The purpose of this study was to report the effects of spinal cord compression, ischemia, and distraction on clinical status, and somatosensory (SEP) and neurogenic-motor evoked potentials (NMEPs) in animals. The authors also reported their clinical experience with NMEPs elicited from humans undergoing surgery for spinal deformities. Results from the animal studies indicate that NMEPs are more sensitive and specific to the effects from spinal cord compression, ischemia, and distraction than SEPs. In every situation, NMEPs always correlated with the animal's post-surgical clinical status, while SEPs demonstrated an unacceptable false positive and false negative rate. In the 111 clinical cases in which NMEPs were administered, reliable NMEPs were easily elicited in more than 90% of the cases. In the remaining cases, no reliable NMEPs could be recorded because of procedural errors, which have been resolved. The results from this study suggest that the use of NMEPs should be considered as an adjunct to SEPs when monitoring spinal cord function during surgery.
• A left atrial—femoral artery (LA-FA) bypass system was designed to deliver synchronous pulsatile blood flow. We compared it with nonpulsatile LA-FA bypass in its effectiveness to limit infarct extension after ligation of the left anterior descending coronary artery at its origin in 35 dogs. Nonpulsatile LA-FA bypass resulted in a 70% reduction in the size of infarct. The addition of synchronous diastolic counterpulsation (P—LA-FA) further reduced the size of infarct, when compared with that in controls (95%) or animals that underwent LA-FA bypass (83%). Both LA-FA and P—LA-FA bypasses limited infarct extension and reduced mortality after acute coronary occlusion through effective unloading of the left ventricle. The addition of diastolic counterpulsation to LA-FA bypass led to further significant infarct reduction, when compared with LA-FA bypass alone. These effects were most likely secondary to improvements in myocardial blood flow distribution. (Arch Surg1983;118:965-969)
This editorial refers to ‘Clinical trial design principles and endpoint definitions for transcatheter mitral valve repair and replacement: part 1: clinical trial design principles’†, by G.W. Stone et al. , doi:10.1093/eurheartj/ehv281 and ‘Clinical trial design principles and endpoint definitions for transcatheter mitral valve repair and replacement: part 2: endpoint definitions’‡, by G.W. Stone et al. , doi:10.1093/eurheartj/ehv333.
The U.S. Food and Drug Administration (FDA) is responsible for protecting and promoting the public health of U.S. citizens. In keeping with this mission, the FDA's Center for Devices and Radiological Health (CDRH) is tasked with ensuring the safety, effectiveness, and quality of medical devices; fostering innovation; and providing the public with accurate scientific information about the products they oversee throughout the total product life cycle. To help fulfil its mission, the CDRH has an ongoing interest in promoting the quality and efficiency of clinical trials. Clinical trials that produce high levels of valid scientific evidence to meet the regulatory approval threshold of reasonable assurance of safety and effectiveness are dependent on excellent trial design and execution. To this end, clearly defined clinical events and meaningful study outcome endpoints are essential elements for trials submitted for regulatory review. Collaborative efforts among multiple stakeholders to reach agreement on …
