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Clinical evaluation and treatment of spinoglenoid notch ganglion cysts
Clinical evaluation and treatment of spinoglenoid notch ganglion cysts Bruce E. Piatt, MD,c Richard J. Hawkins, MD, FRCS,a Russell C. Fritz, MD,d Charles P. Ho, MD,d Eugene Wolf, MD,b and Mark Schickendantz, MD,e Fargo, ND, Vail, Colo, Menlo Park, Calif, San Francisco, Calif, and Cleveland, Ohio
Spinoglenoid notch cysts were identified by magnetic resonance imaging in 73 patients. Posterosuperior labral tears were identified in 65 patients who had spinoglenoid notch cysts. Patient follow-up was available on 88% of patients at a mean of 20.5 months after treatment. There were 52 men and 11 women, with a mean age of 39 years (range, 19-76 years). All patients reported shoulder pain. Infraspinatus atrophy occurred in 25 patients, weakness with external rotation in 43, and posterior shoulder tenderness in 30. Nineteen patients underwent nonoperative management of the cyst (group I). Eleven underwent attempted needle aspiration of the cyst (group II). Six had isolated arthroscopic treatment of a labral defect with no cyst excision (group III). Twenty-seven were treated with surgical cyst excision with the cyst and superior labral tear fixed arthroscopically or with an open approach in various combinations (group IV). Of the patients, 53% were satisfied in group I, 64% in group II, 67% in group III, and 97% in group IV. (J Shoulder Elbow Surg 2002;11:600-4.)
scribed at the suprascapular notch.7,10 This condition was first described by Thompson and Kopell.14 Entrapment of the suprascapular nerve at this level usually causes denervation of both the supraspinatus and infraspinatus muscles. When cysts are present, nerve entrapment can occur as the suprascapular nerve traverses the lateral edge of the scapular spine in the spinoglenoid notch.1,2,7 This nerve entrapment may lead to pain and weakness of external rotation with isolated atrophy of the infraspinatus muscle. A hypertrophied inferior transverse scapular ligament can also cause entrapment in the spinoglenoid notch.5,11 Ganglions have recently been identified as the cause of shoulder pain and dysfunction through suprascapular nerve entrapment.6,13 The purpose of this study was to review the cases of patients with known ganglions in the spinoglenoid notch region as identified by MRI and to describe their symptoms, physical examination, and associated MRI findings. Patients’ outcomes from several treatment protocols were reviewed to help establish a treatment algorithm for a symptomatic spinoglenoid notch ganglion.
M agnetic resonance imaging (MRI) of the shoulder
MATERIALS AND METHODS
From the Steadman Hawkins Clinica and California Pacific Medical Center,b Vail, Coloa; Dakota Clinic, Fargo, NDc; Sand Hill Imaging Center, Menlo Park, Califd; and Horizon Orthopaedics, Cleveland, Ohioe. Presented at the Research from the Steadman Hawkins Sports Medicine Foundation Annual Meeting of the AOSSM Specialty Day, February 25, 1996, Atlanta, Ga. Reprint requests: Richard J. Hawkins, MD, Steadman Hawkins Sports Medicine Foundation, 181 W Meadow Dr, Suite 1000, Clinical Research, Vail, CO 81657 (E-mail: [email protected]). Copyright © 2002 by Journal of Shoulder and Elbow Surgery Board of Trustees. 1058-2746/2002/$35.00 ⫹ 0 32/1/127094 doi:10.1067/mse.2002.127094
Seventy-three patients from several orthopaedic practices had SGNCs diagnosed by MRI between 1989 and 1995. One of two musculoskeletal radiologists read the MRI scan to confirm the diagnosis. Of the 73 patients, 70 were referred to a musculoskeletal practice for MRI because of shoulder pain or weakness (or both), usually to rule out a rotator cuff tear. The remaining 3 were referred with a ganglion diagnosis. All patients underwent a chart review to identify symptoms and physical examination features, as well as treatment and outcome associated with the cyst. Ten were excluded because of insufficient follow-up data. The MRI findings of the 63 patients included in the study were then reviewed by 1 radiologist. MRI scans were evaluated for size and position of the SGNC and its extension, as well as any associated findings. Patients were categorized into 4 treatment groups for evaluating the outcome of treatment. Group I included patients who underwent nonoperative management of the cyst. The nonoperative treatment program consisted of physiotherapy and anti-inflammatory drugs. Group II included patients who underwent needle aspiration of the
is often used in the diagnosis of shoulder pain. Recently, MRI has identified ganglions about the shoulder with increasing frequency.3,12 Spinoglenoid notch cysts (SGNCs) may be implicated clinically if they cause compression of the suprascapular nerve. Suprascapular nerve entrapment has been de-
