gms | German Medical Science

Objective: Beside clinical examination and electrophysiological studies the role of imaging of morphologic lesion in peripheral nerve disorders becomes more important. Due to recent developments and the availability of MRI and high-resolution ultrasonography these imaging modalities are getting more import in the diagnostic workflow of nerve lesions. The objective of this study was the correlation between the intraoperative anatomical findings, the preoperative electrophysiological diagnostics and the MRI and ultrasonography images.

Methods: Between October 2007 and November 2009, 25 patients with disorders of the ulnar nerve (numbness, weakness, atrophy and neuropathic pain) were included. We performed standardized high-resolution ultrasound (15 MHz) examination with measurement of the nerve as well as evaluation and measurement of the perineural tissue in the Cubital tunnel. Furthermore, anatomic characteristics, such as i.e. an aberrant muscle in the sulcus were recorded. MR neurography of the ulnar nerve was accomplished in 17 cases. In 16 cases an endoscopic cubital tunnel release has been carried out. Two patients underwent an open cubital tunnel release.

Results: MR neurography and ultrasonography detected the relative position of the ulnar nerve in the sulcus and cubital tunnel equally. The ultrasonography is able to depict real-time dynamic morphological information i.e. subluxation in addition. Nerve imaging on a fascicular level could be realised with the applied methods only with ultrasonography. A swelling of the nerve (in terms of a pseudoneuroma) was detected both image modalities – MRI & ultrasonography – in 9 cases, however two false-positive cases were revealed in the intraoperative findings. Aberrant muscles compressing the ulnar nerve were detected in 7 cases by ultrasonography, none by MRI. During cubital tunnel release we found aberrant muscles in 10 cases (3 cases false-negative in ultrasonography). In one case a tumor of the ulnar nerve was detected first by ultrasonography and later verified by MRI.

Conclusions: High-resolution ultrasonography & MR neurography supplements the preoperative diagnostics of peripheral nerve lesions. In peripheral nerve entrapment, according to our findings the high-resolution-ultrasonography is a readily applicable valid imaging method to depict the morphological information. Due to the progress in ultrasonographic technology the results in spatial and contrast resolution is an advantage over the MRI by the time.