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Supracapular nerve entrapment
Surg Neurol 1983;20:493-7
493
Supracapular Nerve Entrapment J a m e s B. S a r n o , M . D .
Sarno JB. Suprascapular nerve entrapment. Surg Neurol 1983;20:493-7.
Suprascapular nerve c o m p r e s s i o n is a true peripheral ent r a p m e n t n e u r o p a t h y that can be cured by lysis of the suprascapular ligament and freeing the suprascapular nerve. It is a rare entity that must be considered in the differential diagnosis of radicular pain, as well as that of the shoulder. Four examples of suprascapular nerve neuropathy in three patients are described, including one case of bilateral entrapment; all were young females. One was diagnosed as systemic lupus erythematosus (case 3); it is n o w considered that a second patient (case 2) may have the same disorder. The clinical, anatomic, and surgical considerations of the suprascapular nerve are considered in this paper. KEY WORDS: Suprascapular nerve; Entrapment neuropathy; Radicular pain; Shoulder pain; Systemic lupus erythematosus; Electromyogram
iculopathy of the fifth cervical nerve, including not only pain in the shoulder but also pain in the neck and accompanied by headache and radiation of the pain down along the arm.
Anatomy
The suprascapular nerve is a mixed peripheral nerve, not a pure motor nerve. It arises from the upper trunk of the brachial plexus, supplies m o t o r innervation to the supraspinatus and infraspinatus muscles. T h e sensory c o m p o n e n t has no supply to the skin of the area, but does supply articular branches to the shoulder and acromioclavicular joints. Rengachary et al [6] presented an excellent review and diagrams of the suprascapular nerve and its distributions (Figure 1).
Case Histories
Suprascapular nerve e n t r a p m e n t neuropathy is a rather u n c o m m o n entity, which has recently been described in the literature. A series of five cases was reported in 1975 by Clein [2]. In 1976, Murray [4] refers to additional cases. The clinical manifestations are deep aching pain in the shoulder, weakness o f abduction and external rotation of the shoulder. Bateman [1] states that pain is not a feature of these lesions because the nerve is entirely a m o t o r nerve. Kopell and T h o m p s o n [3] state that not only weakness, but also pain, including pain along the radial aspect o f the arm and forearm, is indeed one of the symptoms. In their monograph, however, they reported no cases. T h e article by Clein [2] has one patient (case 1) who had radiation of pain down the midarm to the elbow, as well as pain over the scapular muscles. The purpose of this paper is to report four cases of suprascapular nerve entrapment. In three female patients, the e n t r a p m e n t neuropathy was similar to a rad-
Address reprint requests to:James B. Sarno, M.D., 1035 Park Boulevard, Massapequa Park, New York 11752. © 1983 by Elsevier Science Publishing,Co., Inc.
Case 1 A 35-year-old, right-handed woman had experienced pain in the left shoulder radiating down the left arm to the mid portion of the extremity and stiffness of the neck since she was involved in an automobile accident on June 17, 1974, when her extended arms were jammed against the steering wheel after her car was struck from the rear. She noted weakness of the left shoulder as well. The patient was treated conservatively for a cervical radiculopathy. When this failed, the patient underwent a myelogram, which was normal. She then came under my care and was found to have local tenderness, muscle spasm, and atrophy of the hypothenar muscles of the left hand. Electromyogram on February 12, 1975, was negative except for fibrillations in the infraspinatus muscle (Table 1}. A diagnostic block of the left suprascapular nerve erased the symptoms o f pain and stiffness of the neck. On April 4, 1975, the patient had a lysis of the left suprascapular nerve and has been totally asymptomatic since then. Immediately postoperatively all pain, stiffness, and radiating pain ceased. She remains well and asymptomatic, but has refused a second electromyelogram. There is no atrophy of muscle, and she leads a normal life. 0090-3019/8~/S2,.00
494
Surg Neurol 1983;20:493-7
SUPRASCAPULAR ARTERY
SUPRASCAPULAR NERVE
Sarno
~
TRANSVERSE
SCAPULAR LIGAMENT >j \c:i
SUPRASPN I AOF TUS~sPN I EI~M '~' ' ' ' ,T~~"~~ 'A~I : i"--:~-~' l L' ' ; ' ~ '] SCAPULA ~
' /
~
SUPRASCAPULARNERVE
•CAPSULAR BRANCHES
Figure 1. Anatomy of right suprascapular nerve. (Rengachary et al. Suprascapular entrapment neuropathy. Neurology 1979:5.'441-55. With permission of the author.)
