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1.
Annu Rev Biomed Eng ; 20: 1-20, 2018 06 04.
Artigo em Inglês | MEDLINE | ID: mdl-29865874

RESUMO

As minimally invasive surgical techniques progress, the demand for efficient, reliable methods for vascular ligation and tissue closure becomes pronounced. The surgical advantages of energy-based vessel sealing exceed those of traditional, compression-based ligatures in procedures sensitive to duration, foreign bodies, and recovery time alike. Although the use of energy-based devices to seal or transect vasculature and connective tissue bundles is widespread, the breadth of heating strategies and energy dosimetry used across devices underscores an uncertainty as to the molecular nature of the sealing mechanism and induced tissue effect. Furthermore, energy-based techniques exhibit promise for the closure and functional repair of soft and connective tissues in the nervous, enteral, and dermal tissue domains. A constitutive theory of molecular bonding forces that arise in response to supraphysiological temperatures is required in order to optimize and progress the use of energy-based tissue fusion. While rapid tissue bonding has been suggested to arise from dehydration, dipole interactions, molecular cross-links, or the coagulation of cellular proteins, long-term functional tissue repair across fusion boundaries requires that the reaction to thermal damage be tailored to catalyze the onset of biological healing and remodeling. In this review, we compile and contrast findings from published thermal fusion research in an effort to encourage a molecular approach to characterization of the prevalent and promising energy-based tissue bond.


Assuntos
Procedimentos Cirúrgicos Minimamente Invasivos/instrumentação , Procedimentos Cirúrgicos Operatórios , Técnicas de Sutura , Adesivos , Colágeno/química , Cirurgia Colorretal/instrumentação , Córnea/cirurgia , Reagentes de Ligações Cruzadas , Temperatura Alta , Humanos , Lasers , Procedimentos Cirúrgicos Minimamente Invasivos/métodos , Neurônios/metabolismo , Oscilometria , Fotoquímica , Ondas de Rádio , Suturas , Tendões/cirurgia , Engenharia Tecidual , Ultrassom , Água
2.
Langmuir ; 35(33): 10725-10733, 2019 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-31291542

RESUMO

Understanding the contact and friction between soft materials is vital to a wide variety of engineering applications including soft sealants and medical devices such as catheters and stents. Although the mechanisms of friction between stiff materials have been extensively studied, the mechanisms of friction between soft materials are much less understood. Time-dependent material responses, large deformations, and fluid layers at the contact interface, common in soft materials, pose new challenges toward understanding the friction between soft materials. This article aims to characterize the three-dimensional (3D) contact interfaces in soft materials under large deformations and complex contact conditions. Specifically, we introduce a microindentation and visualization (MIV) system capable of investigating soft material contact interfaces with combined normal and shear loading. When combined with a laser scanning confocal microscope, the MIV system enables the acquisition of 3D image stacks of the deformed substrate and the indenter under fixed normal and shear displacements. The 3D imaging data allows us to quantify the 3D contact profiles and correlate them with the applied normal and shear displacements. Using a spherical indenter and a hydrogel substrate as a model system, we demonstrate that the MIV system and the associated analysis techniques accurately measure the contact area under combined normal and shear loading. Although the limited speed of confocal scanning implies that this method is most suitable for quasi-static loading conditions, potential methods to increase the imaging speed and the corresponding trade-off in image resolution are discussed. The method presented here will be useful for the future investigation of soft material contact and friction involving complex surface geometries.

3.
Langmuir ; 33(4): 854-864, 2017 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-28052675

RESUMO

The work of adhesion and work of separation are characteristic properties of a contact interface that describe the amount of energy per unit area required to adhere or separate two contacting substrates, respectively. In this work, the authors present experimental and data analysis procedures that allow the contact interface between a soft synthetic tissue and a smooth or micropatterned poly(dimethylsiloxane) (PDMS) substrate to be characterized in terms of these characteristic parameters. Because of physical geometry limitations, the experimental contact geometry chosen for this study differs from conventional test geometries. Therefore, the authors used finite element modeling to develop correction factors specific to the experimental contact geometry used in this work. A work of adhesion was directly extracted from experimental data while the work of separation was estimated on the basis of experimental results. These values are compared to other theoretical calculations for validation. The results of this work indicate that the micropatterned PDMS substrate significantly decreases both the work of adhesion and work of separation as compared to a smooth PDMS substrate when in contact with a soft synthetic tissue substrate.

