Presentation on theme: "Brachial Plexus Block Above the Clavicle Edited by Dr. M Dorgham"— Presentation transcript:
1 Brachial Plexus Block Above the Clavicle Edited by Dr. M Dorgham Under supervision ofProff Dr. Amr Abdelfattah
2 Objectives Review the Anatomy of brachial plexus Neurostimulation guided approachesSonoanatomy and Ultrasound guidanceComplicationsAdvantages of ultrasound guidance
3 Anatomy of Brachial Plexus The brachial plexus is a network of nerve fibers , running from the spine, formed by the ventral rami of the lower four cervical and first thoracic nerve roots (C5-T1). It proceeds through the neck, the axilla (armpit region), and into the arm.The brachial plexus is responsible for cutaneous and muscular innervation of the entire upper limb, with two exceptions:The trapezius muscle innervated by the spinal accessory nerve (CN XI) andAn area of skin near the axilla innervated by the intercostobrachial nerve.
4 Anatomy of Brachial Plexus The brachial plexus is divided intoRootsTrunksDevisionsCordsBranches
5 The brachial plexus is divided into Roots,Trunks,Divisions,Cords, andBranches. There are five "terminal" branches and numerous other "pre-terminal" or "collateral" branches that leave the plexus at various points along its length.The five roots are the Anterior rami of the spinal nerves (C5 T1), after they have given off their segmental supply to the muscles of the neck.These roots merge to form three trunks:"superior" or "upper" (C5-C6)"middle" (C7)"inferior" or "lower" (C8-T1)Each trunk then splits in two, to form six divisions:anterior divisions of the upper, middle, and lower trunksposterior divisions of the upper, middle, and lower trunksThese six divisions will regroup to become the three cords. The cords are named by their position with respect to the axillary artery.The posterior cord is formed from the three posterior divisions of the trunks (C5-T1)The lateral cord is the anterior divisions from the upper and middle trunks (C5-C7)The medial cord is simply a continuation of the anterior division of the lower trunk (C8-T1)
7 Anatomy of Brachial Plexus NerveRootsMusclesCutaneousUpperTrunkNerve to subclaviusC5 C6SubclaviousSuprascapular nerveSupraspinatousInfraspinatous
8 Anatomy of Brachial Plexus NerveRootsMusclesCutaneousLateral cordLateral pectoral nerveC5 C6 C7Pectoralis Major By communication with Medial Pectoral NerveMusculocutaneous nerveCoracobrachialisBrachialisBiceps brachiiBecome the Lateral cutaneous nerve of forearmLateral root of median nerveFibres of Median nerve
9 Anatomy of Brachial Plexus NerveRootsMusclesCutaneousMedialcordMedial pectoral NrC8 T1Pectoralis majorPectoralis minorMedial root of median Nr.Fibres to median nerveportions of hand not served by ulnar or radialMedial cordMedial cutaneous nerve of armfront and medial skin of the armMedial cutaneous nerve of forearmmedial skin of the forearm
10 Anatomy of Brachial Plexus Medial cordUlnar Nr.C8 T1Flexor carpi ulnaristhe medial two bellies of flexor digitorum profundus,the intrinsic hand muscles except the thenar muscles.the two most medial lumbricalsthe skin of the medial side of the handmedial one and a half fingers on the palmar sidemedial two and a half fingers on the dorsal side
11 NerveRootsMusclesCutaneousPostcordUpper subscapular nerveC5 C6Sub scapilaris(upper part)Thoracodorsal Nr(Middle subscapular)C6 C7 C8Latismus DorsiPost cordLower scapular NrSubscapularis(lower part)Teres majorAxillary Nr.Ant Br: Deltoid & small area of overlying skinPost Br: Teres minor & Deltoid msPost Branch continues as upper Lateral cutaneous Nr of armRadial Nr.C5 C6 C7C8 T1Triceps brachiiSupinatorAnconeusBrachioradialisExtensors of forearmPosterior cutaneous nerve of arm
18 Superficial anatomyThe sternal head of the sternocleidomastoid muscle (1) is anterior to itsclavicular head (2), which forms the anterior borderof the posterior triangle of the neck.The accessory nerve (3) is superficial to the fascial floor of the posterior triangle of the neck and originates close to thelesser occipital nerve (4).The superficial cervical plexus (5) is superficial to the fascial floorof the posterior triangle of the neck and gives rise to thesupraclavicular nerves (6). The superficial cervical plexus originatesfrom C2 and supplies the ipsilateral skin of the neck, shoulder and occipital area with sensory fibers.The trapezius muscle (7) is innervated by the accessory nerve (3), and thenerve to levator scapulae innervates the levator scapulae muscle (8).
