Download Long Thoracic Nerve Injury

PALSIES OF SHOULDER GIRDLE NERVES
Accessory nerve injury
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trapezius is a major suspensory muscle of the shoulder girdle
critical in maintaining proper and efficient shoulder function by passively
supporting and actively stabilizing the scapula
paralysis results in chronic progressive pain and debility from disruption of
synchronous scapulohumeral rhythm.
major pitfall in early management is either failure to recognize or acknowledge
the injury or hoping that it will resolve with conservative treatment.
Variation of innervation of the trapezius alters clinical presentation and can make
diagnosis difficult.
Anatomy (M Leung, H Cleland PRS 2004)
Spinal Accessory nerve
 Cranial part arise from the cells of the nucleus ambiguus
 distributed principally to the pharyngeal and superior laryngeal branches of the
vagus.
 Spinal part
 arise from the motor cells in the lateral part of the anterior column of the gray
substance of the medulla spinalis as low as the fifth cervical nerve
 enters the skull through the foramen magnum, and is then directed to the
jugular foramen
 descends through the jugular foramen
 Travels into the neck between the internal carotid artery and the internal jugular
vein.
 spirals backward, crossing the internal jugular vein - runs backward in front of
the internal jugular vein in 2/3rd of cases, and behind in it 1/3rd.
 descends obliquely behind the posterior belly of Digastric and Stylohyoid to the
upper part of the Sternocleidomastoid
 Joined by fibers from the ventral ramus of C2, it gives off a motor branch to the
sternocleidomastoid muscle before passing deep(1/3rd ) to or through that
muscle(2/3rd ).
 emerges on the posterior border of the sternocleidomastoid muscle, variably
between the junction of the upper and middle thirds to halfway down, but
always in the upper half.
 passes obliquely across the floor of the posterior triangle, over the levator
scapulae, and just deep to the investing fascia and superficial to the prevertebral fascia.
 supplies motor fibers to the trapezius after entering deep to the anterior border,
classically described as at the junction of lower and middle thirds of the muscle,
or 2 to 5 cm from the acromium
Trapezius
 Overall, the muscle acts to elevate, retract, and rotate the scapula
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upper portion elevates the scapula and upwardly rotates the lateral angle, the
intermediate portion adducts and retracts it, and the inferior portion depresses and
rotates it downward
in the presence of trapezius paralysis, the entire shoulder is depressed and the
inferior border of the scapula rotates laterally
Landmarks
 Surface markings generally imprecise and variable with positional alterations
intraoperatively, especially in overweight patients.
 More importantly, the surface markings are unhelpful once the skin flaps have
been raised
 Erb’s point is the most commonly used.
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King and Mott’s Line
 horizontal line from the thyroid notch across the neck
 2 cm above the line delineates the nerve's emergence from the
sternocleidomastoid muscle and 2 cm below delineates the nerve's exit into the
trapezius
Salasche’s line
 line from the mastoid process to the angle of the mandible, and then drop a
perpendicular line at the midpoint.
 This line intersects with the posterior border of the sternocleidomastoid
muscle; the nerve emerges within a short distance above this point.
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Sheen’s line
 Identify transverse process of C2 and following a line from there to the
acromium
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Erbs point
 Initially described as surface marking of the upper trunk of the brachial
plexus
 two fingerbreadths above the clavicle and one fingerbreadth lateral to the
posterior edge of the sternocleidomastoid muscle
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great auricular point designates the point where the four branches (great
auricular, lesser occipital, transverse cervical, and suprascapular) of the
cervical plexus exit from the posterior border of the sternocleidomastoid
muscle
both points are now considered to be synonymous
great auricular nerve runs superficial to the investing fascia, on the surface of
the muscle
CN XI lies under the investing fascia
CN XI is usually about 1cm above Erb’s point and in a deeper plane
Aetiology
 Most commonly follows lymph node biopsy in posterior triangle (3-8% risk)
 Also
1. modified neck dissections
2. parotidectomies
3. carotid operations
4. facelifts.
Clinical
 Immediately after injury patients usually complain of pain over the muscle, a
heaviness of the arm, and depressed motor function characterized by inability to
lift the shoulder girdle and abduct the arm
 Arm becomes painful, probably because of traction on the brachial plexus.
 Late sequelae include shoulder droop, winging of medial scapula (transverse
trapezius fibers prevent this), atrophic trapezius and loss of abduction,
paresthesias, and adhesive capsulitis resulting in a frozen shoulder.
 Function does not improve or recover over time, although pain may subside.
 Occasionally the diagnosis is complicated by dual innervation of the trapezius
muscle from the cervical plexus. This additional nerve supply allows for some
muscle contraction (upper cervical part) and retains some motor function, thereby
confounding diagnosis.
 Pitfalls in diagnosis stem from dual nerve supply to the trapezius and the failure to
recognize that full-blown paralysis of the muscle may not occur even in the
presence of spinal accessory nerve discontinuity.
