Neurosurgery
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Review
Intraoperative nerve action potential recordings: technical considerations, problems, and pitfalls.
The purpose of this article is to provide our experience with intraoperative nerve action potential (NAP) recordings. In particular, we focus on a discussion of the technical considerations of intraoperative NAP with emphasis on identifying and remedying problems and pitfalls. ⋯ Visual inspection of a nerve lesion in continuity can be misleading. Although there is no "head-to-head" comparison of our data with data obtained without the use of intraoperative NAP recordings, we feel strongly that with experience and knowledge of the problems and pitfalls regarding intraoperative recording techniques, one may take advantage of the great benefits of this very useful and informative surgical tool.
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With improvements in endovascular techniques, fewer aneurysms are treated by surgical clipping, and those aneurysms targeted for open surgery are often complex and difficult to treat. We devised a hollow, 3-dimensional (3D) model of individual cerebral aneurysms for preoperative simulation and surgical training. The methods and initial experience with this model system are presented. ⋯ Using the hollow 3D models to simulate clipping preoperatively, we could treat the aneurysms confidently during live surgery. These models allow easy and concrete recognition of the 3D configuration of aneurysms and parent vessels.
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We developed an augmented reality system that enables intraoperative image guidance by using 3-dimensional (3D) graphics overlaid on a video stream. We call this system DEX-Ray and report on its development and the initial intraoperative experience in 12 cases. ⋯ The system was perceived as an improved navigational experience because the augmented see-through effect allowed direct understanding of the surgical anatomy beyond the visible surface and direct guidance toward surgical targets.
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Methods were invented that made it possible to image peripheral nerves in the body and to image neural tracts in the brain. The history, physical basis, and dyadic tensor concept underlying the methods are reviewed. Over a 15-year period, these techniques-magnetic resonance neurography (MRN) and diffusion tensor imaging-were deployed in the clinical and research community in more than 2500 published research reports and applied to approximately 50,000 patients. Within this group, approximately 5000 patients having MRN were carefully tracked on a prospective basis. ⋯ MRN and diffusion tensor imaging neural tract imaging have been validated as indispensable clinical diagnostic methods that provide reliable anatomic pathological information. There is no alternative diagnostic method in many situations. With the elapsing of 15 years, tens of thousands of imaging studies, and thousands of publications, these methods should no longer be considered experimental.
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Traumatic brain injury (TBI) causes an increase in matrix metalloproteinases (MMPs), which are associated with neuroinflammation, blood-brain barrier disruption, hemorrhage, and cell death. We hypothesized that patients with TBI have an increase in MMPs in ventricular cerebrospinal fluid (CSF) and plasma. ⋯ We show that MMPs are increased in the CSF of TBI patients. Although the number of patients was small, the results were robust and clearly demonstrated increases in MMP-3 and MMP-9 in ventricular CSF in TBI patients compared with controls. Although these preliminary results will need to be replicated, we propose that MMPs may be important in blood-brain barrier opening and hemorrhage secondary to brain injury in patients.