4.
Eur Spine J ; 25(6): 1764-74, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-26394858

RESUMO

PURPOSE: Description of a novel method for evaluation of pedicle screws in 3 dimensions utilizing O-arm(®) and StealthStation(®) navigation; identifying sources of error, and pearls for more precise screw placement. METHODS: O-arm and StealthStation navigation were utilized to place pedicle screws. Initial and final O-arm scans were performed, and the projected pedicle probe track, projected pedicle screw track, and final screw position were saved for evaluation. They were compared to evaluate the precision of the system as well as overall accuracy of final screw placement. RESULTS: Thoracolumbar deformity patients were analyzed, with 153 of 158 screws in adequate position. Only 5 screws were malpositioned, requiring replacement or removal. All 5 were breached laterally and no neurologic or other complications were noted in any of these patients. This resulted in 97 % accuracy using the navigation system, and no neurological injuries or deficits. The average distance of the screw tip and angle of separation for the predicted path versus the final pedicle screw position were analyzed for precision. The mean screw tip distance from the projected tip was 6.43 mm, with a standard deviation of 3.49 mm when utilizing a navigated probe alone and 5.92 mm with a standard deviation of 3.50 mm using a navigated probe and navigated screwdriver (p = 0.23). Mean angle differences were 4.02° and 3.09° respectively (p < 0.01), with standard deviations of 2.63° and 2.12°. CONCLUSIONS: This new technique evaluating precision of screw placement in 3 dimensions improves the ability to define screw placement. Pedicle screw position at final imaging showed the use of StealthStation navigation to be accurate and safe. As this is a preliminary evaluation, we have identified several factors affecting the precision of pedicle screw final position relative to that predicted with navigation.


Assuntos
Imageamento Tridimensional , Procedimentos Ortopédicos , Parafusos Pediculares , Cirurgia Assistida por Computador , Humanos , Imageamento Tridimensional/efeitos adversos , Imageamento Tridimensional/métodos , Imageamento Tridimensional/estatística & dados numéricos , Procedimentos Ortopédicos/efeitos adversos , Procedimentos Ortopédicos/métodos , Procedimentos Ortopédicos/estatística & dados numéricos , Cirurgia Assistida por Computador/efeitos adversos , Cirurgia Assistida por Computador/métodos , Cirurgia Assistida por Computador/estatística & dados numéricos
5.
Surg Endosc ; 29(7): 1999-2005, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25318365

RESUMO

INTRODUCTION: Harvested biological tissue is a common medium for surgical device assessment in a laboratory setting; this study aims to differentiate between surgical device performance in the clinical and laboratory environments prior to and following tissue storage. Vascular tissue fusion devices are sensitive to tissue-device temperature gradients, tissue pre-stretch in vivo and tissue water content, each of which can vary during tissue storage. In this study, we compare the results of tissue fusion prior to and following storage using a standardized bursting pressure protocol. METHODS: Epigastric veins from seven porcine models were subject to identical bursting pressure protocols after fusion. One half of each vein was fused in vivo, harvested and immediately analyzed for burst pressure; the remainder was stored (0.9% Phosphate Buffered Saline, 24h, 4 °C) and then analyzed ex vivo. Histological slides were prepared for qualitative analysis of in versus ex vivo fusions. RESULTS: Bursting pressures of vessels fused ex vivo (514.7 ± 187.0 mmHg) were significantly greater than those of vessels fused in vivo (310 ± 127.7 mmHg, p = 2.06 E-10). Histological imaging of venous axial cross-sections indicated the lamination of adventitia and media layers ex vivo, whereas in vivo samples consisted only of adventitia. CONCLUSION: These findings suggest that the fusion of porcine venous tissue ex vivo may overestimate the clinical performance of fusion devices. Prior work has indicated that increased tissue hydration and the lamination of tissue layers both positively affect arterial fusion bursting pressures. The bursting pressure increase observed herein may therefore be due to storage-induced alterations in tissue composition and mechanics of the fusion interface. While harvested tissue provides an accessible medium for comparative study, the fusion of vascular tissue in vivo may avoid storage-induced biomechanical alterations and is likely a better indicator of fusion device performance in a clinical setting.