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J Shoulder Elbow Surg Volume 11, Number 6
cyst. Group III included patients who had isolated arthroscopic treatment of a labral defect with no cyst excision. Group IV included patients who were treated with open or arthroscopic surgical excision of the cyst, most of whom had fixation of the labral defect. Cysts were drained intraarticularly with blunt dissection, allowing ganglion fluid to extravasate into the joint. Subjective preoperative and postoperative data were collected including pain at rest, pain with overhead activities, and pain with activities of daily living. Use of nonsteroidal anti-inflammatory drugs and narcotics and patientreported loss of motion, atrophy, and history of trauma were recorded. All questions were documented as positive or negative. Objective data collected included presence and location of atrophy, tenderness, range of motion, impingement test results, and instability test results. At followup, patients were also asked if they were satisfied with their outcome. Descriptive statistical analysis was performed. Intergroup comparisons were performed with the 2 test for categorical variables and analysis of variance for continuous variables. Comparison between preoperative and postoperative parameters was performed with the paired t test. Statistical significance was established at P ⬍ .05.
RESULTS Follow-up data were obtained for 63 patients. The mean age was 39 years (range, 19-76 years). There were 52 men and 11 women. Fourteen cases were related to a workers compensation claim. The mean follow-up was 20.5 months with a range of 12 to 73 months. All patients had pain at the time of their initial examination. Preoperative pain was most evident during overhead activities and sports. Pain with activities of daily living or pain at rest was seen in 28 patients (46%). Weakness of the involved shoulder was present in 41 patients (65%), and 21 patients (33%) had a history of trauma. Nonsteroidal anti-inflammatory drugs were used by 37 patients (58%). Preoperative physical examination revealed 25 patients (40%) with infraspinatus muscle atrophy. Tenderness was found in 49 patients (78%), 30 of whom had posterior shoulder tenderness. The patients had normal range of motion in forward elevation, external rotation, abduction, and internal rotation. Weakness with external rotation was seen in 43 patients (68%). On the basis of physical examination and patient symptoms, patients were referred for MRI to evaluate the shoulder. Forty-eight patients (76%) were referred for possible rotator cuff tear. The remaining patients were referred for MRI to help diagnose the cause of the shoulder pain. Of the 48 patients with possible rotator cuff tear, 24 had positive impingement signs and pain with overhead activities on preoperative examination. Of the 24 patients with positive impingement signs, MRI identified 19 with superior la-
601
Table I MRI findings Findings Posterior superior labral tears Acromioclavicular abnormalities Infraspinatus atrophy Rotator cuff tear Supraspinatus atrophy Glenohumeral degenerative joint disease Posterior instability
No. of patients 56 23 18 7 6 3 1
bral pathology, 9 with acromioclavicular abnormalities, and 4 with rotator cuff tears. Four patients showed signs of instability on physical examination and were referred for labral pathology. All 4 had diagnoses of superior labral pathology confirmed by MRI, with no other rotator cuff or instability pathologies identified. Three patients were referred for possible cysts and 8 patients for shoulder pain from other pathologies. MRI demonstrated cysts and associated abnormalities (Table I). Of the 63 SGNCs, 28 (44%) had extension of the mass from the spinoglenoid notch into the supraspinatus fossa and 23 (37%) showed extension of the mass down into the infraspinatus fossa. An important finding was that 56 patients (89%) had associated superior labral pathology, usually described as degeneration, elevation, detachment, or discrete localized traumatic tears of the posterosuperior labral complex. On MRI, atrophy of the infraspinatus or supraspinatus muscle was demonstrated in 24 patients (38%). Eighteen patients (28%) underwent preoperative electromyography (EMG) studies. EMG demonstrated abnormalities of the infraspinatus muscle in 5 patients, the supraspinatus muscle in 5 patients, and both muscles in 4 patients, and no abnormalities were found in 4 patients. Of the 14 patients with abnormal EMG findings, 12 had pain with overhead activities, all had pain with sports, 11 had weakness, and 12 showed signs of clinical infraspinatus atrophy. These patients had fatty infiltration on MRI localized to the infraspinatus muscle. MRI evaluation of the 14 patients with abnormal EMG studies showed extension of the cyst into the supraspinatus fossa or infraspinatus fossa in 13 and superior labral pathology in 11. Group I
