Abstract: The invention generally relates to systems and methods for stress testing to failure tubular mesh devices, specifically, one or more stents or mesh grid tubes. A radial compression method of stress to fatigue is developed by placing a tubular medical implant within a lower than normal compliance test vessel. A radial expansion method of stress to fatigue is developed by placing higher than normal compliance tubes within a tubular medical implant. A method for radial expansion and radial compression is conducted by placing a higher than normal compliance tube through the mesh device and the placing the tube and device within a lower than normal compliance test vessel. Each method is tested on a tester that operates by delivering pulsatile flow with varying pressures, frequencies and testing parameters. Fracture of the test subject is visualized by high speed camera.

Abstract: A method of determining the endurance limit of an implantable medical device is disclosed. The method utilizes a mock vessel that has a compliance that is higher or lower than the normal compliance of a human vessel for which the device is to be used. The device is deployed into the mock vessel and a curable liquid is used to form a layer over the device on the surface of the lumen of the mock vessel. High pressure pulsatile pressurization is applied to the lumen of the mock vessel to cause a failure of the implantable medical device. The amount and cycles of pressure necessary to cause a failure may be used to determine the endurance limit of the implantable medical device.

Abstract: A method of determining the endurance limit of an implantable medical device is disclosed. The method utilizes a mock vessel that has a compliance that is higher or lower than the normal compliance of a human vessel for which the device is to be used. The device is deployed into the mock vessel and a curable liquid is used to form a layer over the device on the surface of the lumen of the mock vessel. High pressure pulsatile pressurization is applied to the lumen of the mock vessel to cause a failure of the implantable medical device. The amount and cycles of pressure necessary to cause a failure may be used to determine the endurance limit of the implantable medical device.

Abstract: The invention generally relates to systems and methods for stress testing to failure tubular mesh devices, specifically, one or more stents or mesh grid tubes. A radial compression method of stress to fatigue is developed by placing a tubular medical implant within a lower than normal compliance test vessel. A radial expansion method of stress to fatigue is developed by placing higher than normal compliance tubes within a tubular medical implant. A method for radial expansion and radial compression is conducted by placing a higher than normal compliance tube through the mesh device and the placing the tube and device within a lower than normal compliance test vessel. Each method is tested on a tester that operates by delivering pulsatile flow with varying pressures, frequencies and testing parameters. Fracture of the test subject is visualized by high speed camera.

Abstract: An acute medical particulate testing device for determining particle shed from a medical device during implantation. The device includes a closed loop system through which a solution is forcibly passed. An inlet port allows a catheter-mounted medical device to be incorporated into the flow loop. At least one tortuous passage is provided to replicate the vascular pathway and tortuosity which simulates the turns and bends and rubbing that affect particulate release from an implantable medical device as it is passed through the vasculature. A debubbler is provided to remove air bubbles from the solution before it is passed into a particle counting device that counts particle shed from the medical device during the simulated implantation. A filter having desired porosity removes particles from the solution. A final filter system removes all particles and air bubbles from the solution before it is re-circulated through the loop.

Abstract: An acute medical particulate testing device for determining particle shed from a medical device during implantation. The device includes a closed loop system through which a solution is forcibly passed. An inlet port allows a catheter-mounted medical device to be incorporated into the flow loop. At least one tortuous passage is provided to replicate the vascular pathway and tortuosity which simulates the turns and bends and rubbing that affect particulate release from an implantable medical device as it is passed through the vasculature. A debubbler is provided to remove air bubbles from the solution before it is passed into a particle counting device that counts particle shed from the medical device during the simulated implantation. A filter having desired porosity removes particles from the solution. A final filter system removes all particles and air bubbles from the solution before it is re-circulated through the loop.

Abstract: A self-retaining artificial spinal disc is formed of a flexible material and has a peripheral lip or meniscus extending from its top and/or bottom surface. The meniscus/menisci encircle portions of vertebrae adjacent the implant site, to enhance retention of the artificial spinal disc when seated in the spinal column. The meniscus/menisci for example snugly overlie the vertebral portions, and foster a suction seal between the disc and the adjacent vertebrae. The disc may be formed as an integral whole, or as two half-discs joinable by gluing, melting or like methods. In a related method, a self-retaining artificial spinal disc is formed in layers, by pouring and drying measures of liquid disc solution in a mold. A meniscal extension is formed from the disc body. Drugs or salts may be added to the disc layers, for example to provide an artificial spinal disc with time-release antibiotics or a desired porosity.

