Knowledge of vertebra location, shape, and orientation is crucial in many medical applications such as orthopedics or interventional procedures. Computed tomography (CT) offers a high contrast between bone and soft tissues, but automatic vertebra segmentation remains difficult. Hence, the wide range of shapes, aging, and degenerative joint disease alterations as well as the variety of pathological cases encountered in an aging population make automatic segmentation sometimes challenging. Besides, daily practice implies a need for affordable computation time. This paper aims to present a new automated vertebra segmentation method (using a first bounding box for initialization) for CT 3D data which tackles these problems. This method is based on two consecutive steps. The first one is a new coarse-to-fine method efficiently reducing the data amount to obtain a coarse shape of the vertebra. The second step consists in a hidden Markov chain (HMC) segmentation using a specific volume transformation within a Bayesian framework. Our method does not introduce any prior on the expected shape of the vertebra within the bounding box and thus deals with the most frequent pathological cases encountered in daily practice. We experiment this method on a set of standard lumbar, thoracic, and cervical vertebrae and on a public dataset, on pathological cases, and in a simple integration example. Quantitative and qualitative results show that our method is robust to changes in shapes and luminance and provides correct segmentation with respect to pathological cases.
The purpose of this study is to prove that 3D camera is better than 2D camera in terms of the burden to surgeons by physiological assessment in endoscopic surgery. During laparoscopic tasks, 128ch EEG was recorded and then the data was analyzed. Power in the beta bands was expressed as a percentage of the total power in each segment. In the space pointing task, significant differences between 2D and 3D were noted in the parietal cortex. In the parietal cortex, beta band patterns appeared more frequently in 2D than 3D. It means that the burden to the brain with 2D monitor is larger than with 3D. Other difference was noted in the ligation task. The frequency of beta band patterns was higher in the vision-parietal cortex in 3D. In conclusion when the 3D camera is used, laparoscopic surgery can be operated with fewer burdens to the brain. Further data collection and analysis is needed to physiologically assess the role of 3D video system in laparoscopic surgery.
Deep brain stimulation (DBS) is a surgical treatment which implants stimulating electrodes in deep brain structure and implanted pulse generators (IPG) into the chest. DBS has shown therapeutic benefits for chronic pain, Parkinson’s disease, tremor, and dystonia. In this paper, we present preliminary evaluation results of conventional stereotactic frame based DBS procedures in terms of elapsed time. The purpose is to build a basis on which a quantitative evaluation on efficiency of surgical robot systems for DBS is possible, and to identify what the benefits of using surgical robot systems in DBS are. For the purpose, we define surgical procedures for the conventional DBS and measure time for each procedure. Eight DBS cases are studied, and the evaluation results of averaged elapsed time are shown.
An expanding mosaic view is one of the possible solutions for narrow field of view during endoscopic surgery. The current work presents a system to create an expanding mosaic view of the video during laparoscopy where the laparoscope is held and moved by a customized robot arm.
Single photon emission computed tomography (SPECT) is a popular modality in clinic for liver function evaluation, but it is challenging for computerized segmentation and analysis of SPECT images. Most conventional technologies including mean shift and level set methods are not efficient due to weak contrast and ambiguous boundaries. We propose a new integrative model for liver function region segmentation in nuclear medicine. First, mean shift segmentation is improved by incorporating both space and color information. The enhanced mean shift is able to separate liver dysfunctional regions from their background. Second, the preparatory mean shift segmentation is employed to initialize a Hamilton-Jacobi level set model. It makes level set evolution nearby the objects of interest. Finally, we propose a new object indication function by considering the original nuclear medicine image as well as the relevant mean shift segmentation. This combinational indicator is effective to control level set segmentation. Otherwise, boundary leakage is inevitable. Experimental results on a set of clinical SPECT images confirm the effectiveness and robustness of this new integrative model.
In this paper, we propose a graphics processing unit-based efficient surgical algorithm for operating on a human liver by a cavitron ultrasonic surgical aspirator (CUSA) scalpel in a virtual environment built with polyhedral objects in Standard Triangulation Language format. First, using z-buffers of a human liver and a CUSA scalpel in a general-purpose graphics processing unit, we rapidly detect their intersections of rectangular parallelepipeds. Then, depending on the plastic, elastic, and viscous material properties of the operated portion of the liver, we determine the rectangular parallelepiped lengths. From that point, based on the correspondence between a vertex and pixel via the XY-image of the z-buffer, the corresponding vertices of the liver polyhedron are moved along the Z-axis of the z-buffer according to its extended or contracted length of rectangular parallelepipeds. By this function, the liver polyhedron can be efficiently and precisely deformed or cut by the CUSA polyhedron.
