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Biomedical subjects

Yoshito Otake

Publications and source records attributed to Yoshito Otake.

17 recordsLinked to original sources
PubMed2006

Soft-tissue balance evaluation system for total hip arthroplasty by intraoperative contact pressure measurement at the hip joint.

We developed a system for measurement of contact pressure at the hip joint surfaces that enables checking of the artificial hip joint condition during surgery. First, we constructed the pressure sensor that forms the artificial joint. We installed eight small pressure sensors to the spherical head component, a part of the ball-socket joint. Next, we developed software for recording and visualizing the detected pressures that were recorded every 1 ms. The pressure distribution was displayed with the 3D computer graphics in real-time. The system enabled intuitive recognition of pressure direction 3-dimensions. Next, using the system, we conducted measurements during total hip arthroplasty. Although it requires some improvements in its measurement accuracy, the system allows real-time acquisition of information on the artificial hip joint in real-time. Further improvements of the calibration method should enable more accurate measurements. As a complete system, it will be a useful tool for selecting an appropriate implant that fits a patient's hip joint or for estimating the risk of complications after surgery.

Arthroplasty, Replacement, Hip↗
PubMed2006

Estimation of skeletal movement of human locomotion from body surface shapes using dynamic spatial video camera (DSVC) and 4D human model.

We have been developing a DSVC (Dynamic Spatial Video Camera) system to measure and observe human locomotion quantitatively and freely. A 4D (four-dimensional) human model with detailed skeletal structure, joint, muscle, and motor functionality has been built. The purpose of our research was to estimate skeletal movements from body surface shapes using DSVC and the 4D human model. For this purpose, we constructed a body surface model of a subject and resized the standard 4D human model to match with geometrical features of the subject's body surface model. Software that integrates the DSVC system and the 4D human model, and allows dynamic skeletal state analysis from body surface movement data was also developed. We practically applied the developed system in dynamic skeletal state analysis of a lower limb in motion and were able to visualize the motion using geometrically resized standard 4D human model.

Biomechanical Phenomena↗
PubMed2005

Data-fusion display system with volume rendering of intraoperatively scanned CT images.

In this study we have designed and created a data-fusion display that has enabled volumetric MIP image navigation using intraoperative C-arm CT data in the operating room. The 3D volumetric data reflecting a patient's inner structure is directly displayed on the monitor through video images of the surgical field using a 3D optical tracking system, a ceiling-mounted articulating monitor, and a small size video camera mounted at the back of the monitor. The system performance was validated in an experiment carried out in the operating room.

Computer Graphics↗
PubMed2005

Development of a navigation function for an endosocopic robot surgery system.

An endoscopic robot system that we reported at MMVR11 is able to perform various surgical procedures in the stomach by using two manipulators. However, it is difficult for surgeons to recognize the 3D location and the direction of the endoscope's tip in the abdominal region during robotic surgery. In this research, we have developed a navigation function that enables image-guided surgery by superimposing the patient's abdominal organ structure onto the endoscopic image. In this paper, we describe the overview of the navigation for the robot system and the result of an animal experiment done while applying the system.

Endoscopy↗
PubMed2005

Estimation of dislocation after total hip arthroplasty by 4-dimensional.

We constructed a 4-dimensional musculoskeletal model for patients who have undergone total hip arthroplasty (THA), which aimed to simulate the movement of the patient's inner body structure and estimate the complications that can arise with THA. The model reflects patient-specific characteristics of the bone geometry, implant alignment and hip movement. In order to estimate the direction of the muscle force and the length of the muscles, we developed a string-type muscle model that represents the route of the muscles. The strings expand and contract according to the movement of the origin and insertion location of the muscle. We developed models for the seven muscles related to movement of the hip joint. By using this model, clinicians will be able to predict the possibility of dislocation or recognize the actual causes of dislocation, as well as any possible influences the muscle may have on dislocation.

Arthroplasty, Replacement, Hip↗
PubMed2005

Analysis of masticatory muscle condition using the 4-dimensional muscle model for a patient with square mandible.

The present study was conducted to ascertain characteristics of mandibular movements in patients with SQM, observe the kinetics of masticatory muscles using a four-dimensional (4D) muscle model, and kinetically investigate the etiology of Square Mandible (SQM). As results, 1, In the maximum opening position, location of the condyle was beyond the articular tubercle for volunteer, but within the mandibular fossa for SQM patient. 2, While the temporal muscle of volunteer was markedly expanded, that of SQM patient was not. 3, In both volunteer and SQM during left lateral excursion, the right mandibular condyle moved to a position slightly before the lowest point of the articular tubercle. The 4D muscle model showed that the cause of limited mouth opening in SQM patient was insufficient expansion of the temporal muscle, and not dysfunction of the opening muscles. Insufficient expansion of the temporal muscle stresses the masseter muscle and leads to hypertrophy of the masseter muscle and hyperplasia of the mandibular angle, resulting in the unique facial configuration.

