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Spontaneous resolution of a spinoglenoid notch cyst and associated suprascapular nerve palsy: A case report
Spontaneous resolution of a spinoglenoid notch cyst and associated suprascapular nerve palsy: A case report Carrie M. Davidge, MD,a Richard Walker, MD,b Kelly Brett, MD,c and Richard S. Boorman, MD, MSc, FRCSC,d Calgary, Alberta, Canada
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ntrapment of the suprascapular nerve at the spinoglenoid notch and an associated denervation of the infraspinatus muscle were first recognized by Ganzhorn et al7 in 1981. Since that time, a compressive cyst in the spinoglenoid notch has become increasingly recognized as a common pathologic process behind this isolated neuropathy.1,15,16 Spinoglenoid notch cysts (SGNCs), also referred to as ganglion or paralabral cysts occupying the spinoglenoid notch, have a typical clinical presentation of posterior shoulder pain, isolated infraspinatus atrophy, and weakness to resisted external rotation.16 Patients may also have shoulder instability as a result of the superior and posterior labral pathology thought to be associated with these compressive lesions.15,16,19 Usually diagnosed by magnetic resonance imaging (MRI), symptomatic SGNCs are generally treated by open or arthroscopic surgical decompression of the cyst, because conservative treatment and needle aspiration are generally thought not to resolve symptoms or prevent recurrence over an extended period of time.4,16 Many case reports of SGNCs exist in the literature along with retrospective reviews of various treatments.1,3,5,16-18 An extremely limited number of these studies have indicated relief of symptoms with nonoperative treatment, and these potential resolutions were not confirmed by MRI.10,15,18 Here, we report what we believe to be the first MRI-documented spontaneous resolution of an SGNC and its associated suprascapular nerve palsy.
CASE REPORT A 31-year-old right hand– dominant professional video camera operator presented, complaining of 8 weeks of From the Departments of aSurgery and bRadiology, Faculty of Medicine, and dSport Medicine Centre, Faculty of Kinesiology, University of Calgary, and cSports Injury Clinic at Lindsay Park. There are no conflicts of interest regarding the individual authors’ commitments or project support for this case study. Reprint requests: Richard S. Boorman, MD, MSc, FRCSC, Heritage Medical Research Bldg, University of Calgary, 3330 Hospital Dr NW, Calgary, Alberta, Canada T2N 4N1 (E-mail: [email protected]). J Shoulder Elbow Surg 2007;16:e4-e7. Copyright © 2007 by Journal of Shoulder and Elbow Surgery Board of Trustees. 1058-2746/2007/$32.00 doi:10.1016/j.jse.2006.06.014
e4
persistent weakness and posterior pain in his left shoulder. He was otherwise healthy, denied any previous trauma to the shoulder, and reported no personal or family history of nerve entrapment or peripheral neuropathy. On examination, there was isolated atrophy of the infraspinatus and weakness to resisted external rotation of the symptomatic shoulder; findings for strength and range-of-motion testing were otherwise normal for both upper extremities. Positive signs of labral pathology were present in the affected shoulder. All deep tendon reflexes were grade 2 and symmetric; sensory pinprick and vibration testing findings were normal for both upper extremities. Upon further investigation, needle electromyography (EMG) testing indicated that the left supraspinatus and deltoid were normal whereas the infraspinatus showed 2⫹ fibrillations and positive sharp waves. A partial denervation isolated to the infraspinatus was present, and this involved significant axonal loss. There was no evidence of a diffuse process. Results indicated a left suprascapular neuropathy distal to the innervation of the supraspinatus muscle. MRI of the patient’s left shoulder was then performed 6 weeks after initial presentation to a physician. On imaging, a multiloculated cyst, measuring 4.0 ⫻ 2.0 cm, extended into the spinoglenoid notch and was associated with a superior labral tear. There was no evidence of extension into the suprascapular notch. Signal changes indicating partial denervation were isolated to the infraspinatus (Figure 1). After MRI and EMG diagnosis of an SGNC and suprascapular neuropathy isolated to the inferior branch of the nerve, the patient was referred for evaluation by an upper extremity orthopaedic specialist (R.S.B.). The patient was unable to attend the initial appointment and did not present for further assessment until 9 months after the initial development of symptoms. At that time, he reported that his symptoms had begun to resolve during the previous few months and that he now believed he had made a complete recovery. His assertions were consistent with physical examination findings: there was no obvious infraspinatus atrophy, no tenderness, and no weakness to external rotation of the previously affected shoulder. Furthermore, his shoulder tracked smoothly on examination, and there was no evidence of instability. His examination was unremarkable for any other shoulder pathology. The distal neurovascular status was intact for both upper extremities. This apparent resolution was confirmed by a magnetic resonance arthrogram obtained 10 months after the shoulder became symptomatic. The size of the paralabral cyst had decreased dramatically since the first examina-
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Davidge et al
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Figure 1 A and B, Axial T2* gradient echo images of the right shoulder demonstrate a superior labral tear (long arrow) and associated multiseptated paralabral cyst (short arrow) extending into the spinoglenoid notch. C and D, Coronal oblique fat-suppressed Turbo Spin Echo (TSE) T2-weighted images demonstrate the multiseptated paralabral cyst adjacent to the superior labrum (arrowhead). The normal low signal supraspinatus (SS) muscle should be noted. More posteriorly, the high signal intensity of the infraspinatus muscle (IS) due to denervation edema should be noted.
