ナビゲーションガイドにより除去できた顔面深部異物の1例

To compare patients' radiation exposure, technical feasibility, imaging quality and complication rate of percutaneous lung biopsies (PLBs) performed with a low-dose (LD) CT protocol under guidance of an optical navigation system. Fifty-two consecutive patients with suspected malignant lung lesions were enrolled and randomised into group 1 (PLBs under the guidance of the navigation system) and group 2 (PLBs under the guidance navigation system with an LD protocol). Patients' demographics, lesion features, procedure-related variables and CT image quality for group 2 were recorded and compared. Technical success was 100 % in both groups. The radiation dose to patients' chest was significantly lower in group 2 than in group 1 (group 1: mean TDLP 206 ± 59 mGy·cm, ~ 3.5 ± 1.0 mSv; group 2: 54.2 ± 46.2 mGy·cm, ~ 0.92 ± 0.78 mSv; P < 0.0001). The PNX rate was 12 % in group 1 and 11.1 % in group 2. The haemoptysis rate was 8.0 % in group 1 and 3.7 % in group 2. CT image quality obtained in group 2 was always rated as adequate and as excellent in 15 cases (56.0 %). An optical navigation system with LD CT protocol is useful for performing lung biopsies with decreased patient radiation exposure. • Navigation systems are useful tools in percutaneous imaging-guided procedures. • For lung biopsies, low-dose (LD) CT protocols may be used. • Combining LD protocols with optical CT navigation results in significantly reduced radiation exposure.

Improving machine vision in robotic systems for large-scale sensing in forestry is more relevant than ever. Currently, most UAVs are equipped with various navigation systems (SN), including optical ones. Automatic return-to-point systems are also widely used. These systems are used to facilitate piloting by aircraft, or activated in case of emergency situations. There are also optical tracking systems for the object, which are used mainly in video shooting. Optical navigation systems can be used to more accurately position spaces, and can also be used as a backup navigation system when the main navigation system fails.

Radiofrequency ablation (RFA) is a crucial alternative treatment for liver cancer with the advantages of minimal invasion and a fast prognosis. However, two problems limit its further application: the orientation of the puncture point and the ablation of large tumors. The optical surgery navigation system in the RFA presents a promising approach for solving the localization problem in the puncturing process, which greatly increases puncture accuracy and has overcome the disadvantages of traditional RFA surgery. In addition, the use of multiple electrodes in the RFA (multi-probe RFA) is proposed and is applied clinically to deal with large tumors. In this study, we present a multi-probe RFA model using the finite element method (FEM) combined with a self-developed optical surgical navigation system. A real 3D liver model was adopted as an effective reference. Based on this model, two-probe RFA simulations were performed under different active modes. An analysis was conducted from the perspective of the temperature and electric potential fields and cell necrosis. The simulation results showed that different active modes had separate advantages and were suitable for different situations. Understanding their advantages can not only help doctors make surgical plans that fit the patients’ conditions, but also the understanding can offer a virtual surgery platform for further development in the preoperative planning of RFA incorporated with the surgery navigation system.

Purpose: Many studies have been conducted on assessment of navigation accuracy on cadaver head using pre-installed CT fiducials. However, there are fewer studies on assessing accuracy on real patient due to its complexity in measuring Target Registration Error (TRE). In this paper we propose a new approach for quantifying navigation accuracy on the real patients. This paper summarizes the results of navigation accuracy of a novel optical image guided navigation system evaluated on over 20 patients. Method: Commercially available optical navigation system (Navient Image guided navigation system - ClaroNav Kolahi Inc., Toronto, Canada) was used on over 20 patients from 2017 to 2019. Navient employs both landmarks based and trace based registration. Since mounting CT fiducials on the real patients is invasive and impractical, we developed a new approach to measure the distance from the navigation probe to the patient’s skin as a new metric to quantify navigation accuracy. The measurement was conducted in dozens of locations including patient’s forehead, temples and base of the nose. These anatomical locations were chosen very carefully to represent navigation accuracy in coronal, sagittal and axial directions respectively. Furthermore, our method also eliminates human errors involved in the TRE measurements which is the main source of error in TRE studies. Results: The average Euclidian distance from skin on 23 patients were 1.47(mm). the standard deviation of the accuracy was 0.28(mm). Low STD demonstrates consistent accuracy during the two year course of the study. Conclusion: A new noninvasive approach for accuracy assessment of image guided navigation systems on real patient was proposed and validated using a novel optical navigation system. The low STD of navigation accuracy indicates its reliable accuracy.

