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Suprascapular Nerve Palsy Secondary to Spinoglenoid Cysts: Results of Arthroscopic Treatment
Suprascapular Nerve Palsy Secondary to Spinoglenoid Cysts: Results of Arthroscopic Treatment Kenneth J. Westerheide, M.D., Ryan M. Dopirak, M.D., Ronald P. Karzel, M.D., and Stephen J. Snyder, M.D.
Purpose: The purpose of this study was to investigate the results of arthroscopic treatment in 14 patients with suprascapular nerve palsy secondary to spinoglenoid ganglion cysts. Methods: Fourteen patients underwent arthroscopic decompression of ganglion cysts associated with suprascapular neuropathy. The most common presenting symptoms were pain and weakness, which lasted an average of 7.5 months. Ten of 14 patients were noted on examination to have atrophy, and all 14 patients had weakness of the infraspinatus. Magnetic resonance imaging (MRI) showed spinoglenoid ganglion cysts in all 14 patients; average cyst size was 3 cm. MRI revealed labral pathology in 12 of 14 cases; labral pathology was identified intraoperatively in all 14 patients. Results: Postoperatively, the average Simple Shoulder Test (SST) score was 11.5 (12 maximum), which was improved from an estimated preoperative score of 4.3. Improvement in external rotation strength was seen in 100% of patients who were examined postoperatively. No patients were taking pain medicine at latest follow-up. No complications were reported, and there were no clinical or symptomatic recurrences at an average follow-up of 51 months. Conclusions: Arthroscopic treatment of patients with spinoglenoid ganglion cysts is safe and effective, resulting in good clinical outcomes. In our study of 14 patients, no recurrences were seen at an average of 51 months of follow-up. Level of Evidence: Level IV, therapeutic case series. Key Words: Arthroscopic—Ganglion—Glenoid labrum—Suprascapular neuropathy.
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anglion cysts of the shoulder are a relatively rare cause of shoulder pain. However, they often present with many of the same symptoms associated with more common conditions, making diagnosis difficult at times.1,2 To make an accurate diagnosis and implement an appropriate treatment plan, one must be aware of this uncommon cause of shoulder pain. Magnetic resonance imaging (MRI) and electromyography (EMG) are useful diagnostic tools in patients with suspected paralabral ganglion cysts and/or suprascap-
From Mount Carmel Health System (K.J.W.), Columbus, Ohio; and Southern California Orthopedic Institute, Medical Education (R.M.D., R.P.K., S.J.S.), Van Nuys, California, U.S.A. Address correspondence and reprint requests to Ryan M. Dopirak, M.D., Southern California Orthopedic Institute, Medical Education, 6815 Noble Avenue, Van Nuys, CA, U.S.A. E-mail: [email protected] © 2006 by the Arthroscopy Association of North America 0749-8063/06/2207-5239$32.00/0 doi:10.1016/j.arthro.2006.03.019
ular neuropathy. MRI accurately shows the size and location of ganglions—information that is critical for planning surgical intervention.3-5 It has also shown the frequent association of labral pathology with ganglion cysts.5-7 Although MRI can detect atrophy of the supraspinatus and infraspinatus,3,5 the diagnosis of suprascapular neuropathy can be confirmed only by EMG/ nerve conduction velocity (NCV) because the presence of a cyst does not necessarily mean that pathologic nerve compression is present.1,6,8-13 When ordering an EMG, one should specifically request evaluation of the suprascapular nerve because this may not be included as part of a routine upper extremity EMG. Many treatment options exist for patients with symptomatic paralabral ganglion cysts and suprascapular nerve compression. Initial treatment is typically nonoperative. For patients in whom a trial of conservative therapy is not effective, surgical intervention is considered. Traditionally, this disorder has been treated with open cyst excision. However, an open
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approach does not enable the surgeon to assess and treat labral pathology, which may predispose to recurrence of the cyst. In recent years, numerous authors have developed arthroscopic techniques designed to decompress spinoglenoid cysts and concomitantly address labral pathology, which is present in a large percentage of these patients.2,6,7,14-19 The purpose of this study was to report the results of arthroscopic treatment of 14 patients with suprascapular nerve palsy secondary to spinoglenoid ganglion cysts. Our hypothesis was that arthroscopic treatment of spinoglenoid ganglion cysts that cause suprascapular neuropathy and concomitant labral pathology results in good outcomes and low rates of clinical recurrence. METHODS Between 1996 and 2001, 14 patients underwent arthroscopic decompression of ganglion cysts associated with suprascapular nerve palsy. Two surgeons were involved in this study, both of whom had extensive experience in shoulder arthroscopy. All patients were treated at the same institution. A retrospective chart review was performed for all patients. Data collected included presenting symptoms, physical examination findings, MRI evaluation, EMG results, intraoperative findings, and details of arthroscopic treatment. Twelve of the 14 patients returned for follow-up and were evaluated by history and physical examination. The remaining 2 patients were evaluated by mail survey or telephone interview. Outcomes were measured with the Constant-Murley Score, the Simple Shoulder Test (SST), and the Hawkins Shoulder Evaluation Form. Average patient age was 41 years (range, 27 to 63 years). Ten of 14 patients participated in recreational athletics. No high-level athletes were included in this study. In 6 of 14 patients, shoulder pathology was considered work related. In 12 of 14 patients, the dominant extremity was involved. All 14 patients presented with reports of shoulder pain. In 7 patients, the pain was radiating. Five patients described night pain. In 8 patients, pain was exacerbated by reaching or raising the arm. Two patients reported exacerbation of pain with simple use or motion of the arm. In 10 of 14 patients, atrophy was noted on examination. Preoperatively, all 14 patients had weakness of the infraspinatus muscle. External rotation strength was 4/5 in 11 patients, 3/5 in 2 patients, and 1/5 in 1 patient. Muscle strength was tested manually. The exact type and duration of nonoperative treatment varied in our study population because many