OFTHENERVE
INFRASPINATUSM
T a b l e 1. Electromyographic and Postoperative Results Patient and operation
1
Patient 2/12/75 (left side only)
2
Patient 8/6/75 (left side only)
12/13/82
Patient
3
Neurological findings before operation
Comments
Fibrillation potentials in left infraspinatus muscles
Patient has experienced no recurrence o f pain since treatment
Fibrillation potentials in left supraspinatus and left infraspinatus muscles Nerve conduction velocity: right suprascapular nerve, 10 m/s; left suprascapular nerve, 3.6 m/s Brief, small amplitude, polyphasic motor units in proximal muscles o f both upper extremities
Patient returned to work as a recovery room nurse Patient now considered to have collagen disease (possible systemic lupus erythematosus)
Electromyogram diagnostic of myopathy
First operation 12/24/80 (left side only)
Supraspinatus and infraspinatus muscles showed hyperirritability and increased insertional activity; latency: 4.5 ms (delayed) on left side
Patient now diagnosed as having systemic lupus erythematosus; suprascapular nerve symptoms are gone, but generalized muscle ache and migratory large-joint arthritis are present.
Left side: latency 4.0 ms vs 4.5 on 12/13/79 Right side: increased insertional activity and hyperirritability o f supraspinatus and infraspinatus muscles; latency 6.6 ms vs 3.0 ms on 12/13/79 (normal)
Right side: symptoms preferable to suprascapular nerve are abated; note change from normal on right side to abnormal, and slight return toward normal on left side.
Few volitional motor units, right supraspinatus; right infraspinatus is normal Some positive waves and fibrillations in left supraspinatus muscle; left infraspinatus is normal Right median nerve at wrist is closed, as in right ulnar nerve at elbow
Improving lesions of suprascapular nerves
Second operatton 12/24/80 (both sides)
Third operation 8/30/82 (right side only)
Abbreviations: m = meter; s = second; ms = millisecond.
Early lesions of right median and ulnar nerves
Suprascapular Nerve Entrapment
Case 2 A 34-year-old, right-handed woman was seen on June 16, 1975, with a 1-month history of pain in the left shoulder and neck radiating down the left upper extremity and accompanied by headache. The patient had no definite history of an injury. She was a nurse in an intensive care unit where she was pushing and pulling many patients, particularly patients who were partially paralyzed. Neurologically there was a weakness of abduction of the shoulder. A diagnosis of a left C-6 radiculitis was made. The patient was treated conservatively. When she failed to respond, she had an electromyogram which showed delayed nerve conduction and fibrillations in the left supraspinatus and infraspinatus muscles (Table 1). The patient had a diagnostic block of the left suprascapular nerve with 1% local lidocaine with immediate total relief of all symptoms. In August, 1975, she had surgical lysis of the suprascapular nerve with total relief of symptoms. She now works a full shift as a recovery room nurse. This patient has a tentative diagnosis of systemic lupus erythematosus. She has intermittent recurring malar rash, elevated erythrocyte sedementation rate and a positive antinuclear antibody test, as well as muscular aches since the summer of 1982. Repeat electromyogram (December 1982) shows a diffuse myopathy with proximal musculature involved more than peripheral musculature in both upper and lower extremities. The symptoms of suprascapular nerve entrapment have not recurred.
