1. Lumbar Plexus block & Femoral nerve Block
Presented by
Marwa A. Khairy
Assistant Lecturer of Anesthesia & intensive care
Faculty of Medicine-Ain Shams University

2. MCQs All about lumbar plexus anatomy are true except:
Formed mainly by anterior rami of L1-L4
Receive contribution from S1-S2
Embedded in the psoas ms
Supplies the posterior aspect of the thigh.

3. MCQs The lumbar plexus Block landmark: At the PSIS At the Midline
At point 4 cm lateral to intersection between midline & intercrestal line
At L2-L4 vertebrae

4. MCQs Lumbar plexus Block Advanced technique High volumes are needed
Hemodynamic instability is a potential problem
Not used in anticoagulated patients

5. MCQs
The femoral nerve
Formed by the anterior divisions of the anterior rami of L2–L4.
Supply the adductors of the thigh
Supply the medial aspect of the lower leg via the saphenous nerve.
it is positioned immediately lateral and slightly deeper than the femoral artery

6. MCQs The femoral nerve block
The first sign of onset of blockade is the loss of sensation of the skin over the medial aspect of the leg below the knee (saphenous nerve).
Typical onset time for this block is minutes
Visible twitch of the quadriceps muscle) at MA current is the optimal response.
Carry high risk of postoperative falls.

7. Lumbar Plexus Block Introduction Anatomy Distribution of anesthesia
Patient positioning
Equipment
Nerve stimulator guided technique
US guided technique
Complications

8. Introduction
The lumbar plexus block is an advanced nerve block technique.
The block has significant clinical applicability and because of this, it is used commonly in our practice.
However, this block has a relatively higher potential for complications and should be practiced only after appropriate training

9. Indications
Anterior, medial, and lateral procedures of the thigh including harvest of skin grafts, malignant hyperthermia (MH)-biopsy procedure.
Knee replacement,
Total hip replacement ,hip fractures.
Anterior and posterior cruciate ligament reconstruction.

10. Anatomy of Lumbar Plexus
The lumbar plexus is formed by the anterior rami of the first four lumbar nerves; it frequently includes a branch from T12 and occasionally from L5.
The plexus lies between the psoas major and quadratus lumborum muscles in the so-called psoas compartment.

11. Anatomy of Lumbar Plexus
The lumbar plexus is formed by the anterior rami of the first four lumbar nerves; it frequently includes a branch from T12 and occasionally from L5.
The plexus lies between the psoas major and quadratus lumborum muscles in the so-called psoas compartment.

12. Distribution of Anesthesia
The femoral nerve supplies motor fibers to the quadriceps muscle (knee extension), skin of the anteromedial thigh, and the medial aspect of the leg below the knee and foot.
The obturator nerve sends motor branches to the adductors of the hip and a highly variable cutaneous area on the medial thigh or knee joint.
The lateral femoral cutaneous and genitofemoral nerves are purely cutaneous nerves

13. Patient Positioning
The patient is in the lateral decubitus position with a slight forward tilt.
The foot on the side to be blocked should be positioned over the dependent leg so that twitches of the patella can be seen easily.

14. Equipment
A standard regional anesthesia tray is prepared with the following equipment:
Sterile towels and 4"x4" gauze packs
20-mL syringes with local anesthetic
Sterile gloves, marking pen, and surface electrode
One 1½" 25-gauge needle for skin infiltration
A 10-cm long, short bevel, insulated stimulating needle
Peripheral nerve stimulator

15. Landmarks Landmarks for the lumbar plexus block include: Iliac crest
Midline (spinous processes)
Needle insertion 4-cm lateral to the intersection of landmarks 1 and 2

16. Landmarks Landmarks for the lumbar plexus block include: Iliac crest
Midline (spinous processes)
Needle insertion 4-cm lateral to the intersection of landmarks 1 and 2

17. Technique Local anesthetic skin infiltration
After a cleaning with an antiseptic solution.

18. Technique The needle is inserted at a perpendicular angle to the skin.
The nerve stimulator should be initially set to deliver 1.5 mA current.
The fingers of the palpating hand are firmly pressed against the paravertebral muscles to stabilize the landmark and decrease the skin-nerve distance.
The palpating hand should not be moved during the entire block placement procedure to allow for precise redirections of the angle of the needle insertion when necessary.
The needle is inserted at a perpendicular angle to the skin. The nerve stimulator should be initially set to deliver 1.5 mA current.

