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Scapulothoracic Endoscopy for the Painful Snapping Scapula: Endoscopic Anatomy and Scapuloplasty Technique
Scapulothoracic Endoscopy for the Painful Snapping Scapula: Endoscopic Anatomy and Scapuloplasty Technique Deepak N. Bhatia, M.S.(Orth), D.N.B.(Orth)
Abstract: Chronic painful snapping scapula is characterized by inflammation and scarring of 1 or more bursae in the infraserratus space and is often refractory to conservative treatment. Surgical treatment involves excision of the bursae, as well as partial scapulectomy of the superomedial impinging region; both open and endoscopic approaches have been described with good results. Scapulothoracic endoscopy is technically difficult, and the potential complications can be serious. This report describes an endoscopic approach that can be performed with only 2 medial parascapular portals for visualization and instrumentation. The endoscopic anatomy of the infraserratus space is revisited, and 3 anatomic landmarks (serratus anterior, subspinous bursal curtain, and superomedial bony angle) are identified for safe dissection and intraoperative orientation. The surgical field is subdivided into 3 anatomic zones (superomedial space, subspinous space, and scapular bony angle), and the anatomic boundaries of these zones are demonstrated. The decompression procedure is subdivided into 4 stages (superomedial bursectomy, subspinous adhesiolysis, tuberoplasty, and scapuloplasty), and a measured resection technique for scapuloplasty is performed. The use of newer motorized rasps permits optimal bony resection, and additional portals are unnecessary. Overall, the step-by-step technique provides a methodical approach for safety, reproducibility, and optimization of the procedure.
T
he painful snapping scapula is a chronic disabling disorder of the scapulothoracic articulation and is characterized by painful crepitus and scapular dyskinesia. Structural and postural abnormalities predispose to development of adhesions and bursitis in the subspinous and superomedial infraserratus regions of the scapula. Structural bony abnormalities described in the literature include the Luschka tubercle and aberrant muscle attachments; in addition, an association between bony scapular morphology and snapping scapula has been suggested.1-3 Failure of conservative treatment and the presence of an identifiable structural causative lesion are indications for surgical decompression.4 Endoscopic-assisted and all-endoscopic scapulothoracic bursectomy with or without partial From the Department of Orthopaedic Surgery, Seth GS Medical College, and King Edward VII Memorial Hospital, Mumbai, India. The author reports that he has no conflicts of interest in the authorship and publication of this article. Received March 1, 2015; accepted May 21, 2015. Address correspondence to Deepak N. Bhatia, M.S.(Orth), D.N.B.(Orth), Department of Orthopaedic Surgery, Seth GS Medical College, and King Edward VII Memorial Hospital, Parel, Mumbai 400012, India. E-mail: [email protected] Ó 2015 by the Arthroscopy Association of North America 2212-6287/15206/$36.00 http://dx.doi.org/10.1016/j.eats.2015.05.010
scapular resection has been described and is successful in approximately two-thirds of patients.5-7 However, scapulothoracic endoscopy is technically difficult, and this is attributable to lack of a potentially distensible space, as well as the paucity of intraoperative anatomic landmarks for endoscopic orientation. Moreover, the proximity to the chest wall, apical pleura, and several neurovascular structures makes endoscopic exploration challenging.8,9 The purpose of this report is to describe a step-by-step technique for safe scapulothoracic endoscopy using standard anatomic landmarks to guide dissection. The technique involves 2 portals for access to 2 scapulothoracic spaces (superomedial and subspinous), and the decompression procedure is subdivided into 4 stages (superomedial bursectomy, subspinous adhesiolysis, tuberoplasty, and scapuloplasty). The endoscopic anatomy of the infraserratus space is revisited, and tips and pearls for safe dissection and reproducibility are described.
Technique Clinical examination and preoperative imaging (magnetic resonance imaging [MRI] and computed tomography [CT] scans) are used to identify the bony and soft-tissue pathologic conditions. The procedure is
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performed with the patient in the prone position, and the arm is extended and internally rotated behind the back (chicken-wing position) (Fig 1). This position lifts the medial border of the scapula and opens the scapulothoracic spaces for endoscopic exploration. External bony landmarks (superomedial scapular angle, medial scapular border, and scapular spine) and 2 medial parascapular portals are marked. The superomedial and subspinous spaces in the infraserratus region are infiltrated with saline solution for initial distension. A 2.9-mm arthroscope and sheath (2.9 152 mm; ConMed Linvatec, Largo, FL) are used, and a fluid pump (60 mm Hg) is necessary for adequate distension. The key steps and surgical pearls of the technique are summarized in Tables 1 and 2, respectively, and the steps are demonstrated in Video 1. Step 1: Portal Placement Two portals are marked in the periscapular safe zones.8,9 The inferior scapular portal is placed 4 mm below the scapular spine and 2 to 3 cm medial to the medial scapular border. The arthroscope sheath with a blunt obturator is angled slightly inferiorly and perpendicular to the medial scapular border and is passed into the infraserratus subspinous space. Thereafter the sheath is angled superiorly toward the superomedial scapular angle
Fig 1. Overview of chicken-wing position and external anatomic landmarks. The draping should extend medially to the thoracic spinous processes (dotted line). Inferior (I) and superior (S) scapular portal sites (x) are marked. An additional superior portal (B) is shown for reference and is not used in this technique. The superomedial space (SM, black arrow) and subspinous space (white arrow) are shown. (INF, inferior; ip, inferior scapula pole; LAT, lateral; MED, medial; SC, scapula; sp, scapular spine; SUP, superior.)