Case 3 An 18-year-old, right-handed woman was first seen on October 15, 1979, because of severe headaches on the left side of the head and pain radiating down the left upper extremity along the radial aspect of the arm and forearm. She had experienced headaches prior to this. The headaches became severe when she fell on her left shoulder during a judo class in N o v e m b e r of 1978. Patient had a second fall on her left shoulder in March 1979. N o radiographs of shoulder or neck were made. Neurologically test results were normal. However, there was spasm of the cervical musculature and tenderness of the muscles of the left neck, as well as of the left shoulder. Examination was negative except for an electromyogram on D e c e m b e r 13, 1979, which showed evidence of delayed nerve conduction and hyperirritability of the supra- and infraspinatus muscles. The patient refused therapy except for Sulindac (200 mg b.i.d.), to which she failed to respond. Because she
Surg Neurol 1983;20:493-7
495
was involved in physical activity at college, she continued this in hopes of decreasing her pain. By August 1980 the patient had endured such severe pain that she elected to have operative lysis of the suprascapular nerve. On August 19, 1980, she underwent lysis of the left suprascapular nerve with immediate cessation of all symptoms. While she was recuperating from this procedure, she was riding her bicycle, from which she fell. She fell directly upon the right shoulder, which immediately began her pain again. She continued her own physical therapy, but after 4 months the pain became so severe that she again presented herself for examination. She noted, at this time, pain in the shoulder radiating up the neck with stiffness of the neck and pain radiating along the radial side of the forearm. There was marked tenderness along the suprascapular notch. The patient underwent a repeat electromyogram, which showed compression of the right suprascapular nerve with improvement o f the left upon which she had previously been operated (Table 1). On January 2, 1981, the patient underwent suprascapular nerve lysis at the right suprascapular notch with complete cessation of symptoms. However, the patient developed a hematoma after the operation, which was treated conservatively. The patient noted a general "weakness" of both shoulders, as well as pain and headache. Patient is now diagnosed as having systemic lupus erythematosus. She returned for a follow-up examination on August 23, 1982, and complained of headaches and migratory polyarthritis. The nonspecific "weakness" of the shoulder was not present. On examination, the right supraspinatus muscle was markedly atrophied. Yet clinically, there was no weakness on either side. Electromyogram showed bilateral evidence of denervation of the supraspinatus muscles, right more than left, related to the old trauma. Additionally, there was evidence of early lesions of the right ulnar nerve at the elbow and right median nerve at the wrist.
Surgical Technique The patient was placed prone on bolsters with the head elevated roughly 30 degrees. The head is turned opposite to the side that is to be operated upon, and the hand on the side of the compression is held downward mechanically (Figure 2). An incision was made over the lateral 7 . 5 - 1 0 cm of the scapular spine. The incision was extended downward to the scapular spine itself and the supraspinatus and trapezius muscles were elevated subperiosteally from the spine.
496
Surg Neurol 1983;20:493-7
Sarno
Figure 2. Positioning of patient for right suprascapular nem,e decompression. (Regnachary et al. Suprascapular entrapment neuropathy. Neurology 1979:5.'441-55. With permission of the author.)
l The trapezius was then freed from the supraspinatus so that dissection both above and below the supraspinatus could be carried out. The suprascapular artery and vein were found--immediately above the transverse scapular ligament below which the suprascapular nerve was entrapped. The nerve was identified and then the ligament was incised by using a metal instrument beneath the ligament, but above the nerve. The nerve itself was visualized over 5 - 6 cm so that it was totally free (Figure 3). Rask [5] treated two suprascapular nerve compressions with suprascapular notch resection after there had been previous lysis of the suprascapular ligament only. Because o f my own experience and the experience described in the literature, which shows that patients have excellent relief with lysis o f the ligament only, it is difficult to understand the cause o f recurrence and need for resection of the suprascapular notch. Although most authors reviewed preferred the posterior approach, Batemen [ 1] performed a procedure in which the patient was in the semiseated position. An incision was made from the midposterior cervical triangle laterally and obliquely over the edge of the tra-
pezius. H e identified roots C-5 and C-6 and the suprascapular nerve was exposed as it arises from the upper root. H e then followed it to the notch and lysed the suprascapular ligament. However, Dr. Batemen described "neuromas" in all cases. In my cases, as well as those found in the literature, I have found no evidence of neuromas.
