Transcript brachial plexus
Brachial Plexus Block Above the Clavicle
Edited by Dr. M Dorgham Under supervision of Proff Dr. Amr Abdelfattah
Objectives
Review the Anatomy of brachial plexus Neurostimulation guided approaches Sonoanatomy and Ultrasound guidance Complications Advantages of ultrasound guidance
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) and An area of skin near the axilla innervated by the intercostobrachial nerve.
Roots Trunks Devisions Cords Branches
Anatomy of Brachial Plexus
The brachial plexus is divided into
Roots Roots
Anatomy of Brachial Plexus
Nerve Roots Muscles Cutaneous Dorsal scapular nerve C5 Rhomboid Levator scapulae Long thoracic nerve C5 C6 C7 Serratus anterior
Anatomy of Brachial Plexus
Nerve Roots Muscles Cutaneous Upper Trunk Upper Trunk Nerve to subclavius C5 C6 Suprascapular nerve C5 C6 Subclavious Supraspinatous Infraspinatous
Anatomy of Brachial Plexus
Nerve Roots Muscles Cutaneous Lateral cord Lateral pectoral nerve Lateral cord Lateral root of median nerve C5 C6 C7 Pectoralis Major By communication with Medial Pectoral Nerve Lateral cord Musculocutaneous nerve C5 C6 C7 Coracobrachialis Brachialis Biceps brachii Become the Lateral cutaneous nerve of forearm C5 C6 C7 Fibres of Median nerve
Anatomy of Brachial Plexus
Nerve Medial cord Medial pectoral Nr Medial cord Medial root of median Nr.
Roots C8 T1 C8 T1 Medial cord Medial cutaneous nerve of arm Medial cord Medial cutaneous nerve of forearm C8 T1 C8 T1 Muscles Cutaneous Pectoralis major Pectoralis minor Fibres to median nerve portions of hand not served by ulnar or radial front and medial skin of the arm medial skin of the forearm
Medial cord
Anatomy of Brachial Plexus
Ulnar Nr.
C8 T1 1. Flexor carpi ulnaris 2. the medial two bellies of flexor digitorum profundus, the skin of the medial side of the hand medial one and a half fingers on the palmar side 3. the intrinsic hand muscles except the thenar muscles. medial two and a half fingers on the dorsal side 4. the two most medial lumbricals
Post cord Post cord Post cord Post cord Post cord Nerve Roots Muscles Cutaneous Upper subscapular nerve Thoracodorsal Nr (Middle subscapular) Lower scapular Nr C5 C6 Sub scapilaris (upper part) C6 C7 C8 Latismus Dorsi Axillary Nr.
Radial Nr.
C5 C6 C5 C6 C5 C6 C7 C8 T1 Subscapularis (lower part) Teres major Ant Br: Deltoid & small area of overlying skin Post Br: Teres minor & Deltoid ms Triceps brachii Supinator Anconeus Brachioradialis Extensors of forearm Post Branch continues as upper Lateral cutaneous Nr of arm Posterior cutaneous nerve of arm
INTERSCALENE BLOCK ANTERIOR APPROACH
Superficial anatomy
Superficial anatomy
The sternal head of the sternocleidomastoid muscle (1) is anterior to its clavicular head (2), which forms the anterior border of 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 the lesser occipital nerve (4). The superficial cervical plexus (5) is superficial to the fascial floor of the posterior triangle of the neck and gives rise to the supraclavicular nerves (6). The superficial cervical plexus originates from 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 the nerve to levator scapulae innervates the levator scapulae muscle (8).
Deep anatomy
Deeper anatomy
A view of the anatomy with the sternocleidomastoid muscle removed shows the position of the internal jugular vein (1) (cut off here). Deep to the internal jugular vein is the thoracic duct (2) on the left side of the neck and adjacent to that the Anterior scalene muscle (3). Posterior to that is the middle scalene muscle (4) and more posterior, the posterior scalene muscle (5). Posterior to the posterior scalene muscle is the levator scapulae muscle (6) with the nerve to the levator scapulae muscle (7). The accessory nerve (8) as well as the trapezius muscle (9) can be seen. Also note the vagus nerve (10), which is situated in close relationship to the carotid artery (11), and the phrenic 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. The suprascapular nerve (14) and the dorsal scapular nerve (15) (which innervates the rhomboid muscles) branches from the brachial plexus. Note that the subclavian artery (16) lies anterior to the brachial plexus.
