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An alternative portal for scapulothoracic arthroscopy
An alternative portal for scapulothoracic arthroscopy Beng-Kuen Chan, FRCS,a Anil J. Chakrabarti, FRCS(Orth),b and Simon N. Bell, FRACS,c Singapore, Norfolk, United Kingdom, and Melbourne, Australia
Access to the superior angle of the scapula during scapulothoracic arthroscopy with current standard portals can be difficult. A safe, effective alternative portal for scapulothoracic arthroscopy, located superior to the scapula, is described, which enables easier resection of the superomedial angle for treatment of the snapping scapula. (J Shoulder Elbow Surg 2002;11: 235-8.)
INTRODUCTION Snapping scapula is a clinical condition of audible grating at the superomedial angle of the scapula with associated pain, particularly with overhead activities. The possible causes have been comprehensively described by Harper et al.4 Conservative treatment entails adequate explanation and physiotherapy and, in many cases, is successful. In those patients with unacceptable continuing symptoms, removal of a portion of the superior angle of the scapula has been shown to be effective. This treatment was initially described as an open procedure,5 but Harper et al4 recently described successful removal of adequate bone arthroscopically. Arthroscopy portals for scapulothoracic arthroscopy situated along the medial border at, and inferior to, the level of the scapula spine have been described.4,6 However, the depth of penetration required through the rhomboid muscles, together with the close proximity of the viewing and working cannulae, often makes access to the superomedial angle of the scapula difficult. The aim of this study was to find an alternative portal for scapulothoracic arthroscopy to make resection of the superomedial angle easier but safe. From the Department of Orthopaedic Surgery, Changi General Hospital, Singapore,a Queen Elizabeth Hospital, King’s Lynn, Norfolk, United Kingdom,b and the Monash University Department of Surgery, Monash Medical Centre, Melbourne, Australia.c Reprint requests: Mr Simon N. Bell, Melbourne Shoulder and Elbow Centre, 31 Normanby St, Brighton 3186, Victoria, Australia. Copyright © 2002 by Journal of Shoulder and Elbow Surgery Board of Trustees. 1058-2746/2002/$35.00 ⫹ 0 32/1/121767 doi:10.1067/mse.2002.121767
Figure 1 The left scapular region as viewed posteriorly, demonstrating the “inside out” technique of creating the superior portal.
METHOD From studies of the anatomy of the scapulothoracic region, it was postulated that there is a potential, safe, superiorly located portal for scapulothoracic arthroscopy that should improve access to the superior angle of the scapula. We believed that it would be safest to create this portal with an “inside out” technique from an initial, recognized medial portal.4,6 A line was marked between the superior angle of the scapula medially and the outer aspect of the acromion laterally and divided into thirds. These 2 points were chosen because they are easily palpable fixed bony landmarks. The point of entry of the arthroscopic trocar was from the safe portal (2 cm medial to the medial border of the scapula just below the level of the spine of the scapula). The point of exit for the trocar was the junction of the medial and middle thirds of the marked imaginary line; this forms the proposed superior portal (Figure 1). The instrument was directed toward this point, staying close to the ventral surface of the scapula. Nine preserved cadaveric specimens of the complete shoulder girdle were dissected, after introduction of an arthroscopic trocar through the proposed portal at the superior edge of the scapula. Dissection was carried out
235
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Chan, Chakrabarti, and Bell
J Shoulder Elbow Surg May/June 2002
Figure 2 The left scapular region as viewed posteriorly. The trapezius muscle has been reflected medially from its attachment along the spine of the scapula to demonstrate the accessory nerve running on the deep surface of the muscle. Note the passage of the Steinmann pin through the proposed superiorly sited portal.
through the scalenus medius muscle, was also identified. Its course was traced as it passed deep to the levator scapulae. The supraspinatus muscle was then lifted off of its fossa to expose the suprascapular nerve at the suprascapular notch. With the use of pointed dividers, the closest distance, in millimeters, from the arthroscopic portal to the 3 nerves was recorded. This study was repeated with 5 fresh cadaveric shoulders, with the cadavers placed in a lateral position to simulate actual operative positioning.
