[Diagnostic nerve ultrasonography]

Ulnar Neuropathy at the Elbow: From Ultrasound Scanning to Treatment

Ulnar neuropathy at the elbow (UNE) is commonly encountered in clinical practice. It results from either static or dynamic compression of the ulnar nerve. While the retroepicondylar groove and its surrounding structures are quite superficial, the use of ultrasound (US) imaging is associated with the following advantages: (1) an excellent spatial resolution allows a detailed morphological assessment of the ulnar nerve and adjacent structures, (2) dynamic imaging represents the gold standard for assessing the ulnar nerve stability in the retroepicondylar groove during flexion/extension, and (3) US guidance bears the capability of increasing the accuracy and safety of injections. This review aims to illustrate the ulnar nerve's detailed anatomy at the elbow using cadaveric images to understand better both static and dynamic imaging of the ulnar nerve around the elbow. Pathologies covering ulnar nerve instability, idiopathic cubital tunnel syndrome, space-occupying lesions (e.g., ganglion, heterotopic ossification, aberrant veins, and anconeus epitrochlearis muscle) are presented. Additionally, the authors also exemplify the scientific evidence from the literature supporting the proposition that US guidance is beneficial in injection therapy of UNE. The non-surgical management description covers activity modifications, splinting, neuromobilization/gliding exercise, and physical agents. In the operative treatment description, an emphasis is put on two commonly used approaches-in situ decompression and anterior transpositions.

[Revision surgery for carpal and cubital tunnel syndrome]

BACKGROUND

Carpal tunnel syndrome, a compressive neuropathy of the median nerve at the wrist and cubital tunnel syndrome, a compressive neuropathy of the ulnar nerve at the elbow, are the two most common peripheral nerve compression syndromes. Chronic compressive neuropathy of peripheral nerves causes pain, paraesthesia and paresis. Treatment strategies include conservative options, but only surgical decompression can resolve the mechanical entrapment of the nerve with proven good clinical results. However, revision rates for persistent or recurrent carpal tunnel syndrome is estimated at around 5% and for refractory cubital tunnel syndrome at around 19%. Common causes for failure include incomplete release of the entrapment and postoperative perineural scarring.

THERAPY

Precise diagnostic work-up is obligatory before revision surgery. The strategy of revision surgery is first complete decompression of the affected nerve and then providing a healthy, vascularized perineural environment to allow nerve gliding and nerve healing and to avoid recurrent scarring. Various surgical options may be considered in revision surgery, including neurolysis, nerve wrapping and nerve repair. In addition, flaps may provide a well vascularized nerve coverage in the case of recurrent carpal tunnel syndrome. In the case of recurrent cubital tunnel syndrome, anterior transposition of the ulnar nerve is mostly performed for this purpose.

RESULTS

In general, revision surgery leads to improvement of symptoms, although the outcome of revision surgery is less favourable than after primary surgery and complete resolution of symptoms is unlikely.