tion. Prior signs of infraspinatus denervation were absent, and the superior glenoid labral tear was still evident (Figure 2). The patient underwent strength testing approximately 24 months after making a full clinical recovery. The results showed only a 3% deficit in the power produced by the left-side external rotators compared with the right side. There was no endurance deficit between the left and
right sides. Quality of life was measured in conjunction with strength testing; the patient scored 98.52 of 100 on the Western Ontario Rotator Cuff Index and 100 of 100 on the American Shoulder and Elbow Surgeons Patient Assessment. He continues to have full function of the previously affected shoulder and has not had any subsequent pain or instability. Thus, according to MRI and clinical assessment, there was a spontaneous resolution
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J Shoulder Elbow Surg May/June 2007
Figure 2 A coronal oblique fat-suppressed TSE T1-weighted image (A) and fat-suppressed TSE T2-weighted image (B) from a follow-up magnetic resonance arthrogram demonstrate a significant interval decrease in the size of the multiseptated paralabral cyst (arrowheads) since the initial examination. C, A coronal oblique fat-suppressed TSE T2-weighted image shows interval resolution of the denervation edema in the infraspinatus (IS) muscle. D, An axial fat-suppressed TSE T2-weighted image demonstrates the small residual paralabral cyst (curved arrow) adjacent to the superior glenoid labral tear.
of the SGNC and the associated suprascapular nerve palsy.
DISCUSSION The suprascapular nerve passes along the upper border of the scapula, through the suprascapular notch, and enters the supraspinous fossa to innervate the supraspinatus muscle. As
the nerve branches inferiorly, it passes beneath the inferior transverse ligament and through the spinoglenoid notch to innervate the infraspinatus muscle.11,12 Pathologic processes affecting the proximal segment of the suprascapular nerve can present with significant rotator cuff weakness, because both the supraspinatus and infraspinatus muscles are affected. In contrast, patients with an SGNC and inferior suprascapular
Davidge et al
J Shoulder Elbow Surg Volume 16, Number 3
neuropathy tend to present with isolated infraspinatus atrophy and weakness to resisted external rotation.16 One of the main possible etiologies of periarticular cyst formation involves the leakage of synovial fluid via a 1-way valve at a weakened point in the joint capsule.2,6,14,19 This is particularly believed to be the case for meniscal cyst formation in the knee, where horizontal tears of the cartilage are thought to allow the escape of synovial fluid into surrounding tissues at high intra-articular joint pressures.6,9,14 In this case, the exiting fluid collects in the spinoglenoid notch, creating a mass effect on the suprascapular nerve. The overwhelming association between paralabral cysts and labral pathology appears to support this theory of periarticular cyst formation.15,16,19 Piatt et al16 identified 89% of MRI-documented SGNCs as having associated labral pathology. Similarly, in a retrospective investigation, Tirman et al19 found that all 20 patients with glenoid labral cysts had associated labral tears on MRI. All cysts that extended into both the spinoglenoid and suprascapular notches were associated with superior labrum anteriorposterior (SLAP) lesions, whereas cysts that extended only into the spinoglenoid notch were generally associated with posterior labral tears. In view of this strong association between labral pathology and SGNCs, treatment of these cysts usually involves open