Cubital tunnel syndrome (CuTS) is the second most common peripheral nerve compression syndrome. In German-speaking countries, cubital tunnel syndrome is often referred to as sulcus ulnaris syndrome (retrocondylar groove syndrome). This term is anatomically incorrect, since the site of compression comprises not only the retrocondylar groove but the cubital tunnel, which consists of 3 parts: the retrocondylar groove, partially covered by the cubital tunnel retinaculum (lig. arcuatum or Osborne ligament), the humeroulnar arcade, and the deep flexor/pronator aponeurosis. According to Sunderland , cubital tunnel syndrome can be differentiated into a primary form (including anterior subluxation of the ulnar nerve and compression secondary to the presence of an anconeus epitrochlearis muscle) and a secondary form caused by deformation or other processes of the elbow joint. The clinical diagnosis is usually confirmed by nerve conduction studies. Recently, the use of ultrasound and MRI have become useful diagnostic tools by showing morphological changes in the nerve within the cubital tunnel. A differential diagnosis is essential in atypical cases, and should include such conditions as C8 radiculopathy, Pancoast tumor, and pressure palsy. Conservative treatment (avoiding exposure to external noxes and applying of night splints) may be considered in the early stages of cubital tunnel syndrome. When nonoperative treatment fails, or in patients who present with more advanced clinical findings, such as motor weakness, muscle atrophy, or fixed sensory changes, surgical treatment should be recommended. According to actual randomized controlled studies, the treatment of choice in primary cubital tunnel syndrome is simple in situ decompression, which has to be extended at least 5-6 cm distal to the medial epicondyle and can be performed by an 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. When the luxation is painful, or when the ulnar nerve actually "snaps" back and forth over the medial epicondyle of the humerus, subcutaneous anterior transposition may be performed. In cases of severe bone or tissue changes of the elbow (especially with cubitus valgus), the anterior transposition of the ulnar nerve may again be indicated. In cases of scarring, submuscular transposition may be preferred as it provides a healthy vascular bed for the nerve as well as soft tissue protection. Risks resulting from transposition include compromise in blood flow to the nerve as well as kinking of the nerve caused by insufficient proximal or distal mobilization. In these cases, revision surgery is necessary. Epicondylectomy is not common, at least in Germany. Recurrence of compression on the ulnar nerve at the elbow may occur. This review is based on the German Guideline "Diagnose und Therapie des Kubitaltunnelsyndroms" ( www.leitlinien.net ).

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.

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 [159] 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.