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Hiroshi Iseki

Publications and source records attributed to Hiroshi Iseki.

17 recordsLinked to original sources
PubMed2007

[Information guided technology and procedure in neurosurgical field].

Translational Research is the research to apply and mediate a fundamental research result to the clinical field effectively. The integration of the diagnosis and the treatment is an important item in the life science field from the viewpoint of quality of therapy and minimally invasive therapy. The standardization of mechanical interface of the medicine related machine, system and a medical information system are important from the viewpoint such as prevention of medical malpractice. A high function operating robot (manipulator) as an endoscopic robot and image-guided minimally invasive device are important in the point of view of the development of a medical device shown with a medical device industry vision. We describe an outline of our ongoing development of endoscope system, intraoperative MRI (intelligent operating theater) and robot surgery system in neurosurgical field.

Humans↗
PubMed2006

New radiofrequency coil integrated with a stereotactic frame for intraoperative MRI-controlled stereotactically guided brain surgery.

Mislocalization errors caused by MR image distortions or brain shift are one of the main causes of complications after stereotactically guided neurosurgical procedures. A special device, which could ameliorate such effects and provide intraoperative acquisition of MR images of sufficient diagnostic accuracy, was developed. It is composed of a radiofrequency receiver coil integrated with a modified Komai stereotactic frame and a Sugita four-pin head holder. Clinical testing revealed that the use of the device during stereotactically guided procedures under the control of low magnetic field strength (0.3 T) intraoperative MRI ameliorates the effects of brain shift, and permits to obtain informative tissue samples and to perform aggressive removal of the lesion without any damage of the eloquent cerebral structures. The possibility of an easy shift from a stereotactically guided to a routine microneurosurgical procedure represents an additional benefit of the developed device.

Adolescent↗
PubMed2006

Three-way bipolar forceps: a novel bipolar coagulator system for nerve stimulation and detection of nerve potentials.

Preoperative characterization of brain anatomy by magnetic resonance imaging and intraoperative functional characterization of the nervous system is essential in patients undergoing radical resection of brain tumors. A novel integrated system was developed combining conventional bipolar forceps with an electric stimulator and an oscilloscope. The system consists of a mechanical switching circuit allowing a wide range of electric characteristics and was designed to perform intraoperative electrophysiological studies, including functional mapping and measurements of motor evoked potentials (MEPs) and somatosensory evoked potentials (SEPs). This system achieved a significant reduction in exchange time (from 3.63+/-1.00 sec to 1.12+/-0.42 sec) between coagulation and stimulation, and reproducible measurement of MEPs from porcine limbs by cortical stimulation using the bipolar forceps. Functional mapping under awake craniotomy was carried out by cortical stimulation in patients with glioblastoma, and median nerve SEPs with high signal-to-noise ratio were elicited from the bipolar forceps on the sensory cortex of patients under general anesthesia. This integrated system is technically easy to operate and allows functional monitoring of an area that would otherwise be difficult to access using conventional methods. This three-way bipolar forceps system may reduce postoperative complications in patients undergoing neurosurgical procedures.

Adult↗
PubMed2005

Intraoperative tumor segmentation and volume measurement in MRI-guided glioma surgery for tumor resection rate control.

RATIONALE AND OBJECTIVES: Gross-total surgery under intraoperative magnetic resonance imaging (MRI) is a promising method of glioma removal. The purpose of this article is intraoperative measurement of resected tumor volume in MRI-guided glioma surgery using semiautomatic image segmentation to unbiased resection rate control. MATERIALS AND METHODS: A newly developed software program based on a fuzzy connectedness (FC) segmentation algorithm was used to achieve fast and semiautomatic tumor segmentation and tumor volume measurement. The program was validated by retrospective study of eight glioma cases and then applied to seven glioma cases. All clinical cases underwent actual MRI-guided surgery using 0.3-T open magnets. RESULTS: The volume of the tumor before resection ranged from 10.1 to 206.7 mL. A comparison of the results of manual segmentation with those of the semiautomatic FC-based segmentation gave an average dice similarity coefficient of 0.80 and an average match of 76%. Volume measurement combined with a developed software program enabled quantitative monitoring of tumor removal, which was critical in the near-total resection of glioma in MRI-guided surgery. CONCLUSION: The FC-based tumor segmentation method can be used for intraoperative tumor segmentation and volume measurement in MRI-guided glioma surgery using 0.3-T open magnets. This method is useful for objective resection rate monitoring, which may ultimately minimize the amount of residual tumor in glioma surgery.

Adolescent↗
PubMed2005

Intelligent operating theater using intraoperative open-MRI.