or arthroscopic decompression along with repair of labral pathology, especially in patients with recognized denervation of the infraspinatus due to suprascapular nerve entrapment. This type of management for SGNCs is based on numerous studies and case reports that have shown better relief and low rates of recurrence in patients receiving surgical treatment instead of conservative measures only.3,5,15,16 One notable exception is a retrospective review by Piatt et al,16 in which 17 of 30 patients receiving nonoperative treatment were satisfied with the outcome. This was in the form of either needle aspiration of the cyst or nonsteroidal anti-inflammatory drugs and physiotherapy. Two of these patients receiving conservative treatment had a spontaneous SGNC resolution documented by MRI, although these cases were not presented. However, it seems that none of these conservatively treated patients had an associated suprascapular nerve palsy. Only 28% of the 63 patients in the entire review had EMG and nerve conduction testing, and only 5 of these patients had abnormalities isolated to the infraspinatus on EMG testing. Furthermore, it appears that these particular patients with documented neuropathies received operative treatment. In the case of our patient, the most likely explanation for the SGNC formation was leakage of synovial fluid out through the SLAP tear and into adjacent tissues. The sensitivity of MRI in the detection of labral pathology ranges from 63%8,20 to 95%.12,13 In one study by Moore et al,15 SLAP lesions were observed intraoperatively in 11 of 12 patients with paralabral cysts and suprascapular neuropathy despite no preoperative MRI evidence of labral pathology. A spontaneous resolution of the SGNC and associated suprascapular nerve palsy is not necessarily in conflict with the 1-way valve theory of periarticular cyst formation. In our patient, the valve responsible for the SGNC formation may have closed spontaneously. Although a trial of conservative treatment may be indicated in patients with small SGNCs and no signs of suprascapular neuropathy, the literature overwhelmingly supports surgical treatment of these cysts along with labral repair, especially when a neuropathy is present. In presenting this case of an MRI-docu-
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mented spontaneous resolution of an SGNC and associated suprascapular nerve palsy in the presence of a superior labral tear, we propose that surgical treatment could be withheld if patients are showing signs of clinical recovery. However, it would clearly be very important that these patients be followed up closely and that further imaging or EMG/nerve conduction studies (or both) be performed if ongoing clinical recovery appears uncertain. REFERENCES
1. Antoniou J, Tae SK, Williams GR, Bird S, Ramsey ML, Iannotti JP. Suprascapular neuropathy: variability in the diagnosis, treatment, and outcome. Clin Orthop Relat Res 2001:131-8. 2. Barrie HJ. The pathogenesis and significance of meniscal cysts. J Bone Joint Surg Br 1979;61:184-9. 3. Chen AL, Ong BC, Rose DJ. Arthroscopic management of spinoglenoid cysts associated with SLAP lesions and suprascapular neuropathy. Arthroscopy 2003;19:E17-23. 4. Cummins CA, Messer TM, Nuber GW. Suprascapular nerve entrapment. J Bone Joint Surg Am 2000;82:415-24. 5. Fehrman DA, Orwin JF, Jennings RM. Suprascapular nerve entrapment by ganglion cysts: a report of six cases with arthroscopic findings and review of the literature. Arthroscopy 1995;11:727-34. 6. Ferrer-Roca O, Vilalta C. Lesions of the meniscus. Part II: horizontal cleavages and lateral cysts. Clin Orthop Relat Res 1980:301-7. 