20 Deeper anatomyA view of the anatomy with the sternocleidomastoid muscle removed shows the position of theinternal jugular vein (1) (cut off here). Deep to the internal jugular vein is thethoracic duct (2) on the left side of the neck and adjacent to that theAnterior scalene muscle (3). Posterior to that is themiddle scalene muscle (4) and more posterior,the posterior scalene muscle (5). Posterior to the posterior scalene muscle is thelevator scapulae muscle (6) with thenerve to the levator scapulae muscle (7).The accessory nerve (8) as well as thetrapezius muscle (9) can be seen. Also note thevagus nerve (10), which is situated in close relationship to thecarotid artery (11), and thephrenic nerve (12), which is situated on the belly of the anterior scalene muscle (3). The brachial plexus (13) is situated between the anterior and middle scalene muscles. Thesuprascapular nerve (14) and thedorsal scapular nerve (15) (which innervates the rhomboid muscles) branches from thebrachial plexus. Note that thesubclavian artery (16) lies anterior to the brachial plexus.
23 “NERVE MAPPING”To facilitate proper anatomical orientation, the relative positions of the motor nerves in the posterior triangle of the neck canbe identified before the skin is penetrated“Nerve Mapping”Five nerves can be identified in the posterior triangle of the neck by percutaneousstimulation with 5 – 10 mA. Stimulating thephrenic nerve (1), just posterior to the clavicular head of the sternocleidomastoid muscle on the level of the cricoid cartilage (C6) causes unmistakable twitches of the diaphragm. Moving the needle one centimeter posteriorly will stimulate thebrachial plexus (2). This causes twitching of the biceps, triceps, major pectoral and/or the deltoid muscles. Posterior to the brachial plexus and posterior to the middle scalene muscle is thedorsal scapular nerve (3), which innervates the rhomboid muscles. Stimulation of this nerve causes the scapula and shoulder to move when the rhomboid muscles contract. This often causes confusion when stimulated and is a common cause of failed interscalene nerve blocks.levator scapulae muscle (4). Stimulating this nerve percutaneously will elevate the scapula and cause movements of the shoulder. More cephalad and higher up in the posterior triangle of the neck is theAccessory nerve (5), which innervates the trapezius muscle.
25 ANTERIOR APPROACH OR TRUE CONTINUOUS INTERSCALENE BLOCKNEEDLE PLACEMENT• The patient is placed in the supine position with the neck slightly flexed (to prevent the sternocleidomastoid muscle from covering the interscalene groove) and the head is slightly turned to the opposite side. The operator stands at the head of the bed, which is raised slightly to facilitate venous drainage so that venous congestion and accidental venous puncture are minimized.Feel for the interscalene groove with the middle and index fingers of the non-dominant hand (Figure 5)Split the fingers and apply light pressure with the middle finger. This causes the external jugular vein to become visible. The index finger applies traction to the skin for easy penetration by the needle.After appropriate skin infiltration with local anesthetic agent, the sheathed Tuohy needle (Arrow International, Reading, PA, USA) enters the skin halfway between the clavicle and the mastoid process just posterior to the posterior border on the sternocleidomastoid muscle.
