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At least 775 records · Page 43Linked to original sources

PubMed1998

Discharge correlates of hippocampal complex spike neurons in behaving rats passively displaced on a mobile robot.

This study investigated location-, movement-, and directional-selectivity of action potential discharges of hippocampal neurons in awake rats subjected to passive displacements in order to estimate vestibular contributions to this activity. Water-deprived rats were habituated to being restrained in a sling mounted on a moving robot. The extracellular activity of single complex-spike cells in area CA1 of the hippocampus was recorded with glass micropipettes in the rats during passive translations, rotations, and immobility. The robot made a standardized series of trajectories starting from each of four corners of a square enclosure surrounded by black curtains. A drop of water was delivered to the rat each time the robot arrived at one designated corner of the arena. The activities of 29 neurons were investigated in 45 recording sessions (16 of which were in total darkness) in four rats. Hippocampal neurons recorded in 31 sessions (9 sessions in the dark) had significant location-selective increases or decreases in firing rate as the rat was passively displaced or immobile within the experimental arena. In 20 sessions (6 in the dark) direction-selective discharges were found when the rat was in the corners. In six sessions, cells discharged selectively during movement initiation or termination. These data suggest that information essential for path integration is present in the hippocampus and that inertial cues could play a vital role in hippocampal spatial functions. These results resemble those of O'Mara et al. ([1994] J Neurosci 14:6511) using the same protocol in macaques, suggesting similarities in hippocampal processing and function.

Action Potentials↗

PubMed2000

Robotic motion compensation for respiratory movement during radiosurgery.

Tumors in the chest and abdomen move during respiration. The ability of conventional radiation therapy systems to compensate for respiratory motion by moving the radiation source is inherently limited. Since safety margins currently used in radiation therapy increase the radiation dose by a very large amount, an accurate tracking method for following the motion of the tumor is of the utmost clinical relevance. We investigate methods to compensate for respiratory motion using robotic radiosurgery. Thus, the therapeutic beam is moved by a robotic arm, and follows the moving target tumor. To determine the precise position of the moving target, we combine infrared tracking with synchronized X-ray imaging. Infrared emitters are used to record the motion of the patient's skin surface. A stereo X-ray imaging system provides information about the location of internal markers. During an initialization phase (prior to treatment), the correlation between the motions observed by the two sensors (X-ray imaging and infrared tracking) is computed. This model is also continuously updated during treatment to compensate for other, non-respiratory motion. Experiments and clinical trials suggest that robot-based methods can substantially reduce the safety margins currently needed in radiation therapy.

Humans↗

PubMed2006

Randomized clinical trial of standard laparoscopic versus robot-assisted laparoscopic Nissen fundoplication for gastro-oesophageal reflux disease.

BACKGROUND: Robotic systems for minimally invasive surgery may be of added value during extensive dissection and suturing in confined spaces, such as laparoscopic Nissen fundoplication (LNF). The purpose of this trial was to compare standard LNF with robot-assisted Nissen fundoplication (RNF). METHODS: Between 2003 and 2005, 50 patients with confirmed refractory gastro-oesophageal reflux disease were assigned to LNF (25) or RNF (25). Patients who had undergone previous antireflux surgery were excluded. Independent assessment of dysphagia, regurgitation, heartburn and general well-being was performed before and 6 months after surgery using questionnaires. Objective outcome was studied 6 months after surgery by oesophageal manometry, 24-h pH monitoring, barium oesophagram series and upper endoscopy. RESULTS: Operating time, blood loss, postoperative pain scores, hospital stay and complication rates did not differ significantly between the two groups. Reoperation rates were the same (one incisional hernia after LNF and one patient with repeat Nissen after RNF because of persistent dysphagia). Postoperative self-rated change in reflux symptoms and quality of life improved equally in both groups. The reduction in oesophageal acid exposure, increase in lower oesophageal sphincter tone and mucosal healing were comparable in both groups at follow-up. CONCLUSION: RNF yielded similar subjective and objective results to LNF in this study. Therefore no additive value of robotic systems for this procedure was detected up to 6 months after surgery.

Adult↗

PubMed2004

Evaluation of an image-guided, robotically positioned transcranial magnetic stimulation system.

The emergence of transcranial magnetic stimulation (TMS) as a tool for investigating the brain has been remarkable over the past decade. While many centers are now using TMS, little has been done to automate the delivery of planned TMS stimulation for research and/or clinical use. We report on an image-guided robotically positioned TMS system (irTMS) developed for this purpose. Stimulation sites are selected from functional images overlaid onto anatomical MR images, and the system calculates a treatment plan and robotically positions the TMS coil following that plan. A new theory, stating that cortical response to TMS is highest when the induced E-field is oriented parallel to cortical columns, is used by the irTMS system for planning the position and orientation of the TMS coil. This automated approach to TMS planning and delivery provides a consistent and optimized method for TMS stimulation of cortical regions of the brain. We evaluated the positional accuracy and utility of the irTMS system with a B-shaped TMS coil. Treatment plans were evaluated for sites widely distributed about a head phantom with well-defined landmarks. The overall accuracy in positioning the planned site of the TMS coil was approximately 2 mm, similar to that reported for the robot alone. The estimated maximum range of error in planned vs. delivered E-field strength was +4%, suggesting a high degree of accuracy and reproducibility in the planned use of the irTMS system.