It is often required to hold an ultrasound probe for long time so that the moving target is maintained within the B-mode image, especially for minimally invasive interventions. Using a conventional 2D probe, the tracking out-of-plane motion is a challenging technique because in this case the target is missing from the image plane. In this paper, we propose a 3D tracking method for a probe holding robot based on the 2D B-mode image feedback. In order to track the out-of-plane motion, a template matching between the current image and the previously recorded 3D data is performed. In-plane motion is detected by a template matching in the plane. Essentially the tracking by visual information on the real soft tissue is difficult because of its deformation. However, our method is robust for a certain amount of the deformation. We have applied this method for an in-vivo experiment of human liver respiratory motion compensation and results show its effectiveness.
A robot assisted intubation system based on remote teleoperation is developed. The architecture and the system configuration are introduced. It is composed of master manipulator in hospital and slave manipulator in first aid site. When the ambulance equipped with this medical device arrived at the disaster site, doctors with specialized skills can stay in hospital and control the robot to carry out the intubation by remote teleoperation method. The proposed system solves the lack of doctor with specialized skills in the rescue work. To improve the effectiveness of the system and guarantee the safety of patients and medical staff at the same time, we analyze the articulation of the robotics arm, and optimized the parameters.
This paper presents an investigation on international and Korean standards related to evaluation of safety and performance in the robots for knee replacement surgery. The safety of the knee replacement robots can be evaluated in the biological, mechanical, electrical, emergency aspects. The performance can be evaluated by motion ability, clinical ability, and components but there are somewhat different items, depending on the types of the robots which can be classified by whether the robots perform autonomous task or surgeon-guided actuation. The relevant international and Korean standards are provided as a table, indices to evaluate safety and performance are defined, and test methods for evaluation are shortly discussed.
This work presents an intraoperative method for registration of 3D ultrasound images to surgical navigation systems. Unlike conventional methods that rely on pre-calibration of ultrasound probe in a laboratory environment using a calibration rig, the proposed method is designed to self-register with a tracking system in an operating room. It exploits intraoperative motion of the surgical instrument to compute the registration function instead of using the known geometry of a phantom structure. To reduce estimation errors arising from poor image quality and uncertainty of image-based position estimations, the pivotal constraint associated with minimally invasive surgeries is imposed as a positional correspondence between the imaging and tracking system. We demonstrated the registration of an ultrasound imaging device to an optical tracker and evaluated the accuracy in a water tank setup. This self-registration framework has potential contribution in the unification of ultrasound image-guidance and tracker-based surgical navigation systems. The ultimate goal is to combine ultrasound image-guidance and tracking systems as an integrated surgical navigation system.
This paper presents a novel method for evaluating a user’s feelings in a master–slave robotic surgical operation. By measuring brain activity, an engineer can quantify the user’s feelings during the operation from a cognitive science perspective. In contrast with conventional methods, the engineer can consider the user’s feelings in designing a robot with intuitive operability. The brain activity measurement method is well suited to not only surgical robots but also all master–slave robots. The objective of this paper is to determine the optimal distance between the slave and endoscope using brain activity measurement. We find that brain activity shows a significant peak when the user controls the virtual arm in a position matching the most natural hand-eye coordination.
Minimally invasive surgery (MIS) bring remarkable benefits such as reduced trauma, shorter hospital stay, less complication, and cosmetic treatment. In order to perform smoothly in MIS, dexterous surgical instruments are in urgent needs. This paper presents a 6-DOF dexterous manipulator for Single Port Access Surgery (SPAS). It is composed of four parts, 1-DOF linear motion joint, two 2-DOF bendable joints (segment1 and segment2), and 1-DOF rotational end effector. The two bendable segments with “Double Screw Drive (DSD) mechanism” structure can be actuated for arbitrary bending motion in any direction. Flexible shaft is used for power transmission. The distribution of the power transmission element in the manipulator was compared by using two different design configurations. In the first prototype, the flexible shaft was directly connected with each actuator in the manipulator. Compared with the first prototype, in the second prototype, flexible shafts are connected to the base of the manipulator. In order to pass the power to the distal of the manipulator, universal joints and slide unit are used for power transmission to pass through the proximal bendable segment. The improvement done with the design of the second prototype decreased the torque necessary to drive the flexible shafts during bending motion in surgical operations. Experiment results show that the second prototype of manipulator has enough range of movement for surgical intervention, the possibility of using the dexterous manipulator in the SPAS was discussed.