Group I comprised 19 patients who underwent nonoperative management of the cyst. The 2 patients who showed improvement of atrophy also had spontaneous resolution of the SGNC documented by MRI. Ten patients (53%) were satisfied with their outcome
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Group II
Group II comprised 11 patients who underwent needle aspiration of the cyst. Review of preoperative MRI was the only tool used to guide needle aspiration. At final follow-up, 5 patients had recurrent cyst formation as documented by return of symptoms and MRI evaluation. Seven patients (64%) were satisfied with their outcome after this treatment. Group II results are summarized in Figure 1, B. Group III
Group III comprised 6 patients who underwent isolated arthroscopic debridement or fixation of the posterosuperior labral tear with no treatment of the cyst. Four (67%) were satisfied with their outcome after treatment, all with relief of pain. Group IV
Figure 1 Subjective data at initial evaluation and follow-up for group I (nonoperative treatment) (A), group II (needle aspiration) (B), and group IV (surgical approach) (C). ADL, Activities of daily living; NSAIDS, nonsteroidal anti-inflammatory drugs.
after nonoperative treatment. Group I results are summarized in Figure 1, A.
Group IV comprised 27 patients who were treated with surgical excision of the cysts. Of these, 10 had both the cyst and fixation of the posterosuperior labral tear addressed arthroscopically and 10 underwent open excision of the cyst with no treatment of the labral defect. Seven patients underwent a combination of arthroscopic treatment of the posterosuperior labral tear and open excision of the SGNC. Of the 27 patients, 25 had labral pathology documented on MRI. The 2 patients with no labral pathology on MRI underwent open excision of the cyst. Patients’ subjective data are summarized in Figure 1, C. Twenty-six patients (96%) were satisfied with their treatment and had no pain at rest or with activities of daily living or sports. Of the 10 patients who had both the cyst decompressed and their posterosuperior labral tear addressed arthroscopically, all were satisfied and none had any pain at rest or with activities of daily living postoperatively. Of the 10 patients who underwent open excision of the cyst alone, 1 was unsatisfied with his outcome. All 7 patients who underwent a combination of open treatment of the cyst and arthroscopic repair of the labral defect were satisfied and had no pain at follow-up. Statistical analysis of the findings showed that group IV had a significantly higher proportion of satisfaction than the other groups. With regard to satisfaction, group IV results were statistically higher than those of group I (P ⫽ .001), group II (P ⫽ .019), and group III (P ⫽ .022). Statistical analysis of the findings showed that nonoperative treatment (groups I and II) resulted in a lower satisfaction rate (17/30) than surgical treatment (groups III and IV) (30/33) (P ⫽ .002).
Piatt et al
J Shoulder Elbow Surg Volume 11, Number 6
603
Figure 2 SGNC treatment algorithm.
DISCUSSION SGNCs have been identified by several authors.1,10,12,13 This large series of patients demonstrated SGNCs identified by MRI. These patients were seen, diagnosed, and treated from 1989 to 1995 when little was known about this pathologic entity. All patients had shoulder pain, and 41 patients (67%) had weakness. On initial physical examination, the most significant findings were infraspinatus atrophy in 25 patients (40%) and posterior shoulder tenderness in 30 (48%). MRI revealed a posterosuperior labral tear in almost all of the patients. This is consistent with the findings of Tirman et al.15 In a patient who is noted to have an SGNC, associated intra-articular labral pathology is common and should be considered in the his or her management. It has been suggested that the pathology for an SGNC relates to a ball-valve mechanism in which fluid leaks out of the joint through a superior labral defect, forms a cyst, and cannot get back into the joint or in which fluid continues to exude and the cyst continues to exist.9 Two patients had spontaneous resolution of their SGNCs, which was documented by MRI. Symptoms improved in both of these patients. If a 1-way ball-valve type mechanism causes the cysts, it may be possible for those cysts to disappear spontaneously. Initial diagnosis can be assisted by MRI and EMG. This information can then be used to make treatment decisions for the symptomatic patient. As an initial screening tool, EMG may be useful. Those patients with clinical atrophy and weakness showed infraspinatus wasting and fatty infiltration on MRI. MRI provides the ability to define the source of nerve entrapment at the spinoglenoid notch.