patients had received treatment before they were referred to our institution. Nonoperative treatment typically consisted of rest, ice, nonsteroidal anti-inflammatory drugs (NSAIDs), physical therapy (PT), and/or cortisone injections. Average time from onset of symptoms to surgery was 7.5 months. One patient underwent previous open cyst excision. All 14 patients had a preoperative MRI. Spinoglenoid ganglion cysts were seen in all 14 patients; average cyst size was 3 cm. Infraspinatus signal change was noted in 8 of 14 cases. Labral pathology was present in 12 of 14 cases. Eleven patients had EMGs preoperatively; all were positive for denervation of the infraspinatus. Because of the retrospective nature of this study, EMGs were not obtained in all 14 patients. Assessment of statistical correlation between degree of denervation and postoperative outcome was not feasible due to our small sample size. This was not feasible because of our small sample size. Arthroscopic Technique A complete 15-point diagnostic examination of the glenohumeral joint is performed, with particular attention paid to the superior labrum. If a SLAP lesion (Fig 1) or posterior labral detachment is found, the cyst may sometimes be decompressed through this lesion. If the labrum is well attached, an electrosurgical device or shaver is used to create a 1-cm capsulotomy at the posterior superior glenoid rim. The exact location of the capsulotomy is based on the anatomic location of
FIGURE 1. Arthroscopic picture of large type II SLAP lesion with extension of tear into posterior superior labrum. A thorough and complete diagnostic arthroscopy is mandatory in all patients with symptomatic spinoglenoid ganglion cysts because concomitant labral disease is very common. The patient is in the lateral decubitus position with an arthroscope in the posterior portal (left shoulder).
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FIGURE 2. (A) Axial, (B) coronal oblique, and (C) sagittal oblique T2-weighted MRIs of a spinoglenoid ganglion cyst.
the ganglion, which is determined from the preoperative MRI scan (Fig 2). With the arthroscope in the posterior portal, a blunt dissecting tool is used to develop and probe the capsulotomy until the cyst is located. A characteristic amber-colored fluid will be encountered when the cyst is entered. This fluid should be seen in most patients with large paralabral cysts if the capsulotomy has been placed in the correct anatomic location. After the cyst has been identified, an arthroscopic shaver is placed within the cyst, the fluid is evacuated with suction, and the cyst wall is removed (Fig 3). The shaver is kept pointed at the glenoid neck at all times. So that damage to the suprascapular nerve can be avoided, no attempt is made to remove the capsule from the area about the spine of the scapula. Dissection should not extend beyond 1 cm medial to the posterior superior labral attachment to the glenoid; in
this way, the nerve is avoided as it courses through the spinoglenoid notch. Dissection should not extend beyond 1 cm medial to the posterior superior labral attachment to the glenoid, as anatomic studies have shown that the distance from the posterior glenoid rim to the suprascapular nerve or its branches is approximately 1.8 to 2.1 cm.20,21 The arthroscope is next moved to the anterior portal, and the shaver is introduced through the posterior portal. With the shaver again directed at the glenoid neck, the capsulotomy is further developed to remove the posterior portion of the cyst. It should again be stressed that dissection should be carried no farther than 1 cm medial to the glenoid so that iatrogenic injury to the suprascapular nerve can be avoided. It is possible that a small residual portion of the cyst wall may present more medially toward the scapular spine. However, this is clini-
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K. J. WESTERHEIDE ET AL. underwent subacromial decompression; 1 of these 2 patients also had a distal clavicle excision. RESULTS
FIGURE 3. Characteristic appearance of amber-colored, gelatinous material within a paraglenoid ganglion cyst.
cally insignificant because the offending lesion has been adequately decompressed. After the cyst has been removed, remaining intraarticular pathology is addressed. This includes debridement of type I SLAP lesions, as well as repair of type II SLAP lesions with the single anchor– double suture (SADS) technique22 (Fig 4). Occasionally, the posterior superior labrum “peel back” phenomenon as described by Burkart and Morgan23 is present and may require stabilization with a single loaded anchor placed posteriorly. Postoperative rehabilitation varies according to the treatment rendered. If labral debridement is performed without formal SLAP repair, patients will use a sling for comfort for a limited time. Full return to activities is often possible within 6 weeks. If posterior labral repair or SLAP repair is performed, the patient is supported in an UltraSling (DJ Orthopedics, Carlsbad, CA) for approximately 3 weeks. Elbow, wrist, and hand exercises, along with gentle pendulum exercises, are begun during the first week. Active range-of-motion exercises are started at 3 weeks. Biceps strengthening is delayed until 6 weeks postoperatively. Full activities are resumed when motion and strength are normal, usually about 4 months postoperatively. All 14 patients in this study underwent shoulder arthroscopy with spinoglenoid cyst decompression. Labral pathology was identified in all 14 patients. Labral repair was performed in patients with type II SLAP lesions, posterior superior labral tears, and/or posterior Bankart lesions (7 patients). Debridement alone was performed in patients with type I SLAP tears and/or degenerative fraying of the posterior labrum (7 patients). Two patients
Average patient follow-up in this study was 51 months (range, 24 to 73 months). Postoperatively, external rotation strength was 5/5 in 10 patients and 4/5 in 2 patients. Postoperative external rotation strength was improved in all 12 patients, as compared with preoperative external rotation strength. The average Constant-Murley score was 94 (100 maximum) postoperatively. The average SST score was 11.5 (12 maximum), which was improved from an estimated preoperative SST score of 4.3. As compared with preoperative activity level, 8 patients rated their activity as unchanged postoperatively; 4 patients rated their activity as improved, and 2 patients rated their activity as slightly diminished. No patients were currently taking pain medicine at latest follow-up. The average overall satisfaction score was 1.5 (range, 1 to 13), where 1 indicated that the patient was fully satisfied and 13 meant that outcomes were unsatisfactory. No complications were reported, and there were no clinical or symptomatic recurrences. DISCUSSION The suprascapular nerve travels below the superior transverse scapular ligament as it passes through the suprascapular notch. The space available for the su-
FIGURE 4. Repair of type II SLAP lesion in the left shoulder. Adequate treatment of concomitant labral disease is necessary to prevent recurrent ganglion cyst formation. The patient is in the lateral decubitus position with an arthroscope in the posterior portal (same patient as in Fig 1).