Adult↗
PubMed2005

Construction of a high-tech operating room for image-guided surgery using VR.

This project aimed to construct an operating room to implement high dimensional (3D, 4D) medical imaging and medical virtual reality techniques that would enable clinical tests for new surgical procedures. We designed and constructed such an operating room at Dai-san Hospital, the Jikei Univ. School of Medicine, Tokyo, Japan. The room was equipped with various facilities for image-guided, robot and tele- surgery. In this report, we describe an outline of our "high-tech operating room" and future plans.

Facility Design and Construction↗
PubMed2004

Four-dimensional model of the lower extremity after total hip arthroplasty.

We have developed a four-dimensional (4D) model of the lower extremities after total hip arthroplasty in patients. The model can aid in preventing complications such as dislocation and wearing of the sliding surface. The skeletal structure and implant alignment were obtained from CT data. We applied registration method using CAD data to estimate accurate implant alignment from scattered CT data. The reconstructed three-dimensional (3D) skeletal model was combined with motion capture data that were acquired by an optical tracking system. We displayed the patient's skeletal movement and analyzed several parameters that relate to complications. The patient's skeletal model was superimposed onto video footage that was taken by a synchronized and calibrated digital video camera. For validation of the measurement error in this system, we used open MRI to evaluate the relative movement between skin markers and bones. This system visually represents not only the 3D anatomical structure, but also 4D dynamic functions that include the time sequential transitions of components and their positions. The open MRI results indicated that the average error in hip angle was within 5 degrees for each static posture. This system enables clinicians to analyze patient's motions on the basis of individual differences. We found that our system was an effective tool in providing precise guidance of daily postoperative motions that was individualized for each patient. This system will be applicable for surgical planning, assessment of postoperative activities, and the development of new surgical techniques, materials, and prosthetic designs.

Adolescent↗
PubMed2004

A novel system of four-dimensional motion analysis after total hip arthroplasty.

We have developed a novel system of four-dimensional motion analysis after total hip arthroplasty (THA) that can aid in preventing dislocation by assessing safe range of motion for patients in several daily activities. This system uses skeletal structure data from CT and motion capture data from an infrared position sensor. A 3-D model reconstructed from CT data is combined with the motion capture data. Using this system, we analyzed hip motion when getting up from and sitting down in a chair or picking up an object while sitting in a chair in 17 patients (26 hips) who underwent THA. To assess the accuracy of this system's measurements, open MRI was used to evaluate positions of skin markers against bones in five healthy volunteers in various postures. No impingement between bones and/or implants was found in any subjects during any activities. However, mean angle at the point of maximum hip flexion was different for each patient. The open MRI results indicated that average error in hip angle of the present system was within 5 degrees for each static posture. The functional position of the pelvis during daily activities must be taken into account when assessing the real risk of dislocation. The present system enables dynamic analysis involving not only alignment of components and bones of each patient, but also individual differences in characteristics of daily motions. Further investigation using this system can help determine safe ranges of motion for preventing hip dislocation, improving the accuracy of individualized guidance for patients regarding postoperative activities.

Adolescent↗
PubMed2004

[Verification of precision by 4-dimensional analysis of mandibular movement].

PURPOSE: The 4-dimensional human body model that combines reconstructed 3-dimensional image data (CT and MRI) and exercise data of the human body is widely applied in the medical field. We have applied this technique to assess mandibular movement, particularly in dentistry, and developed a 4-dimensional system of analyzing mandibular movement. The aim of this study was to determine the accuracy of this analysis system. METHODS: A dry skull mandible was fixed at several mandibular positions and the skull-mandible relationship was measured at each position by two procedures: CT scanning was performed and a 3-dimensional image was reconstructed from image data that were regarded as true values; then, optical measurement markers attached to the dental arch were measured 3-dimensionally and calculated as positional measurement values. The measurement values were compared with the corresponding true values to identify measurement errors of the analysis system. RESULTS: The root-mean-square (RMS) errors of the 4-dimensional analysis system of mandibular movement were, on average, 0.41 mm and 0.43 degrees. CONCLUSIONS: These findings suggest that our 4-dimensional analysis system has sufficient measurement accuracy for mandibular movements.