This study is limited by the fact that it was a retrospective review of patients treated by more than one surgeon. They were treated between 1989 and 1995 in different centers with similar but different preoperative and postoperative protocols. By reviewing all of these patients and their various treatments, as well as their different pathologies and treatment programs, we suggest the following (Figure 2): 1. If a cyst is minimally symptomatic, the patient is treated nonoperatively with nonsteroidal anti-inflammatory drugs and physical therapy. 2. If warranted by symptoms, one might initially attempt aspiration of the cyst. Unfortunately, recurrence of the cyst may occur.4,8 3. If aspiration fails, an arthroscopic approach may be attempted with intra-articular arthroscopic decompression by blunt dissection and suction, allowing the ganglion fluid to drain into the joint; if successful, then the posterior labral defect is repaired. If symptoms resolve, the treatment is considered to be successful. If arthroscopy is unable to decompress the cyst from within the joint, the labral lesion should be repaired arthroscopically and the following considered: 1. If the patient has pain only, one might determine whether the labral repair alone will resolve the patient’s pain. 2. If there is nerve compression with weakness, one should consider an open incision to the spinoglenoid notch to aspirate or resect the cyst. The nerve does not need to be defined or dissected.
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Piatt et al
Unfortunately, SGNCs may not be the only source of pain in a painful shoulder. There is also the glenoid labral defect to consider. There may also be other associated pathologies such as rotator cuff conditions, but if these are all ruled out and the cyst remains the problem, particularly in the presence of neurologic compression, then treatment of the cyst may be required. Spinoglenoid ganglion cysts can cause significant symptoms about the shoulder. On presentation, most patients will have pain and occasionally external rotation weakness. On physical examination, one should look for posterior shoulder tenderness, external rotation weakness, and infraspinatus atrophy. MRI confirms the diagnosis and defines the margins of the cyst. A posterosuperior labral tear was seen most frequently in this group of patients. The goal of the treatment is to resolve the patient’s symptoms, which can be accomplished by decompression of the cyst and repair of the labral tear. Preferably, this can be performed arthroscopically, but if unsuccessful, open excision of the cyst may be required. REFERENCES
1. Aiello I, Serra G, Traina GC, Tugnoli V. Entrapment of the suprascapular nerve at the spinoglenoid notch. Ann Neurol 1982;12:314-6. 2. Bigliani LU, Dalsey RM, McCann PD, April EW. An anatomical study of the suprascapular nerve. Arthroscopy 1990;6:301-5. 3. Catalano JB, Fenlin JM. Ganglion cysts about the shoulder girdle in the absence of suprascapular nerve involvement. J Shoulder Elbow Surg 1994;3:34-41.