ARTHROSCOPY FOR SUPRASCAPULAR NERVE PALSY prascapular nerve at this location depends on the shape of the suprascapular notch and the size and structure of the transverse scapular ligament.24,25 After providing innervation to the supraspinatus, the nerve continues around the scapular spine through the spinoglenoid notch. At this location, it is relatively constrained by the inferior transverse scapular ligament, or the spinoglenoid ligament. After passing through the spinoglenoid notch, the nerve terminates by giving 2 to 4 motor branches to the infraspinatus13,21,24 (Fig 5). The suprascapular nerve is susceptible to injury at both the suprascapular notch and the spinoglenoid notch.26,27 Proximal insult leads to weakness of both the supraspinatus and the infraspinatus, whereas distal insult leads to isolated infraspinatus weakness. Suprascapular neuropathy may result from injuries involving excessive traction or compression. Traction injuries most commonly occur at the suprascapular notch because of the variable shape of the notch and the tethering effect of the transverse scapular ligament.2,28 However, traction injuries may also occur at the spinoglenoid notch, especially in patients involved in repetitive overhead athletic activities.2,29,30 The focus of this study is suprascapular neuropathy secondary to direct compression by a ganglion cyst. Extrinsic compression by a ganglion cyst occurs most
FIGURE 5. Anatomy of the suprascapular nerve. (Reprinted with permission from Orthop Clin North Am 2003;34:522.)
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commonly at the spinoglenoid notch.2 It is postulated that a thickened spinoglenoid ligament may amplify the deleterious effects of a ganglion on the suprascapular nerve31 in that it may further diminish the space available for the nerve. However, this is not known with certainty because the prevalence and the morphology of the spinoglenoid ligament have been reported with wide variability.24,26,31-36 Initial treatment for patients with symptomatic ganglion cysts of the shoulder should be nonoperative. Patients should be advised to avoid repetitive overhead activities, as well as other actions that aggravate the condition. A physical therapy program should be prescribed that improves flexibility and strengthens the scapular stabilizers, as well as the rotator cuff muscles. It is possible for cysts to spontaneously resolve. Piatt et al.19 documented this on MRI in 2 patients, both of whom experienced subsequent improvement of their symptoms. However, these patients should be monitored closely for signs of clinical deterioration because it is possible for the cysts to become larger. For patients who fail to respond to conservative measures, a variety of treatment options exist. Imageguided aspiration performed with ultrasound, computed tomography (CT), or MRI has been reported with mixed results. Piatt et al.19 performed needle aspiration of spinoglenoid cysts in 11 patients. At final evaluation, 5 patients were found to have recurrent cyst formation documented on MRI. Tung et al.37 reported that 3 of 4 patients who underwent cyst aspiration showed recurrence at 4 months. The primary disadvantage of aspiration as the sole treatment modality is its inability to assess and treat patients with intra-articular pathology, which may predispose to recurrence of the ganglion cyst. Surgical options for the treatment of patients with ganglion cysts of the shoulder include both open and arthroscopic techniques. Traditionally, the open posterior approach for decompression of spinoglenoid cysts has been used with success. The advantage of an open decompression is direct visualization of the cyst and suprascapular nerve. However, one disadvantage is the potential morbidity associated with the surgical approach, which entails deltoid detachment or splitting. Additionally, an open approach does not enable the surgeon to assess and treat labral pathology, which may ultimately predispose to recurrence of the cyst. The combination of arthroscopy to address labral pathology and aspiration or open cyst excision is also an option. However, arthroscopic treatment alone has shown good success in limited case series and avoids
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the potential morbidity of open decompression.2,6,14,15,17,18 Appropriate treatment of labral pathology combined with decompression of the spinoglenoid ganglion cyst typically provides good clinical outcomes and low rates of recurrence.6,14,16-19 Iannotti17 presented 3 patients treated all-arthroscopically with a posterior superior capsulotomy. At 1 year, no recurrences were seen on MRI, and all patients had complete relief of pain and return of external rotation strength. Chen et al.14 reported 3 patients with suprascapular neuropathy secondary to cyst compression at the spinoglenoid notch. All 3 patients were treated with arthroscopic cyst decompression and SLAP repair. Postoperative EMG and MRI showed return of nerve function and cyst resolution. Fehrman et al.16 studied 6 patients with suprascapular nerve compression secondary to a ganglion cyst. All 6 also had arthroscopically confirmed posterior capsulolabral injuries. Treatment consisted of a combination of arthroscopic and open methods. Postoperatively, 5 of 6 patients reported complete resolution of pain. The single remaining patient reported improvement in pain but not complete resolution. Lichtenberg et al.18 evaluated 8 patients with suprascapular neuropathy secondary to spinoglenoid notch ganglion cysts. All patients were examined arthroscopically; 6 were found to have SLAP lesions. Arthroscopic cyst decompression was performed in all patients. Formal repair was performed in the 6 patients with SLAP lesions. In the 2 patients without identifiable labral pathology, a capsulotomy was performed and left open. All patients improved in terms of pain, strength, and function. Piatt et al.19 evaluated 73 patients with symptomatic spinoglenoid notch ganglion cysts. Multiple treatment modalities were employed, including nonoperative treatment and needle aspiration, as well as various combinations of arthroscopic and open surgical approaches to treatment of labral pathology and ganglion cysts. In 10 patients, cyst decompression and treatment of labral pathology were performed all-arthroscopically. Postoperatively, all 10 patients were satisfied, and none reported any pain at rest or with activities of daily living. In our study of 14 patients treated all-arthroscopically, the average postoperative SST score was 11.5 (12 maximum). The average satisfaction score was 1.5 (1, complete satisfaction; 13, unsatisfactory). Of patients who were examined postoperatively, 100% showed improvement in external rotation strength. No clinical or symptomatic recurrences occurred.