Discussion Compression of the suprascapular nerve is a relatively rare entity. The causes of the compression, as gleaned from the literature, indicate direct trauma such as falling on the shoulder, trauma due to objects falling upon the shoulder, and fractures of the scapula are all part of the cause of this entrapment. Compression o f the nerve at the suprascapular notch leads to the cardinal symptom of deep aching of the shoulder. Signs of compression of the suprascapular nerve are atrophy of the supraspinatus and infraspinatus muscles, as well as weakness of abduction and external rotation of the arm. Additionally, a cross adduction test [3] is very helpful in making this clinical diagnosis. In this test
!RY OMOHY(
ISION
I
TRAPEZIUS SUPRASP. . . . . . . . . . .
Figure 3. Left: Incision for right suprascapular nerve decompression. Right." Surgical anatomy of right suprascapular nerve decompression. (Rengachary et aL Suprascapular entrapment neuropathy. Neurology 1979,'5.'441-55. With permission of the author.)
Suprascapular Nerve Entrapment
the patient, with his arm fully extended, crossadducts the arm across the chest. If there is compression of the suprascapular nerve, adduction is markedly limited and leads to pain and discontinuation o f the activity. An additional test is injection of the nerve with lidocaine with relief of symptoms. The single most important diagnostic test is electromyography, demonstrating delayed conduction of the suprascapular nerve or of fibrillations o f the supraspinatus or infraspinatus muscles, or both. This series o f three cases of suprascapular nerve compression in three young women, two of whom (cases 1 and 3) suffered direct trauma to the area either by falling on the shoulder or having the shoulder forceably pushed backward in an automobile accident with the extended arms being jammed against the steering wheel shows that radiating pain is also part of the syndrome in certain cases. Case 2 involves a nurse who developed symptoms at a time when she was working with many partially paralyzed patients in an intensive care unit. N o definite history o f trauma was elicted. She too had a cervical radicularlike syndrome from compression of the suprascapular nerve. It must be added, at this point, that patient 3, after obtaining relief of pain from her procedure has been diagnosed as having systemic lupus erythematosus.
Surg Neurol 1983;20:493-7
497
Patient 2 is now also considered to have possible systemic lupus. H e r erythrocyte sedimentation rate and fluorescent antinuclear antibodies are positive. She has an intermittent recurring malar rash. It is difficult to know what the presence of systemic lupus erythematosus in patients 2 and 3 means. This is c o m m o n among women and patient 2 has two female relatives with true arthritis, which is a common sign of systemic lupus erythematosus. Whether this is causative or a happenstance cannot be stated, but one must wonder when two o f three patients with a rare entity develop the same disease. References 1. Bateman JE. Nerve lesions about the shoulder. Orthoped Clin North Am 1980;11:319-21. 2. Clein LJ. Suprascapular entrapment neuropathy. J Neurosurg 1975;43:337-42. 3. Kopell HP, Thompson WAL. Peripheral entrapment neuropathies. Baltimore: Williams & Wilkins, 1963. 4. Murray JW. Suprascapular entrapment neuropathy [lett]. J Neurosurg 1976;44:649-50. 5. Rask MR. Suprascapular nerve entrapment. Report of two cases treated with suprascapular notch resection. Clin Orthoped 1977;123:73-5. 6. Rengachary SS, NeffJP, Singer PA, Brackett CE. Suprascapular entrapment neuropathy. A clinical, anatomical comparative study. Neurosurgery 1979;5:441-52.
