Instrument flight to the inner ear

More than 40 years of cochlear implant research: A bibliometric analysis

OBJECTIVES

Cochlear implantation is the most effective treatment for patients with severe-to-profound sensorineural hearing loss. Much scientific work has been published since their inception. There is a need for a critical reflection on how and what we publish on cochlear implantation.

METHODS

All Science Citation Index Expanded featured articles between 1980 and 2022 with the word 'cochlear implants' or 'cochlear implantation' were collected from the Web of Science database. Separate characteristics, such as the publication dates, the journals, the number of citations, the countries of origin, the authors, the institutions and co-occurring keywords, were assessed.

RESULTS

13,934 articles were included in the data analysis. The journals of of Otology and Neurotology, Ear and Hearing and of Pediatric Otorhinolaryngology represent the top three most publishing journals. Hannover Medical School, the University of Melbourne and the University of Northern Iowa represent the top three most publishing institutions.

DISCUSSION

The amount of scientific publications on cochlear implant technology has increased for the last 40 years. Besides the focus on speech perception, the research landscape on cochlear implantation is broad and diverse. The number of countries and institutions contributing to these publications is limited.

CONCLUSION

This bibliometric analysis serves as a quantitative overview of the research landscape on cochlear implantation.

Touchless Artificial Perception beyond Fingertip Probing

Touchless perception technology allows us to acquire information beyond the contact interfaces, making it ideal for scenarios where physical engagements are not possible. Unlike tactile devices, which have so far achieved impressive results, touchless strategies are fascinating yet underdeveloped. We envisage that touchless technologies could be powerful supplements to current haptics. In this Perspective, we include emerging touchless electronics, aiming to provide a broader and comprehensive picture toward artificial perceptual realm. We overview popular touchless protocols, sketch what could be detected by touchless probing, and summarize their latest spectacular achievements. In addition, we present the promises and challenges posed by touchless technologies and discuss possible directions for their future deployments.

Thermal ablation with configurable shapes: a comprehensive, automated model for bespoke tumor treatment

BACKGROUND

Malignant tumors routinely present with irregular shapes and complex configurations. The lack of customization to individual tumor shapes and standardization of procedures limits the success and application of thermal ablation.

METHODS

We introduced an automated treatment model consisting of (i) trajectory and ablation profile planning, (ii) ablation probe insertion, (iii) dynamic energy delivery (including robotically driven control of the energy source power and location over time, according to a treatment plan bespoke to the tumor shape), and (iv) quantitative ablation margin verification. We used a microwave ablation system and a liver phantom (acrylamide polymer with a thermochromic ink) to mimic coagulation and measure the ablation volume. We estimated the ablation width as a function of power and velocity following a probabilistic model. Four representative shapes of liver tumors < 5 cm were selected from two publicly available databases. The ablated specimens were cut along the ablation probe axis and photographed. The shape of the ablated volume was extracted using a color-based segmentation method.

RESULTS

The uncertainty (standard deviation) of the ablation width increased with increasing power by ± 0.03 mm (95% credible interval [0.02, 0.043]) per watt increase in power and by ± 0.85 mm (95% credible interval [0, 2.5]) per mm/s increase in velocity. Continuous ablation along a straight-line trajectory resulted in elongated rotationally symmetric ablation shapes. Simultaneous regulation of the power and/or translation velocity allowed to modulate the ablation width at specific locations.

CONCLUSIONS

This study offers the proof-of-principle of the dynamic energy delivery system using ablation shapes from clinical cases of malignant liver tumors.

RELEVANCE STATEMENT

The proposed automated treatment model could favor the customization and standardization of thermal ablation for complex tumor shapes.

KEY POINTS

• Current thermal ablation systems are limited to ellipsoidal or spherical shapes. • Dynamic energy delivery produces elongated rotationally symmetric ablation shapes with varying widths. • For complex tumor shapes, multiple customized ablation shapes could be combined.

Automatic cochlear multimodal 3D image segmentation and analysis using atlas-model-based method

Objectives: To propose an automated fast cochlear segmentation, length, and volume estimation method from clinical 3D multimodal images which has a potential role in the choice of cochlear implant type, surgery planning, and robotic surgeries.

Methods: Two datasets from different countries were used. These datasets include 219 clinical 3D images of cochlea from 3 modalities: CT, CBCT, and MR. The datasets include different ages, genders, and types of cochlear implants. We propose an atlas-model-based method for cochlear segmentation and measurement based on high-resolution μCT model and A-value. The method was evaluated using 3D landmarks located by two experts.

Results: The average error was 0.61 ± 0.22 mm and the average time required to process an image was 5.21 ± 0.93 seconds (P<0.001). The volume of the cochlea ranged from 73.96 mm3 to 106.97 mm3 , the cochlear length ranged from 36.69 to 45.91 mm at the lateral wall and from 29.12 to 39.05 mm at the organ of Corti.

Discussion: We propose a method that produces nine different automated measurements of the cochlea: volume of scala tympani, volume of scala vestibuli, central lengths of the two scalae, the scala tympani lateral wall length, and the organ of Corti length in addition to three measurements related to A-value.

Conclusion: This automatic cochlear image segmentation and analysis method can help clinician process multimodal cochlear images in approximately 5 seconds using a simple computer. The proposed method is publicly available for free download as an extension for 3D Slicer software.

Audiological outcomes of robot-assisted cochlear implant surgery

PURPOSE

The main objective of this study is to evaluate the short-term and long-term audiological outcomes in patients who underwent cochlear implantation with a robot-assisted system to enable access to the cochlea, and to compare outcomes with a matched control group of patients who underwent cochlear implantation with conventional access to the cochlea.

METHODS

In total, 23 patients were implanted by robot-assisted cochlear implant surgery (RACIS). To evaluate the effectiveness of robotic surgery in terms of audiological outcomes, a statistically balanced control group of conventionally implanted patients was created. Minimal outcome measures (MOM), consisting of pure-tone audiometry, speech understanding in quiet and speech understanding in noise were performed pre-operatively and at 3 months, 6 months, 12 months and 2 years post-activation of the audioprocessor.

RESULTS

There was no statistically significant difference in pure-tone audiometry, speech perception in quiet and speech perception in noise between robotically implanted and conventionally implanted patients pre-operatively, 3 months, 6 months, 12 months and 2 years post-activation. A significant improvement in pure-tone hearing thresholds, speech understanding in quiet and speech understanding in noise with the cochlear implant has been quantified as of the first measurements at 3 months and this significant improvement remained stable over a time period of 2 years for HEARO implanted patients.

CONCLUSION

Clinical outcomes in robot-assisted cochlear implant surgery are comparable to conventional cochlear implantation. CLINICALTRAILS.

GOV TRAIL REGISTRATION NUMBERS

NCT03746613 (date of registration: 19/11/2018), NCT04102215 (date of registration: 25/09/2019).

