4 Nerve Stimulator 1 Hz -Mixed nerve Current range from 0.1-5.0 mA Pulse Frequency1 Hz -Mixed nerve2 Hz - Sensory nerve
5 Nerve StimulatorThe 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
8 Stimulation and Injection tecnique Initial current mAFrequency HzThreshold current mAAspiration test ml LA injected slowlyIncrease the current to initial levelNo stimulatory response - inject the remaining drugRecurring response - May indicate intra vascular needle position
11 Advantages of Block On Arrival block Preemptive analgesia Post operative pain reliefRescuing a risky patientsLess complicationsCost factor
12 Lower Limb innervations The innervations of the leg is derived from the lumbar and sacral plexusesLumbar plexus formed by T12–L4The main branches areLateral cutaneous N of thighFemoral NGenitofemoral NObturator N
13 Lower Limb innervations Lumbo sacral plexus formed by L4 –S5Main branches areSciatic nervePosterior cutaneous nerve of thighPudental nerve
14 Lumbosacral Plexus Lateral cutaneous N of thigh Femoral N Genitofemoral NSciatic NObturator NPudental N
15 Distribution of Lumbo sacral plexus Lateral cutaneous nerve of thighFemoral nerveSciatic nerveObturator nerve
17 Femoral Nerve BlockIndicationsOperative procedures in areas supplying the femoral and lateral femoral cutaneous nervesIn combination with proximal sciatic nerve block, operative procedure on the whole leg.Analgesia
18 Femoral Nerve Block Contraindications No particular Side effects / complicationsVessel puncture (of the femoral vein or artery)
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 BlockPuncture 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) occursPuncture 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 lateralShift 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 / complicationsVessel puncture (obturator artery or vein)
26 Anatomical landmarks Origin of adductor longus muscle Pubic tubercle Femoral arteryAnterior 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 blockPuncture 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 blockNoteThe adductor reflux for TURP can reliably suppressed by separate Obturator Nerve blockNot by Femoral N block nor Spinal anaesthesia
30 Transgluteal sciatic nerve block IndicationsOperative procedure in areas supplying the sciatic nerveIn combination with psoas compartment block / femoral nerve block for operations on the whole legAnalgesia
31 sciatic nerve block Contraindications No particular Side effects / complicationsVessel puncture (inferior gluteal artery)
32 Transgluteal sciatic nerve block Anatomical landmarksGreater trochanterPosterior superior iliac spineIschial tuberositySacral hiatusPuncture site
33 Transgluteal sciatic nerve block Blockade techniqueThe patient is placed in the lateral recumbent position; hip flexed 45 ̊, knee flexed 70 ̊(“Stable recumbent position”)
34 Puncture site4 – 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 toesDosage20-40 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 tuberosityPotential errors and hazardsLA injection upon stimulatory response from the gluteal muscles.
38 Popliteal sciatic nerve block IndicationsOperation procedure in the area supplying the sciatic nerve of the lower leg and footIn combination with saphenous nerve block, operations on the whole lower extremity.Analgesia.
40 Popliteal sciatic nerve block Anatomical landmarksPopliteal fossaPopliteal foldLong head of the biceps femoris muscleMedial and lateral epicondyle of the femur
41 Popliteal sciatic nerve block Blockade techniquePatient is either in prone position or lying on his side, leg extendedPuncture site8-12 cm above the fold of popliteal fossa at the medial edge of biceps femoris muscle.
42 Popliteal sciatic nerve block Puncture depth2-4 cmPositive stimulatory responseFrom 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 medialRetract the needle Correct direction or insertion site to the lateral, reduce insertion depth.Vessel puncture popliteal artery/vein:Puncture too depth and too medialRetract 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.
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.Dosage10 – 15 ml LA
49 What to do When…?Motor stimulatory response comes from the Vastus medialis muscleConsider as positive Inject the drugAlternative techniqueSubcutaneous infiltration below the medial knee joint from the medial head of gastronemius muscle to the tibial tuberosity
50 Ankle BlockAn ankle block is essentially a block of four branches of the sciatic nerveDeep Peroneal NSuperficial Peroneal NTibial NSural None cutaneous branch of the femoral nerveSaphenous N
51 Ankle Block Indications: Nerves: Local anesthetic: 6 mL per nerve Surgery on foot and toesNerves:Two deep nerves: Posterior tibial, deep peronealThree superficial nerves: superficial peroneal, sural, saphenousNever use an epinephrine-containing local anestheticLocal 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 longusThe pulse of the anterior tibial artery (dorsalis pedis) can be felt at this locationThe 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 locationThe 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 ComplicationsResidual paresthesias due to an inadvertent intraneuronal injection.Vascular punctureAvoid puncturing the greater saphenous vein and Dorsalis pedis arterySystemic toxicity is rare because of the distal location of the blockade.