Scapulothoracic Arthroscopy

 

 

 

DEFINITION

Scapulothoracic bursitis and snapping scapula syndrome are rare conditions characterized by periscapular pain with or without mechanical crepitus.

Scapulothoracic crepitus was first described by Boinet6 in 1867.

The resultant crepitant sounds were originally described as froissement, frottement, and craquement in 1904 by Mauclaire.21

Milch24 differentiated the sounds produced by soft tissues (frottement) and those produced by osseous or fibroosseous lesions (craquement).

 

 

ANATOMY

 

Bony anatomy

 

 

The scapula spans superoinferiorly from the second to the seventh rib and is connected to the axial skeleton via the acromioclavicular and sternoclavicular joints.

 

The scapula is composed of borders (medial, lateral, and superior) and four angles (inferomedial, medial, lateral, and superomedial) which serve as important arthroscopic landmarks.

 

The scapula is concave on its anterior surface as it articulates with the convex thoracic cage.

 

 

The osseous anatomy of the scapulothoracic articulation can vary considerably,1 although some of these nonpathologic variations may be related to snapping scapula39:

 

 

Increased concavity of the medial scapular border39 Superomedial hooking12

 

 

Luschka tubercle (bony prominence at superomedial angle)24,39 Teres major tubercle39

 

Thickened superomedial and inferomedial angle1

 

The suprascapular notch occurs just medial to the take-off of the coracoid process and its shape has been categorized into six types (I-VI) by Rengachary34:

 

Type I (8%)—no notch is present.

 

Type II (31%)—notch is V-shaped and medially placed.

 

Type III (48%)—notch is U-shaped and has been found to be associated with suprascapular nerve

entrapment.2

 

Type IV (3%)—notch is very small and V-shaped. The suprascapular nerve travels in a groove adjacent to the notch.

 

Type V (6%)—notch is U-shaped with ossification of the transverse humeral ligament.

 

Type VI (4%)—complete ossification of transverse humeral ligament leaving a foramen through which the suprascapular nerve travels.

 

The transverse scapular ligament, which spans the suprascapular notch, can also vary in morphology. There are three types as described by Polguj et al33:

 

Fan-shaped (55%)

 

 

Band-shaped (42%)—more likely to result in nerve entrapment Bifid (3%)

 

Muscular anatomy

 

 

Trapezius muscle

 

 

Originates from the cervical and thoracic spinous processes and inserts along the superior aspect of the scapular spine

 

 

Innervated by the spinal accessory nerve along its deep surface Serratus anterior muscle

 

 

Originates from the ribs and inserts on the anterior aspect of the medial scapular border Innervated by the long thoracic nerve along its anterior surface

 

Subscapularis muscle

 

 

Originates within the subscapular fossa on the anterior surface of the scapula and inserts into the lesser tuberosity of the proximal humerus

 

 

Innervated by the upper and lower subscapular nerves along its anterior surface Levator scapulae muscle

 

Originates from the spinous processes of the cervical spine and inserts along the medial border of the scapula

 

 

Innervated by the dorsal scapular nerve Rhomboid major muscle

 

 

Originates from the upper thoracic vertebrae and inserts along the medial border of the scapula Innervated by the dorsal scapular nerve

 

Rhomboid minor muscle

 

 

Originates from the lower cervical and upper thoracic spinous processes and inserts along the medial border of the scapula at the base of the scapular spine

 

Innervated by the dorsal scapular nerve

 

Neurovascular anatomy (FIG 1)

 

 

A thorough understanding of surrounding neurovascular structures is necessary to prevent iatrogenic injury.

 

The dorsal scapular nerve and artery run superoinferiorly 1 to 2 cm medial to the medial scapular border and deep to the rhomboid musculature (Ruland). Portal placement less than 3 cm from the medial scapular border endangers these structures.

 

The spinal accessory nerve is located in the central portion of the levator scapulae muscle deep to the trapezius muscle.36 Portal placement superior to the level of scapular spine endangers this structure.

 

P.135

 

 

 

 

FIG 1 • Illustration of neurovascular anatomy and safe portal position around the scapulothoracic articulation.