Malignant brain tumors vary among patients and are characterized by their irregular shapes and infiltration. Localization of functional areas in the brain also differs among patients, and excess removal of tumor near eloquent areas may increase the risk of damage of function, such as motor paresis and speech disturbance. Recent progress in magnetic resonance (MR) imaging technology has enabled acquisition of intraoperative images and totally changed the neurosurgery of malignant brain tumors. Before, surgeons could merely speculate about the results of surgical manipulation and have no certainty about procedure outcomes until postoperative examination. Because intraoperative MR images allow visualization of the size of residual tumor(s) and the positional relationship between the tumor(s) and eloquent areas, surgeons are now able to achieve safe and reliable surgery. As an example, positional error on preoperative MR images caused by shifting of the brain (brain shift), a long-standing annoyance for surgeons, has been resolved using intraoperative MR images for surgical navigation, allowing precise resection. Two types of open-MR imaging scanner, a 0.2- or 0.3-tesla hamburger-type scanner with a horizontal gap and a 0.12- or 0.5-tesla double doughnut-type scanner with a vertical gap, are now available in the operating theater, and 1.5-tesla bore-type scanners are available. A 3.0-tesla bore-type scanner is planned. Intraoperative MR imaging includes diffusion-tensor and diffusion-weighted imaging, which allows visualization of nerve fibers in the white matter, especially the pyramidal tract. Such images are valuable aids in the precise resection of residual lesions of malignant brain tumors near eloquent areas without injuring motor function.

Brain Neoplasms↗
PubMed2005

Image-guided neurosurgery system integrating AR-based navigation and open-MRI monitoring.

As endoscopic surgery has become a popular form of minimally invasive surgery, it increasingly requires useful imaging tools to help the surgeons perform safe and secure operations. Our navigation system provides surgeons with visual information by overlaying 3D wire frame models of tumor onto live images, as well as by displaying relative the positions of surgical tools and the target tumor. Such 3D wire frame models are generated from pre-operative CT/MR images with the help of a 3D surgical simulation software. Another important function of our system is real-time volume rendering of intra-operative MR images for the target tumor. This function allows surgeons to carefully observe the vicinity of the tumor regions to be removed, by rendering the sectional views with respect to the surgical tool position, so that surgical performance can be easily monitored during the operation. We tested this navigation system in more than 10 clinical operations and verified the effectiveness of the navigation and surgical performance.

Brain Diseases↗
PubMed2004

Preoperative mapping for patients with supplementary motor area epilepsy: multimodality brain mapping.

Surgical management and strategies for the supplementary motor area (SMA) epilepsy are described. The following is our preoperative evaluations. The steps include functional magnetic resonance imaging (fMRI), interictal dipole tracing (DT), subdural electrodes mapping, measurements of movement-related cortical potential (MRCP), and the use of the intraoperative open MRI under conscious craniotomy. Six patients with SMA epilepsy underwent surgery after the mapping procedures and are now seizure-free. Combinations of preoperative (fMRI, subdural electrodes mapping) and intraoperative mapping allow exact localization and identification of the critical functional areas. Early postoperative deficits in motor and speech function were profound but patients recovered rapidly. It is concluded that the step of mapping procedures plays an important role in the management of SMA epilepsy surgery.

Adolescent↗
PubMed2004

[Preface: intuitive visualization of medical information].

Information technology(IT), visualization, and manipulation will be the key words for next generation surgery. In other words, it is awaited to make good use of intuitive visualization of medical information management by extensive use of IT in which medical science and engineering are merged and incorporated and of the process management or the visualization of treatment course using three-dimensional intraoperative images and simulation data base. In order to put it into practice, it is inevitable to establish a treatment strategy system that certainly enables surgeons to provide constantly high quality medicine. This means that to achieve the goal while optimizing the strategy toward the goal(a road map) by monitoring real-timely the pre- and intraoperative surgical planning and the operating condition of surgical devices under the control of the surgical strategy system.

Decision Making, Computer-Assisted↗
PubMed2004

[Intraoperative MRI and updated navigation].

Although advanced preoperative imaging has been developed recent years, intraoperative imaging and monitoring are limited. We have developed an operating system to obtain objective and visible information for advanced neurosurgery. Intraoperative MRI and updated navigation are powerful tools to navigate surgeons to the residual lesions. This system has contributed to the improvement of the resection rate and the safety in the cases of gliomas and pituitary tumors.

Adult↗
PubMed2004

[Robotic surgery in neurosurgical field].

Computer-aided surgery commenced in the late 1980s when computer was clinically used for diagnosis and surgical planning. Since then the computer has been used in a surgical navigation system. In the early 1990s a robotic surgery using intelligent manipulator as surgeon's new hands took place. Nowadays intraoperative diagnostic imaging as surgeon's new eyes has become ubiquitous Diagnosis, surgical planning, and navigation are required to be real-timely performed intraoperatively. The time has really come to concurrently diagnose and treat, in which technology visualizing intraoperative medical information and minimally invasive surgery are fused. For that it is necessary to develop a system that real-timely updates information for decision making, and at the same time to present the timely, optimum treatment to be done according to the results of instant evaluation of ongoing treatment. To realize and support above system it is essential to combine a sensor which can precisely distinguishes a focal area from a normal tissue intraoperatively, and a manipulator which participates the treatment. In addition, the manipulator should be accurately controlled using a computer (computer-aided manipulation) according to the surgical plan made by a method aided by a computer (computer-aided design) based on intraoperatively acquired information. It is about to change quality of life to quality of treatment.

