CUBITAL TUNNEL SYNDROME
Ulnar nerve compression at the elbow (cubital tunnel syndrome) is the second most common compression neuropathy in the upper extremity. The ulnar nerve runs posterior to the medial epicondyle and can be compressed at several points along its course. Patients initially complain of numbness and tingling most often in the small and ring fingers. As symptoms progress, medial elbow pain becomes more prominent, as well as clumsiness in the hand. Advanced cases of ulnar nerve compression at the elbow will demonstrate atrophy of the intrinsic muscles of the hand (most obvious involving the first dorsal interrosseous) and clawing of the fourth and fifth digits. Physical examination focuses on a detailed sensory examination and muscle testing of the intrinsic muscles of the hand. Instability of the ulnar nerve with elbow flexion should be evaluated. A Tinel sign over the ulnar nerve in the cubital tunnel as well as elbow flexion/compression testing can help localize the location of ulnar nerve compression at the level of the elbow. Electrodiagnostic testing can help make an accurate diagnosis and evaluate for more proximal and/ or distal points of compression.
Initial treatment in a patient without weakness/atrophy consists of diminishing traction and compression of the ulnar nerve at the cubital tunnel. Night-time splinting with the elbow at approximately 30 degrees, an elbow pad during the day to avoid direct trauma to the nerve, and activity modification often leads to dramatic symptom relief. Patients failing at least 3 months of consistent nonoperative treatment and/or patients presenting with more advanced symptoms should be considered for operative decompression. There are numerous surgical options from in situ decompression to medial epicondylectomy to anterior transposition of the ulnar nerve either subcutaneous or submuscular. Recent reports have demonstrated positive results with endoscopic ulnar nerve decompression, but further studies are needed.
Less commonly, the ulnar nerve can be compressed at the level of the wrist (at the Guyon canal). The symptoms are similar to those of cubital tunnel syndrome, but medial elbow pain and numbness along the dorsum of the hand are absent. The ulnar nerve can be compressed at different points in reference to the hook of the hamate, and symptoms can vary from pure motor or sensory changes to combined losses. Physical examination includes a positive Tinel sign at the ulnar wrist, and careful palpation must evaluate for masses (ganglion/lipoma) and rule out hypothenar hammer syndrome. Conservative treatment is the initial management, followed by surgical decompression.