Several reports on the results of surgical treatment of axil-lary nerve lesions have been pub-lished.1-4 A thorough understanding of the etiology, diagnosis, and treat-ment of axillary n
Trang 1Axillary nerve lesions are not
com-monly diagnosed Although most
such injuries respond to
nonopera-tive measures, surgical treatment is
warranted in selected cases With
ad-vances in microsurgery, increased
awareness of the potential for
treat-ment of brachial plexus injuries, and
the greater focus on shoulder
disor-ders in the past decade, complex
reconstructive procedures on the
shoulder are now more common
Accurate knowledge of axillary nerve
anatomy and function is paramount
to avoid complications after such
procedures Several reports on the
results of surgical treatment of
axil-lary nerve lesions have been
pub-lished.1-4 A thorough understanding
of the etiology, diagnosis, and
treat-ment of axillary nerve lesions not
only aids in the avoidance of injury to
the nerve during surgical procedures
but also promotes early recognition
and treatment
Anatomy
The axillary nerve is a terminal branch of the posterior cord of the brachial plexus and derives from the ventral rami of the fifth and sixth cranial nerves The first portion of the axillary nerve lies lateral to the radial nerve, posterior to the axil-lary artery, and anterior to the sub-scapularis muscle It runs obliquely across the inferolateral border of the subscapularis, crossing 3 to 5 mm from its musculotendinous junction
The axillary nerve then enters the quadrilateral space accompanied by the posterior humeral circumflex ar-tery The boundaries of the quadri-lateral space are the subscapularis anteriorly, the teres major and latis-simus dorsi inferiorly, the long head
of the triceps medially, and the humerus laterally When the shoul-der is viewed from its posterior aspect, the teres minor forms the
superior border of the quadrilateral space The nerve lies in intimate contact with the inferior joint cap-sule as it passes through the quadri-lateral space (Fig 1) When the nerve exits the space, it continues to the posterior aspect of the humeral neck and divides into anterior and posterior branches
The anterior portion of the nerve continues to circle around the surgi-cal neck of the humerus, traveling deep to the deltoid toward the ante-rior border of the muscle Along the way, the nerve sends branches
to innervate the middle and ante-rior portions of the deltoid The position of the anterior trunk is commonly reported to lie 4 to 7 cm inferior to the anterolateral corner
of the acromion.5
The posterior trunk innervates both the teres minor and the poste-rior portion of the deltoid A branch
to the teres minor usually arises within or just distal to the quadrilat-eral space and enters the posterior
or inferior aspect of the teres minor muscle A terminal branch of the
Dr Steinmann is Assistant Professor, De-partment of Orthopaedic Surgery, Mayo Clinic, Rochester, Minn Dr Moran is Chief Resident, Department of Orthopaedic Surgery, National Naval Medical Center, Bethesda, Md Reprint requests: Dr Steinmann, Mayo Clinic,
200 First Street SW, Rochester MN 55905 Copyright 2001 by the American Academy of Orthopaedic Surgeons.
Abstract
Axillary nerve injury is infrequently diagnosed but is not a rare occurrence.
Injury to the nerve may result from a traction force or blunt trauma applied to
the shoulder The most common zone of injury is just proximal to the
quadri-lateral space Atraumatic causes of neuropathy include brachial neuritis and
quadrilateral space syndrome The vast majority of patients recover with
non-operative treatment Baseline electromyographic and nerve conduction studies
should be obtained within 4 weeks after injury, with a follow-up evaluation at
12 weeks If no clinical or electromyographic improvement is noted, surgery
may be appropriate The results of operative repair are best if surgery is
per-formed within 3 to 6 months from the injury Surgical options include
neuroly-sis, nerve grafting, and neurotization The results of repair of axillary nerve
injuries have been good compared with treatment of other peripheral nerve
lesions, due to the monofascicular composition of the nerve and the relatively
short distance between the zone of injury and the motor end-plate.