This study is limited by the fact that it is a retrospective case series with no control group. Postoperative outcomes were quantified, but preoperative shoulder scores were not calculated or were simply estimated. This makes accurate quantification of patient improvement difficult. Additionally, the disease encountered within our patient population was variable. As a result, treatment was not identical for each patient. Although no clinical or symptomatic recurrences occurred, postoperative MRIs were not obtained to confirm cyst resolution. This would have provided a more definitive method of evaluating recurrences, but it was financially impractical. Our technique involves treatment of labral pathology and direct removal of the cyst. It is not known with certainty whether simply addressing the labral pathology alone would lead to cyst resolution. This would offer the potential benefit of minimizing the risk of iatrogenic injury to the suprascapular nerve. Further study is warranted. In conclusion, arthroscopic treatment of patients with spinoglenoid ganglion cysts is safe and effective, resulting in good clinical outcomes. In our study of 14 patients, no recurrences were reported at an average of 51 months’ follow-up.
REFERENCES 1. Drez D Jr. Suprascapular neuropathy in the differential diagnosis of rotator cuff injuries. Am J Sports Med 1976;4:43-45. 2. Romeo AA, Rotenberg D, Bach BR Jr. Suprascapular neuropathy. J Am Acad Orthop Surg 1999;7:358-367. 3. Fritz RC, Helms CA, Steinbach LS, et al. Suprascapular nerve entrapment. Evaluation with MR imaging. Radiology 1992; 182:437-444. 4. Goss TP, Aronow MS, Coumas JM. The use of MRI to diagnose suprascapular nerve entrapment caused by a ganglion. Orthopedics 1994;17:359-362. 5. Herzog RJ. Magnetic resonance imaging of the shoulder. Instr Course Lect 1998;47:3-20. 6. Moore TP, Fritts HM, Quick DC, et al. Suprascapular nerve entrapment caused by supraglenoid cyst compression. J Shoulder Elbow Surg 1997;6:455-462. 7. Tirman PFJ, Feller JF, Janzen DL, et al. Association of glenoid labral cysts with labral tears and glenohumeral instability. Radiologic findings and clinical significance. Radiology 1994; 190:653-658. 8. Hadley MN, Sonntag VK, Pittman HW. Suprascapular nerve entrapment: A summary of seven cases. J Neurosurg 1986;64: 843-848. 9. Jackson DL, Farrage J, Hynninen BC, et al. Suprascapular neuropathy in athletes: Case reports. Clin J Sports Med 1995; 5:134-137. 10. Kraft GH. Axillary, musculocutaneous and suprascapular nerve latency studies. Arch Phys Med Rehabil 1972;53:383-387. 11. Padua L, LoMonaco M, Padua R, et al. Suprascapular nerve entrapment: Neurophysiological localization in 6 cases. Acta Orthop Scand 1996;67:482-484.
ARTHROSCOPY FOR SUPRASCAPULAR NERVE PALSY 12. Post M, Mayer J. Suprascapular nerve entrapment. Diagnosis and treatment. Clin Orthop 1987;223:126-136. 13. Ganzhorn RW, Hocker JT, Horowitz M, et al. Suprascapular nerve entrapment: A case report. J Bone Joint Surg Am 1981; 63:492-494. 14. Chen AL, Ong BC, Rose DJ. Arthroscopic management of spinoglenoid cysts associated with SLAP lesions and suprascapular neuropathy. Arthroscopy 2003;19:E15-E21. 15. Chochole MH, Senker W, Meznik C, et al. Glenoid-labral cyst entrapping the suprascapular nerve: Dissolution after arthroscopic debridement of an extended SLAP lesion. Arthroscopy 1997;13:753-755. 16. 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;11:727-734. 17. Iannotti JP, Ramsey ML. Arthroscopic decompression of a ganglion cyst causing suprascapular nerve compression. Arthroscopy 1996;12:739-745. 18. Lichtenberg S, Magosch P, Habermeyer P. Compression of the suprascapular nerve by a ganglion cyst of the spinoglenoid notch: The arthroscopic solution. Knee Surg Sports Traumatol Arthrosc 2004;12:72-79. 19. Piatt BE, Hawkins RC, Fritz RJ, et al. Clinical evaluation and treatment of spinoglenoid notch ganglion cysts. J Shoulder Elbow Surg 2002;11:600-604. 20. Bigliani LU, Dalsey RM, McCann PD, et al. An anatomical study of the suprascapular nerve. Arthroscopy 1990;6:301-305. 21. Warner JP, Krushell RJ, Masquelet A, et al. Anatomy and relationships of the suprascapular nerve: Anatomical constraints to mobilization of the supraspinatus and infraspinatus muscles in the management of massive rotator-cuff tears. J Bone Joint Surg Am 1992;74:36-45. 22. Snyder SJ, Karzel RP, Del Pizzo W, et al. SLAP lesion of the shoulder. Arthroscopy 1990;6:274-279. 23. Burkart SS, Morgan CD. The peel-back mechanism: Its role in producing and extending posterior type II SLAP lesions and its effect on SLAP repair rehabilitation. Arthroscopy 1998;14: 637-640.
