nerve of the thigh (L2/3) passes over the iliacus muscle medial to the anterior superior iliac spine under the inguinal ligament and is a purely sensory nerve innervating the skin on the lateral side of the thigh.

The obturator nerve(L2/L4) leaves the plexus medial to the psoas muscle and passes through the obturator canal together with the obturator vein and artery to the inside of the thigh Anterrior and posterior branches Supply adductors Medial side of knee – skin innervation

Clinical Assessment of Lower Extremity Nerve Blocks push, - tibial pull, - common peroneal pinch- lateral femoral cutaneous Punt – femoral

push, pull, pinch, punt.

Indications Anesthesia- wound care, SSG, muscle biopsy Analgesia – positioning before spinal or periop analgesia CRPS Vasoocclusive disease Postamputation pain Edema in the leg after radiotherapy Diabetic polyneuropathy

How to block plexus Psoas compartment block Three in one inguinal perivascular block

CHEYEN technique Psoas compartment block

Position : Lateral, with the surgical side up. Common Indications: Anesthesia and immediate postoperative analgesia for hip, femur, or knee surgery. Needle Size: 21-gauge, 100-mm insulated needle. Volume: 20 to 30 mL 0.5% or 0.2% ropivacaine depending on the indication.

Intercristal line – PSIS cross – 4 cm from midline

Needle perpendicular 4- 5 cm – transverse process Cranially – cross quadratus 1.5 mA current Hamstring contraction 0.5 mA Inject slow

Psoas muscle – hip contraction – withdraw Abdominal muscle – ILIH - go lateral No bone – go medial Labial paresthesia – genitofemoral - go lateral Erector spinae – go deep Hamstring muscles = go cranially

Usually 30 ml Onset may be 15 -- 25 minutes Medial side knee – sensory loss – saphenous sign Sedation with midazolam and fentanyl is ideal Quadriceps and adduction thigh Monitor 45 minutes Other side sensory testing

MRI picture and flow of local anesthetics Proved obturator block in 90 %

Continuous plexus blocks Touhy needle Quadriceps contraction Catherter cranial 8 cm in 5 ml / hour infusion of dilute ropivacaine PCA 5ml/ 30 minutes

Toxicity – may be there because of muscle compartment and large volume Nerve injury – rare Vascular injury – rare Epidural – may be there and hypotension – with resuscitative ready Usually unilateral sympathectomy – no hemodynamic consequences

Femoral , LFCN and obturator Three in one block Femoral , LFCN and obturator Attack from below

Winnie description first Cephalad flow along a fascial layer supine with both legs extended and the leg to be blocked with 15–30 degrees lateral rotation. Nerve stimulation and quadriceps twitch USG

Iliopsoas or bone hit – come superficial Sartorius – go deep and lateral Vessel – femoral artery – go lateral No response – gone too lateral – come medial Usually 20 ml Not much sedation required Obturator may be missed

Femoral nerve block The femoral nerve enters the thigh at the level of the inguinal ligament lateral to the femoral artery, divides slightly distal to the inguinal ligament in branches, insert close to the distal ligament when performing the 3-in-1 block. The femoral nerve supplies motor branches to the quadriceps femoris, sartorius, and pectineus muscles, and its sensory branch (saphenous nerve) innervates the anterior-medial side of the lower leg down to the medial ankle

Just below inguinal ligament Lateral to femoral artery Perpendicular insertion Quadriceps contraction OR USG

Probe vessels and the nerve

Femoral Vs 3 in one Operations on the anterior thigh (i.e. lacerations, skin graft, muscle biopsy) Pin or plate insertion/removal (femur) Femur fractures Same indications as femoral nerve block Analgesia and anesthesia of the hip (dislocations, femoral neck fractures) Analgesia of the knee Volume and distal pressure

Lateral femoral cutaneous nerve The lateral femoral cutaneous nerve (LFCN) divides into approximately two to five branches innervating the lateral and upper aspects of the thigh. Pain relief Meralgia paresthetica SSG

The lateral femoral cutaneous nerve typically is located between the tensor fasciae latae (TFLM) and sartorius (SaM) muscles, 1 to 2 cm medial and inferior to the anterior superior iliac spine (ASIS) and 0.5 to 1.0 cm deep to the skin surface 1 ml is enough

Obturator nerve block treat hip joint pain and is used in the relief of adductor muscle spasm associated with hemiplegia or paraplegia, cerebrovascular pathology, medullar injuries, multiple sclerosis, and infantile cerebral palsy. Possible in TURBTs

1.5 cm caudad and lateral to pubic tubercle 2 – 4 cm – anterior Slide posterior Pubic ramus Cranial and lateral 2 cm 10 ml local Weak adduction

Summary Lumbar plexus – anatomy and the main nerves Indications - Types of blocks Procedure and tricks Three in one Femora, LFCN and obturator

Thank you all