In Vitro Accuracy Evaluation of Image-Guided Robot System for Direct Cochlear Access

Bell, Brett; Gerber, Nicolas U.; Williamson, Tom; Gavaghan, Kate; Wimmer, Wilhelm; Caversaccio, Marco; Weber, Stefan

doi:10.1097/mao.0b013e31829561b6

Cited by 79 publications

(88 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…After immobilization of the animal's head using a pin type head-clamp, a high-accuracy image-guided surgical robot system (12,22,29,30) was used to drill to each of the predefined measurement points in the planned trajectories (see Video, Supplemental Digital Content 1, http://links.lww.com/MAO/ A345, which shows how the image-guided robotic system drills to the next measurement point). Upon reaching a given measurement position, the drill was removed, and to ensure good electrical contact between electrodes and bony tissue, irrigation (NaCl, 0.9%) was applied.…”

Section: Drilling and Facial Nerve Stimulation Measurementsmentioning

confidence: 99%

“…Recently, two studies (11,12) have demonstrated sufficient end-to-end image-guided drilling accuracies of 0.31 AE 0.1 and 0.15 AE 0.08 mm using templates and a robotic guidance respectively, suggesting their potential clinical implementation. The minimally invasive approach is based on the creation of a small diameter tunnel (1.5-2 mm) from the surface of the patient's mastoid to the cochlea following a preoperatively planned path through the facial recess.…”

mentioning

confidence: 99%

“…The minimally invasive approach is based on the creation of a small diameter tunnel (1.5-2 mm) from the surface of the patient's mastoid to the cochlea following a preoperatively planned path through the facial recess. The approach results in the drilling tool passing within close proximity (0.1-1.2 mm [6,12]) of the facial nerve (FN), placing this vital structure at risk from either excessive drilling temperature or mechanical destruction by collision with the drill bit. Although electromyogram (EMG)-based neuromonitoring has become a standard safety mechanism for identification and preservation of the FN in middle ear surgeries, such as revision cases and cochlear implantations (13)(14)(15)(16)(17)(18)(19)(20)(21), it has yet to achieve the sensitivity and specificity required to become a reliable safety mechanism when operating in close vicinity of the FN (<0.3 mm), without line of sight to the surrounding anatomy.…”

mentioning

confidence: 99%

See 2 more Smart Citations

A Neuromonitoring Approach to Facial Nerve Preservation During Image-guided Robotic Cochlear Implantation

Ansó

Dür

Gavaghan

et al. 2016

Otology &Amp; Neurotology

Self Cite

View full text Add to dashboard Cite

Hypothesis: A multielectrode probe in combination with an optimized stimulation protocol could provide sufficient sensitivity and specificity to act as an effective safety mechanism for preservation of the facial nerve in case of an unsafe drill distance during image-guided cochlear implantation. Background: A minimally invasive cochlear implantation is enabled by image-guided and robotic-assisted drilling of an access tunnel to the middle ear cavity. The approach requires the drill to pass at distances below 1 mm from the facial nerve and thus safety mechanisms for protecting this critical structure are required. Neuromonitoring is currently used to determine facial nerve proximity in mastoidectomy but lacks sensitivity and specificity necessaries to effectively distinguish the close distance ranges experienced in the minimally invasive approach, possibly because of current shunting of uninsulated stimulating drilling tools in the drill tunnel and because of nonoptimized stimulation parameters. To this end, we propose an advanced neuromonitoring approach using varying levels of stimulation parameters together with an integrated bipolar and monopolar stimulating probe. Materials and Methods: An in vivo study (sheep model) was conducted in which measurements at specifically planned and navigated lateral distances from the facial nerve were performed to determine if specific sets of stimulation parameters in combination with the proposed neuromonitoring system could reliably detect an imminent collision with the facial nerve. For the accurate positioning of the neuromonitoring probe, a dedicated robotic system for image-guided cochlear implantation was used and drilling accuracy was corrected on postoperative microcomputed tomographic images. Results: From 29 trajectories analyzed in five different subjects, a correlation between stimulus threshold and drillto-facial nerve distance was found in trajectories colliding with the facial nerve (distance <0.1 mm). The shortest pulse duration that provided the highest linear correlation between stimulation intensity and drill-to-facial nerve distance was 250 ms. Only at low stimulus intensity values ( 0.3 mA) and with the bipolar configurations of the probe did the neuromonitoring system enable sufficient lateral specificity (>95%) at distances to the facial nerve below 0.5 mm. However, reduction in stimulus threshold to 0.3 mA or lower resulted in a decrease of facial nerve distance detection range below 0.1 mm (>95% sensitivity). Subsequent histopathology follow-up of three representative cases where the neuromonitoring system could reliably detect a collision with the facial nerve (distance <0.1 mm) revealed either mild or inexistent damage to the nerve fascicles. Conclusion: Our findings suggest that although no general correlation between facial nerve distance and stimulation threshold existed, possibly because of variances in patient-specific anatomy, correlations at very close distances to the facial nerve and high levels of specificity would enable a binary respo...

show abstract

Section: Drilling and Facial Nerve Stimulation Measurementsmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

A Neuromonitoring Approach to Facial Nerve Preservation During Image-guided Robotic Cochlear Implantation