J Shoulder Elbow Surg November/December 2002
4. Chiou HJ, Chou YH, Wu JJ, Hsu CC, Tiu CM, Chang CY, et al. Alternative and effective treatment of shoulder ganglion cyst: ultrasonographically guided aspiration. J Ultrasound Med 1999; 18:531-5. 5. Ferretti A, Cerullo G, Russo G. Suprascapular neuropathy in volleyball players. J Bone Joint Surg Am 1987;69:260-3. 6. Fritz RC, Helms CA, Steinbach LS, Genant HK. Suprascapular nerve entrapment: evaluation with MR imaging. Radiology 1992; 182:437-44. 7. Hama H, Ueba Y, Morinaga T, Suzuki K, Kuroki H, Yamamuro T. A new strategy for treatment of suprascapular entrapment neuropathy in athletes: shaving of the base of the scapular spine. J Shoulder Elbow Surg 1992;1:253-60. 8. Leitschuh PH, Bone CM, Bouska WM. Magnetic resonance imaging diagnosis, sonographically directed percutaneous aspiration, and arthroscopic treatment of a painful shoulder ganglion cyst associated with a SLAP lesion. Arthroscopy 1999;15:85-7. 9. Moore TP, Fritts HM, Quick DC, Buss DD. Suprascapular nerve entrapment caused by supraglenoid cyst compression. J Shoulder Elbow Surg 1997;6:455-62. 10. Neviaser TJ, Ain BR, Neviaser RJ. Suprascapular nerve denervation secondary to attenuation by a ganglionic cyst. J Bone Joint Surg Am 1986;68:627-8. 11. Post M, Grinblat E. Suprascapular nerve entrapment: diagnosis and results of treatment. J Shoulder Elbow Surg 1993;2:190-7. 12. Schickendantz M, Ho C. Suprascapular nerve compression by a ganglion cyst: diagnosis by magnetic resonance imaging. J Shoulder Elbow Surg 1993;2:110-4. 13. Skirving AP, Kozak TK, Davis SJ. Infraspinatus paralysis due to spinoglenoid notch ganglion. J Bone Joint Surg Br 1994;76:58891. 14. Thompson WAL, Kopell HP. Peripheral entrapment neuropathies of the upper extremity. New Engl J Med 1959;260:1261-5. 15. Tirman PF, Feller JF, Janzen DL, Peterfy CG, Bergman A. Association of glenoid labral cysts with labral tears and glenohumeral instability: radiologic findings and clinical significance. Radiology 1994;190:653-8.
Spinoglenoid notch cysts were identified by magnetic resonance imaging in 73 patients. Posterosuperior labral tears were identified in 65 patients who had spinoglenoid notch cysts. Patient follow-up was available on 88% of patients at a mean of 20.5 months after treatment. There were 52 men and 11 women, with a mean age of 39 years (range, 19-76 years). All patients reported shoulder pain. Infraspinatus atrophy occurred in 25 patients, weakness with external rotation in 43, and posterior shoulder tenderness in 30. Nineteen patients underwent nonoperative management of the cyst (group I). Eleven underwent attempted needle aspiration of the cyst (group II). Six had isolated arthroscopic treatment of a labral defect with no cyst excision (group III). Twenty-seven were treated with surgical cyst excision with the cyst and superior labral tear fixed arthroscopically or with an open approach in various combinations (group IV). Of the patients, 53% were satisfied in group I, 64% in group II, 67% in group III, and 97% in group IV. (J Shoulder Elbow Surg 2002;11:600-4.)
scribed at the suprascapular notch.7,10 This condition was first described by Thompson and Kopell.14 Entrapment of the suprascapular nerve at this level usually causes denervation of both the supraspinatus and infraspinatus muscles. When cysts are present, nerve entrapment can occur as the suprascapular nerve traverses the lateral edge of the scapular spine in the spinoglenoid notch.1,2,7 This nerve entrapment may lead to pain and weakness of external rotation with isolated atrophy of the infraspinatus muscle. A hypertrophied inferior transverse scapular ligament can also cause entrapment in the spinoglenoid notch.5,11 Ganglions have recently been identified as the cause of shoulder pain and dysfunction through suprascapular nerve entrapment.6,13 The purpose of this study was to review the cases of patients with known ganglions in the spinoglenoid notch region as identified by MRI and to describe their symptoms, physical examination, and associated MRI findings. Patients’ outcomes from several treatment protocols were reviewed to help establish a treatment algorithm for a symptomatic spinoglenoid notch ganglion.