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24. Mestdagh H, Drizenko A, Ghestem P. Anatomical basis of suprascapular nerve syndrome. Anat Clin 1981;3:67-71. 25. Rengachary SS, Burr D, Lucas S, et al. Suprascapular entrapment neuropathy: A clinical, anatomical, and comparative study. Part 2: Anatomical study. Neurosurgery 1979;5:447451. 26. Aiello I, Serra G, Traina GC, et al. Entrapment of the suprascapular nerve at the spinoglenoid notch. Ann Neurol 1982; 12:314-316. 27. Kopell HP, Thompson WA. Pain and the frozen shoulder. Surg Gynecol Obstet 1959;109:92-96. 28. Ticker JB, Djurasovic M, Strauch RF, et al. The incidence of ganglion cysts and other variations in anatomy along the course of the suprascapular nerve. J Shoulder Elbow Surg 1998;7:472-478. 29. Cummins CA, Messer TM, Nuber GW. Suprascapular nerve entrapment. J Bone Joint Surg Am 2000;82:415-424. 30. Ferretti A, Cerullo G, Russo G. Suprascapular neuropathy in volleyball players. J Bone Joint Surg Am 1987;69:260263. 31. Ide J, Maeda S, Takagi K. Does the inferior transverse scapular ligament cause distal suprascapular nerve entrapment? An anatomic and morphologic study. J Shoulder Elbow Surg 2003; 12:253-255. 32. Demirhan M, Imhoff AB, Debski RE, et al. The spinoglenoid ligament and its relationship to the suprascapular nerve. J Shoulder Elbow Surg 1998;7:238-243. 33. Bektas H, Ay S, Yilmaz C, et al. Spinoglenoid septum: A new anatomic finding. J Shoulder Elbow Surg 2003;12:491-492. 34. Cummins CA, Anderson K, Bowen M, et al. Anatomy and histological characteristics of the spinoglenoid ligament. J Bone Joint Surg Am 1998;80:1622-1625. 35. Demirkan AF, Sargon MF, Erkula G, et al. The spinoglenoid ligament: An anatomic study. Clin Anat 2003;16:511-513. 36. Plancher KD, Peterson RK, Johnston JC, et al. The spinoglenoid ligament. Anatomy, morphology, and histologic findings. J Bone Joint Surg Am 2005;87:361-365. 37. Tung GA, Entzian D, Stern JB, et al. MR Imaging and MR arthrography of paraglenoid labral cysts. AJR Am J Roentgenol 2000;174:1707-1715.
Purpose: The purpose of this study was to investigate the results of arthroscopic treatment in 14 patients with suprascapular nerve palsy secondary to spinoglenoid ganglion cysts. Methods: Fourteen patients underwent arthroscopic decompression of ganglion cysts associated with suprascapular neuropathy. The most common presenting symptoms were pain and weakness, which lasted an average of 7.5 months. Ten of 14 patients were noted on examination to have atrophy, and all 14 patients had weakness of the infraspinatus. Magnetic resonance imaging (MRI) showed spinoglenoid ganglion cysts in all 14 patients; average cyst size was 3 cm. MRI revealed labral pathology in 12 of 14 cases; labral pathology was identified intraoperatively in all 14 patients. Results: Postoperatively, the average Simple Shoulder Test (SST) score was 11.5 (12 maximum), which was improved from an estimated preoperative score of 4.3. Improvement in external rotation strength was seen in 100% of patients who were examined postoperatively. No patients were taking pain medicine at latest follow-up. No complications were reported, and there were no clinical or symptomatic recurrences at an average follow-up of 51 months. Conclusions: Arthroscopic treatment of patients with spinoglenoid ganglion cysts is safe and effective, resulting in good clinical outcomes. In our study of 14 patients, no recurrences were seen at an average of 51 months of follow-up. Level of Evidence: Level IV, therapeutic case series. Key Words: Arthroscopic—Ganglion—Glenoid labrum—Suprascapular neuropathy.