During a robot-assisted minimally invasive surgery, the surgeon controls the surgical instruments insides the patient’s body through teleoperation. For the surgeon, the endoscope and the surgical instruments insides the patient’s body are just like his/her own “eyes” and “hands” extended in space. Hence the motion alignment between the master control handles and the end effectors of the associated slave manipulators should be carefully designed so as to maximally coordinate the “hand” and the eye of the surgeon, which can give the surgeon the same feeling as carrying out an open surgery. However, for different types of master–slave minimally invasive surgical robots, how to design the master–slave motion aligning strategy to realize “How You Move Is What You See”, is still not answered in relative researches. In this paper, we will try to find an answer to this question.
Abstract Optimal component alignment in total knee arthroplasty has been associated with better functional outcome as well as improved implant longevity. The ability to align components optimally during minimally invasive (MIS) total knee replacement (TKR) has been a cause of concern. Computer navigation is a useful aid in achieving the desired alignment although it is limited by the error during the manual registration of landmarks. Our study aims to compare the registration process error between a standard and a MIS surgical approach. We hypothesized that performing the registration error via an MIS approach would increase the registration process error. Five fresh frozen lower limbs were routinely prepared and draped. The registration process was performed through an MIS approach. This was then extended to the standard approach and the registration was performed again. Two surgeons performed the registration process five times with each approach. Performing the registration process through the MIS approach was not associated with higher error compared to the standard approach in the alignment parameters of interest. This rejects our hypothesis. Image-free navigated MIS TKR does not appear to carry higher risk of component malalignment due to the registration process error. Navigation can be used during MIS TKR to improve alignment without reduced accuracy due to the approach.
Abstract Resection of a pelvic tumor is challenging because of its complex three-dimensional (3D) anatomy and deep-seated location with nearby vital structures. The resection is technically demanding if a custom implant is used for reconstruction of the bone defect as the surgeon needs to ensure the resection margin is sufficiently wide and the orientation of intended resection planes must match that of the custom implant. We describe a novel workflow of performing a partial acetabular resection in a patient with pelvic chondrosarcoma and reconstruction with a custom pelvic implant in a one-step operation. A multi-planar bone resection was virtually planned. A computer-aided design implant that both matched the bone defect and biomechanically evaluated was prefabricated with 3D printing technology. The 3D-printed patient-specific instruments (PSIs) were used to reproduce the same planned resection. The histology of the tumor specimen showed a clear resection margin. The errors of the achieved resection and implant position were deviating (1–4 mm) from the planned. The patient could walk unaided with a good hip function. No tumor recurrence and implant loosening were noted at 11 months after surgery. The use of this novel CT-based method for surgical planning, the engineering software for implant design and validation, together with 3D printing technology for implant and PSI fabrication makes it possible to generate a personalized, biomechanically evaluated implant for accurate reconstruction after a pelvic tumor resection in a one-step operation. Further study in a larger population is needed to assess the clinical efficacy of the workflow in complex bone tumor surgery.
This study describes computer simulation of blood flow and plaque progression pattern in a patient who underwent surgical treatment for infected carotid prosthetic tube graft using carotid-carotid cross-over bypass. The 3D blood flow is governed by the Navier-Stokes equations, together with the continuity equation. Mass transfer within the blood lumen and through the arterial wall is coupled with the blood flow and is modelled by the convection-diffusion equation. Low-density lipoprotein (LDL) transport in lumen of the vessel is described by Kedem-Katchalsky equations. The inflammatory process is solved using three additional reaction-diffusion partial differential equations. Calculation based on a computer simulation showed that flow distribution in the left carotid artery (CA) was around 40-50% of the total flow in the right common CA. Also, the left CA had higher pressure gradient after surgical intervention. Plaque progression simulation predicted development of the atherosclerotic plaque in the position of the right common CA and the left internal CA. A novel way of atherosclerotic plaque progression modelling using computer simulation shows a potential clinical benefit with significant impact on the treatment strategy optimization.
