MR measurements of subcoracoid impingement using a new method and its relationship to rotator cuff pathology at MR arthrography

Transcription

1 MR measurements of subcoracoid impingement using a new method and its relationship to rotator cuff pathology at MR arthrography Poster No.: P-0055 Congress: ESSR 2014 Type: Authors: Keywords: DOI: Scientific Poster N. Porter, J. Singh, B. Tins, R. K. Lalam, P. Tyrrell, V. Cassar- Pullicino; Oswestry/UK Musculoskeletal joint, MR, Arthrography, Arthritides /essr2014/P-0055 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 11

2 Purpose Subcoracoid impingement is a recognised cause of anterior shoulder pain Traditional measurement uses axial coracohumeral interval to determine the degree of subcoracoid stenosis and impingement Recent surgical studies have shown that the shape of the subcoracoid outlet may be more important [1-4]. In particular, a low lying coracoid tip, giving rise to a "chevron" shaped outlet, has been shown to be more associated with subcoracoid impingement (Figure 1). Coracohumeral distance has also been shown to be a poor predictor of subcoracoid impingement on MR [5] Our purpose was to determine whether a vertical measurement on MR reflecting the distance of the coracoid tip below the supraglenoid tubercle would have more bearing on rotator cuff pathology compared with the axial coracohumeral distance Images for this section: Page 2 of 11

3 Fig. 1: Sagittal diagrams showing how the distance that the coracoid tip (arrows) lies below the supraglenoid tubercle (arrow heads) can change the shape of the inlet (shaded area). In diagram A, the coracoid tip is low lying, resulting in a "chevron" shaped inlet. This causes severe reduction in subcoracoid space when compared with diagram B in which there is a more superiorly positioned coracoid tip. Page 3 of 11

4 Methods and Materials 100 consecutive MR arthrograms over a 6 month period were retrospectively reviewed independently by two radiologists Any discrepancies were reviewed by a third radiologist 2 steps to the assessment: Step 1. Each assessor commented on the degree of tendinopathy or tears of suscapularis, supraspinatus and long head of biceps. A grading system was used, based on a modification of the technique described by Pfirrmann et al [6]. Grade 0 = normal tendon; Grade 1 = tendinopathy (consisting of 2 of the following: signal change, morphological change, swelling) or partial tear less than 25% diameter; Grade 2 = partial tear more than 25% diameter; Grade 3 = complete detachment of tendon. Step 2. On a separate occasion each assessor measured the vertical distance of the coracoid tip below the supraglenoid tubercle as well as the axial coracohumeral distance. The vertical distance was measured using sagittal oblique sequences. First the location of the coracoid tip was identified on the sagittal oblique sequence. Without moving the cursor, the images were scrolled through to the slice showing the supraglenoid tubercle, the position of which was confirmed by the attachment site of the long head of biceps tendon. An arrow was drawn on this image representing the location of the coracoid tip. The vertical distance from the arrow representing the location of the coracoid tip to the level of the supraglenoid tubercle was then measured as detailed in figure 2. If the supraglenoid tubercle was located below the coracoid tip then this was recorded as a negative number. Statistical difference regarding each of these measurements in patients with tendinopathy compared to those without tendinopathy was performed using Student's T-test. Images for this section: Page 4 of 11

5 Fig. 2: Sagittal oblique T1 fat saturation image demonstrating measurement of vertical distance of the coracoid tip below the supraglenoid tubercle. Initially the cursor was placed over the coracoid tip. Without moving the cursor, the images were scrolled through to the level of the glenoid. An arrow was then drawn on this image to depict the level of the coracoid tip. A line was then drawn inferiorly from the supraglenoid tubercle, bisecting the labrum (line a). A second line (line b) was then drawn perpendicular to line a, intersecting it at the level of the supraglenoid tubercle. Finally a third line (line c) was drawn parallel to line a, from the arrow depicting the level of the coracoid tip to line b (the level of the supraglenoid tubercle). This distance (line c) represents the vertical distance that the coracoid tip lies below the supraglenoid tubercle. Page 5 of 11