J Am Acad Orthop Surg 2001;9:328-335
Scott P Steinmann, MD, and Elizabeth A Moran, MD
Trang 2posterior trunk forms the superior
lateral cutaneous nerve
There are several common
ana-tomic variations of the course of the
axillary nerve In as many as 20%
of persons, the axillary nerve
origi-nates from the posterior division of
the upper trunk of the plexus
Oc-casionally, the seventh cervical root
contributes to the axillary nerve
The axillary nerve may also give
rise to the inferior subscapular
nerve, which innervates both the
subscapularis and the teres major
The internal topography of the
fascicular groups has been studied
by Aszmann and Dellon.6 The nerve
in the axilla is monofascicular, but as
the nerve enters the quadrilateral space there are three distinct groups
of fascicles: the motor groups to the deltoid and teres minor and the sen-sory group of the superior lateral cutaneous nerve These fascicles are discrete entities within the posterior cord The deltoid fascicles are al-ways found in a superolateral posi-tion; those of the teres minor and superior lateral cutaneous nerve are located inferomedially
Etiology
Most axillary nerve injuries present
as part of a combined brachial
plexus injury In reported studies, infraclavicular isolated axillary nerve injury occurred in only 0.3% to 6% of brachial plexus injuries.3,7 Such infra-clavicular injuries have been found
to have a greater likelihood of spon-taneous recovery of function than supraclavicular lesions.8
Injury to the axillary nerve most commonly follows closed trauma involving a traction injury to the shoulder, usually with associated dislocation or fracture (Table 1) Some patients may have an occult, subclinical axillary nerve lesion that
is evidenced by the findings from the electromyographic and nerve conduction study (EMG/NCS) but that is masked by overlying dis-comfort from an associated fracture
or dislocation.9 Blunt trauma to the anterior lateral aspect of the shoul-der has also been noted to cause ax-illary neuropathy The mechanism of injury in such cases is considered to
be a compressive force to the nerve
as it travels on the deep surface of the deltoid muscle.10 Occasionally, the patient presents after an injury with
a mixed brachial plexus palsy affect-ing primarily the proximal shoul-der girdle muscles with partial arm
or hand palsy With observation and nonoperative treatment, sponta-neous recovery of the forearm neu-ropathy usually occurs When there
is incomplete recovery, the deltoid and rotator cuff muscles are most commonly affected.1
Incomplete paralysis can occur with sparing of either the anterior or the posterior portion of the deltoid
In such cases, atrophy may not be obvious and, if rotator cuff function
is preserved, shoulder range of mo-tion may be normal.1 However, when affected individuals exercise, they quickly fatigue, and their ab-duction strength is much less than normal Young athletic patients may
be able to compensate for complete deltoid paralysis and can often per-form activities of daily living with only limited disability However, in
Suprascapular nerve anastomosis
between suprascapular and
circumflex scapular arteries
Infraspinatus Fibrous capsule Humerus Axillary nerve
Deltoid
Branch to teres minor
Upper lateral cutaneous nerve of arm
Triangular interval Quadrilateral space
Triangular space
Figure 1 Posterior view of quadrilateral space (Adapted with permission from Anderson
JE [ed]: Grant’s Atlas of Anatomy, 7th ed Baltimore: Williams & Wilkins, 1978, p 6-39.)
