1. Peripheral Nerve Blocks using Nerve Stimulator
Dr.D.KANNAN. D.A., D.N.B.,
Consultant Anaesthesiologist,
Meenakshi Mission Hospital And Research Centre, Madurai.

2. Peripheral Nerve Blocks using Nerve Stimulator
Introduction
Nerve stimulator
Drugs and toxicity
Advantages of block
Anatomy
Nerve blocks
Femoral N
Obturator N
Sciatic N
Saphenous N
Ankle block

3. EQUIPMENTS Nerve Stimulator Unipolar needles of varying length
Flexible catheter
Electrode

4. Nerve Stimulator 1 Hz -Mixed nerve Current range from 0.1-5.0 mA
Pulse Frequency
1 Hz -Mixed nerve
2 Hz - Sensory nerve

5. Nerve Stimulator
The electrical current required to trigger muscle contractions correlates with the distance of the tip of the needle to the nerve.
That means that the closer the needle is to the nerve, the lower the electrical current that is required to induce contractions or sensory responses

6. Unipolar needle

7. Unipolar needles

8. Stimulation and Injection tecnique
Initial current mA
Frequency Hz
Threshold current mA
Aspiration test ml LA injected slowly
Increase the current to initial level
No stimulatory response - inject the remaining drug
Recurring response - May indicate intra vascular needle position

9. Drugs 2% Plain Lignocaine 3 mg / kg
2% Lignocaine with adrenaline 7 mg / kg of
0.5% Bupivacaine 2 mg / kg
o.75 % Ropivacaine mg / kg
Analgesic: % Bupivacaine, 0.2% Ropivacaine,
Opiods, Clonidine.

10. Local Anaesthetic Toxicity

11. Advantages of Block On Arrival block Preemptive analgesia
Post operative pain relief
Rescuing a risky patients
Less complications
Cost factor

12. Lower Limb innervations
The innervations of the leg is derived from the lumbar and sacral plexuses
Lumbar plexus formed by T12–L4
The main branches are
Lateral cutaneous N of thigh
Femoral N
Genitofemoral N
Obturator N

13. Lower Limb innervations
Lumbo sacral plexus formed by L4 –S5
Main branches are
Sciatic nerve
Posterior cutaneous nerve of thigh
Pudental nerve

14. Lumbosacral Plexus Lateral cutaneous N of thigh Femoral N
Genitofemoral N
Sciatic N
Obturator N
Pudental N

15. Distribution of Lumbo sacral plexus
Lateral cutaneous nerve of thigh
Femoral nerve
Sciatic nerve
Obturator nerve

16. Lower Limb Blocks Trans gluteal Femoral Nerve Block
Obturator Nerve Block
Lateral cutaneous Nerve Block
Trans gluteal
Sciatic Nerve Block
Popliteal
Saphenous Nerve Block
Ankle Block

17. Femoral Nerve Block
Indications
Operative procedures in areas supplying the femoral and lateral femoral cutaneous nerves
In combination with proximal sciatic nerve block, operative procedure on the whole leg.
Analgesia

18. Femoral Nerve Block Contraindications No particular
Side effects / complications
Vessel puncture (of the femoral vein or artery)

19. Femoral Nerve Block Anatomical landmarks Groin Femoral artery
Anterior superior iliac spine
Pubic tubercle
Inguinal ligament

20. Femoral Nerve Block Blockade technique Puncture site:
The patient lies on his back, his leg loosely abducted and turned to the outside.
Puncture site:
2cm caudad to the groin, 1 – 2 cm lateral to the femoral artery.

21. Femoral Nerve Block
Puncture direction: 30 ̊ – 40̊ cranial parallel to the artery.
Puncture depth: 2 – 4 cm.
Positive stimulatory response from the femoral nerve: Rectus muscle of the thigh (“dancing patella”).

22. What to do when?
Stimulation of the Sartorius muscle (medial contraction) occurs
Puncture direction usually too medial Retract the needle, and shift it slightly to the lateral.
Direct stimulation of the Sartorius muscle (rare):
Puncture direction is usually too lateral
Shift the needle slightly to the medial.
Femoral artery puncture:
Retract the needle Shift puncture direction to the lateral.

23. Potential errors and hazards
LA injection in the case of Sartorius muscle stimulation.
Intravascular injection

24. Obturator nerve block Indications
Suppression of the adductor reflex for the transurethral lateral bladder wall resection.
Treatment of adductor spasm.
Adjunct to the femoral nerve blocks for postoperative medial knee joint pain.
Analgesia.

25. Obturator nerve block Contraindications No particular
Side effect / complications
Vessel puncture (obturator artery or vein)

26. Anatomical landmarks Origin of adductor longus muscle Pubic tubercle
Femoral artery
Anterior superior iliac spine

27. Obturator nerve block Blockade technique
The patient is supine on his back, his leg is rotated outwardly and abducted.
Puncture site:
5 – 10 cm beneath the pubic tubercle directly lateral to the tendon origin of the adductor longus muscle.

28. Obturator nerve block
Puncture direction approx. 45 ̊ craniolateral pointing towards the anterior iliac spine.
Puncture depth: 4 – 6 cm.
Positive stimulatory response from adductor group.