493
Supracapular Nerve Entrapment J a m e s B. S a r n o , M . D .
Sarno JB. Suprascapular nerve entrapment. Surg Neurol 1983;20:493-7.
Suprascapular nerve c o m p r e s s i o n is a true peripheral ent r a p m e n t n e u r o p a t h y that can be cured by lysis of the suprascapular ligament and freeing the suprascapular nerve. It is a rare entity that must be considered in the differential diagnosis of radicular pain, as well as that of the shoulder. Four examples of suprascapular nerve neuropathy in three patients are described, including one case of bilateral entrapment; all were young females. One was diagnosed as systemic lupus erythematosus (case 3); it is n o w considered that a second patient (case 2) may have the same disorder. The clinical, anatomic, and surgical considerations of the suprascapular nerve are considered in this paper. KEY WORDS: Suprascapular nerve; Entrapment neuropathy; Radicular pain; Shoulder pain; Systemic lupus erythematosus; Electromyogram
iculopathy of the fifth cervical nerve, including not only pain in the shoulder but also pain in the neck and accompanied by headache and radiation of the pain down along the arm.
Anatomy
The suprascapular nerve is a mixed peripheral nerve, not a pure motor nerve. It arises from the upper trunk of the brachial plexus, supplies m o t o r innervation to the supraspinatus and infraspinatus muscles. T h e sensory c o m p o n e n t has no supply to the skin of the area, but does supply articular branches to the shoulder and acromioclavicular joints. Rengachary et al [6] presented an excellent review and diagrams of the suprascapular nerve and its distributions (Figure 1).
Case Histories
Suprascapular nerve e n t r a p m e n t neuropathy is a rather u n c o m m o n entity, which has recently been described in the literature. A series of five cases was reported in 1975 by Clein [2]. In 1976, Murray [4] refers to additional cases. The clinical manifestations are deep aching pain in the shoulder, weakness o f abduction and external rotation of the shoulder. Bateman [1] states that pain is not a feature of these lesions because the nerve is entirely a m o t o r nerve. Kopell and T h o m p s o n [3] state that not only weakness, but also pain, including pain along the radial aspect o f the arm and forearm, is indeed one of the symptoms. In their monograph, however, they reported no cases. T h e article by Clein [2] has one patient (case 1) who had radiation of pain down the midarm to the elbow, as well as pain over the scapular muscles. The purpose of this paper is to report four cases of suprascapular nerve entrapment. In three female patients, the e n t r a p m e n t neuropathy was similar to a rad-
Address reprint requests to:James B. Sarno, M.D., 1035 Park Boulevard, Massapequa Park, New York 11752. © 1983 by Elsevier Science Publishing,Co., Inc.
Case 1 A 35-year-old, right-handed woman had experienced pain in the left shoulder radiating down the left arm to the mid portion of the extremity and stiffness of the neck since she was involved in an automobile accident on June 17, 1974, when her extended arms were jammed against the steering wheel after her car was struck from the rear. She noted weakness of the left shoulder as well. The patient was treated conservatively for a cervical radiculopathy. When this failed, the patient underwent a myelogram, which was normal. She then came under my care and was found to have local tenderness, muscle spasm, and atrophy of the hypothenar muscles of the left hand. Electromyogram on February 12, 1975, was negative except for fibrillations in the infraspinatus muscle (Table 1}. A diagnostic block of the left suprascapular nerve erased the symptoms o f pain and stiffness of the neck. On April 4, 1975, the patient had a lysis of the left suprascapular nerve and has been totally asymptomatic since then. Immediately postoperatively all pain, stiffness, and radiating pain ceased. She remains well and asymptomatic, but has refused a second electromyelogram. There is no atrophy of muscle, and she leads a normal life. 0090-3019/8~/S2,.00
494
Surg Neurol 1983;20:493-7
SUPRASCAPULAR ARTERY
SUPRASCAPULAR NERVE
Sarno
~
TRANSVERSE
SCAPULAR LIGAMENT >j \c:i
SUPRASPN I AOF TUS~sPN I EI~M '~' ' ' ' ,T~~"~~ 'A~I : i"--:~-~' l L' ' ; ' ~ '] SCAPULA ~
' /
~
SUPRASCAPULARNERVE
•CAPSULAR BRANCHES
Figure 1. Anatomy of right suprascapular nerve. (Rengachary et al. Suprascapular entrapment neuropathy. Neurology 1979:5.'441-55. With permission of the author.)
