Diagnosing PCB(A) Deficiencies in Medical Instruments During Reprocessing and Sterilization Cycles

Medical devices and instruments used in surgical procedures require sterilization and cleaning to allow their use in multiple surgeries. Any device or instrument that comes in contact with the patient, or has exposure to biological materials, requires cleaning and sterilization as a standard protocol before they can be used again. Removal of all biological materials, pathogens, debris, and contaminants from the medical device is an absolute requirement. The sterilization procedures may involve the use of harsh chemicals, high temperatures and moisture, high pressure environments, as well as vibrational frequencies, not necessarily all together. These methods have a detrimental effect on the life of the electronics included in the medical devices. These requirements are unlike anything that product life testing of electronics in the consumer and industrial fields will encounter. As such, most electronics used in medical devices face conditions which they were never explicitly designed for. Traditionally, most medical instruments that faced such reprocessing, either had very limited electronics, or had limited usage of high-density PCB (Printed Circuit Board) technologies which would be subjected to multiple such reprocessing cycles. Surgical endoscopes used in Robotic Surgeries are the exception, as they require high density, high complexity electronics packaged tightly within very small spaces (5mm-8mm diameter tubes) and are required to survive and function after undergoing multiple rounds of reprocessing and sterilization. Such an application exposes deficiencies and limitations of PCB technologies in a manner not seen in typical consumer or industrial applications. This paper seeks to highlight the unique challenges faced by PCB's and electronic components under such sterilization regimes. It also seeks to identify best design practices and technologies in PCB manufacturing for such applications, and identify what should be avoided.