19. Technique
As the needle is advanced, local twitches of the paravertebral muscles are obtained first at a depth of a few cms.
The fingers of the palpating hand are firmly pressed against the paravertebral muscles to stabilize the landmark and decrease the skin-nerve distance.
The palpating hand should not be moved during the entire block placement procedure to allow for precise redirections of the angle of the needle insertion when necessary.
The needle is inserted at a perpendicular angle to the skin. The nerve stimulator should be initially set to deliver 1.5 mA current.

20. Technique
The needle is then advanced further until twitches of the quadriceps muscle are obtained (usually at the depth of 6-8 cm).
After the twitches are obtained, the current should be lowered to obtain stimulation between 0.5 mA and 1.0 mA.
At this point, mL of local anesthetic is slowly injected with frequent aspiration to rule out inadvertent intravascular placement of the needle. .
The fingers of the palpating hand are firmly pressed against the paravertebral muscles to stabilize the landmark and decrease the skin-nerve distance.
The palpating hand should not be moved during the entire block placement procedure to allow for precise redirections of the angle of the needle insertion when necessary.
The needle is inserted at a perpendicular angle to the skin. The nerve stimulator should be initially set to deliver 1.5 mA current.

21. Choice of Local Anesthetic
Requires a relatively large volume of local anesthetic
The choice of the type and concentration of local anesthetic should be based on whether the block is planned for surgical anesthesia or pain management.
Due to the highly vascular nature of the area there is high potential for inadvertent intravascular injection, rapid absorption from the deep muscle beds, and epidural spread

22. Choice of Local Anesthetic

23. Block Dynamics and Perioperative Management
Adequate sedation and analgesia are necessary to ensure a still and tranquil patient.
Typically, we use midazolam 4-6 mg after the patient is positioned and alfentanil µg just before needle insertion.
A typical onset time for this block is minutes, depending on the type, concentration, and volume of local anesthetic and the level at which the needle is placed.

24. Block Dynamics and Perioperative Management
The first sign of the onset of blockade is usually the loss of sensation in the saphenous nerve territory (medial skin below the knee).

25. Complications Infection
Hematoma (should not be performed in anticoagulated pts)
Nerve injury
Vascular puncture
Local Anesthetic Toxicity
Hemodynamic consequence (Spread of the local anesthetic to the epidural space may result in significant hypotension and occurs in as many as 15% of the patients)

26. US Guided
Ultrasound Landmarks: The transverse processes of the third and fourth lumbar vertebrae and the psoas muscle.
Transducer Type:
Linear or curved array, 3 to 7 MHz
Transducer Position: Sagittal plane, 4 to 5 cm lateral to the posterior spinous process of the fourth lumbar vertebra

27. US Guided
Longitudinal sonogram of the lumbar paravertebral region showing
an optimal scan for lumbar plexus block
the ‘trident
sign’.

28. Femoral Nerve Block Introduction Anatomy Distribution of anesthesia
Patient positioning
Equipment
Nerve stimulator guided technique
US guided technique
Complications

29. A Common Scenario…..
An 83-yr-old woman (70 kg ) is admitted to the emergency room after a fall in her nursing home. She has fractured the neck of her femur, but otherwise there is no trauma. In addition, she has many medical problems, including coronary artery disease, hypertension, and chronic obstructive lung disease.
On examination, she was cooperative and orientated for time and place. HR 100 atrial fibrillation, blood pressure (BP) 170/100. The electrocardiogram (ECG) shows old MI change with left-axis deviation. Room oxygen saturation is 91%. Her chest is clear, except for crepitations at the bases and increased respiratory wheeze.

30. A Common Scenario…..
Because she is orientated for time and place, she requests a spinal anesthetic, as she is worried about going to sleep. You are happy to oblige and explain that she must either sit up or lie on her side for you to do the spinal. She absolutely refuses and claims this will be very painful.

