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Letters to the Editor |
Department of Orthopedics, Veterans Army Hospital, Monis Petraki 12, 11521 Athens, Greece. e-mail: cky@ath.forthnet.gr
Editor:
I read with interest the article by Dr Jacobson and colleagues in the September 2001 issue of Radiology (1).
I would like to contribute my personal experience and a few comments on the imaging diagnosis of the snapping triceps syndrome, which have already been published elsewhere (2,3). My experience involves two cases with symptomatic medial elbow snapping, in which the diagnosis was confirmed by using real-time dynamic ultrasonography (US) and magnetic resonance (MR) imaging. The first patient was a 48-year-old nurse with bilateral symptomatic elbow snapping, and the second patient was a 28-year-old Olympic-class swimmer with unilateral symptoms but bilateral snapping. The clinical diagnosis was made by using the description of the pathogenesis and the treatment of this syndrome by Spinner et al (4,5). The diagnosis was established with MR imaging performed in full flexion and extension, as well as dynamic US imaging (HDI-5000; Philips Medical Systems, Best, the Netherlands), with a 7.5-MHz transducer. MR imaging mandates full elbow flexion to depict the nerve and muscle translocation. Elbow flexion less than 100° is inadequate for revealing the translocation.
In my opinion, MR imaging remains the examination of choice: The image quality is better, the anatomic relationships are more familiar to the orthopedic surgeon, and the technique is less operator dependent. On the other hand, one has to admit that US imaging, although an operator-dependent technique, offers the great advantage of dynamic real-time imaging with minimal cost, is time saving, and can be applied more often than MR imaging.
For the examination, my patients are asked to lie on the examination couch, because in this position they tend to be more comfortable and relaxed than when sitting. The US palpation technique is used to locate the area of maximum tenderness at the medial epicondyle. Imaging of both elbows is mandatory because the snapping triceps syndrome is often bilateral. The diagnosis of snapping triceps can be made reliably with clinical examination, which confirms the presence of the characteristic double click with elbow flexion. This double click distinguishes the snapping triceps syndrome from the isolated ulnar nerve translocation (3). The transducer must always be perpendicular to the medial head of the triceps and the humerus. For this purpose, the transducer is placed on the medial epicondyle, revealing its characteristic anechoic texture. Effort is made to obtain transverse views of the dislocating structures. Once translocation is documented, oblique views may help to demonstrate it more evidently. The alteration of the transducer position as shown in figure 1 by Dr Jacobson and colleagues (1) may distort the image orientation.
In conclusion, I believe that in expert hands, US provides invaluable information, but its use in the diagnosis of snapping triceps syndrome requires the accumulation of additional experience.
REFERENCES
,
Andrew W. Jeffers, MD,,
David P. Fessell, MD,* and
Curtis W. Hayes, MD*
Departments of Radiology* and Orthopedic Surgery, University of Michigan Medical Center, 1500 East Medical Center Drive, TC-2910G, Ann Arbor, MI 48109-0326. e-mail: jjacobsn@umich.edu
My colleagues and I would like to thank Dr Yiannakopoulos for the interest in our article (1). Although the use of sonography versus MR imaging in the diagnosis of musculoskeletal abnormalities is debated, we believe there is a role for both imaging methods. However, in the diagnosis of snapping triceps syndrome, we prefer sonography (1). In a letter to the Editor (2), the importance of active elbow flexion, with and without resistance, was brought to our attention. This maneuver favors the use of sonography over MR imaging. In addition, one may debate the statement that "image quality is better" with MR imaging. Commercially available US probes achieve an in-plane resolution of 200–450 µm, which is greater than the in-plane resolution of approximately 300 µm as seen with standard clinical MR imaging (3). With high-frequency US probes (12–15 MHz), detailed anatomy can be visualized, such as individual hypoechoic neuronal fascicles of a peripheral nerve (4). The superficial location of the cubital tunnel and its contents is ideal for sonographic evaluation.
With regard to the sonographic technique in the diagnosis of snapping triceps syndrome, we agree that transverse imaging is essential. The transducer position in figure 1 of our article (1) is transverse to the humeral shaft, in a plane between the olecranon process and the medial epicondyle.
With standardized technique as described in our article (1), we believe that the diagnosis of snapping triceps syndrome and differentiation from isolated ulnar nerve dislocation can be made accurately. We perform this technique with every elbow US examination regardless of patient history, which further familiarizes one with normal anatomy and sonographic technique.
REFERENCES
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