True keyhole cochlear implant surgery

INTRODUCTION

Minimal invasive Robotic Assisted Cochlear Implant Surgery (RACIS) is a keyhole surgery by definition. It is therefore not possible to visualize the electrode array during insertion in the scala tympani. Hitherto, surgeons visualised the round window via the external auditory canal by folding over the tympanic membrane. However, the opening of a tympanomeatal flap is not minimal invasive and is especially in conventional cochlear implantation surgery not even necessary. Here we prove that image guided and robot assisted surgery can also allow correct electrode array insertion without opening the tympanomeatal flap.

AIM

The aim is to report the first experience of robotic cochlear implantation surgery fully based on image guided surgery and without the opening of a tympanomeatal flap for electrode array insertion.

INTERVENTION

RACIS with a straight flexible lateral wall electrode.

PRIMARY OUTCOME MEASUREMENTS

Electrode cochlear insertion depth with RACIS and autonomous inner ear access with full electrode insertion of a flexible lateral wall electrode array.

SECONDARY OUTCOME MEASUREMENTS

The audiological outcome in terms of mean hearing thresholds.

CONCLUSION

After a series of 33 cases and after fine-tuning the insertion angles and yet another new version of planning software to depict the round window approach, a new clinical routine for inserting electrodes fully based on image guided surgery without opening a tympanomeatal flap was developed in robotic-assisted cochlear implant surgery.

Application of UNETR for automatic cochlear segmentation in temporal bone CTs

OBJECTIVE

To investigate the feasibility of a deep learning method based on a UNETR model for fully automatic segmentation of the cochlea in temporal bone CT images.

METHODS

The normal temporal bone CTs of 77 patients were used in 3D U-Net and UNETR model automatic cochlear segmentation. Tests were performed on two types of CT datasets and cochlear deformity datasets.

RESULTS

Through training the UNETR model, when batch_size=1, the Dice coefficient of the normal cochlear test set was 0.92, which was higher than that of the 3D U-Net model; on the GE 256 CT, SE-DS CT and Cochlear Deformity CT dataset tests, the Dice coefficients were 0.91, 0.93, 0 93, respectively.

CONCLUSION

According to the anatomical characteristics of the temporal bone, the use of the UNETR model can achieve fully automatic segmentation of the cochlea and obtain an accuracy close to manual segmentation. This method is feasible and has high accuracy.

Evaluation of a Less Invasive Cochlear Implant Surgery in OPA1 Mutations Provoking Deafblindness

Cochlear implantation (CI) for deafblindness may have more impact than for non-syndromic hearing loss. Deafblind patients have a double handicap in a society that is more and more empowered by fast communication. CI is a remedy for deafness, but requires revision surgery every 20 to 25 years, and thus placement should be minimally invasive. Furthermore, failed reimplantation surgery will have more impact on a deafblind person. In this context, we assessed the safety of minimally invasive robotically assisted cochlear implant surgery (RACIS) for the first time in a deafblind patient. Standard pure tone audiometry and speech audiometry were performed in a patient with deafblindness as part of this robotic-assisted CI study before and after surgery. This patient, with an optic atrophy 1 (OPA1) (OMIM#165500) mutation consented to RACIS for the second (contralateral) CI. The applicability and safety of RACIS were evaluated as well as her subjective opinion on her disability. RACIS was uneventful with successful surgical and auditory outcomes in this case of deafblindness due to the OPA1 mutation. RACIS appears to be a safe and beneficial intervention to increase communication skills in the cases of deafblindness due to an OPA1 mutation. The use of RACIS use should be widespread in deafblindness as it minimizes surgical trauma and possible failures.

Advances in Robot-Assisted Surgery for Facial Bone Contouring Surgery

Since our team reported the application of robot-assisted surgery in facial contouring surgery in 2020, further clinical trials with large samples have been conducted. This paper will report the interim results of a single-center, large-sample randomized controlled trial of the first robot developed by our team for facial contouring surgery. Meanwhile, this research field will be systematically reviewed and prospected.

Split electrodes for electrical-conductivity-based tissue discrimination

This work presents a method to minimize the inadvertent cutting of tissues in surgeries involving bone drilling. We present electrical impedance measurements as an assistive technology to image-guided surgery to achieve online guidance. Proposed concept is to identify and localize the landmarks via impedance measurements and then use this information to superimpose the estimated drilling trajectory on the offline maps obtained by pre-operative imaging. To this end., we propose an asymmetric electrode geometry., split electrodes., capable of distinguishing impedance variations as a function of rotation angle. The feasibility of the proposed approach is verified with numerical analysis. A probe with stainless steel electrodes has been fabricated and tested with a technical phantom. Although the results are impacted by a non-ideality in the phantom., we could show that the variation of impedance as a function of rotation angle can be used to localize the regions with different impedivities. Clinical Relevance- Presented approach may be used to minimize the inadvertent cutting of tissues in surgeries involving bone drilling.

Assessment of Robot-Assisted Mandibular Contouring Surgery in Comparison With Traditional Surgery: A Prospective, Single-Center, Randomized Controlled Trial

BACKGROUND

Few clinical studies on robot-assisted surgery (RAS) for mandibular contouring have been reported.

OBJECTIVES

The aim of this study was to follow the long-term effectiveness and safety of RAS for craniofacial bone surgery.

METHODS

This small-sample, early-phase, prospective, randomized controlled study included patients diagnosed with mandibular deformity requiring mandibular contouring surgery. Patients of both genders aged 18 to 30 years without complicated craniofacial repair defects were enrolled and randomly assigned in a 1:1 ratio by a permuted-block randomized assignments list generated by the study statistician. The primary outcomes were the positioning accuracy and accuracy of the osteotomy plane angle 1 week after surgery. Surgical auxiliary measurement index, patient satisfaction scale, surgical pain scale, perioperative period, and complications at 1 week, 1 month, and 6 months after surgery were also analyzed.

RESULTS

One patient was lost to follow-up, resulting in a total of 14 patients in the traditional surgery group and 15 in the robot-assisted group (mean [standard deviation] age, 22.65 [3.60] years). Among the primary outcomes, there was a significant difference in the positioning accuracy (2.91 mm vs 1.65 mm; P < 0.01) and angle accuracy (13.26º vs 4.85º; P < 0.01) between the 2 groups. Secondary outcomes did not significantly differ.

CONCLUSIONS

Compared to traditional surgery, robot-assisted mandibular contouring surgery showed improved precision in bone shaving, as well as higher safety.