31. A Common Scenario…..
You attempt to sit her up, but she complains of severe pain. You give her midazolam 0.5 mg and fentanyl 50 mg, slowly. A little later she claims to feel better. However, her oxygen saturation has now fallen to 87% on room air. You give her supplemental oxygen and her saturation improves to 93%. You attempt to sit her up again, but she complains bitterly. You could use a small dose of ketamine so that you can place the spine in a lateral position, but you are concerned about a potentially unacceptable increase in BP with ketamine and the need to use atropine with its side effects.

32. A Common Scenario…..
What else could you do to make her pain free. so that you can perform the spinal block?
You can perform a femoral nerve block

33. Introduction
Femoral nerve block is a basic nerve block technique that is easy to master.
It carries a low risk of complications, and has a significant clinical applicability for surgical anesthesia and post-operative pain management.

34. Indications Anterior thigh surgery ACL repair
Knee arthroscopy (+ intra-articular local)
Femur surgery
Knee arthroplasty (pain management only)

35. Anatomy
The femoral nerve, formed by the dorsal divisions of the anterior rami of L2–L4, is the largest terminal branch of the lumbar plexus.

36. Anatomy
The femoral nerve passes underneath the inguinal ligament into the thigh.
As the femoral nerve passes underneath the inguinal ligament, it is positioned immediately lateral and slightly deeper than the femoral artery

37. Anatomy
At the femoral crease, the nerve it is covered by the fascia iliaca and separated from the femoral artery and vein by a portion of the psoas muscle and the ligamentum ileopectineum.
This physical separation of the femoral nerve from the vascular fascia explains the lack of the spread of a "blind paravascular" injection of local anesthetics toward the femoral nerve.

38. medial aspect of the lower leg via the saphenous nerve
Anatomy
After emerging from the ligament, the femoral nerve divides into an anterior and posterior branch. At this level it is located lateral and posterior to the femoral artery
anterior branch Motor Sartorius and pectineus ms Sensory skin of the anterior and medial thigh
posterior branch
Motor
quadriceps muscles
Sensory
medial aspect of the lower leg via the saphenous nerve

39. Distribution of Anesthesia
A femoral block results in anesthesia of the entire anterior thigh and most of the femur and knee joint.
The block also confers anesthesia of the skin on the medial aspect of the leg below the knee joint (saphenous nerve - a superficial terminal extension of the femoral nerve).

40. Patient position
The patient is in the supine position with both legs extended.
In obese patients, a pillow placed underneath patient's hips may facilitate palpation of the femoral artery and block performance.

41. Patient position
The patient is in the supine position with both legs extended.
In obese patients, a pillow placed underneath patient's hips may facilitate palpation of the femoral artery and block performance.

42. Equipment Sterile towels and 4"x4" gauze packs
20 mL syringes with local anesthetic
Sterile gloves, marking pen, and surface electrode
One 1½" 25-gauge needle for skin infiltration
A 5-cm long, short bevel, insulated stimulating needle
Surface electrode
Peripheral nerve stimulator

43. Landmarks
Landmarks for the femoral nerve block are easily recognizable in all patients and include:
Femoral crease
Femoral artery pulse

44. Landmarks
Needle insertion site is labeled immediately lateral to the pulse of the femoral artery.
All landmarks should be outlined with a marking pen

45. Technique
After a thorough cleaning with an antiseptic solution, local anesthetic is infiltrated subcutaneously at the estimated site of needle insertion.
The injection for the skin anesthesia should be shallow and in a line extending laterally to allow for more lateral needle reinsertion when necessary.

46. Technique
The anesthesiologist is standing on the side of the patient with the pal-pating hand on the femoral artery.
The nerve stimulator is initially set to deliver 1.0 mA (2 Hz, 100 µsec).
The needle is introduced immediately at the lateral border of the artery and advanced in the saggital and slightly cephalad plane

47. Technique The femoral nerve innervates a number of muscle groups.
A visible or palpable twitch of the quadriceps muscle (patella twitch) at mA current is the optimal response.
When the needle reaches the depth of the artery, a pulsation of the hub is visible. Elicitation of a paresthesia or motor response verifies correct needle position. Commonly, the anterior branch of the femoral nerve is identified first. Stimulation of this branch leads to contraction of the sartorius muscle on the medial aspect of the thigh and should not be accepted. The needle should be redirected slightly laterally and with a deeper direction to encounter the posterior branch of the femoral nerve. Stimulation of this branch is identified by patellar ascension as the quadriceps contracts. A total of 20 to 40 mL of solution is injected incrementally after negative aspiration. Reliable anesthesia of the femoral and lateral femoral cutaneous nerves can be achieved with 20 mL. However, an obturator nerve block may not occur even with volumes greater than 30 mL.