Table 1. Key Steps of Procedure Correct patient positioning and infraserratus space infiltration with saline solution are vital for accurate portal placement and visualization. Portals should be placed at or inferior to the scapular spine and 2-3 cm away from the medial scapular border. The first anatomic landmark is the serratus anterior, and its ventral surface should be identified for orientation. Superomedial bursectomy is performed without violating this muscle or its fascial covering. The second anatomic landmark is the subspinous bursal curtain, and excision of this structure provides access to the subspinous space. Subspinous bursectomy and adhesiolysis are performed in this region. The third anatomic landmark is the superomedial bony angle, and this is identified using an outside-in spinal needle for orientation. The tubercle of Luschka or any bony prominence is identified in this region. Tuberoplasty is performed using a motorized rasp (PoweRasp) and a burr. The tubercle is thinned out to lie flush with the surrounding bone. Scapuloplasty is performed using the measured resection technique; 5-10 mm of bone is resected as described. Final assessment of the debrided spaces is performed by reversing the portals or with a 70 arthroscope. Thorough lavage is necessary to clear the bony particle debris.
and is advanced into the superomedial space. The superior scapular portal is placed 4 to 6 cm superior to the inferior scapular portal and 2 to 3 cm medial to the medial scapular border. The exact position is determined using a spinal needle, and a smooth cannula (Universal Cannula, 5.5 70 mm; ConMed Linvatec) is advanced into the superomedial space under direct vision (Fig 2). Step 2: Superomedial Bursectomy A blunt probe is passed through the superior scapular portal cannula and is used for initial dissection to visualize the superomedial space. The serratus anterior muscle forms the roof of this space and is the first anatomic landmark for orientation (Fig 3). The floor of the space is the posteromedial chest wall, and the ribs and intercostal spaces are palpated gently with the blunt probe. Next, a radiofrequency probe (VAPR; DePuy Mitek, Raynham, MA) is introduced through the superior scapular portal cannula, and the bursa is excised (Fig 4A). Fibrous adhesions are excised with a motorized shaver blade (4-mm SabreTooth; Arthrex, Naples, FL). The superomedial space bursectomy is extended inferiorly to the subspinous region, and this space is accessed through the subspinous “bursal curtain” as described in step 3 (Fig 4B). Step 3: Subspinous Bursectomy and Adhesiolysis The subspinous space is the region under the scapular spine and is separated from the superomedial space by the bursal curtain. The bursal curtain is an area of bursal adhesions that can be identified in more 50% of
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Table 2. Technical Pearls for Key Steps of Procedure Step Portals and visualization
Bursectomy and adhesiolysis
Tubercle exposure
Tuberoplasty
Scapuloplasty
Pearls Lateral pressure to the shoulder exaggerates the scapular winging and facilitates correct portal placement. Insufflation with saline solution distends the spaces and aids visualization. The inferior scapular portal is placed just 4 cm inferior to the scapular spine. This position permits adequate visualization, especially if the concavity of the medial scapula is excessive. The superior scapular portal is placed at or just above the scapular spine to avoid the dorsal scapular neurovascular structures. A spinal needle is used to confirm adequate access and ease of triangulation. A 2.9-mm, 30 arthroscope is preferred for ease of placement and provides good visualization; however, the technique can be performed with a 4-mm arthroscope. A 70 arthroscope provides excellent views and eliminates the need to change to the superior portal for viewing; however, it also renders orientation difficult and should be used only once the surgeon is familiar with the technique. The infraserratus space is inflamed and vascular, and even a minor bleed can restrict visualization. Bleeding can be minimized by as follows: A radiofrequency probe is preferable to a shaver to minimize bleeding. The first 2 anatomic landmarks (serratus anterior and subspinous bursal curtain) should be identified for safe bursectomy. The dissection should not violate the ventral fascia of the serratus anterior to avoid bleeding. The subspinous bursal curtain should be identified and excised to gain access to the subspinous space. Complete bursectomy involves clearance of both spaces. Scapular arteries can be identified in the subspinous space, and these should be protected to prevent torrential bleeding. The radiofrequency probe tip is always placed facing away from the intercostal surface. Complete bursal clearance is necessary to prevent visual obstruction. The spinal needle is used to guide dissection. First, the medial border is exposed, and then, the superior border is demarcated. The fascia attached to the borders is preserved to prevent damage to the periscapular muscle attachments. Similarly, the serratus anterior superior is preserved, and dissection is limited to its superior border. Aberrant muscle attachments should be excised. The PoweRasp is a useful alternative to a burr; soft-tissue entanglement in the rotating burr is common, and this is prevented by using the PoweRasp. Initial decortication is performed until a broad bleeding surface is seen. Thereafter, the remaining bony prominence is rasped or burred until this area is flush with the surrounding bone. Any sharp edges are burred and beveled. The superomedial angle is resected along the medial and superior borders in gradual increments. This permits quantification of the bone that is removed. The 4-mm burr is used to guide resection. Usually, resection of an amount equivalent to twice the width of the burr (8 mm) can be safely performed without detaching the fascial attachments of periscapular muscles. The debris from bony resection settles deep in the infraserratus region, and a shaver blade is used to clear these particles from the lateral and inferior infraserratus regions.
endoscopies and is the second anatomic landmark for orientation. Excision of the bursal curtain provides access to the subspinous space for exploration and adhesiolysis. One to two large scapular arteries emanating from the scapular anastomosis can be seen pulsating in the subspinous space, and these should be identified and protected at all times (Fig 5). Step 4: Demarcation of Superomedial Tubercle The superomedial region of the scapula consists of a 2-cm bare costal area; the inferior extent of this area is marked by the superior border of the serratus anterior superior. In most cases this area is covered with thick bursal tissue and adhesions. In some cases aberrant muscle fibers may be seen covering this area in part or even entirely (Fig 6A).10 The tubercle of Luschka is a bony “bump” in this area and is present in 2% to 3% of the scapulae in anatomic studies.2,3 The tubercle is not visible unless the covering soft tissues are excised. A radiofrequency probe is used, through the superior
scapular portal cannula, to excise the scarred bursal tissue on the ventral surface of the bare area. A spinal needle is passed in an outside-in manner at the level of the skin marking of the superomedial angle. The needle identifies the bony angle; this point forms the third anatomic landmark and demarcates the superior and medial borders from each other. Thereafter the dissection is extended to completely expose the tubercle and its borders for 1 to 2 cm. The inferior extent of the exposure is marked by the superior border of the serratus anterior superior muscle (Fig 6B). Step 5: Tuberoplasty Tuberoplasty is performed by co-planing the prominent bony protuberance; this is achieved with a motorized rasp (PoweRasp, 4 mm; Arthrex) and a 4-mm burr (Arthrex). A straight or angled shaver blade (4-mm SabreTooth) is used initially to excise any remaining soft tissues. The PoweRasp is used in the oscillating mode initially for decortication of the
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Fig 2. (A) The inferior scapular portal (I) is placed 2 to 3 cm medial to the medial scapular border (SC). The sheath (Ar) is directed superiorly toward the superomedial space (SM) and slightly ventral to avoid penetration of the supraserratus space. The inset shows the insufflation of the subspinous space with saline solution for distention prior to portal incision. Lateral pressure is applied by the surgeon to make the medial border prominent. (B) The superior scapular portal is placed 4 cm superior to the inferior scapular portal and 2 to 3 cm medial to the medial scapular border. The portal should not be placed above the scapular spine (SP). The probe (Pr) is passed through the superior scapular portal for blunt dissection. The inset shows the insufflation of the superomedial space with saline solution for distention prior to portal incision. Lateral pressure is applied by the surgeon (H) to make the medial border prominent. (AR, arthroscope sheath; ip, inferior scapula pole; S, superior scapular portal.)
