Implantation and long-term assessment of the stability and biocompatibility of a novel 98 channel suprachoroidal visual prosthesis in sheep.

Severe visual impairment can result from retinal degenerative diseases such as retinitis pigmentosa, which lead to photoreceptor cell death. These pathologies result in extensive neural and glial remodelling, with survival of excitable retinal neurons that can be electrically stimulated to elicit visual percepts and restore a form of useful vision. The Phoenix Bionic Eye is a fully implantable visual prosthesis, designed to stimulate the retina from the suprachoroidal space.

The common carotid artery provides significant pressure wave dampening in the young adult sheep.

Background: It has been established that the central elastic arteries of the mammalian circulation dampen the high pulse pressure emanating from the left ventricle, so that the pulsations in distal arterioles, such as in the cerebral circulation, are of lower amplitude than more centrally. However, the contribution of the common carotid artery (CCA) to protection of the cerebral microvasculature from high pulse pressure is not known, specifically to what extent viscoelastic energy dissipation in the arterial wall might contribute to the shock absorbing function of the large conduit arteries.

Methods: Young adult sheep (n = 6) were anaesthetised and their CCAs (n = 7) exposed.

Measurement of forces at the tip of a cochlear implant during insertion.

An optical fiber-based sensor has been developed to measure the forces at the tip of an electrode array during insertion into the cochlea. The sensor, utilizing optical fiber Bragg grating technology, was incorporated into a custom-designed Pt-banded electrode array for guinea pigs. In vivo experiments were undertaken in which forces at the tip of the array were measured in real time during the insertion.

Welding methods for joining thermoplastic polymers for the hermetic enclosure of medical devices.

New high performance polymers have been developed that challenge traditional encapsulation materials for permanent active medical implants. The gold standard for hermetic encapsulation for implants is a titanium enclosure which is sealed using laser welding. Polymers may be an alternative encapsulation material.

Implantation of the VentrAssist Implantable Rotary Blood Pump in sheep.

The VentrAssist Implantable Rotary Blood Pump (IRBP) is a hydrodynamically suspended, electromagnetically driven, centrifugal blood pump that provides continuous flow of up to 10 L/min at 3,000 rpm. In vivo studies in sheep were conducted to assess system design and performance. Surgery involved thoracotomy with subdiaphragmatic pump placement.

Evaluation of hemolysis in the VentrAssist implantable rotary blood pump.

The VentrAssist implantable rotary blood pump (IRBP) is an implantable centrifugal blood pump with a hydrodynamically suspended impeller; optimal efficiency requires small running clearances (70-300 microm). The effect of running clearance and polish on hemolysis was evaluated in vitro. Three different human blood suspensions were compared: phosphate buffered saline (PBS), plasma volume expander (Hemaccel), and whole blood.

Initial in vivo experience of the VentrAssist implantable rotary blood pump in sheep.

VentrAssist (VentrAssist Division, Ventracor Ltd., Chatswood, NSW, Australia) has developed an implantable centrifugal blood pump with an integrated rotor and impeller that is hydrodynamically suspended. Bench testing has been used to assess the performance of the pump under a broad range of operating conditions.