Robotic assistance during cochlear implantation: the rationale for consistent, controlled speed of electrode array insertion.

Cochlear implants (CI) have revolutionized the treatment of patients with severe to profound sensory hearing loss by providing a method of bypassing normal hearing to directly stimulate the auditory nerve. A further advance in the field has been the introduction of "hearing preservation" surgery, whereby the CI electrode array (EA) is carefully inserted to spare damage to the delicate anatomy and function of the cochlea. Preserving residual function of the inner ear allows patients to receive maximal benefit from the CI and to combine CI electric stimulation with acoustic hearing, offering improved postoperative speech, hearing, and quality of life outcomes.

A Steadier Hand: The First Human Clinical Trial of a Single-Use Robotic-Assisted Surgical Device for Cochlear Implant Electrode Array Insertion.

Objective: To evaluate the safety and utility of an investigational robotic-assisted cochlear implant insertion system.

Study Design: Prospective, single-arm, open-label study under abbreviated Investigational Device Exemption requirements.

Setting: All procedures were performed, and all data were collected, at a single tertiary referral center.

Comparative Analysis of Robotics-Assisted and Manual Insertions of Cochlear Implant Electrode Arrays.

Hypothesis: Robotics-assisted cochlear implant (CI) insertions will result in reduced intracochlear trauma when compared with manual, across multiple users.

Background: Whether intracochlear trauma and translocations are two factors that may contribute to significant variability in CI outcomes remains to be seen. To address this issue, we have developed a robotics-assisted insertion system designed to aid the surgeon in inserting electrode arrays with consistent speeds and reduced variability.

Development and Characterization of an Electrocochleography-Guided Robotics-Assisted Cochlear Implant Array Insertion System.

Objective: Electrocochleography (ECochG) is increasingly being used during cochlear implant (CI) surgery to detect and mitigate insertion-related intracochlear trauma, where a drop in ECochG signal has been shown to correlate with a decline in hearing outcomes. In this study, an ECochG-guided robotics-assisted CI insertion system was developed and characterized that provides controlled and consistent electrode array insertions while monitoring and adapting to real-time ECochG signals.

Study Design: Experimental research.

Zwitterionic Photografted Coatings of Cochlear Implant Biomaterials Reduce Friction and Insertion Forces.

Hypothesis: Application of photografted zwitterionic coatings to cochlear implant (CI) biomaterials will reduce friction and insertion forces.

Background: Strategies to minimize intracochlear trauma during implantation of an electrode array are critical to optimize outcomes including preservation of residual hearing. To this end, advances in thin-film zwitterionic hydrogel coatings on relevant biomaterials may show promise, in addition to the potential of these materials for decreasing the intracochlear foreign body response.

Evaluation of Insertion Forces and Cochlea Trauma Following Robotics-Assisted Cochlear Implant Electrode Array Insertion.

Hypothesis: The objective was to evaluate the effect of cochlear implant (CI) insertion technique on electrode insertion forces and intracochlear trauma. We hypothesize that robotics-assisted insertions will reduce insertion forces and intracochlear trauma compared with manual insertions.

Background: Variability in CI outcomes exists across patients, implant centers, surgeons, and electrode types.

Pilot Evaluation of Sheep as In Vivo Model for Cochlear Implantation.

Objectives: The rise in the use of cochlear implants (CIs) has continued to fuel research aimed at improving surgical approaches and the preservation of residual hearing. Current in vivo models involve small animals not suitable for evaluating full-sized CIs nor are prohibitively expensive nonhuman primates. The objective of this study was to develop and evaluate an in vivo model of cochlear implantation in sheep.

Degradable, antibiotic releasing poly(propylene fumarate)-based constructs for craniofacial space maintenance applications.

Space maintainers (SMs) used for craniofacial reconstruction function to preserve the void space created upon bone loss and promote soft tissue healing over the defect. Polymethylmethacrylate-based SMs present several drawbacks including implant exposure, secondary removal surgeries, and potential bacterial contamination during implantation. To address these issues, a novel composite material comprising poly(propylene fumarate) (PPF) with N-vinyl pyrrolidone (NVP) as the crosslinking agent, carboxymethylcellulose (CMC) hydrogel as a porogen, and antibiotic loaded poly(lactic-co-glycolic acid) (PLGA) microparticles as antibiotic carriers and porogen was fabricated.

Characterization of an injectable, degradable polymer for mechanical stabilization of mandibular fractures.

This study investigated the use of injectable poly(propylene fumarate) (PPF) formulations for mandibular fracture stabilization applications. A full factorial design with main effects analysis was employed to evaluate the effects of the PPF:N-vinyl pyrrolidone (NVP, crosslinking agent) ratio and dimethyl toluidine (DMT, accelerator) concentration on key physicochemical properties including setting time, maximum temperature, mechanical properties, sol fraction, and swelling ratio. Additionally, the effects of formulation crosslinking time on the mechanical and swelling properties were investigated.

Effects of antibiotic physicochemical properties on their release kinetics from biodegradable polymer microparticles.

Purpose: This study investigated the effects of the physicochemical properties of antibiotics on the morphology, loading efficiency, size, release kinetics, and antibiotic efficacy of loaded poly(DL-lactic-co-glycolic acid) (PLGA) microparticles (MPs) at different loading percentages.