OFTHENERVE
INFRASPINATUSM
T a b l e 1. Electromyographic and Postoperative Results Patient and operation
1
Patient 2/12/75 (left side only)
2
Patient 8/6/75 (left side only)
12/13/82
Patient
3
Neurological findings before operation
Comments
Fibrillation potentials in left infraspinatus muscles
Patient has experienced no recurrence o f pain since treatment
Fibrillation potentials in left supraspinatus and left infraspinatus muscles Nerve conduction velocity: right suprascapular nerve, 10 m/s; left suprascapular nerve, 3.6 m/s Brief, small amplitude, polyphasic motor units in proximal muscles o f both upper extremities
Patient returned to work as a recovery room nurse Patient now considered to have collagen disease (possible systemic lupus erythematosus)
Electromyogram diagnostic of myopathy
First operation 12/24/80 (left side only)
Supraspinatus and infraspinatus muscles showed hyperirritability and increased insertional activity; latency: 4.5 ms (delayed) on left side
Patient now diagnosed as having systemic lupus erythematosus; suprascapular nerve symptoms are gone, but generalized muscle ache and migratory large-joint arthritis are present.
Left side: latency 4.0 ms vs 4.5 on 12/13/79 Right side: increased insertional activity and hyperirritability o f supraspinatus and infraspinatus muscles; latency 6.6 ms vs 3.0 ms on 12/13/79 (normal)
Right side: symptoms preferable to suprascapular nerve are abated; note change from normal on right side to abnormal, and slight return toward normal on left side.
Few volitional motor units, right supraspinatus; right infraspinatus is normal Some positive waves and fibrillations in left supraspinatus muscle; left infraspinatus is normal Right median nerve at wrist is closed, as in right ulnar nerve at elbow
Improving lesions of suprascapular nerves
Second operatton 12/24/80 (both sides)
Third operation 8/30/82 (right side only)
Abbreviations: m = meter; s = second; ms = millisecond.
Early lesions of right median and ulnar nerves
Suprascapular Nerve Entrapment
Case 2 A 34-year-old, right-handed woman was seen on June 16, 1975, with a 1-month history of pain in the left shoulder and neck radiating down the left upper extremity and accompanied by headache. The patient had no definite history of an injury. She was a nurse in an intensive care unit where she was pushing and pulling many patients, particularly patients who were partially paralyzed. Neurologically there was a weakness of abduction of the shoulder. A diagnosis of a left C-6 radiculitis was made. The patient was treated conservatively. When she failed to respond, she had an electromyogram which showed delayed nerve conduction and fibrillations in the left supraspinatus and infraspinatus muscles (Table 1). The patient had a diagnostic block of the left suprascapular nerve with 1% local lidocaine with immediate total relief of all symptoms. In August, 1975, she had surgical lysis of the suprascapular nerve with total relief of symptoms. She now works a full shift as a recovery room nurse. This patient has a tentative diagnosis of systemic lupus erythematosus. She has intermittent recurring malar rash, elevated erythrocyte sedementation rate and a positive antinuclear antibody test, as well as muscular aches since the summer of 1982. Repeat electromyogram (December 1982) shows a diffuse myopathy with proximal musculature involved more than peripheral musculature in both upper and lower extremities. The symptoms of suprascapular nerve entrapment have not recurred.