Trang 3a work environment, they will easily
fatigue with overhead activities or
heavy lifting
The origin of deltoid paralysis
sometimes appears to be
atraumat-ic This condition has been referred
to as acute brachial neuritis or
Parsonage-Turner syndrome
Pa-tients typically relate a history of
severe shoulder pain that may
radi-ate down the arm and may last
from a few days to several weeks
The pain is soon followed by loss
of motor function in the affected
muscles Several nerves may be
in-volved (typically, the axillary, long
thoracic, and suprascapular nerves),
but occasionally only one nerve is
in-volved When brachial neuritis or
a mixed lesion is suspected, EMG
evaluation can be helpful in
delin-eating the problem Treatment
with oral corticosteroids has been
used empirically, although it has
not yet been established that these
drugs provide any clear benefit
The prognosis in atraumatic cases
is quite good, with most patients
achieving normal function.11
The quadrilateral space
syn-drome is another potential cause of
axillary neuropathy Symptoms
typically include a chronic, dull,
aching pain in the dominant
extremity, which can awaken the
patient at night Patients
infre-quently report a history of trauma
The findings on physical exami-nation are usually limited to tender-ness posteriorly along the shoulder joint Deltoid atrophy and lateral sensory changes are uncommon, and the EMG findings are usually normal If quadrilateral space syn-drome is suspected, a subclavicular arteriogram may be appropriate
This study is considered positive if posterior humeral circumflex artery occlusion occurs with less than 60 degrees of abduction On magnetic resonance (MR) imaging, signal changes in the deltoid and teres minor muscles have been noted to represent denervation patterns con-sistent with quadrilateral space syn-drome.12
Because this syndrome is diffi-cult to diagnose accurately, obser-vation is the usual treatment, as the vast majority of patients will im-prove over time Some patients benefit from surgical exploration of the quadrilateral space and decom-pression of the axillary nerve by re-lease of scar or tight fibrous bands.13
Evaluation
The clinical history is important in planning the treatment of patients who may have an axillary nerve injury Patients without a distinct episode of trauma may have a com-pressive neuropathy due to an en-larging mass or aneurysm Quad-rilateral space syndrome may also occur with minimal or no trauma If pain precedes the loss of motor func-tion, the diagnosis may be brachial neuritis A recent event of pene-trating trauma or surgical trauma makes axillary nerve injury likely
Clinicians should also carefully eval-uate the axillary nerve function of any patient with a shoulder disloca-tion or proximal humerus fracture prior to reduction However, al-though it is theoretically possible to reduce a dislocation or fracture forcefully enough to cause axillary
nerve injury, this has not been re-ported in the literature
The initial physical evaluation should include standard testing for active and passive range of motion of the shoulder, as well as for strength
of abduction, external rotation, and internal rotation In chronic cases, muscle atrophy should be assessed, remembering that if the posterior del-toid and teres minor are spared, the lesion must be distal to the quadrilat-eral space
A complete neurologic examina-tion of the extremity should be per-formed, specifically checking the function of the spinal accessory, suprascapular, long thoracic, radial, and musculocutaneous nerves In-volvement of the superior lateral cutaneous nerve of the arm may lead to sensory loss over the lateral aspect of the shoulder However, it
is important to remember that even patients with a complete deltoid motor deficit can present with only mild loss of sensation over the
later-al aspect of the shoulder Therefore, the diagnosis of axillary neuropathy should not rest on the presence or absence of sensation over the area of the deltoid
Standard radiographic examina-tions of the shoulder and cervical spine are helpful in determining whether a fracture, dislocation, or other pathologic process is associated with the nerve injury An EMG/NCS evaluation is important in confirm-ing the diagnosis and establishconfirm-ing a reference point for subsequent as-sessment and potential recovery These studies may also reveal lesions
in other nerves or in the proximal brachial plexus, which may affect the overall treatment plan
In chronic cases with established muscle atrophy, an MR imaging study of the shoulder can demon-strate increased signal on spin-echo sequences due to muscle replace-ment by fat.14 This can be helpful when examining for a combined nerve injury; attempting to delineate
Table 1
