Development of Automated Tool for Electrode Array Insertion and its Study on Intracochlear Pressure

Cochlear implantation is the most successful approach for people with profound sensorineural hearing loss. Manual insertion of the electrode array may result in damaging the soft tissue structures and basilar membrane. An automated electrode array insertion device is reported to be less traumatic in cochlear implant surgery.

OBJECTIVES

The present work develops a simple, reliable, and compact device for automatically inserting the electrode array during cochlear implantation and test the device to observe intracochlear pressure during simulated electrode insertion.

METHODS

The device actuates the electrode array by a roller mechanism. For testing the automated device, a straight cochlea having the dimension of the scala tympani and a model electrode is developed using a 3D printer. A pressure sensor is utilized to observe the pressure change at different insertional conditions.

RESULTS

The electrode is inserted into a prototype cochlea at different speeds without any pause, and it is noticed that the pressure is increased with the depth of insertion of the electrode irrespective of the speed of electrode insertion. The rate of pressure change is observed to be increased exponentially with the speed of insertion.

CONCLUSION

At an insertion speed of 0.15 mm/s, the peak pressure is observed to be 133 Pa, which can be further evaluated in anatomical models for clinical scenarios.

LEVEL OF EVIDENCE

N/A Laryngoscope, 134:1388-1395, 2024.

An Experimental Study on the Rheological Behavior of Carbon Black-Boron Nitride Hybrid Nanofluids and Development of a New Correlation

Hybrid nanofluids, a new class of nanofluid has the ability to further enhance the thermo-physical properties by balancing the benefits of both kinds of nanomaterials as compared with nanofluids synthesized using only one kind of material. In this work, water-based nanofluids containing suspensions of carbon black (CB)-boron nitride (BN) (mass ratio = 50:50) nanoparticles are synthesized and studied for its rheological properties. The viscosity of CB-BN nanofluids are measured at temperatures between 30 °C-60 °C for volume concentrations 0.25 to 2 vol.%. The viscosity shows an increase with increasing particle concentration and decreases with temperature. A non-Newtonian nature with a dilatant behavior in the shear rate range of 5.4 s^-1 to 130 s^-1 is observed for all concentrations and temperatures. Also, it follows a power law model and its parameters, i.e., power index and consistency index are obtained by the curve fitting method. The non-Newtonian nature intensifies at low temperatures and concentrations. A new correlation is developed to predict the viscosity of CB-BN hybrid nanofluids.

The difference in the thermal conductivity of nanofluids measured by different methods and its rationalization

A suspension of particles below 100 nm in size, usually termed as nanofluid, often shows a notable enhancement in thermal conductivity, when measured by the transient hot-wire method. In contrast, when the conductivity of the same nanofluid is measured by the laser flash method, the enhancement reported is about one order of magnitude lower. This difference has been quantitatively resolved for the first time on the basis of the collision-mediated heat transfer model for nanofluids proposed earlier by our research group. Based on the continuum simulation coupled with stochastic analysis, the present theoretical prediction agrees well with the experimental observations from different measuring methods reported in the literature, and fully accounts for the different results from the two measuring methods mentioned above. This analysis also gives an indication that the nanofluids are unlikely to be effective for heat transfer in microchannels.