tubercle and then in forward mode for rapid bone excision. Further resection is performed using a combination of a burr and shaver blade (Fig 7). Step 6: Scapuloplasty Partial scapulectomy involves gradual and measured resection of the borders of the superomedial angle; a
Fig 3. The first anatomic landmark to be identified in the infraserratus space is the serratus anterior muscle (SRA). The probe (PR) is used to palpate the muscle and the superomedial angle (SUP), and blunt dissection is used to clear the bursa (BS). The subspinous space is inferior (INF), and the chest wall (CH) forms the floor of this space. The viewing portal is the inferior scapular portal, and the working portal is the superior scapular portal, with a 30 view.
burr is used to excise 5 to 10 mm of bone from the medial border, and resection is then extended to the superior border. The fascial attachments are visualized and preserved to prevent periscapular muscle detachment. Resection is limited to 10 mm; however, if necessary, further bone may be resected in gradual increments (Fig 8). Step 7: Final Assessment and Lavage The arthroscope is shifted to the superior scapular portal; this permits an “end-on” view of the superomedial region, and any bony spurs and sharp borders can be identified and resected (Fig 9). The superior scapular portal also permits a better view of the subspinous region, and adequacy of clearance and resection is confirmed. The debris generated from the resection can become deposited in these spaces, and thorough lavage is necessary to clear this. Postoperative chest radiographs are necessary to confirm integrity of the pleura and to rule out a pneumothorax. A bulky dressing is used for the first 2 postoperative days and is changed to a lighter portalsite dressing thereafter. Use of a sling is necessary for comfort only and is discarded in 1 to 2 days. The rehabilitation protocol involves early passive and active range-of-motion exercises (weeks 2 to 4) and simultaneous gradual strengthening of the periscapular muscles. Full range is achieved in 2 to 3 weeks, and light work is permitted. Return to heavy work and sports is permitted only after 3 months of rehabilitation.
Discussion Snapping scapula is a clinical diagnosis and is characterized by 3 key findings: (1) chronic pain and tenderness along the superomedial scapular border, (2)
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Fig 4. (A) Bursectomy is performed with a radiofrequency probe passed through the superior (S) portal cannula (Cn), and the arthroscope (Ar) is in the inferior (I) portal. A spinal needle (N) is passed in the region of the superomedial angle (SM) for orientation. (B) Superomedial space bursectomy is performed with the radiofrequency probe (RF) facing away from the chest wall (CH). The bursectomy extends from the superomedial angle (SMA) down to the subspinous bursal curtain (CT). The viewing portal is the inferior scapular portal, and the working portal is the superior scapular portal, with a 30 view. (INF, inferior; LAT, lateral; MED, medial; SC, scapula; SRA, serratus anterior; SUP, superior.)
Fig 5. (A) The second anatomic landmark is the subspinous bursal curtain (CT), and excision of this bursal thickening shows the subspinous space (asterisk). The serratus anterior (SRA) forms the roof of this space, and the chest wall (CH) is at the floor. (B) Complete excision of the bursal curtain permits visualization of the subspinous space adhesions (SSS). (C) Scapular vessels (AR) are present in the subspinous space and are seen coursing through the bursal tissue and toward the serratus anterior. The viewing portal is the inferior scapular portal, and the working portal is the superior scapular portal, with a 30 view. (in, inferior; RF, radiofrequency probe; SMA, superomedial angle; sp, superior.)
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Fig 6. (A) A rare aberrant serratus anterior superior (SRA) is seen completely covering the superomedial scapular angle (SMA). The superior 2 cm of the aberrant attachment should be excised to permit a clear view of the superomedial corner. (B) The prominent bony Luschka tubercle (TL) is exposed by excision of soft tissue superior to the serratus anterior. The superomedial scapular tip (asterisk) is the third anatomic landmark; this is located using an outside-in spinal needle (N) and demarcates the medial (M) and superior (Su) borders. The viewing portal is the inferior scapular portal, and the working portal is the superior scapular portal, with a 30 view. (b, bursa; CH, chest wall.)
periscapular crepitus that is palpable or sometimes even audible, and (3) scapular dyskinesia. MRI may show the pathologic bursa, as well as bony or muscular edema; however, its utility in the diagnostic and therapeutic algorithm has not been shown. Bony morphology can be evaluated using MRI and 3-dimensional CT scans, and real-time 4-dimensional CT scans can show additional areas of bony contact.1,11 Scapulothoracic endoscopy is effective in the treatment of snapping scapula; however, the procedure is not widely performed because of the technical
challenges and potentially dangerous complications.4-9 This report is a detailed guide to the steps of scapulothoracic endoscopy and is based on the identification of 3 anatomic landmarks (serratus anterior, subspinous bursal curtain, and superomedial bony angle). The resection area is subdivided into 3 zones (superomedial space, subspinous space, and scapular bony angle), and the procedure is described in 4 stages for optimal debridement and reproducibility. Strict adherence to these guidelines is necessary for optimal and safe surgery in this region.
Fig 7. (A) The tubercle of Luschka is seen prior to tuberoplasty. Excision of the soft tissue over the tubercle (TL) and in the superomedial space is completed with a shaver (SH), and the spinal needle (N) is used for orientation. (B) Tuberoplasty is performed with a motorized PoweRasp (PW), and the Luschka tubercle (TL) is thinned out until it is flush with the surrounding bone. The viewing portal is the inferior scapular portal, and the working portal is the superior scapular portal, with a 30 view. (CH, chest wall; SRA, serratus anterior.)