LEVEL OF EVIDENCE: 2

First Study in Men Evaluating a Surgical Robotic Tool Providing Autonomous Inner Ear Access for Cochlear Implantation

Image-guided and robot-assisted surgeries have found their applications in skullbase surgery. Technological improvements in terms of accuracy also opened new opportunities for robotically-assisted cochlear implantation surgery (RACIS). The HEARO^® robotic system is an otological next-generation surgical robot to assist the surgeon. It first provides software-defined spatial boundaries for orientation and reference information to anatomical structures during otological and neurosurgical procedures. Second, it executes a preplanned drill trajectory through the temporal bone. Here, we report how safe the HEARO procedure can provide an autonomous minimally invasive inner ear access and the efficiency of this access to subsequently insert the electrode array during cochlear implantation. In 22 out of 25 included patients, the surgeon was able to complete the HEARO^® procedure. The dedicated planning software (OTOPLAN^®) allowed the surgeon to reconstruct a three-dimensional representation of all the relevant anatomical structures, designate the target on the cochlea, i.e., the round window, and plan the safest trajectory to reach it. This trajectory accommodated the safety distance to the critical structures while minimizing the insertion angles. A minimal distance of 0.4 and 0.3 mm was planned to facial nerve and chorda tympani, respectively. Intraoperative cone-beam CT supported safe passage for the 22 HEARO^® procedures. The intraoperative accuracy analysis reported the following mean errors: 0.182 mm to target, 0.117 mm to facial nerve, and 0.107 mm to chorda tympani. This study demonstrates that microsurgical robotic technology can be used in different anatomical variations, even including a case of inner ear anomalies, with the geometrically correct keyhole to access to the inner ear. Future perspectives in RACIS may focus on improving intraoperative imaging, automated segmentation and trajectory, robotic insertion with controlled speed, and haptic feedback. This study [Experimental Antwerp robotic research otological surgery (EAR2OS) and Antwerp Robotic cochlear implantation (25 refers to 25 cases) (ARCI25)] was registered at clinicalTrials.gov under identifier NCT03746613 and NCT04102215.

Image-Based Planning of Minimally Traumatic Inner Ear Access for Robotic Cochlear Implantation

Objective: During robotic cochlear implantation, an image-guided robotic system provides keyhole access to the scala tympani of the cochlea to allow insertion of the cochlear implant array. To standardize minimally traumatic robotic access to the cochlea, additional hard and soft constraints for inner ear access were proposed during trajectory planning. This extension of the planning strategy aims to provide a trajectory that preserves the anatomical and functional integrity of critical intra-cochlear structures during robotic execution and allows implantation with minimal insertion angles and risk of scala deviation.

Methods: The OpenEar dataset consists of a library with eight three-dimensional models of the human temporal bone based on computed tomography and micro-slicing. Soft constraints for inner ear access planning were introduced that aim to minimize the angle of cochlear approach, minimize the risk of scala deviation and maximize the distance to critical intra-cochlear structures such as the osseous spiral lamina. For all cases, a solution space of Pareto-optimal trajectories to the round window was generated. The trajectories satisfy the hard constraints, specifically the anatomical safety margins, and optimize the aforementioned soft constraints. With user-defined priorities, a trajectory was parameterized and analyzed in a virtual surgical procedure.

Results: In seven out of eight cases, a solution space was found with the trajectories safely passing through the facial recess. The solution space was Pareto-optimal with respect to the soft constraints of the inner ear access. In one case, the facial recess was too narrow to plan a trajectory that would pass the nerves at a sufficient distance with the intended drill diameter. With the soft constraints introduced, the optimal target region was determined to be in the antero-inferior region of the round window membrane.

Conclusion: A trend could be identified that a position between the antero-inferior border and the center of the round window membrane appears to be a favorable target position for cochlear tunnel-based access through the facial recess. The planning concept presented and the results obtained therewith have implications for planning strategies for robotic surgical procedures to the inner ear that aim for minimally traumatic cochlear access and electrode array implantation.

Robotic Milling of Electrode Lead Channels During Cochlear Implantation in an ex-vivo Model

Objective: Robotic cochlear implantation is an emerging surgical technique for patients with sensorineural hearing loss. Access to the middle and inner ear is provided through a small-diameter hole created by a robotic drilling process without a mastoidectomy. Using the same image-guided robotic system, we propose an electrode lead management technique using robotic milling that replaces the standard process of stowing excess electrode lead in the mastoidectomy cavity. Before accessing the middle ear, an electrode channel is milled robotically based on intraoperative planning. The goal is to further standardize cochlear implantation, minimize the risk of iatrogenic intracochlear damage, and to create optimal conditions for a long implant life through protection from external trauma and immobilization in a slight press fit to prevent mechanical fatigue and electrode migrations.

Methods: The proposed workflow was executed on 12 ex-vivo temporal bones and evaluated for safety and efficacy. For safety, the difference between planned and resulting channels were measured postoperatively in micro-computed tomography, and the length outside the planned safety margin of 1.0 mm was determined. For efficacy, the channel width and depth were measured to assess the press fit immobilization and the protection from external trauma, respectively.

Results: All 12 cases were completed with successful electrode fixations after cochlear insertions. The milled channels stayed within the planned safety margins and the probability of their violation was lower than one in 10,000 patients. Maximal deviations in lateral and depth directions of 0.35 and 0.29 mm were measured, respectively. The channels could be milled with a width that immobilized the electrode leads. The average channel depth was 2.20 mm, while the planned channel depth was 2.30 mm. The shallowest channel depth was 1.82 mm, still deep enough to contain the full 1.30 mm diameter of the electrode used for the experiments.

Conclusion: This study proposes a robotic electrode lead management and fixation technique and verified its safety and efficacy in an ex-vivo study. The method of image-guided robotic bone removal presented here with average errors of 0.2 mm and maximal errors below 0.5 mm could be used for a variety of other otologic surgical procedures.

Fusion of Technology in Cochlear Implantation Surgery: Investigation of Fluoroscopically Assisted Robotic Electrode Insertion

The HEARO cochlear implantation surgery aims to replace the conventional wide mastoidectomy approach with a minimally invasive direct cochlear access. The main advantage of the HEARO access would be that the trajectory accommodates the optimal and individualized insertion parameters such as type of cochlear access and trajectory angles into the cochlea. To investigate the quality of electrode insertion with the HEARO procedure, the insertion process was inspected under fluoroscopy in 16 human cadaver temporal bones. Prior to the insertion, the robotic middle and inner ear access were performed through the HEARO procedures. The status of the insertion was analyzed on the post-operative image with Siemens Artis Pheno (Siemens AG, Munich, Germany). The completion of the full HEARO procedure, including the robotic inner ear access and fluoroscopy electrode insertion, was possible in all 16 cases. It was possible to insert the electrode in all 16 cases through the drilled tunnel. However, one case in which the full cochlea was not visible on the post-operative image for analysis was excluded. The post-operative analysis of the electrode insertion showed an average insertion angle of 507°, which is equivalent to 1.4 turns of the cochlea, and minimal and maximal insertion angles were recorded as 373° (1 cochlear turn) and 645° (1.8 cochlear turn), respectively. The fluoroscopy inspection indicated no sign of complications during the insertion.