M agnetic resonance imaging (MRI) of the shoulder
MATERIALS AND METHODS
From the Steadman Hawkins Clinica and California Pacific Medical Center,b Vail, Coloa; Dakota Clinic, Fargo, NDc; Sand Hill Imaging Center, Menlo Park, Califd; and Horizon Orthopaedics, Cleveland, Ohioe. Presented at the Research from the Steadman Hawkins Sports Medicine Foundation Annual Meeting of the AOSSM Specialty Day, February 25, 1996, Atlanta, Ga. Reprint requests: Richard J. Hawkins, MD, Steadman Hawkins Sports Medicine Foundation, 181 W Meadow Dr, Suite 1000, Clinical Research, Vail, CO 81657 (E-mail: [email protected]). Copyright © 2002 by Journal of Shoulder and Elbow Surgery Board of Trustees. 1058-2746/2002/$35.00 ⫹ 0 32/1/127094 doi:10.1067/mse.2002.127094
Seventy-three patients from several orthopaedic practices had SGNCs diagnosed by MRI between 1989 and 1995. One of two musculoskeletal radiologists read the MRI scan to confirm the diagnosis. Of the 73 patients, 70 were referred to a musculoskeletal practice for MRI because of shoulder pain or weakness (or both), usually to rule out a rotator cuff tear. The remaining 3 were referred with a ganglion diagnosis. All patients underwent a chart review to identify symptoms and physical examination features, as well as treatment and outcome associated with the cyst. Ten were excluded because of insufficient follow-up data. The MRI findings of the 63 patients included in the study were then reviewed by 1 radiologist. MRI scans were evaluated for size and position of the SGNC and its extension, as well as any associated findings. Patients were categorized into 4 treatment groups for evaluating the outcome of treatment. Group I included patients who underwent nonoperative management of the cyst. The nonoperative treatment program consisted of physiotherapy and anti-inflammatory drugs. Group II included patients who underwent needle aspiration of the
is often used in the diagnosis of shoulder pain. Recently, MRI has identified ganglions about the shoulder with increasing frequency.3,12 Spinoglenoid notch cysts (SGNCs) may be implicated clinically if they cause compression of the suprascapular nerve. Suprascapular nerve entrapment has been de-
600
Piatt et al
J Shoulder Elbow Surg Volume 11, Number 6
cyst. Group III included patients who had isolated arthroscopic treatment of a labral defect with no cyst excision. Group IV included patients who were treated with open or arthroscopic surgical excision of the cyst, most of whom had fixation of the labral defect. Cysts were drained intraarticularly with blunt dissection, allowing ganglion fluid to extravasate into the joint. Subjective preoperative and postoperative data were collected including pain at rest, pain with overhead activities, and pain with activities of daily living. Use of nonsteroidal anti-inflammatory drugs and narcotics and patientreported loss of motion, atrophy, and history of trauma were recorded. All questions were documented as positive or negative. Objective data collected included presence and location of atrophy, tenderness, range of motion, impingement test results, and instability test results. At followup, patients were also asked if they were satisfied with their outcome. Descriptive statistical analysis was performed. Intergroup comparisons were performed with the 2 test for categorical variables and analysis of variance for continuous variables. Comparison between preoperative and postoperative parameters was performed with the paired t test. Statistical significance was established at P ⬍ .05.
RESULTS Follow-up data were obtained for 63 patients. The mean age was 39 years (range, 19-76 years). There were 52 men and 11 women. Fourteen cases were related to a workers compensation claim. The mean follow-up was 20.5 months with a range of 12 to 73 months. All patients had pain at the time of their initial examination. Preoperative pain was most evident during overhead activities and sports. Pain with activities of daily living or pain at rest was seen in 28 patients (46%). Weakness of the involved shoulder was present in 41 patients (65%), and 21 patients (33%) had a history of trauma. Nonsteroidal anti-inflammatory drugs were used by 37 patients (58%). Preoperative physical examination revealed 25 patients (40%) with infraspinatus muscle atrophy. Tenderness was found in 49 patients (78%), 30 of whom had posterior shoulder tenderness. The patients had normal range of motion in forward elevation, external rotation, abduction, and internal rotation. Weakness with external rotation was seen in 43 patients (68%). On the basis of physical examination and patient symptoms, patients were referred for MRI to evaluate the shoulder. Forty-eight patients (76%) were referred for possible rotator cuff tear. The remaining patients were referred for MRI to help diagnose the cause of the shoulder pain. Of the 48 patients with possible rotator cuff tear, 24 had positive impingement signs and pain with overhead activities on preoperative examination. Of the 24 patients with positive impingement signs, MRI identified 19 with superior la-