 

 

The long thoracic nerve travels along the anterior belly of the serratus anterior muscle. This nerve is infrequently in danger unless portals are placed in an extraordinarily lateral position.

 

The suprascapular nerve branches from the brachial plexus and runs posterosuperiorly with the suprascapular artery. The nerve passes through the suprascapular notch below the transverse scapular ligament, whereas the artery passes above this ligament. These structures are endangered with superomedial portal placement or when superomedial scapular resection is performed. It is important to

place arthroscopic portals 2 to 3 cm lateral to the suprascapular notch to avoid iatrogenic injury.1,4

 

Bursal anatomy (FIG 2)

 

 

Anatomic bursae

 

 

Nonpathologic bursae that occur normally to allow gliding of surfaces in and around the scapulothoracic articulation

 

The infraserratus bursa lies between the anterior surface of the serratus anterior muscle and the posterior chest wall to allow gliding between these two structures (Kuhne).

 

The supraserratus bursa lies between the anterior surface of the subscapularis muscle and the posterior surface of the serratus anterior muscle to allow gliding between these two structures.18

 

Adventitial bursae

 

 

Pathologic bursae that most often occur at the superomedial and inferomedial scapular angles10,32

 

Symptoms occurring at the inferomedial angle are most likely caused by the presence of pathologic bursal tissue between the serratus anterior and the posterior chest wall.24,37

 

Symptoms occurring at the superomedial angle are thought to result from the presence of pathologic supraserratus or infraserratus bursae.11,17

 

Symptoms occurring at the medial base of the scapular spine are most often caused by a pathologic scapulotrapezial bursa located deep to the trapezius muscle near the junction of the medial border and the scapular spine.

 

 

Biomechanics

 

 

Smooth scapulothoracic stability and motion occurs as a result of the coordinated contraction of periscapular musculature and the function of various bursae that lie within muscular planes to allow gliding between surfaces. The scapulothoracic articulation effectively positions the glenoid to maximize range of motion capacity at the glenohumeral joint.

 

PATHOGENESIS

 

 

Scapulothoracic disorders result from abnormal stresses in the presence of predisposing anatomic variation. Bursitis

 

Most commonly arise as an overuse syndrome of the shoulder

 

 

P.136

 

 

 

FIG 2 • A. Illustrates the relative locations of anatomic and adventitial bursae around the scapula. B. Represents an axial slice showing the various locations of scapulothoracic bursae and their relationship to periscapular musculature and the scapular body.

 

 

Bursal tissue becomes irritated when gliding over uneven surfaces.

 

Most commonly occurs at the superomedial, medial, and inferior angles of the scapula

 

Fibrosis can occur if chronic inflammation is present. Fibrotic bursal tissue can produce recurrent bursitis and snapping scapula in the absence of a distinct scapulothoracic mass.17,32

 

Snapping scapula

 

 

Most commonly results from soft tissue entrapment between the scapula and underlying thorax. Very uncommonly, snapping scapula can also be due to an osseous or soft tissue mass with or without concurrent bursitis. Crepitus can also occur in asymptomatic individuals; thus, it should not be considered pathologic unless accompanied by pain and/or shoulder dysfunction.

 

Masses are rare in clinical practice. However, the most frequent scapulothoracic masses that result in crepitation include osteochondromas at the superomedial angle,13,40 elastofibroma dorsi8 at the inferomedial angle, and chondrosarcoma (especially in older patients). Resection of these masses is

curative in the majority of cases.13,40

 

Other mechanical causes of “snapping” include bursal fibrosis,23,24 malunion of scapular or rib fractures,38 variations in anatomy of the scapula or posterior chest wall,1,12,39 scoliosis/kyphosis,20 first rib resection,41 and, rarely, anomalous musculature.

 

NATURAL HISTORY

 

Repeated scapulothoracic motion can lead to inflammation, scarring, and chronic bursitis in anatomically predisposed individuals.

 

The presence of osseous or soft tissue masses exacerbates the inflammatory cycle leading to pain and altered scapulohumeral kinematics.