Etiology of Axillary Nerve Lesions
Closed blunt trauma
Traction injury to the shoulder
Penetrating trauma (sharp or
blunt)
Nerve compression due to mass
effect (aneurysm, tumor)
Parsonage-Turner syndrome
(brachial neuritis)
Quadrilateral space syndrome
Trang 4the involvement of smaller
mus-cles, such as the teres minor; or
seeking to identify a mass lesion
that may be causing compressive
neuropathy Evaluation of the
bra-chial plexus is often difficult to
ac-curately interpret and has not been
found to be helpful
Nonoperative Treatment
Patients with an atraumatic history
of axillary neuropathy should be
observed over a period of at least 3
months from the onset of
symp-toms before operative treatment is
considered (Fig 2) At 2 to 4 weeks,
EMG/NCS should be performed to
establish baseline values Physical
therapy should be instituted during
this period, emphasizing passive
and active assisted range of motion
The key element of therapy sessions should be to preserve the maximum range of motion so as to prevent joint contracture while awaiting the return of muscle function Electrical stimulation of the deltoid has been used to preserve muscle viability, although it is unclear whether this approach has any effect on ultimate outcome
The results of nonoperative treat-ment for atraumatic lesions have been generally quite good Even in cases of closed trauma involving a fracture or dislocation, satisfactory recovery occurs in most patients In
a study of 73 patients with a proxi-mal humerus fracture or disloca-tion, 24 (33%) had EMG/NCS evi-dence of an axillary nerve injury;
there were 9 complete and 15 partial
lesions.9 All patients recovered within 1 to 2 years, including those with complete nerve lesions but no objective loss of function
Leffert15has suggested that axil-lary nerve injury after fracture or dis-location is a more common entity than is usually appreciated, but be-lieves that most patients progress to full recovery Perkins and Watson Jones16 reviewed a series of 15 pa-tients with axillary neuropathy after dislocation and reported that 13 recovered fully and only 2 had per-manent paralysis In one series of 108 elderly patients with anterior shoul-der dislocation, 10 (9.3%) were noted
to have an axillary nerve injury, but all went on to full recovery by 12 months.17 In another study,18a high rate of axillary neuropathy was noted in patients over age 40 with a
Improvement No improvement Improvement No improvement
Continue observation
Repeat EMG/
NCS at 3 mo
Penetrating trauma
Sharp (e.g., knife, surgical blade)
Blunt (e.g., gunshot)
EMG/NCS within 1 wk
Repeat EMG/NCS
at 3 mo
Isolated axillary nerve lesion
• EMG/NCS
• Treat any associated fracture or dislocation
• Observation
• EMG/NCS
• Observation
• Repeat EMG/NCS
at 3 mo
• Observation
• EMG/NCS at 4 wk
Salvage procedure:
• Trapezius transfer
• Pectoralis major transfer
• Functioning free muscle transfer
If severe changes
on NCS, early exploration
If no clinical or EMG/NCS improvement, consider surgery at 3-6 mo
If no clinical
or EMG/NCS
improvement,
consider surgery
at 6 mo
Figure 2 Algorithm for treatment of isolated axillary nerve lesions (EMG/NCS = electromyographic and nerve conduction study).
Trang 5shoulder dislocation Six weeks after
injury, EMG/NCS evaluation showed
denervation patterns ranging from
moderate to severe in 28 (51%) of 55
patients At the 3-year follow-up
examination, no patient had
persis-tent axillary neuropathy; however, 6
(21%) of the 28 had symptomatic
rotator cuff tears
Operative Treatment
Operative treatment of axillary
neuropathy can be considered if no
clinical or EMG/NCS evidence of
recovery is present by 3 months
after injury.19-21 This is a
reason-able time frame for patients who
have sustained closed trauma
However, if the cause of the
axil-lary nerve dysfunction is a stab
wound or surgical insult, operative
exploration should be performed
much sooner In such instances,
EMG/NCS may be diagnostic of
disruption of axillary nerve
con-duction at less than 1 week after
injury, before axonal degeneration
occurs along the distal aspect of the
nerve A denervation pattern on
EMG testing will typically not be
present until approximately 2 to 3
weeks after injury, when
fibrilla-tion potentials can be observed
When assessing a patient with a
stab wound to the shoulder and
limited deltoid function, the NCS
should be obtained initially at 4 to
7 days after injury; if the findings
are equivocal, the clinician should
wait an additional 2 weeks before a
repeat EMG evaluation If the
ini-tial EMG/NCS results demonstrate
loss of conduction and a
denerva-tion pattern, early operative
explo-ration may be considered
Occasionally, axillary
neuropa-thy may be noted after elective
surgery, presumably due to
sus-tained traction or laceration injury
