Minimally Invasive Treatment for Scapulothoracic Disorders

Chapter 16 ## Arthroscopic Treatment of Scapulothoracic Disorders
Michael J. Huang and Peter J. Millett DEFINITION 1. Several terms have been used to describe the elements of scapulothoracic bursitis and crepitus, such as snapping scapula, washboard syndrome, scapulothoracic syndrome, and rolling scapula.
2. The first description of scapulothoracic crepitus is credited to Boinet in 1867.1
3. By 1904, Mauclaire5 had described three subclasses— froissement , frottement , and craquement —depending on the loudness and character of the sound.
4. Milch6 and then Kuhn et al4 added to the understanding by differentiating sounds of soft tissues ( frottement ) from those arising from an osseous lesion ( craquement or crepitus). ANATOMY 5. Major bursae
1. Infraserratus bursa located between the serratus anterior muscle and the chest wall
2. Supraserratus bursa located between the subscapularis and the serratus anterior muscles
6. Minor bursae
1. Not consistently identified on cadaveric or clinical studies
2. Adventitial in nature; thought to arise secondary to abnormal biomechanics of the scapulothoracic joint
3. Superomedial angle of the scapula
1. Infraserratus
2. Supraserratus
4. Spine of scapula
1. Trapezoid
5. Inferior angle of scapula
1. Infraserratus PATHOGENESIS 7. Scapulothoracic bursitis can be caused by atrophied or fibrotic muscle, anomalous muscle insertions, or elastofibroma (rare benign soft tissue tumor located on the chest wall).
8. Osteochondromas and malunited fractures of the ribs or scapula can also cause pathology in this articulation.
9. Infectious causes include tuberculosis or syphilis.
10. The tubercle of Luschka is a prominence at the superomedial aspect of the scapula that can be excessively hooked and can cause altered biomechanics.
11. Scoliosis or thoracic kyphosis can contribute to scapulothoracic crepitus.
12. Unrelated disorders include cervical radiculopathy, glenohumeral pathology, and periscapular strain. NATURAL HISTORY 13. Scapulothoracic disorders are often associated with repetitive overhead activities or with a history of trauma.
14. Constant motion leads to inflammation and a cycle of chronic bursitis and scarring. 134 15. Mechanical impingement and pain with motion are a result of tough fibrotic tissue, furthering the inflammatory cycle. PATIENT HISTORY AND PHYSICAL FINDINGS 16. Repetitive overhead activities or trauma
17. Palpable or audible crepitus over the involved area
18. Occasionally bilateral or positive family history
19. Localized tenderness over the inflamed area is most common.
1. Superomedial border is the most commonly affected area.
2. Inferior pole is also a common site of pathology.
20. Pseudowinging (nonneurologic etiology) may result from fullness over the involved area and compensation of scapular mechanics due to pain.
21. Crepitus alone, without pain, may be physiologic and not warrant treatment. IMAGING AND OTHER DIAGNOSTIC STUDIES 22. Tangential scapular views to identify bony anomalies
23. Computed tomography is controversial but can be helpful if osseous lesions are suspected and plain radiographs are normal.
24. Magnetic resonance imaging (MRI) is also controversial but can identify the size and location of bursal inflammation.
25. Injection of a corticosteroid and local anesthetic is helpful to confirm the diagnosis. DIFFERENTIAL DIAGNOSIS 26. Atrophied, fibrotic muscle or anomalous muscle
27. Malunited rib or scapular fracture
28. Mass (eg, elastofibroma, osteochondroma)
29. Infection (ie, tuberculosis, syphilis)
30. Scoliosis or kyphosis
31. Cervical spine radiculopathy
32. Glenohumeral disease NONOPERATIVE MANAGEMENT 33. Rest
34. Nonsteroidal anti-inflammatory
35. Activity modification
36. Physical therapy
1. Local modalities
2. Periscapular strengthening, emphasizing subscapularis and serratus anterior
3. Postural training
37. Figure 8 harness for kyphosis
38. Injection may be of benefit for both diagnosis and treatment. SURGICAL MANAGEMENT 39. Indicated for patients who have failed to respond to conservative therapy
40. Open treatment

Chapter 16 ARTHROSCOPIC TREATMENT OF SCAPULOTHORACIC DISORDERS135

FIG 1 • The arm behind the back in extension and internal rotation: the “chicken wing” position.

