[Diagnosis and therapy of cubital tunnel syndrome--state of the art]. / Aktueller Stand der Diagnostik und Therapie des Kubitaltunnelsyndroms.

ABSTRACT

The cubital tunnel syndrome is one of the most widespread compression syndromes of a peripheral nerve. In German-speaking countries it is known as the sulcus ulnaris syndrome (retrocondylar groove syndrome), which is anatomically incorrect. The cubital tunnel consists of the retrocondylar groove, the cubital tunnel retinaculum (Lig. arcuatum or Osborne band), the humeroulnar arcade and the deep flexor/pronator aponeurosis. According to Sunderland it can be divided into a primary form (including the ulnar luxation and the epitrocheoanconaeus muscle) and a secondary form caused by deformation or other processes of the elbow joint. The diagnosis has to be confirmed by a thorough clinical examination and nerve conduction studies. Neurosonography and MRI are becoming more and more important with improving resolution and enable the direct identification of morphological changes. Differential diagnosis is essential in atypical cases, especially C8 syndrome and pressure palsy. Double crush (double compression syndrome) may occur. Operative treatment is more effective than conservative treatment, which consists primarily of the prevention of exposure to external noxes. According to actual randomised controlled studies the therapy of choice of the primary form in most cases is the simple in situ decompression of the ulnar nerve in the cubital tunnel. This has to be extended at least up to 5-6 cm distally of the medial epicondyle and can be performed in the open or endoscopic technique, both under local anesthesia. Simple decompression is also the therapy of choice in uncomplicated ulnar luxation and in most post-traumatic cases and other secondary forms. In cases of severe bony or tissue changes of the elbow (especially cubitus valgus) the volar transposition of the ulnar nerve may be indicated. This can be performed in a subcutaneous or submuscular technique. Risks of transposition are impairment of perfusion and, above all, kinking caused by insufficient proximal or distal mobilisation of the nerve has to be avoided. In these cases revision surgery is necessary. The epicondylectomy is not common in our country. Recurrences may occur.