Downloaded from ard.bmj.com on September 26, 2014 - Published by group.bmj.com
Letter
Paying attention to carpal tunnel contents lesions: ultrasound for evaluation of carpal tunnel syndrome We read with great interest the report by Dejaco et al1 related to diagnosis of carpal tunnel syndrome (CTS) by ultrasound. Dejaco et al compared ultrasound measurement of median nerve cross-sectional area (CSA) at different anatomical landmarks in great detail and evaluated the value of intranerval power Doppler signals for CTS diagnosis. It provided a good data support for the ultrasonic evaluation of CTS. However, this study prompts questions on the three following points: 1. CSA as an important indicator for CTS diagnosis also has limitations. We do agree that CSA is the most commonly used for evaluation of nerve swelling. However, some patients had typical clinical symptoms, but those median nerves did not necessarily present obviously swelling and compression at the carpal tunnel inlet or outlet. Instead, the ultrasonography showed the abnormal echo of contents within carpal tunnel. Several reports also have been published on CTS caused by space-occupying lesions, including tenosynovitis,2–4 tumours,2 4 5 calcified mass4 6 or tophaceous gout.4 7 We also found such cases were common in systemic diseases such as rheumatoid arthritis, diabetes mellitus, gout and so on. Take tenosynovitis for example, transverse sonography of the median nerve at the level of the pisiform bone showed an ovoid hypoechoic reticular structure without swelling. However, the deep tissue of nerve showed hypoechoic swelling (figure 1A). On the longitudinal sonograms, the nerve appeared as a consistent thickness of strip structure without a sudden thinning or thickening (figure1B). However, power Doppler showed increased blood flow signal within the nerve and carpal tunnel (figure1B, C). CSA as a diagnostic criterion will increase the false-negative rate of CTS. 2. Ultrasound also has disadvantages for diagnosis of CTS. As we know, the diagnosis of CTS is based primarily on clinical examination and nerve conduction studies. In the last 20 years, ultrasound has been employed as an important imaging tool for CTS. The value of sonographic assessment for CTS depended mainly on three sonographic techniques: measurement of median nerve CSA at differential locations along the carpal tunnel, structural analysis of the median nerve and bowing of the flexor retinaculum.8 We agree ultrasound can evaluate morphological changes of median nerve and provide a good data support for CTS. More specifically,
ultrasound is not much an evaluation as a diagnostic tool for CTS. The term ‘volume’ mentioned in the title was used inappropriately. The volume of median nerve should be measured on the 3D space image. However, Dejaco et al1 measured CSA of nerves on the 2D image. In order to avoid ambiguity, we proposed to use the term ‘area’. Jiaan zhu, Fang Liu Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai Institute of Ultrasound in Medicine, Shanghai, China Correspondence to Professor Jiaan zhu, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai Institute of Ultrasound in Medicine, 600 Yishan Road, Shanghai, China; [email protected] Contributors Jz: concept, writing; FL: writing. Competing interests None. Provenance and peer review Not commissioned; internally peer reviewed. To cite zhu J, Liu F. Ann Rheum Dis 2014;73:e16. Received 4 December 2013 Accepted 8 December 2013 Published Online First 20 December 2013
▸ http://dx.doi.org/10.1136/annrheumdis-2013-205038 Ann Rheum Dis 2014;73:e16. doi:10.1136/annrheumdis-2013-205015
REFERENCES 1
2 3 4 5 6 7 8
Dejaco C, Stradner M, Zauner D, et al. Ultrasound for diagnosis of carpal tunnel syndrome: comparison of different methods to determine median nerve volume and value of power Doppler sonography. Ann Rheum Dis 2013;72:1934–9. Chen CH, Wu T, Sun JS, et al. Unusual causes of carpal tunnel syndrome: space occupying lesions. J Hand Surg Eur Vol 2012;37:14–9. Klauser AS, Faschingbauer R, Bauer T, et al. Entrapment neuropathies II: carpal tunnel syndrome. Semin Musculoskelet Radiol 2010;14:487–500. Kang HJ, Jung SH, Yoon HK, et al. Carpal tunnel syndrome caused by space occupying lesions. Yonsei Med J 2009;50:257–61. Ait Essi F, Younsi A, Abkari I, et al. Diffuse tenosenovial giant cell tumor of the wrist revealed by carpal tunnel syndrome: report of a case. Chir Main 2012;31:256–8. Takada T, Fujioka H, Mizuno K. Carpal tunnel syndrome caused by an idiopathic calcified mass. Arch Orthop Trauma Surg 2000;120:226–7. Patil VS, Chopra A. Watch out for ‘pins and needles’ in hands--it may be a case of gout. Clin Rheumatol 2007;26:2185–7. Nakamichi K, Tachibana S. Ultrasonographic findings in isolated neuritis of the posterior interosseous nerve: comparison with normal findings. J Ultrasound Med 2007;26:683–7.
