A robotic assistant for stereotactic neurosurgery on small animals

Ramrath, L.; Hofmann, Ulrich G.; Schweikard, Achim

doi:10.1002/rcs.218

Cited by 15 publications

(8 citation statements)

References 16 publications

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“…Our polyimide test probe featured on its rounded tip a ring-shaped reference electrode with an appropriate hole in the PI carrier. The insertion shuttles were fixed into a parallel gripper of a high-precision stereotaxic robot's (SASSU) z-axis [3]. Position measurements were performed by high resolution video microscopy perpendicular to the probes' axis of penetration.…”

Section: Methodsmentioning

confidence: 99%

Posterausstellung P41-P60

2011

Biomedizinische Technik/Biomedical Engineering

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P44 High throughput stent coating in a fluidized bed apparatus P60 Brain mapping using μECoG signals in the 250-400 Hz band IntroductionPhacoemulsification is an important ophthalmologic procedure during cataract surgery -the most frequent surgery in humans. Here, the cataractous cortex and nucleus are removed and replaced by an artificial lens. The lens is emulsified with an ultrasonic handpiece. The tissue is then aspirated from the eye, while aspirated fluids are replaced with irrigation of isotonic saline solution. Excess ultrasonic power can damage the sensitive cornea and the capsular bag, thus high effectiveness of the emulsification is desirable. To assess individual parameters effecting the emulsification, usually trials with porcine lenses are carried out, suffering from the biological variability of the test material. Aim of our work thus was to design an evaluation system comprising a test stand and a replacement material for biological lenses. MethodsTo design the dedicated test stand conventional measuring machines were assessed.To determine the properties of hard lenses, healthy porcine lenses (n=8) were immersed for 160 min in a solution of ethanol, formalin, and 2-propanol in the ratio 4:3:3 at 36°C. After that the lenses' mechanical impedance was tested using a dynamic compression test up to 10 kHz. After curve fitting using an appropriate extended Kelvin model the Shore A -hardness was determined. The density of the lenses was measured by an immersion bath. Based on this data synthetic materials were searched. To assess the evaluation system, emulsification trials with two replacement materials (Ø 9 mm x 6 mm) and a new set of processed porcine lenses were carried out (n=8 each). Here, the time needed to drive the needle 4 mm deep into the material under a constant force of 2 N and 50% ultrasonic power was measured. ResultsFor the test stand a C-arm-design was chosen. It consists of a rigid base, a vertical linear axis actuated by a forcecontrolled BLDC motor, a tempered retaining fixture to keep the lens in place, and an integrated force sensor to measure the penetrating force. Using LabView software, force and speed of the emulsification probe vertically penetrating the lens can be controlled. The measurements with the processed porcine lenses showed a Shore A -hardness of 78±0.85 and a density of 1.02±0.13 g/cm³. A polysiloxane (Elastosil by Wacker AG, Munich, 78 Shore A , ρ=1.2 g/cm³) and a polyurethane (PMC870 by Smooth-On, Easton, PA, USA, 80 Shore A , ρ=1.02 g/cm³) were chosen. The final testing showed that not all specimens could be evaluated due to various reasons. Porcine lenses (n=5) needed 6.66±0.72 s while the polysiloxane (n=4) needed 16.5±4.9 s and the polyurethane (n=6) needed 35.5±15.0 s. ConclusionWe were able to set up a working evaluation system to assess the time needed to emulsify processed porcine lenses and two synthetic replacement materials. The mechanical set-up is able to provide a constant driving force. However, first statistical tests showed that the synthetic mat...

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Section: Methodsmentioning

confidence: 99%

Posterausstellung P41-P60

2011

Biomedizinische Technik/Biomedical Engineering

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“…Improving the robot calibration to reduce robot-positioning error would improve the overall registration since the calibration of the robot directly affects its overall positioning accuracy. 6 For example, Ramrath et al 15 employed a goniometer design to produce a remote center of motion for their small animal robot, which requires less calibration than the four-bar linkage mechanism used in this design. They achieved a positioning accuracy in free space of 32 m, which would have significantly reduced the image-tophysical-space registration error.…”