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Fig 8. (A) Measured resection for scapuloplasty involves burring the medial border (M; black arrows) and the superior edge (SU; white arrows) of the superomedial scapular angle. (B) The thinned-out tubercle (TL) is further burred to complete the resection. The fascial layer of the periscapular muscles (white arrows) is preserved and is continuous with the borders of the superomedial angle (black arrows). The viewing portal is the inferior scapular portal, and the working portal is the superior scapular portal, with a 30 view. (BR, motorized burr; TL, Luschka tubercle.)
The amount of bony resection is controversial, and the resection amount ranges between 1 and 7 cm.12,13 Bell and colleagues14-16 have described a safe zone for arthroscopic resection of the superomedial scapular border and have suggested an alternative superior portal (Bell portal) for bony resection. However, Aggarwal et al.17 have suggested that the suprascapular nerve may be vulnerable in 14% of resections, and Blønd and Rechter18 have described 1 long thoracic nerve lesion that probably occurred because of trauma from a shaver blade in the superior Bell portal. The technique described in this article and Video 1 uses only 2 portals, thereby minimizing the risk of neurovascular and muscular violation. In addition, a measured resection technique is used to quantify the amount of
Fig 9. Reversal of the portals permits visualization (CAM) of the resection area and subspinous region through the superior scapular portal (S; viewing portal). The area can be probed (PB) through the inferior portal (I; working portal). The adequacy of resection and presence of debris can be assessed. (in, inferior; LAT, lateral; N, spinal needle; Su, superior.)
Table 3. Advantages and Pitfalls of Technique Advantages The scapulothoracic endoscopy technique avoids the need for an open approach and its subsequent morbidity. Only 2 portals are required for effective and complete management. Complete bursectomy and adhesiolysis can be performed by accessing the entire pathologic infraserratus space. Newer instrumentation (PoweRasp, angled shaver blades) simplifies and optimizes the tuberoplasty and scapuloplasty procedures. The measured resection technique for scapuloplasty permits precise and systematic scapular resection. Adequate tuberoplasty decreases the bony thickness and simplifies subsequent resection. The levator scapulae attaches to the superomedial margin, and the rhomboid minor attaches to the spinous region of the medial scapular border. The measured resection technique limits the resection to 5-10 mm; fascial attachments to the scapular angle are thereby preserved, and this maintains continuity of the important periscapular muscles. The step-by-step approach simplifies the procedure and shortens the learning curve for the technique. Pitfalls Precise portal placement is crucial. Incorrect angulation can result in intrathoracic penetration of the sheath. Alternately, the sheath may enter the supraserratus space between the subscapularis and serratus anterior, with potentially dangerous neurovascular complications. The dorsal scapular and spinal accessory nerves are close to the medial scapular border. Incorrect portal placement may damage these important nerves. The apical pleura is in proximity to the superomedial angle. Damage to the pleura during bursectomy can lead to a pneumothorax. Meticulous intraoperative monitoring should be routinely performed and a chest radiograph should be routinely obtained at the end of the procedure to rule out pneumothorax. Scapular arteries are present and can be identified in the subspinous space. Damage to these vessels can lead to torrential hemorrhage, and the procedure may have to be abandoned. Excessive resection can result in detachment of the levator scapulae and rhomboid minor muscles and can worsen the snapping and scapular dyskinesia in the postoperative period. Inadequate debridement will result in persistence or recurrence of the painful snapping, as well as inadequate symptomatic relief.
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bone resected. In my experience, the 2-portal technique provides an optimal viewing angle, and a third portal for resection is avoided by using new instrumentation such as the PoweRasp. The overall advantages and pitfalls of the procedure are summarized in Table 3.
References 1. Spiegl UJ, Petri M, Smith SW, Ho CP, Millett PJ. Association between scapula bony morphology and snapping scapula syndrome. J Shoulder Elbow Surg in press, available online 14 February, 2015. doi:10.1016/j.jse.2014.12.034. 2. Totlis T, Konstantinidis GA, Karanassos MT, Sofidis G, Anastasopoulos N, Natsis K. Bony structures related to snapping scapula: Correlation to gender, side and age. Surg Radiol Anat 2014;36:3-9. 3. Aggarwal A, Wahee P, Harjeet, Aggarwal AK, Sahni D. Variable osseous anatomy of costal surface of scapula and its implications in relation to snapping scapula syndrome. Surg Radiol Anat 2011;33:135-140. 4. Kuhne M, Boniquit N, Ghodadra N, Romeo AA, Provencher MT. The snapping scapula: Diagnosis and treatment. Arthroscopy 2009;25:1298-1311. 5. Millett PJ, Gaskill TR, Horan MP, van der Meijden OA. Technique and outcomes of arthroscopic scapulothoracic bursectomy and partial scapulectomy. Arthroscopy 2012;28:1776-1783. 6. Pearse EO, Bruguera J, Massoud SN, Sforza G, Copeland SA, Levy O. Arthroscopic management of the painful snapping scapula. Arthroscopy 2006;22: 755-761. 7. Lehtinen JT, Tetreault P, Warner JJ. Arthroscopic management of painful and stiff scapulothoracic articulation. Arthroscopy 2003;19:E28.
8. Ruland LJ III, Ruland CM, Matthews LS. Scapulothoracic anatomy for the arthroscopist. Arthroscopy 1995;11:52-56. 9. Wascher DC, Aboka A, Menzer H. Safety of portal placement for scapulothoracic arthroscopy. Arthroscopy 2011;27:e93-e94. 10. Boyle MJ, Misur P, Youn SM, Ball CM. The superomedial bare area of the costal scapula surface: A possible cause of snapping scapula syndrome. Surg Radiol Anat 2013;35:9598. 11. Bell SN, Troupis JM, Miller D, Alta TD, Coghlan JA, Wijeratna MD. Four-dimensional computed tomography scans facilitate preoperative planning in snapping scapula syndrome. J Shoulder Elbow Surg 2015;24:e83-e90. 12. Lehtinen JT, Macy JC, Cassinelli E, Warner JJ. The painful scapulothoracic articulation: Surgical management. Clin Orthop Relat Res 2004:99-105. 13. Oizumi N, Suenaga N, Minami A. Snapping scapula caused by abnormal angulation of the superior angle of the scapula. J Shoulder Elbow Surg 2004;13:115-118. 14. 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;17:647-649. 15. Chan BK, Chakrabarti AJ, Bell SN. An alternative portal for scapulothoracic arthroscopy. J Shoulder Elbow Surg 2002;11:235-238. 16. Pavlik A, Ang K, Coghlan J, Bell S. Arthroscopic treatment of painful snapping of the scapula by using a new superior portal. Arthroscopy 2003;19:608-612. 17. Aggarwal A, Wahee P, Aggarwal AK, Kaur H, Sahni D. Anatomical considerations for safe scapular resection in snapping scapula syndrome. Surg Radiol Anat 2012;34:43-47. 18. Blønd L, Rechter S. Arthroscopic treatment for snapping scapula: A prospective case series. Eur J Orthop Surg Traumatol 2014;24:159-164.