Figure 1 Transverse and longitudinal sonograms of the median nerve at the carpal tunnel. (A) Transverse sonogram of the median nerve at the level of the pisiform bone (cross-sectional area: 7 mm2). (B) Longitudinal sonogram of the median nerve. (C) Transverse sonogram of the carpal tunnel with abundant blood flow signal.
Ann Rheum Dis April 2014 Vol 73 No 4
e16
Downloaded from ard.bmj.com on September 26, 2014 - Published by group.bmj.com
Paying attention to carpal tunnel contents lesions: ultrasound for evaluation of carpal tunnel syndrome Jiaan zhu and Fang Liu Ann Rheum Dis 2014 73: e16 originally published online December 20, 2013
doi: 10.1136/annrheumdis-2013-205015
Updated information and services can be found at: http://ard.bmj.com/content/73/4/e16.full.html
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References
This article cites 8 articles, 3 of which can be accessed free at: http://ard.bmj.com/content/73/4/e16.full.html#ref-list-1
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Letter
Paying attention to carpal tunnel contents lesions: ultrasound for evaluation of carpal tunnel syndrome We read with great interest the report by Dejaco et al1 related to diagnosis of carpal tunnel syndrome (CTS) by ultrasound. Dejaco et al compared ultrasound measurement of median nerve cross-sectional area (CSA) at different anatomical landmarks in great detail and evaluated the value of intranerval power Doppler signals for CTS diagnosis. It provided a good data support for the ultrasonic evaluation of CTS. However, this study prompts questions on the three following points: 1. CSA as an important indicator for CTS diagnosis also has limitations. We do agree that CSA is the most commonly used for evaluation of nerve swelling. However, some patients had typical clinical symptoms, but those median nerves did not necessarily present obviously swelling and compression at the carpal tunnel inlet or outlet. Instead, the ultrasonography showed the abnormal echo of contents within carpal tunnel. Several reports also have been published on CTS caused by space-occupying lesions, including tenosynovitis,2–4 tumours,2 4 5 calcified mass4 6 or tophaceous gout.4 7 We also found such cases were common in systemic diseases such as rheumatoid arthritis, diabetes mellitus, gout and so on. Take tenosynovitis for example, transverse sonography of the median nerve at the level of the pisiform bone showed an ovoid hypoechoic reticular structure without swelling. However, the deep tissue of nerve showed hypoechoic swelling (figure 1A). On the longitudinal sonograms, the nerve appeared as a consistent thickness of strip structure without a sudden thinning or thickening (figure1B). However, power Doppler showed increased blood flow signal within the nerve and carpal tunnel (figure1B, C). CSA as a diagnostic criterion will increase the false-negative rate of CTS. 2. Ultrasound also has disadvantages for diagnosis of CTS. As we know, the diagnosis of CTS is based primarily on clinical examination and nerve conduction studies. In the last 20 years, ultrasound has been employed as an important imaging tool for CTS. The value of sonographic assessment for CTS depended mainly on three sonographic techniques: measurement of median nerve CSA at differential locations along the carpal tunnel, structural analysis of the median nerve and bowing of the flexor retinaculum.8 We agree ultrasound can evaluate morphological changes of median nerve and provide a good data support for CTS. More specifically,