English Abstract↗
PubMed2004

[Present and future developments of the virtual surgery and tele-virtual surgery system].

One of the applications available now in the medical field is the virtual surgery system. This system allows surgeons a safe place to master surgical techniques and to plan surgical procedures before the operation. To provide the system for use in a clinical situation, a soft tissue model and a force feedback device suited for the surgery is required. In this paper, we would like to introduce our virtual surgery system, which possesses a soft tissue model that can show accurate, real-time deformation and is equipped with a force feedback device that allows the user to experience the tactile sensations. In addition, we will introduce our tele-virtual surgery simulation system for training in the procedures used in robotic surgery.

Computer Graphics↗
PubMed2003

4-dimensional computer-based motion simulation after Total Hip Arthroplasty.

This paper represents a novel 4-dimensional(4D) computer-based motion simulation system for patients having had Total Hip Arthroplasty(THA). By constructing the skeletal model of the patient's lower extremity and measuring daily motions, we simulated the movement of the inner structures including the skeleton and the artificial joint. This system visually represents not only the 3-dimensional(3D) anatomical structure but also the 4-dimensional dynamic functions that represent the time sequential transitions of the position of each component. Clinicians can get detailed information of the movement of the hip joint quantitatively and give precise guidance for the patients with regard to postoperative daily motions. The measurement error was evaluated by performing experiments using OpenMRI and the results indicated sufficient accuracy of this system. We believe that this system enables clinicians to reveal the causes of complications after THA and encourages the development of new surgical techniques, materials. and designs of prostheses.

Arthroplasty, Replacement, Hip↗
PubMed2003

Four-dimensional analysis of mandibular movements with optical position measuring and real-time imaging.

Mandibular movement findings have not always been useful in clinical, even though measuring techniques have improved. This is because there is no method to evaluate condylar movement including the position of the temporal bone. In this study, we have attempted to apply 3-dimensional imaging to mandibular movement data, and have developed a 4-demensional analysis system representing mandibular movements. In this system, the mandibular movement can be observed in real-time by using the CT dataset from a volunteer. As a result the relationship between the mandibular movement and the anatomic structures becomes clear.

Adult↗
PubMed2003

Development of Dynamic Spatial Video Camera (DSVC) for 4D observation, analysis and modeling of human body locomotion.

We have developed an imaging system for free and quantitative observation of human locomotion in a time-spatial domain by way of real time imaging. The system is equipped with 60 computer controlled video cameras to film human locomotion from all angles simultaneously. Images are installed into the main graphic workstation and translated into a 2D image matrix. Observation of the subject from optional directions is able to be performed by selecting the view point from the optimum image sequence in this image matrix. This system also possesses a function to reconstruct 4D models of the subject's moving human body by using 60 images taken from all directions at one particular time. And this system also has the capability to visualize inner structures such as the skeletal or muscular systems of the subject by compositing computer graphics reconstructed from the MRI data set. We are planning to apply this imaging system to clinical observation in the area of orthopedics, rehabilitation and sports science.

Human Body↗
PubMed2003

Development of an endoscopic robotic system with two hands for various gastric tube surgeries.

This paper presents the first report on an endoscopic robot with two manipulators which performed surgical work to resect the mucosal layer of the stomach of pigs without penetrating the body surface. We designed and developed an endoscopic surgical robot system which possesses two arm shaped manipulators for various kinds of surgery in the gastric tubes. The distal part of the manipulator functions as forceps and they are able to hold and handle soft tissues through the cooperative efforts of the right and left arms. And it is also able to incise the gastric wall by holding an electronic scalpel (brought in from the instrument channel) with the manipulator on the right side while opening the sectioning plane on the left side which was take out. With this system we succeeded in the mucosal resection of a large portion of the stomach wall of a pig during experimental surgery. It can be said that this is a new approach robotic surgery in the gastric tube with this kind of surgical robot.

Animals↗
PubMed2003

Development of a data fusion system using color information for real-time intraoperative liver surface measurement.

The goal of our study is to develop a data fusion system, which enables surgeons to easily visualize the inner structures of elastic organs during open surgery. We chose the liver as the focus of this study due to its easily deformable nature and complex vascular structures. To do so, we propose using preoperative data and supplementary intraoperative data. We captured a sequence of liver surface data for the intraoperative data by using trinocular stereo and we applied them to the preoperative 3D model's surface. Then, we modified the model to fit the intraoperative liver condition and portrayed the model's inner structures. With this method, we could establish this system.

Animals↗