Pathology as a Core Discipline in the Biological Evaluation of Medical Devices

The device development process encompasses an intersection of biological, physical, and engineering sciences principles culminating in translation of data from nonclinical animal studies to predict potential tissue responses in human patients. Evaluation of tissue reactions to the implanted device relies heavily on the core discipline of toxicologic pathology. Historically and currently, a disconnect between physical and biological scientists is highlighted by the frequent miscommunications due to differences in scientific language and divergent approaches to animal study design and/or data generation and interpretation. To facilitate communication among biologists, engineers, and materials scientists in the medical device community, this article provides fundamental principles and key resources necessary for rational pathology evaluation of tissue responses to implanted devices from the expert perspective of experienced toxicologic pathologists. The unique contributions of toxicologic pathologists to developing and marketing medical devices will be discussed, emphasizing the role of expert pathologists in balancing scientific issues with respect to evaluating biological responses and regulatory considerations. Additionally, discrepancies will be addressed that may arise if regulatory guidance is applied rigidly rather than adjusted as warranted by the context-specific evidence to best answer particular safety-related questions.