PATIENT HISTORY AND PHYSICAL FINDINGS

 

History

 

 

Patients may report a history of repetitive overhead activity or an inciting traumatic event.22

 

Patients may present with a wide range of symptoms ranging from mild, intermittent pain to disabling pain and dysfunction. Pain may increase with overhead activities in some patients.

 

Audible or palpable crepitus may occur with or without the presence of bursitis.3,22 Approximately, one-third of patients report bilateral involvement.

 

 

A possible genetic predisposition for scapulothoracic crepitus has been reported.10 Physical examination

 

Inspection of cervical and thoracic spine for evidence of scoliosis and kyphosis which may result in

scapulothoracic incongruency.10 Referred pain syndromes may also occur as a result of cervical radiculopathy or discopathy.

 

Palpation of scapular margins may reveal site of bursal irritation and palpable crepitus.

 

 

Inflammation at the superomedial angle is most common; however, inflammation at the inferomedial angle can also occur on occasion.

 

Range of motion should always be tested.

 

 

Active and passive range-of-motion testing is required to evaluate the shoulder for painful crepitus and scapulohumeral kinematics.

 

 

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Scapulothoracic masses or motor compensation can result in pathologic scapular winging. Exacerbation of crepitus can result from scapulothoracic compression during arm abduction.23

 

Periscapular muscle strength should always be tested.

 

 

Trapezius muscle

 

 

Compare active shoulder “shrug” to contralateral shoulder.

 

Rhomboid musculature and levator scapulae

 

 

Compare active scapular retraction to contralateral shoulder.

 

Serratus anterior muscle

 

 

Wall push-up may demonstrate medial scapular winging in patients with serratus anterior weakness.

 

IMAGING AND OTHER DIAGNOSTIC STUDIES

 

Radiographs (FIG 3)

 

 

Anteroposterior (AP), lateral, and axillary films in the scapular plane should be obtained to screen for bony abnormalities.

 

Computed tomography (CT) scanning

 

When a lesion is identified by x-ray, CT scanning (threedimensional, if possible) is indicated.

 

Three-dimensional CT scanning has the highest sensitivity for the detection of osseous lesions that may contribute to snapping scapula or scapulothoracic bursitis.27

 

Magnetic resonance imaging (MRI) scanning (FIG 4)

 

 

MRI scanning is best used to detect soft tissue masses, bursal inflammation, and sometimes abnormal scapular angulation and is therefore indicated when these etiologies are suspected.

 

 

 

FIG 3 • Radiograph demonstrating anterior angulation of the superomedial angle (yellow arrow).

 

 

 

FIG 4 • MRI demonstrating anterior angulation of the superomedial angle (yellow arrow).

 

DIFFERENTIAL DIAGNOSIS

 

 

Scapulothoracic bursitis Mass

 

 

 

Elastofibroma dorsi Osteochondroma Chondrosarcoma

 

Scoliosis/kyphosis

 

 

Referred pain (eg, cervical radiculopathy, gallbladder disease) Glenohumeral disease

 

Malunited scapular or rib fracture

 

Complication of first rib resection

 

NONOPERATIVE MANAGEMENT

 

A trial of conservative management is generally indicated when the inciting lesion is benign. However, it must be recognized that nonoperative management is most effective in situations in which there is no mass

present.23

 

 

Rest and nonsteroidal anti-inflammatory medications are usually helpful.16 Steroid injections can be both diagnostic and therapeutic in many cases.

 

Physical therapy should emphasize periscapular muscle strengthening (especially the serratus anterior and subscapularis muscles15,30) along with postural training.

 

The use of ultrasound has been debated; however, it is unlikely to exacerbate symptoms and may be used at the discretion of the clinician.

 

Patients with kyphosis often benefit from a figure-of-eight harness to reduce scapulothoracic incongruity.

 

SURGICAL MANAGEMENT

 

Indicated for patients who have failed conservative therapy. Bursectomy is most reliable in improving symptoms when local injection results in symptomatic improvement.17,20,28

 

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Superomedial scapular resection is indicated when the angle is found to be prominent via arthroscopic visualization or preoperative radiographs.

