Preliminary Results of a New Illuminated Radiofrequency Ablation Catheter for the Treatment of Great Saphenous Vein Reflux Disease.

Introduction: In the current study, we present single surgeon experience of a new radiofrequency ablation system, the catheter, and the device. Patients and Methods: The new system, which comprises a generator and an intervally illuminated radiofrequency ablation catheter, was used for the treatment of 272 consecutive patients with chronic venous insufficiency of the great saphenous vein between November 2017 and October 2018. Mean age of the patients was 53.40 ± 11.91 years. Mean saphenous vein diameter was 8.51 ± 2.45 mm. Bilateral great saphenous vein reflux disease was present in 19% (51 cases) of the patients. At the end of the procedure, the closure of the great saphenous vein was confirmed with Doppler ultrasonography. Results: Procedures could be successfully performed in all, except 1 obese (BMI> 30 kg/m2) male patient. At the 3rd month, outpatient clinic follow-up control Doppler USG revealed successful ablation of the treated great saphenous vein in 260 patients (96%), whereas in 12 cases (4%), there was continuing reflux. The diameters of the saphenous veins in these patients ranged between 6.9 mm and 19.5 (mean: 10.68 ± 3.41) mm. Ten patients could be treated successfully with ablation with the same device controlled both at the interventional section as well as on the 3rd month outpatient clinic follow-up. The remaining patients underwent high ligation of the great saphenous vein. Paresthesia occurred in 1 patient and had been permanent. Hematoma occurred in a male patient and resolved spontaneously. Conclusion: Preliminary results of our new radiofrequency ablation device with illumination guidance for the treatment of great saphenous vein reflux disease indicated successful results with enhanced physician utilization, comfort, and reliability.

Improve the Detection Range of Semi-Active Laser Guidance System by Temperature Compensation of Four-Quadrant PIN Detector.

The detection range of a semi-active laser guidance system can deviate significantly from the design value over a wide ambient temperature range. In this paper, a mathematical model of the detection range of a semi-active laser guidance system is built and the main factors affecting the detection range are analyzed. The parameter responsivity, which shows significant change, is found by applying the ambient temperature stress to the four-quadrant PIN detector and its signal processing chain. The relationship between the maximum detection range and ambient temperature is established based on a given signal-to-noise ratio, which is necessary for reliable detection. The target temperature and tolerance are setup for real-time temperature compensation for the four-quadrant PIN detector. The ambient temperature stress is applied to the system under compensation to verify the effect of compensation. The experimental results show that the ratio of the maximum variation of the detection range to the design point is 6.9% after the compensation is implemented when the ambient temperature changes from -40 °C to 60 °C, which is improved by 13.2% compared to that without compensation.

UAV Flight and Landing Guidance System for Emergency Situations †.

Unmanned aerial vehicles (UAVs) with high mobility can perform various roles such as delivering goods, collecting information, recording videos and more. However, there are many elements in the city that disturb the flight of the UAVs, such as various obstacles and urban canyons which can cause a multi-path effect of GPS signals, which degrades the accuracy of GPS-based localization. In order to empower the safety of the UAVs flying in urban areas, UAVs should be guided to a safe area even in a GPS-denied or network-disconnected environment. Also, UAVs must be able to avoid obstacles while landing in an urban area. For this purpose, we present the UAV detour system for operating UAV in an urban area. The UAV detour system includes a highly reliable laser guidance system to guide the UAVs to a point where they can land, and optical flow magnitude map to avoid obstacles for a safe landing.

A laser mount probe holder facilitates fixation of the optimized ultrasound image and needle alignment in-plane to the ultrasound beam during ultrasound-guided peripheral nerve block.

Laser guidance facilitates needle alignment in-plane to the ultrasound beam. Once the ultrasound image is optimized, there is no further need to maneuver the probe. Therefore, we designed a laser mount probe holder prototype, and examined the ease of visualization of the needle tip using the laser mount probe holder. The needle brightness was quantitatively measured using an image analysis software. We found that the laser mount probe holder is useful, not only to visualize the needle tip in the ultrasound plane, but also to fix the best ultrasound image.

Comparison of laser guidance and freehand hook-wire for CT-guided preoperative localization of pulmonary nodules.