Assuntos
Fenômenos Biomecânicos , Modelos Anatômicos , Pressão , Preservação de Tecido , Veias , Animais , Desenho de Equipamento , Técnicas In Vitro , Ligadura/instrumentação , Equipamentos Cirúrgicos , Suínos
6.
J Biomech Eng ; 137(12): 121010, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26513403

RESUMO

Surgical tissue fusion devices ligate blood vessels using thermal energy and coaptation pressure, while the molecular mechanisms underlying tissue fusion remain unclear. This study characterizes the influence of apposition force during fusion on bond strength, tissue temperature, and seal morphology. Porcine splenic arteries were thermally fused at varying apposition forces (10-500 N). Maximum bond strengths were attained at 40 N of apposition force. Bonds formed between 10 and 50 N contained laminated medial layers; those formed above 50 N contained only adventitia. These findings suggest that commercial fusion devices operate at greater than optimal apposition forces, and that constituents of the tunica media may alter the adhesive mechanics of the fusion mechanism.


Assuntos
Ablação por Cateter/métodos , Técnicas Hemostáticas , Artéria Esplênica/fisiopatologia , Artéria Esplênica/cirurgia , Resistência à Tração/fisiologia , Procedimentos Cirúrgicos Vasculares , Adesividade , Animais , Artérias , Técnicas In Vitro , Pressão , Estresse Mecânico , Suínos
7.
IEEE Trans Biomed Eng ; 71(4): 1151-1160, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37910420

RESUMO

OBJECTIVE: To enhance visualization in pediatric Otolaryngology middle ear surgeries and reduce mastoidectomy instances, we introduce a novel Articulating Chip-on-Tip Endoscope (ACoT Endo). METHODS: The ACoT Endo incorporates a cable-driven distal end camera and off-the-shelf Chip-on-Tip camera to improve visualization. We compared its capabilities with standard endoscopes, evaluating its bending capacity (70 ° ± 2 °) and center axis rotation (360 °). To test the overall functionality of this device, a Mock Ear was created to simulate the anatomy of the human ear, and the ACoT Endo's ability to be used in this cavity is compared to a standard 0 ° Karl Storz endoscope through tests with the Mock Ear and respective endoscopes. RESULTS: The ACoT Endo accurately captured surgical details similar to standard endoscopes in the ENT field. Compared to the 0 ° Karl Storz endoscope, the ACoT Endo demonstrated an increased field of view by approximately 69% and captured area by approximately 249%. ACot Endo allowed the surgeon to effortlessly articulate the camera with the rotation of a finger, while an excision tool was inserted in the middle ear, a procedure that is currently extremely difficult with standard endoscopes. CONCLUSION: The ACoT Endo's dynamic viewing angle and Chip-on-Tip camera enable unparalleled surgical visualization within the middle ear using a single endoscope, offering potential benefits in Otolaryngology procedures. SIGNIFICANCE: By reducing the need for invasive mastoidectomies and providing better visualization tools, the ACoT Endo has significant potential to improve outcomes and safety in pediatric middle ear surgeries.


