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

Autonomous Robotic Systems in Otolaryngology-Head and Neck Surgery

Robotic surgery is a growing field with increasing applications to patient care. With the rising use of artificial intelligence (AI), a new frontier emerges, allowing semiautonomous robotics. This article reviews the origins of robotic surgery and subsequent trials of automaticity in all fields. It then describes specific nascent robotic and semiautonomous surgical prototypes within the field of otolaryngology. Finally, broader systemic considerations are posited regarding the implementation of AI-driven robotics in surgery.

Metronome-guided cochlear implantation for slower and smoother insertions of lateral wall electrodes

INTRODUCTION

Achieving a slow and smooth electrode array insertion is paramount for preserving structural and functional integrity during cochlear implantation. This controlled study evaluates the efficacy of a metronome-guided insertion technique in enhancing the smoothness and speed of electrode array insertions.

METHODS

In a prospective cohort study, patients undergoing cochlear implant surgery between 2022 and 2023 with lateral wall electrode arrays were included. Metronome guidance was delivered through an acoustic signal via headphones during electrode array insertion in cochlear implantation and compared to a control group without metronome-guidance.

RESULTS

In total, 37 cases were evaluated, including 25 conventional insertions and 12 metronome-guided insertions. The results indicate that metronome-guided insertions were significantly slower (- 0.46 mm/s; p < 0.001) without extending the overall procedure time. This can be attributed to fewer paused sections observed in the metronome-guided technique. Moreover, metronome-guided insertions exhibited superior performance in terms of insertion smoothness and a reduced number of re-gripping events.

CONCLUSIONS

The findings support the recommendation for the systematic application of metronome guidance in the manual insertion of cochlear implant electrode arrays, emphasizing its potential to optimize surgical outcomes.

Innovative computed tomography based mapping of the surgical posterior tympanotomy: An exploratory study

Robotic devices have recently enhanced cochlear implantation by improving precision resulting in reduced intracochlear damage during electrode insertion. This study aimed to gain first insights into the expected dimensions of the cone-like workspace from the posterior tympanotomy towards the round window membrane. This retrospective chart review analyzed ten postoperative CT scans of adult patients who were implanted with a CI in the past ten years. The dimensions of the cone-like workspace were determined using four landmarks (P1-P4). In the anteroposterior range, P1 and P2 were defined on the edge of the bony layer over the facial nerve and chorda tympani nerve, respectively. In the inferosuperior range, P3 was defined on the bony edge of the incus buttress and P4 was obtained at a distance of 0.45 mm between the facial nerve and the chorda tympani nerve. After selecting the landmarks, the calculations of the dimensions of the surgical access space were done in a standardized coordinate system and presented using descriptive statistics. The cone-like space is limited by two maximal angles, α and β. The average angle α of 19.84 (±3.55) degrees defines the angle towards the round window membrane between P1 and P2. The second average angle β of 53.56 (±10.29) degrees defines the angle towards the round window membrane between P3 and P4. Based on the angles the mean anteroposterior range of 2.25 (±0.42) mm and mean inferosuperior range of 6.73 (±2.42) mm. The distance from the posterior tympanotomy to the round window membrane was estimated at 6.05 (±0.71) mm. These findings present data on the hypothetical maximum workspace in which a future robotically steered insertion tool can be positioned for an optimal automated electrode insertion. A larger sample size is necessary before generalizing these dimensions to a population. Further research including preoperative CT scans is needed for planning robotic-steered cochlear implantation.

Objective evaluation, using computed tomography, of round window access for cochlear implantation

OBJECTIVE

The aim of this study was to determine optimal radiological parameters for assessment of the round window approach in cochlear implantation surgery.

MATERIALS AND METHODS

Patients undergoing cochlear implantation at the Department of Otolaryngology in Szczecin, between 2015 and 2022 inclusive, were eligible for the study. Radiological assessments were performed according to eight parameters (seven proposed in the literature) and visibility clinical assessments were made intra-operatively on a scale of 1 to 5 (1 - not visible, 5 - fully visible). Visibility assessments of the round window niche (RWN) and round window membrane (RWM) allowed the difference (RWN minus RWM) to be used as a clinical assessment of the size of the overhang over the round window.

RESULTS

Computed tomography images of 57 ears from 52 patients were analyzed in terms of round window access. The study group included 26 females and 26 males, ranging in age from 1 year to 80 years, with a median age of 41 years. In clinical assessment, round window visibility was rated as 5, after removal of the bone overhang, in 69% of patients. Cochlear access through the round window was achieved in 39 (68%) cases, extended access through the round window in 13 (23%) cases and cochleostomy was performed in 5 (9%) cases. Statistically significant ordinal correlations with round-window access were found using one parameter from the literature (Chen_Angle) and from our proposal (RWM_prediction). From parameters describing the bone overhang of the round window, positive correlations (using Kendall rank tests) were found using parameters from the literature (Sarafraz_OH and Mehanna_OH).

CONCLUSIONS

Radiological measurements describing access to the round window which determine the angle based on the anatomy of the posterior wall of the auditory canal and the position of the facial nerve were found to be of the highest value.

CLINICAL RELEVANCE STATEMENT

In the future, the use of algorithms for computed tomography evaluation and robot-assisted surgery will require parameters for assessing round window access, for surgery planning and choice of electrode. The parameters proposed by various authors are summarized, allowing researchers to assess their usefulness in further clinical practice.

