An improved method for assessing the technical accuracy of optical tracking systems for orthopaedic surgical navigation

Vermue

Robotics Computer Surgery

et al. 2022

Self Cite

Background:The intraoperative registration of the bones play a crucial role in image-based computer-assisted knee arthroplasty to achieve accurate implant placement and to create reliable stereotactic bone boundaries for robot-assisted surgical systems. Method:This study assessed the intraoperative registration accuracy on six intact fresh frozen cadavers.Results: Rotational errors around the mechanical axis were the largest, with a standard deviation of 1.2°and outliers up to 3.7°. The mean translational errors were lower than 1 mm, with outliers up to 1.5 mm. These errors were amplified to 2 mm for the registration-based reconstruction of the posterior bone surface at the resection levels. Conclusion:Given the cumulative behaviour of surgical errors, registration errors can affect the final implant positioning. Furthermore, inaccuracies in the reconstructed bone boundary directly affect the virtual stereotactic boundaries used in robotic-assisted surgery and can result in an incomplete resection or inadvertent soft tissue damage. K E Y W O R D Sanatomy, technology | INTRODUCTIONTotal knee arthroplasty (TKA) is a common and cost-effective surgical treatment for osteoarthritis of the knee joint. 1 However, 10%-20% of patients remain dissatisfied after TKA. 2 Malpositioning of the implant is associated with implant failure, and as a result, patient dissatisfaction. 3,4 To improve the accuracy of the implant position according to a preoperative plan, navigation and robotics have been introduced. 5 These technologies have proven to be successful in reducing the frequency of outliers of more than 3°, but errors up to these values still occur. [6][7][8][9][10] Navigation and robotic systems are in most cases using an optical tracking system (OTS) and a tracked pointer to determine the position and orientation of the femur and tibia with respect to the attached dynamic reference bases (DRB). 9,11,12 This intraoperative bone registration process is subject to a margin of error which affects the surgical accuracy. [11][12][13][14][15] The total operative accuracy is determined by a succession of inaccuracies in the following surgical steps: bone registration and matching of the surgical plan, tracking of the bones and the surgical objects in space, bone preparation and implant placement. During bone registration, the software model is matched with the patient's specific anatomy. As

Section: Discussionmentioning

confidence: 83%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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Accuracy of intraoperative bone registration and stereotactic boundary reconstruction during total knee arthroplasty surgery

Vermue

Robotics Computer Surgery

et al. 2022

Self Cite

Clinical Oral Implants Res

“…The clinical results in the present study indicated a stable implant accuracy under robotic assistance across a reasonable range of implant length and diameter. The high level of accuracy observed is dependent upon the convergence of three sets of factors: (i) the trueness of the tracking system of the robot (its tracking system, fiducial technology, and geometric design of the markers) (Herregodts et al, 2021); (ii) the registration process that allows the alignment of the digital and physical anatomy of the region of interest (Simpson et al, 2013); (iii) the ability of the visual control loop of the robot to compensate for patient movements (Dudek et al, 2022). Besides these technical aspects embedded in the design of the tested cobot, the skills of the surgeon to effectively co‐operate with the robot remain essential and so is the ability of the patient to stay still while the robotic drilling is performed.…”

Section: Discussionmentioning

confidence: 99%

Accuracy and safety of a haptic operated and machine vision controlled collaborative robot for dental implant placement: A translational study

Qiao

Shi

et al. 2023

ObjectivesMultiple generations of medical robots have revolutionized surgery. Their application to dental implants is still in its infancy. Co‐operating robots (cobots) have great potential to improve the accuracy of implant placement, overcoming the limitations of static and dynamic navigation. This study reports the accuracy of robot‐assisted dental implant placement in a preclinical model and further applies the robotic system in a clinical case series.Materials and MethodsIn model analyses, the use of a lock‐on structure at robot arm‐handpiece was tested in resin arch models. In a clinical case series, patients with single missing teeth or edentulous arch were included. Robot‐assisted implant placement was performed. Surgery time was recorded. Implant platform deviation, apex deviation, and angular deviation were measured. Factors influencing implant accuracy were analyzed.ResultsThe in vitro results showed that with a lock‐on structure, the mean (SD) of platform deviation, apex deviation, and angular deviation were 0.37 (0.14) mm, 0.44 (0.17) mm, and 0.75 (0.29)°, respectively. Twenty‐one patients (28 implants) were included in the clinical case series, 2 with arches and 19 with single missing teeth. The median surgery time for single missing teeth was 23 (IQ range 20–25) min. The surgery time for the two edentulous arches was 47 and 70 min. The mean (SD) of platform deviation, apex deviation, and angular deviation was 0.54 (0.17) mm, 0.54 (0.11) mm, and 0.79 (0.22)° for single missing teeth and for 0.53 (0.17) mm, 0.58 (0.17) mm, and 0.77 (0.26)° for an edentulous arch. Implants placed in the mandible had significantly larger apex deviation than those in the maxilla.ConclusionCobot‐assisted dental implant placement showed excellent positional accuracy and safety in both the in vitro study and the clinical case series. More technological development and clinical research are needed to support the introduction of robotic surgery in oral implantology. Trial registered in ChiCTR2100050885.

Evaluation of a calibration rig for stereo laparoscopes

et al. 2023

Background Accurate camera and hand‐eye calibration are essential to ensure high‐quality results in image‐guided surgery applications. The process must also be able to be undertaken by a nonexpert user in a surgical setting. Purpose This work seeks to identify a suitable method for tracked stereo laparoscope calibration within theater. Methods A custom calibration rig, to enable rapid calibration in a surgical setting, was designed. The rig was compared against freehand calibration. Stereo reprojection, stereo reconstruction, tracked stereo reprojection, and tracked stereo reconstruction error metrics were used to evaluate calibration quality. Results Use of the calibration rig reduced mean errors: reprojection (1.47 mm [SD 0.13] vs. 3.14 mm [SD 2.11], p‐value 1e−8), reconstruction (1.37 px [SD 0.10] vs. 10.10 px [SD 4.54], p‐value 6e−7), and tracked reconstruction (1.38 mm [SD 0.10] vs. 12.64 mm [SD 4.34], p‐value 1e−6) compared with freehand calibration. The use of a ChArUco pattern yielded slightly lower reprojection errors, while a dot grid produced lower reconstruction errors and was more robust under strong global illumination. Conclusion The use of the calibration rig results in a statistically significant decrease in calibration error metrics, versus freehand calibration, and represents the preferred approach for use in the operating theater.