Abstract: Chronic painful snapping scapula is characterized by inflammation and scarring of 1 or more bursae in the infraserratus space and is often refractory to conservative treatment. Surgical treatment involves excision of the bursae, as well as partial scapulectomy of the superomedial impinging region; both open and endoscopic approaches have been described with good results. Scapulothoracic endoscopy is technically difficult, and the potential complications can be serious. This report describes an endoscopic approach that can be performed with only 2 medial parascapular portals for visualization and instrumentation. The endoscopic anatomy of the infraserratus space is revisited, and 3 anatomic landmarks (serratus anterior, subspinous bursal curtain, and superomedial bony angle) are identified for safe dissection and intraoperative orientation. The surgical field is subdivided into 3 anatomic zones (superomedial space, subspinous space, and scapular bony angle), and the anatomic boundaries of these zones are demonstrated. The decompression procedure is subdivided into 4 stages (superomedial bursectomy, subspinous adhesiolysis, tuberoplasty, and scapuloplasty), and a measured resection technique for scapuloplasty is performed. The use of newer motorized rasps permits optimal bony resection, and additional portals are unnecessary. Overall, the step-by-step technique provides a methodical approach for safety, reproducibility, and optimization of the procedure.
T
he painful snapping scapula is a chronic disabling disorder of the scapulothoracic articulation and is characterized by painful crepitus and scapular dyskinesia. Structural and postural abnormalities predispose to development of adhesions and bursitis in the subspinous and superomedial infraserratus regions of the scapula. Structural bony abnormalities described in the literature include the Luschka tubercle and aberrant muscle attachments; in addition, an association between bony scapular morphology and snapping scapula has been suggested.1-3 Failure of conservative treatment and the presence of an identifiable structural causative lesion are indications for surgical decompression.4 Endoscopic-assisted and all-endoscopic scapulothoracic bursectomy with or without partial From the Department of Orthopaedic Surgery, Seth GS Medical College, and King Edward VII Memorial Hospital, Mumbai, India. The author reports that he has no conflicts of interest in the authorship and publication of this article. Received March 1, 2015; accepted May 21, 2015. Address correspondence to Deepak N. Bhatia, M.S.(Orth), D.N.B.(Orth), Department of Orthopaedic Surgery, Seth GS Medical College, and King Edward VII Memorial Hospital, Parel, Mumbai 400012, India. E-mail: [email protected] Ó 2015 by the Arthroscopy Association of North America 2212-6287/15206/$36.00 http://dx.doi.org/10.1016/j.eats.2015.05.010
scapular resection has been described and is successful in approximately two-thirds of patients.5-7 However, scapulothoracic endoscopy is technically difficult, and this is attributable to lack of a potentially distensible space, as well as the paucity of intraoperative anatomic landmarks for endoscopic orientation. Moreover, the proximity to the chest wall, apical pleura, and several neurovascular structures makes endoscopic exploration challenging.8,9 The purpose of this report is to describe a step-by-step technique for safe scapulothoracic endoscopy using standard anatomic landmarks to guide dissection. The technique involves 2 portals for access to 2 scapulothoracic spaces (superomedial and subspinous), and the decompression procedure is subdivided into 4 stages (superomedial bursectomy, subspinous adhesiolysis, tuberoplasty, and scapuloplasty). The endoscopic anatomy of the infraserratus space is revisited, and tips and pearls for safe dissection and reproducibility are described.
Technique Clinical examination and preoperative imaging (magnetic resonance imaging [MRI] and computed tomography [CT] scans) are used to identify the bony and soft-tissue pathologic conditions. The procedure is
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performed with the patient in the prone position, and the arm is extended and internally rotated behind the back (chicken-wing position) (Fig 1). This position lifts the medial border of the scapula and opens the scapulothoracic spaces for endoscopic exploration. External bony landmarks (superomedial scapular angle, medial scapular border, and scapular spine) and 2 medial parascapular portals are marked. The superomedial and subspinous spaces in the infraserratus region are infiltrated with saline solution for initial distension. A 2.9-mm arthroscope and sheath (2.9 152 mm; ConMed Linvatec, Largo, FL) are used, and a fluid pump (60 mm Hg) is necessary for adequate distension. The key steps and surgical pearls of the technique are summarized in Tables 1 and 2, respectively, and the steps are demonstrated in Video 1. Step 1: Portal Placement Two portals are marked in the periscapular safe zones.8,9 The inferior scapular portal is placed 4 mm below the scapular spine and 2 to 3 cm medial to the medial scapular border. The arthroscope sheath with a blunt obturator is angled slightly inferiorly and perpendicular to the medial scapular border and is passed into the infraserratus subspinous space. Thereafter the sheath is angled superiorly toward the superomedial scapular angle
Fig 1. Overview of chicken-wing position and external anatomic landmarks. The draping should extend medially to the thoracic spinous processes (dotted line). Inferior (I) and superior (S) scapular portal sites (x) are marked. An additional superior portal (B) is shown for reference and is not used in this technique. The superomedial space (SM, black arrow) and subspinous space (white arrow) are shown. (INF, inferior; ip, inferior scapula pole; LAT, lateral; MED, medial; SC, scapula; sp, scapular spine; SUP, superior.)