7. Ganzhorn RW, Hocker JT, Horowitz M, Switzer HE. Suprascapularnerve entrapment. J Bone Joint Surg Am 1981;63:492-4. 8. Garneau RA, Renfrew DL, Moore TE, el-Khoury GY, Nepola JV, Lemke JH. Glenoid labrum: evaluation with MR imaging. Radiology 1991;179:519-22. 9. Glasgow MM, Allen PW, Blakeway C. Arthroscopic treatment of cysts of the lateral meniscus. J Bone Joint Surg Br 1993;75:299302. 10. Hashimoto BE, Hayes AS, Ager JD. Sonographic diagnosis and treatment of ganglion cysts causing suprascapular nerve entrapment. J Ultrasound Med 1994;13:671-4. 11. Karatas GK, Gogus F. Suprascapular nerve entrapment in newsreel cameramen. Am J Phys Med Rehabil 2003;82:192-6. 12. Legan JM, Burkhard TK, Goff WB II, Balsara ZN, Martinez AJ, Burks DD, et al. Tears of the glenoid labrum: MR imaging of 88 arthroscopically confirmed cases. Radiology 1991;179:241-6. 13. McCauley TR, Pope CF, Jokl P. Normal and abnormal glenoid labrum: assessment with multiplanar gradient-echo MR imaging. Radiology 1992;183:35-7. 14. Mills CA, Henderson IJ. Cysts of the medial meniscus: arthroscopic diagnosis and management. J Bone Joint Surg Br 1993; 75:293-8. 15. Moore TP, Fritts HM, Quick DC, Buss DD. Suprascapular nerve entrapment caused by supraglenoid cyst compression. J Shoulder Elbow Surg 1997;6:455-62. 16. Piatt BE, Hawkins RJ, Fritz RC, Ho CP, Wolf E, Schickendantz M. Clinical evaluation and treatment of spinoglenoid notch ganglion cysts. J Shoulder Elbow Surg 2002;11:600-4. 17. Skirving AP, Kozak TK, Davis SJ. Infraspinatus paralysis due to spinoglenoid notch ganglion. J Bone Joint Surg Br 1994;76: 588-91. 18. Takagishi K, Saitoh A, Tonegawa M, Ikeda T, Itoman M. Isolated paralysis of the infraspinatus muscle. J Bone Joint Surg Br 1994; 76:584-7. 19. Tirman PF, Feller JF, Janzen DL, Peterfy CG, Bergman AG. Association of glenoid labral cysts with labral tears and glenohumeral instability: radiologic findings and clinical significance. Radiology 1994;190:653-8. 20. Yoneda M, Izawa K, Hirooka A, Hayashida K, Wakitani S. Indicators of superior glenoid labral detachment on magnetic resonance imaging and computed tomography arthrography. J Shoulder Elbow Surg 1998;7:2-12.
E
ntrapment of the suprascapular nerve at the spinoglenoid notch and an associated denervation of the infraspinatus muscle were first recognized by Ganzhorn et al7 in 1981. Since that time, a compressive cyst in the spinoglenoid notch has become increasingly recognized as a common pathologic process behind this isolated neuropathy.1,15,16 Spinoglenoid notch cysts (SGNCs), also referred to as ganglion or paralabral cysts occupying the spinoglenoid notch, have a typical clinical presentation of posterior shoulder pain, isolated infraspinatus atrophy, and weakness to resisted external rotation.16 Patients may also have shoulder instability as a result of the superior and posterior labral pathology thought to be associated with these compressive lesions.15,16,19 Usually diagnosed by magnetic resonance imaging (MRI), symptomatic SGNCs are generally treated by open or arthroscopic surgical decompression of the cyst, because conservative treatment and needle aspiration are generally thought not to resolve symptoms or prevent recurrence over an extended period of time.4,16 Many case reports of SGNCs exist in the literature along with retrospective reviews of various treatments.1,3,5,16-18 An extremely limited number of these studies have indicated relief of symptoms with nonoperative treatment, and these potential resolutions were not confirmed by MRI.10,15,18 Here, we report what we believe to be the first MRI-documented spontaneous resolution of an SGNC and its associated suprascapular nerve palsy.