RESULTS Figures 2 and 3 demonstrate the relationship of the proposed portal to the major nerves in the area, and Tables I and II show the distance (in millimeters) between each nerve and the arthroscopic portal in preserved and fresh cadavers, respectively. Clinical cases
Figure 3 The left scapular region as viewed posteriorly. The relationship of the superior portal to the major nerves in the area is demonstrated.
to determine the distance between the neural structures around the shoulder joint and the arthroscopic portal. The course of the structures in question was also documented. The dissection started with removal of all skin and subcutaneous tissue. Access to the posterior triangle of the neck and isolation of the spinal accessory nerve were achieved after reflection of the trapezius muscle from the spine of the scapula and the clavicle (Figure 2). The dorsal scapular nerve, where it exits behind or
On the basis of the findings of this study, 9 patients with snapping scapulae had arthroscopic removal of the superomedial corner of the scapula by means of the superior portal (Figure 4). Visualization and resection of the superomedial angle of the scapula seemed technically easier through use of the additional superior portal. Postoperatively, none of the patients had evidence of neurologic injury. DISCUSSION Ciullo2 introduced the concept of arthroscopic debridement of the scapulothoracic joint but without precise details of the arthroscopic technique. The accepted method of positioning the arm is with the shoulder in extension and internal rotation (“chicken
Chan, Chakrabarti, and Bell
J Shoulder Elbow Surg Volume 11, Number 3
237
Figure 4 Arthroscopic debridement of the superomedial angle of the left scapula. The patient is in a lateral position with the left arm in traction. The arthroscope is introduced via the proposed superiorly sited portal.
wing position”), and the recommended position of the patient is prone.4 However, concurrent arthroscopic assessment of the glenohumeral joint in this position is difficult. For this reason, we prefer to place the patient in a conventional full lateral position. Glenohumeral assessment is made arthroscopically with the arm in traction. A sterile stockinet is subsequently applied and the arm brought into the “chicken wing position” to proceed with scapulothoracic arthroscopy. The regional anatomy with respect to portal placement has been described by Ruland et al.6 They describe safe access to the scapulothoracic articulation by recommending that the portals be located inferior to the scapula spine and 3 to 4 fingerbreadths from the vertebral border of the scapula. However, the close proximity of the viewing and working cannulae, as well as the depth of penetration required through the rhomboid muscles, makes access to the superior pole difficult. The technical advantages of finding an equally safe portal at the superior aspect of the articulation are evident. It has been suggested that a portal in close proximity to the superior angle of the scapula would put neurovascular structures, including the accessory nerve, the suprascapular nerve, and the dorsal scapular nerve, at risk. The anatomic relationships of the accessory nerve in the posterior triangle of the neck are well described, but its distal course is less clearly defined. Ruland et al6 have described its course through the mid section of levator scapulae as the nerve travels deep to the trapezius. With respect to our proposed arthroscopic portal, the mean distance to the accessory nerve beneath the trapezius was 35 mm. The suprascapular nerve has been studied in detail in relation to transglenoid arthroscopic drill placement
Table I Distance (in millimeters) between each nerve and arthroscopic portal in preserved cadavers Cadaver No. (preserved)
Accessory nerve
Dorsal scapular nerve
1 2 3 4 5 6 7 8 9 Mean (SD)
20 53 28 48 40 37 56 21 16 35.4 (14.9)
31 45 32 41 39 25 31 — 33 34.6 (6.5)
Suprascapular nerve 22 23 22 23 25 22 25 12 18 21.3 (4.1)
Table II Distance (in millimeters) between each nerve and arthroscopic portal in fresh-frozen cadavers Cadaver No. (fresh frozen)
Accessory nerve
Dorsal scapular nerve
1 2 3 4 5 Mean (SD)
21 17 18 16 19 18.2 (1.9)
22 19 24 19 17 20.2 (2.8)
Suprascapular nerve 25 24 28 22 24 24.6 (2.2)
and other nonarthroscopic surgical procedures.1 Such detailed study of its anatomic relationships proximal to the suprascapular notch has not been done. In our 9 specimens, the suprascapular nerve maintained a constant course with respect to the scapula and
