1Lower Extremity Block A.Ghaleb,M.D. Associate professor Medical directorAcute and chronic Pain managementDept. of AnesthesiologyUAMS
2Lumbar plexusThe lumbar plexus is formed by the ventral rami of the first three lumbar nerves and the greater part of the fourthTwo major anastomosis involving the lumbar plexusone with a branch of the last thoracic nerveand another between the fourth and fifth lumbar nervesgive birth respectively to the :Infracostal nerveLumbosacral trunk which contributes to the sacral plexus.A.Ghaleb,M.D.
7Plexus locationThe lumbar plexus is located in a virtual space inside the Psoas major muscle. This space is limited medially by Psoas major insertions on the bodies of the vertebrae and their transverse processes and by the lumbar spine itself. The aponeurosis surrounding the plexus inside the Psoas major constitutes the anterior, posterior and lateral limits of this space.A.Ghaleb,M.D.
11Frequency of anesthesia in the three major nerves' territories Femoral nerveObturator nerveLateral femoral cutaneous nervePiffaut, 1996 (single injection)100%96%Rickwaert, 2000 (catheter)97.5%88%92%
12Indications Of L.P.B. Alone: It can be used for hip or knee surgery Combined with a sciatic nerve block:The lumbar plexus block can be used for most surgeries involving the lower limb
13Contraindications Vertebromeningeal infections. Lumbar vertebral trauma.Associated trauma or disorders making lateral positioning impossible (Femoral neck fracture is no contraindication to the lateral position).Coagulation abnormalities,In patients exhibiting severe lumbar scoliosis, the landmarks may be modified
14The patient lays on the side opposite to the block (thigh flexion: 30°; knee flexion: 90°) while the physician stands behind. An assistant facing the patient with hands on theupper thorax and thigh will help maintain correct position and identify thighmovements during neurostimulation.
15LandmarksAn horizontal line joining the top of the iliac crests at the L4-L5 level.A line joining the spinous processes of L3, L4 and L5.A line parallel to the line joining the spinous processes and passing over the posterior superior iliac spine.A line starting at the spinous process of L4 and reaching perpendicularly the line passing by the posterior superior iliac spine
16Puncture siteThe puncture site is located at the union of the lateral 1/3 and medial 2/3 of the line joining the spinous process of L4 to the line passing through the posterior superior iliac spine (approximately 40 mm lateral the spinous process of L4).This site differs from the classic one located at the junction of the line passing through the posterior superior iliac spine and the line joining the top of the iliac crests. Anatomical studies suggest that the location of the classic site is in fact too lateral. See the scanners above where we can see the puncture site and the anatomical cut .
18Puncture A septic Technique The needle is introduced perpendicularly to the skinStimulation intensity is adjusted between 1 and 2 ma for a 0.1-ms period of stimulation.The needle is inserted slowly through the muscles until it reaches the transverse process of L4. This contact is expected and provides a real safeguard.Anatomical studies have shown that the distance between the posterior edge of the costal process and the lumbar plexus is mm . The insertion depth of the needle is then noted. After adding 20 mm to the depth indicator, the needle is withdrawn and reoriented with a 5° angle in cephalic or caudal direction, thus avoiding the transverse process.The needle is inserted more deeply (without exceeding the additional 20 mm) until the required stimulation of the femoral nerve (ascension of the patella) can be observed. The intensity of the stimulation is then gradually reduced until the motor response disappears (0.5 ma).An aspiration test is then carried out to avoid vascular or spinal injection.
27Suitable responsesStimulation of Erector spinae or Quadratus lumborum muscles: This is a usual response to initial needle insertion. Poorly defined contractions are observed around the puncture site. Progression must continue. Stimulation of the femoral nerve: Contraction of the Quadriceps femoris muscle is noted. This is the ideal and sought-after response
28Unsuitable responsesStimulation of the obturator nerve: Contraction of the adductors, felt by palpation of the internal portion of the thigh, reveals that the needle is located too medially. The needle is withdrawn and reoriented laterally with a 5° angle.Stimulation causing thigh adduction and patella ascension. It may correspond to a stimulation of nerve near the spinal canal. This reveals that the needle is located too medially. The needle should then be withdrawn and reoriented with a 5° angle laterally.Thigh flexion on the pelvis is caused by stimulation of a motor branch to the Psoas major. Needle reorientation with a 5° angle toward cephalic or caudal direction should allow for stimulation of the femoral nerve at approximately the same depth.Sciatic nerve stimulation may happens if the puncture site is either too caudal or too medial (stimulation of the lumbosacral trunk). The needle must be reoriented with a 5° angle in both, cephalic and lateral direction
30Bundle-shaped, which parallels the Psoas major location
31ComplicationsVenous puncture: The lumbar vein may be punctured. The needle is then located too medially and must be reoriented with a 5° angle laterally.Ureter puncture: Needle tip is too deep. Kidney puncture : The needle is inserted too deep and too cephalic. Avoid puncture at the L3 level, particularly on the right side.Peritoneal puncture: Needle tip is too deep. Spinal or epidural puncture: The puncture site or the direction of the needle are too medial. Always aspirate before injecting slowly small quantities of anesthetic solution.Epidural extension of anesthesia : In this case, whether the catheter is located in the paravertebral space or in the Psoas compartment, the anesthetic solution reaches the epidural space. Analgesia is effective. The catheter can be left in placeIntravascular injection: Intravascular injection can be prevented with a proper test dose and divided injections.