Abstract: A self-retaining artificial spinal disc is formed of a flexible material and has a peripheral lip or meniscus extending from its top and/or bottom surface. The meniscus/menisci encircle portions of vertebrae adjacent the implant site, to enhance retention of the artificial spinal disc when seated in the spinal column. The meniscus/menisci for example snugly overlie the vertebral portions, and foster a suction seal between the disc and the adjacent vertebrae. The disc may be formed as an integral whole, or as two half-discs joinable by gluing, melting or like methods. In a related method, a self-retaining artificial spinal disc is formed in layers, by pouring and drying measures of liquid disc solution in a mold. A meniscal extension is formed from the disc body. Drugs or salts may be added to the disc layers, for example to provide an artificial spinal disc with time-release antibiotics or a desired porosity.

Abstract: Apparatuses and methods for determining particle shed rates of implantable or inter-dwelling devices are disclosed. Durability test apparatuses with integrated particle counters produce time-dependent particle shed rate profiles. The apparatuses are designed to accommodate pulsatile flow, resembling a heartbeat at the implantable device. In an embodiment, the pulsatile flow is converted to a steady flow before fluid enters the integrated particle counter.

Abstract: A lost candy method for producing polymeric mock human tissue that has to meet an exacting specification comprise producing a batch of cores of a candy material from a sugar composition, and then coating such cores repetitively in pre-polymer material to build up sufficient thickness estimated to be short of or otherwise meeting the specification. After allowing completion of the polymerization process, then testing one polymerized member of the batch for if it meets the specification. If it does, then the remaining members can be tested for it they do too. If not but if things can be remedied by adding additional thickness, then returning to the step of coating with the remaining members of the batch. Otherwise, then returning to the beginning by of producing anew a fresh batch of cores of the candy material, and then coating such repetitively in said pre-polymer material except fewer times as originally.

Abstract: A test apparatus provides pulsatile flows that replicate the human cardiovascular system for qualifying implantable cardiovascular devices before implantation in a patient. A pump provides flow pulses to a mock left ventricle, a mock aortic valve, and a mock aorta. A loop from the ventricle to the aorta bypasses the mock aortic valve and affords connection of the test device. The mock aorta comprises elastic tube sections serially connected in progressively diminishing diameters, and interconnected by adjustable flow restrictors. Each elastic tube section shows about 7% to 12% inside-diameter expansion for 100 mm mercury step increase. A designer's choice over the elasticity of the tube sections and a user's control over the flow restrictor(s) allows the user to shape various target waveforms in regards of flowrate and pressure against time as well as the peaks and drop-off forms in addition.

Abstract: An ultrasound calibrator apparatus and method for calibrating ultrasound equipment. The apparatus includes a pair of opposed bellows oscillatorily transferring a fluent medium back and forth through a channel with a well-defined cross-sectional area such that the flow velocity therethrough is known. A probe in communication with ultrasound equipment to be tested is submerged in a reservoir which is situated in close proximity to the channel such that the flow velocity can be measured therewith. The ultrasound equipment is then adjusted to correct the discrepancies between the known and measured velocities so as to calibrate the ultrasound equipment.

Abstract: A dynamic vascular compliance tester (change in radius with change in pressure) comprises an oscillatorily driven bellows to simulate pulsing a fluid pressure within a test specimen and a method of use thereof. The tester includes a high frequency pressure transducer and a pair of linear voltage-to-displacement transducers ("LVDT") providing outputs that are utilized cooperatively to determine the compliance of a test specimen. A first LVDT measures the volume of fluid in each pulse provided by the bellows and a second LVDT measures the change in length of the test specimen during the pulse. The tester also includes an offset drive mechanism that is operably adjustable such that the volume of fluid passing into the test specimen can be altered as desired.

Abstract: Method and apparatus are disclosed for obtaining flow information of a conductive fluid by detecting the streaming potential and analyzing the resultant signal. In a particular embodiment for detecting abnormal blood velocities in the arterial tree, the apparatus includes a flexible sensor having two fixedly spaced apart electrodes and a common mode signal electrode. Each sensor electrode is connected to an input of a differential amplifier and the common electrode is connected to the common input of the differential amplifier. The output signal from the differential amplifier, after filtering and amplification is provided to a recorder or oscilloscope so that it can be compared with the normal or average signal.A particular embodiment of the method is used to detect blood flow abnormalities, either too fast or too slow compared with most healthy individuals of the same age.

Abstract: A method and apparatus are disclosed for sensing the changes in the electrical potential across a double layer. By using a conductive plug comprised of the same material that are in suspension in a fluid, the present method can be used to determine the timing and amount of agents to be added to the liquid to promote the removal of the particle. In one embodiment, the sensor is comprised of two closed chambers, a sensor chamber closed by a porous plug made from the subject material, and a reference chamber closed by a plug that prevents particle dispersion therethrough and also offers a negligible variation in double layer interface potential. An exemplary plug could be comprised of agar. Each chamber includes a corresponding electrode probe and is filled with a conductive solution.