Brain↗

PubMed2006

A robot-assisted study of intrinsic muscle regulation on proximal interphalangeal joint stiffness by varying metacarpophalangeal joint position.

The tightness of intrinsic hand muscles is a common cause of finger joint stiffness. The purposes of this study were to develop a robot-assisted methodology to obtain torque-angle data of a finger joint, and to investigate the regulation of the intrinsic muscles on finger joint stiffness. Our robot system features the integration of a low payload robot arm, a controller, and a force/torque transducer. The system provided highly reproducible torque-angle curves. Torque-angle data of the proximal interphalangeal joint with the metacarpophalangeal joint at 0 and 60 degrees were obtained from eight asymptomatic hands. The torque-angle curve shifted with the position of the metacarpophalangeal joint. As the metacarpophalangeal joint flexion angle changed from 60 to 0 degrees, the equilibrium of the proximal interphalangeal joint increased more than 20 degrees, and joint stiffness increased more than 50%. The dependence of the stiffness of the proximal interphalangeal joint on metacarpophalangeal joint position supports the regulatory role of the intrinsic muscles on finger joint mechanics. This regulatory mechanics is likely amplified in hands with intrinsic muscle tightness, justifying the commonly used Bunnell Intrinsic Tightness Test.

Adult↗

PubMed2002

Telepathology in a routine clinical environment: implementation and accuracy of diagnosis by robotic microscopy in a one-stop breast clinic.

The concept of using telepathology as a way of increasing the efficiency of pathologists is not new. There have been many studies attempting to evaluate the role of telepathology diagnosis, predominantly using transmission of still digital images. This study evaluates the potential value of remote diagnosis using robotic microscopy in the setting of a one-stop breast clinic. A Zeiss Axiopath telepathology system was used. The aim was to identify deficiencies in software and the minimum specifications for the computer hardware and network capability needed for reproducible pathological diagnosis with a view to developing a system that can preclude the need for an on-site pathologist. Forty-seven fine needle aspiration smears were diagnosed simultaneously by a pathologist in the breast clinic and by a different pathologist operating a robotic microscope situated in the clinic in a different wing of the hospital from the pathology department. The diagnoses, the time taken for clinic and remote diagnosis, and difficulties in using the system were recorded. Absolute correlation was achieved in 80.9% of cases. There was one false-positive diagnosis of cancer and no false negatives. The mean time taken for diagnosis per case was 2.39 min in clinic and 10.81 min by remote control robotic microscopy. However, as the pathologist did not have to leave the department, remote diagnosis was overall more economical of pathologists' time. Image quality was generally found to be good and not an obstacle to diagnosis. There were operational and technical problems that made remote diagnosis tedious and lengthy. Although at present the system is not capable of replacing an on-site pathologist, the results were encouraging and suggest that remote control remote diagnosis has the potential to increase the efficiency of pathologists.

Biopsy, Needle↗

PubMed2002

Robotic telepathology: efficacy and usability in pulmonary pathology.

Robotic telepathology is well established in the USA as a method of case referral, but is less frequently used in the UK. Using cases covering a broad spectrum of pulmonary pathology, this study assessed its application in primary diagnosis and its functionality in terms of accuracy of diagnosis and time per case, for both small biopsies and open lung biopsies/resections. Forty cases (20 bronchoscopic and 20 surgical lung biopsy/resection specimens) were reviewed in blinded fashion by a single pathologist using robotic telepathology. Connection between the John Radcliffe and Royal Brompton Hospitals was via 10 Mb/s LAN to the Internet (supported by the Joint Academic Network). The cases were then randomized and reviewed a second time with conventional light microscopy. Diagnosis, initial time to reach diagnosis, and overall time per case were recorded. In two bronchoscopic biopsy cases, there were clinically significant differences between telepathology and conventional light microscopy, one probably attributable to user inexperience and the other to either speed of image capture or digital image quality. In the surgical lung biopsies and resections, there was one variation of opinion: with telepathology a case was considered to be probably mesothelioma, whereas this was thought less likely on light microscopy. In both instances, immunohistochemistry was requested prior to clinical management. Telepathology was 14 times slower than conventional light microscopy when examining bronchoscopic biopsies. The average time spent per slide was 7 min 21 s, compared with 32 s per slide with conventional light microscopy. When assessing open lung biopsies and resections, telepathology was five times slower, at 6 min 13 s compared with 1 min 10 s with conventional light microscopy. This study showed that robotic telepathology is accurate for primary diagnosis in pulmonary histopathology, but modifications in both laboratory protocols and telepathology hardware are needed to decrease the time difference between telepathology and conventional light microscopy, for telepathology to be usable within the framework of a busy referral practice.