32Fascia Iliaca Block Identify *ASIS *Pubic tubercle Connect & divide into thirds Junction of lateral 1/3rd & medial 2/3rd1 cm inferior to mark
34TechniqueInsert the needle at right angles to the skin until two clearly identifiable losses of resistance are felt, respectively at the crossing of the fascia lata then the fascia iliaca Single shot technique: inject the local anaesthetic through the lumen of the needle according the usual safety rules, then massage the swelling produced in order to favour the upward spread of the local anaesthetic Continuous infusion or iterative injection technique: when the tip of the needle is below the fascia iliaca, remove the obturator and introduce the catheter through the lumen in order to insert 2-3 cm of catheter at the inner aspect of the fascia iliaca. Set the connecting device and interpose an antibacterial filter before carefully dressing and fixing the catheter on the skin.
35Ilio inguinal block ASIS 2 cm inferior, 2 cm medial perpendicular advance needle through skindiscern a 'pop' or click as external oblique aponeurosis penetratedinject ml LA to block iliohypogastric nerveadvance needle a further cm to penetrate softer resistance of internal oblique muscleinject ml LA to block ilioinguinal nerve
36provides sensory anesthesia of : Femoral Nerve Blockprovides sensory anesthesia of :the anterior thighkneemedial aspect of the calf, ankle and foot
41The point of needle insertion is marked 1.5 cm lateral and 1.5 cm distal to the intersection ofthe inguinal ligament and the femoral artery
42Techniques NERVE STIMULATOR PARESTHESIAE LOSS OF RESISTANCE lies below two facial planes: the fascia lata and the fascia iliacusFIELD BLOCK
43"Three-in-One" Block INGUINAL PARAVASCULAR THREE-IN-ONE BLOCK A single injection of large volume within the neural "sheath" with the needle directed cephalad + pressure applied distal to the femoral nerve sheathBlock obturator and lateral femoral cutaneous nerves as well as the femoral nerve
47Sciatic Nerve BlockAnatomy The largest single nerve trunk of the body (a diameter about as large as the thumb (16-20 mm).It arises from the L4, L5, S1, S2, S3 spinal roots and exits the pelvis posteriorly through the greater sciatic foramen and runs laterally along the posterior surface of the ischium anterior to the piriformis muscle.The posterior cutaneous nerve of the thigh accompanies the sciatic nerve as it exits the greater sciatic foramen. The sciatic nerve has medial and lateral components which separate into the tibial and the common peroneal nerves in the superior aspect of the popliteal fossa.
48Classic Posterior Approach lateral (Sim's) position, with the operative side nondependent. The operative extremity is flexed 45 degrees at the hip and 90 degrees at the knee and rests against the dependent lower extremityThe posterior superior iliac spine (PSIS), greater trochanter, and sacral hiatus are identified and markedA line is drawn between the greater trochanter and PSIS . This line is bisected. A perpendicular is dropped 3-5 cm from the midpoint of this line to the point of needle insertion.
49Classic Posterior Approach The point of needle insertion should lie along a third line drawn between the greater trochanter and the sacral hiatus .6 inch nerve stimulator needle is advanced perpendicular to the skin. The nerve lies about 6-8 cm deepmotor response . Plantar flexion (downgoing toes) at less than 0.5 mA is the desired motor response and indicates placement of the needle near the medial part (tibial component) of the nerve
53Parasacral approch lateral recumbent position thigh slightly folded forming an angle of ° with the trunk.The knee flexed at 90°.A line is drawn between the postero-superior iliac spine and the ischial tuberositypuncture point is situated at 6 cm from the postero-superior iliac spine following this line
55PROCEDUREThe needle is inserted perpendicularly and progressed slowly,at approximately 6 cm-8 cm a motor response is obtained rarely more than 8 cmA bone contact may be the sacral ala or the iliac bone, superior and near the greater sciatic foramen. In this case needle should be withdrawn and reinserted inferior to the first point.Moreover this bone contact can be used as a depth test. Needle depth should be noted and it is recommended not to go more than 2 cm beyond this depth
56Popliteal Block Prone position Tendons of biceps femoris (lateral) and semitendinosus (medial)Popliteal creaseMidpoint between tendons at a point cm superior to popliteal crease .
60Lateral popliteal Anatomy In the mid thigh, the sciatic nerve more superficial lies medial to the biceps femorisIt is also distant from the femoral vesselsThe sciatic nerve is reached at a depth averaging 6 cm
61Position :The patient lies in supine. The ankle is posed on a pillow to raise the lower limb from the table.places one hand on the knee to move the leg to zero rotation for better exposure. With other hand insert the needle at the puncture siteLandmarks : A line is drawn from the posterior aspect of the great trochanter towards the knee, parallel to the femur. The puncture site is situated along this line, at mid thigh, from the knee to the great trochanter
62PearlsAnaesthetic injection after stimulation of the common peroneal nerve provides blockade of the latter within min followed by the blockade of the tibial nerve being effective within min. Anaesthetic injection after stimulation of the tibial nerve provides blockade of the two nerves in much less time.If no stimulation is obtained, it is recommended to re-insert a centimetre above or below the initial puncture site, instead of probing in vain.Hamstring Contractions indicate that the needle is beneath the sciatic nerve. Try and insert the needle one centimetre above
66Lateral Popliteal Block Lateral femoral condyleGroove between biceps femoris (posterior) and vastus lateralis (anterior)Horizontal plane to contact femur (approx 5 cm)Re-direct needle posteriorly at 30° angle
67Ankle Blockmedial malleolus Saphenous nerve 1cm anterior to malleolus, 1cm proximal to inter-malleolus line (skin crease) 5ml LATibial nerve Posterior to posterior tibial artery Contact bone and withdraw needle by 1mm 5ml LA