G
anglion cysts of the shoulder are a relatively rare cause of shoulder pain. However, they often present with many of the same symptoms associated with more common conditions, making diagnosis difficult at times.1,2 To make an accurate diagnosis and implement an appropriate treatment plan, one must be aware of this uncommon cause of shoulder pain. Magnetic resonance imaging (MRI) and electromyography (EMG) are useful diagnostic tools in patients with suspected paralabral ganglion cysts and/or suprascap-
From Mount Carmel Health System (K.J.W.), Columbus, Ohio; and Southern California Orthopedic Institute, Medical Education (R.M.D., R.P.K., S.J.S.), Van Nuys, California, U.S.A. Address correspondence and reprint requests to Ryan M. Dopirak, M.D., Southern California Orthopedic Institute, Medical Education, 6815 Noble Avenue, Van Nuys, CA, U.S.A. E-mail: [email protected] © 2006 by the Arthroscopy Association of North America 0749-8063/06/2207-5239$32.00/0 doi:10.1016/j.arthro.2006.03.019
ular neuropathy. MRI accurately shows the size and location of ganglions—information that is critical for planning surgical intervention.3-5 It has also shown the frequent association of labral pathology with ganglion cysts.5-7 Although MRI can detect atrophy of the supraspinatus and infraspinatus,3,5 the diagnosis of suprascapular neuropathy can be confirmed only by EMG/ nerve conduction velocity (NCV) because the presence of a cyst does not necessarily mean that pathologic nerve compression is present.1,6,8-13 When ordering an EMG, one should specifically request evaluation of the suprascapular nerve because this may not be included as part of a routine upper extremity EMG. Many treatment options exist for patients with symptomatic paralabral ganglion cysts and suprascapular nerve compression. Initial treatment is typically nonoperative. For patients in whom a trial of conservative therapy is not effective, surgical intervention is considered. Traditionally, this disorder has been treated with open cyst excision. However, an open
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 22, No 7 (July), 2006: pp 721-727
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approach does not enable the surgeon to assess and treat labral pathology, which may predispose to recurrence of the cyst. In recent years, numerous authors have developed arthroscopic techniques designed to decompress spinoglenoid cysts and concomitantly address labral pathology, which is present in a large percentage of these patients.2,6,7,14-19 The purpose of this study was to report the results of arthroscopic treatment of 14 patients with suprascapular nerve palsy secondary to spinoglenoid ganglion cysts. Our hypothesis was that arthroscopic treatment of spinoglenoid ganglion cysts that cause suprascapular neuropathy and concomitant labral pathology results in good outcomes and low rates of clinical recurrence. METHODS Between 1996 and 2001, 14 patients underwent arthroscopic decompression of ganglion cysts associated with suprascapular nerve palsy. Two surgeons were involved in this study, both of whom had extensive experience in shoulder arthroscopy. All patients were treated at the same institution. A retrospective chart review was performed for all patients. Data collected included presenting symptoms, physical examination findings, MRI evaluation, EMG results, intraoperative findings, and details of arthroscopic treatment. Twelve of the 14 patients returned for follow-up and were evaluated by history and physical examination. The remaining 2 patients were evaluated by mail survey or telephone interview. Outcomes were measured with the Constant-Murley Score, the Simple Shoulder Test (SST), and the Hawkins Shoulder Evaluation Form. Average patient age was 41 years (range, 27 to 63 years). Ten of 14 patients participated in recreational athletics. No high-level athletes were included in this study. In 6 of 14 patients, shoulder pathology was considered work related. In 12 of 14 patients, the dominant extremity was involved. All 14 patients presented with reports of shoulder pain. In 7 patients, the pain was radiating. Five patients described night pain. In 8 patients, pain was exacerbated by reaching or raising the arm. Two patients reported exacerbation of pain with simple use or motion of the arm. In 10 of 14 patients, atrophy was noted on examination. Preoperatively, all 14 patients had weakness of the infraspinatus muscle. External rotation strength was 4/5 in 11 patients, 3/5 in 2 patients, and 1/5 in 1 patient. Muscle strength was tested manually. The exact type and duration of nonoperative treatment varied in our study population because many
patients had received treatment before they were referred to our institution. Nonoperative treatment typically consisted of rest, ice, nonsteroidal anti-inflammatory drugs (NSAIDs), physical therapy (PT), and/or cortisone injections. Average time from onset of symptoms to surgery was 7.5 months. One patient underwent previous open cyst excision. All 14 patients had a preoperative MRI. Spinoglenoid ganglion cysts were seen in all 14 patients; average cyst size was 3 cm. Infraspinatus signal change was noted in 8 of 14 cases. Labral pathology was present in 12 of 14 cases. Eleven patients had EMGs preoperatively; all were positive for denervation of the infraspinatus. Because of the retrospective nature of this study, EMGs were not obtained in all 14 patients. Assessment of statistical correlation between degree of denervation and postoperative outcome was not feasible due to our small sample size. This was not feasible because of our small sample size. Arthroscopic Technique A complete 15-point diagnostic examination of the glenohumeral joint is performed, with particular attention paid to the superior labrum. If a SLAP lesion (Fig 1) or posterior labral detachment is found, the cyst may sometimes be decompressed through this lesion. If the labrum is well attached, an electrosurgical device or shaver is used to create a 1-cm capsulotomy at the posterior superior glenoid rim. The exact location of the capsulotomy is based on the anatomic location of
FIGURE 1. Arthroscopic picture of large type II SLAP lesion with extension of tear into posterior superior labrum. A thorough and complete diagnostic arthroscopy is mandatory in all patients with symptomatic spinoglenoid ganglion cysts because concomitant labral disease is very common. The patient is in the lateral decubitus position with an arthroscope in the posterior portal (left shoulder).