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passed obliquely away from the arthroscopic portal toward the suprascapular notch. Its distance from the portal was, on average, 21 mm. The course of the dorsal scapular nerve has been well described by Frank et al.3 The nerve pierces the scalenus medius muscle and travels deep to or through the levator scapulae on its way to supply the rhomboids roughly parallel to the medial border of the scapula. From our dissection, we found that the nerve was, on average, 35 mm away from the proposed portal. On comparing the results of the dissection in both preserved and fresh cadavers, we found similar results. The distances between the portals and the nerves seemed to be smaller in the fresh cadavers. This can be explained by the fact that the preserved cadavers were white patients and the fresh cadavers were all Asian patients with smaller body build. Nevertheless, the results of the dissection in both groups show that a safe margin is present with this portal. The findings of this anatomic study indicate that a safe superior portal exists. It has been used by several surgeons without any neurologic injury. Scapulothoracic arthroscopy, however, remains technically de-
J Shoulder Elbow Surg May/June 2002
manding and should only be attempted by an experienced arthroscopist. The bony landmarks should be drawn out preoperatively and a needle placed at the superomedial corner of the scapula to aid instrument placement. Care must be taken not to penetrate the thoracic cavity when creating the medial portals. We have found that visualization and resection of the superior angle of the scapula are technically easier using an additional superior portal. REFERENCES
1. Bigliani LU, Dalsey RM, McCann PD, April EW. An anatomical study of the suprascapular nerve. Arthroscopy 1990;6:301-5. 2. Ciullo JV. Subscapular bursitis. Treatment of “snapping scapula” or “washboard syndrome.” Arthroscopy 1992;8:412-3. 3. Frank DK, Wenk E, Stern JC, Gottlieb RD, Moscatello AL. A cadaveric study of the motor nerves to the levator scapulae muscle. Otolaryngol Head Neck Surg 1997;117:671-80. 4. Harper GD, McIlory S, Bayley JIL, Calvert PT. Arthroscopic partial resection of the scapula for snapping scapula: a new technique. J Shoulder Elbow Surg 1999;8:53-7. 5. Milch H. Partial scapulectomy for snapping of the scapula. J Bone Joint Surg Am 1950;32:561-6. 6. Ruland LJ, Ruland CM, Matthews LS. Scapulothoracic anatomy for the arthroscopist. Arthroscopy 1995;11:52-6.
RECEIVE THE JOURNAL’S TABLE OF CONTENTS EACH MONTH BY E-MAIL To receive the tables of contents by e-mail, sign up through our Web site at http://www.mosby.com/jshoulder Choose E-mail notification. Simply type your e-mail address in the box and clock the Subscribe button. Alternatively, you may send an e-mail message to [email protected]. Leave the subject line blank, and type the following as the body of your message: subscribe s&e_toc You will receive an e-mail message confirming that you have been added to the mailing list. Note that table of contents e-mail messages will be sent when a new issue is posted to the Web site.
Access to the superior angle of the scapula during scapulothoracic arthroscopy with current standard portals can be difficult. A safe, effective alternative portal for scapulothoracic arthroscopy, located superior to the scapula, is described, which enables easier resection of the superomedial angle for treatment of the snapping scapula. (J Shoulder Elbow Surg 2002;11: 235-8.)
INTRODUCTION Snapping scapula is a clinical condition of audible grating at the superomedial angle of the scapula with associated pain, particularly with overhead activities. The possible causes have been comprehensively described by Harper et al.4 Conservative treatment entails adequate explanation and physiotherapy and, in many cases, is successful. In those patients with unacceptable continuing symptoms, removal of a portion of the superior angle of the scapula has been shown to be effective. This treatment was initially described as an open procedure,5 but Harper et al4 recently described successful removal of adequate bone arthroscopically. Arthroscopy portals for scapulothoracic arthroscopy situated along the medial border at, and inferior to, the level of the scapula spine have been described.4,6 However, the depth of penetration required through the rhomboid muscles, together with the close proximity of the viewing and working cannulae, often makes access to the superomedial angle of the scapula difficult. The aim of this study was to find an alternative portal for scapulothoracic arthroscopy to make resection of the superomedial angle easier but safe. From the Department of Orthopaedic Surgery, Changi General Hospital, Singapore,a Queen Elizabeth Hospital, King’s Lynn, Norfolk, United Kingdom,b and the Monash University Department of Surgery, Monash Medical Centre, Melbourne, Australia.c Reprint requests: Mr Simon N. Bell, Melbourne Shoulder and Elbow Centre, 31 Normanby St, Brighton 3186, Victoria, Australia. Copyright © 2002 by Journal of Shoulder and Elbow Surgery Board of Trustees. 1058-2746/2002/$35.00 ⫹ 0 32/1/121767 doi:10.1067/mse.2002.121767
Figure 1 The left scapular region as viewed posteriorly, demonstrating the “inside out” technique of creating the superior portal.