Assuntos
Orelha Média , Endoscópios , Humanos , Criança , Orelha Média/cirurgia , Endoscopia
8.
IEEE J Biomed Health Inform ; 27(7): 3302-3313, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37067963

RESUMO

In recent years, several deep learning models have been proposed to accurately quantify and diagnose cardiac pathologies. These automated tools heavily rely on the accurate segmentation of cardiac structures in MRI images. However, segmentation of the right ventricle is challenging due to its highly complex shape and ill-defined borders. Hence, there is a need for new methods to handle such structure's geometrical and textural complexities, notably in the presence of pathologies such as Dilated Right Ventricle, Tricuspid Regurgitation, Arrhythmogenesis, Tetralogy of Fallot, and Inter-atrial Communication. The last MICCAI challenge on right ventricle segmentation was held in 2012 and included only 48 cases from a single clinical center. As part of the 12th Workshop on Statistical Atlases and Computational Models of the Heart (STACOM 2021), the M&Ms-2 challenge was organized to promote the interest of the research community around right ventricle segmentation in multi-disease, multi-view, and multi-center cardiac MRI. Three hundred sixty CMR cases, including short-axis and long-axis 4-chamber views, were collected from three Spanish hospitals using nine different scanners from three different vendors, and included a diverse set of right and left ventricle pathologies. The solutions provided by the participants show that nnU-Net achieved the best results overall. However, multi-view approaches were able to capture additional information, highlighting the need to integrate multiple cardiac diseases, views, scanners, and acquisition protocols to produce reliable automatic cardiac segmentation algorithms.


Assuntos
Aprendizado Profundo , Ventrículos do Coração , Humanos , Ventrículos do Coração/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Algoritmos , Átrios do Coração
9.
Surg Endosc ; 26(10): 2862-9, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22538681

RESUMO

BACKGROUND: The state-of-the-art technology for gastrointestinal (GI) tract exploration is a capsule endoscope (CE). Capsule endoscopes are pill-sized devices that provide visual feedback of the GI tract as they move passively through the patient. These passive devices could benefit from a mobility system enabling maneuverability and controllability. Potential benefits of a tethered robotic capsule endoscope (tRCE) include faster travel speeds, reaction force generation for biopsy, and decreased capsule retention. METHODS: In this work, a tethered CE is developed with an active locomotion system for mobility within a collapsed lumen. Micro-patterned polydimethylsiloxane (PDMS) treads are implemented onto a custom capsule housing as a mobility method. The tRCE housing contains a direct current (DC) motor and gear train to drive the treads, a video camera for visual feedback, and two light sources (infrared and visible) for illumination. RESULTS: The device was placed within the insufflated abdomen of a live anesthetized pig to evaluate mobility performance on a planar tissue surface, as well as within the cecum to evaluate mobility performance in a collapsed lumen. The tRCE was capable of forward and reverse mobility for both planar and collapsed lumen tissue environments. Also, using an onboard visual system, the tRCE was capable of demonstrating visual feedback within an insufflated, anesthetized porcine abdomen. CONCLUSION: Proof-of-concept in vivo tRCE mobility using micro-patterned PDMS treads was shown. This suggests that a similar method could be implemented in future smaller, faster, and untethered RCEs.


Assuntos
Cápsulas Endoscópicas , Robótica/instrumentação , Animais , Desenho de Equipamento , Suínos
10.
Surg Innov ; 19(2): 123-9, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21914703

RESUMO

In this work, the authors designed, built, and tested a novel port camera system for single port access (SPA) laparoscopic surgery. This SPA Port Camera device integrates the monitor, laparoscopic camera, and light source into an inexpensive, portable cannula port. The device uses a 2-channel SPA port inserted through an umbilical incision, similar to traditional SPA. After insertion into a channel, the device deploys a small camera module and LED lamp in vivo. An integrated, on-patient LCD provides the view of the surgical site. The design intent of the port camera is to enhance SPA by (a) reducing the size of the SPA port through the elimination of the dedicated laparoscope channel; (b) reducing equipment cost by integrating an inexpensive CMOS sensor and LED lamp at the port tip; (c) eliminating the need for an assistant who operates the laparoscope; and (d) mechanically coupling the camera, tool port, and on-patient LCD screen. The effectiveness of the device was evaluated by comparing the video performance with a leading industry laparoscope and by performing a user evaluation study and live porcine surgery with the device. Effectiveness of the device was mixed. Overall video system performance of the device is better than an industry standard high-definition laparoscope, implying that significant cost savings over a traditional system are possible. Participant study results suggest that simulated laparoscopic tasks are as efficient with the SPA Port Camera as they are with a typical SPA configuration. However, live surgery revealed several shortcomings of the SPA Port Camera.


