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.
Patient-specific quantitative assessments of muscle mass and biomechanical musculoskeletal simulations require segmentation of the muscles from medical images. The objective of this work is to automate muscle segmentation from CT data of the hip and thigh.
We propose a hierarchical multi-atlas method in which each hierarchy includes spatial normalization using simpler pre-segmented structures in order to reduce the inter-patient variability of more complex target structures.
The proposed hierarchical method was evaluated with 19 muscles from 20 CT images of the hip and thigh using the manual segmentation by expert orthopedic surgeons as ground truth. The average symmetric surface distance was significantly reduced in the proposed method (1.53 mm) in comparison with the conventional method (2.65 mm).
We demonstrated that the proposed hierarchical multi-atlas method improved the accuracy of muscle segmentation from CT images, in which large inter-patient variability and insufficient contrast were involved.
Object. Utilization of pedicle screws (PS) for spine stabilization is common in spinal surgery. With reliance on visual inspection of anatomical landmarks prior to screw placement, the free-hand technique requires a high level of surgeon skill and precision. Three-dimensional (3D) computer-assisted virtual neuronavigation improves the precision of PS placement and minimize steps. Methods. Twenty-three patients with degenerative, traumatic, or neoplastic pathologies received treatment via a novel three-step PS technique that utilizes a navigated power driver in combination with virtual screw technology. 1) Following visualization of neuroanatomy using intraoperative CT, a navigated 3-mm match stick drill bit was inserted at anatomical entry point with screen projection showing virtual screw. 2) Navigated Stryker Cordless Driver with appropriate tap was used to access vertebral body through pedicle with screen projection again showing virtual screw. 3) Navigated Stryker Cordless Driver with actual screw was used with screen projection showing the same virtual screw. One hundred and forty-four consecutive screws were inserted using this three-step, navigated driver, virtual screw technique. Results. Only 1 screw needed intraoperative revision after insertion using the three-step, navigated driver, virtual PS technique. This amounts to a 0.69% revision rate. One hundred percent of patients had intraoperative CT reconstructed images to confirm hardware placement. Conclusions. Pedicle screw placement utilizing the Stryker-Ziehm neuronavigation virtual screw technology with a three step, navigated power drill technique is safe and effective.
In this paper we present novel solutions to support the application of computer assisted surgical interventions in which optical surgical navigation systems based on stereo cameras are used. The objective is to improve both the pre-operative setup and the intra-operative use of the navigation system. Following a short introduction describing the potential for improvements of existing navigation systems new approaches and the components to implement them are described. The pre-operative alignment of the stereo camera is made easier by attaching a small graphic display to its tripod which can show how much of the operating area is covered by the measurement volume of the camera. The intra-operative application is improved by a mechanism for motorized camera motions in order to follow the position of surgical instruments. Furthermore a small display can be attached to a surgical instrument which clearly indicates to the surgeon how to guide the instrument in order to stay on the planned trajectory.
This article presents a hardware/software simulation environment suitable for anytime/anywhere surgical skills training. It blends the advantages of physical hardware and task analogs with the flexibility of virtual environments. This is further enhanced by a web-based implementation of training feedback accessible to both trainees and trainers. Our training system provides a self-paced and interactive means to attain proficiency in basic tasks that could potentially be applied across a spectrum of trainees from first responder field medical personnel to physicians. This results in a powerful training tool for surgical skills acquisition relevant to helping injured warfighters.
For guidance of orthopedic surgery, the registration of preoperative images and corresponding surgical plans with the surgical setting can be of great value. Ultrasound (US) is an ideal modality for surgical guidance, as it is non-ionizing, real time, easy to use, and requires minimal (magnetic/radiation) safety limitations. By extracting bone surfaces from 3D freehand US and registering these to preoperative bone models, complementary information from these modalities can be fused and presented in the surgical realm.
A partial bone surface is extracted from US using phase symmetry and a factor graph-based approach. This is registered to the detailed 3D bone model, conventionally generated for preoperative planning, based on a proposed multi-initialization and surface-based scheme robust to partial surfaces.
36 forearm US volumes acquired using a tracked US probe were independently registered to a 3D model of the radius, manually extracted from MRI. Given intraoperative time restrictions, a computationally efficient algorithm was determined based on a comparison of different approaches. For all 36 registrations, a mean (± SD) point-to-point surface distance of 0.57(±0.08)mm was obtained from manual gold standard US bone annotations (not used during the registration) to the 3D bone model.
A registration framework based on the bone surface extraction from 3D freehand US and a subsequent fast, automatic surface alignment robust to single-sided view and large false-positive rates from US was shown to achieve registration accuracy feasible for practical orthopedic scenarios and a qualitative outcome indicating good visual image alignment.