Ansó

Dür

Gavaghan

et al. 2016

Otology &Amp; Neurotology

Self Cite

View full text Add to dashboard Cite

show abstract

“…The procedure, which involves the drilling of a direct tunnel from the mastoid surface to the middle ear cavity relies on image guidance to ensure structure preservation. Up to date, there is no established minimally invasive procedure, but an image guided surgical robot [7], developed at the university of Bern, has demonstrated sufficient accuracy in ex vivo experiments (less than 0.15 ± 0.08mm [6]) to allow precise drilling of the tunnel without damaging close lying anatomy.…”

Section: Introductionmentioning

confidence: 99%

Temperature Prediction Model for Bone Drilling Based on Density Distribution and In Vivo Experiments for Minimally Invasive Robotic Cochlear Implantation

et al. 2015

Self Cite

View full text Add to dashboard Cite

Surgical robots have been proposed ex vivo to drill precise holes in the temporal bone for minimally invasive cochlear implantation. The main risk of the procedure is damage of the facial nerve due to mechanical interaction or due to temperature elevation during the drilling process.To evaluate the thermal risk of the drilling process, a simplified model is proposed which aims to enable an assessment of risk posed to the facial nerve for a given set of constant process parameters for different mastoid bone densities. The model uses the bone density distribution along the drilling trajectory in the mastoid bone to calculate a time dependent heat production function at the tip of the drill bit. Using a time dependent moving point source Green's function, the heat equation can be solved at a certain point in space so that the resulting temperatures can be calculated over time. The model was calibrated and initially verified with in vivo temperature data. The data was collected in minimally invasive robotic drilling of 12 holes in four different sheep. The sheep were anesthetized and the temperature elevations were measured with a thermocouple which was inserted in a previously drilled hole next to the planned drilling trajectory. Bone density distributions were extracted from pre-operative CT data by averaging Hounsfield values over the drill bit diameter. Post-operative µCT data was used to verify the drilling accuracy of the trajectories. The comparison of measured and calculated temperatures shows a very good match for both heating and cooling phases. The average prediction error of the maximum temperature was less than 0.7°C and the average root mean square error was approximately 0.5°C. To analyze potential thermal damage, the model was used to calculate temperature profiles and cumulative equivalent minutes at 43°C at a minimal distance to the facial nerve. For the selected drilling parameters, temperature elevation profiles and cumulative equivalent minutes suggest that thermal elevation of this minimally invasive cochlear implantation surgery may pose a risk to the facial nerve, especially in sclerotic or high density mastoid bones. Optimized drilling parameters need to be evaluated and the model could be used for future risk evaluation.

show abstract

“…[2][3][4][5][6] Another proposed method utilized a self-developed and constructed robot to drill along a specified path, by which high resolution surgery could be achieved. [7,8] Registration is an important aspect of surgical navigation resolution. However, due to the registration of the navigation system, the infliction of additional trauma cannot be ignored in the above two approaches.…”

Section: Introductionmentioning

confidence: 99%

Application of bonebed-malleus short process registration in minimally invasive cochlear implantation

Zhang

et al. 2016

Computer Assisted Surgery

View full text Add to dashboard Cite

Purpose: This article proposed and investigated the application of bonebed-malleus short process registration in minimally invasive cochlear implantation, and assessed the value of the proposed strategy for image-guided otologic surgery. Materials and methods: Ten temporal bone specimens were marked with both shallow and deep targets in order to measure registration resolutions. Two registration methods were applied. Method A (a new registration method) consisted of bonebed-malleus short process registration, while method B (traditional registration method) comprised registration using four titanium screws attached at the mastoid surface. The target registration errors (TRE) were measured at both the shallow and deep fiducial targets. After registration achieved by method A, percutaneous cochlear drilling was conducted on the other eight temporal bone specimens in order to observe the deviation from the target point and entry point. Results: Using method A, the error observed at the shallow fiducial markers of specimens was less than 1 mm, while the error observed at the deep fiducial markers was approximately equal to 1 mm. No significant difference was observed when results were compared with the application of method B. In eight studied cases using method A, drilling operations were successfully conducted. The deviations from the target point and the entry point were 0.84 ± 0.30 and 0.66 ± 0.51 mm, respectively. Conclusions: Results of the present study indicated that the new registration method demonstrated identical accuracy when compared to traditional registration method, achieved less invasiveness. Thus, the proposed method might be a feasible registration method for image-guided otologic surgery due to its mild invasiveness and high accuracy.

show abstract

In Vitro Accuracy Evaluation of Image-Guided Robot System for Direct Cochlear Access

Abstract: The purpose-built robot system was able to perform a safe and reliable DCA for cochlear implantation. The workflow implemented in this study mimics the envisioned clinical procedure showing the feasibility of future clinical implementation.

Cited by 79 publications

References 16 publications

A Neuromonitoring Approach to Facial Nerve Preservation During Image-guided Robotic Cochlear Implantation

A Neuromonitoring Approach to Facial Nerve Preservation During Image-guided Robotic Cochlear Implantation

Temperature Prediction Model for Bone Drilling Based on Density Distribution and In Vivo Experiments for Minimally Invasive Robotic Cochlear Implantation

Application of bonebed-malleus short process registration in minimally invasive cochlear implantation

Contact Info

Product

Resources

About