Yoshihiro Muragaki

Volumegraph (Overlaid three-dimensional image-guided navigation). Clinical application of augmented reality in neurosurgery

OBJECTIVEnWe have developed an overlaid three-dimensional image (Volumegraph)-guided navigation system that allows navigation during operative procedures. The three-dimensional image is superimposed on the patients head and body via a semi-transparent mirror. The Volumegraph can display three-dimensional images in the air by a light beam which is based on CT/MRI.nnnMETHODnThe system consists of a Volumegraph (thin plate of three-dimensional recorded medium), a Volumegraphscope and an original designed triangular-shaped marker system for registration. The three-dimensional data obtained from CT and MRI before the operation were processed by a computer. Such image data are applied for preoperative investigation to recognize the three-dimensional structure of organs and tumor. These reconstructed three-dimensional images were superimposed and registered at the patients head according to a fiducial marker (registration). Then the operator can operate with this three-dimensional-image-guided navigation system.nnnRESULTSnBased on clinical application in 7 cases, the system was found to be advantageous because the surgical procedures could be navigated easily by augmented reality in the surgical field. Invisible parts of the surgical field were supplemented with the overlaid three-dimensional images (Volumegraph) as if it were the virtual operative field. At another time, spatial positioning and overlaid visualization by the Volumegraph was useful for identifying anatomical structures and functional location in the image.nnnCONCLUSIONnThis preliminary study of overlaid three-dimensional-image-guided navigation demonstrated its clinical usefulness. The application of augmented reality in the surgical field makes it possible to do a neurosurgical intervention easily and accurately.

Identification of the Pyramidal Tract by Neuronavigation Based on Intraoperative Diffusion-Weighted Imaging Combined with Subcortical Stimulation

Background/Aims: To identify the pyramidal tract by neuronavigation based on intraoperative diffusion-weighted imaging (iDWI) combined with subcortical stimulation. Methods: Seven patients with brain tumors near the deep white matter underwent resection surgery using neuronavigation based on iDWI to visualize white matter bundles. Subcortical electrical stimulation was performed and electromyography was measured at the extremities when surgical manipulation came near the position corresponding to the depicted bundle. We validated the bundle depicted on iDWI by considering the responses to subcortical stimulation and the distance between the stimulation site and the depicted bundle. Results: Positive motor-evoked potentials were detected in 5 of 7 patients (8 stimulations) and the distance from the stimulation site to the depicted bundle was 0–4.7 mm (mean ± SD, 1.4 ± 2.1 mm). Negative (no) responses were obtained in all patients when the distance was more than 5 mm. The neuronavigation system had an average error of 0.79 ± 0.25 mm and a maximum error of 2.0 mm (n = 16). Conclusion: Neuronavigation based on iDWI combined with subcortical stimulation allowed surgeons to identify the pyramidal tract and avoid inadvertent injury. Our findings demonstrate that the white matter bundles depicted by iDWI can contain the pyramidal tract.

Remote-controlled laparoscope manipulator system, Naviot™, for endoscopic surgery

Abstract A remote-controlled laparoscope manipulator system, Naviot™ (Hitachi), is newly developed and introduced to a laparoscopic cholecystectomy for seven patients. This system consists of a specific laparoscope with a zoom lens, a flexible arm, an actuator, a five-bar linkage mechanism, and a hand controller. A surgeon can easily use the zoom lens and move the laparoscope into the eight directions by pushing the buttons of a hand controller. The zoom can be 5.07 magnifications. The moving range is 45° in the horizontal directions and 25° in the vertical ones. All procedures were performed safely and smoothly. We believe that this new system is feasible in clinical use and enables surgeons to perform “solo-surgery” in the near future.

Development of an articulating ultrasonically activated device for laparoscopic surgery

BackgroundUltrasonically activated devices (USADs) offer excellent coagulating dissection performance and are broadly used, particularly in endoscopic operations. Traditional USADs, however, have fixed linear shape and are thus limited in the directions from which organs can be approached. We have developed a small USAD transducer attached to the tip of an articulating device, offering a new kind of USAD in which the tip can bend as desired. We describe herein an evaluation of the coagulating dissection performance of this new articulating USAD and an in vivo confirmation of clinical usefulness.MethodsTo evaluate coagulating dissection performance, we compared coagulating shearing on porcine splenic arteries between the articulating USAD and a Harmonic Scalpel II (HSII), representing a traditional USAD. Changing the amplitude of vibration between 60xa0μm and 80xa0μm and grip force among 1, 2, and 3xa0N, we measured the time required for division and bursting pressure of coagulating dissection. An in vivo experiment in a pig was also used to confirm the usefulness of the articulating USAD in laparoscopic operations.ResultsDivision time did not differ significantly between the articulating USAD and HSII with an 80-μm amplitude of vibration and a grip force of 2 or 3xa0N. Bursting pressure of blood vessels showed no significant difference between articulating USAD and HSII under all experimental conditions. In the in vivo experiment, the new bendable tip of the articulating USAD displayed coagulating dissection performance equivalent to that of the traditional USAD.ConclusionsWe have developed a new articulating USAD that can broaden the range of methods and approaches available for USADs and improve usefulness and safety.