Freehand Stereotactic Image-Guidance Tailored to Neurotologic Surgery

Hypothesis: The use of freehand stereotactic image-guidance with a target registration error (TRE) of μ_TRE + 3σ_TRE < 0.5 mm for navigating surgical instruments during neurotologic surgery is safe and useful. Background: Neurotologic microsurgery requires work at the limits of human visual and tactile capabilities. Anatomy localization comes at the expense of invasiveness caused by exposing structures and using them as orientation landmarks. In the absence of more-precise and less-invasive anatomy localization alternatives, surgery poses considerable risks of iatrogenic injury and sub-optimal treatment. There exists an unmet clinical need for an accurate, precise, and minimally-invasive means for anatomy localization and instrument navigation during neurotologic surgery. Freehand stereotactic image-guidance constitutes a solution to this. While the technology is routinely used in medical fields such as neurosurgery and rhinology, to date, it is not used for neurotologic surgery due to insufficient accuracy of clinically available systems. Materials and Methods: A freehand stereotactic image-guidance system tailored to the needs of neurotologic surgery-most importantly sub-half-millimeter accuracy-was developed. Its TRE was assessed preclinically using a task-specific phantom. A pilot clinical trial targeting N = 20 study participants was conducted (ClinicalTrials.gov ID: NCT03852329) to validate the accuracy and usefulness of the developed system. Clinically, objective assessment of the TRE is impossible because establishing a sufficiently accurate ground-truth is impossible. A method was used to validate accuracy and usefulness based on intersubjectivity assessment of surgeon ratings of corresponding image-pairs from the microscope/endoscope and the image-guidance system. Results: During the preclinical accuracy assessment the TRE was measured as 0.120 ± 0.05 mm (max: 0.27 mm, μ_TRE + 3σ_TRE = 0.27 mm, N = 310). Due to the COVID-19 pandemic, the study was terminated early after N = 3 participants. During an endoscopic cholesteatoma removal, a microscopic facial nerve schwannoma removal, and a microscopic revision cochlear implantation, N = 75 accuracy and usefulness ratings were collected from five surgeons each grading 15 image-pairs. On a scale from 1 (worst rating) to 5 (best rating), the median (interquartile range) accuracy and usefulness ratings were assessed as 5 (4-5) and 4 (4-5) respectively. Conclusion: Navigating surgery in the tympanomastoid compartment and potentially in the lateral skull base with sufficiently accurate freehand stereotactic image-guidance (μ_TRE + 3σ_TRE < 0.5 mm) is feasible, safe, and useful. Clinical Trial Registration: www.ClinicalTrials.gov, identifier: NCT03852329.

In Silico Assessment of Safety and Efficacy of Screw Placement for Pediatric Image-Guided Otologic Surgery

Introduction: Current high-accuracy image-guided systems for otologic surgery use fiducial screws for patient-to-image registration. Thus far, these systems have only been used in adults, and the safety and efficacy of the fiducial screw placement has not yet been investigated in the pediatric population.

Materials and Methods: In a retrospective study, CT image data of the temporal region from 11 subjects meeting inclusion criteria (8–48 months at the time of surgery) were selected, resulting in n = 20 sides. These datasets were investigated with respect to screw stability efficacy in terms of the cortical layer thickness, and safety in terms of the distance of potential fiducial screws to the dura mater or venous sinuses. All of these results are presented as distributions, thickness color maps, and with descriptive statistics. Seven regions within the temporal bone were analyzed individually. In addition, four fiducial screws per case with 4 mm thread-length were placed in an additively manufactured model according to the guidelines for robotic cochlear implantation surgery. For all these screws, the minimal distance to the dura mater or venous sinuses was measured, or if applicable how much they penetrated these structures.

Results: The cortical layer has been found to be mostly between 0.7–3.3 mm thick (from the 5^th to the 95^th percentile), while even thinner areas exist. The distance from the surface of the temporal bone to the dura mater or the venous sinuses varied considerably between the subjects and ranged mostly from 1.1–9.3 mm (from the 5^th to the 95^th percentile). From all 80 placed fiducial screws of 4 mm thread length in the pediatric subject younger than two years old, 22 touched or penetrated either the dura or the sigmoid sinus. The best regions for fiducial placement would be the mastoid area and along the petrous pyramid in terms of safety. In terms of efficacy, the parietal followed by the petrous pyramid, and retrosigmoid regions are most suited.

Conclusion: The current fiducial screws and the screw placement guidelines for adults are insufficiently safe or effective for pediatric patients.

Robotic Cochlear Implant Surgery: Imaging-Based Evaluation of Feasibility in Clinical Routine

Background: Robotic surgery has been proposed in various surgical fields to reduce recovery time, scarring, and to improve patients' outcomes. Such innovations are ever-growing and have now reached the field of cochlear implantation. To implement robotic ear surgery in routine, it is of interest if preoperative planning of a safe trajectory to the middle ear is possible with clinically available image data.

Methods: We evaluated the feasibility of robotic cochlear implant surgery in 50 patients (100 ears) scheduled for routine cochlear implant procedures based on clinically available imaging. The primary objective was to assess if available high-resolution computed tomography or cone beam tomography imaging is sufficient for planning a trajectory by an otological software. Secondary objectives were to assess the feasibility of cochlear implant surgery with a drill bit diameter of 1.8 mm, which is the currently used as a standard drill bit. Furthermore, it was evaluated if feasibility of robotic surgery could be increased when using smaller drill bit sizes. Cochlear and trajectory parameters of successfully planned ears were collected. Measurements were carried out by two observers and the interrater reliability was assessed using Cohen's Kappa.

Results: Under the prerequisite of the available image data being sufficient for the planning of the procedure, up to two thirds of ears were eligible for robotic cochlear implant surgery with the standard drill bit size of 1.8 mm. The main reason for inability to plan the keyhole access was insufficient image resolution causing anatomical landmarks not being accurately identified. Although currently not applicable in robotic cochlear implantation, narrower drill bit sizes ranging from 1.0 to 1.7 mm in diameter could increase feasibility up to 100%. The interrater agreement between the two observers was good for this data set.

Discussion: For robotic cochlear implant surgery, imaging with sufficient resolution is essential for preoperative assessment. A slice thickness of <0.3 mm is necessary for trajectory planning. This can be achieved by using digital volume tomography while radiation exposure can be kept to a minimum. Furthermore, surgeons who use the software tool, should be trained on a regular basis in order to achieve planning consistency.

Quantitative Analysis of Temporal Bone Density and Thickness for Robotic Ear Surgery

Background and Objective: Quantitative assessment of bone density and thickness in computed-tomography images offers great potential for preoperative planning procedures in robotic ear surgery. Methods: We retrospectively analyzed computed-tomography scans of subjects undergoing cochlear implantation (N = 39). In addition, scans of Thiel-fixated ex-vivo specimens were analyzed (N = 15). To estimate bone mineral density, quantitative computed-tomography data were obtained using a calibration phantom. The temporal bone thickness and cortical bone density were systematically assessed at retroauricular positions using an automated algorithm referenced by an anatomy-based coordinate system. Two indices are proposed to include information of bone density and thickness for the preoperative assessment of safe screw positions (Screw Implantation Safety Index, SISI) and mass distribution (Column Density Index, CODI). Linear mixed-effects models were used to assess the effects of age, gender, ear side and position on bone thickness, cortical bone density and the distribution of the indices. Results: Age, gender, and ear side only had negligible effects on temporal bone thickness and cortical bone density. The average radiodensity of cortical bone was 1,511 Hounsfield units, corresponding to a bone mineral density of 1,145 mg HA/cm³. Temporal bone thickness and cortical bone density depend on the distance from Henle's spine in posterior direction. Moreover, safe screw placement locations can be identified by computation of the SISI distribution. A local maximum in mass distribution was observed posteriorly to the supramastoid crest. Conclusions: We provide quantitative information about temporal bone density and thickness for applications in robotic and computer-assisted ear surgery. The proposed preoperative indices (SISI and CODI) can be applied to patient-specific cases to identify optimal regions with respect to bone density and thickness for safe screw placement and effective implant positioning.