Surface anatomy
1 = Phrenic nerve 2 = Brachial plexus 3 = Dorsal scapular nerve (to rhomboid muscles) 4 = Nerve to levator scapulae
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.
Anatomy
The 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).
Anatomy
The point of needle entry is in the apex of the “V” formed by the trapezius muscle posterior and the levator scapulae muscle anterior – the “B”-spot
Surface anatomy
Needle 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.
Needle placement
The 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 of resistance to air and muscle twitches of the shoulder girdle appear simultaneously.
Ultrasound guided Interscalene Brachial plexus block
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 of 2-4 mg of midazolam; 250mcg -500mcg of alfentanyl administered just before insertion of the needle TIP: 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.
The ultrasound probe (10-12MHz) is applied in the axial oblique plane closer to the midline and angled to first visualize the carotid artery
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.
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
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
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 screen The needle insertion results in shadowing of the ultrasound image which indicates the path of the needle TIP:
Make sure to estimate the exact depth of the brachial plexus (typically 0.5-1.5 cm) before inserting the needle. The needle should never be inserted deeper than the depth indicated on the ultrasound image.
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).
Supraclavicular Brachial Plexus Block
The trunks divide behind the clavicle into anterior and posterior divisions, which separate the innervation of the ventral and dorsal halves of the upper limb.
Classic Kulenkampff technique
In 1988 Brown described the plumb-bob technique
Ultrasound guided Supraclavicular Brachial Plexus Block
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 side
SONOANATOMY.
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
the
"chimney" effect
as local anesthetic is forced to spread up between the anterior and middle scalene muscles, unable to go down because the first rib is in the way.
Pre injection Post injection
•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
Possible Complications
•
Peripheral Nerve Injury
Most nerve injury presents as residual paresthesia, hand or forearm hypoesthesia, and rarely as permanent Paresis The overall incidence of long-term nerve injury ranges between 0.02% and 0.4% •
Vascular Injury
The risk of hematoma immediately after brachial plexus techniques is small (0.001 to 0.02%) •
Muscle Injury
Myonecrosis 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, continuous local anesthetic administration may worsen injury.
•
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 50-100% after interscalene brachial plexus block •
Pneumothorax
The reported incidence of pneumothorax after supraclavicular block is 0.5% to 6.1% •
Intravascular Injection
local 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.
•
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% incidence •
Recurrent Laryngeal Nerve
.
•
Hoarseness may transpire
after interscalene block or after 1.3% of supraclavicular blocks
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 to •Decreased block performance and onset time, •Increased success rate and •Decreased rate of complications. These advantages result in increased operating room efficiency, as well as increased patient satisfaction.
Thank You
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 is
not a good choice for shoulder surgery.
Anatomic structures of importance. Pectoralis muscle (shown cut to expose brachial plexus) clavicle (removed) coracoid process humerus brachial plexus subclavian/axillary artery and vein The 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.
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
Surface Landmarks
The following surface anatomy landmarks are useful in identifying the estimated site for an infraclavicular block: 1.Sternoclavicular joint 2.Medial end of the clavicle 3.Coracoid process 4.Acromioclavicular joint 5.Head of the humerus
Anatomic Landmarks
Landmarks for the infraclavicular block include: 1.Coracoid Process 2.Medial clavicular head 3.Midpoint of line connecting 1 and 2 and 3cm caudal The needle insertion site is marked approximately 3cm caudal to the midpoint of the line connecting points 1 and 2.
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
Needle insertion
A 10-cm long, 22-gauge insulated needle, attached to a nerve stimulator, is Inserted at a to the skin and
45-degree angle
Advanced parallel to the line connecting the
medial clavicular head coracoid process
.
with the
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
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