Dynamics of metabolic changes in intracranial metastases and distant normal-appearing brain tissue after stereotactic radiosurgery: A serial proton magnetic resonance spectroscopy study

The present study evaluated the dynamics of metabolic changes in intracranial metastases and distant normal-appearing brain after stereotactic radiosurgery (SRS). Forty neoplasms were evaluated with single-voxel proton magnetic resonance spectroscopy (1H-MRS) both before and after treatment. From one to six examinations (median, 3) were done in each individual case during follow-up. At the time of each investigation additional 1H-MRS was obtained from the normal-appearing brain distant from the radiosurgical target. Investigated metabolites included N-acetylaspartate (NAA), choline-containing compounds (Cho), creatine (Cr), and mobile lipids (Lip). Within the first month after SRS responded tumors showed a statistically significant increase in NAA/Cho ratio, and decrease of Cho content and Lip-to-normal brain Cr (nCr) ratio. By contrast, statistically significant metabolic alterations were not detected in stabilized tumors. Statistically significant volumetric and metabolic changes were not marked between three and 12 months after treatment in non-progressing lesions. Alternatively, decrease of NAA/Cho ratio, NAA content and Cr content, and increase in Lip/nCr ratio and Cho content were evident in progressive neoplasms, and subtle metabolic alterations could be revealed even before the increase in the lesion volume. Metabolic characteristics of normal-appearing brain distant from the radiosurgical target did not show statistically significant changes within the first year after treatment. In conclusion, additional use of serial 1H-MRS during follow-up after SRS for intracranial metastases permits detailed evaluation of the metabolic tumor response and may be potentially helpful for early prediction of recurrence.

A new concept of three-dimensional endoscope for endoscopic surgery.

1 Faculty of Advanced Technosurgery, Institute of Advanced Biomedical Engineering and Science, Graduate School of Medicine, Tokyo Women’s Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan 2 Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan 3 Department of Disaster and Emergency Medicine, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan 4 Department of Surgery, Saitama Medical Center, Saitama Medical School, 1981 Tsujido-machi, KamodaKawagoe-shi, Saitama 350-8550, Japan

Mid-Infrared Robotic Laser Surgery System in Neurosurgery

There is certain limitation to do the perfect extraction of the tumors by conventional manual surgery, because the area close to the boundary between tumors and normal brain tissue is usually left in order to keep away from destruction of normal area. For the purpose to treat such the boundary area, a computer controlled robotic laser surgery system has been developed. This system is characterized by the mid-infrared laser device which can perform less invasive precise surgery with low output power (<1.0W), and the computer controlled system which can realize the ablation of designated area on brain surface within 0.5mm dislocation. For the further study, aiming to apply to use in vivo, we have developed an auto-focus system for laser irradiation. From the results of our animal study, the system enables to maintain the focal point of the laser head on brain surface to realize constant ablation in the designated area.

Method for End Time Prediction of Brain Tumor Resections Using Analysis of Surgical Navigation Information and Tumor Size Characteristics

The rapid development in science and technology in recent years has led to corresponding developments in medical technology. At the same time, however, surgical treatments and procedures are complicated by a variety of techniques and applications of medical devices, which has led to an increase in the demands on surgical staff. To address this problem, surgical workflow analyses have been carried out to ensure the reliability of surgical techniques by visualizing and analyzing complex surgery processes. In previous studies, we visualized the removal progress of malignant brain tumors during MRI-guided navigation surgery and developed a technique to predict the time required for tumor removal using analysis of surgical navigation information. In this paper, we introduce a new method and the results of the end time prediction of tumor removal using both intraoperative performance measurements with surgical navigation data and the estimated mean incremental speed of progress using regression analysis of 20 brain tumor resection cases based on the relationship between tumor size (volume or surface direction) and removal time. The results show that the accuracy was significantly improved from the estimation based on regression analysis by adding the intraoperative progress analysis.

Video Information Management System for Information Guided Neurosurgery

As the boundary between glioblastoma and normal tissue is unclear, precise resection is required to reduce the risk of post-operative adverse event such as aphasia and to elongate residual life of the patient by resecting tumor region completely. Surgeons use various information such as preoperative and intraoperative image, surgical navigation, pathological images, and so on, to decide resection line. In conventional operating room, information is dispersed. In this study, video information integration system was implemented using dedicated hardware video mixer. In clinical evaluation, pre-set window layout was selected just by pushing a button, and neither delay nor noise was observed. In the future study, we will implement automatic layout changing system depending on the surgical scenario.

Development of Hitchcock stereotactic frame for intraoperative open MRI

We have introduced open MRI into the operating room. When taking intraoperative open MR (iMR) images conventionally, since it was impossible to have used a conventional head coil for diagnosis because of need of space, we used to wrap the body coil around the patient’ head to get signal. However, the body coil was less sensitive, wrapping the coil was very rough. Then we have developed Hitchcock Coil for intraoperative open MRI (iMRI). Hitchcock Coil works not only as more sensitive receiving coil than conventional one, but also as iMRI-guided Hitchcock stereotactic device (Hitchcock device), that is to say Navigation System using markers for iMRI. This time we confirmed that Hitchcock Coil were more excellent than the conventional receiving coil in respect of contrast and space resolution, and were acceptable to iMRI.