Precise laminae segmentation based on neural network for robot-assisted decompressive laminectomy

BACKGROUND AND OBJECTIVE

The decompressive laminectomy is one of the most common operations to treat lumbar spinal stenosis by removing the laminae above the spinal nerve. Recently, an increasing number of robots are deployed during the surgical process to reduce the burden on surgeons and to reduce complications. However, for the robot-assisted decompressive laminectomy, an accurate 3D model of laminae from a CT image is highly desired. The purpose of this paper is to precisely segment the laminae with fewer calculations.

METHODS

We propose a two-stage neural network SegRe-Net. In the first stage, the entire intraoperative CT image is inputted to acquire the coarse segmentation of vertebrae with low resolution and the probability map of the laminar centers. The second stage is trained to refine the segmentation of laminae.

RESULTS

Three public available datasets were used to train and validate the models. The experimental results demonstrated the effectiveness of the proposed network on laminar segmentation with an average Dice coefficient of 96.38% and an average symmetric surface distance of 0.097 mm.

CONCLUSION

The proposed two-stage network can achieve better results than those baseline models in the laminae segmentation task with less calculation amount and learnable parameters. Our methods improve the accuracy of laminar models and reduce the image processing time. It can be used to provide a more precise planning trajectory and may promote the clinical application for the robot-assisted decompression laminectomy surgery.

Robotics for Cochlear Implantation Surgery: Challenges and Opportunities

OBJECTIVES

Recent advancements in robotics have set forth a growing body of evidence for the clinical application of the robotic cochlear implantation (RCI), with many potential benefits. This review aims to summarize these efforts, provide the latest developments in this exciting field, and explore the challenges associated with the clinical implementation of RCI.

DATA SOURCES

MEDLINE, PubMed, and EMBASE databases.

STUDY SELECTION

A search was conducted using the keywords "robotics otolaryngology," "robotic cochlear implant," "minimally-invasive cochlear implantation," "minimally-invasive mastoidectomy," and "percutaneous cochlear implant" with all of their synonyms. Literature selection criteria included articles published in English, and articles from 1970 to present.

RESULTS

The use of robotics in neurotology is a relatively new endeavor that continues to evolve. Robotics is being explored by various groups to facilitate in the various steps of cochlear implant surgery, including drilling a keyhole approach to the middle ear for implants, inner ear access, and electrode insertion into the cochlea. Initial clinical trials have successfully implanted selected subjects using robotics.

CONCLUSIONS

The use of robotics in cochlear implants remains in its very early stages. It is hoped that robotics will improve clinical outcomes. Although successful implants with robots are reported in the literature, there are some challenges that need to be addressed before this approach can become an acceptable option for the conventional cochlear implant surgery, such as safety, time, efficiency, and cost. However, it is hoped that further advancements in robotic technology will help in overcoming these barriers leading to successful implementation for clinical utility.

Robot-Assisted Electrode Array Insertion Becomes Available in Pediatric Cochlear Implant Recipients: First Report and an Intra-Individual Study

Background: As an advanced surgical technique to reduce trauma to the inner ear, robot-assisted electrode array (EA) insertion has been applied in adult cochlear implantation (CI) and was approved as a safe surgical procedure that could result in better outcomes. As the mastoid and temporal bones are generally smaller in children, which would increase the difficulty for robot-assisted manipulation, the clinical application of these systems for CI in children has not been reported. Given that the pediatric candidate is the main population, we aim to investigate the safety and reliability of robot-assisted techniques in pediatric cochlear implantation.

Methods: Retrospective cohort study at a referral center in Shanghai including all patients of simultaneous bilateral CI with robotic assistance on one side (RobOtol® system, Collin ORL, Bagneux, France), and manual insertion on the other (same brand of EA and CI in both side), from December 2019 to June 2020. The surgical outcomes, radiological measurements (EA positioning, EA insertion depth, mastoidectomy size), and audiological outcomes (Behavior pure-tone audiometry) were evaluated.

Results: Five infants (17.8 ± 13.5 months, ranging from 10 to 42 months) and an adult (39 years old) were enrolled in this study. Both perimodiolar and lateral wall EAs were included. The robot-assisted EA insertion was successfully performed in all cases, although the surgical zone in infants was about half the size in adults, and no difference was observed in mastoidectomy size between robot-assisted and manual insertion sides (p = 0.219). The insertion depths of EA with two techniques were similar (P = 0.583). The robot-assisted technique showed no scalar deviation, but scalar deviation occurred for one manually inserted pre-curved EA (16%). Early auditory performance was similar to both techniques.

Conclusion: Robot-assisted technique for EA insertion is approved to be used safely and reliably in children, which is possible and potential for better scalar positioning and might improve long-term auditory outcome. Standard mastoidectomy size was enough for robot-assisted technique. This first study marks the arrival of the era of robotic CI for all ages.

Automated fiducial marker detection and localization in volumetric computed tomography images: a three-step hybrid approach with deep learning

Purpose: Automating fiducial detection and localization in the patient’s pre-operative images can lead to better registration accuracy, reduced human errors, and shorter intervention time. Most current approaches are optimized for a single marker type, mainly spherical adhesive markers. A fully automated algorithm is proposed and evaluated for screw and spherical titanium fiducials, typically used in high-accurate frameless surgical navigation.

Approach: The algorithm builds on previous approaches with morphological functions and pose estimation algorithms. A 3D convolutional neural network (CNN) is proposed for the fiducial classification task and evaluated for both traditional closed-set and emerging open-set classifiers. A proposed digital ground-truth experiment, with cone-beam computed tomography (CBCT) imaging software, is performed to determine the localization accuracy of the algorithm. The localized fiducial positions in the CBCT images by the presented algorithm were compared to the actual known positions in the virtual phantom models. The difference represents the fiducial localization error (FLE).

Results: A total of 241 screws, 151 spherical fiducials, and 1550 other structures are identified with the best true positive rate 95.9% for screw and 99.3% for spherical fiducials at 8.7% and 3.4% false positive rate, respectively. The best achieved FLE mean and its standard deviation for a screw and spherical marker are 58 (14) and 14 (6)  μm, respectively.

Conclusions: Accurate marker detection and localization were achieved, with spherical fiducials being superior to screws. Large marker volume and smaller voxel size yield significantly smaller FLEs. Attenuating noise by mesh smoothing has a minor effect on FLE. Future work will focus on expanding the CNN for image segmentation.