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FIGURE 2. (A) Axial, (B) coronal oblique, and (C) sagittal oblique T2-weighted MRIs of a spinoglenoid ganglion cyst.
the ganglion, which is determined from the preoperative MRI scan (Fig 2). With the arthroscope in the posterior portal, a blunt dissecting tool is used to develop and probe the capsulotomy until the cyst is located. A characteristic amber-colored fluid will be encountered when the cyst is entered. This fluid should be seen in most patients with large paralabral cysts if the capsulotomy has been placed in the correct anatomic location. After the cyst has been identified, an arthroscopic shaver is placed within the cyst, the fluid is evacuated with suction, and the cyst wall is removed (Fig 3). The shaver is kept pointed at the glenoid neck at all times. So that damage to the suprascapular nerve can be avoided, no attempt is made to remove the capsule from the area about the spine of the scapula. Dissection should not extend beyond 1 cm medial to the posterior superior labral attachment to the glenoid; in
this way, the nerve is avoided as it courses through the spinoglenoid notch. Dissection should not extend beyond 1 cm medial to the posterior superior labral attachment to the glenoid, as anatomic studies have shown that the distance from the posterior glenoid rim to the suprascapular nerve or its branches is approximately 1.8 to 2.1 cm.20,21 The arthroscope is next moved to the anterior portal, and the shaver is introduced through the posterior portal. With the shaver again directed at the glenoid neck, the capsulotomy is further developed to remove the posterior portion of the cyst. It should again be stressed that dissection should be carried no farther than 1 cm medial to the glenoid so that iatrogenic injury to the suprascapular nerve can be avoided. It is possible that a small residual portion of the cyst wall may present more medially toward the scapular spine. However, this is clini-
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K. J. WESTERHEIDE ET AL. underwent subacromial decompression; 1 of these 2 patients also had a distal clavicle excision. RESULTS
FIGURE 3. Characteristic appearance of amber-colored, gelatinous material within a paraglenoid ganglion cyst.
cally insignificant because the offending lesion has been adequately decompressed. After the cyst has been removed, remaining intraarticular pathology is addressed. This includes debridement of type I SLAP lesions, as well as repair of type II SLAP lesions with the single anchor– double suture (SADS) technique22 (Fig 4). Occasionally, the posterior superior labrum “peel back” phenomenon as described by Burkart and Morgan23 is present and may require stabilization with a single loaded anchor placed posteriorly. Postoperative rehabilitation varies according to the treatment rendered. If labral debridement is performed without formal SLAP repair, patients will use a sling for comfort for a limited time. Full return to activities is often possible within 6 weeks. If posterior labral repair or SLAP repair is performed, the patient is supported in an UltraSling (DJ Orthopedics, Carlsbad, CA) for approximately 3 weeks. Elbow, wrist, and hand exercises, along with gentle pendulum exercises, are begun during the first week. Active range-of-motion exercises are started at 3 weeks. Biceps strengthening is delayed until 6 weeks postoperatively. Full activities are resumed when motion and strength are normal, usually about 4 months postoperatively. All 14 patients in this study underwent shoulder arthroscopy with spinoglenoid cyst decompression. Labral pathology was identified in all 14 patients. Labral repair was performed in patients with type II SLAP lesions, posterior superior labral tears, and/or posterior Bankart lesions (7 patients). Debridement alone was performed in patients with type I SLAP tears and/or degenerative fraying of the posterior labrum (7 patients). Two patients
Average patient follow-up in this study was 51 months (range, 24 to 73 months). Postoperatively, external rotation strength was 5/5 in 10 patients and 4/5 in 2 patients. Postoperative external rotation strength was improved in all 12 patients, as compared with preoperative external rotation strength. The average Constant-Murley score was 94 (100 maximum) postoperatively. The average SST score was 11.5 (12 maximum), which was improved from an estimated preoperative SST score of 4.3. As compared with preoperative activity level, 8 patients rated their activity as unchanged postoperatively; 4 patients rated their activity as improved, and 2 patients rated their activity as slightly diminished. No patients were currently taking pain medicine at latest follow-up. The average overall satisfaction score was 1.5 (range, 1 to 13), where 1 indicated that the patient was fully satisfied and 13 meant that outcomes were unsatisfactory. No complications were reported, and there were no clinical or symptomatic recurrences. DISCUSSION The suprascapular nerve travels below the superior transverse scapular ligament as it passes through the suprascapular notch. The space available for the su-
FIGURE 4. Repair of type II SLAP lesion in the left shoulder. Adequate treatment of concomitant labral disease is necessary to prevent recurrent ganglion cyst formation. The patient is in the lateral decubitus position with an arthroscope in the posterior portal (same patient as in Fig 1).
ARTHROSCOPY FOR SUPRASCAPULAR NERVE PALSY prascapular nerve at this location depends on the shape of the suprascapular notch and the size and structure of the transverse scapular ligament.24,25 After providing innervation to the supraspinatus, the nerve continues around the scapular spine through the spinoglenoid notch. At this location, it is relatively constrained by the inferior transverse scapular ligament, or the spinoglenoid ligament. After passing through the spinoglenoid notch, the nerve terminates by giving 2 to 4 motor branches to the infraspinatus13,21,24 (Fig 5). The suprascapular nerve is susceptible to injury at both the suprascapular notch and the spinoglenoid notch.26,27 Proximal insult leads to weakness of both the supraspinatus and the infraspinatus, whereas distal insult leads to isolated infraspinatus weakness. Suprascapular neuropathy may result from injuries involving excessive traction or compression. Traction injuries most commonly occur at the suprascapular notch because of the variable shape of the notch and the tethering effect of the transverse scapular ligament.2,28 However, traction injuries may also occur at the spinoglenoid notch, especially in patients involved in repetitive overhead athletic activities.2,29,30 The focus of this study is suprascapular neuropathy secondary to direct compression by a ganglion cyst. Extrinsic compression by a ganglion cyst occurs most
FIGURE 5. Anatomy of the suprascapular nerve. (Reprinted with permission from Orthop Clin North Am 2003;34:522.)