Biopsy↗

PubMed1999

A robotics-based automated assay for inorganic and organic phosphates.

Phosphate analyses are fundamental to a broad range of biochemical applications involving inorganic phosphate and organic phosphoesters such as phospholipids, phosphorylated proteins, and nucleic acids. A practical automated method utilizing robotics is described in this report. Five colorimetric methods of phosphate analyses based on formation of a phosphomolybdate complex and compatible with the automated assay were tested, and the fundamental chemistry is discussed. The relative sensitivities are malachite green > crystal violet > quinaldine red > ascorbate reduction > antimony-modified ascorbate reduction, although only a fourfold improvement was observed in going from the modified ascorbate procedure to malachite green. Malachite green was selected to optimize the assay because this dye provided the highest sensitivity. However, where color stability and low blanks are more important than sensitivity, the ascorbate reduction and quinaldine red methods were found to be better choices than malachite green. Automation using a robotic liquid-handling system substantially reduces the labor required to process large arrays of samples. The result is a sensitive, nonradioactive assay of inorganic phosphate with high throughput. A digestion step in an acid-resistant 96-well plate was developed to extend the assay to phosphate esters. The robotic-based assay was demonstrated with inorganic phosphate and a common phospholipid, phosphatidylcholine.

Automation↗

PubMed2005

DaVinci canvas: a telerobotic surgical system with integrated, robot-assisted, laparoscopic ultrasound capability.

We present daVinci Canvas: a telerobotic surgical system with integrated robot-assisted laparoscopic ultrasound capability. DaVinci Canvas consists of the integration of a rigid laparoscopic ultrasound probe with the daVinci robot, video tracking of ultrasound probe motions, endoscope and ultrasound calibration and registration, autonomous robot motions, and the display of registered 2D and 3D ultrasound images. Although we used laparoscopic liver cancer surgery as a focusing application, our broader aim was the development of a versatile system that would be useful for many procedures.

Computer Graphics↗

PubMed2005

Gaze-contingent soft tissue deformation tracking for minimally invasive robotic surgery.

The introduction of surgical robots in Minimally Invasive Surgery (MIS) has allowed enhanced manual dexterity through the use of microprocessor controlled mechanical wrists. Although fully autonomous robots are attractive, both ethical and legal barriers can prohibit their practical use in surgery. The purpose of this paper is to demonstrate that it is possible to use real-time binocular eye tracking for empowering robots with human vision by using knowledge acquired in situ. By utilizing the close relationship between the horizontal disparity and the depth perception varying with the viewing distance, it is possible to use ocular vergence for recovering 3D motion and deformation of the soft tissue during MIS procedures. Both phantom and in vivo experiments were carried out to assess the potential frequency limit of the system and its intrinsic depth recovery accuracy. The potential applications of the technique include motion stabilization and intra-operative planning in the presence of large tissue deformation.

Artificial Intelligence↗

PubMed2005

A hand-eye robotic model for total knee replacement surgery.

This paper presents a hand-eye robotic model for total knee replacement (TKR) surgery. Unlike existent robot assisted TKR surgery, the proposed model is a surgical robot that combines with a movable hand-eye navigation system, which would use the full potential of both computer-assisted systems. Without using CT images and landmark pins in the patient's bones, it can directly measure the mechanical axis with high precision. This system provides a new approach of the minimally invasive surgery. Experiment results show that the proposed model is promising in the future application.

Arthroplasty, Replacement, Knee↗

PubMed1992

Potential use of robots in endoscopic neurosurgery.

A 6-axis stereotactic robot has been designed and linked to a stereotactic frame for routine use. Robot software allows the positioning of a probe holder in order to reach a given target. A calibration step enables the robot to compute the position of the x-ray beam and correct its final position to avoid parallax errors. The co-ordinates of the target are presently taken from anteroposterior and lateral X-rays using a digitizing table. Connection with a digitized angiography system is in progress and will allow direct sampling of numerical data from the x-ray data. Further steps will include connections with a 3D-reconstructed image from MRI and CAT as well as with a resident computerized atlas. Present experience after 14 months of daily practice represents 140 stereotactic procedures which can be extended to any special use, including endoscopic approaches.

Brain Diseases↗

PubMed2004

Optimised robot-based system for the exploration of elastic joint properties.

