Cubital Tunnel Syndrome
Cubital tunnel syndrome (also known as ulnar neuropathy and ulnar nerve entrapment) is caused by compression of the ulnar nerve in the cubital tunnel. It is the second most common peripheral nerve entrapment syndrome after carpal tunnel syndrome with an annual incidence rate of approx. 25 cases per 100,000 patients. In most cases, the cause of the problem is unknown and may stem from an elbow joint injury many years prior, elbow arthrosis, or chronic nerve compression damage. Further pathogenetic factors are recurring or external pressures favoured by a shallow ulnar groove in the elbow and (sub) luxation of the ulnar nerve during flexion of the lower arm.
Diagnosis and Examination
The typical cubital tunnel syndrome symptoms identified by the physician during the examination of patients are sensory disturbances and numbness in the little finger, the little finger side of the ring fingers and the little finger side of the lateral hand, especially during flexion of the elbow joint. Long-term entrapment can lead to loss of strength (paresis) in the hand, e.g., when writing and when spreading the fingers. Ultimately, muscle atrophy develops, which is most easily identifiable between the thumb and index finger.
Following clinical examination by a hand surgeon, the diagnosis is usually confirmed by a nerve conduction velocity test carried out by a neurologist. Also, ultrasound can be used to display size and positional changes of the ulnar nerve at the elbow. Additionally, cystic changes located in the joint-adjacent region (e.g. ganglion cysts) can be identified. Magnetic resonance imaging (MRI) is also very informative in the early stages of the disease. MR neurography can provide additional information relating to the extent of nerve damage. Especially with previous injuries to the elbow region, conventional x-ray diagnostics should not be overlooked for the detection of calcifications and arthrosis-related changes.os
Measures such as short-term immobilisation and cushioning using a splint may relieve symptoms. Also, antiphlogistic medication, (e.g.,Ibuprofen, Diclofenac, Cox-2 inhibitors, etc.) and supportive physical therapies can be beneficial.
If the conservative treatment of the sulcus ulnaris syndrome does not lead to a reduction in symptoms and pain levels, then surgical treatment of cubital tunnel syndrome is indicated. The decision should be based on the examination to determine the severity of nerve damage, which should take place within 6 weeks. The operative treatment must include the decompression of all affected ulnar nerve regions in the elbow. Timely operative treatment results in permanent improvement (cure), however, any existing muscle atrophy is not reversible or may only be slightly improved.
Simple ulnar nerve decompression is still the most commonly performed procedure. This involves exposing and then releasing the nerve from the anatomical structures causing the compression using a 4-6 cm long incision at the elbow. Repositioning is only necessary in rare cases e.g. luxation of the ulnar nerve from the ulnar sulcus during intraoperative flexion.
Endoscopic operative techniques require only a small incision (approx. 20 mm), but nevertheless enable extensive nerve decompression (20 – 30 cm).
The suture material is removed after 12-14 days. The area is wrapped in a padded cotton wool bandage for 1 week and physiotherapy can begin early. Treatment using a splint and two-weeks of immobilisation is only necessary if the nerve was repositioned. Non-manual activities can be resumed after 2 to 3 weeks, and even earlier when an endoscopic technique was used.