26 needle approaches the brachial plexus and the nerve stimulator is set to 1 mA. Reduce the output of the nerve stimulator and look for brisk muscle twitches at approximately 0.5 mA (200 – 300 μs), which indicates penetration of the fascial sheath surrounding thebrachial plexus
27 POSTERIOR APPROACH (OR CONTINUOUS CERVICAL PARAVERTEBRAL BLOCK) The continuous cervical paravertebral block is ideal for relief of postoperative pain following shoulder surgery, especially arthroscopic shoulder surgery.This approach sometimes does not involve the nerves of the superficial cervical plexus and the skin around the shoulder area will therefore not be anesthetized.Although not yet evaluated by formal research, the experience of this author is that loss of resistance to air as well as nerve stimulation may be used for the placement in this block. If proven successful, this should make this block ideally suited for postoperative use, and when severely painful conditions such as fractures of the shoulder are present where nerve stimulation is not advisable or impractical.
28 AnatomyThe brachial plexus (1) is situated between the anterior (2) andmiddle (3) scalene muscles, while the vertebral artery (4) is guarded by the bony structures of the vertebrae.The posterior approach for ISB is antero-lateral to the trapezius muscle (5) and postero-medial to the levator scapulae muscle (6).
29 TECHNIQUE• The patient can be in the sitting or lateral decubitis position.After liberal skin and subcutaneous tissue injection of local anesthetic agent, the needle enters at the apex of the “V” formed by the trapezius and levator scapulaemuscles.• Attach the nerve stimulator and loss of resistance to air device to the needle and set the current output to 2 – 3 mA. Because the roots of the plexus have to a largeextent split into motor (anterior) and sensory (posterior) fibers here, more current is required to elicit a motor response.The needle is aimed medially and approximately 30 degrees caudate towards the suprasternal notch and advanced until the short transverse process of C6 isencountered.The needle is “walked off” this bony structure and there is a distinct change of resistance to air, which occurs simultaneously with muscle twitches in the armwhen the cervical paravertebral space is entered
30 AnatomyThe point of needle entry is in the apex of the “V” formed by thetrapezius muscle posterior and the levator scapulae muscle anterior –the “B”-spot
31 Surface anatomyNeedle entry should be at the level of C6 and just antero-lateral to the trapezius muscle and postero-medial to the levator scapulae muscle in the apex of the “V” formed by these two muscles.
32 Needle placementThe nerve stimulator is clipped to the needle and a loss-of-resistance to air device is placed on the needle. The needle is directed , anteriorly and caudad, aiming for the suprasternal notch.The needle is carefully “walked off” the transverse process of C6 and loss ofresistance to air and muscle twitches of the shoulder girdle appearsimultaneously.
33 Practical pointsThe anterior approach to the interscalene space is probably best suited for “open” shoulder surgery, while the posterior approach is ideal for arthroscopic surgery.The posterior approach provides less motor block than the anterior approach, but does not usually provide anesthesia of the skin around the shoulder joint.Horner’s syndrome almost always accompanies the posterior approach,The loss of resistance to air technique for placement of the cervical paravertebral block (posterior approach to ISB) may makes it ideally suited for postoperative placement or other instances where nerve stimulation is undesirable or painful.Protect the ulnar nerve (at the elbow) and radial nerve (mid-humeral area) while the arm is insensitive.Prevent traction injury to the brachial plexus by proper positioning on the operating table during surgery and by using a properly fitted sling in the ambulatorypatient.
34 Inadvertent epidural or subarachnoid injection is a potentially serious complication resulting from incorrect needle placement.Vertebral artery injection, this can result in convulsions and loss of consciousness.Phrenic nerve block is frequently produced, this complication precludes bilateral use of this technique.Recurrent laryngeal, vagus, and cervical sympathetic nerves are sometimes blocked.Pneumothorax is rare but can happen with deep placement of the needle and in unskilled hands.
36 The patient is in semi-sitting supine position with the head facing away from the side to be anesthetized.The premedication of an adult, average size patient typically consists of2-4 mg of midazolam;250mcg -500mcg of alfentanyl administered just before insertion of the needleTIP: Visualization of the brachial plexus in the interscalene grove can be challenging in patients who are tense, moving or exhibit guarding. Proper sedation can go a long way toward obtaining quality images.