 

Open treatment has been used to successfully treat both bursitis28,37 and painful crepitus.23,35

 

 

Requires a large exposure and subperiosteal dissection of medial musculature with subsequent repair back to bone after dèbridement of pathologic tissue is accomplished.

 

Can be used for the resection of large, sessile masses

 

Arthroscopic management minimizes morbidity of the exposure, eliminates need for muscle detachment, improves visualization, and facilitates early rehabilitation.

 

 

Can be used for the resection of pedunculated masses

 

Preoperative Planning

 

Preoperatively, the points of symptomatology along with bony landmarks are marked with a pen so they can be identified easily during surgery.

 

Positioning

 

The patient is positioned prone and the extremity is draped free to allow for intraoperative scapular positioning. The posterior thorax is prepared widely and the affected extremity is placed in a stockinette.

 

The dorsum of the hand is placed over the small of the back (the so-called “chicken wing” position) (FIG 5). This position of maximal internal rotation and extension increases the space available for operation between

the anterior scapula and the posterior chest wall.26,29 Additional space can be obtained by applying a medially directed force on the upper arm during surgery.

Approach

 

The infraserratus bursa is first insufflated with a 100 mL solution of saline containing local anesthetic and epinephrine to improve hemostasis.

 

To avoid the dorsal scapular nerve and artery, portals are placed approximately 3 cm medial to the medial border of the scapula inferior to the level of the scapular spine (FIGS 6 and 7). Medial placement also allows

for a more parallel trajectory toward the inflamed bursa, avoiding penetration of the chest wall.36

 

 

 

FIG 5 • The arm is internally rotated and placed behind the back to increase the space available for arthroscopic visualization. This is also known as the chicken wing position.

 

 

 

FIG 6 • Placement of the first arthroscopic portal.

 

 

An initial viewing portal is established approximately 3 cm medial to the inferomedial angle of the scapula (FIG 8). A 4.0-mm 30-degree arthroscope is inserted and diagnostic arthroscopy is performed. Under direct visualization, a second working portal is placed by triangulation approximately 3 cm medial to the medial border of the scapula just inferior to the level of the scapular spine (FIG 9).

 

A superior accessory portal of Bell, located approximately at the junction between the medial one-third and lateral two-thirds of the superior margin of the scapula, can also be placed to aid in superomedial angle

resection.4,7 However, any portal placed superior to the level of the scapular spine places the spinal accessory nerve, the dorsal scapular nerve and artery, and the transverse cervical artery at risk for iatrogenic injury.

 

The use of a 70-degree arthroscope may be necessary to improve visualization in some cases.

 

From within the infraserratus bursa at the superomedial angle, the intercostal muscles are located inferiorly, the rhomboid musculature and the levator scapulae are located medially, and the subscapularis is located laterally.

 

 

 

FIG 7 • Arthroscopic view from the first portal.

 

 

P.139

 

 

 

FIG 8 • The second “working” arthroscopic portal.

 

 

 

FIG 9 • And the optional superior portal.

 

TECHNIQUES

• Resection of Bursal Tissue

The infraserratus bursa is resected taking care to avoid resection of muscle fibers in the area.

 

TECH FIG 1 • A,B. Resection and débridement of the scapula.

 

The superomedial border of the scapula is skeletonized using a radiofrequency ablator to ensure complete resection of the symptomatic supraserratus or infraserratus bursa (TECH FIG 1A,B).

 

 

• Superomedial Angle Resection

   

  When scapular snapping was clinically evident after skeletonization of the superomedial angle, a spinal needle is inserted with fluoroscopic guidance to help localize the most lateral extent of the superomedial

  scapular angle and aid in resection (TECH FIG 2A,B).26

   

   

   

  TECH FIG 2 • A,B. The spinal needle is used as a guide to the medial border of the scapula. (continued)

   

   

  A high-speed bur is introduced to remove a 2 (superior to inferior) × 3 cm (medial to lateral) section of bone from the superomedial angle, effectively eliminating the medial border convexity that was once

  present.25

   

  The resection is viewed from each portal to ensure the presence of a smooth surface and adequate clearance (TECH FIG 2C,D).