CASE REPORT A 31-year-old right hand– dominant professional video camera operator presented, complaining of 8 weeks of From the Departments of aSurgery and bRadiology, Faculty of Medicine, and dSport Medicine Centre, Faculty of Kinesiology, University of Calgary, and cSports Injury Clinic at Lindsay Park. There are no conflicts of interest regarding the individual authors’ commitments or project support for this case study. Reprint requests: Richard S. Boorman, MD, MSc, FRCSC, Heritage Medical Research Bldg, University of Calgary, 3330 Hospital Dr NW, Calgary, Alberta, Canada T2N 4N1 (E-mail: [email protected]). J Shoulder Elbow Surg 2007;16:e4-e7. Copyright © 2007 by Journal of Shoulder and Elbow Surgery Board of Trustees. 1058-2746/2007/$32.00 doi:10.1016/j.jse.2006.06.014
e4
persistent weakness and posterior pain in his left shoulder. He was otherwise healthy, denied any previous trauma to the shoulder, and reported no personal or family history of nerve entrapment or peripheral neuropathy. On examination, there was isolated atrophy of the infraspinatus and weakness to resisted external rotation of the symptomatic shoulder; findings for strength and range-of-motion testing were otherwise normal for both upper extremities. Positive signs of labral pathology were present in the affected shoulder. All deep tendon reflexes were grade 2 and symmetric; sensory pinprick and vibration testing findings were normal for both upper extremities. Upon further investigation, needle electromyography (EMG) testing indicated that the left supraspinatus and deltoid were normal whereas the infraspinatus showed 2⫹ fibrillations and positive sharp waves. A partial denervation isolated to the infraspinatus was present, and this involved significant axonal loss. There was no evidence of a diffuse process. Results indicated a left suprascapular neuropathy distal to the innervation of the supraspinatus muscle. MRI of the patient’s left shoulder was then performed 6 weeks after initial presentation to a physician. On imaging, a multiloculated cyst, measuring 4.0 ⫻ 2.0 cm, extended into the spinoglenoid notch and was associated with a superior labral tear. There was no evidence of extension into the suprascapular notch. Signal changes indicating partial denervation were isolated to the infraspinatus (Figure 1). After MRI and EMG diagnosis of an SGNC and suprascapular neuropathy isolated to the inferior branch of the nerve, the patient was referred for evaluation by an upper extremity orthopaedic specialist (R.S.B.). The patient was unable to attend the initial appointment and did not present for further assessment until 9 months after the initial development of symptoms. At that time, he reported that his symptoms had begun to resolve during the previous few months and that he now believed he had made a complete recovery. His assertions were consistent with physical examination findings: there was no obvious infraspinatus atrophy, no tenderness, and no weakness to external rotation of the previously affected shoulder. Furthermore, his shoulder tracked smoothly on examination, and there was no evidence of instability. His examination was unremarkable for any other shoulder pathology. The distal neurovascular status was intact for both upper extremities. This apparent resolution was confirmed by a magnetic resonance arthrogram obtained 10 months after the shoulder became symptomatic. The size of the paralabral cyst had decreased dramatically since the first examina-
J Shoulder Elbow Surg Volume 16, Number 3
Davidge et al
e5
Figure 1 A and B, Axial T2* gradient echo images of the right shoulder demonstrate a superior labral tear (long arrow) and associated multiseptated paralabral cyst (short arrow) extending into the spinoglenoid notch. C and D, Coronal oblique fat-suppressed Turbo Spin Echo (TSE) T2-weighted images demonstrate the multiseptated paralabral cyst adjacent to the superior labrum (arrowhead). The normal low signal supraspinatus (SS) muscle should be noted. More posteriorly, the high signal intensity of the infraspinatus muscle (IS) due to denervation edema should be noted.
tion. Prior signs of infraspinatus denervation were absent, and the superior glenoid labral tear was still evident (Figure 2). The patient underwent strength testing approximately 24 months after making a full clinical recovery. The results showed only a 3% deficit in the power produced by the left-side external rotators compared with the right side. There was no endurance deficit between the left and
right sides. Quality of life was measured in conjunction with strength testing; the patient scored 98.52 of 100 on the Western Ontario Rotator Cuff Index and 100 of 100 on the American Shoulder and Elbow Surgeons Patient Assessment. He continues to have full function of the previously affected shoulder and has not had any subsequent pain or instability. Thus, according to MRI and clinical assessment, there was a spontaneous resolution
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Davidge et al
J Shoulder Elbow Surg May/June 2007
Figure 2 A coronal oblique fat-suppressed TSE T1-weighted image (A) and fat-suppressed TSE T2-weighted image (B) from a follow-up magnetic resonance arthrogram demonstrate a significant interval decrease in the size of the multiseptated paralabral cyst (arrowheads) since the initial examination. C, A coronal oblique fat-suppressed TSE T2-weighted image shows interval resolution of the denervation edema in the infraspinatus (IS) muscle. D, An axial fat-suppressed TSE T2-weighted image demonstrates the small residual paralabral cyst (curved arrow) adjacent to the superior glenoid labral tear.
of the SGNC and the associated suprascapular nerve palsy.