Case 3 An 18-year-old, right-handed woman was first seen on October 15, 1979, because of severe headaches on the left side of the head and pain radiating down the left upper extremity along the radial aspect of the arm and forearm. She had experienced headaches prior to this. The headaches became severe when she fell on her left shoulder during a judo class in N o v e m b e r of 1978. Patient had a second fall on her left shoulder in March 1979. N o radiographs of shoulder or neck were made. Neurologically test results were normal. However, there was spasm of the cervical musculature and tenderness of the muscles of the left neck, as well as of the left shoulder. Examination was negative except for an electromyogram on D e c e m b e r 13, 1979, which showed evidence of delayed nerve conduction and hyperirritability of the supra- and infraspinatus muscles. The patient refused therapy except for Sulindac (200 mg b.i.d.), to which she failed to respond. Because she
Surg Neurol 1983;20:493-7
495
was involved in physical activity at college, she continued this in hopes of decreasing her pain. By August 1980 the patient had endured such severe pain that she elected to have operative lysis of the suprascapular nerve. On August 19, 1980, she underwent lysis of the left suprascapular nerve with immediate cessation of all symptoms. While she was recuperating from this procedure, she was riding her bicycle, from which she fell. She fell directly upon the right shoulder, which immediately began her pain again. She continued her own physical therapy, but after 4 months the pain became so severe that she again presented herself for examination. She noted, at this time, pain in the shoulder radiating up the neck with stiffness of the neck and pain radiating along the radial side of the forearm. There was marked tenderness along the suprascapular notch. The patient underwent a repeat electromyogram, which showed compression of the right suprascapular nerve with improvement o f the left upon which she had previously been operated (Table 1). On January 2, 1981, the patient underwent suprascapular nerve lysis at the right suprascapular notch with complete cessation of symptoms. However, the patient developed a hematoma after the operation, which was treated conservatively. The patient noted a general "weakness" of both shoulders, as well as pain and headache. Patient is now diagnosed as having systemic lupus erythematosus. She returned for a follow-up examination on August 23, 1982, and complained of headaches and migratory polyarthritis. The nonspecific "weakness" of the shoulder was not present. On examination, the right supraspinatus muscle was markedly atrophied. Yet clinically, there was no weakness on either side. Electromyogram showed bilateral evidence of denervation of the supraspinatus muscles, right more than left, related to the old trauma. Additionally, there was evidence of early lesions of the right ulnar nerve at the elbow and right median nerve at the wrist.
Surgical Technique The patient was placed prone on bolsters with the head elevated roughly 30 degrees. The head is turned opposite to the side that is to be operated upon, and the hand on the side of the compression is held downward mechanically (Figure 2). An incision was made over the lateral 7 . 5 - 1 0 cm of the scapular spine. The incision was extended downward to the scapular spine itself and the supraspinatus and trapezius muscles were elevated subperiosteally from the spine.
496
Surg Neurol 1983;20:493-7
Sarno
Figure 2. Positioning of patient for right suprascapular nem,e decompression. (Regnachary et al. Suprascapular entrapment neuropathy. Neurology 1979:5.'441-55. With permission of the author.)
l The trapezius was then freed from the supraspinatus so that dissection both above and below the supraspinatus could be carried out. The suprascapular artery and vein were found--immediately above the transverse scapular ligament below which the suprascapular nerve was entrapped. The nerve was identified and then the ligament was incised by using a metal instrument beneath the ligament, but above the nerve. The nerve itself was visualized over 5 - 6 cm so that it was totally free (Figure 3). Rask [5] treated two suprascapular nerve compressions with suprascapular notch resection after there had been previous lysis of the suprascapular ligament only. Because o f my own experience and the experience described in the literature, which shows that patients have excellent relief with lysis o f the ligament only, it is difficult to understand the cause o f recurrence and need for resection of the suprascapular notch. Although most authors reviewed preferred the posterior approach, Batemen [ 1] performed a procedure in which the patient was in the semiseated position. An incision was made from the midposterior cervical triangle laterally and obliquely over the edge of the tra-
pezius. H e identified roots C-5 and C-6 and the suprascapular nerve was exposed as it arises from the upper root. H e then followed it to the notch and lysed the suprascapular ligament. However, Dr. Batemen described "neuromas" in all cases. In my cases, as well as those found in the literature, I have found no evidence of neuromas.
