Prospective randomized controlled study comparing simple decompression versus anterior subcutaneous transposition for idiopathic neuropathy of the ulnar nerve at the elbow: part 1 - Bartels, R H; Verhagen, W I; van der Wilt, G J; Meulstee, J; van Rossum, L G; Grotenhuis, J A (Neurosurgery, 2005)