DISCUSSION The suprascapular nerve passes along the upper border of the scapula, through the suprascapular notch, and enters the supraspinous fossa to innervate the supraspinatus muscle. As
the nerve branches inferiorly, it passes beneath the inferior transverse ligament and through the spinoglenoid notch to innervate the infraspinatus muscle.11,12 Pathologic processes affecting the proximal segment of the suprascapular nerve can present with significant rotator cuff weakness, because both the supraspinatus and infraspinatus muscles are affected. In contrast, patients with an SGNC and inferior suprascapular
Davidge et al
J Shoulder Elbow Surg Volume 16, Number 3
neuropathy tend to present with isolated infraspinatus atrophy and weakness to resisted external rotation.16 One of the main possible etiologies of periarticular cyst formation involves the leakage of synovial fluid via a 1-way valve at a weakened point in the joint capsule.2,6,14,19 This is particularly believed to be the case for meniscal cyst formation in the knee, where horizontal tears of the cartilage are thought to allow the escape of synovial fluid into surrounding tissues at high intra-articular joint pressures.6,9,14 In this case, the exiting fluid collects in the spinoglenoid notch, creating a mass effect on the suprascapular nerve. The overwhelming association between paralabral cysts and labral pathology appears to support this theory of periarticular cyst formation.15,16,19 Piatt et al16 identified 89% of MRI-documented SGNCs as having associated labral pathology. Similarly, in a retrospective investigation, Tirman et al19 found that all 20 patients with glenoid labral cysts had associated labral tears on MRI. All cysts that extended into both the spinoglenoid and suprascapular notches were associated with superior labrum anteriorposterior (SLAP) lesions, whereas cysts that extended only into the spinoglenoid notch were generally associated with posterior labral tears. In view of this strong association between labral pathology and SGNCs, treatment of these cysts usually involves open or arthroscopic decompression along with repair of labral pathology, especially in patients with recognized denervation of the infraspinatus due to suprascapular nerve entrapment. This type of management for SGNCs is based on numerous studies and case reports that have shown better relief and low rates of recurrence in patients receiving surgical treatment instead of conservative measures only.3,5,15,16 One notable exception is a retrospective review by Piatt et al,16 in which 17 of 30 patients receiving nonoperative treatment were satisfied with the outcome. This was in the form of either needle aspiration of the cyst or nonsteroidal anti-inflammatory drugs and physiotherapy. Two of these patients receiving conservative treatment had a spontaneous SGNC resolution documented by MRI, although these cases were not presented. However, it seems that none of these conservatively treated patients had an associated suprascapular nerve palsy. Only 28% of the 63 patients in the entire review had EMG and nerve conduction testing, and only 5 of these patients had abnormalities isolated to the infraspinatus on EMG testing. Furthermore, it appears that these particular patients with documented neuropathies received operative treatment. In the case of our patient, the most likely explanation for the SGNC formation was leakage of synovial fluid out through the SLAP tear and into adjacent tissues. The sensitivity of MRI in the detection of labral pathology ranges from 63%8,20 to 95%.12,13 In one study by Moore et al,15 SLAP lesions were observed intraoperatively in 11 of 12 patients with paralabral cysts and suprascapular neuropathy despite no preoperative MRI evidence of labral pathology. A spontaneous resolution of the SGNC and associated suprascapular nerve palsy is not necessarily in conflict with the 1-way valve theory of periarticular cyst formation. In our patient, the valve responsible for the SGNC formation may have closed spontaneously. Although a trial of conservative treatment may be indicated in patients with small SGNCs and no signs of suprascapular neuropathy, the literature overwhelmingly supports surgical treatment of these cysts along with labral repair, especially when a neuropathy is present. In presenting this case of an MRI-docu-
