An anatomic study of the distal spinal accessory nerve (SAN) to determine the number of myelinated axons and feasibility of posterior harvest for direct neurotization of distal targets was performed. Ten fresh human cadavers were studied. A supraclavicular approach was performed followed by a posterior approach. The relationship of the SAN to bony landmarks (T1 spinous process, acromioclavicular joint, posterolateral corner of the acromium, and angle at the superior medial border of the scapula) as well as maximal harvestable length was recorded. After posterior dissection, the SAN was mobilized and the ability to reach both anterior infraclavicular and posterior targets was assessed. Axon counts were also performed at the proximal, mid, and distal points along the course of the nerve. The posteriorly harvested SAN was identified reliably with respect to bony landmarks. When harvested posteriorly, the SAN could reach the infraclavicular part of the brachial plexus (i.e., terminal branches), and posteriorly, the suprascapular nerve (SSN) both proximal and distal to the suprascapular ligament, the latter for selective reinnervation of the infraspinatus branch. The average number of myelinated fibers at the proximal end of the nerve was 1,328 axons, at the mid-way point was 1,021 axons, and at terminal end of the nerve was 817 axons. Harvest of the SAN from a posterior approach based on these landmarks is feasible, allowing direct transfer of the nerve to the infraclavicular brachial plexus and to the SSN both proximal and distal to the suprascapular ligament, without the use of interposition nerve grafts. Clin. Anat. 20:899-904, 2007. V V C 2007 Wiley-Liss, Inc.

Three children, 1 with medulloblastoma, 1 with anaplastic cerebellar tumor, and 1 with acute lymphocytic leukemia, received craniospinal irradiation with an estimated cord dose between 1,100 and 1,200 rets. All 3 patients after a latent period of seven to eight months developed subacute transverse myelopathy. The myelopathy was cervical in 2 patients and thoracic in 1. Spinal fluid examination showed high protein levels in 2 patients. Myelography demonstrated a swollen cord in 2 patients and normal appearance in 1. Autopsy in 1 patient disclosed a necrotizing myelopathy. The findings suggest that children tolerate less well than adults what previously have been considered safe doses of radiation to the spinal cord.

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