   

  P.140

   

   

   

  TECH FIG 2 • (continued) C,D. Final débridement.

• Dynamic Scapular Examination

 

While the patient is still under anesthesia, a dynamic examination of the scapula is necessary to ensure the resolution of crepitation and to further ensure adequate clearance between the scapular body and the posterior chest wall.

Closure

 

The portals are closed routinely, and the shoulder is placed in a sling for postoperative comfort.

 

 

PEARLS AND PITFALLS

Portal

placement

• The surgeon should consider the neurovascular and thoracic structures.

• The surgeon should enter parallel to the ribs and use a spinal needle to accurately localize the superomedial angle.

• More inferiorly placed portals are safer because the dorsal scapular nerve arborizes superiorly and terminally.

Visualization

• Predistention with a solution containing normal saline and epinephrine for

  visualization and hemostasis.

• Pump pressure should be optimized.

• Avoid inadvertent thoracotomy.

Bursectomy

• Perform a complete bursectomy.

• Avoid perforating the subscapularis muscle medially, as this can result in overt bleeding.

Partial ▪ Preoperative planning with normal or three-dimensional CT scans

scapulectomy ▪ Localize the superomedial angle with a spinal needle.

• Perform adequate resection. We prefer to remove a triangular section of bone at the superomedial angle including the most superior 2 cm of the medial border and the most medial 3 cm of the superior border.

 

 

POSTOPERATIVE CARE

 

Open techniques, which require detachment of medial musculature, typically require sling immobilization for 4 weeks followed by passive range-of-motion exercises. Eight weeks postoperatively, active motion is begun; however, this is dictated by the specific muscular repairs that were required for adequate exposure during the

surgical procedure. Periscapular strengthening is begun approximately 12 weeks postoperatively.14

 

An immobilization sling is also used after arthroscopic procedures; however, the sling is discontinued after approximately 48 hours. Immediately postoperatively, passive range of motion is begun with progression to active motion is based on patient tolerance and the discretion of an experienced physical therapist.

Approximately 4 weeks postoperatively, glenohumeral strengthening is begun. This is followed by periscapular strengthening which is begun at approximately 8 weeks postoperatively.25

 

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OUTCOMES

Open bursectomy and scapuloplasty

 

McCluskey and Bigliani22 reported good to excellent outcomes in eight of nine patients. The patient who had a poor outcome had an iatrogenic spinal accessory nerve injury.

Nicholson and Duckworth28 reported significant improvements in the American Shoulder and Elbow Surgeons’ (ASES) scores and Visual Analog Scale (VAS) scores for pain.

 

 

Arntz and Matsen3 reported complete pain relief in 12 of 14 shoulders treated with partial scapulectomy after a 42-month follow-up period.

Arthroscopic bursectomy and mini-open scapuloplasty

 

Lien et al19 reported the outcomes using this technique in 12 patients with a mean follow-up of approximately 3 years. ASES scores improved by 52 points and VAS pain scores improved by 6 points over preoperative levels.

Arthroscopic bursectomy and scapuloplasty

Many authors have described similar outcomes after arthroscopic techniques compared to open or mini-open procedures.9,13,19,31

Millett et al25 reported significant improvements in pain and function at a minimum 2-year follow-up in 23 shoulders with scapulothoracic bursitis who underwent bursectomy with or without scapulectomy. Those who underwent both bursectomy and scapulectomy had better outcomes scores compared to those who underwent bursectomy in isolation.

In a study by Pearse et al,31 9 of 13 patients showed significant improvements in pain and function with or without partial scapulectomy. Their median Constant score was 87 (range, 58 to 95). The 4 remaining patients who felt they did not improve over their preoperative baseline had a Constant score of 55 (range, 32 to 66). Six of 9 patients who participated in sports returned to their premorbid level of competition.