Table 1. Key Steps of Procedure Correct patient positioning and infraserratus space infiltration with saline solution are vital for accurate portal placement and visualization. Portals should be placed at or inferior to the scapular spine and 2-3 cm away from the medial scapular border. The first anatomic landmark is the serratus anterior, and its ventral surface should be identified for orientation. Superomedial bursectomy is performed without violating this muscle or its fascial covering. The second anatomic landmark is the subspinous bursal curtain, and excision of this structure provides access to the subspinous space. Subspinous bursectomy and adhesiolysis are performed in this region. The third anatomic landmark is the superomedial bony angle, and this is identified using an outside-in spinal needle for orientation. The tubercle of Luschka or any bony prominence is identified in this region. Tuberoplasty is performed using a motorized rasp (PoweRasp) and a burr. The tubercle is thinned out to lie flush with the surrounding bone. Scapuloplasty is performed using the measured resection technique; 5-10 mm of bone is resected as described. Final assessment of the debrided spaces is performed by reversing the portals or with a 70 arthroscope. Thorough lavage is necessary to clear the bony particle debris.
and is advanced into the superomedial space. The superior scapular portal is placed 4 to 6 cm superior to the inferior scapular portal and 2 to 3 cm medial to the medial scapular border. The exact position is determined using a spinal needle, and a smooth cannula (Universal Cannula, 5.5 70 mm; ConMed Linvatec) is advanced into the superomedial space under direct vision (Fig 2). Step 2: Superomedial Bursectomy A blunt probe is passed through the superior scapular portal cannula and is used for initial dissection to visualize the superomedial space. The serratus anterior muscle forms the roof of this space and is the first anatomic landmark for orientation (Fig 3). The floor of the space is the posteromedial chest wall, and the ribs and intercostal spaces are palpated gently with the blunt probe. Next, a radiofrequency probe (VAPR; DePuy Mitek, Raynham, MA) is introduced through the superior scapular portal cannula, and the bursa is excised (Fig 4A). Fibrous adhesions are excised with a motorized shaver blade (4-mm SabreTooth; Arthrex, Naples, FL). The superomedial space bursectomy is extended inferiorly to the subspinous region, and this space is accessed through the subspinous “bursal curtain” as described in step 3 (Fig 4B). Step 3: Subspinous Bursectomy and Adhesiolysis The subspinous space is the region under the scapular spine and is separated from the superomedial space by the bursal curtain. The bursal curtain is an area of bursal adhesions that can be identified in more 50% of
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Table 2. Technical Pearls for Key Steps of Procedure Step Portals and visualization
Bursectomy and adhesiolysis
Tubercle exposure
Tuberoplasty
Scapuloplasty
Pearls Lateral pressure to the shoulder exaggerates the scapular winging and facilitates correct portal placement. Insufflation with saline solution distends the spaces and aids visualization. The inferior scapular portal is placed just 4 cm inferior to the scapular spine. This position permits adequate visualization, especially if the concavity of the medial scapula is excessive. The superior scapular portal is placed at or just above the scapular spine to avoid the dorsal scapular neurovascular structures. A spinal needle is used to confirm adequate access and ease of triangulation. A 2.9-mm, 30 arthroscope is preferred for ease of placement and provides good visualization; however, the technique can be performed with a 4-mm arthroscope. A 70 arthroscope provides excellent views and eliminates the need to change to the superior portal for viewing; however, it also renders orientation difficult and should be used only once the surgeon is familiar with the technique. The infraserratus space is inflamed and vascular, and even a minor bleed can restrict visualization. Bleeding can be minimized by as follows: A radiofrequency probe is preferable to a shaver to minimize bleeding. The first 2 anatomic landmarks (serratus anterior and subspinous bursal curtain) should be identified for safe bursectomy. The dissection should not violate the ventral fascia of the serratus anterior to avoid bleeding. The subspinous bursal curtain should be identified and excised to gain access to the subspinous space. Complete bursectomy involves clearance of both spaces. Scapular arteries can be identified in the subspinous space, and these should be protected to prevent torrential bleeding. The radiofrequency probe tip is always placed facing away from the intercostal surface. Complete bursal clearance is necessary to prevent visual obstruction. The spinal needle is used to guide dissection. First, the medial border is exposed, and then, the superior border is demarcated. The fascia attached to the borders is preserved to prevent damage to the periscapular muscle attachments. Similarly, the serratus anterior superior is preserved, and dissection is limited to its superior border. Aberrant muscle attachments should be excised. The PoweRasp is a useful alternative to a burr; soft-tissue entanglement in the rotating burr is common, and this is prevented by using the PoweRasp. Initial decortication is performed until a broad bleeding surface is seen. Thereafter, the remaining bony prominence is rasped or burred until this area is flush with the surrounding bone. Any sharp edges are burred and beveled. The superomedial angle is resected along the medial and superior borders in gradual increments. This permits quantification of the bone that is removed. The 4-mm burr is used to guide resection. Usually, resection of an amount equivalent to twice the width of the burr (8 mm) can be safely performed without detaching the fascial attachments of periscapular muscles. The debris from bony resection settles deep in the infraserratus region, and a shaver blade is used to clear these particles from the lateral and inferior infraserratus regions.