A New Pathogenic Variant in POU3F4 Causing Deafness Due to an Incomplete Partition of the Cochlea Paved the Way for Innovative Surgery

Incomplete partition type III (IP-III) is a relatively rare inner ear malformation that has been associated with a POU3F4 gene mutation. The IP-III anomaly is mainly characterized by incomplete separation of the modiolus of the cochlea from the internal auditory canal. We describe a 71-year-old woman with profound sensorineural hearing loss diagnosed with an IP-III of the cochlea that underwent cochlear implantation. Via targeted sequencing with a non-syndromic gene panel, we identified a heterozygous c.934G > C p. (Ala31Pro) pathogenic variant in the POU3F4 gene that has not been reported previously. IP-III of the cochlea is challenging for cochlear implant surgery for two main reasons: liquor cerebrospinalis gusher and electrode misplacement. Surgically, it may be better to opt for a shorter array because it is less likely for misplacement with the electrode in a false route. Secondly, the surgeon has to consider the insertion angles of cochlear access very strictly to avoid misplacement along the inner ear canal. Genetic results in well describes genotype-phenotype correlations are a strong clinical tool and as in this case guided surgical planning and robotic execution.

A Micro-Computed Tomography Study of Round Window Anatomy and Implications for Atraumatic Cochlear Implant Insertion

HYPOTHESIS

The goal of this study was to interrogate high-resolution three-dimensional reconstructions of round window anatomy to illustrate and characterize structural variability with implications for atraumatic cochlear implant insertion.

BACKGROUND

Cochlear implants are increasingly used to improve sound detection in patients with substantial residual hearing. However, traumatic cochlear implant insertion through the round window involving upward deviation of the electrode into the spiral ligament, basilar membrane, and osseous spiral lamina, medial impaction on the modiolus, or interscalar excursion into the scala vestibuli are associated with lower rates of hearing preservation and poorer speech perception.Successful atraumatic insertion is dependent on an anatomical understanding of the middle and inner ear. The round window bony niche lacks distinct demonstrable anatomical landmarks for the position of the round window membrane, and there is limited guidance on the amount of bony overhang that can be safely drilled away. A greater understanding of the anatomical variation around the round window could enhance treatment efficacy.

METHODS

Fourteen human cadaver temporal bones were imaged using microcomputed tomography. Resulting scans were digitally reconstructed, segmented, and measured.

RESULTS

Round window niche walls vary substantially in size and projection. Round window average short diameter measured 1.30 mm (range 1.07-1.44), and is limited by the crista fenestrae at the inferoanterior margin of the round window. Crista fenestrae size and morphology varied considerably. Reconstructions with solid and translucent panels are presented.

CONCLUSION

Anatomical heterogeneity should be considered in cochlear implant selection, drilling, and choice of insertion vector.

Preliminary clinical experience of robot-assisted surgery in treatment with genioplasty

Genioplasty is the main way to treat diseases such as chin asymmetry, dysplasia and overdevelopment, which involve the three-dimensional direction abnormalities of the chin. Since this kind of surgery mainly uses intraoral incisions, the narrow surgical field of intraoral incisions and the surrounding important neurovascular tissues make it easy for complications, to occur during the osteotomy process, which results in greater surgical risks. The first craniofacial-plastic surgical robot (CPSR-I) system is developed to complete the precise positioning and improve the surgeon's force perception ability. The Kalman filtering method is adopted to reduce the interference of sensor signal noise. An adaptive fuzzy control system, which has strong robustness and adaptability to the environment, is designed to improve the stability of robot-assisted surgical operations. To solve the problem of the depth perception, we propose an automatic bone drilling control strategy that combines position and force conditions to ensure that the robot can automatically stop when the bone is penetrated. On the basis of model surgery and animal experiments, preliminary experiments were carried out clinically. Based on the early results of 6 patients, the robot-assisted approach appears to be a safe and effective strategy for genioplasty.

Automatic segmentation of temporal bone structures from clinical conventional CT using a CNN approach

BACKGROUND

Automatic segmentation of temporal bone structures from patients' conventional computed tomography (CT) data plays an important role in the image-guided cochlear implant surgery. Existing convolutional neural network approaches have difficulties in segmenting such small tubular structures.

METHODS

We propose a light-weight three-dimensional convolutional neural network referred to as W-Net to achieve multiobjective segmentation of temporal bone structures including the cochlear labyrinth, ossicular chain and facial nerve from conventional temporal bone CT images. Data augmentation with morphological enhancement is proposed to increase the segmentation accuracy of small tubular structures. Evaluation against the state-of-the-art methods is performed.

RESULTS

Our method achieved mean Dice similarity coefficients (DSCs) of 0.90, 0.85 and 0.77 for the cochlear labyrinth, ossicular chain and facial nerve, respectively. These results were also close to the DSCs between human expert annotators (0.91, 0.91 and 0.72).

CONCLUSIONS

Our method achieves human-level accuracy in the segmentation of the cochlear labyrinth, ossicular chain and facial nerve.

Evolution and Stagnation of Image Guidance for Surgery in the Lateral Skull: A Systematic Review 1989-2020

Objective: Despite three decades of pre-clinical and clinical research into image guidance solutions as a more accurate and less invasive alternative for instrument and anatomy localization, translation into routine clinical practice for surgery in the lateral skull has not yet happened. The aim of this review is to identify challenges that need to be solved in order to provide image guidance solutions that are safe and beneficial for use during lateral skull surgery and to synthesize factors that facilitate the development of such solutions. Methods: Literature search was conducted via PubMed using terms relating to image guidance and the lateral skull. Data extraction included the following variables: image guidance error, imaging resolution, image guidance system, tracking technology, registration method, study endpoints, clinical target application, and publication year. A subsequent search of FDA 510(k) database for identified image guidance systems and extraction of the year of approval, intended use, and indications for use was performed. The study objectives and endpoints were subdivided in three time phases and summarized. Furthermore, it was analyzed which factors correlated with the image guidance error. Factor values for which an error ≤0.5 mm (μ_error + 3σ_error) was measured in more than one study were identified and inspected for time trends. Results: A descriptive statistics-based summary of study objectives and findings separated in three time intervals is provided. The literature provides qualitative and quantitative evidence that image guidance systems must provide an accuracy ≤0.5 mm (μ_error + 3σ_error) for their safe and beneficial application during surgery in the lateral skull. Spatial tracking accuracy and precision and medical image resolution both correlate with the image guidance accuracy, and all of them improved over the years. Tracking technology with accuracy ≤0.05 mm, computed tomography imaging with slice thickness ≤0.2 mm, and registration based on bone-anchored titanium fiducials are components that provide a sufficient setting for the development of sufficiently accurate image guidance. Conclusion: Image guidance systems must reliably provide an accuracy ≤0.5 mm (μ_error + 3σ_error) for their safe and beneficial use during surgery in the lateral skull. Advances in tracking and imaging technology contribute to the improvement of accuracy, eventually enabling the development and wide-scale adoption of image guidance solutions that can be used safely and beneficially during lateral skull surgery.

The use of a surgical planning tool for evaluating the optimal surgical accessibility to the stapedius muscle via a retrofacial approach during cochlear implant surgery: a feasibility study

PURPOSE

During cochlear implant (CI) surgery, visual detection of the stapedius reflex as movements of the stapes tendon, electrically elicited via the CI, is a standard measure to confirm the system's functionality. Direction visualization of the stapedius muscle (SM) movements might be more reliable, but a safe access to the small SM is not defined. A new surgical planning tool for pre-operative evaluation of the accessibility to the stapedius muscle (SM) during a cochlear implantation (CI) via a retrofacial approach was now evaluated.