Recent advances in Otology: Current landscape and future direction

Hearing is an essential sensation, and its deterioration leads to a significant decrease in the quality of life. Thus, great efforts have been made by otologists to preserve and recover hearing. Our knowledge regarding the field of otology has progressed with advances in technology, and otologists have sought to develop novel approaches in the field of otologic surgery to achieve higher hearing recovery or preservation rates. This requires knowledge regarding the anatomy of the temporal bone and the physiology of hearing. Basic research in the field of otology has progressed with advances in molecular biology and genetics. This review summarizes the current views and recent advances in the field of otology and otologic surgery, especially from the viewpoint of young Japanese clinician-scientists, and presents the perspectives and future directions for several topics in the field of otology. This review will aid next-generation researchers in understanding the recent advances and future challenges in the field of otology.

Uncovering Vulnerable Phases in Cochlear Implant Electrode Array Insertion: Insights from an In Vitro Model

OBJECTIVES

The aim of this study is to improve our understanding of the mechanics involved in the insertion of lateral wall cochlear implant electrode arrays.

DESIGN

A series of 30 insertion experiments were conducted by three experienced surgeons. The experiments were carried out in a previously validated artificial temporal bone model according to established soft surgery guidelines. The use of an in vitro setup enabled us to comprehensively evaluate relevant parameters, such as insertion force, intracochlear pressure, and exact electrode array position in a controlled and repeatable environment.

RESULTS

Our findings reveal that strong intracochlear pressure transients are more frequently caused during the second half of the insertion, and that regrasping the electrode array is a significant factor in this phenomenon. For choosing an optimal insertion speed, we show that it is crucial to balance slow movement to limit intracochlear stress with short duration to limit tremor-induced pressure spikes, challenging the common assumption that a slower insertion is inherently better. Furthermore, we found that intracochlear stress is affected by the order of execution of postinsertion steps, namely sealing the round window and posterior tympanotomy with autologous tissue and routing of the excess cable into the mastoid cavity. Finally, surgeons' subjective estimates of physical parameters such as speed, smoothness, and resistance did not correlate with objectively assessed measures, highlighting that a thorough understanding of intracochlear mechanics is essential for an atraumatic implantation.

CONCLUSION

The results presented in this article allow us to formulate evidence-based surgical recommendations that may ultimately help to improve surgical outcome and hearing preservation in cochlear implant patients.

Combining Intraoperative Electrocochleography with Robotics-Assisted Electrode Array Insertion

OBJECTIVE

To describe the use of robotics-assisted electrode array (EA) insertion combined with intraoperative electrocochleography (ECochG) in hearing preservation cochlear implant surgery.

STUDY DESIGN

Prospective, single-arm, open-label study.

SETTING

All procedures and data collection were performed at a single tertiary referral center.

PATIENTS

Twenty-one postlingually deaf adult subjects meeting Food and Drug Administration indication criteria for cochlear implantation with residual acoustic hearing defined as thresholds no worse than 65 dB at 125, 250, and 500 Hz.

INTERVENTION

All patients underwent standard-of-care unilateral cochlear implant surgery using a single-use robotics-assisted EA insertion device and concurrent intraoperative ECochG.

MAIN OUTCOME MEASURES

Postoperative pure-tone average over 125, 250, and 500 Hz measured at initial activation and subsequent intervals up to 1 year afterward.

RESULTS

Twenty-two EAs were implanted with a single-use robotics-assisted insertion device and simultaneous intraoperative ECochG. Fine control over robotic insertion kinetics could be applied in response to changes in ECochG signal. Patients had stable pure-tone averages after activation with normal impedance and neural telemetry responses.

CONCLUSIONS

Combining robotics-assisted EA insertion with intraoperative ECochG is a feasible technique when performing hearing preservation implant surgery. This combined approach may provide the surgeon a means to overcome the limitations of manual insertion and respond to cochlear feedback in real-time.

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. However, under the current paradigm of implant surgery, where EAs are inserted by hand, the cochlea cannot be reliably spared from damage. Robotics-assisted EA insertion is an emerging technology that may overcome fundamental human kinetic limitations that prevent consistency in achieving steady and slow EA insertion. This review begins by describing the relationship between EA insertion speed and generation of intracochlear forces and pressures. The various mechanisms by which these intracochlear forces can damage the cochlea and lead to worsened postoperative outcomes are discussed. The constraints of manual insertion technique are compared to robotics-assisted methods, followed by an overview of the current and future state of robotics-assisted EA insertion.

Evaluation of Real-Time Intracochlear Electrocochleography for Guiding Cochlear Implant Electrode Array Position

This study evaluates intracochlear electrocochleography (ECochG) for real-time monitoring during cochlear implantation. One aim tested whether adjusting the recording electrode site would help differentiate between atraumatic and traumatic ECochG amplitude decrements. A second aim assessed whether associations between ECochG amplitude decrements and post-operative hearing loss were weaker when considering hearing sensitivity at the ECochG stimulus frequency compared to a broader frequency range. Eleven adult cochlear implant recipients who were candidates for electro-acoustic stimulation participated. Single-frequency (500-Hz) ECochG was performed during cochlear implantation; the amplitude of the first harmonic of the difference waveform was considered. Post-operative hearing preservation at 500 Hz ranged from 0 to 94%. The expected relationship between ECochG amplitude decrements and hearing preservation was observed, though the trend was not statistically significant, and predictions were grossly inaccurate for two participants. Associations did not improve when considering alternative recording sites or hearing sensitivity two octaves above the ECochG stimulus frequency. Intracochlear location of a moving recording electrode is a known confound to real-time interpretation of ECochG amplitude fluctuations, which was illustrated by the strength of the correlation with ECochG amplitude decrements. Multiple factors contribute to ECochG amplitude patterns and to hearing preservation; these results highlight the confounding influence of intracochlear recording electrode location on the ECochG.