The first brachial plexus blocks were performed by Halsted, in 1885, at
the Roosevelt Hospital in New York City. Later Crile, in 1902, described
an “open approach” to expose the plexus to the direct application of
cocaine. At the time, however, the clinical applicability of this approach
was limited because of the need for surgical exposure of the brachial
plexus. Percutaneous access to the brachial plexus was described in the
early 1900s. In 1925, Etienne1 reported the successful
blockade of the brachial plexus by inserting a needle at the level of the
cricothyroid membrane, halfway between the lateral border of the
sternocleidomastoid and the anterior border of the trapezius muscle after a
single injection through the area around the scalene muscles. This approach
is most likely the first clinically useful interscalene block technique.
Different approaches were then tried until Winnie, in
1970,2 described the percutaneous technique of
injecting local anesthetic into the groove between the anterior and
middle scalene muscles at the level of the cricoid cartilage. This approach
was the first consistently effective and technically suitable technique, and
it allowed wider applicability of interscalene brachial plexus block.
Winnie's approach was further modified, in line with numerous developments in
regional anesthesia, by the placement of a perineural catheter, for
Interscalene block is well suited for surgical procedures involving the
shoulder, including the lateral two thirds of the clavicle, proximal
humerus, and shoulder joint. Interscalene block can be used in the setting
of arm or forearm surgery, but incomplete blockade of the inferior trunk
often results in insufficient analgesia in the ulnar distribution. The
patient's positioning and comfort, the surgeon's preferences, and the
duration of surgery sometimes necessitate a combined general anesthesia. The
indications for single-shot and interscalene catheter are summarized in
Table 25-1. Single-Injection vs. The Choice of Technique: Interscalene Catheter According to Surgery. ||Download (.pdf)
Table 25-1. Single-Injection vs. The Choice of Technique: Interscalene Catheter According to Surgery.
|Type of Surgery||Type of Block Single-Injection||Catheter|
|Rotator cuff repair||+||+|
|Proximal humerus osteosynthesis||+||±|
|Clavicle osteosynthesis cervical block)||+ (± superficial cervical block)||–|
|Rotator cuff repair||+||+|
- Adequate control of pain is crucial after major open-shoulder surgery; early
rehabilitation is necessary for improving success.
- A major characteristic of the pain after shoulder surgery is its dynamic
component, which often interferes with rehabilitation.
- Up to 70% of patients report severe pain on movement after open major
shoulder surgery, which is more than after hysterectomy (60%),
gastrectomy, or thoracotomy (60%).4
- Major shoulder surgery entails massive nociceptive input from the richly
innervated joint and periarticular tissues, which produce continuous deep
somatic pain and reflex spasm of muscles.
- These structures are supplied by the same and adjacent spinal cord segments
supplying the site of surgery5; moreover, periarticular
structures exhibit not only C afferents, but also A-alpha and A-delta
afferents, the latter being poorly blocked by opioids, which explains the
relative inefficacy of opioids to control this type of postoperative pain.
Contraindications for interscalene brachial plexus block are rare.
Absolute contraindications include patient's refusal, local infection,
active bleeding in an anticoagulated patient, and proven allergy to local
anesthetic. Relative contraindications include chronic obstructive airway
disease, contralateral paresis of the phrenic or recurrent laryngeal nerves,
and previous neurologic deficit of the involved arm. The risks and benefits
of the chosen anesthetic technique should be discussed with the patient and
Understanding the relevant brachial plexus anatomy, ensuring precise
needle location within the plexus diffusion space, and injection of
appropriate volume and type of local anesthetic are fundamental for
achieving high success rates with brachial plexus anesthesia. The plexus is
formed by the ventral rami of the fifth to eighth cervical nerves and the
greater part of the ventral ramus of the first thoracic nerve
(Figure 25–1). In addition, small contributions may be made by
the fourth cervical and the second thoracic nerves. The anatomy becomes
complex because of the multiple connections to these ventral rami after they
emerge from between the middle and the anterior scalene muscles until they
end in the terminal nerves of the upper extremity. However, most of what
happens to these roots on their way to becoming peripheral nerves is not
clinically essential information to the anesthesiologist. Instead, broad
concepts such as the spatial arrangement of the trunks (superior, middle,
and inferior) and the muscular response elicited during electrostimulation
can be helpful to clinicians (Table 25–2).
Organization of the brachial plexus.
Table 25-2. Distribution of the Brachial Plexus ||Download (.pdf)
Table 25-2. Distribution of the Brachial Plexus
|Subclavius nerve||C4 through C6||Subclavius muscle|
|Dorsal scapular nerve||C4-C5||Rhomboid muscles and levator scapulae muscle|
|Long thoracic nerve||C5 through C7||Serratus anterior muscle|
|Suprascapular nerve||C4, C5, C6||Supraspinatus and infraspinatus muscles|
|Pectoralis nerves (medial and lateral)||C5 through T1||Pectoralis muscles|
|Subscapular nerves||C5, C6||Subscapular and teres major muscles|
|Thoracodorsal nerve||C6 through C8||Latissimus dorsi muscle|
|Axillary nerve||C5 and C6||Deltoid and teres minor muscles; skin of shoulder|
|Radial nerve||C5 through T1||Extensor muscles of the arm and forearm (triceps brachii,
extensor carpi radialis, extensor carpi ulnaris) and brachioradialis muscle; digital
extension and abductor pollicis muscle; skin over posterolateral surface of the arm|
|Musculocutaneous nerve||C5 through C7||Flexor muscles of the arm (biceps brachii, brachialis, coracobrachialis);
skin over lateral surface of the forearm |
|Median nerve||C6 through T1||Flexor muscles of the forearm (flexor carpi radialis, palmaris longus);
pronator quadratus, and pronator teres muscles; digital flexors (through the palmar interosseous nerve); skin over
anterolateral surface of the hand|
|Ulnar nerve||C8, T1||Flexor carpi ulnaris muscle, adductor pollicis muscle, and small digital muscles, skin over
medial surface of the hand|
The brachial plexus supplies all the motor and most of the sensory
functions of the shoulder except the cephalad cutaneous parts of the
shoulder, which are innervated by the supraclavicular nerves originating
from the lower part of the superficial cervical plexus (C3-4)
(Figure 25–2). They supply sensation to the shoulder above the
clavicle in addition to the first two intercostal spaces anteriorly.