METHODS

A surgical planning tool was developed in MATLAB using an image processing algorithm to evaluate drilling feasibility. A flat-panel computed tomography (CT) combining a rotational angiographic C-arm units with flat-panel detectors (Dyna-CT) was used. In total, 30 3D Dyna-CT-based temporal bone reconstructions were evaluated by automatized algorithms, generating a series of trajectories and comparing their feasibility and safety to reach the SM via a retrofacial approach. The predictability of the surgical planning tool results was tested in 5 patients.

RESULTS

The surgical planning tool showed that a retrofacial access to the SM would be feasible in 25/30 cases. Moreover, the evaluation of the predictability of the results obtained with the surgical planning tool conducted during 5 CI surgeries confirmed the results. Both the surgical planning tool and the results on SM accessibility via retrofacial approach during CI showed that this is safe and feasible only when the SM-exposed area was > 25% of its total, the distance between the SM and the facial nerve was > 0.8 mm, and the surgical corridor diameter was > 3 mm.

CONCLUSION

The surgical planning tool seems to be useful for the pre-operative evaluation of the accessibility to the SM during a CI surgery via a retrofacial approach. Further prospective studies are needed to validate the results in larger cohorts.

Computational Optimization of Notch Spacing for a Transnasal Ear Endoscopy Continuum Robot

This paper presents a computational framework to optimize the visual coverage attainable by a notched-tube continuum robotic endoscope inside the middle ear cavity. Our framework combines anatomically-accurate geometric (mesh) models of the middle ear with a sampling-based motion planning algorithm (RRT) and a ray-casting procedure to quantify what regions of the middle ear can be accessed and visualized by the endoscope. To demonstrate the use of this framework, we run computer simulations to investigate the effect of varying the distance between each pair of consecutive flexure elements (i.e., notches) in our robotic endoscope.

Image-guided cochlear access by non-invasive registration: a cadaveric feasibility study

Image-guided cochlear implant surgery is expected to reduce volume of mastoidectomy, accelerate recovery, and improve safety. The purpose of this study was to investigate the safety and effectiveness of image-guided cochlear implant surgery by a non-invasive registration method, in a cadaveric study. We developed a visual positioning frame that can utilize the maxillary dentition as a registration tool and completed the tunnels experiment on 5 cadaver specimens (8 cases in total). The accuracy of the entry point and the target point were 0.471 ± 0.276 mm and 0.671 ± 0.268 mm, respectively. The shortest distance from the margin of the tunnel to the facial nerve and the ossicular chain were 0.790 ± 0.709 mm and 1.960 ± 0.630 mm, respectively. All facial nerves, tympanic membranes, and ossicular chains were completely preserved. Using this approach, high accuracy was achieved in this preliminary study, suggesting that the non-invasive registration method can meet the accuracy requirements for cochlear implant surgery. Based on the above accuracy, we speculate that our method can also be applied to neurosurgery, orbitofacial surgery, lateral skull base surgery, and anterior skull base surgery with satisfactory accuracy.

Acceptance of patients towards task-autonomous robotic cochlear implantation: An exploratory study

Background

Recently, task‐autonomous image‐guided robotic cochlear implantation has been successfully completed in patients. However, no data exist on patients' perspective of this new technology. The aim of this study was to evaluate the acceptance of patients towards task‐autonomous robotic cochlear implantation (TARCI).

Methods

We prospectively surveyed 63 subjects (51 patients and 12 parents of infants) scheduled for manual cochlear implantation. We collected sociodemographic and clinico‐pathological characteristics and their attitude towards TARCI for themselves or their child using a questionnaire. Differences between variables were analysed using one‐way analysis of variance and Spearman's rho was used to test for correlation.

Results

Seventy‐three percent of patients and 84% of parents expressed a high acceptance towards TARCI for themselves, or their child, respectively. Interestingly, patients with a negative attitude towards TARCI were significantly younger.

Conclusion

The attitude of patients and parents likely does not represent a barrier towards application of this new technology.

A simple tool to automate the insertion process in cochlear implant surgery

Purpose

Automated insertion of electrode arrays (EA) in cochlear implant surgery is presumed to be less traumatic than manual insertions, but no tool is widely available in the operating room. We sought (1) to design and create a simple tool able to automate the EA insertion process; and (2) to perform preliminary evaluations of the designed prototype.

Methods

A first prototype of a tool with maximum simplicity was designed and fabricated to take advantage of hydraulic actuation. The prototype facilitates automated forward motion using a syringe connected to an infusion pump. Initial prototype evaluation included: (1) testing of forward motion at different velocities (2) EA insertion trials into an artificial cochlear model with force recordings, and (3) evaluation of device handling, fixation and positioning using cadaver head specimens and a surgical retractor. Alignment of the tool was explored with CT imaging.

Results

In this initial phase, the prototype demonstrated easy assembly and ability to respond to hydraulic actuation driven by an infusion pump at different velocities. EA insertions at an ultra-slow velocity of 0.03 mm/s revealed smooth force profiles with mean maximum force of 0.060 N ± 0.007 N. Device positioning with an appropriate insertion axis into the cochlea was deemed feasible and easy to achieve.

Conclusions

Initial testing of our hydraulic insertion tool did not reveal any serious complications that contradict the initially defined design specifications. Further meticulous testing is needed to determine the safety of the device, its reliability and clinical applicability.

Optical Coherence Tomography-Guided Robotic Ophthalmic Microsurgery via Reinforcement Learning from Demonstration

Ophthalmic microsurgery is technically difficult because the scale of required surgical tool manipulations challenge the limits of the surgeon's visual acuity, sensory perception, and physical dexterity. Intraoperative optical coherence tomography (OCT) imaging with micrometer-scale resolution is increasingly being used to monitor and provide enhanced real-time visualization of ophthalmic surgical maneuvers, but surgeons still face physical limitations when manipulating instruments inside the eye. Autonomously controlled robots are one avenue for overcoming these physical limitations. We demonstrate the feasibility of using learning from demonstration and reinforcement learning with an industrial robot to perform OCT-guided corneal needle insertions in an ex vivo model of deep anterior lamellar keratoplasty (DALK) surgery. Our reinforcement learning agent trained on ex vivo human corneas, then outperformed surgical fellows in reaching a target needle insertion depth in mock corneal surgery trials. This work shows the combination of learning from demonstration and reinforcement learning is a viable option for performing OCT guided robotic ophthalmic surgery.

Comparison of the Surgical Techniques and Robotic Techniques for Cochlear Implantation in Terms of the Trajectories Toward the Inner Ear

OBJECTIVES

The ideal outcome of cochlear implant surgery involves the insertion of the array inside the scala tympani of the cochlea with the least mechanical trauma. Recently, round window insertion and the direction in which the cochlea is approached have gained attention in this respect. The Angles of Cochlear Approach (ACA) can be defined with a plane in the plane of the basal turn, termed the in-plane angle, and the plane orthogonal to this plane, termed the out-plane angle. The aim of this study was to compare the trajectory angles for different surgical techniques of Veria, suprameatal, pericanal, and multiple posterior tympanotomy (PT) approaches, including an optimal trajectory that is simulated for robotic surgery.