Humans↗
PubMed2002

Endoscopic augmented reality navigation system for endonasal transsphenoidal surgery to treat pituitary tumors: technical note.

OBJECTIVE: Endoscopes have been commonly used in transsphenoidal surgery to treat pituitary tumors, to compensate for the narrow surgical field. Although many navigation systems have been introduced for neurosurgical procedures, there have been few reports of navigation systems for endoscopic operations. This report presents our recently developed, endoscopic, augmented reality (AR) navigation system. METHODS: The technology is based on the principles of AR environment technology. The system consisted of a rigid endoscope with light-emitting diodes, an optical tracking system, and a controller. The operation of the optical tracking system was based on two sets of infrared light-emitting diodes, which measured the position and orientation of the endoscope relative to the patient's head. We used the system during endonasal transsphenoidal operations to treat pituitary tumors in 12 recent cases. RESULTS: Anatomic, "real," three-dimensional, virtual images of the tumor and nearby anatomic structures (including the internal carotid arteries, sphenoid sinuses, and optic nerves) were superimposed on real- time endoscopic live images. The system also indicated the positions and directions of the endoscope and the endoscopic beam in three-dimensional magnetic resonance imaging or computed tomographic planes. Furthermore, the colors of the wire-frame images of the tumor changed according to the distance between the tip of the endoscope and the tumor. These features were superior to those of conventional navigation systems, which are available only for operating microscopes. CONCLUSION: The endoscopic AR navigation system allows surgeons to perform accurate, safe, endoscope-assisted operations to treat pituitary tumors; it is particularly useful for reoperations, in which midline landmarks may be absent. We consider the AR navigation system to be a promising tool for safe, minimally invasive, endonasal, transsphenoidal surgery to treat pituitary tumors.

Endoscopy↗
PubMed2002

NeuRobot: telecontrolled micromanipulator system for minimally invasive microneurosurgery-preliminary results.

OBJECTIVE: Microneurosurgery can be performed less invasively with the recent advances in neuronavigation and neuroendoscopy. For even less invasive microneurosurgery, we have developed a telecontrolled micromanipulator system. METHODS: The NeuRobot telecontrolled micromanipulator system was developed. With the use of this system, surgical simulations were performed with a human cadaveric head. RESULTS: The system consists of four main parts, i.e., a micromanipulator (slave manipulator), a manipulator-supporting device, an operation-input device (master manipulator), and a three-dimensional display monitor. Three 1-mm forceps and a three-dimensional endoscope, which could be remotely controlled with three degrees of freedom (rotation, neck swinging, and forward/backward motion), were installed in the slave manipulator. All surgical procedures were accurately performed with this system. CONCLUSION: The use of telecontrolled manipulator systems in neurosurgery is very promising, and we are convinced that this system will facilitate more accurate, less invasive microneurosurgery. The details of the NeuRobot system and preliminary results are presented.

Cadaver↗
PubMed2002

Minimally invasive endoscope-assisted endonasal trans-sphenoidal microsurgery for pituitary tumors: experience with 215 cases comparing with sublabial trans-sphenoidal approach.

Recent advances in endoscopic surgery have developed an endonasal route suitable for pituitary surgery. The main goal of this article is to evaluate benefits of our endoscope-assisted endonasal trans-sphenoidal microsurgery for pituitary tumors in 215 consecutive cases. The pathological classifications of the 215 cases are as follows: 163 pituitary adenomas, 23 Rathke's cleft cysts, 17 craniopharyngiomas, and 12 others. The patients were surgically treated via the endonasal trans-sphenoidal approach using an operating microscope as the primary instrument for tumor resection. Endoscopes were used to complement the operating microscope in visualization. We compared the new approach to the sublabial trans-sphenoidal approach (197 cases) with respect to endocrinological outcomes and surgical complications. Our endonasal trans-sphenoidal approach was beneficial in eliminating the complications of lip numbness, which was often observed in patients undergoing sublabial surgery, and nasal septal perforation. In addition, endocrinological outcome comparable to those in the sublabial group was achieved in the endonasal group. We consider that the endoscope, which allows visualization of areas not seen with the operating microscope, should be used actively in conjunction with the operating microscope that provides three-dimensional visualization and is timesaving. Our surgical method for pituitary tumors provides good results with minimal invasion, by exploiting the advantages of a microscope and an endoscope.

Adolescent↗