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commonly at the spinoglenoid notch.2 It is postulated that a thickened spinoglenoid ligament may amplify the deleterious effects of a ganglion on the suprascapular nerve31 in that it may further diminish the space available for the nerve. However, this is not known with certainty because the prevalence and the morphology of the spinoglenoid ligament have been reported with wide variability.24,26,31-36 Initial treatment for patients with symptomatic ganglion cysts of the shoulder should be nonoperative. Patients should be advised to avoid repetitive overhead activities, as well as other actions that aggravate the condition. A physical therapy program should be prescribed that improves flexibility and strengthens the scapular stabilizers, as well as the rotator cuff muscles. It is possible for cysts to spontaneously resolve. Piatt et al.19 documented this on MRI in 2 patients, both of whom experienced subsequent improvement of their symptoms. However, these patients should be monitored closely for signs of clinical deterioration because it is possible for the cysts to become larger. For patients who fail to respond to conservative measures, a variety of treatment options exist. Imageguided aspiration performed with ultrasound, computed tomography (CT), or MRI has been reported with mixed results. Piatt et al.19 performed needle aspiration of spinoglenoid cysts in 11 patients. At final evaluation, 5 patients were found to have recurrent cyst formation documented on MRI. Tung et al.37 reported that 3 of 4 patients who underwent cyst aspiration showed recurrence at 4 months. The primary disadvantage of aspiration as the sole treatment modality is its inability to assess and treat patients with intra-articular pathology, which may predispose to recurrence of the ganglion cyst. Surgical options for the treatment of patients with ganglion cysts of the shoulder include both open and arthroscopic techniques. Traditionally, the open posterior approach for decompression of spinoglenoid cysts has been used with success. The advantage of an open decompression is direct visualization of the cyst and suprascapular nerve. However, one disadvantage is the potential morbidity associated with the surgical approach, which entails deltoid detachment or splitting. Additionally, an open approach does not enable the surgeon to assess and treat labral pathology, which may ultimately predispose to recurrence of the cyst. The combination of arthroscopy to address labral pathology and aspiration or open cyst excision is also an option. However, arthroscopic treatment alone has shown good success in limited case series and avoids
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the potential morbidity of open decompression.2,6,14,15,17,18 Appropriate treatment of labral pathology combined with decompression of the spinoglenoid ganglion cyst typically provides good clinical outcomes and low rates of recurrence.6,14,16-19 Iannotti17 presented 3 patients treated all-arthroscopically with a posterior superior capsulotomy. At 1 year, no recurrences were seen on MRI, and all patients had complete relief of pain and return of external rotation strength. Chen et al.14 reported 3 patients with suprascapular neuropathy secondary to cyst compression at the spinoglenoid notch. All 3 patients were treated with arthroscopic cyst decompression and SLAP repair. Postoperative EMG and MRI showed return of nerve function and cyst resolution. Fehrman et al.16 studied 6 patients with suprascapular nerve compression secondary to a ganglion cyst. All 6 also had arthroscopically confirmed posterior capsulolabral injuries. Treatment consisted of a combination of arthroscopic and open methods. Postoperatively, 5 of 6 patients reported complete resolution of pain. The single remaining patient reported improvement in pain but not complete resolution. Lichtenberg et al.18 evaluated 8 patients with suprascapular neuropathy secondary to spinoglenoid notch ganglion cysts. All patients were examined arthroscopically; 6 were found to have SLAP lesions. Arthroscopic cyst decompression was performed in all patients. Formal repair was performed in the 6 patients with SLAP lesions. In the 2 patients without identifiable labral pathology, a capsulotomy was performed and left open. All patients improved in terms of pain, strength, and function. Piatt et al.19 evaluated 73 patients with symptomatic spinoglenoid notch ganglion cysts. Multiple treatment modalities were employed, including nonoperative treatment and needle aspiration, as well as various combinations of arthroscopic and open surgical approaches to treatment of labral pathology and ganglion cysts. In 10 patients, cyst decompression and treatment of labral pathology were performed all-arthroscopically. Postoperatively, all 10 patients were satisfied, and none reported any pain at rest or with activities of daily living. In our study of 14 patients treated all-arthroscopically, the average postoperative SST score was 11.5 (12 maximum). The average satisfaction score was 1.5 (1, complete satisfaction; 13, unsatisfactory). Of patients who were examined postoperatively, 100% showed improvement in external rotation strength. No clinical or symptomatic recurrences occurred.
This study is limited by the fact that it is a retrospective case series with no control group. Postoperative outcomes were quantified, but preoperative shoulder scores were not calculated or were simply estimated. This makes accurate quantification of patient improvement difficult. Additionally, the disease encountered within our patient population was variable. As a result, treatment was not identical for each patient. Although no clinical or symptomatic recurrences occurred, postoperative MRIs were not obtained to confirm cyst resolution. This would have provided a more definitive method of evaluating recurrences, but it was financially impractical. Our technique involves treatment of labral pathology and direct removal of the cyst. It is not known with certainty whether simply addressing the labral pathology alone would lead to cyst resolution. This would offer the potential benefit of minimizing the risk of iatrogenic injury to the suprascapular nerve. Further study is warranted. In conclusion, arthroscopic treatment of patients with spinoglenoid ganglion cysts is safe and effective, resulting in good clinical outcomes. In our study of 14 patients, no recurrences were reported at an average of 51 months’ follow-up.
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