Numerous publications provide measured biomechanical data relating to synovial joints. However, in general, they do not reflect the non-linear elastic joint properties in detail or do not consider all degrees of freedom (DOF), or the quantity of data is sparse. To perform more comprehensive, extended measurements of elastic joint properties, an optimised robot-based approach was developed. The basis was an industrial, high-precision robot that was capable of applying loads to the joint and measuring the joint displacement in 6 DOF. The system was equipped with novel, custom-made control hardware. In contrast to the commonly used sampling rates that are below 100 Hz, a rate of 4 kHz was realised for each DOF. This made it possible to implement advanced, highly dynamic, quasi-continuous closed-loop controllers. Thus oscillations of the robot were avoided, and measurements were speeded up. The stiffness of the entire system was greater than 44 kNm(-1) and 22 Nm deg(-1), and the maximum difference between two successive measurements was less than 0.5 deg. A sophisticated CT-based referencing routine facilitated the matching of kinematic data with the individual anatomy of the tested joint. The detailed detection of the elastic varus-valgus properties of a human knee joint is described, and the need for high spatial resolution is demonstrated.

Biomechanical Phenomena↗

PubMed1997

Minimally invasive 3D data registration in computer and robot assisted total knee arthroplasty.

Computer and robot assisted surgery is concerned with the improvements achievable by using computer methods and robotic devices to plan and execute surgical interventions. The registration of different coordinate frames, often achieved through the matching of 3D data sets, represents a crucial step connecting planning and execution. Orthopaedic surgery already features a number of functioning applications which include registration routines relying on presurgically implanted fiducial markers. Replacing such invasive routine with non-fiducial registration procedures is regarded as a necessary step towards a minimisation of surgical invasiveness. A minimally invasive registration technique based on the iterative closest point algorithm is presented and conceived for a specific computer and robot assisted orthopaedic reconstructive intervention, namely total knee arthroplasty. The whole surgical protocol is examined in detail and the experimental results, relative to tests performed on synthetic and animal specimens, are thoroughly reported and discussed. The authors indicate that the proposed registration approach is well-suited for the relevant application and appropriate for in vivo testing.

Algorithms↗

PubMed2000

Insect visual homing strategies in a robot with analog processing.

The visual homing abilities of insects can be explained by the snapshot hypothesis. It asserts that an animal is guided to a previously visited location by comparing the current view with a snapshot taken at that location. The average landmark vector (ALV) model is a parsimonious navigation model based on the snapshot hypothesis. According to this model, the target location is unambiguously characterized by a signature vector extracted from the snapshot image. This article provides threefold support for the ALV model by synthetic modeling. First, it was shown that a mobile robot using the ALV model returns to the target location with only small position errors. Second, the behavior of the robot resembled the behavior of bees in some experiments. And third, the ALV model was implemented on the robot in analog hardware. This adds validity to the ALV model, since analog electronic circuits share a number of information-processing principles with biological nervous systems; the analog implementation therefore provides suggestions for how visual homing abilities might be implemented in the insect's brain.

Animals↗

PubMed1997

[Robot arm in laparoscopic surgery].

Currently laparoscopic surgery is limited by several factors. One of them is the precise handling of optics. Up to now, in our hospital 52 laparoscopic operations have been done with a voice-controlled robot arm to handle the optics in gallbladder, stomach, large bowel and hernia operations. The visual field is determined by the surgeon. In all cases handling of the robot arm was precise and the voice response exact and without technical problems. Twenty-nine operations were done by one operator as "solo surgeries". In 20 further cases there was one assistant. A robot arm can be used successfully without problems by any laparoscopic surgeon in any operating theater.

Equipment Design↗

PubMed1997

[Robot-assisted knee endoprosthesis].

With the development of powerful computer systems, computer-assisted medical diagnosis and therapy have become common over the last 10 years. Even in the surgical field, computer- and robotic-assisted techniques are becoming practical but are not yet used on a daily basis. In the orthopaedic field, computer and robotic assistance is used in planning and performing demanding three-dimensional osteotomies, setting pedicle screws in the spine and milling the femoral medullary canal in total hip replacement. This article introduces a computer- and robotic-assisted system for performing arthroplasty in total knee replacement procedures.

Computer Simulation↗

PubMed2000

[CRIGOS: development of a compact robot for image-guided orthopedic surgery].

In this paper, we present a medical robot system dedicated to support the surgeon during challenging tasks within orthopedic interventions. The main goal of this work is to develop a system as technically simple as the surgical requirements allow to keep its cost and complexity to a minimum. Therefore, we primarily focus on calibrated X-ray imaging for image acquisition, an easy registration procedure and robotic execution using a positioning device with simple parallel kinematics. Examples of different orthopedic interventions using the compact robot system for image-guided orthopedic surgery (CRIGOS) are presented, as well as various modes of execution of the device.

Arthroplasty, Replacement, Knee↗