ultrasound is not much an evaluation as a diagnostic tool for CTS. The term ‘volume’ mentioned in the title was used inappropriately. The volume of median nerve should be measured on the 3D space image. However, Dejaco et al1 measured CSA of nerves on the 2D image. In order to avoid ambiguity, we proposed to use the term ‘area’. Jiaan zhu, Fang Liu Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai Institute of Ultrasound in Medicine, Shanghai, China Correspondence to Professor Jiaan zhu, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai Institute of Ultrasound in Medicine, 600 Yishan Road, Shanghai, China; [email protected] Contributors Jz: concept, writing; FL: writing. Competing interests None. Provenance and peer review Not commissioned; internally peer reviewed. To cite zhu J, Liu F. Ann Rheum Dis 2014;73:e16. Received 4 December 2013 Accepted 8 December 2013 Published Online First 20 December 2013
▸ http://dx.doi.org/10.1136/annrheumdis-2013-205038 Ann Rheum Dis 2014;73:e16. doi:10.1136/annrheumdis-2013-205015
REFERENCES 1
2 3 4 5 6 7 8
Dejaco C, Stradner M, Zauner D, et al. Ultrasound for diagnosis of carpal tunnel syndrome: comparison of different methods to determine median nerve volume and value of power Doppler sonography. Ann Rheum Dis 2013;72:1934–9. Chen CH, Wu T, Sun JS, et al. Unusual causes of carpal tunnel syndrome: space occupying lesions. J Hand Surg Eur Vol 2012;37:14–9. Klauser AS, Faschingbauer R, Bauer T, et al. Entrapment neuropathies II: carpal tunnel syndrome. Semin Musculoskelet Radiol 2010;14:487–500. Kang HJ, Jung SH, Yoon HK, et al. Carpal tunnel syndrome caused by space occupying lesions. Yonsei Med J 2009;50:257–61. Ait Essi F, Younsi A, Abkari I, et al. Diffuse tenosenovial giant cell tumor of the wrist revealed by carpal tunnel syndrome: report of a case. Chir Main 2012;31:256–8. Takada T, Fujioka H, Mizuno K. Carpal tunnel syndrome caused by an idiopathic calcified mass. Arch Orthop Trauma Surg 2000;120:226–7. Patil VS, Chopra A. Watch out for ‘pins and needles’ in hands--it may be a case of gout. Clin Rheumatol 2007;26:2185–7. Nakamichi K, Tachibana S. Ultrasonographic findings in isolated neuritis of the posterior interosseous nerve: comparison with normal findings. J Ultrasound Med 2007;26:683–7.
Figure 1 Transverse and longitudinal sonograms of the median nerve at the carpal tunnel. (A) Transverse sonogram of the median nerve at the level of the pisiform bone (cross-sectional area: 7 mm2). (B) Longitudinal sonogram of the median nerve. (C) Transverse sonogram of the carpal tunnel with abundant blood flow signal.
Ann Rheum Dis April 2014 Vol 73 No 4
e16
Downloaded from ard.bmj.com on September 26, 2014 - Published by group.bmj.com
Paying attention to carpal tunnel contents lesions: ultrasound for evaluation of carpal tunnel syndrome Jiaan zhu and Fang Liu Ann Rheum Dis 2014 73: e16 originally published online December 20, 2013
doi: 10.1136/annrheumdis-2013-205015
Updated information and services can be found at: http://ard.bmj.com/content/73/4/e16.full.html
These include:
References
This article cites 8 articles, 3 of which can be accessed free at: http://ard.bmj.com/content/73/4/e16.full.html#ref-list-1
Email alerting service
Receive free email alerts when new articles cite this article. Sign up in the box at the top right corner of the online article.
Notes
To request permissions go to: http://group.bmj.com/group/rights-licensing/permissions
To order reprints go to: http://journals.bmj.com/cgi/reprintform
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