6 Results Of the 100 MR arthrograms: 42 had subscapularis tendinopathy 21 had long head of biceps tendinopathy 53 had supraspinatus tendinopathy Only 2 cases had a discrepancy between the two assessors, requiring input of the 3rd assessor Mean age was 39 years, median 40 years, range 13 years to 76 years 74 males, 26 females 70 right shoulder, 30 left shoulder Mean vertical distance from coracoid tip to supraglenoid tubercle = 6.6mm Mean axial coracohumeral distance = 12.2mm For supraspinatus tendinopathy (Figure 3) the mean vertical distance with tendinopathy was 7.3mm, compared to 5.8mm in those without (P=0.005). Mean axial coracohumeral distance was 11.8mm for those with supraspinatus tendinopathy, compared to 12.6mm for those without (P=0.059) Mean vertical distance in patients with subscapularis tendinopathy (Figure 4) was 7.3mm, compared to 6.1mm in those without (P=0.109). Mean axial coracohumeral disatance was 11.8mm in cases with subscapularis tendinopathy, compared to 12.5mm in those without (P=0.331) Mean vertical distance for those with long head of biceps tendinopathy (Figure 5) was 6.5mm, compared to 6.6mm for those without (P=0.945). For those with long head of biceps tendinopathy the mean axial coracohumeral distance was 11.6mm, compared to 12.4mm for those without (P=0.282) Images for this section: Page 6 of 11

7 Fig. 3: Supraspinatus tendinopathy (arrow) in a patient with a low lying coracoid tip. Page 7 of 11

8 Fig. 4: Subscapularis tendinopathy in a patient with a low lying coracoid tip and reduced subcoracoid space. This case also demonstrates the "roller-wringer" effect (arrow), in which the deep fibres of subscapularis are predominantly involved in impingement. Page 8 of 11

9 Fig. 5: Long head of biceps tendinopathy (arrow) in a patient with a low lying coracoid tip and reduced subacromial space. Page 9 of 11

10 Conclusion Our results show that the vertical distance that the coracoid tip lies below the supraglenoid tubercle was greater in those with supraspinatus or subcapularis tendinopathy, compared to those without Greater statistical correlation for tendinopathy with the vertical measurement than compared with the traditional axial coracohumeral distance Our findings support surgical studies suggesting the shape of the inlet is more important in determining pathology Highly statistically significant difference for the supraspinatus group. This suggests that the position of the coracoid tip has an influence not just on subcoracoid impingement, but effects the shape of the entire rotator cuff outlet The presence of a low lying coracoid tip should therefore be highlighted in reporting shoulder MR as this may relate to the development of rotator cuff tendinopathy and greatly influence patient management References 1. Okoro T, Reddy VR, Pimpelnarkar A. Coracoid impingement syndrome: A literature review. Curr Rev Musculoskeletal Med 2009; 2: Kragh JF, Doukas WC, Basamania CJ. Primary coracoid impingement syndrome. Am J Orthop 2004; 33: Freehill MQ. Coracoid impingement: Diagnosis and treatment. J Am Acad Orthop Surg 2011; 19: Lo IK, Burkhart SS. The etiology and assessment of subscapularis tendon tears: a case for subcoracoid impingement, the roller-wringer effect, and TUFF lesions of the subscapularis. Arthroscopy 2003; 19: Giaroli EL, Major NM, Lemley DE, Lee J. Coracohumeral interval imaging in subcoracoid impingement syndrom on MRI. Am J Roentgenol 2006; 186: Pfirrmann CWA, Zanetti M, Weishaupt D, Gerber C, Hodler J. Subscapularis tendon tears: detection and grading at MR arthrography. Radiology 1999; 213: Page 10 of 11

11 Personal Information The study was approved by the local research and development review board. Page 11 of 11