Methods: Cefazolin, ciprofloxacin, clindamycin, colistin, doxycycline, and vancomycin were loaded at 10 and 20 wt% into PLGA MPs using a water-in-oil-in water double emulsion fabrication protocol. Microparticle morphology, size, loading efficiency, release kinetics, and antibiotic efficacy were assessed.

Use of porous space maintainers in staged mandibular reconstruction.

The success of mandibular reconstructions depends not only on restoring the form and function of lost bone but also on the preservation of the overlying soft tissue layer. In this case study, 5 porous polymethylmethacrylate space maintainers fabricated via patient-specific molds were implanted initially to maintain the vitality of the overlying oral mucosa during staged mandibular reconstructions. Three of the 5 patients healed well; the other 2 patients developed dehiscences, likely due to a thin layer of soft tissue overlying the implant.

Tissue response to composite hydrogels for vertical bone augmentation in the rat.

The objective of the present study was to develop a preclinical animal model for evaluating bone augmentation and to examine the level of bone augmentation induced by hydrogel composites. Design criteria outlined for the development of the animal model included rigid immobilization of bilateral implants apposed to the parietal bone of the rat, while avoiding the calvarial sutures. The animal model was evaluated through the implantation of hydrogel composites of oligo(poly(ethylene glycol) fumarate) (OPF) and gelatin microparticles releasing bone morphogenetic protein-2 (BMP-2).

Evaluation of antibiotic releasing porous polymethylmethacrylate space maintainers in an infected composite tissue defect model.

This study evaluated the in vitro and in vivo performance of antibiotic-releasing porous polymethylmethacrylate (PMMA)-based space maintainers comprising a gelatin hydrogel porogen and a poly(dl-lactic-co-glycolic acid) (PLGA) particulate carrier for antibiotic delivery. Colistin was released in vitro from either gelatin or PLGA microparticle loaded PMMA constructs, with gelatin-loaded constructs releasing colistin over approximately 7 days and PLGA microparticle-loaded constructs releasing colistin for up to 8 weeks. Three formulations with either burst release or extended release at different doses were tested in a rabbit mandibular defect inoculated with Acinetobacter baumannii (2×10(7) colony forming units ml(-1)).

Tungsten disulfide nanotubes reinforced biodegradable polymers for bone tissue engineering.

In this study, we have investigated the efficacy of inorganic nanotubes as reinforcing agents to improve the mechanical properties of poly(propylene fumarate) (PPF) composites as a function of nanomaterial loading concentration (0.01-0.2 wt.

Two-dimensional nanostructure-reinforced biodegradable polymeric nanocomposites for bone tissue engineering.

This study investigates the efficacy of two-dimensional (2D) carbon and inorganic nanostructures as reinforcing agents for cross-linked composites of the biodegradable and biocompatible polymer polypropylene fumarate (PPF) as a function of nanostructure concentration. PPF composites were reinforced using various 2D nanostructures: single- and multiwalled graphene oxide nanoribbons (SWGONRs, MWGONRs), graphene oxide nanoplatelets (GONPs), and molybdenum disulfide nanoplatelets (MSNPs) at 0.01-0.

Characterization of porous polymethylmethacrylate space maintainers for craniofacial reconstruction.

Porous polymethylmethacrylate (PMMA) has been used as an alloplastic bone substitute in the craniofacial complex, showing integration with the surrounding soft and hard tissue. This study investigated the physicochemical properties of curing and cured mixtures of a PMMA-based bone cement and a carboxymethylcellulose (CMC) gel porogen. Four formulations yielding porous PMMA of varied porosity were examined; specifically, two groups containing 30% (w/w) CMC gel in the mixture using a 7% (w/v) or 9% (w/v) stock CMC gel (30-7 and 30-9, respectively) and two groups containing 40% (w/w) CMC gel (40-7 and 40-9).

Development of a biodegradable bone cement for craniofacial applications.

This study investigated the formulation of a two-component biodegradable bone cement comprising the unsaturated linear polyester macromer poly(propylene fumarate) (PPF) and crosslinked PPF microparticles for use in craniofacial bone repair applications. A full factorial design was employed to evaluate the effects of formulation parameters such as particle weight percentage, particle size, and accelerator concentration on the setting and mechanical properties of crosslinked composites. It was found that the addition of crosslinked microparticles to PPF macromer significantly reduced the temperature rise upon crosslinking from 100.

In situ formation of porous space maintainers in a composite tissue defect.

Reconstruction of composite defects involving bone and soft tissue presents a significant clinical challenge. In the craniofacial complex, reconstruction of the soft and hard tissues is critical for both functional and aesthetic outcomes. Constructs for space maintenance provide a template for soft tissue regeneration, priming the wound bed for a definitive repair of the bone tissue with greater success.

Shaping the micromechanical behavior of multi-phase composites for bone tissue engineering.

Mechanical stiffness is a fundamental parameter in the rational design of composites for bone tissue engineering in that it affects both the mechanical stability and the osteo-regeneration process at the fracture site. A mathematical model is presented for predicting the effective Young's modulus (E) and shear modulus (G) of a multi-phase biocomposite as a function of the geometry, material properties and volume concentration of each individual phase. It is demonstrated that the shape of the reinforcing particles may dramatically affect the mechanical stiffness: E and G can be maximized by employing particles with large geometrical anisotropy, such as thin platelet-like or long fibrillar-like particles.