to the nerve Even in this setting,
however, immediate surgical
explo-ration is not always warranted, as
the patient may have a neurapraxia
or axonotmesis that will fully re-cover with nonoperative treatment
An early EMG/NCS evaluation can help define the nature of the nerve injury in such situations
For patients with a gunshot in-jury to the shoulder and evidence of axillary neuropathy, observation for
4 to 6 weeks may be prudent The blast effect during missile penetra-tion may have caused neurapraxia
or axonotmesis, both of which have
a good potential for spontaneous recovery
Although the most favorable re-sults of surgical treatment have been documented to occur with treatment initiated less than 6 months after injury, functional improvement can occur if surgical intervention is undertaken before
12 months.2,3,19 Significant clinical improvement is unlikely if surgical treatment is initiated 12 months or more after injury.20
Surgical Options
The axillary nerve is ideal for critical evaluation of the results of surgical treatment of motor nerve injuries The proximal monofascic-ular structure of the nerve, its com-position of primarily motor fibers, and its relatively short length are attributes that make it highly appro-priate for study of the effects of sur-gical intervention
The standard modalities of neu-rolysis, neurorrhaphy, nerve graft-ing, and neurotization have all been used in the treatment of axillary nerve injuries.19,22 The choice of treatment is ultimately determined
at surgery after exploration of the nerve If the nerve has been
recent-ly lacerated, neurorrhaphy alone can be successful However, if the injury is several weeks or months old, retraction and scarring of the cut ends of the nerve have occurred
Due to the relative confinement of the nerve and its oblique course over the subscapularis muscle and
through the quadrilateral space, mobilization of the nerve is often not possible, and nerve grafting must be performed When the nerve
is found to be intact but encased in scar or trapped in the quadrilateral space by fibrous bands, neurolysis
or decompression can be success-ful.3,4,14 Neurotization has also been utilized to correct axillary nerve le-sions with use of the thoracodorsal, phrenic, spinal accessory, and inter-costal nerves.22,23
Results of Surgical Treatment
In one series of 37 patients with axillary nerve injuries, 33 were treated by sural nerve grafting; 1, by direct repair; and 3, by neurolysis.19
Of those with isolated axillary nerve lesions, 23 of 25 achieved M4 or M5 strength postoperatively (as graded
by manual muscle testing according
to the Nerve Injuries Committee of the British Medical Research Coun-cil24) The large number of patients who required grafting illustrates the difficulty of adequately mobilizing the nerve for a direct repair The small number of patients who un-derwent neurolysis demonstrates that simple nerve compression by scar or fibrous bands is not common
In a series of 66 patients with axil-lary neuropathy,2027 patients un-derwent surgical exploration and grafting within 6 months of injury
Of these 27 patients, 9 recovered M5 strength, and 9 recovered M4 strength Thirteen other patients un-derwent neurolysis, with 10 achiev-ing grade M4 or M5 strength The 6 patients who underwent surgery more than 1 year after injury did not fare as well; only 1 patient achieved
a muscle grade of M4
Petrucci et al3 presented the re-sults in 15 patients who underwent sural nerve grafting an average of 5.8 months after injury In most cases, two sural nerve grafts were placed (length, 3 to 8 cm) All but 1
of the patients achieved a muscle grade of M4 or M5
Trang 6Chuang et al22reported on
neu-rotization with the use of the phrenic
or spinal accessory nerve, which
requires intercalary sural nerve
grafting with either donor nerve
The results were similar with the
two nerves The 23 patients who
underwent spinal accessory
neuroti-zation with bridging sural nerve
grafts had an average of 45 degrees
of improvement in abduction
The results of quadrilateral space
decompression have not been
re-ported as frequently as the results
of surgical repair after a traumatic
injury.14,25 Cahill and Palmer13
re-ported on 18 patients who
under-went decompression of the
quadri-lateral space; 8 patients achieved
dramatic relief of symptoms, and 8
had some relief Francel et al25
re-ported the results in 5 patients with
quadrilateral space syndrome after
a traumatic injury All 5 had
reso-lution of sensory deficits and
sub-jective improvement of shoulder
pain with surgical decompression
The most commonly performed
surgical procedure for persistent
axillary neuropathy is sural nerve
grafting Satisfactory results can be
achieved in most cases There are
two reasons why grafting is