PURPOSE: In VATS surgery, precise preoperative localization is particularly crucial when dealing with small-diameter pulmonary nodules located deep within the lung parenchyma. The purpose of this study was to compare the efficacy and safety of laser guidance and freehand hook-wire for CT-guided preoperative localization of pulmonary nodules. METHODS: This retrospective study was conducted on 164 patients who received either laser guidance or freehand hook-wire localization prior to Uni-port VATS from September 1st, 2022 to September 30th, 2023 at The First Affiliated Hospital of Soochow University. Patients were divided into laser guidance group and freehand group based on which technology was used. Preoperative localization data from all patients were compiled. The localization success and complication rates associated with the two groups were compared. The risk factors for common complications were analyzed. RESULTS: The average time of the localization duration in the laser guidance group was shorter than the freehand group (p<0.001), and the average CT scan times in the laser guidance group was less than that in the freehand group (p<0.001). The hook-wire was closer to the nodule in the laser guidance group (p<0.001). After the localization of pulmonary nodules, a CT scan showed 14 cases of minor pneumothorax (22.58%) in the laser guidance group and 21 cases (20.59%) in the freehand group, indicating no statistical difference between the two groups (p=0.763). CT scans in the laser guidance group showed pulmonary minor hemorrhage in 8 cases (12.90%) and 6 cases (5.88%) in the freehand group, indicating no statistically significant difference between the two groups (p=0.119). Three patients (4.84%) in the laser guidance group and six patients (5.88%) in the freehand group had hook-wire dislodgement, showing no statistical difference between the two groups (p=0.776). CONCLUSION: The laser guidance localization method possessed a greater precision and less localization duration and CT scan times compared to the freehand method. However, laser guidance group and freehand group do not differ in the appearance of complications such as pulmonary hemorrhage, pneumothorax and hook-wire dislodgement.

Evaluation of Accuracy and Performance of a Novel, Fully Gantry Integrated 3D Laser System for Computed Tomography Guided Needle Placement: A Phantom Study.

The purpose of this phantom study was to compare the accuracy, speed and technical performance of CT guided needle placement using a conventional technique versus a novel, gantry integrated laser guidance system for both an expert and a novice. A total of 80 needle placements were performed in an abdominal phantom using conventional CT guidance and a laser guidance system. Analysis of pooled results of expert and novice showed a significant reduction of time (277 vs. 204 s, p = 0.001) and of the number of needle corrections (3.28 vs. 1.58, p < 0.001) required when using laser guidance versus conventional technique. No significant improvement in absolute (3.81 vs. 3.41 mm, p = 0.213) or angular deviation (2.85 vs. 2.18°, p = 0.079) was found. With either approach, the expert was significantly faster (conventional guidance: 207 s vs. 346 s, p < 0.001; laser guidance: 144 s vs. 264 s, p < 0.001) and required fewer needle corrections (conventional guidance: 4 vs. 3, p = 0.027; laser guidance: 2 vs. 1, p = 0.001) than the novice. The laser guidance system helped both the expert and the novice to perform CT guided interventions in a phantom faster and with fewer needle corrections compared to the conventional technique, while achieving similar accuracy.

Laser Target System in Combination with an Aiming Device for Percutaneous CT-Guided Interventions - An Accuracy Study.

RATIONALE AND OBJECTIVES: To evaluate the targeting accuracy of laser-guided punctures in combination with an aiming device for computed tomography (CT) interventions during in vitro experiments. MATERIALS AND METHODS: A total of 600 CT-guided punctures were performed using a laser target system, half of them with the additional help of an aiming device. Conically shaped targets in a plexiglass phantom were punctured. The planning CT data sets were acquired with 1.25, 2.5 and 5 mm slice thickness. Needle placement accuracy, as well as procedural time, was assessed. The Euclidean (ED) and normal distances (ND) were calculated at the target point. RESULTS: Using the aiming device, the accomplished mean ND at the target for the 1.25, 2.5 and 5 mm slice thickness was 1.76 mm (SD ± 0.92), 2.09 mm (SD ± 1.06) and 1.93 mm (SD ± 1.38), respectively. Without aiming device, the corresponding results were 2.55 mm (SD ± 1.42), 2.7 mm (SD ± 1.43) and 2.31 mm (SD ± 1.64). At a slice thickness of 1.25 mm and 2.5 mm, punctures with the aiming device were significantly more accurate for both the ED and ND as compared to the punctures without aiming device (p < 0.001). The mean time required to complete the procedure, including image acquisition, trajectory planning, the placement of 10 needles, and the control-CT scan was 24.8 min without and 29.8 min with the aiming device. CONCLUSION: The additional use of the aiming device in combination with the commercially available laser guidance system significantly increased the level of accuracy during this in vitro experiment compared to freehand passes.

Clinical evaluation of a fluoroscopic image-based laser guidance system in bone tumor surgery: A technical note.

This study presents a laser guidance system developed to enhance surgical accuracy and reduce radiation exposure in orthopedic surgeries. The system can project the actual position corresponding to the appointed position selected by the surgeon on a fluoroscopic image using a line laser and has laser projection ability to mark the corresponding point using a line laser. The surgeon does not have to perform anatomical marker placement for calibration. Three patients with bone tumors underwent surgeries using the laser guidance system, and the projection accuracy was evaluated by measuring the distance error between the appointed and laser-marking positions. The installation time, including calibration, was also assessed for clinical usability. The average projection accuracy in bone tumor surgery was 2.86 mm, and the average installation time was 7 min. These results demonstrate that the laser guidance system, with a projection error of <3 mm, could be useful in bone tumor surgeries.