endoscopies and is the second anatomic landmark for orientation. Excision of the bursal curtain provides access to the subspinous space for exploration and adhesiolysis. One to two large scapular arteries emanating from the scapular anastomosis can be seen pulsating in the subspinous space, and these should be identified and protected at all times (Fig 5). Step 4: Demarcation of Superomedial Tubercle The superomedial region of the scapula consists of a 2-cm bare costal area; the inferior extent of this area is marked by the superior border of the serratus anterior superior. In most cases this area is covered with thick bursal tissue and adhesions. In some cases aberrant muscle fibers may be seen covering this area in part or even entirely (Fig 6A).10 The tubercle of Luschka is a bony “bump” in this area and is present in 2% to 3% of the scapulae in anatomic studies.2,3 The tubercle is not visible unless the covering soft tissues are excised. A radiofrequency probe is used, through the superior
scapular portal cannula, to excise the scarred bursal tissue on the ventral surface of the bare area. A spinal needle is passed in an outside-in manner at the level of the skin marking of the superomedial angle. The needle identifies the bony angle; this point forms the third anatomic landmark and demarcates the superior and medial borders from each other. Thereafter the dissection is extended to completely expose the tubercle and its borders for 1 to 2 cm. The inferior extent of the exposure is marked by the superior border of the serratus anterior superior muscle (Fig 6B). Step 5: Tuberoplasty Tuberoplasty is performed by co-planing the prominent bony protuberance; this is achieved with a motorized rasp (PoweRasp, 4 mm; Arthrex) and a 4-mm burr (Arthrex). A straight or angled shaver blade (4-mm SabreTooth) is used initially to excise any remaining soft tissues. The PoweRasp is used in the oscillating mode initially for decortication of the
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Fig 2. (A) The inferior scapular portal (I) is placed 2 to 3 cm medial to the medial scapular border (SC). The sheath (Ar) is directed superiorly toward the superomedial space (SM) and slightly ventral to avoid penetration of the supraserratus space. The inset shows the insufflation of the subspinous space with saline solution for distention prior to portal incision. Lateral pressure is applied by the surgeon to make the medial border prominent. (B) The superior scapular portal is placed 4 cm superior to the inferior scapular portal and 2 to 3 cm medial to the medial scapular border. The portal should not be placed above the scapular spine (SP). The probe (Pr) is passed through the superior scapular portal for blunt dissection. The inset shows the insufflation of the superomedial space with saline solution for distention prior to portal incision. Lateral pressure is applied by the surgeon (H) to make the medial border prominent. (AR, arthroscope sheath; ip, inferior scapula pole; S, superior scapular portal.)
tubercle and then in forward mode for rapid bone excision. Further resection is performed using a combination of a burr and shaver blade (Fig 7). Step 6: Scapuloplasty Partial scapulectomy involves gradual and measured resection of the borders of the superomedial angle; a
Fig 3. The first anatomic landmark to be identified in the infraserratus space is the serratus anterior muscle (SRA). The probe (PR) is used to palpate the muscle and the superomedial angle (SUP), and blunt dissection is used to clear the bursa (BS). The subspinous space is inferior (INF), and the chest wall (CH) forms the floor of this space. The viewing portal is the inferior scapular portal, and the working portal is the superior scapular portal, with a 30 view.
burr is used to excise 5 to 10 mm of bone from the medial border, and resection is then extended to the superior border. The fascial attachments are visualized and preserved to prevent periscapular muscle detachment. Resection is limited to 10 mm; however, if necessary, further bone may be resected in gradual increments (Fig 8). Step 7: Final Assessment and Lavage The arthroscope is shifted to the superior scapular portal; this permits an “end-on” view of the superomedial region, and any bony spurs and sharp borders can be identified and resected (Fig 9). The superior scapular portal also permits a better view of the subspinous region, and adequacy of clearance and resection is confirmed. The debris generated from the resection can become deposited in these spaces, and thorough lavage is necessary to clear this. Postoperative chest radiographs are necessary to confirm integrity of the pleura and to rule out a pneumothorax. A bulky dressing is used for the first 2 postoperative days and is changed to a lighter portalsite dressing thereafter. Use of a sling is necessary for comfort only and is discarded in 1 to 2 days. The rehabilitation protocol involves early passive and active range-of-motion exercises (weeks 2 to 4) and simultaneous gradual strengthening of the periscapular muscles. Full range is achieved in 2 to 3 weeks, and light work is permitted. Return to heavy work and sports is permitted only after 3 months of rehabilitation.
Discussion Snapping scapula is a clinical diagnosis and is characterized by 3 key findings: (1) chronic pain and tenderness along the superomedial scapular border, (2)
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Fig 4. (A) Bursectomy is performed with a radiofrequency probe passed through the superior (S) portal cannula (Cn), and the arthroscope (Ar) is in the inferior (I) portal. A spinal needle (N) is passed in the region of the superomedial angle (SM) for orientation. (B) Superomedial space bursectomy is performed with the radiofrequency probe (RF) facing away from the chest wall (CH). The bursectomy extends from the superomedial angle (SMA) down to the subspinous bursal curtain (CT). The viewing portal is the inferior scapular portal, and the working portal is the superior scapular portal, with a 30 view. (INF, inferior; LAT, lateral; MED, medial; SC, scapula; SRA, serratus anterior; SUP, superior.)
Fig 5. (A) The second anatomic landmark is the subspinous bursal curtain (CT), and excision of this bursal thickening shows the subspinous space (asterisk). The serratus anterior (SRA) forms the roof of this space, and the chest wall (CH) is at the floor. (B) Complete excision of the bursal curtain permits visualization of the subspinous space adhesions (SSS). (C) Scapular vessels (AR) are present in the subspinous space and are seen coursing through the bursal tissue and toward the serratus anterior. The viewing portal is the inferior scapular portal, and the working portal is the superior scapular portal, with a 30 view. (in, inferior; RF, radiofrequency probe; SMA, superomedial angle; sp, superior.)
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Fig 6. (A) A rare aberrant serratus anterior superior (SRA) is seen completely covering the superomedial scapular angle (SMA). The superior 2 cm of the aberrant attachment should be excised to permit a clear view of the superomedial corner. (B) The prominent bony Luschka tubercle (TL) is exposed by excision of soft tissue superior to the serratus anterior. The superomedial scapular tip (asterisk) is the third anatomic landmark; this is located using an outside-in spinal needle (N) and demarcates the medial (M) and superior (Su) borders. The viewing portal is the inferior scapular portal, and the working portal is the superior scapular portal, with a 30 view. (b, bursa; CH, chest wall.)
periscapular crepitus that is palpable or sometimes even audible, and (3) scapular dyskinesia. MRI may show the pathologic bursa, as well as bony or muscular edema; however, its utility in the diagnostic and therapeutic algorithm has not been shown. Bony morphology can be evaluated using MRI and 3-dimensional CT scans, and real-time 4-dimensional CT scans can show additional areas of bony contact.1,11 Scapulothoracic endoscopy is effective in the treatment of snapping scapula; however, the procedure is not widely performed because of the technical
challenges and potentially dangerous complications.4-9 This report is a detailed guide to the steps of scapulothoracic endoscopy and is based on the identification of 3 anatomic landmarks (serratus anterior, subspinous bursal curtain, and superomedial bony angle). The resection area is subdivided into 3 zones (superomedial space, subspinous space, and scapular bony angle), and the procedure is described in 4 stages for optimal debridement and reproducibility. Strict adherence to these guidelines is necessary for optimal and safe surgery in this region.