Blønd and Rechter5 reported on 20 patients who underwent scapulothoracic bursectomy and superomedial angle resection after a mean 2.9-year follow-up period. Eighteen of the 20 patients reported improvement. The median Western Ontario Rotator Cuff (WORC) index improved from 35.0 preoperatively to 86.4 postoperatively in these patients.

 

COMPLICATIONS

Dorsal scapular nerve and/or artery injury due to medial placement of arthroscopic portals

Spinal accessory nerve injury due to placement of arthroscopic portals superior to the confluence of the scapular spine

Long thoracic nerve injury due to extensive lateral dissection Incomplete bursectomy resulting in continued symptoms Inadequate scapulectomy resulting in continued symptoms Incorrect diagnosis

 

 

REFERENCES

1. Aggarwal A, Wahee P, Harjeet, et al. Variable osseous anatomy of costal surface of scapula and its implications in relation to snapping scapula syndrome. Surg Radiol Anat 2011;33(2):135-140.

    

    

2. Albino P, Carbone S, Candela V, et al. Morphometry of the suprascapular notch: correlation with scapular dimensions and clinical relevance. BMC Musculoskelet Disord 2013;14:172.

    

    

3. Arntz C, Matsen FI. Partial scapulectomy for disabling scapulothoracic snapping. Orthop Trans 1990;14:252-253.

    

    

4. Bell SN, van Riet RP. Safe zone for arthroscopic resection of the superomedial scapular border in the treatment of snapping scapula syndrome. J Shoulder Elbow Surg 2008;17(4):647-649.

    

    

5. Blønd L, Rechter S. Arthroscopic treatment for snapping scapula: a prospective case series. Eur J Orthop Surg Traumatol 2014;24(2): 159-164.

    

    

6. Boinet W. Snapping scapula. Societe Imperiale de Chirurugie 1867; 8(2):458.

    

    

7. Chan BK, Chakrabarti AJ, Bell SN. An alternative portal for scapulothoracic arthroscopy. J Shoulder Elbow Surg 2002;11:235-238.

    

    

8. Cinar BM, Akpinar S, Derincek A, et al. Elastofibroma dorsi: an unusual cause of shoulder pain [in Turkish]. Acta Orthop Traumatol Turc 2009;43(5):431-435.

    

    

9. Ciullo JV. Subscapular bursitis: treatment of “snapping scapula” or “wash-board syndrome.” Arthroscopy 1992;8:412-413.

    

    

10. Cobey MC. The rolling scapula. Clin Orthop Relat Res 1968;60:193-194.

     

     

11. Codman E. The Shoulder. Malabar, FL: Krieger Publishing, 1984:1-31.

     

     

12. Edelson JG. Variations in the anatomy of the scapula with reference to the snapping scapulas. Clin Orthop Relat Res 1996;(322):111-115.

     

     

13. Fukunaga S, Futani H, Yoshiya S. Endoscopically assisted resection of a scapular osteochondroma causing snapping scapula syndrome. World J Surg Oncol 2007;5:37.

     

     

14. Gaskill TR, Millett PJ. Snapping scapula syndrome: diagnosis and management. J Am Acad Orthop Surg 2013;21:214-224.

     

     

15. Groh GI, Simoni M, Allen T, et al. Treatment of snapping scapula with a periscapular muscle strengthening program. J Shoulder Elbow Surg 1996;5(2):S6.

     

     

16. Kibler WB. Snapping scapula. Arthroscopy 2010;26(3):299-300.

     

     

17. Kuhn JE, Plancher KD, Hawkins RJ. Symptomatic scapulothoracic crepitus and bursitis. J Am Acad Orthop Surg 1998;6(5):267-273.

     

     

18. Kuhne M, Boniquit N, Ghodadra N, et al. The snapping scapula: diagnosis and treatment. Arthroscopy 2009;25(11):1298-1311.

     

     

19. Lien SB, Shen PH, Lee CH, et al. The effect of endoscopic bursectomy with mini-open partial scapulectomy on snapping scapula syndrome. J Surg Res 2008;150(2):236-242.

     

     

20. Manske RC, Reiman MP, Stovak ML. Nonoperative and operative management of snapping scapula. Am J Sports Med 2004;32(6):1554-1565.

