Journal of the American Academy of Orthopaedic Surgeons 328 Axillary 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 Axillary Nerve Injury: Diagnosis and Treatment Scott P. Steinmann, MD, and Elizabeth A. Moran, MD Scott P. Steinmann, MD, and Elizabeth A. Moran, MD Vol 9, No 5, September/October 2001 329 posterior 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.) Axillary Nerve Injury Journal of the American Academy of Orthopaedic Surgeons 330 a 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 establishing 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 Scott P. Steinmann, MD, and Elizabeth A. Moran, MD Vol 9, No 5, September/October 2001 331 the 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. Leffert 15 has 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 Jones 16 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, 18 a high rate of axillary neuropathy was noted in patients over age 40 with a Atraumatic Closed trauma Improvement No improvement Improvement No improvement Acute Chronic (>18 mo) 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). Axillary Nerve Injury Journal of the American Academy of Orthopaedic Surgeons 332 shoulder 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- cil 24 ). 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, 20 27 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 al 3 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. Scott P. Steinmann, MD, and Elizabeth A. Moran, MD Vol 9, No 5, September/October 2001 333 Chuang et al 22 reported 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 Palmer 13 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 al 25 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 posterior 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 Axillary Nerve Injury Journal of the American Academy of Orthopaedic Surgeons 334 monitoring 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. Scott P. Steinmann, MD, and Elizabeth A. Moran, MD Vol 9, No 5, September/October 2001 335 injury, 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. References 1. Friedman AH, Nunley JA II, Urbaniak JR, Goldner RD: Repair of isolated axillary nerve lesions after infraclavic- ular brachial plexus injuries: Case reports. Neurosurgery 1990;27:403-407. 2. Mikami Y, Nagano A, Ochiai N, Ya- mamoto S: Results of nerve grafting for injuries of the axillary and supra- scapular nerves. J Bone Joint Surg Br 1997;79:527-531. 3. Petrucci FS, Morelli A, Raimondi PL: Axillary nerve injuries: 21 cases treated by nerve graft and neurolysis. J Hand Surg [Am] 1982;7:271-278. 4. Richards RR, Hudson AR, Bertoia JT, Urbaniak JR, Waddell JP: Injury to the brachial plexus during Putti-Platt and Bristow procedures: A report of eight cases. Am J Sports Med 1987;15:374-380. 5. Burkhead WZ Jr, Scheinberg RR, Box G: Surgical anatomy of the axillary nerve. J Shoulder Elbow Surg 1992;1:31-36. 6. Aszmann OC, Dellon AL: The internal topography of the axillary nerve: An anatomic and histologic study as it relates to microsurgery. J Reconstr Microsurg 1996;12:359-363. 7. Sunderland S: Nerves and Nerve Injuries, 2nd ed. Edinburgh: Churchill Living- stone, 1978, pp 843-848. 8. Leffert RD, Seddon H: Infraclavicular brachial plexus injuries. J Bone Joint Surg Br 1965;47:9-22. 9. Blom S, Dahlbäck LO: Nerve injuries in dislocations of the shoulder joint and fractures of the neck of the hu- merus: A clinical and electromyo- graphical study. Acta Chir Scand 1970; 136:461-466. 10. Perlmutter GS, Leffert RD, Zarins B: Direct injury to the axillary nerve in athletes playing contact sports. Am J Sports Med 1997;25:65-68. 11. Dillin L, Hoaglund FT, Scheck M: Brachial neuritis. J Bone Joint Surg Am 1985;67:878-880. 12. Linker CS, Helms CA, Fritz RC: Quadri- lateral space syndrome: Findings at MR imaging. Radiology 1993;188:675-676. 13. Cahill BR, Palmer RE: Quadrilateral space syndrome. J Hand Surg [Am] 1983; 8:65-69. 14. Tuckman GA, Devlin TC: Axillary nerve injury after anterior gleno- humeral dislocation: MR findings in three patients. AJR Am J Roentgenol 1996;167:695-697. 15. Leffert RD: Neurological problems, in Rockwood CA Jr, Matsen FA III (eds): The Shoulder. Philadelphia: WB Saun- ders, 1990, vol 2, pp 765-767. 16. Perkins G, Watson Jones R: Fractures in the region of the shoulder-joint. Proc R Soc Med 1936;29:1055-1072. 17. Gumina S, Postacchini F: Anterior dislocation of the shoulder in elderly patients. J Bone Joint Surg Br 1997;79: 540-543. 18. Toolanen G, Hildingsson C, Hedlund T, Knibestöl M, Öberg L: Early complica- tions after anterior dislocation of the shoulder in patients over 40 years: An ul- trasonographic and electromyographic study. Acta Orthop Scand 1993;64:549-552. 19. Alnot JY, Valenti P: Surgical repair of the axillary nerve: Apropos of 37 cases [French]. Int Orthop 1991;15:7-11. 20. Coene LNJEM, Narakas AO: Opera- tive management of lesions of the axil- lary nerve, isolated or combined with other nerve lesions. Clin Neurol Neuro- surg 1992;94(suppl):S64-S66. 21. Nunley JA, Gabel G: Axillary nerve, in Gelberman RH (ed): Operative Nerve Repair and Reconstruction. Phila- delphia: JB Lippincott, 1991, vol 1, pp 437-445. 22. Chuang DCC, Lee GW, Hashem F, Wei FC: Restoration of shoulder abduction by nerve transfer in avulsed brachial plexus injury: Evaluation of 99 patients with various nerve transfers. Plast Reconstr Surg 1995;96:122-128. 23. Dai SY, Lin DX, Han Z, Zhoug SZ: Trans- ference of thoracodorsal nerve to mus- culocutaneous or axillary nerve in old traumatic injury. J Hand Surg [Am] 1990; 15:36-37. 24. Seddon HJ (ed): Peripheral Nerve Inju- ries. Medical Research Council Special Report Series No. 282. London: Her Majesty’s Stationery Office, 1954. 25. Francel TJ, Dellon AL, Campbell JN: Quadrilateral space syndrome: Diag- nosis and operative decompression technique. Plast Reconstr Surg 1991;87: 911-916. 26. Flatow EL, Bigliani LU: Locating and protecting the axillary nerve in shoul- der surgery: The tug test. Orthop Rev 1992;21:503-505. . 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. 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 confirm- ing the diagnosis and establishing a reference point for subsequent as- sessment and potential recovery. These studies may also reveal lesions in other nerves or in the proximal brachial