Management
Exposure
 under general anesthesia without the use of paralytic agents,
 patient is positioned supine and in reverse Trendelenburg position, with the
head turned to the contralateral side and the neck extended by elevating the
shoulders on a rolled towel
 Draping should permit adequate exposure of important landmarks, the earlobe, the
mandible, midline neck, upper anterior chest, and shoulder.
 Subplatysmal skin flaps are raised.
 The great auricular nerve is easily identified as it travels cranially on the investing
fascia over the sternocleidomastoid muscle, parallel and posterior to the
external jugular vein.
 intraoperative use of the electrode stimulator useful in densely fibrotic tissue.
Acute Injury
 best time to repair the nerve injury is at the time the injury is inflicted
 end-end repair
Subacute injury
 neurolysis if continuity maintained
 nerve graft may be required – sural nerve and great auricular nerve has been used.
Chronic injury
 Non-operative treatment for paralysis of the trapezius muscle, including
strengthening of the remaining thoracoscapular muscles, does not
satisfactorily compensate for the missing muscle function and gives
unsatisfactory overall clinical results.
 Indications for surgery
1. spontaneous trapezius palsy
2. when previous nerve surgery has failed,
3. when the time from the injury to treatment is over twenty months
1. Nerve transfer
 medial pectoral nerve has been used for proximal injury
 thoracodorsal nerve is another candidate
2. Eden-Lange lateral transfer
 Involves transfer of the levator scapulae insertion to the acromion and both
rhomboid muscles insertion to the infraspinatus fossa, having elevated the
infraspinatus from its fossa for at least half the width of the scapula.
 Attached by drill holes to the bone
 levator scapulae replaces the upper third of the trapezius, the rhomboideus
minor replaces the middle third, and the rhomboideus major replaces the
lower third
 some insert rhomboid minor into the supraspinatus fossa – reported more
closely approximates transverse part of trapezius
Long Thoracic Nerve Injury
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As one of the major scapular stabilizers, normal function of the serratus anterior is
critical in maintaining proper scapulohumeral rhythm during glenohumeral
movement, particularly arm elevation
serves to upwardly rotate and protract the scapula, keeping it closely applied
to the chest wall during shoulder motion
paralysis results in the classic angel wing deformity as the scapula is translated
medially and superiorly. The inferior angle rotates toward the midline and the
vertebral border of the scapula becomes prominent as it no longer is opposed to
the thoracic cage. The winging becomes more prominent as the patient attempts to
push forward against resistance.
Anatomy
Long thoracic Nerve
 Comprised of C5,C6 and C7
 C5 and C6 branches along with the dorsal scapular nerve, pass through the
substance of the scalenus medius muscle, whereas the seventh cervical root passes
anterior to it.
 nerve then travels beneath the brachial plexus and clavicle to pass over the first
rib.
Serratus Anterior
 Along with the levator scapulae, trapezius, and rhomboids, is a scapular rotator.
 It takes its origin from the first through ninth ribs.
 composed of three functional components.
 The upper component originates from the first and second ribs and inserts on the
superior angle of the scapula.
 middle component arises from the second, third, and fourth ribs, and inserts along
the anterior aspect of the medial scapular border.
 lower component is the largest and most powerful, originating from the fifth
through ninth ribs, and converging to insert on the inferior angle of the scapula.
 The main function of the serratus anterior is to protract and upwardly rotate the
scapula.
 is more active in forward flexion than pure abduction, as abduction requires some
retraction of the scapula.
 Without upward rotation and protraction of the scapula by the serratus anterior,
full glenohumeral elevation is not possible - abduction is limited to 110°.
Aetiology
 Iatrogenic complication following axillary dissection or after 1st rib excision
 Most are due to blunt chest trauma and most of these will resolve spontaneously
Clinical
 typically complain of weakness and pain about the shoulder.
 The pain is usually posterior in the serratus anterior antagonist muscles (rhomboid
major, rhomboid minor, levator scapulae) from spasm secondary to unopposed
contraction in the presence of serratus anterior weakness.
 Loss of scapular protraction and stabilization leads to difficulty with arm
elevation, especially with prolonged activity.
 Complaints of severe pain should raise the possibility of neuritis, such as
Parsonage-Turner syndrome.
Management
Nonsurgical management
 Generally more successful than in trapezius paralysis
 Includes
1. Activity modification
2. range of motion (ROM) to prevent contracture.
3. Strengthening of the remaining functional periscapular muscles helps maintain
shoulder function.
4. Various braces and orthotic devices - scapular cup type of brace, canvas
shoulder brace, or sling.
Surgical management
 25% of patients with serratus anterior paralysis will experience persistence of
scapular winging and will not respond to conservative treatment
Acute to subacute
 early nerve exploration with neurolysis, direct repair, or nerve grafting should be
considered in patients with penetrating trauma or iatrogenic injury to the nerve.
 thoracodorsal to long thoracic nerve transfer has been performed
Chronic
 some advocate waiting for 12-24 months
 3 groups of operations
1. scapulothoracic fusions
 regarded as salvage procedures after failure of other surgical techniques.
