Purpose: This case study was performed to observe the repair outcomes and safety after surgical repair of long-distance peripheral nerve defect in the upper arm by implantation of chitosan-PGA nerve guidance conduits combined MSCs.Methods: A 29 year-old woman,who was injured with 50mm long median nerve defect and 80mm long ulnar nerve defects combined the muscle and blood vessel disruption in the right upper arm.The nerve defect were repaired by implantation of chitosan-PGA nerve guidance conduits joint MSCs in the 40th day after injury.After surgical repair,a series of functional assessments were carried out in different times.Motor function was evaluated by the recovery of the joint movement and strength which supplied by the injured nerves.Sensory recovery was assessed by two-point discrimination and touch test with Semmes-Weinstein monofilament.Autonomic function was monitored by Laser Doppler perfusion imaging(LDPI).We observed changes of nerve conduits and nerve regeneration in human body through MRI,ultrasonic and electrophysiological.Blood and urinary routine tests,serum biochemical examinations were taken to monitor the safety of the nerve graft after surgery.Results: 1 year post-implantation,the cutaneous blood perfusion of the right hand increased.the range of the wrist flexion increased.pain test and touch test with monofilament of the finger restored.the results indicated that the function of the injured median nerve is in recovery,but the function supplied by ulnar nerve didnt improve.MRI and ultrasonic showed nerve conduits were absorbed and the atypical regeneration of nerve fibers.No anomalies in blood and urinary routine and serum biochemical examinations were detected.No complications were observed.Conclusions: The results indicate that as an alternative to nerve autografts,chitosan-PGA nerve guidance conduits combined MSCs could be a effective and safe choice for repairing extended nerve defects.