Role of Laser Pointer in Budgeting Fluoroscopy-Time and Radiation Exposure.

BACKGROUND: Literature on radiation exposure with use of the mini C-arm and value of having built-in laser guidance is limited. The purpose of this study was to determine whether laser guidance use on a mini C-arm fluoroscopy unit can reduce radiation exposure. METHODS: Surgeons (N = 25) performed the same simulated surgical task, which involved obtaining "perfect circle" views of 2 cannulated screws placed into a cadaveric wrist, done with and without C-arm laser guidance. The testing order was randomized. Main outcomes were time to complete the task, number of shots required to complete the task, number of blank shots taken, radiation exposure, total dose area product (DAP), and total exposure time. RESULTS: Laser guidance significantly reduced the percentage of surgeons who took blank shots, from 88% of the group without the laser to 12% of the group with the laser, and decreased the total average blank shots in the group from 3.5 to 0.1. While we found laser guidance led to shorter time to complete the task, decreased shots taken, and decreased exposure time and DAP, these findings only approached significance. CONCLUSION: While debate continues regarding whether mini or standard C-arm is safest, it is clear that decreasing the overall number of exposures limits potential adverse effects. Our study demonstrated that when using a mini C-arm, laser guidance decreases the number of exposures required to capture an image. These findings warrant a larger study to define the specific exposure savings and indicate potential benefit of mini C-arm use with laser guidance.

Fluoroscopic images-based aiming and targeting system with two line lasers for insertion guidance of interlocking screw.

PURPOSE: Minimally invasive surgery is widely used for managing fractures; however, it is difficult to determine the exact screwing position of intramedullary nails inserted into bone. To address this problem, we developed the aiming and targeting system by laser (ATLAS) using two line lasers to mark the position of the surgical tool directly on the skin. METHODS: ATLAS consists of a laser module, controller, personal computer, and display device. The laser module is fixed to the intensifier side of the C-arm. Calibration with dedicated markers is required prior to using the system. After calibration, the laser modules can mark the selected point on a fluoroscopic image acquired with the C-arm as the intersection of the two line lasers on the skin. RESULTS: To verify the effectiveness of ATLAS, marking accuracy was measured. The average control error of the device itself was 0.57 mm. In the experimental setting using C-arm fluoroscopy, the accuracy was within 1.5 mm at 23 of the 25 measurement points and within 3 mm at the remaining two points. CONCLUSION: ATLAS shows the corresponding points in real space with respect to fluoroscopic images using cross-points of lasers. The proposed method is clinically useful to aid the insertion of interlocking screws in minimally invasive surgeries for bone fractures. We believe that ATLAS enables more accurate marking through C-arm fluoroscopy and is more convenient, and it can thus be applied in various orthopedic surgeries.

CIGuide: in situ augmented reality laser guidance.

PURPOSE : A robotic intraoperative laser guidance system with hybrid optic-magnetic tracking for skull base surgery is presented. It provides in situ augmented reality guidance for microscopic interventions at the lateral skull base with minimal mental and workload overhead on surgeons working without a monitor and dedicated pointing tools. METHODS : Three components were developed: a registration tool (Rhinospider), a hybrid magneto-optic-tracked robotic feedback control scheme and a modified robotic end-effector. Rhinospider optimizes registration of patient and preoperative CT data by excluding user errors in fiducial localization with magnetic tracking. The hybrid controller uses an integrated microscope HD camera for robotic control with a guidance beam shining on a dual plate setup avoiding magnetic field distortions. A robotic needle insertion platform (iSYS Medizintechnik GmbH, Austria) was modified to position a laser beam with high precision in a surgical scene compatible to microscopic surgery. RESULTS : System accuracy was evaluated quantitatively at various target positions on a phantom. The accuracy found is 1.2 mm ± 0.5 mm. Errors are primarily due to magnetic tracking. This application accuracy seems suitable for most surgical procedures in the lateral skull base. The system was evaluated quantitatively during a mastoidectomy of an anatomic head specimen and was judged useful by the surgeon. CONCLUSION : A hybrid robotic laser guidance system with direct visual feedback is proposed for navigated drilling and intraoperative structure localization. The system provides visual cues directly on/in the patient anatomy, reducing the standard limitations of AR visualizations like depth perception. The custom- built end-effector for the iSYS robot is transparent to using surgical microscopes and compatible with magnetic tracking. The cadaver experiment showed that guidance was accurate and that the end-effector is unobtrusive. This laser guidance has potential to aid the surgeon in finding the optimal mastoidectomy trajectory in more difficult interventions.

Laser Guidance in C-Arm Cone-Beam CT-Guided Radiofrequency Ablation of Osteoid Osteoma Reduces Fluoroscopy Time.