37 The ultrasound probe (10-12MHz) is applied in the axial oblique plane closer to the midline and angled to first visualize the carotid artery
38 Note the position of the internal jugular vein (IJ) as the pressure on the ultrasound probe is lightened. The internal jugular vein is positioned slightly superficially and lateral to the carotid artery. Changing the pressure on the probe causes the IJ to open and close.
39 The ultrasound probe is then moved slightly laterally to visualize the brachial plexus in the interscalene grove between anterior and middle scalene muscles.The roots/trunks (N) of the brachial plexus are seen stacked between the scalene muscles usually as round, hypoechoic structures
40 Sliding or angling the ultrasound probe slightly more inferior allows visualization in the low-interscalene position in which the brachial plexus is positioned in proximity to the subclavian artery
41 After the brachial plexus is identified on the image, a 50 mm (max) stimulating needle is inserted perpendicular to the long axis of the ultrasound probe. The needle is inserted at the point on the probe that corresponds to the location of the brachial plexus on the screenThe needle insertion results in shadowing of the ultrasound image which indicates the path of the needleTIP: Make sure to estimate the exact depth of the brachial plexus (typically cm) before inserting the needle. The needle should never be inserted deeper than the depth indicated on the ultrasound image.
42 Injection of local anesthetic is made with monitoring of the dispersion of the injectate. If the injectate does not appear to fill the lower compartment of the interscalene space, the needle is slightly advanced (0.5-1cm) and additional injection is made at a slightly greater depth (0.5-1cm deeper).Local anesthetic is injected slowly and with frequent aspirations, while avoiding excessive injection pressures (<20 psi).Thirty to forty ml of local anesthetic is more than adequate for reliable blockade of the brachial plexus.Typical indications for this block are surgery on the shoulder, lateral clavicle, acromioclavicular joint, proximal humerus and elbow (with low interscalene block).
49 POSITIONING• The patient is placed supine• The patient’s head is turned toward the contralateral side• The operator is positioned on the ipsilateral side• The ultrasound machine should be placed on the contralateral sideSONOANATOMY.The subclavian artery appears hypoechoic and pulsatile and the individual nerves as hypoechoic small circles.It is very important to identify the pleura while performing this block so as to avoid pneumothorax.The first rib acts as a backstop to prevent pleural puncture, which means that the needle tip is in the same plane
53 The major advantage of the supraclavicular approach is that the nerves are very tightly packed, so that the onset is fast and the blockade deep, leading to this technique being nicknamed “the spinal of the arm”.Ultrasound guidance, the pleura can be visualized, and as long as proper technique is used, i.e. if the needle, and especially the needle tip, is visualized at all times, pneumothorax should not occur.Typical Indication : For surgeries below the mid-humerus level.It will not diffuse to the lower roots of the cervical plexus, and thus will not block the upper aspect of the shoulder.Twenty to Forty mls local anaesthetic is adequate for reliable block
54 Possible Complications Peripheral Nerve InjuryMost nerve injury presents as residual paresthesia, hand or forearm hypoesthesia, and rarely as permanent ParesisThe overall incidence of long-term nerve injury ranges between 0.02% and 0.4%Vascular InjuryThe risk of hematoma immediately after brachial plexus techniques is small (0.001 to 0.02%)Muscle InjuryMyonecrosis from local anesthetics at concentrations typically achieved at the site of injection is well proven and characteristic of all local anesthetics, with bupivacaine producing the most intense effect. Because damage is dose related, continuouslocal anesthetic administration may worsen injury.
55 Hemidiaphramatic Paresis The proximity of the phrenic nerve to the interscalene groove frequently leads to unintended local anesthetic block and resultant diaphragmatic dysfunction.The incidence of hemidiaphragmatic paresis (HDP) is % after interscalene brachial plexus blockPneumothoraxThe reported incidence of pneumothorax after supraclavicular block is 0.5% to 6.1%Intravascular Injectionlocal anesthetic injected directly into the vertebral or carotid artery, or retrograde flow of local anesthetic via the subclavian artery, may proceed directly to the brain.