com-monly needed First, because
trac-tion is a common pattern of injury,
the nerve may have several
centime-ters of stretch injury, resulting in a
neuroma in continuity Resection of
the neuroma necessitates a grafting
procedure in most situations, as it is
difficult to mobilize the nerve to
gain more length Second, the most
common area for injury of the nerve
is either proximal to or just at the
quadrilateral space A direct repair
is technically difficult to perform in
this area, because when a standard
anterior approach is used, the area
to be reconstructed is at the bottom
of a deep surgical exposure It is
preferable and technically easier to
perform a distal anastomosis with
nerve grafts through a posterior
approach and then pass the grafts
through the quadrilateral space, achieving a proximal tension-free anastomosis from the anterior ap-proach
Surgical Technique
Under general anesthesia, the patient is placed in the lateral decu-bitus position to facilitate both ante-rior and posteante-rior exposure of the shoulder, as well as access for har-vesting the sural nerve A modified deltopectoral approach is made from the clavicle to the deltoid in-sertion with the skin incision placed slightly more medial than usual (5
mm to 1 cm) This is important be-cause most of the surgical exposure will be centered more medially, under the area of the pectoralis major and pectoralis minor, rather than over the humeral head If there
is a prior surgical incision in the area, it can often be extended to gain adequate exposure
After development of the delto-pectoral interval and exposure of the clavipectoral fascia, the muscles originating from the coracoid are sequentially released, beginning with the short head of the biceps and coracobrachialis and followed
by the pectoralis minor The mus-cles may be taken down either by osteotomizing the tip of the cora-coid or by using an electrocautery device to detach them, with suture reattachment at closure If the pec-toralis, the coracobrachialis, and the short head of the biceps are released within 1 cm of their osseous origin, there is no danger of damage to the musculocutaneous nerve
The pectoralis major can then be either partially or completely re-leased from the humerus for greater exposure A cuff of tissue should
be left on the humerus to allow later repair at the end of the proce-dure Sufficient dissection should
be done to allow visualization of the axillary, radial, and musculocu-taneous nerves Early in the proce-dure, before releasing the muscular
attachments at the coracoid, the axillary nerve can be identified by passing a finger over the subscapu-laris muscle and sweeping inferi-orly This maneuver will usually hook the axillary nerve and allow it
to be palpated with the posterior humeral circumflex as it travels into the quadrilateral space (Fig 3).26
Adequate visualization of the axillary nerve is usually possible only after the pectoralis minor has been detached and retracted medi-ally The axillary and musculocuta-neous nerves branch off the poste-rior and lateral cords, respectively,
at approximately the level of the coracoid and can be most easily identified by following the nerves from distal to proximal The mus-culocutaneous nerve is identified as
it enters the coracobrachialis and then can be traced proximally to the lateral cord The axillary nerve can
be followed proximally from the quadrilateral space to the posterior cord As the dissection proceeds prox-imally, the much larger radial nerve can be identified and protected If nerve identification is not certain, a nerve stimulator should be used to establish which muscle groups are being innervated
Once the axillary, radial, and musculocutaneous nerves have been identified, the axillary nerve must be fully exposed by carefully dissecting
it from the adjoining brachial plexus The axillary artery and vein must be identified and protected, as they are also at risk during axillary nerve exposure After the axillary nerve has been well exposed proximally, surgical dissection proceeds distally until the area of the lesion is identi-fied Often this is located at or just proximal to the quadrilateral space
If the lesion grossly appears to be a neuroma, antegrade stimulation of the nerve can be performed with a nerve stimulator If muscle activity
is detected, neurolysis of the lesion should be done If no muscle activity
is noted, intraoperative EMG/NCS
Trang 7monitoring may be performed If no
electrical activity is recorded over
the deltoid, the neuroma should be
excised and grafted If either form
of stimulation demonstrates nerve
conduction, neurolysis may be
war-ranted, with use of an operating
microscope for magnification
If the lesion is located deep in the
quadrilateral space, a posterior
