256 Direct Hemi-Hypoglossal Nerve and Hypoglossal Nerve for Suprascapular Nerve/Proximal Brachial Plexus Neurotization: A Cadaveric Feasibility Study

INTRODUCTION: Partial restoration of shoulder function is important in upper brachial plexus lesions, and the suprascapular nerve (SSN) is often the target for such neurotization procedures. Although there is an extensive history of peripheral nerve surgeons using the hypoglossal nerve (HN) for various local nerve transfers, some have reported using this nerve as a donor for upper brachial plexus grafting procedures. METHODS: Fifteen adult cadavers (30 sides) were used. On 15 sides, the HN was dissected anteriorly to the midline, cut, and then transposed. On the remaining sides, the nerve was hemisected longitudinally into two equal parts, and the cut inferior portion also swung inferiorly. The cut end of the HN was brought toward the proximal SSN, the C5 and C6 cervical nerve roots, and the upper trunk. RESULTS: The mean diameter and length of the HN were 2.1 mm and 72.8 mm, respectively. The mean diameter of the proximal SSN was 2.7 mm. Successful, tension-free transposition to the C5 and C6 nerve roots was achieved on all sides. The average extra length of the HN for a C5 and C6 root transposition was 8 mm and 5.2mm, respectively. The distal HN reached the upper trunk on all but two sides (6.7%) and the proximal SSN on all but four sides (13.3%). This technique resulted in a mean additional length to the SSN of 35 mm. CONCLUSIONS: To our knowledge, the use of the HN as a transpositional graft for direct SSN neurotization has not been previously described. The HN, or hemi-HN, should be considered as a donor nerve to restore SSN function in the majority of patients. Additionally, the it may be transferred to the C5 and C6 roots and upper trunk of the brachial plexus.