Assuntos
Laparoscópios , Laparoscopia/instrumentação , Laparoscopia/métodos , Gravação em Vídeo/instrumentação , Análise de Variância , Animais , Colecistectomia/instrumentação , Colecistectomia/métodos , Desenho de Equipamento , Suínos
11.
Sci Adv ; 8(25): eabn2728, 2022 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-35749508

RESUMO

Micropatterned surfaces exhibit enhanced shear traction on soft, aqueous tissue-like materials and, thus, have the potential to advance medical technology by improving the anchoring performance of medical devices on tissue. However, the fundamental mechanism underlying the enhanced shear traction is still elusive, as previous studies focused on interactions between micropatterned surfaces and rigid substrates rather than soft substrates. Here, we present a particle tracking method to experimentally measure microscale three-dimensional (3D) deformation of a soft hydrogel in normal and shear contact with arrays of microscale pillars. The measured 3D strain and stress fields reveal that the lateral contact between each individual pillar and the deformed hydrogel substrate governs the shear response. Moreover, by comparing pillars with different cross-sectional geometries, we observe experimental evidence that the shear traction of a pillar on the hydrogel substrate is sensitive to the convex features of its leading edge in the shear direction.

12.
J Biomech Eng ; 133(9): 091010, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22010745

RESUMO

In this work we present test methods, devices, and preliminary results for the mechanical characterization of the small bowel for intra luminal robotic mobility. Both active and passive forces that affect mobility are investigated. Four investigative devices and testing methods to characterize the active and passive forces are presented in this work: (1) a novel manometer and a force sensor array that measure force per cm of axial length generated by the migrating motor complex, (2) a biaxial test apparatus and method for characterizing the biomechanical properties of the duodenum, jejunum, and ileum, (3) a novel in vitro device and protocol designed to measure the energy required to overcome the self-adhesivity of the mucosa, and (4) a novel tribometer that measures the in vivo coefficient of friction between the mucus membrane and the robot surface. The four devices are tested on a single porcine model to validate the approach and protocols. Mean force readings per cm of axial length of intestine that occurred over a 15 min interval in vivo were 1.34 ± 0.14 and 1.18 ± 0.22 N cm(-1) in the middle and distal regions, respectively. Based on the biaxial stress/stretch tests, the tissue behaves anisotropically with the circumferential direction being more compliant than the axial direction. The mean work per unit area for mucoseparation of the small bowel is 0.08 ± 0.03 mJ cm(-2). The total energy to overcome mucoadhesion over the entire length of the porcine small bowel is approximately 0.55 J. The mean in vivo coefficient of friction (COF) of a curved 6.97 cm(2) polycarbonate sled on live mucosa traveling at 1 mm s(-1) is 0.016 ± 0.002. This is slightly lower than the COF on excised tissue, given the same input parameters. We have initiated a comprehensive program and suite of test devices and protocols for mechanically characterizing the small bowel for in vivo mobility. Results show that each of the four protocols and associated test devices has successfully gathered preliminary data to confirm the validity of our test approach.


Assuntos
Intestino Delgado/fisiologia , Fenômenos Mecânicos , Movimento (Física) , Robótica/instrumentação , Adesivos/metabolismo , Animais , Fenômenos Biomecânicos , Mucosa Intestinal/metabolismo , Estresse Mecânico , Propriedades de Superfície , Suínos , Resistência à Tração
13.
IEEE Trans Biomed Eng ; 68(6): 1957-1968, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33296299