48. Choice of local Anesthetic
A femoral block can be accomplished with as little as 10 mL of local anesthetic. However, we often use larger volumes of local anesthetic (e.g., mL), because the local anesthetic often disperses underneath fascia iliaca laterally and results also in block of the lateral femoral cutaneous nerve of thigh.
The block of lateral cutaneous nerve of the thigh, in return, confers anesthesia to the lateral aspect of the thigh, which nicely complements the femoral nerve block.

49. Choice of local Anesthetic
The choice of the type and concentration of local anesthetic should be based on whether the block is planned for surgical anesthesia or pain management.
Long-acting local anesthetic should be avoided in ambulatory patients undergoing relatively minor procedures as ambulation is affected by prolonged motor block of the quadriceps muscle.

50. Choice of local Anesthetic

51. Block Dynamics and Perioperative Management
Minimal patient discomfort
However, many patients feel uncomfortable being exposed.
Sedation is necessary for the patient's comfort and acceptance. Midazolam 1-2 mg after patient is positioned and alfentanil µg just before the local infiltrations suffices for most patients.

52. Block Dynamics and Perioperative Management
A typical onset time for this block is minutes, depending on the type, concentration, and volume of local anesthetic used.
The first sign of onset of blockade is the loss of sensation of the skin over the medial aspect of the leg below the knee (saphenous nerve).
Weight bearing on the blocked side is impaired and this should be clearly explained the patient to prevent the risk of falls.

53. Complications Infection Hematoma Nerve injury Vascular puncture
Others (falls)

54. US Guided Ultrasound Landmarks:
The femoral artery and the femoral nerve. The nerve lies lateral or occasionally deep to the artery.

55. US Guided Transducer Type: 10 to15 MHz linear array
Transducer Position: The probe is located in the axial plane along the inguinal crease

56. US Guided
The femoral nerve appears as a hyperechoic flattened oval structure lateral to the femoral artery.

57. US Guided
The spread of the local anesthetic can be visualized in real time as hypoechoic solution surrounding the femoral nerve, and the needle tip is repositioned if required to ensure appropriate spread.

58. To summarize

59. Lumbar Plexus Block Indications: Hip, anterior thigh, and knee surgery
Landmarks: Iliac crest, spinous processes (midline)
Nerve stimulation: Twitch of the quadriceps muscle at mA current
Local anesthetic: mL
Complexity level: advanced

60. Femoral Nerve Block Indications: Anterior thigh and knee surgery
Landmarks: Femoral (inguinal) crease, femoral artery pulse
Nerve Stimulation: Twitch of the patella (quadriceps) at mA current
Local anesthetic: 20 mL
Complexity level: Basic

61. MCQs

62. MCQs All about lumbar plexus anatomy are true except:
Formed mainly by anterior rami of L1-L4
Receive contribution from S1-S2
Embedded in the psoas ms
Supplies the posterior aspect of the thigh.

63. MCQs The lumbar plexus Block landmark: At the PSIS At the Midline
At point 4 cm lateral to intersection between midline & intercrestal line
At L2-L4 vertebrae

64. MCQs Lumbar plexus Block Advanced technique High volumes are needed
Hemodynamic instability is a potential problem
Not used in anticoagulated patients

65. MCQs
The femoral nerve
Formed by the anterior divisions of the anterior rami of L2–L4.
Supply the adductors of the thigh
Supply the medial aspect of the lower leg via the saphenous nerve.
it is positioned immediately lateral and slightly deeper than the femoral artery

66. MCQs The femoral nerve block
The first sign of onset of blockade is the loss of sensation of the skin over the medial aspect of the leg below the knee (saphenous nerve).
Typical onset time for this block is minutes
Visible twitch of the quadriceps muscle) at MA current is the optimal response.
Carry high risk of postoperative falls.