56 Subarachnoid or Epidural Injection. Interscalene brachial plexus block has been linked to unintended subarachnoid block and to cervical or thoracic epidural block.Cervical Sympathetic Chain.Excessive local anesthetic spread can also affect the cervical sympathetic chain, causing the patient to manifest Horner’s syndrome.with20% to 90% incidenceRecurrent Laryngeal Nerve.Hoarseness may transpire after interscalene block or after 1.3% of supraclavicular blocks
57 Advantages of Ultrasound Guidance Ultrasound guidance with real-time needle visualization in relation to anatomic structures and target nerves makes regional anesthesia safer and more successful.With ultrasound guidance in experienced hands, brachial plexus blockade can lead toDecreased block performance and onset time,Increased success rate andDecreased rate of complications.These advantages result in increased operating room efficiency, as well as increased patient satisfaction.
59 The infraclavicular block is a blockade of the brachial plexus below the level of the clavicle and in the proximity of the coracoid process.This block is uniquely well-suited for hand, wrist, elbow, and distal arm surgery. It also provides excellent analgesia for an arm tourniquet.As opposed to a supraclavicular block, an infraclavicular block isnot a good choice for shoulder surgery.
60 Anatomic structures of importance Anatomic structures of importance. Pectoralis muscle (shown cut to expose brachial plexus)clavicle (removed)coracoid processhumerusbrachial plexussubclavian/axillary artery and veinThe boundaries of the infraclavicular fossa are the pectoralis minor and major muscles anteriorly, ribs medially, clavicle and the coracoid process superiorly, and humerus laterally. At this location, the brachial plexus is composed of cords. The sheath surrounding the plexus is delicate. It contains the subclavian/axillary artery and vein. Axillary and musculocutanous nerves leave the sheath at or before the coracoid process in 50% of patients. Consequently, the deltoid and biceps twitches should not be accepted as reliable signs of brachial plexus identification.
61 The patient is in the supine position with the head facing away from the side to be blocked. The anesthesiologist also stands opposite to the side to be blocked to assume an ergonomic position during the block performance.It is best to keep the arm abducted and flexed in the elbow to keep the relationship of the landmarks to the brachial plexus constant.Attention should be paid when the arm is supported at the wrist to allow clear unobstructed detection of the twitches of the hand
62 Surface LandmarksThe following surface anatomy landmarks are useful in identifying the estimated site for an infraclavicular block:Sternoclavicular jointMedial end of the clavicleCoracoid processAcromioclavicular jointHead of the humerusAnatomic LandmarksLandmarks for the infraclavicular block include:Coracoid ProcessMedial clavicular headMidpoint of line connecting 1 and 2 and 3cm caudalThe needle insertion site is marked approximately 3cm caudal to the midpoint of the line connecting points 1 and 2.
63 TIP: Palpation of the bony prominence just medial to the shoulder, while the arm is elevated and lowered, identifies the coracoid process. As the arm is lowered, the coracoid process meets the fingers of the palpating hand. This maneuver should be used to identify the coracoid process in each patient planned for an infraclavicular block
64 Needle insertionA 10-cm long, 22-gauge insulated needle, attached to a nerve stimulator, isInserted at a 45-degree angle to the skin andAdvanced parallel to the line connecting the medial clavicular head with the coracoid process.The nerve stimulator is initially set to deliver 1.5 mA. A local twitch of the pectoralis muscle is typically elicited as the needle is advanced beyond the subcutanous tissue. Once the pectoralis twitches disappear, the needle advancement should be slow and methodical while looking for the twitch of the brachial plexus
65 TIPS:When the pectoralis twitch is absent despite appropriately deep needle insertion, the landmarks should be checked as the needle is most likely inserted too cranially (underneath the clavicle).The bevel of the needle should be facing down to facilitate nerve stimulation and reduce the risk of vascular puncture (subclavian or axillary artery and vein).Brachial plexus stimulation is typically obtained at a depth of 5 to 8 cm.Twitches from the biceps or deltoid muscles should not be accepted, since the musculocutaneous and axillary nerve, respectively, may depart the brachial sheath before the caracoid process