601
Table I MRI findings Findings Posterior superior labral tears Acromioclavicular abnormalities Infraspinatus atrophy Rotator cuff tear Supraspinatus atrophy Glenohumeral degenerative joint disease Posterior instability
No. of patients 56 23 18 7 6 3 1
bral pathology, 9 with acromioclavicular abnormalities, and 4 with rotator cuff tears. Four patients showed signs of instability on physical examination and were referred for labral pathology. All 4 had diagnoses of superior labral pathology confirmed by MRI, with no other rotator cuff or instability pathologies identified. Three patients were referred for possible cysts and 8 patients for shoulder pain from other pathologies. MRI demonstrated cysts and associated abnormalities (Table I). Of the 63 SGNCs, 28 (44%) had extension of the mass from the spinoglenoid notch into the supraspinatus fossa and 23 (37%) showed extension of the mass down into the infraspinatus fossa. An important finding was that 56 patients (89%) had associated superior labral pathology, usually described as degeneration, elevation, detachment, or discrete localized traumatic tears of the posterosuperior labral complex. On MRI, atrophy of the infraspinatus or supraspinatus muscle was demonstrated in 24 patients (38%). Eighteen patients (28%) underwent preoperative electromyography (EMG) studies. EMG demonstrated abnormalities of the infraspinatus muscle in 5 patients, the supraspinatus muscle in 5 patients, and both muscles in 4 patients, and no abnormalities were found in 4 patients. Of the 14 patients with abnormal EMG findings, 12 had pain with overhead activities, all had pain with sports, 11 had weakness, and 12 showed signs of clinical infraspinatus atrophy. These patients had fatty infiltration on MRI localized to the infraspinatus muscle. MRI evaluation of the 14 patients with abnormal EMG studies showed extension of the cyst into the supraspinatus fossa or infraspinatus fossa in 13 and superior labral pathology in 11. Group I
Group I comprised 19 patients who underwent nonoperative management of the cyst. The 2 patients who showed improvement of atrophy also had spontaneous resolution of the SGNC documented by MRI. Ten patients (53%) were satisfied with their outcome
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Piatt et al
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Group II
Group II comprised 11 patients who underwent needle aspiration of the cyst. Review of preoperative MRI was the only tool used to guide needle aspiration. At final follow-up, 5 patients had recurrent cyst formation as documented by return of symptoms and MRI evaluation. Seven patients (64%) were satisfied with their outcome after this treatment. Group II results are summarized in Figure 1, B. Group III
Group III comprised 6 patients who underwent isolated arthroscopic debridement or fixation of the posterosuperior labral tear with no treatment of the cyst. Four (67%) were satisfied with their outcome after treatment, all with relief of pain. Group IV
Figure 1 Subjective data at initial evaluation and follow-up for group I (nonoperative treatment) (A), group II (needle aspiration) (B), and group IV (surgical approach) (C). ADL, Activities of daily living; NSAIDS, nonsteroidal anti-inflammatory drugs.
after nonoperative treatment. Group I results are summarized in Figure 1, A.
Group IV comprised 27 patients who were treated with surgical excision of the cysts. Of these, 10 had both the cyst and fixation of the posterosuperior labral tear addressed arthroscopically and 10 underwent open excision of the cyst with no treatment of the labral defect. Seven patients underwent a combination of arthroscopic treatment of the posterosuperior labral tear and open excision of the SGNC. Of the 27 patients, 25 had labral pathology documented on MRI. The 2 patients with no labral pathology on MRI underwent open excision of the cyst. Patients’ subjective data are summarized in Figure 1, C. Twenty-six patients (96%) were satisfied with their treatment and had no pain at rest or with activities of daily living or sports. Of the 10 patients who had both the cyst decompressed and their posterosuperior labral tear addressed arthroscopically, all were satisfied and none had any pain at rest or with activities of daily living postoperatively. Of the 10 patients who underwent open excision of the cyst alone, 1 was unsatisfied with his outcome. All 7 patients who underwent a combination of open treatment of the cyst and arthroscopic repair of the labral defect were satisfied and had no pain at follow-up. Statistical analysis of the findings showed that group IV had a significantly higher proportion of satisfaction than the other groups. With regard to satisfaction, group IV results were statistically higher than those of group I (P ⫽ .001), group II (P ⫽ .019), and group III (P ⫽ .022). Statistical analysis of the findings showed that nonoperative treatment (groups I and II) resulted in a lower satisfaction rate (17/30) than surgical treatment (groups III and IV) (30/33) (P ⫽ .002).