Navigation in total hip arthroplasty has been shown to improve acetabular positioning and can decrease the incidence of mal-positioned acetabular components. The aim of this study was to assess two surgical guidance systems by comparing intra-operative measurements of acetabular component inclination and anteversion with a post-operative CT scan.We prospectively collected intra-operative navigation data from 102 hips receiving conventional THA or hip resurfacing arthroplasty through either a direct anterior or posterior approach. Two guidance systems were used simultaneously: an inertial navigation system (INS) and optical navigation system (ONS). Acetabular component anteversion and inclination was measured on a post-operative CT.The average age of the patients was 64 years (range: 24-92) and average BMI was 27 kg/m2 (range 19-38). 52% had hip surgery through an anterior approach. 98% of the INS measurements and 88% of the ONS measurements were within 10° of the CT measurements. The mean (and standard deviation) of the absolute difference between the post-operative CT and the intra-operative measurements for inclination and anteversion were 3.0° (2.8) and 4.5° (3.2) respectively for the ONS, along with 2.1° (2.3) and 2.4° (2.1) respectively for the INS. There was significantly lower mean absolute difference to CT for the INS when compared to ONS in both anteversion (p&lt;0.001) and inclination (p=0.02).Both types of navigation produced reliable and reproducible acetabular cup positioning. It is important that patient-specific planning and navigation are used together to ensure that surgeons are targeting the optimal acetabular cup position. This assistance with cup positioning can provide benefits over free-hand techniques, especially in patients with an altered acetabular structure or extensive acetabular bone loss.In conclusion, both ONS and INS allowed for adequate acetabular positioning as measured on postoperative CT, and thus provide reliable intraoperative feedback for optimal acetabular component placement.

Poster 046: Maxillary Cancer Treatment Under the CT-Navigation System

This study presents the first report in the same patients on the time efficiency of surface registration as well as the navigational accuracy using optic and electromagnetic tracking systems. Thirty patients with bilateral chronic paranasal pansinusitis underwent endoscopic sinus surgery. After surface registration, the surgeries were performed on one side using optic navigation guidance and on the other side using electromagnetic navigation guidance. The intraoperative measurements performed included the time taken for the surface registration and surgical procedure on each side, as well as the navigation errors at the different locations. The time for surface registration was significantly longer in the optic navigation group than the electromagnetic group. A comparison of the navigation errors along the 3 axes showed that the deviation in the medial-lateral direction was significantly less than that in the anterior-posterior and cranial-caudal directions in the optic navigation group as well as the electromagnetic group. The procedure for surface registration in both optic and electromagnetic guidance is efficient and convenient. The accuracy of both navigation systems is comparable and within acceptable ranges for clinical use. In addition, the best accuracy was measured in the medial-lateral direction compared with the other two axes.

Navigation in total hip arthroplasty has been shown to improve acetabular positioning and can decrease the incidence of mal-positioned acetabular components. This study aimed to assess two surgical guidance systems by comparing intra-operative measurements of acetabular component inclination and anteversion with a post-operative CT scan. We prospectively collected intra-operative navigation data from 102 hips receiving conventional THA or hip resurfacing arthroplasty through either a direct anterior or posterior approach. Two guidance systems were used simultaneously: an inertial navigation system (INS) and an optical navigation system (ONS). Acetabular component anteversion and inclination were measured on a post-operative CT. The average age of the patients was 64years (range: 24-92) and the average BMI was 27kg/m2 (range 19-38). 52% had hip surgery through an anterior approach. 98% of the INS measurements and 88% of the ONS measurements were within 10° of the CT measurements. The mean (and standard deviation) of the absolute difference between the postoperative CT and the intra-operative measurements for inclination and anteversion were 3.0° (2.8) and 4.5° (3.2) respectively for the ONS, along with 2.1° (2.3) and 2.4° (2.1) respectively for the INS. There was a significantly lower mean absolute difference to CT for the INS when compared to ONS in both anteversions (p<0.001) and inclination (p=0.02). We found that both inertial and optical navigation systems allowed for adequate acetabular positioning as measured on postoperative CT, and thus provide reliable intraoperative feedback for optimal acetabular component placement. Therapeutic Level II.

This paper presents a phantom study that was conducted for an ultrasound-guided shoulder arthroscopy navigation system. The navigation system uses a surface model generated from pre-operative computed tomography images, which has to be registered to the patient during the procedure. The goal of this study was to determine the optimal regions on the scapula bone of the shoulder to achieve an acceptable registration. Experiments were performed to examine the robustness and suitability of these optimal regions by testing the sensitivity to variations in the initial alignment for two different registration algorithms, namely iterative closest point and sequential least squares estimation technique. The fiducial registration error was analyzed and compared for all experiments. Regions spread over the entire scapula result in significantly smaller registration error (p<0.001) than regions, concentrated around the shoulder joint and thus accessible during the shoulder arthroscopy. However, the results also showed that the registration is still acceptable for the image- guided navigation system when these accessible landmarks are used