Surgery is characterized by complex tasks performed in stressful environments. To enhance patient safety and reduce errors, surgeons must be trained in environments that mimic the actual clinical setting. Rasmussen’s model of human behavior indicates that errors in surgical procedures may be skill-, rule-, or knowledge-based. While skill-based behavior and some rule-based behavior may be taught using box trainers and ex vivo or in vivo animal models, we posit that multimodal immersive virtual reality (iVR) that includes high-fidelity visual as well as other sensory feedback in a seamless fashion provides the only means of achieving true surgical expertise by addressing all three levels of human behavior. While the field of virtual reality is not new, realization of the goals of complete immersion is challenging and has been recognized as a Grand Challenge by the National Academy of Engineering. Recent technological advances in both interface and computational hardware have generated significant enthusiasm in this field. In this paper, we discuss convergence of some of these technologies and possible evolution of the field in the near term.
Abstract Purpose: To introduce easy and useful methods using 3D navigation system with skin-fixed dynamic reference frame (DRF) in anterior cervical surgery and to validate its accuracy. Methods: From September 2012 to May 2013, 31 patients underwent anterior cervical surgery and a total of 48 caspar distraction pins were inserted into each cervical vertebra. Every operation was performed using O-arm® navigation system with skin-fixed DRF. To validate the accuracy of these methods, a custom-made metal sleeve was used. In surgical field, through the metal sleeve, the tip of a navigation probe promptly contacts to the tip of caspar pin. We measured the vertical and horizontal distances and the angular deviation in sagittal plane between the caspar pin and the navigation probe on the virtual images and evaluated accuracy of navigation system with skin fixed DRF. Results: Total 31 (males 20, females 11) patients and 48 caspar pins were included in this study. The mean horizontal distance between the caspar pin and the navigation probe displayed in navigation monitor was 0.49 ± 0.71 mm. The mean vertical distance between the caspar pin and the navigation probe displayed in navigation monitor was 0.88 ± 0.93 mm. And the mean angular deviation in sagittal plane between the caspar pin and the navigation probe displayed in navigation monitor was 0.59 ± 0.55°. Conclusions: 3D navigation system with skin-fixed DRF in anterior cervical surgery is a simple and reliable method and it can be a helpful supplement to a spine surgeon’s judgement.
Objective: We developed a novel method of producing accurate range images of the velopharynx using a three-dimensional (3D) endoscope to obtain detailed measurements of velopharyngeal movements. The purpose of the present study was to determine the relationship between the distance from the endoscope to an object, elucidate the measurement accuracy along the temporal axes, and determine the degree of blurring when using a jig to fix the endoscope. Methods: An endoscopic measuring system was developed in which a pattern projection system was incorporated into a commercially available 3D endoscope. After correcting the distortion of the camera images, range images were produced using pattern projection to achieve stereo matching. Graph paper was used to measure the appropriate distance from the camera to an object, the mesial buccal cusp of the right maxillary first molar was measured to clarify the range image stability, and an electric actuator was used to evaluate the measurement accuracy along the temporal axes. Results: The measurement error was substantial when the distance from the camera to the subject was >6.5cm. The standard error of the 3D coordinate value produced from 30 frames was within 0.1mm (range, 0.01-0.08mm). The measurement error of the temporal axes was 9.16% in the horizontal direction and 9.27% in the vertical direction. Conclusion: The optimal distance from the camera to an object is <6.5cm. The present endoscopic measuring system can provide stable range images of the velopharynx when using an appropriate fixation method and enables quantitative analysis of velopharyngeal movements.
Primary and metastatic liver tumors constitute a significant challenge for contemporary medicine. Several improvements are currently being developed and implemented to advance image navigation systems for percutaneous liver focal lesion ablation in clinical applications at the diagnosis, planning and intervention stages. First, the automatic generation of an anatomically accurate parametric model of the preoperative patient liver was proposed in addition to a method to visually evaluate and make manual corrections. Second, a marker was designed to facilitate rigid registration between the model of the preoperative patient liver and the patient during treatment. A specific approach was implemented and tested for rigid mapping by continuously tracking a set of uniquely identified markers and by accounting for breathing motion, facilitating the determination of the optimal breathing phase for needle insertion into the liver tissue. Third, to overcome the challenge of tracking the absolute position of the planned target point, an intra-operative ultrasound (US) system was integrated based on the Public Software Library for UltraSound and OpenIGTLink protocol, which tracks breathing motion in a 2D time sequence of US images. Additionally, to improve the visibility of liver focal lesions, an approach to determine spatio-temporal correspondence between the US sequence and the 4D computed tomography (CT) examination was developed, implemented and tested. This proposed method of processing anatomical model, rigid registration approach and the implemented US tracking and fusion method were tested in 20 anonymized CT and in 10 clinical cases, respectively. The presented methodology can be applied and used with any older 2D US systems, which are currently commonly used in clinical practice.