METHOD From studies of the anatomy of the scapulothoracic region, it was postulated that there is a potential, safe, superiorly located portal for scapulothoracic arthroscopy that should improve access to the superior angle of the scapula. We believed that it would be safest to create this portal with an “inside out” technique from an initial, recognized medial portal.4,6 A line was marked between the superior angle of the scapula medially and the outer aspect of the acromion laterally and divided into thirds. These 2 points were chosen because they are easily palpable fixed bony landmarks. The point of entry of the arthroscopic trocar was from the safe portal (2 cm medial to the medial border of the scapula just below the level of the spine of the scapula). The point of exit for the trocar was the junction of the medial and middle thirds of the marked imaginary line; this forms the proposed superior portal (Figure 1). The instrument was directed toward this point, staying close to the ventral surface of the scapula. Nine preserved cadaveric specimens of the complete shoulder girdle were dissected, after introduction of an arthroscopic trocar through the proposed portal at the superior edge of the scapula. Dissection was carried out
235
236
Chan, Chakrabarti, and Bell
J Shoulder Elbow Surg May/June 2002
Figure 2 The left scapular region as viewed posteriorly. The trapezius muscle has been reflected medially from its attachment along the spine of the scapula to demonstrate the accessory nerve running on the deep surface of the muscle. Note the passage of the Steinmann pin through the proposed superiorly sited portal.
through the scalenus medius muscle, was also identified. Its course was traced as it passed deep to the levator scapulae. The supraspinatus muscle was then lifted off of its fossa to expose the suprascapular nerve at the suprascapular notch. With the use of pointed dividers, the closest distance, in millimeters, from the arthroscopic portal to the 3 nerves was recorded. This study was repeated with 5 fresh cadaveric shoulders, with the cadavers placed in a lateral position to simulate actual operative positioning.
RESULTS Figures 2 and 3 demonstrate the relationship of the proposed portal to the major nerves in the area, and Tables I and II show the distance (in millimeters) between each nerve and the arthroscopic portal in preserved and fresh cadavers, respectively. Clinical cases
Figure 3 The left scapular region as viewed posteriorly. The relationship of the superior portal to the major nerves in the area is demonstrated.
to determine the distance between the neural structures around the shoulder joint and the arthroscopic portal. The course of the structures in question was also documented. The dissection started with removal of all skin and subcutaneous tissue. Access to the posterior triangle of the neck and isolation of the spinal accessory nerve were achieved after reflection of the trapezius muscle from the spine of the scapula and the clavicle (Figure 2). The dorsal scapular nerve, where it exits behind or
On the basis of the findings of this study, 9 patients with snapping scapulae had arthroscopic removal of the superomedial corner of the scapula by means of the superior portal (Figure 4). Visualization and resection of the superomedial angle of the scapula seemed technically easier through use of the additional superior portal. Postoperatively, none of the patients had evidence of neurologic injury. DISCUSSION Ciullo2 introduced the concept of arthroscopic debridement of the scapulothoracic joint but without precise details of the arthroscopic technique. The accepted method of positioning the arm is with the shoulder in extension and internal rotation (“chicken
Chan, Chakrabarti, and Bell
J Shoulder Elbow Surg Volume 11, Number 3
237
Figure 4 Arthroscopic debridement of the superomedial angle of the left scapula. The patient is in a lateral position with the left arm in traction. The arthroscope is introduced via the proposed superiorly sited portal.