Delivering a spacecraft to the outer planets with high precision (la « 200 km) and supporting the desired high accuracy instrument pointing near a planetary encounter place great demands on a navigation system. A combined Earth-based radio tracking/onboard optical data navigation system designed to meet these goals, is described in this paper. Some results of applying this navigation system to the preliminary Mariner-Jupiter-Saturn 1977 mission trajectories (the Jupiter approach of the JSX-flight and the Saturn approach of the JST-flight) are presented. It is shown that this system is capable of providing target planet centered orbit determination accuracies in the range of 100 Jem, and accuracies relative to closely encountered satellites of about 200-250 km, provided there is accurate modeling of the natural satellite motions. Analytical theories of the satellite motions would be attractive from the cost and time usage standpoint as alternatives to numerical integration of the equations of motion. An analytical theory (ignoring the mutual perturbations) is investigated for this role. It is concluded that further development of these theories will have to be undertaken before they can be used for high precision navigation.

Preoperative planning and intraoperative navigation in skull base surgery

From November 2015 to January 2016, two patients with multiple maxillofacial fractures were chosen to undergo CT scanning and maxillofacial three-dimensional (3D) imaging reconstruction. The data were input to 3D printer in order to yield rapid prototyping model with the same size of patients′ maxillofacial regions. Simulated fracture surgery and reconstruction of the Ti-palate were performed on the models. The operations were conducted with the guidance of navigation system. The consistency of simulated model and real fractures was compared. The results show the complex maxillofacial fracture could make the operation more accurate and shorten the operation time. Moreover, the facial features and masticatory function of both patients were improved. The 3D printing technique combined with computer-assisted navigation could be applied to complex maxillofacial fractures surgery, in order to improve the surgical accuracy and achieve effective reconstruction. Key words: Three dimensional printing; Computer aided, navigation system; Fracture; Craniomaxillofaial surgery; Skull, model

ASPIRATION OF NASAL RING IN YOUNG HEALTHY FEMALE ADULT

Mandibular reconstruction is an extremely complex and high-risk surgery. The aim of the study was to integrate robotics technology into mandibular reconstruction surgery as it can reduce surgeons' workload and improve the accuracy and quality of the surgery. In this study, we first introduced a mandibular reconstruction surgery robotic system, which includes integrated surgery planning, an optical navigation system, and a robot-assisted operation. Second, we addressed novel mandibular reconstruction surgery that is aided by a multi-arm robot with an optical navigation system. Finally, we conducted an accuracy test, a skull model experiment, and an animal experiment to evaluate the robotic system. Experiments showed that the robot's mean placement error was 1.0205 mm, which was acceptable for clinical application. We will continue to study this point, however, and plan to reduce the error eventually to 1.00 mm. The robot ran smoothly and accurately. It was also able to perform fibular segment implantation, positioning, and auxiliary fixation during mandibular reconstruction surgery.

A mobile isocentric C-arm (Siemens PowerMobil) has been modified in our laboratory to include a large area flat-panel detector (in place of the x-ray image intensifier), providing multi-mode fluoroscopy and cone-beam computed tomography (CT) imaging capability. This platform represents a promising technology for minimally invasive, image-guided surgical procedures where precision in the placement of interventional tools with respect to bony and soft-tissue structures is critical. The image quality and performance in surgical guidance was investigated in pre-clinical evaluation in image-guided spinal surgery. The control, acquisition, and reconstruction system are described. The reproducibility of geometric calibration, essential to achieving high three-dimensional (3D) image quality, is tested over extended time scales (7 months) and across a broad range in C-arm angulation (up to 45 degrees), quantifying the effect of improper calibration on spatial resolution, soft-tissue visibility, and image artifacts. Phantom studies were performed to investigate the precision of 3D localization (viz., fiber optic probes within a vertebral body) and effect of lateral projection truncation (limited field of view) on soft-tissue detectability in image reconstructions. Pre-clinical investigation was undertaken in a specific spinal procedure (photodynamic therapy of spinal metastases) in five animal subjects (pigs). In each procedure, placement of fiber optic catheters in two vertebrae (L1 and L2) was guided by fluoroscopy and cone-beam CT. Experience across five procedures is reported, focusing on 3D image quality, the effects of respiratory motion, limited field of view, reconstruction filter, and imaging dose. Overall, the intraoperative cone-beam CT images were sufficient for guidance of needles and catheters with respect to bony anatomy and improved surgical performance and confidence through 3D visualization and verification of transpedicular trajectories and tool placement. Future investigation includes improvement in image quality, particularly regarding x-ray scatter, motion artifacts and field of view, and integration with optical tracking and navigation systems.