     

     

21. Mauclaire M. Craquements sous-scapulaires pathologiques traits par l’interposition musculaire interscapuothoracique. Bull Mem Soc Chir Paris 1904;30:164-168.

     

     

22. McCluskey G III, Bigliani L. Surgical management of refractory scapulothoracic bursitis. Orthop Trans 1991;15:801.

     

     

23. Milch H. Partial scapulectomy for snapping of the scapula. J Bone Joint Surg Am 1950;32-A(3):561-566.

     

     

24. Milch H. Snapping scapula. Clin Orthop 1961;20:139-150.

     

     

25. Millett PJ, Gaskill TR, Horan MP, et al. Technique and outcomes of arthroscopic scapulothoracic bursectomy and partial scapulectomy. Arthroscopy 2012;28(12):1776-1783.

     

     

26. Millett PJ, Pacheco IH, Gobezie R, et al. Management of recalcitrant scapulothoracic bursitis: endoscopic scapulothoracic bursectomy and scapuloplasty. Tech Shoulder Elbow Surg 2006;7:200-205.

     

     

27. Mozes G, Bickels J, Ovadia D, et al. The use of three-dimensional computed tomography in evaluating snapping scapula syndrome. Orthopedics 1999;22(11):1029-1033.

     

     

28. Nicholson GP, Duckworth MA. Scapulothoracic bursectomy for snapping scapula syndrome. J Shoulder Elbow Surg 2002;11(1):80-85.

     

     

29. O’Holleran J, Millett P, Warner JJ. Arthroscopic management of scapulothoracic disorders. In: Miller M, Cole B, eds. Textbook of Arthroscopy. Philadelphia: Saunders, 2004:277-287.

     

     

30. Pavlik A, Ang K, Coghlan J, et al. Arthroscopic treatment of painful snapping of the scapula by using a new superior portal. Arthroscopy 2003;19(6):608-612.

     

     

31. Pearse EO, Bruguera J, Massoud SN, et al. Arthroscopic management of the painful snapping scapula. Arthroscopy 2006;22(7):755-761.

     

     

32. Percy EC, Birbrager D, Pitt MJ. Snapping scapula: a review of the literature and presentation of 14 patients. Can J Surg 1988;31(4): 248-250.

     

     

33. Polguj M, Jędrzejewski K, Podgórski M, et al. A proposal for classification of the superior transverse scapular ligament: variable morphology and its potential influence on suprascapular nerve entrapment. J Shoulder Elbow Surg 2013;22(9):1265-1273.

     

     

    P.142

34. Rengachary SS, Burr D, Lucas S, et al. Suprascapular entrapment neuropathy: a clinical, anatomical and comparative study. Part 2: anatomical study. Neurosurgery 1979;5(4):447-451.

     

     

35. Richards RR, McKee MD. Treatment of painful scapulothoracic crepitus by resection of the superomedial angle of the scapula. A report of three cases. Clin Orthop Relat Res 1989;(247):111-116.

     

     

36. Ruland LJ III, Ruland CM, Matthews LS. Scapulothoracic anatomy for the arthroscopist. Arthroscopy 1995;11:52-56.

     

     

37. Sisto DJ, Jobe FW. The operative treatment of scapulothoracic bursitis in professional baseball pitchers. Am J Sports Med 1986;14(3): 192-194.

     

     

38. Takahara K, Uchiyama S, Nakagawa H, et al. Snapping scapula syndrome due to malunion of rib fractures: a case report. J Shoulder Elbow Surg 2004;13:95-98.

     

     

39. Totlis T, Konstantinidis GA, Karanassos MT, et al. Bony structures related to snapping scapula: correlation to gender, side and age. Surg Radiol Anat 2014;36(1):3-9.

     

     

40. van Riet RP, Van Glabbeek F. Arthroscopic resection of a symptomatic snapping subscapular osteochondroma. Acta Orthop Belg 2007;73(2):252-254.

     

     

41. Wood VE, Verska JM. The snapping scapula in association with the thoracic outlet syndrome. Arch Surg 1989;124(11):1335-1337.