Fig 7. (A) The tubercle of Luschka is seen prior to tuberoplasty. Excision of the soft tissue over the tubercle (TL) and in the superomedial space is completed with a shaver (SH), and the spinal needle (N) is used for orientation. (B) Tuberoplasty is performed with a motorized PoweRasp (PW), and the Luschka tubercle (TL) is thinned out until it is flush with the surrounding bone. The viewing portal is the inferior scapular portal, and the working portal is the superior scapular portal, with a 30 view. (CH, chest wall; SRA, serratus anterior.)
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Fig 8. (A) Measured resection for scapuloplasty involves burring the medial border (M; black arrows) and the superior edge (SU; white arrows) of the superomedial scapular angle. (B) The thinned-out tubercle (TL) is further burred to complete the resection. The fascial layer of the periscapular muscles (white arrows) is preserved and is continuous with the borders of the superomedial angle (black arrows). The viewing portal is the inferior scapular portal, and the working portal is the superior scapular portal, with a 30 view. (BR, motorized burr; TL, Luschka tubercle.)
The amount of bony resection is controversial, and the resection amount ranges between 1 and 7 cm.12,13 Bell and colleagues14-16 have described a safe zone for arthroscopic resection of the superomedial scapular border and have suggested an alternative superior portal (Bell portal) for bony resection. However, Aggarwal et al.17 have suggested that the suprascapular nerve may be vulnerable in 14% of resections, and Blønd and Rechter18 have described 1 long thoracic nerve lesion that probably occurred because of trauma from a shaver blade in the superior Bell portal. The technique described in this article and Video 1 uses only 2 portals, thereby minimizing the risk of neurovascular and muscular violation. In addition, a measured resection technique is used to quantify the amount of
Fig 9. Reversal of the portals permits visualization (CAM) of the resection area and subspinous region through the superior scapular portal (S; viewing portal). The area can be probed (PB) through the inferior portal (I; working portal). The adequacy of resection and presence of debris can be assessed. (in, inferior; LAT, lateral; N, spinal needle; Su, superior.)
Table 3. Advantages and Pitfalls of Technique Advantages The scapulothoracic endoscopy technique avoids the need for an open approach and its subsequent morbidity. Only 2 portals are required for effective and complete management. Complete bursectomy and adhesiolysis can be performed by accessing the entire pathologic infraserratus space. Newer instrumentation (PoweRasp, angled shaver blades) simplifies and optimizes the tuberoplasty and scapuloplasty procedures. The measured resection technique for scapuloplasty permits precise and systematic scapular resection. Adequate tuberoplasty decreases the bony thickness and simplifies subsequent resection. The levator scapulae attaches to the superomedial margin, and the rhomboid minor attaches to the spinous region of the medial scapular border. The measured resection technique limits the resection to 5-10 mm; fascial attachments to the scapular angle are thereby preserved, and this maintains continuity of the important periscapular muscles. The step-by-step approach simplifies the procedure and shortens the learning curve for the technique. Pitfalls Precise portal placement is crucial. Incorrect angulation can result in intrathoracic penetration of the sheath. Alternately, the sheath may enter the supraserratus space between the subscapularis and serratus anterior, with potentially dangerous neurovascular complications. The dorsal scapular and spinal accessory nerves are close to the medial scapular border. Incorrect portal placement may damage these important nerves. The apical pleura is in proximity to the superomedial angle. Damage to the pleura during bursectomy can lead to a pneumothorax. Meticulous intraoperative monitoring should be routinely performed and a chest radiograph should be routinely obtained at the end of the procedure to rule out pneumothorax. Scapular arteries are present and can be identified in the subspinous space. Damage to these vessels can lead to torrential hemorrhage, and the procedure may have to be abandoned. Excessive resection can result in detachment of the levator scapulae and rhomboid minor muscles and can worsen the snapping and scapular dyskinesia in the postoperative period. Inadequate debridement will result in persistence or recurrence of the painful snapping, as well as inadequate symptomatic relief.
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bone resected. In my experience, the 2-portal technique provides an optimal viewing angle, and a third portal for resection is avoided by using new instrumentation such as the PoweRasp. The overall advantages and pitfalls of the procedure are summarized in Table 3.
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8. Ruland LJ III, Ruland CM, Matthews LS. Scapulothoracic anatomy for the arthroscopist. Arthroscopy 1995;11:52-56. 9. Wascher DC, Aboka A, Menzer H. Safety of portal placement for scapulothoracic arthroscopy. Arthroscopy 2011;27:e93-e94. 10. Boyle MJ, Misur P, Youn SM, Ball CM. The superomedial bare area of the costal scapula surface: A possible cause of snapping scapula syndrome. Surg Radiol Anat 2013;35:9598. 11. Bell SN, Troupis JM, Miller D, Alta TD, Coghlan JA, Wijeratna MD. Four-dimensional computed tomography scans facilitate preoperative planning in snapping scapula syndrome. J Shoulder Elbow Surg 2015;24:e83-e90. 12. Lehtinen JT, Macy JC, Cassinelli E, Warner JJ. The painful scapulothoracic articulation: Surgical management. Clin Orthop Relat Res 2004:99-105. 13. Oizumi N, Suenaga N, Minami A. Snapping scapula caused by abnormal angulation of the superior angle of the scapula. J Shoulder Elbow Surg 2004;13:115-118. 14. 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;17:647-649. 15. Chan BK, Chakrabarti AJ, Bell SN. An alternative portal for scapulothoracic arthroscopy. J Shoulder Elbow Surg 2002;11:235-238. 16. Pavlik A, Ang K, Coghlan J, Bell S. Arthroscopic treatment of painful snapping of the scapula by using a new superior portal. Arthroscopy 2003;19:608-612. 17. Aggarwal A, Wahee P, Aggarwal AK, Kaur H, Sahni D. Anatomical considerations for safe scapular resection in snapping scapula syndrome. Surg Radiol Anat 2012;34:43-47. 18. Blønd L, Rechter S. Arthroscopic treatment for snapping scapula: A prospective case series. Eur J Orthop Surg Traumatol 2014;24:159-164.