Publications by authors named "Paul Cvancara"

Artificial communication with the brain through peripheral nerve stimulation shows promising results in individuals with sensorimotor deficits. However, these efforts lack an intuitive and natural sensory experience. In this study, we design and test a biomimetic neurostimulation framework inspired by nature, capable of "writing" physiologically plausible information back into the peripheral nervous system.

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Bioelectronic medicine is a promising venue for treatment of disabilities using implantable neural interfaces. Peripheral neurostimulation of residual nerves recently enabled multiple functional benefits in amputees. Despite the preliminary promising impact on patients' life, the over-time stability of implants and the related nerve reactions are unclear.

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Peripheral Nerve Stimulation (PNS) is a promising approach in functional restoration following neural impairments. Although it proves to be advantageous in the number of implantation sites provided compared with intramuscular or epimysial stimulation and the fact that it does not require daily placement, as is the case with surface electrodes, the further advancement of PNS paradigms is hampered by the limitation of spatial selectivity due to the current spread and variations of nerve physiology. New electrode designs such as the Transverse Intrafascicular Multichannel Electrode (TIME) were proposed to resolve this issue, but their use was limited by a lack of innovative multichannel stimulation devices.

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Objective: Micro-fabricated neural interfaces based on polyimide (PI) are achieving increasing importance in translational research. The ability to produce well-defined micro-structures with properties that include chemical inertness, mechanical flexibility and low water uptake are key advantages for these devices.

Approach: This paper reports the development of the transverse intrafascicular multichannel electrode (TIME) used to deliver intraneural sensory feedback to an upper-limb amputee in combination with a sensorized hand prosthesis.

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Lower limb amputation (LLA) destroys the sensory communication between the brain and the external world during standing and walking. Current prostheses do not restore sensory feedback to amputees, who, relying on very limited haptic information from the stump-socket interaction, are forced to deal with serious issues: the risk of falls, decreased mobility, prosthesis being perceived as an external object (low embodiment), and increased cognitive burden. Poor mobility is one of the causes of eventual device abandonment.

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Conventional leg prostheses do not convey sensory information about motion or interaction with the ground to above-knee amputees, thereby reducing confidence and walking speed in the users that is associated with high mental and physical fatigue. The lack of physiological feedback from the remaining extremity to the brain also contributes to the generation of phantom limb pain from the missing leg. To determine whether neural sensory feedback restoration addresses these issues, we conducted a study with two transfemoral amputees, implanted with four intraneural stimulation electrodes in the remaining tibial nerve (ClinicalTrials.

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Objective: Hand amputation is a highly disabling event, which significantly affects quality of life. An effective hand replacement can be achieved if the user, in addition to motor functions, is provided with the sensations that are naturally perceived while grasping and moving. Intraneural peripheral electrodes have shown promising results toward the restoration of the sense of touch.

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Objective: The aim of the paper is to objectively demonstrate that amputees implanted with intraneural interfaces are truly able to feel a sensation in the phantom hand by recording "phantom" somatosensory evoked potentials from the corresponding brain areas.

Methods: We implanted four transverse intrafascicular multichannel electrodes, available with percutaneous connections to a multichannel electrical stimulator, in the median and ulnar nerves of two left trans-radial amputees. Two channels of the implants that were able to elicit sensations during intraneural nerve stimulation were chosen, in both patients, for recording somatosensory evoked potentials.

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Successful Plastic Surgery Residency training is subjected to evolving society pressure of lower hourly work weeks imposed by external committees, labor laws, and increased public awareness of patient care quality. Although innovative measures for simulation training of surgery are appearing, there is also the realization that basic anatomy training should be re-enforced and cadaver dissection is of utmost importance for surgical techniques.In the development of new technology for implantable neurostimulatory electrodes for the management of phantom limb pain in amputee patients, a design of a cadaveric model has been developed with detailed steps for innovative transfascicular insertion of electrodes.

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This paper presents an implantable package aimed at hosting a bidirectional neural interface for neural prosthetic applications. The package has been conceived to minimize the invasivity for the patient, for this reason a cylindrical container with an outer diameter of 7 mm and a length of 21 mm has been designed. The package, realized in alumina (Al2O3), presents 32 hermetic feedthroughs located at the top and bottom base of the cylinder.

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