RESUMO

OBJECTIVE: Robotic endoscopes have the potential to dramatically improve endoscopy procedures, however current attempts remain limited due to mobility and sensing challenges and have yet to offer the full capabilities of traditional tools. Endoscopic intervention (e.g., biopsy) for robotic systems remains an understudied problem and must be addressed prior to clinical adoption. This paper presents an autonomous intervention technique onboard a Robotic Endoscope Platform (REP) using endoscopy forceps, an auto-feeding mechanism, and positional feedback. METHODS: A workspace model is established for estimating tool position while a Structure from Motion (SfM) approach is used for target-polyp position estimation with the onboard camera and positional sensor. Utilizing this data, a visual system for controlling the REP position and forceps extension is developed and tested within multiple anatomical environments. RESULTS: The workspace model demonstrates accuracy of 5.5% while the target-polyp estimates are within 5 mm of absolute error. This successful experiment requires only 15 seconds once the polyp has been located, with a success rate of 43% using a 1 cm polyp, 67% for a 2 cm polyp, and 81% for a 3 cm polyp. CONCLUSION: Workspace modeling and visual sensing techniques allow for autonomous endoscopic intervention and demonstrate the potential for similar strategies to be used onboard mobile robotic endoscopic devices. SIGNIFICANCE: To the authors' knowledge this is the first attempt at automating the task of colonoscopy intervention onboard a mobile robot. While the REP is not sized for actual procedures, these techniques are translatable to devices suitable for in vivo application.


Assuntos
Procedimentos Cirúrgicos Robóticos , Robótica , Colonoscopia , Endoscópios , Instrumentos Cirúrgicos
14.
Soft Robot ; 8(6): 673-686, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33001742

RESUMO

Soft robotics is a field of robotic system design characterized by materials and structures that exhibit large-scale deformation, high compliance, and rich multifunctionality. The incorporation of soft and deformable structures endows soft robotic systems with the compliance and resiliency that makes them well adapted for unstructured and dynamic environments. Although actuation mechanisms for soft robots vary widely, soft electrostatic transducers such as dielectric elastomer actuators (DEAs) and hydraulically amplified self-healing electrostatic (HASEL) actuators have demonstrated promise due to their muscle-like performance and capacitive self-sensing capabilities. Despite previous efforts to implement self-sensing in electrostatic transducers by overlaying sinusoidal low-voltage signals, these designs still require sensing high-voltage signals, requiring bulky components that prevent integration with miniature untethered soft robots. We present a circuit design that eliminates the need for any high-voltage sensing components, thereby facilitating the design of simple low cost circuits using off-the-shelf components. Using this circuit, we perform simultaneous sensing and actuation for a range of electrostatic transducers including circular DEAs and HASEL actuators and demonstrate accurate estimated displacements with errors <4%. We further develop this circuit into a compact and portable system that couples high voltage actuation, sensing, and computation as a prototype toward untethered multifunctional soft robotic systems. Finally, we demonstrate the capabilities of our self-sensing design through feedback control of a robotic arm powered by Peano-HASEL actuators.


Assuntos
Sistema Musculoesquelético , Robótica , Músculos , Eletricidade Estática , Transdutores
15.
J Mech Behav Biomed Mater ; 111: 103966, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32810654

RESUMO

Balloon-assisted enteroscopy procedures allow visualization and intervention in the small intestine. These balloons anchor an endoscope and/or overtube to the small intestine, allowing endoscopists to plicate the small intestine over the overtube. This procedure can extend examination deeper into the small intestine than the length of the endoscope would allow with direct examination. However, procedures are often prolonged or incomplete due to balloon slippage. Enteroscopy balloons are pressure-limited to ensure patient safety and thus, improving anchoring without increasing pressure is essential. Patterning balloon exteriors with discrete features may enhance anchoring at the tissue-balloon interface. Here, the pattern design space is explored to determine factors that influence tissue anchoring. The anchoring ability of smooth versus balloons with patterned features is investigated by experimentally measuring a peak force required to induce slippage of an inflated balloon inside ex-vivo porcine small intestine. Stiffer materials, low aspect-ratio features, and pattern area/location on the balloons significantly increase peak force compared to smooth silicone balloons. Smooth latex balloons, used for standard enteroscopy, have the lowest peak force. This work demonstrates both a method to pattern curved surfaces and that a balloon with patterned features improves anchoring against a deformable, lubricated tissue interface.