 Fusion of the scapula to the thorax eliminates scapular winging but also
eliminates scapulothoracic motion.
 Approximately 1/3 of total elevation is lost and complications such as
pneumothorax and pseudarthrosis have been reported to occur in as many
as 50% of patients
2. static stabilization procedures
 typically use a fascial graft or sling to tether the scapula to the vertebral
spinous processes or ribs
 out of favour as fascial grafts stretch over time
3. dynamic muscle transfers.
 have shown the best results for correction of scapular winging and
restoration of function
 provides dynamic control of the scapula and allows nearly normal
scapulothoracic motion.
Sternal head Pectoralis transfer
 preferred treatment is transfer of the sternal part of pectoralis major to
the inferior angle of the scapula, extended or reinforced with fascial
autograft.
 The sternal part of the pectoralis major has become popular because of its
substantial excursion, similar electromyographic activity, and power as the
serratus anterior, and because the orientation of its fibers approximates that
of the serratus anterior after transfer.
 Preservation of the clavicular head of the pectoralis major rather than use
of the entire tendon maintains internal rotation strength and provides a
cosmetically favorable breast contour.
 Postoperatively, the patient is placed in a custom scapulothoracic orthosis
and shoulder sling for 6 weeks. The orthosis has a pad that presses the
vertebral border of the scapula against the chest wall. After 6 weeks, the
brace is discontinued and progressive ROM and strengthening exercises
are started. No heavy lifting or a return to manual labor is allowed for 6
months.
15-cm skin incision is made beginning in the anterior axillary crease and extending in
the direction of the inferior angle of the scapula.
Axillary Nerve
Anatomy
 arises as one of the terminal branches of the posterior cord of the brachial plexus
(C5, C6)
 crosses the anteroinferior aspect of the subscapularis muscle where it then crosses
posteriorly through the quadrilateral space and divides into two major trunks.
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The posterior trunk gives a branch to the teres minor muscle and the posterior
deltoid muscle before terminating as the superior lateral brachial cutaneous
nerve.
The anterior trunk continues giving branches to supply the middle and anterior
deltoid muscle while travelling on the deep subfascial surface and within the
deltoid muscle
axillary nerve only is free for a short distance in the axilla and for the remainder of
its length, it is attached to the deltoid muscle by its numerous branches - renders it
susceptible to stretch injury and also explains the significant incidence of
infraclavicular brachial plexus injuries and avulsion of the axillary nerve from the
posterior cord of the brachial plexus after shoulder dislocation.
Aetiology
1. Glenohumeral Dislocation
 Incidence after dislocation ranges from 5% to 54%
 mechanism of injury in glenohumeral dislocations is one of traction and
compression as the axillary nerve becomes stretched across the humerus as it
dislocates anteriorly and inferiorly
2. Blunt trauma
 typically a direct blow to the anterolateral deltoid muscle such as that which
occurs during hockey collisions and when attempting to tackle an opposing
player
 50% will have had little or no recovery of deltoid muscle function
3. Quadrilateral Space Syndrome
 compression on the axillary nerve and posterior humeral circumflex artery
 characterized by poorly localized posterior shoulder pain, parethesias over the
lateral aspect of the shoulder and arm, and deltoid muscle weakness
 postulated to be secondary to abnormal fibrous bands and muscle hypertrophy
of the muscular boundaries of the space which cause static and/or dynamic
compression of the axillary nerve.
4. Iatrogenic
 Typically follows shoulder surgery- rotator cuff surgery, shoulder
arthroscopy, shoulder instability
Clinical
 weakness in shoulder elevation with abduction, accompanied by numbness and
paresthesias throughout the lateral arm.
Management
 rehabilitation program emphasizing active and passive ROM and strengthening of
the rotator cuff, deltoid, and periscapular musculature.
 Exploration indicated if there is no clinical or electrophysiologic recovery by 3 to
6 months after injury, especially if the mechanism of injury was consistent with
a nerve rupture (glenohumeral dislocation)
 Acute management consists of neurolysis, primary neurorraphy and nerve grafting
 For quadrangular space compression - posterior approach to the quadrilateral
space with release of the compressive fascia and fibrous bands around the axillary
nerve and posterior humeral circumflexed vessels.
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Nerve transfers – branch to triceps
Transfers
Trapezius transfer for shoulder abduction
o transfer of the clavicular and acromial insertion of the trapezius with or without fascia
lata to the deltoid insertion on the humerus to enhance abduction and reverse
subluxation.
L’Episcopo procedure for external rotation
o Transpose latissums dorsi (thoracodorasal) and teres major (lower subscapular nerve)
posterolaterally to improve external rotation
o Attach to bone or to rotator cuff
Pectoralis transfer for shoulder flexion
 transfer of the sternocostal part of the pectoralis major to the anterior deltoid for anterior flexion