Piatt et al
J Shoulder Elbow Surg Volume 11, Number 6
603
Figure 2 SGNC treatment algorithm.
DISCUSSION SGNCs have been identified by several authors.1,10,12,13 This large series of patients demonstrated SGNCs identified by MRI. These patients were seen, diagnosed, and treated from 1989 to 1995 when little was known about this pathologic entity. All patients had shoulder pain, and 41 patients (67%) had weakness. On initial physical examination, the most significant findings were infraspinatus atrophy in 25 patients (40%) and posterior shoulder tenderness in 30 (48%). MRI revealed a posterosuperior labral tear in almost all of the patients. This is consistent with the findings of Tirman et al.15 In a patient who is noted to have an SGNC, associated intra-articular labral pathology is common and should be considered in the his or her management. It has been suggested that the pathology for an SGNC relates to a ball-valve mechanism in which fluid leaks out of the joint through a superior labral defect, forms a cyst, and cannot get back into the joint or in which fluid continues to exude and the cyst continues to exist.9 Two patients had spontaneous resolution of their SGNCs, which was documented by MRI. Symptoms improved in both of these patients. If a 1-way ball-valve type mechanism causes the cysts, it may be possible for those cysts to disappear spontaneously. Initial diagnosis can be assisted by MRI and EMG. This information can then be used to make treatment decisions for the symptomatic patient. As an initial screening tool, EMG may be useful. Those patients with clinical atrophy and weakness showed infraspinatus wasting and fatty infiltration on MRI. MRI provides the ability to define the source of nerve entrapment at the spinoglenoid notch.
This study is limited by the fact that it was a retrospective review of patients treated by more than one surgeon. They were treated between 1989 and 1995 in different centers with similar but different preoperative and postoperative protocols. By reviewing all of these patients and their various treatments, as well as their different pathologies and treatment programs, we suggest the following (Figure 2): 1. If a cyst is minimally symptomatic, the patient is treated nonoperatively with nonsteroidal anti-inflammatory drugs and physical therapy. 2. If warranted by symptoms, one might initially attempt aspiration of the cyst. Unfortunately, recurrence of the cyst may occur.4,8 3. If aspiration fails, an arthroscopic approach may be attempted with intra-articular arthroscopic decompression by blunt dissection and suction, allowing the ganglion fluid to drain into the joint; if successful, then the posterior labral defect is repaired. If symptoms resolve, the treatment is considered to be successful. If arthroscopy is unable to decompress the cyst from within the joint, the labral lesion should be repaired arthroscopically and the following considered: 1. If the patient has pain only, one might determine whether the labral repair alone will resolve the patient’s pain. 2. If there is nerve compression with weakness, one should consider an open incision to the spinoglenoid notch to aspirate or resect the cyst. The nerve does not need to be defined or dissected.
604
Piatt et al
Unfortunately, SGNCs may not be the only source of pain in a painful shoulder. There is also the glenoid labral defect to consider. There may also be other associated pathologies such as rotator cuff conditions, but if these are all ruled out and the cyst remains the problem, particularly in the presence of neurologic compression, then treatment of the cyst may be required. Spinoglenoid ganglion cysts can cause significant symptoms about the shoulder. On presentation, most patients will have pain and occasionally external rotation weakness. On physical examination, one should look for posterior shoulder tenderness, external rotation weakness, and infraspinatus atrophy. MRI confirms the diagnosis and defines the margins of the cyst. A posterosuperior labral tear was seen most frequently in this group of patients. The goal of the treatment is to resolve the patient’s symptoms, which can be accomplished by decompression of the cyst and repair of the labral tear. Preferably, this can be performed arthroscopically, but if unsuccessful, open excision of the cyst may be required. REFERENCES
1. Aiello I, Serra G, Traina GC, Tugnoli V. Entrapment of the suprascapular nerve at the spinoglenoid notch. Ann Neurol 1982;12:314-6. 2. Bigliani LU, Dalsey RM, McCann PD, April EW. An anatomical study of the suprascapular nerve. Arthroscopy 1990;6:301-5. 3. Catalano JB, Fenlin JM. Ganglion cysts about the shoulder girdle in the absence of suprascapular nerve involvement. J Shoulder Elbow Surg 1994;3:34-41.
J Shoulder Elbow Surg November/December 2002
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