Assuntos
Endoscopia Gastrointestinal , Laparoscopia , Animais , Desenho de Equipamento , Humanos , Intestino Delgado , Silicones , Suínos
16.
Comput Methods Biomech Biomed Engin ; 12(2): 239-48, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19012064

RESUMO

In vivo surgical robot wheel and tissue interaction was studied using a nonlinear finite element model. A liver material model, derived from laboratory experiments, was implemented as a viscoelastic material. A finite element simulation of this laboratory test confirmed the accuracy of the liver material model. This material model was then used as the tissue model to study wheel performance. A helical wheel moving on the liver model was used to replicate laboratory experiments that included several different slip ratios and applied loads. The drawbar force produced in this model showed good agreement with the physical tests. These results have provided the baseline for studying how changes in wheel geometry, such as tread height, tread spacing and wheel diameter, affect drawbar force and ultimately wheel performance. These results will be used in future surgical robot wheel designs.


Assuntos
Robótica/instrumentação , Cirurgia Assistida por Computador/instrumentação , Equipamentos Cirúrgicos , Animais , Fenômenos Biomecânicos , Engenharia Biomédica , Bovinos , Simulação por Computador , Elasticidade , Desenho de Equipamento , Análise de Elementos Finitos , Técnicas In Vitro , Fígado/fisiologia , Movimento (Física) , Dinâmica não Linear , Robótica/estatística & dados numéricos , Cirurgia Assistida por Computador/estatística & dados numéricos , Equipamentos Cirúrgicos/estatística & dados numéricos , Viscosidade
17.
Stud Health Technol Inform ; 142: 117-21, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19377127

RESUMO

The use of miniature in vivo robots that fit entirely inside the peritoneal cavity represents a novel approach to laparoscopic surgery. Previous work demonstrates that both mobile and fixed-based robots can successfully operate inside the abdominal cavity. A modular wireless mobile platform has also been developed to provide surgical vision and task assistance. This paper presents an overview of recent test results of several possible surgical applications that can be accommodated by this modular platform. Applications such as a biopsy grasper, stapler and clamp, video camera, and physiological sensors have been integrated into the wireless platform and tested in vivo in a porcine model. The modular platform facilitates rapid development and conversion from one type of surgical task assistance to another. These self-contained surgical devices are much more transportable and much lower in cost than current robotic surgical assistants. These devices could ultimately be carried and deployed by non-medical personnel at the site of an injury. A remotely located surgeon could use these robots to provide critical first response medical intervention.


Assuntos
Robótica , Cirurgia Assistida por Computador , Telecomunicações , Laparoscopia/métodos , Miniaturização , Cavidade Peritoneal/cirurgia
18.
Curr Vasc Pharmacol ; 6(4): 250-7, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18855713

RESUMO

Abdominal aortic aneurysm (AAA) is a common and deadly problem. The aortic diameter increases in association with a complex remodeling process that includes changes in the structure and content of key proteins, elastin and collagen. As these changes occur, the tissue mechanical properties also change. The natural history of AAA is progressive enlargement to a point of mechanical tissue failure typically followed by death. Currently, the marker used to predict the risk of impending rupture is the largest transverse diameter. After reaching a diameter threshold of 5.5 cm the AAA needs to be surgically repaired. This criterion does not consider any patient-specific information or heterogeneity of the AAA that may, in some cases, lead to rupture before the AAA reaches the standard intervention threshold. Conversely, in many patients, continued observation beyond this threshold is safe. While no medical treatment is yet approved, doxycycline (Doxy) has been shown to greatly reduce AAA growth in animal models and has been shown to slow growth in 1 small clinical trial. While larger prospective randomized trials are needed, one unknown is what effect Doxy has on the structural integrity of the aortic wall. That is, does slowed AAA growth, by Doxy treatment, prevent rupture, or does the wall continue to weaken and the AAA instead ruptures at a smaller diameter? Using an established animal model of AAA, we begun to determine the changes in tissue mechanics compliance of the aorta as the AAA develops. Our current research is focused on verifying that these changes mimic the observed changes seen in the human population as reported by other researchers, so that we can confidently study how potential drug therapies may affect wall strength and compliance in the human population. The long-term objectives are to understand better factors related to progression of AAA and help verify that drug therapy with Doxy will decrease the chance of rupture by preventing wall weakening and maintaining function of the aorta.