MATERIALS AND METHODS

The trajectories of these surgical techniques were simulated on the same high-resolution computed tomography scan. The simulated trajectory angles were analyzed with dedicated software for medical images, defining the ACA and distances to critical otological structures.

RESULTS

The ACA are the smallest for surgical techniques that pass thought the PT. However, performing a surgical PT can include variability in the ACA, ranging from almost 0° to 20.8° in an out-plane angle, depending on how close a surgeon would approach the facial nerve. The Veria, Suprameatal approach (SMA), and peri-canal approaches have larger ACA and minimal distances to the ossicular chain and the ear canal. The maximum distance to the facial nerve and the widest out-plane angle is observe with a pericanal approach. The optimal PT approach refers to the trajectory without collisions and with the best possible ACA that can be planned.

CONCLUSION

Different surgical approaches yield important differences in the ACA. PT allows better ACA with maximum distances to the critical structures. However, the optimal PT trajectory simulated for robotic keyhole surgery is a further improvement on the trajectories through the facial recess.

Improvements to the retractor and muscle flap design for minimally invasive cochlear implantation

Objective

The aim of this study was to improve muscle flaps and to evaluate surgical outcomes with the use of a novel specialized retractor, which is a surgical instrument used to locate and shape a bony seat for minimally invasive cochlear implantation.

Methods

50 patients aged 1-75 years with sensorineural hearing loss who required cochlear implantation were recruited. A small incision (<3 cm) was made, and the novel specialized retractor was used in the study group during cochlear implantation. The incision length, surgical outcomes and operative time were recorded and analyzed.

Results

The incision length, total operative time and drilling bony time were shorter in the study group than in the control group (P < 0.05, respectively). All patients recovered well after the surgery without any severe complications.

Conclusion

The use of a novel specialized retractor standardized the surgical processes of cochlear implantation. The retractor helped locate and control the size of the bony well during bone drilling. The tool reduced the technical difficulty and improved the efficacy of this minimally invasive operation.

Robots and Tools for Remodeling Bone

The field of robotic surgery has progressed from small teams of researchers repurposing industrial robots, to a competitive and highly innovative subsection of the medical device industry. Surgical robots allow surgeons to perform tasks with greater ease, accuracy, or safety, and fall under one of four levels of autonomy; active, semi-active, passive, and remote manipulator. The increased accuracy afforded by surgical robots has allowed for cementless hip arthroplasty, improved postoperative alignment following knee arthroplasty, and reduced duration of intraoperative fluoroscopy among other benefits. Cutting of bone has historically used tools such as hand saws and drills, with other elaborate cutting tools now used routinely to remodel bone. Improvements in cutting accuracy and additional options for safety and monitoring during surgery give robotic surgeries some advantages over conventional techniques. This article aims to provide an overview of current robots and tools with a common target tissue of bone, proposes a new process for defining the level of autonomy for a surgical robot, and examines future directions in robotic surgery.

Prospective Validation of Facial Nerve Monitoring to Prevent Nerve Damage During Robotic Drilling

Facial nerve damage has a detrimental effect on a patient's life, therefore safety mechanisms to ensure its preservation are essential during lateral skull base surgery. During robotic cochlear implantation a trajectory passing the facial nerve at <0.5 mm is needed. Recently a stimulation probe and nerve monitoring approach were developed and introduced clinically, however for patient safety no trajectory was drilled closer than 0.4 mm. Here we assess the performance of the nerve monitoring system at closer distances. In a sheep model eight trajectories were drilled to test the setup followed by 12 trajectories during which the ENT surgeon relied solely on the nerve monitoring system and aborted the robotic drilling process if intraoperative nerve monitoring alerted of a distance <0.1 mm. Microcomputed tomography images and histopathology showed prospective use of the technology prevented facial nerve damage. Facial nerve monitoring integrated in a robotic system supports the surgeon's ability to proactively avoid damage to the facial nerve during robotic drilling in the mastoid.

Robotic middle ear access for cochlear implantation: First in man

To demonstrate the feasibility of robotic middle ear access in a clinical setting, nine adult patients with severe-to-profound hearing loss indicated for cochlear implantation were included in this clinical trial. A keyhole access tunnel to the tympanic cavity and targeting the round window was planned based on preoperatively acquired computed tomography image data and robotically drilled to the level of the facial recess. Intraoperative imaging was performed to confirm sufficient distance of the drilling trajectory to relevant anatomy. Robotic drilling continued toward the round window. The cochlear access was manually created by the surgeon. Electrode arrays were inserted through the keyhole tunnel under microscopic supervision via a tympanomeatal flap. All patients were successfully implanted with a cochlear implant. In 9 of 9 patients the robotic drilling was planned and performed to the level of the facial recess. In 3 patients, the procedure was reverted to a conventional approach for safety reasons. No change in facial nerve function compared to baseline measurements was observed. Robotic keyhole access for cochlear implantation is feasible. Further improvements to workflow complexity, duration of surgery, and usability including safety assessments are required to enable wider adoption of the procedure.

A "eye-in-body" integrated surgery robot system for stereotactic surgery

PURPOSE

Current stereotactic surgical robots system relies on cumbersome operations such as calibration, tracking and registration to establish the accurate intraoperative coordinate transformation chain, which makes the system not easy to use. To overcome this problem, a novel stereotactic surgical robot system has been proposed and validated.

METHODS

First, a hand-eye integrated scheme is proposed to avoid the intraoperative calibration between robot arm and motion tracking system. Second, a special reference-tool-based patient registration and tracking method is developed to avoid intraoperative registration. Third, a model-free visual servo method is used to reduce the accuracy requirement of hand-eye relationship and robot kinematic model. Finally, a prototype of the system is constructed and performance tests and a pedicle screw drilling experiment are performed.

RESULTS

The results show that the proposed system has acceptable accuracy. The target positioning error in the plane was - 0.68 ± 0.52 mm and 0.06 ± 0.41 mm. The orientation error was 0.43 ± 0.25°. The pedicle screw drilling experiment shows that the system can complete accurate stereotactic surgery.

CONCLUSIONS

The stereotactic surgical robot system described in this paper can perform stereotactic surgery without the intraoperative hand-eye calibration and nor manual registration and can achieve an acceptable position and orientation accuracy while tolerating the errors in the hand-eye coordinate transformation error and the robot kinematics model error.

Frontiers of Medical Robotics: From Concept to Systems to Clinical Translation

Medical robotics is poised to transform all aspects of medicine—from surgical intervention to targeted therapy, rehabilitation, and hospital automation. A key area is the development of robots for minimally invasive interventions. This review provides a detailed analysis of the evolution of interventional robots and discusses how the integration of imaging, sensing, and robotics can influence the patient care pathway toward precision intervention and patient-specific treatment. It outlines how closer coupling of perception, decision, and action can lead to enhanced dexterity, greater precision, and reduced invasiveness. It provides a critical analysis of some of the key interventional robot platforms developed over the years and their relative merit and intrinsic limitations. The review also presents a future outlook for robotic interventions and emerging trends in making them easier to use, lightweight, ergonomic, and intelligent, and thus smarter, safer, and more accessible for clinical use.