inci-sion will be needed to fully expose
the nerve This is possible with the
patient in the lateral decubitus
posi-tion A posterior incision is made
extending superiorly from the
pos-terior axillary crease to the
acrom-ion The inferior border of the
del-toid is mobilized superiorly, and the
nerve is identified as it exits the
quadrilateral space Detachment of
the deltoid is not necessary If distal
grafting is required at this point, the
motor fascicles to the deltoid are
identified and separated from the superior lateral cutaneous branch and the branch to the teres minor
The lateral position facilitates sural nerve harvest Usually, two or three sural nerve grafts measuring 4
to 8 cm are sutured to the distal stump of the nerve, first through the posterior exposure and then passed anterior for anastomosis to the proximal stump If a lesion is encountered very proximal in the axillary nerve, the proximal stump can be carefully dissected under the microscope 1 to 2 cm into the poste-rior cord without affecting fascicles directed to the radial nerve Nerve grafts should be sutured in a man-ner to allow a tension-free repair and should be checked with the arm in abduction and external rota-tion before completing the proximal anastomosis After closure, the arm
is placed in a sling Gentle passive and active exercises of the shoulder are begun at postoperative day 7, which helps promote axillary nerve gliding and prevents scarring
Late Presentation
Patients seen more than 24 months after injury present a treatment dilemma Due to intrinsic muscle wasting, nerve repair procedures are unproductive Patients should be carefully evaluated for physical limi-tations of the shoulder Young pa-tients often demonstrate full motion
of the shoulder and no limitations in activities of daily living However, there may be work restrictions due
to early fatigue with overhead activ-ities Most of these patients cannot
be helped predictably by further surgery, and workplace modifica-tions are recommended
In patients with poor shoulder abduction that limits activities of daily living but a normal rotator cuff, muscle transfer procedures can
be considered If sparing of the middle and posterior portions of the deltoid occurs, the innervated por-tion of the deltoid can be transposed anteriorly on the acromion Alter-natively, the pectoralis major can be transposed laterally on the acromion Mobilization of the pectoralis major can be limited by tethering of the pectoral nerves If the entire deltoid
is denervated, the trapezius can be detached from the acromion with a portion of bone and inserted into the proximal humerus This procedure may improve motion but rarely restores functional abduction Other techniques include bipolar latissimus dorsi transposition and free muscle transport
Summary
Axillary neuropathy is a potential complication of shoulder girdle
Deltoid
Subscapularis
Pectoralis minor
Axillary nerve
Radial nerve
Coracobrachialis/
short head of biceps
Figure 3 Technique of palpating the axillary nerve.
Trang 8injury, which can result in
signifi-cant disability Acute abduction
and traction are common injury
patterns that can produce a stretch
lesion in the nerve often just
proxi-mal to the quadrilateral space
Many injuries are mild and may
remain subclinical during
treat-ment and rehabilitation of the
pri-mary shoulder injury Most
axil-lary nerve lesions occur in closed
injuries and are either neurapraxia
or axonotmesis, for both of which
there is a good overall prognosis
for recovery
In addition to the initial clinical
examination, patients should be
evaluated with an EMG or nerve conduction study 2 to 4 weeks after injury and again at 12 weeks If no improvement is noted on these stud-ies or on clinical examination, surgi-cal treatment may be considered
Studies have shown that the best results of surgery occur when explo-ration is performed 3 to 6 months after injury In cases of sharp pene-trating trauma or neuropathy after a surgical procedure, exploration of the axillary nerve should be per-formed as soon as the diagnosis is made by physical examination and confirmed by nerve conduction study
Most patients with an axillary nerve injury have an excellent re-sponse to nonoperative treatment Favorable results can be expected for the rest if surgical repair is under-taken within 6 months of injury Surgical options include neurolysis, nerve grafting, and neurotization In most series, the majority of patients who required surgery underwent a nerve grafting procedure The results of nerve grafting have been encouraging, due to the relatively short distance from the lesion to the motor end-plate and the monofascic-ular nature of the proximal portion
of the axillary nerve
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