Posterior approach technique for accessory-suprascapular nerve transfer: a cadaveric study of the anatomical landmarks and number of myelinated axons.

Accessory-suprascapular nerve transfer by the anterior supraclavicular approach technique was suggested to ensure transferrance of the spinal accessory nerve to healthy recipients. However, a double crush lesion of the suprascapular nerve might not be sufficiently demonstrated. In that case, accessory-suprascapular nerve transfer by the posterior approach would probably solve the problem. The aim of this study was to evaluate the anatomical landmarks and histomorphometry of the spinal accessory and suprascapular nerve in the posterior approach. Dissection of fresh cadaveric shoulder in a prone position identified the spinal accessory and suprascapular nerve by the trapezius muscle splitting technique. After that, nerves were taken for histomorphometric evaluation. The spinal accessory nerve was located approximately halfway between the spinous process and conoid tubercle. The average distance from the conoid tubercle to the suprascapular nerve (medial edge of the suprascapular notch) is 3.3 cm. The mean number of myelinated axons of the spinal accessory and suprascapular nerve was 1,603 and 6,004 axons, respectively. The results of this study supported the brachial plexus reconstructive surgeons, who carry out accessory-suprascapular nerve transfer by using the posterior approach technique. This technique is an alternative for patients who have severe crushed injury of the shoulder or suspected double crush lesion of the suprascapular nerve.