PURPOSE: To assess whether laser guidance can reduce fluoroscopy and procedure time of cone-beam computed tomography (CBCT)-guided radiofrequency (RF) ablations of osteoid osteoma compared to freehand CBCT guidance. MATERIALS AND METHODS: 32 RF ablations were retrospectively analyzed, 17 laser-guided and 15 procedures using the freehand technique. Subgroup selection of 18 ablations in the hip-pelvic region with a similar degree of difficulty was used for a direct comparison. Data are presented as median (ranges). RESULTS: Comparison of all 32 ablations resulted in fluoroscopy times of 365 s (193-878 s) for freehand and 186 s (75-587 s) for laser-guided procedures (p = 0.004). Corresponding procedure times were 56 min (35-97 min) and 52 min (30-85 min) (p = 0.355). The subgroup showed comparable target sizes, needle path lengths, and number of scans between groups. Fluoroscopy times were lower for laser-guided procedures, 215 s (75-413 s), compared to 384 s (193-878 s) for freehand (p = 0.012). Procedure times were comparable between groups, 51 min (30-72 min) for laser guidance and 58 min (35-79 min) for freehand (p = 0.172). CONCLUSION: Adding laser guidance to CBCT-guided osteoid osteoma RF ablations significantly reduced fluoroscopy time without increasing procedure time. LEVEL OF EVIDENCE: Level 4, case series.

The Use of Laser Guidance Reduces Fluoroscopy Time for C-Arm Cone-Beam Computed Tomography-Guided Biopsies.

PURPOSE: When using laser guidance for cone-beam computed tomography (CBCT)-guided needle interventions, planned needle paths are visualized to the operator without the need to switch between entry- and progress-view during needle placement. The current study assesses the effect of laser guidance during CBCT-guided biopsies on fluoroscopy and procedure times. MATERIALS AND METHODS: Prospective data from 15 CBCT-guided biopsies of 8-65 mm thoracic and abdominal lesions assisted by a ceiling-mounted laser guidance technique were compared to retrospective data of 36 performed CBCT-guided biopsies of lesions >20 mm using the freehand technique. Fluoroscopy time, procedure time, and number of CBCT-scans were recorded. All data are presented as median (ranges). RESULTS: For biopsies using the freehand technique, more fluoroscopy time was necessary to guide the needle onto the target, 165 s (83-333 s) compared to 87 s (44-190 s) for laser guidance (p < 0.001). Procedure times were shorter for freehand-guided biopsies, 24 min versus 30 min for laser guidance (p < 0.001). CONCLUSION: The use of laser guidance during CBCT-guided biopsies significantly reduces fluoroscopy time.

The application of robotics to microlaryngeal laser surgery.

OBJECTIVES/HYPOTHESIS: To evaluate the performance of human subjects, using a prototype robotic micromanipulator controller in a simulated, microlaryngeal operative setting. STUDY DESIGN: Observational cross-sectional study. METHODS: Twenty-two human subjects with varying degrees of laser experience performed CO2 laser surgical tasks within a simulated microlaryngeal operative setting using an industry standard manual micromanipulator (MMM) and a prototype robotic micromanipulator controller (RMC). Accuracy, repeatability, and ablation consistency measures were obtained for each human subject across both conditions and for the preprogrammed RMC device. RESULTS: Using the standard MMM, surgeons with >10 previous laser cases performed superior to subjects with fewer cases on measures of error percentage and cumulative error (P = .045 and .03, respectively). No significant differences in performance were observed between subjects using the RMC device. In the programmed (P/A) mode, the RMC performed equivalently or superiorly to experienced human subjects on accuracy and repeatability measures, and nearly an order of magnitude better on measures of ablation consistency. The programmed RMC performed significantly better for repetition error when compared to human subjects with <100 previous laser cases (P = .04). CONCLUSIONS: Experienced laser surgeons perform better than novice surgeons on tasks of accuracy and repeatability using the MMM device but roughly equivalently using the novel RMC. Operated in the P/A mode, the RMC performs equivalently or superior to experienced laser surgeons using the industry standard MMM for all measured parameters, and delivers an ablation consistency nearly an order of magnitude better than human laser operators. LEVEL OF EVIDENCE: NA.

Integrated laser-guided CT biopsy.

The diagnostic yield of computed tomography (CT)-guided biopsies is dependent on accurate needle insertion. A laser-assisted angle selection system was custom fabricated and used during a CT-guided lung biopsy. Off-target error was measured comparing standard methods to the laser method while pointing towards the target from the skin. The difference between the planned angle and selected angle using the laser-assisted system was 2°, improved from 12° with the standard method. Although yet to be confirmed, laser-assisted angle selection systems may improve the accuracy of needle placement, which may translate into improved outcomes for certain needle based procedures.