Assuntos
Aorta/efeitos dos fármacos , Aneurisma da Aorta Abdominal/tratamento farmacológico , Ruptura Aórtica/prevenção & controle , Fármacos Cardiovasculares/uso terapêutico , Programas de Rastreamento/métodos , Animais , Aorta/patologia , Aneurisma da Aorta Abdominal/complicações , Aneurisma da Aorta Abdominal/patologia , Aneurisma da Aorta Abdominal/cirurgia , Ruptura Aórtica/etiologia , Ruptura Aórtica/patologia , Pesquisa Biomédica , Complacência (Medida de Distensibilidade) , Progressão da Doença , Doxiciclina/uso terapêutico , Humanos , Camundongos , Modelos Animais , Modelos Cardiovasculares , Seleção de Pacientes , Resultado do Tratamento , Procedimentos Cirúrgicos Vasculares
19.
Comput Aided Surg ; 13(2): 95-105, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-18317958

RESUMO

Advances in endoscopic techniques for abdominal procedures continue to reduce the invasiveness of surgery. Gaining access to the peritoneal cavity through small incisions prompted the first significant shift in general surgery. The complete elimination of external incisions through natural orifice access is potentially the next step in reducing patient trauma. While minimally invasive techniques offer significant patient advantages, the procedures are surgically challenging. Robotic surgical systems are being developed that address the visualization and manipulation limitations, but many of these systems remain constrained by the entry incisions. Alternatively, miniature in vivo robots are being developed that are completely inserted into the peritoneal cavity for laparoscopic and natural orifice procedures. These robots can provide vision and task assistance without the constraints of the entry incision, and can reduce the number of incisions required for laparoscopic procedures. In this study, a series of minimally invasive animal-model surgeries were performed using multiple miniature in vivo robots in cooperation with existing laparoscopy and endoscopy tools as well as the da Vinci Surgical System. These procedures demonstrate that miniature in vivo robots can address the visualization constraints of minimally invasive surgery by providing video feedback and task assistance from arbitrary orientations within the peritoneal cavity.


Assuntos
Laparoscópios , Procedimentos Cirúrgicos Minimamente Invasivos/instrumentação , Robótica/instrumentação , Cirurgia Assistida por Computador/instrumentação , Parede Abdominal/cirurgia , Animais , Colecistectomia Laparoscópica/instrumentação , Desenho de Equipamento , Humanos , Miniaturização , Peritônio/cirurgia , Suínos , Gravação em Vídeo/instrumentação
20.
Stud Health Technol Inform ; 132: 153-8, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18391277

RESUMO

The use of miniature in vivo robots that fit entirely inside the peritoneal cavity represents a novel approach to laparoscopic surgery. Previous work has demonstrated that mobile and fixed-base in vivo robots can be used to improve visualization of the surgical field and perform surgical tasks such as collecting biopsy tissue samples. All of these robots used tethers to provide for power and data transmission. This paper describes recent work focused on developing a modular wireless mobile platform that could be used for in vivo robotic sensing and manipulation applications. One vision for these types of self-contained in vivo robotic devices is that they could be easily carried and deployed by non-medical personnel at the site of an injury. Such wireless in vivo robots are much more transportable and lower cost than current robotic surgical assistants, and could ultimately allow a surgeon to become a remote first responder irrespective of the location of the patient.


Assuntos
Robótica , Cirurgia Assistida por Computador , Telemetria/instrumentação , Animais , Laparoscopia , Suínos , Estados Unidos , Interface Usuário-Computador
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