Section: Iva Micro-ct To Robot Coordinate Registrationmentioning

confidence: 99%

“…7,8,11 Robotically assisted techniques are often employed during clinical neurosurgery, 12,13 but robotic devices designed specifically for small animal interventions are a recent development. 6,[14][15][16][17] Interventional devices for small animals are primarily designed to be operated semiautonomously within a laboratory setting by animal-handling technicians and therefore are not designed to be scaled down versions of clinical robotic systems, which are used primarily to augment the skills of a trained surgeon. An interventional device for laboratory use should be designed for frequent reattachment to existing preclinical imaging systems with minimal setup and calibration, unlike clinical robotic systems, which are typically permanent installations.…”

Section: Introductionmentioning

confidence: 99%

Integration and evaluation of a needle-positioning robot with volumetric microcomputed tomography image guidance for small animal stereotactic interventions

et al. 2010

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“…The need and benefits of image-based pre-operative surgery planning in small animals has been previously reported in several studies2526272829. However, several challenges still remain with respect to using imaging for prospective planning and/or retrospective assessment of stereotactic neurosurgery in animal models.…”

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confidence: 99%

“…For instance, access to methods and instrumentation (e.g. robotic guidance described in refs 28,29) for transferring the image-based planning to the animal is limited. Non-invasive visualization of the electrode using post-operative imaging has been previously reported (e.g 30…”

mentioning

confidence: 99%

Image-based in vivo assessment of targeting accuracy of stereotactic brain surgery in experimental rodent models

Rangarajan

Velde

Gent

et al. 2016

Sci Rep

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Stereotactic neurosurgery is used in pre-clinical research of neurological and psychiatric disorders in experimental rat and mouse models to engraft a needle or electrode at a pre-defined location in the brain. However, inaccurate targeting may confound the results of such experiments. In contrast to the clinical practice, inaccurate targeting in rodents remains usually unnoticed until assessed by ex vivo end-point histology. We here propose a workflow for in vivo assessment of stereotactic targeting accuracy in small animal studies based on multi-modal post-operative imaging. The surgical trajectory in each individual animal is reconstructed in 3D from the physical implant imaged in post-operative CT and/or its trace as visible in post-operative MRI. By co-registering post-operative images of individual animals to a common stereotaxic template, targeting accuracy is quantified. Two commonly used neuromodulation regions were used as targets. Target localization errors showed not only variability, but also inaccuracy in targeting. Only about 30% of electrodes were within the subnucleus structure that was targeted and a-specific adverse effects were also noted. Shifting from invasive/subjective 2D histology towards objective in vivo 3D imaging-based assessment of targeting accuracy may benefit a more effective use of the experimental data by excluding off-target cases early in the study.Stereotactic neurosurgery is used to introduce a needle or an electrode at a precise location in the brain, for instance to perform deep brain stimulation (DBS), lesioning (e.g. ablation) or cell-based therapy in patients to ameliorate symptoms of neurological disease. Clinical use of stereotactic neurosurgery benefits from experimental research on rodent models, for instance to identify potential target regions. Likewise, small animal investigations like DBS for neuromodulation 1,2 , electrochemical/ electrolytic lesioning for creating animal models or ameliorating symptoms 3,4 , as well as gene therapy investigations involving injection of stem cells/therapeutic agents/tracers 5-7 requires stereotactic brain surgery. They rely on standard stereotaxic brain atlases (e.g. The rat brain in stereotaxic coordinates (George Paxinos and Charles Watson, Academic Press, 2006 8 ) and skull landmarks (e.g. bregma (B), lambda (L)) for localizing the target in the rodent brain and for surgery planning 9 . Stereotaxic frames used in small animal brain surgery have species-specific head mounting platforms, with a manipulator that can move in three dimensions along the axes with respect to the head holder. The targeting accuracy of such devices is dependent on numerous factors, such as inter-animal anatomical variability, positioning errors (e.g. skull flat position), scaling errors (e.g. when using the same atlas with animals of a different size or strain), errors in intra-operative localization of bregma, operator-specific deviations etc. Some of these sources of inaccuracy in small animal stereotactic surgery have been characterized in previo...

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A robotic assistant for stereotactic neurosurgery on small animals

Abstract: The system meets the requirements of targeting small functional areas within the brain of small animals and thus offers a new tool for small animal brain research.

Cited by 15 publications

References 16 publications

Posterausstellung P41-P60

Posterausstellung P41-P60

Integration and evaluation of a needle-positioning robot with volumetric microcomputed tomography image guidance for small animal stereotactic interventions

Image-based in vivo assessment of targeting accuracy of stereotactic brain surgery in experimental rodent models

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