Author response: Progressive neurodegeneration following spinal cord injury: Implications for clinical trials

We agree with Dr. Domingue's observation that the trajectory of recovery after spinal cord injury (SCI) is complex and difficult to predict. We should clarify that in the present study, we investigated the effects of traumatic SCI on neurodegeneration across the neuroaxis.1 However, we and others have shown that in cervical spondolytic myelopathy (i.e., nontraumatic SCI) remote tissue specific cord pathology is also evident.2,3 Surprisingly, the extent of neurodegeneration is similar to traumatic SCI, although these patients with nontraumatic SCI had only mild clinical symptoms.2 This suggests that, in a slow progressive disease (e.g., cervical spondolytic myelopathy), the CNS can compensate for neurodegenerative processes for much longer; however, with time, the competition between processes of reorganization and neurodegeneration is lost in favor of the latter. Nevertheless, the clinical viability of MRI-based structural measures for monitoring and predicting recovery after nontraumatic and traumatic SCI is feasible and will provide a tool to improve our understanding of the disease mechanism, which affects not only the spinal cord but also the brain after SCI.3–5 These new insights will enable us to better predict individual recovery trajectories and identify patients who could profit from further interventions to delay, or even prevent, further clinical deterioration.