Introduction
Nerve grafting in acute brachial plexus injuries remains an important and viable reconstructive method in restoring elbow flexion. Outcomes can be affected by intraoperative factors such as graft length, number, and donor quality. This study aims to investigate the relationship between different characteristics of nerve grafts and the functional outcomes in C5, C6 brachial plexus injuries.

Material and Methods
Patients were retrospectively collected from 1996 to 2016 in a tertiary medical Center. 40 patients with C5, C6 brachial plexus injuries who received autologous nerve grafting for elbow flexion were included. Patient demographics, injury type, operative procedures, numbers and length of nerve graft were collected. Acceptable outcome was defined as elbow flexion ≥ M3 status. A p value < 0.05 was considered to be statistically significant.

Results
33 (82.5%) patients have reached M3 at elbow flexion, while 28 (70%)s have reached M4. Average time to recovery was 18.65 months. In univariate analysis, younger patients and more cables used in nerve grafting tended to recover to M4 (p=0.02 and 0.096 respectively). In Cox regression analysis, a longer nerve graft was associated with unpleasant clinical outcome. (p=0.02, OR 0.624)

Conclusion
Higher number of nerve cables used and a shorter nerve grafts can bring more reliable and acceptable outcomes in elbow flexion reinnervation in acute brachial plexus injuries.