The advent of 3D endoscope has revolutionized the field of industrial and medical inspection. It allows visual examination of inaccessible areas like underground pipes and human cavity. Miniature-sized objects like kidney stone and industrial waste products like slags can easily be monitored using 3D endoscope. In this paper, we present a technique to track small objects in 3D endoscopic vision using feature detectors. The proposed methodology uses the input of the operator to segment the target in order to extract reliable and stable features. Grow-cut algorithm is used for interactive segmentation to segment the object in one of the frames and later on, sparse correspondence is performed using SURF feature detectors. SURF feature detection based tracking algorithm is extended to track the object in the stereo endoscopic frames. The evaluation of the proposed technique is done by quantitatively analyzing its performance in two ex vivo environment and subjecting the target to various conditions like deformation, change in illumination, and scale and rotation transformation due to movement of endoscope.
A new approach for safe planning transfer using semi-automatically adjustable instrument guides, by Jeromin et al. MRCAS (2018) e1907
Accurate planning transfer is a prerequisite for successful operative care. For different applications, diverse computer‐assisted systems have been developed and clinically evaluated. This paper presents the implementation and evaluation of a new modular concept. The approach is based on passive application specific kinematics that are semi‐automatically adjusted using a universal hand‐held computer controlled Smart Screw Driver.
The system was realized for pedicle screw instrumentation and evaluated according to IEC 60601‐1‐6 (usability engineering). The accuracies of the drill holes achieved were comparable with robotic approaches, while operation time and radiation were reduced compared with conventional operation techniques. The adjustment procedure has proven high learnability and user satisfaction.
The next step will be optimization of the kinematic structure and fixation to the patient in order to increase accuracies of planning transfer as well as evaluation of the overall system by medical staff in preclinical and clinical studies.
Since the early 1970s, total knee arthroplasties have undergone many changes in both their design and their surgical instrumentation. It soon became apparent that to improve prosthesis durability, it was essential to have instruments which allowed them to be fitted reliably and consistently. Despite increasingly sophisticated surgical techniques, preoperative objectives were only met in 75% of cases, which led to the development, in the early 1990s, in Grenoble (France), of computer-assisted orthopaedic surgery for knee prosthesis implantation. In the early 2000s, many navigation systems emerged, some including pre-operative imagery (“CT-based”), others using intra-operative imagery (“fluoroscopy-based”), and yet others with no imagery at all (“imageless”), which soon became the navigation “gold standard”. They use an optoelectronic tracker, markers which are fixed solidly to the bones and instruments, and a navigation workstation (computer), with a control system (e.g. pedal). Despite numerous studies demonstrating the benefit of computer navigation in meeting preoperative objectives, such systems have not yet achieved the success they warrant, for various reasons we will be covering in this article. If the latest navigation systems prove to be as effective as the older systems, they should give this type of technology a well-deserved boost.
Feasibility and accuracy of computer-assisted individual drill guide template for minimally invasive lumbar pedicle screw placement trajectory, Wang, Hongwei et al. Injury (2018) published ahead of print.
To discuss the feasibility and accuracy of a specific computer-assisted individual drill guide template (CIDGT) for minimally invasive lumbar pedicle screw placement trajectory (MI-LPT) through a bovine cadaveric experimental study.
A 3-D reconstruction model, including lumbar vertebras (L1-L5), was generated, and the optimal MI-LPTs were determined. A drill guide template with a surface made of the antitemplate of the vertebral surface, including the spinous process and the entry point vertebral surface, was created by reverse engineering and rapid prototyping techniques. Then, MI-LPTs were determined by the drill guide templates, and the trajectories made by K-wires were observed by postoperative CT scan.
General Hospital of Shenyang Military Area Command of Chinese PLA.
In total, 150 K-wires for MI-LPTs were successfully inserted into L1-L5. The required mean time and fluoroscopy times between fixation of the template to the spinous process, entry point vertebral surface, and insertion of the K-wires for minimally invasive lumbar pedicle screw placement trajectories into each vertebra were 79.4 ± 15.0 seconds and 2.1 ± 0.8 times. There were no significant differences between the preoperative plan and postoperative assessment in the distance from the puncture to the midline and inclination angles according to the different levels (P > 0.05, respectively). The mean deviation between the preoperative plan and postoperative assessment in the distance from the puncture to the midline and inclination angles were 0.8 ± 0.5 mm and 0.9 ± 0.5°, respectively.
The potential use of the novel CIDGT, which was based on the unique morphology of the lumbar vertebra to place minimally invasive lumbar pedicle screws, is promising and could prevent too much radiation exposure intraoperatively.
A head-mounted display may include a display system and an optical system in a housing. The display system may have a pixel array that produces light associated with images. The display system may also have a linear polarizer through which light from the pixel array passes and a quarter wave plate through which the light passes after passing through the quarter wave plate. The optical system may be a catadioptric optical system having one or more lens elements. The lens elements may include a plano-convex lens and a plano-concave lens. A partially reflective mirror may be formed on a convex surface of the plano-convex lens. A reflective polarizer may be formed on the planar surface of the plano-convex lens or the concave surface of the plano-concave lens. An additional quarter wave plate may be located between the reflective polarizer and the partially reflective mirror.