MRI Diffusion Tensor Tractography to Monitor Peripheral Nerve Recovery After Severe Crush or Cut/Repair Nerve Injury

It is estimated that up to 5% of all admissions to level one trauma centers have a peripheral nerve injury. These peripheral nerve injuries may have devastating impacts on quality of life and require months or years to regain function. Neurotmesis, or peripheral nerve transection, is a common injury, with singly cut nerve lacerations accounting for over 60% of the peripheral nerve surgical interventions in civilian studies. For recovery to occur in these patients, axons must grow from the site of repair to the target tissues, a length of up to a meter in humans. By that time, revisional surgery may not be a viable option due to the onset of irreversible muscle atrophy - a transected nerve is estimated to induce a loss of achievable function of approximately 1% for every 6 days of delay. The scenario is even worse for more proximal nerve injuries, such as those that occur in the brachial plexus. The investigators aim is to longitudinally assess diffusion tensor tractography (DTI) in order to optimize, validate, and translate the ability of DTI to monitor and, more importantly, predict nerve regrowth following trauma and surgical repair. The overall objective of this study is to evaluate the ability of (DTI) to monitor and, more importantly, predict nerve regrowth following crush or cut with surgical repair. The investigators hypothesize that the additional information available via DTI will improve our ability to monitor and predict nerve regrowth following surgical repair or severe crush injury, guiding clinical management either toward or away from surgical intervention.