wing position”), and the recommended position of the patient is prone.4 However, concurrent arthroscopic assessment of the glenohumeral joint in this position is difficult. For this reason, we prefer to place the patient in a conventional full lateral position. Glenohumeral assessment is made arthroscopically with the arm in traction. A sterile stockinet is subsequently applied and the arm brought into the “chicken wing position” to proceed with scapulothoracic arthroscopy. The regional anatomy with respect to portal placement has been described by Ruland et al.6 They describe safe access to the scapulothoracic articulation by recommending that the portals be located inferior to the scapula spine and 3 to 4 fingerbreadths from the vertebral border of the scapula. However, the close proximity of the viewing and working cannulae, as well as the depth of penetration required through the rhomboid muscles, makes access to the superior pole difficult. The technical advantages of finding an equally safe portal at the superior aspect of the articulation are evident. It has been suggested that a portal in close proximity to the superior angle of the scapula would put neurovascular structures, including the accessory nerve, the suprascapular nerve, and the dorsal scapular nerve, at risk. The anatomic relationships of the accessory nerve in the posterior triangle of the neck are well described, but its distal course is less clearly defined. Ruland et al6 have described its course through the mid section of levator scapulae as the nerve travels deep to the trapezius. With respect to our proposed arthroscopic portal, the mean distance to the accessory nerve beneath the trapezius was 35 mm. The suprascapular nerve has been studied in detail in relation to transglenoid arthroscopic drill placement
Table I Distance (in millimeters) between each nerve and arthroscopic portal in preserved cadavers Cadaver No. (preserved)
Accessory nerve
Dorsal scapular nerve
1 2 3 4 5 6 7 8 9 Mean (SD)
20 53 28 48 40 37 56 21 16 35.4 (14.9)
31 45 32 41 39 25 31 — 33 34.6 (6.5)
Suprascapular nerve 22 23 22 23 25 22 25 12 18 21.3 (4.1)
Table II Distance (in millimeters) between each nerve and arthroscopic portal in fresh-frozen cadavers Cadaver No. (fresh frozen)
Accessory nerve
Dorsal scapular nerve
1 2 3 4 5 Mean (SD)
21 17 18 16 19 18.2 (1.9)
22 19 24 19 17 20.2 (2.8)
Suprascapular nerve 25 24 28 22 24 24.6 (2.2)
and other nonarthroscopic surgical procedures.1 Such detailed study of its anatomic relationships proximal to the suprascapular notch has not been done. In our 9 specimens, the suprascapular nerve maintained a constant course with respect to the scapula and
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Chan, Chakrabarti, and Bell
passed obliquely away from the arthroscopic portal toward the suprascapular notch. Its distance from the portal was, on average, 21 mm. The course of the dorsal scapular nerve has been well described by Frank et al.3 The nerve pierces the scalenus medius muscle and travels deep to or through the levator scapulae on its way to supply the rhomboids roughly parallel to the medial border of the scapula. From our dissection, we found that the nerve was, on average, 35 mm away from the proposed portal. On comparing the results of the dissection in both preserved and fresh cadavers, we found similar results. The distances between the portals and the nerves seemed to be smaller in the fresh cadavers. This can be explained by the fact that the preserved cadavers were white patients and the fresh cadavers were all Asian patients with smaller body build. Nevertheless, the results of the dissection in both groups show that a safe margin is present with this portal. The findings of this anatomic study indicate that a safe superior portal exists. It has been used by several surgeons without any neurologic injury. Scapulothoracic arthroscopy, however, remains technically de-
J Shoulder Elbow Surg May/June 2002
manding and should only be attempted by an experienced arthroscopist. The bony landmarks should be drawn out preoperatively and a needle placed at the superomedial corner of the scapula to aid instrument placement. Care must be taken not to penetrate the thoracic cavity when creating the medial portals. We have found that visualization and resection of the superior angle of the scapula are technically easier using an additional superior portal. REFERENCES
1. Bigliani LU, Dalsey RM, McCann PD, April EW. An anatomical study of the suprascapular nerve. Arthroscopy 1990;6:301-5. 2. Ciullo JV. Subscapular bursitis. Treatment of “snapping scapula” or “washboard syndrome.” Arthroscopy 1992;8:412-3. 3. Frank DK, Wenk E, Stern JC, Gottlieb RD, Moscatello AL. A cadaveric study of the motor nerves to the levator scapulae muscle. Otolaryngol Head Neck Surg 1997;117:671-80. 4. Harper GD, McIlory S, Bayley JIL, Calvert PT. Arthroscopic partial resection of the scapula for snapping scapula: a new technique. J Shoulder Elbow Surg 1999;8:53-7. 5. Milch H. Partial scapulectomy for snapping of the scapula. J Bone Joint Surg Am 1950;32:561-6. 6. Ruland LJ, Ruland CM, Matthews LS. Scapulothoracic anatomy for the arthroscopist. Arthroscopy 1995;11:52-6.
RECEIVE THE JOURNAL’S TABLE OF CONTENTS EACH MONTH BY E-MAIL To receive the tables of contents by e-mail, sign up through our Web site at http://www.mosby.com/jshoulder Choose E-mail notification. Simply type your e-mail address in the box and clock the Subscribe button. Alternatively, you may send an e-mail message to [email protected]. Leave the subject line blank, and type the following as the body of your message: subscribe s&e_toc You will receive an e-mail message confirming that you have been added to the mailing list. Note that table of contents e-mail messages will be sent when a new issue is posted to the Web site.