Cadaveric study on the vascular anatomy of the ulnar nerve at the elbow--a basis for anterior transposition?

The clinical results of anterior transposition of the ulnar nerve in compressive ulnar neuropathy have been unsatisfactory. This study aims at qualifying and quantifying the vascular anatomy of the ulnar nerve at the elbow so as to enable us to appreciate the possible effects of anterior transposition of the ulnar nerve. In our study of 16 cadaveric limbs, we found that the average number of nutrient vessels supplying the ulnar nerve is 14.3. The main contributing vessel in the arm is the superior ulnar collateral artery, at the elbow, the inferior ulnar collateral artery proximally, and the posterior ulnar recurrent artery distally. In the forearm, the main supply is from the ulnar artery. The average length of the nutrient vessels ranges from 1 cm at the elbow to about 2.6 cm in the arm. The nutrient vessels at the elbow are short, small and numerous. Blood supply to the nerve is segmental in nature. In our histological study of the nerve at the elbow, we found that overall, there are more vascular channels in the intrinsic system than the extrinsic system (statistical significance p < 0.01). From this study, we were able to postulate that there is devascularisation of the ulnar nerve following an anterior transposition. The significance of the devascularisation will require further studies.