Furthermore, they supply sensation to the posterior cervical triangle and
the upper thorax in this area as well as to the tip of the
The innervation of the skin over the shoulder and
Only three nerves of the brachial plexus have cutaneous representation in
the shoulder. The most proximal of these is the upper lateral brachial
cutaneous nerve, a branch of the axillary nerve that innervates the lateral
side of the shoulder and the skin overlying the deltoid muscle. The upper
medial side of the arm is innervated by both the medial brachial cutaneous
and the intercostobrachial cutaneous nerves. In the anterior portion of the
arm over the biceps muscle, the skin is innervated by the medial
antebrachial cutaneous nerve.6
Apart from the cutaneous nerve supply to the shoulder, the innervation of
the joint deserves special consideration. In general, a nerve crossing a
joint gives branches that innervate it. Therefore, the nerves supplying the
ligaments, capsule, and synovial membrane of the shoulder are fibers from
the axillary, suprascapular, subscapular, and musculocutaneous
nerves.7,8 The relative contributions of these nerves are
variable, and the supply from the musculocutaneus nerve may be very
small or completely absent. Anteriorly, the axillary nerve and suprascapular
nerve provide most of the nerve supply to the capsule and glenohumeral joint
(Figure 25–3). In some instances, the musculocutaneous nerve may
innervate the anterosuperior portion of the joint. In addition, the anterior
capsule may be supplied by either the subscapular nerves or the posterior
cord of the brachial plexus after piercing the subscapularis muscle.
Superiorly, primary contribution is from two branches of the suprascapular
nerve, one branch supplying the acromioclavicular joint and proceeding
anteriorly as far as the coracoid process and coracoacromial ligament and
the other branch reaching the posterior aspect of the joint. Other nerves
contributing to this region of the joint are the axillary nerve and
musculocutaneous nerve. Posteriorly, the main nerves are the suprascapular
nerve in the upper region and the axillary nerve in the lower region
The innervation of the anterior portion of the
shoulder. The axillary (1) and suprascapular (2) nerves form most of the
nerve supply to the capsule and the glenohumeral joint.
The posterior innervation of the shoulder joint. The
primary nerves are the suprascapular (1) and the axillary (2).
Inferiorly, the anterior portion is primarily supplied by the axillary
nerve, and the posterior portion is supplied by a combination of the
axillary nerve and lower ramifications of the suprascapular nerve.
- The following nerves should be anesthetized to achieve anesthesia for
arthroscopic surgery: supraclavicular, suprascapular, and axillary (radial)
- For open shoulder surgery, knowledge of the surgical approach is useful
because the surgical incision may also involve the territories of the median
cutaneous, intercostobrachial, and the median antebrachial cutaneous nerves.
The following surface anatomy landmarks are necessary for identifying
the interscalene groove:
1. Sternal head of the sternocleidomastoid muscle
2. Clavicular head of the sternocleidomastoid muscle
3. Upper border of the cricoid cartilage
These landmarks should always be marked with a pen (Figure 25–5).
The lateral modified technique (Borgeat). The needle
is inserted toward the plane of the interscalene space (dashed line) at an angle
between 45 and 60 degrees. The needle is inserted approximately 0.5 cm
under the level of the cricoid (C). SH, sternal head of the
sternocleidomastoid muscle; CH, clavicular head of the sternocleidomastoid
muscle. I, incisura jugularis sterni (sternal notch).
Equipment for Single-Shot Blockade
Standard regional anesthesia equipment for a single-shot blockade
consists of the following items (Figure 25–6).
- Marking pen, ruler
- Sterile gloves
- Peripheral nerve stimulator, surface electrode
- Disinfection solution and sterile gauze packs
- 2- to 5-cm, short-bevel, 22-gauge insulated stimulating needle
- Syringes with local anesthetic
Equipment for single-injection interscalene block.
Equipment for Continuous Blockade
Standard regional anesthesia equipment for a continuous nerve block
consists of the following items (Figure 25–7).
- Marking pen, ruler
- Peripheral nerve stimulator, surface electrode
- Disinfection solution, sterile gauze packs
- Sterile transparent drapes
- Syringes with local anesthetic for skin infiltration and block injection
- 25-mm, 25-gauge needle for skin infiltration at puncture point and for
- A set with stimulating needle for continuous nerve block and catheter
- Adhesive transparent tapes for securing the catheter
- Sterile gloves (cap, mask, and gown are optional)
Equipment for continuous interscalene block.