Accurate cervical screw insertion is of paramount importance considering the risk of damage to adjacent vital structures. Recent research in 3-dimensional (3D) technology describes the advantage of patient-specific drill guides for accurate screw positioning, but consensus about the optimal guide design and the accuracy is lacking.
To find the optimal design and to evaluate the accuracy of individualized 3D-printed drill guides for lateral mass and pedicle screw placement in the cervical and upper thoracic spine.
Five Thiel-embalmed human cadavers were used for individualized drill-guide planning of 86 screw trajectories in the cervical and upper thoracic spine. Using 3D bone models reconstructed from acquired computed tomography scans, the drill guides were produced for both pedicle and lateral mass screw trajectories. During the study, the initial minimalistic design was refined, resulting in the advanced guide design. Screw trajectories were drilled and the realized trajectories were compared to the planned trajectories using 3D deviation analysis.
The overall entry point and 3D angular accuracy were 0.76 ± 0.52 mm and 3.22 ± 2.34°, respectively. Average measurements for the minimalistic guides were 1.20 mm for entry points, 5.61° for the 3D angulation, 2.38° for the 2D axial angulation, and 4.80° for the 2D sagittal angulation. For the advanced guides, the respective measurements were 0.66 mm, 2.72°, 1.26°, and 2.12°, respectively.
The study ultimately resulted in an advanced guide design including caudally positioned hooks, crosslink support structure, and metal inlays. The novel advanced drill guide design yields excellent drilling accuracy.
Open reduction and internal fixation of pelvic fractures could restore the stability of the pelvic ring, but there were several problems. Minimally invasive closed reduction cannulated screw treatment of pelvic fractures has lots advantages. However, how to insert the cannulated screw safely and effectively to achieve a reliable fixation were still hard for orthopedist. Our aim was to explore the significance of 3D printing technology as a new method for minimally invasive cannulated screw treatment of unstable pelvic fracture.
One hundred thirty-seven patients with unstable pelvic fractures from 2014 to 2016 were retrospectively analyzed. Based on the usage of 3D printing technology for preoperative simulation surgery, they were assigned to 3D printing group (n = 65) and control group (n = 72), respectively. These two groups were assessed in terms of operative time, intraoperative fluoroscopy, postoperative reduction effect, fracture healing time, and follow-up function. The effect of 3D printing technology was evaluated through minimally invasive cannulated screw treatment.
There was no significant difference in these two groups with respect to general conditions, such as age, gender, fracture type, time from injury to operation, injury cause, and combined injury. Length of surgery and average number of fluoroscopies were statistically different for 3D printing group and the control group (p < 0.01), i.e., 58.6 vs. 72.3 min and 29.3 vs. 37 min, respectively. Using the Matta radiological scoring systems, the reduction was scored excellent in 21/65 cases (32.3%) and good in 30/65 cases (46.2%) for the 3D printing group, versus 22/72 cases (30.6%) scored as excellent and 36/72 cases (50%) as good for the control group. On the other hand, using the Majeed functional scoring criteria, there were 27/65 (41.5%) excellent and 26/65 (40%) good cases for the 3D printing group in comparison to 30/72 (41.7%) and 28/72 (38.9%) cases for the control group, respectively. This suggests no significant difference between these two groups about the function outcomes.
Full reduction and proper fixation of the pelvic ring and reconstruction of anatomical morphology are of great significance to patients’ early functional exercise and for the reduction of long-term complications. This retrospective study has demonstrated the 3D printing technology as a potential approach for improving the diagnosis and treatment of pelvic fractures.
Spatial positioning accuracy is a key issue in a computer-assisted orthopaedic surgery (CAOS) system. Since intraoperative fluoroscopic images are one of the most important input data to the CAOS system, the quality of these images should have a significant influence on the accuracy of the CAOS system. But the regularities and mechanism of the influence of the quality of intraoperative images on the accuracy of a CAOS system have yet to be studied.Two typical spatial positioning methods – a C-arm calibration-based method and a bi-planar positioning method – are used to study the influence of different image quality parameters, such as resolution, distortion, contrast and signal-to-noise ratio, on positioning accuracy. The error propagation rules of image error in different spatial positioning methods are analyzed by the Monte Carlo method.Correlation analysis showed that resolution and distortion had a significant influence on spatial positioning accuracy. In addition the C-arm calibration-based method was more sensitive to image distortion, while the bi-planar positioning method was more susceptible to image resolution. The image contrast and signal-to-noise ratio have no significant influence on the spatial positioning accuracy. The result of Monte Carlo analysis proved that generally the bi-planar positioning method was more sensitive to image quality than the C-arm calibration-based method.The quality of intraoperative fluoroscopic images is a key issue in the spatial positioning accuracy of a CAOS system. Although the 2 typical positioning methods have very similar mathematical principles, they showed different sensitivities to different image quality parameters. The result of this research may help to create a realistic standard for intraoperative fluoroscopic images for CAOS systems.
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.