e7
mented spontaneous resolution of an SGNC and associated suprascapular nerve palsy in the presence of a superior labral tear, we propose that surgical treatment could be withheld if patients are showing signs of clinical recovery. However, it would clearly be very important that these patients be followed up closely and that further imaging or EMG/nerve conduction studies (or both) be performed if ongoing clinical recovery appears uncertain. REFERENCES
1. Antoniou J, Tae SK, Williams GR, Bird S, Ramsey ML, Iannotti JP. Suprascapular neuropathy: variability in the diagnosis, treatment, and outcome. Clin Orthop Relat Res 2001:131-8. 2. Barrie HJ. The pathogenesis and significance of meniscal cysts. J Bone Joint Surg Br 1979;61:184-9. 3. Chen AL, Ong BC, Rose DJ. Arthroscopic management of spinoglenoid cysts associated with SLAP lesions and suprascapular neuropathy. Arthroscopy 2003;19:E17-23. 4. Cummins CA, Messer TM, Nuber GW. Suprascapular nerve entrapment. J Bone Joint Surg Am 2000;82:415-24. 5. Fehrman DA, Orwin JF, Jennings RM. Suprascapular nerve entrapment by ganglion cysts: a report of six cases with arthroscopic findings and review of the literature. Arthroscopy 1995;11:727-34. 6. Ferrer-Roca O, Vilalta C. Lesions of the meniscus. Part II: horizontal cleavages and lateral cysts. Clin Orthop Relat Res 1980:301-7. 7. Ganzhorn RW, Hocker JT, Horowitz M, Switzer HE. Suprascapularnerve entrapment. J Bone Joint Surg Am 1981;63:492-4. 8. Garneau RA, Renfrew DL, Moore TE, el-Khoury GY, Nepola JV, Lemke JH. Glenoid labrum: evaluation with MR imaging. Radiology 1991;179:519-22. 9. Glasgow MM, Allen PW, Blakeway C. Arthroscopic treatment of cysts of the lateral meniscus. J Bone Joint Surg Br 1993;75:299302. 10. Hashimoto BE, Hayes AS, Ager JD. Sonographic diagnosis and treatment of ganglion cysts causing suprascapular nerve entrapment. J Ultrasound Med 1994;13:671-4. 11. Karatas GK, Gogus F. Suprascapular nerve entrapment in newsreel cameramen. Am J Phys Med Rehabil 2003;82:192-6. 12. Legan JM, Burkhard TK, Goff WB II, Balsara ZN, Martinez AJ, Burks DD, et al. Tears of the glenoid labrum: MR imaging of 88 arthroscopically confirmed cases. Radiology 1991;179:241-6. 13. McCauley TR, Pope CF, Jokl P. Normal and abnormal glenoid labrum: assessment with multiplanar gradient-echo MR imaging. Radiology 1992;183:35-7. 14. Mills CA, Henderson IJ. Cysts of the medial meniscus: arthroscopic diagnosis and management. J Bone Joint Surg Br 1993; 75:293-8. 15. Moore TP, Fritts HM, Quick DC, Buss DD. Suprascapular nerve entrapment caused by supraglenoid cyst compression. J Shoulder Elbow Surg 1997;6:455-62. 16. Piatt BE, Hawkins RJ, Fritz RC, Ho CP, Wolf E, Schickendantz M. Clinical evaluation and treatment of spinoglenoid notch ganglion cysts. J Shoulder Elbow Surg 2002;11:600-4. 17. Skirving AP, Kozak TK, Davis SJ. Infraspinatus paralysis due to spinoglenoid notch ganglion. J Bone Joint Surg Br 1994;76: 588-91. 18. Takagishi K, Saitoh A, Tonegawa M, Ikeda T, Itoman M. Isolated paralysis of the infraspinatus muscle. J Bone Joint Surg Br 1994; 76:584-7. 19. Tirman PF, Feller JF, Janzen DL, Peterfy CG, Bergman AG. Association of glenoid labral cysts with labral tears and glenohumeral instability: radiologic findings and clinical significance. Radiology 1994;190:653-8. 20. Yoneda M, Izawa K, Hirooka A, Hayashida K, Wakitani S. Indicators of superior glenoid labral detachment on magnetic resonance imaging and computed tomography arthrography. J Shoulder Elbow Surg 1998;7:2-12.