Discussion Compression of the suprascapular nerve is a relatively rare entity. The causes of the compression, as gleaned from the literature, indicate direct trauma such as falling on the shoulder, trauma due to objects falling upon the shoulder, and fractures of the scapula are all part of the cause of this entrapment. Compression o f the nerve at the suprascapular notch leads to the cardinal symptom of deep aching of the shoulder. Signs of compression of the suprascapular nerve are atrophy of the supraspinatus and infraspinatus muscles, as well as weakness of abduction and external rotation of the arm. Additionally, a cross adduction test [3] is very helpful in making this clinical diagnosis. In this test
!RY OMOHY(
ISION
I
TRAPEZIUS SUPRASP. . . . . . . . . . .
Figure 3. Left: Incision for right suprascapular nerve decompression. Right." Surgical anatomy of right suprascapular nerve decompression. (Rengachary et aL Suprascapular entrapment neuropathy. Neurology 1979,'5.'441-55. With permission of the author.)
Suprascapular Nerve Entrapment
the patient, with his arm fully extended, crossadducts the arm across the chest. If there is compression of the suprascapular nerve, adduction is markedly limited and leads to pain and discontinuation o f the activity. An additional test is injection of the nerve with lidocaine with relief of symptoms. The single most important diagnostic test is electromyography, demonstrating delayed conduction of the suprascapular nerve or of fibrillations o f the supraspinatus or infraspinatus muscles, or both. This series o f three cases of suprascapular nerve compression in three young women, two of whom (cases 1 and 3) suffered direct trauma to the area either by falling on the shoulder or having the shoulder forceably pushed backward in an automobile accident with the extended arms being jammed against the steering wheel shows that radiating pain is also part of the syndrome in certain cases. Case 2 involves a nurse who developed symptoms at a time when she was working with many partially paralyzed patients in an intensive care unit. N o definite history o f trauma was elicted. She too had a cervical radicularlike syndrome from compression of the suprascapular nerve. It must be added, at this point, that patient 3, after obtaining relief of pain from her procedure has been diagnosed as having systemic lupus erythematosus.
Surg Neurol 1983;20:493-7
497
Patient 2 is now also considered to have possible systemic lupus. H e r erythrocyte sedimentation rate and fluorescent antinuclear antibodies are positive. She has an intermittent recurring malar rash. It is difficult to know what the presence of systemic lupus erythematosus in patients 2 and 3 means. This is c o m m o n among women and patient 2 has two female relatives with true arthritis, which is a common sign of systemic lupus erythematosus. Whether this is causative or a happenstance cannot be stated, but one must wonder when two o f three patients with a rare entity develop the same disease. References 1. Bateman JE. Nerve lesions about the shoulder. Orthoped Clin North Am 1980;11:319-21. 2. Clein LJ. Suprascapular entrapment neuropathy. J Neurosurg 1975;43:337-42. 3. Kopell HP, Thompson WAL. Peripheral entrapment neuropathies. Baltimore: Williams & Wilkins, 1963. 4. Murray JW. Suprascapular entrapment neuropathy [lett]. J Neurosurg 1976;44:649-50. 5. Rask MR. Suprascapular nerve entrapment. Report of two cases treated with suprascapular notch resection. Clin Orthoped 1977;123:73-5. 6. Rengachary SS, NeffJP, Singer PA, Brackett CE. Suprascapular entrapment neuropathy. A clinical, anatomical comparative study. Neurosurgery 1979;5:441-52.