1. Has been used successfully in treatment of both bursitis7,9 and crepitus6,8
2. Requires fairly large exposure and subperiosteal dissection of the medial musculature, with repair back to bone after débridement of pathologic tissue is accomplished
3. Arthroscopic treatment
4. Minimizes morbidity of the exposure and facilitates early rehabilitation and return to function Preoperative Planning 42. If a bony mass is detected, computed tomography findings will help guide the planned resection. Positioning 1. The patient is placed in the prone position, with the arm behind the back in extension and internal rotation (the so-called chicken wing position; FIG 1 ). Approach 2. Decisions regarding open versus arthroscopic treatment for these disorders should be based on surgeon experience and comfort level. POSTOPERATIVE CARE 3. Sling for comfort
5. Gentle passive motion immediately
6. Active and active-assisted motion and isometric exercises are started at 4 weeks postoperatively.
7. Periscapular strengthening starts at 8 weeks postoperatively. OUTCOMES 7. No large series of arthroscopic treatment have been published.
8. Several smaller series have reported favorable outcomes after arthroscopic surgery.2,3 COMPLICATIONS 9. Pneumothorax
9. Infection
10. Inadequate resection, recurrence of symptoms

ARTHROSCOPIC PORTALS

1. The initial “safe” portal is 2 cm medial to the medial scapular edge at the level of the scapular spine, between the chest wall and serratus anterior ( TECH FIG 1A ).
2. Avoids dorsal scapular nerve and artery
3. The space is distended with 150 mL saline via spinal needle and then the portal is created.
4. After insertion of a 4.0-mm 30-degree arthroscope into the first portal, a second “working” portal is established under direct visualization ( TECH FIGS 1B and 1D ).
5. It is placed about 4 cm inferior to the first portal.

TECHNIQUES

1. A 6-mm cannula is inserted into this portal.
2. An additional superior portal can be placed as described by Chan et al1 ( TECH FIG 1C ).
3. Portals superior to the scapular spine place the dorsal scapular neurovascular structures, accessory spinal nerve, and transverse cervical artery at risk, however.
   
   
   
   --- A B C
   --- TECH FIG 1• Placement of the first arthroscopic portal ( A ), the second “working” arthroscopic portal ( B ), and the optional superior portal ( C ). D D. Arthroscopic view from the first portal. 136 Part 1 SPORTS MEDICINE • Section I SHOULDER
   
   
   
   
   

TECHNIQUES

RESECTION

1. A methodical approach to resection is needed because there are minimal anatomic landmarks.
2. Radiofrequency ablation and motorized shaving are used ( TECH FIG 2A,B ).
3. The surgeon proceeds medial to lateral and inferior to superior.
4. Spinal needles can be used to outline the medial border of the scapula ( TECH FIG 2C,D ).
5. Switching portals and the use of a 70-degree arthroscope may be necessary ( TECH FIG 2E,F ).
6. The superomedial angle of the scapula is identified by palpation through the skin.
7. Radiofrequency is used to detach the conjoined insertion of the rhomboids, levator scapulae, and supraspinatus from the bone.
8. A partial scapulectomy is performed using a motorized shaver and burr.
9. The arm should then be placed through a range of motion to assess the resection. A B C D TECH FIG 2 • A,B. Resection and débridement of the scapula. C,D. The spinal needle is used as a guide to the medial border of the scapula. E,F. Final E F débridement. PEARLS AND PITFALLS Portal placement
   Visualization
   Bursectomy
   Partial scapulectomy
10. The surgeon should consider the neurovascular structures and the thoracic structures.
11. The surgeon should enter parallel to the ribs and use a spinal needle to localize the portals.
12. More inferiorly placed portals are safer because the dorsal scapular nerve arborizes terminally.
13. Predistention
14. Epinephrine for vasoconstriction
15. Appropriate pump pressure
16. The surgeon should work expeditiously.
17. Inadvertent thoracotomy is avoided.
18. A complete bursectomy is performed.
19. The surgeon should avoid perforating the subscapularis muscle medially (bleeding).
20. Preoperative planning with computed tomography or three-dimensional computed tomography
21. Anatomy is localized with a spinal needle.
22. Adequate resection is performed.
    Chapter 16** ARTHROSCOPIC TREATMENT OF SCAPULOTHORACIC DISORDERS137