29. What to do when? Persistent adductor spasm despite proper ONB
Perform additional femoral block
Note
The adductor reflux for TURP can reliably suppressed by separate Obturator Nerve block
Not by Femoral N block nor Spinal anaesthesia

30. Transgluteal sciatic nerve block
Indications
Operative procedure in areas supplying the sciatic nerve
In combination with psoas compartment block / femoral nerve block for operations on the whole leg
Analgesia

31. sciatic nerve block Contraindications No particular
Side effects / complications
Vessel puncture (inferior gluteal artery)

32. Transgluteal sciatic nerve block
Anatomical landmarks
Greater trochanter
Posterior superior iliac spine
Ischial tuberosity
Sacral hiatus
Puncture site

33. Transgluteal sciatic nerve block
Blockade technique
The patient is placed in the lateral recumbent position; hip flexed 45 ̊, knee flexed 70 ̊(“Stable recumbent position”)

34. Puncture site
4 – 5 cm mediocaudal on the mid-perpendicular lines between greater trochanter and posterior superior iliac spine; connecting line between the greater trochanter and sacral hiatus intersects the insertion point at the mid-perpendicular line.

35. 5 – 8 cm Puncture depth Positive stimulatory response
From the peroneal or tibial nerves:
Extensors or flexors of the foot or toes
Dosage
20-40 ml

36. What to do when? Contraction of the Gluteus maximus muscle
(= direct stimulation) occurs:
Continue to advance the needle until the typical response is elicited.
Stimulatory response from the ischiocrural muscle group:
LA injection possible Delayed onset of action

37. What to do when? Bone contact, No Stimulatory response:
Correct insertion direction to midline between greater trochanter and ischial tuberosity
Potential errors and hazards
LA injection upon stimulatory response from the gluteal muscles.

38. Popliteal sciatic nerve block
Indications
Operation procedure in the area supplying the sciatic nerve of the lower leg and foot
In combination with saphenous nerve block, operations on the whole lower extremity.
Analgesia.

39. Popliteal sciatic nerve block
Contraindications
Stent (relative)
Side effects / complications
Vessel puncture (popliteal artery/vein)

40. Popliteal sciatic nerve block
Anatomical landmarks
Popliteal fossa
Popliteal fold
Long head of the biceps femoris muscle
Medial and lateral epicondyle of the femur

41. Popliteal sciatic nerve block
Blockade technique
Patient is either in prone position or lying on his side, leg extended
Puncture site
8-12 cm above the fold of popliteal fossa at the medial edge of biceps femoris muscle.

42. Popliteal sciatic nerve block
Puncture depth
2-4 cm
Positive stimulatory response
From the Peroneal and Tibial nerve (extensors or flexors of the foot or toes)
Dosage: 30 – 40 ml

43. What to do when…? Femur contact occur:
Insertion too deep and too medial
Retract the needle Correct direction or insertion site to the lateral, reduce insertion depth.
Vessel puncture popliteal artery/vein:
Puncture too depth and too medial
Retract the needle Correct insertion direction to the lateral, reduce insertion depth.

44. Potential errors and hazards
Puncture site is too for caudad (popliteal fold):
It may be that the tibial (med.) and perpneal nerve (lat.) are separated so far apart that complete blocked cannot be achieved with a single LA injection at the two sciatic branches.

45. Saphenous nerve block Indications
Operative procedures in the area supplying the saphenous nerve.
In combination with distal sciatic nerve block for operations on the whole lower leg and foot.
Analgesia.

46. Saphenous nerve block No contraindications /side effects
Anatomical Landmarks
Petellar crest
Sartorius muscle
Vastus medialis muscle

47. Saphenous nerve block Blockade technique Puncture site:
Patient lies on his supine back with extended leg in neutral position, rotated slightly outwards.
Puncture site:
Approx. 2 – 4 cm cranial and medial of the upper patellar crest over the sartorius muscle. Puncture direction perpendicular through the muscle up to the subsartorial fatty tissue.

48. Saphenous nerve block Puncture depth: 3 – 5 cm.
Positive response include paresthesias on the medial lower leg at a pulse duration of 1.0 ms.
Dosage
10 – 15 ml LA

49. What to do When…?
Motor stimulatory response comes from the Vastus medialis muscle
Consider as positive Inject the drug
Alternative technique
Subcutaneous infiltration below the medial knee joint from the medial head of gastronemius muscle to the tibial tuberosity

50. Ankle Block
An ankle block is essentially a block of four branches of the sciatic nerve
Deep Peroneal N
Superficial Peroneal N
Tibial N
Sural N
one cutaneous branch of the femoral nerve
Saphenous N

51. Ankle Block Indications: Nerves: Local anesthetic: 6 mL per nerve
Surgery on foot and toes
Nerves:
Two deep nerves: Posterior tibial, deep peroneal
Three superficial nerves: superficial peroneal, sural, saphenous
Never use an epinephrine-containing local anesthetic
Local anesthetic: 6 mL per nerve

52. The deep peroneal nerve
Located immediately lateral to the tendon of extensor hallucis longus and medial to the extensor digitorum longus
The pulse of the anterior tibial artery (dorsalis pedis) can be felt at this location
The nerve is immediately lateral to the artery.

53. The posterior tibial nerve
Located just behind and distal to the medial malleolus.
The pulse of the posterior tibial artery can be felt at this location
The nerve is just posterior to the artery.

54. Superficial Peroneal, Sural and Saphenous Nerves.
Blockade of all three nerves is accomplished using a simple circumferential injection of local anesthetic subcutaneously.

55. Complications
Residual paresthesias due to an inadvertent intraneuronal injection.
Vascular puncture
Avoid puncturing the greater saphenous vein and Dorsalis pedis artery
Systemic toxicity is rare because of the distal location of the blockade.

56. Femoral N block

57. Obturator N block

58. Transgluteal sciatic N block

59. Popliteal sciatic N block

60. Saphenous N block

61. Thank you