
Publications
2019 |
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![]() | Amanov, Ernar Designing a robotic port system for laparo-endoscopic single-site surgery PhD Thesis Leibniz University Hannover, 2019. Abstract | Links | BibTeX | Tags: continuum robot, design, medical robotics, minimally-invasive surgery, soft robot, stiffening, tendon actuated, tendon-driven continuum robots @phdthesis{Amanov2019b, title = {Designing a robotic port system for laparo-endoscopic single-site surgery}, author = {Ernar Amanov }, url = {https://www.repo.uni-hannover.de/handle/123456789/10149}, doi = {10.15488/10087}, year = {2019}, date = {2019-10-14}, school = {Leibniz University Hannover}, abstract = {Current research and development in the field of surgical interventions aim to reduce the invasiveness by using few incisions or natural orifices in the body to access the surgical site. Considering surgeries in the abdominal cavity, the Laparo-Endoscopic Single-site Surgery (LESS) can be performed through a single incision in the navel, reducing blood loss, post-operative trauma, and improving the cosmetic outcome. However, LESS results in less intuitive instrument control, impaired ergonomic, loss of depth and haptic perception, and restriction of instrument positioning by a single incision. Robot-assisted surgery addresses these shortcomings, by introducing highly articulated, flexible robotic instruments, ergonomic control consoles with 3D visualization, and intuitive instrument control algorithms. The flexible robotic instruments are usually introduced into the abdomen via a rigid straight port, such that the positioning of the tools and therefore the accessibility of anatomical structures is still constrained by the incision location. To address this limitation, articulated ports for LESS are proposed by recent research works. However, they focus on only a few aspects, which are relevant to the surgery, such that a design considering all requirements for LESS has not been proposed yet. This partially originates in the lack of anatomical data of specific applications. Further, no general design guidelines exist and only a few evaluation metrics are proposed. To target these challenges, this thesis focuses on the design of an articulated robotic port for LESS partial nephrectomy. A novel approach is introduced, acquiring the available abdominal workspace, integrated into the surgical workflow. Based on several generated patient datasets and developed metrics, design parameter optimization is conducted. Analyzing the surgical procedure, a comprehensive requirement list is established and applied to design a robotic system, proposing a tendon-driven continuum robot as the articulated port structure. Especially, the aspects of stiffening and sterile design are addressed. In various experimental evaluations, the reachability, the stiffness, and the overall design are evaluated. The findings identify layer jamming as the superior stiffening method. Further, the articulated port is proven to enhance the accessibility of anatomical structures and offer a patient and incision location independent design.}, keywords = {continuum robot, design, medical robotics, minimally-invasive surgery, soft robot, stiffening, tendon actuated, tendon-driven continuum robots}, pubstate = {published}, tppubtype = {phdthesis} } Current research and development in the field of surgical interventions aim to reduce the invasiveness by using few incisions or natural orifices in the body to access the surgical site. Considering surgeries in the abdominal cavity, the Laparo-Endoscopic Single-site Surgery (LESS) can be performed through a single incision in the navel, reducing blood loss, post-operative trauma, and improving the cosmetic outcome. However, LESS results in less intuitive instrument control, impaired ergonomic, loss of depth and haptic perception, and restriction of instrument positioning by a single incision. Robot-assisted surgery addresses these shortcomings, by introducing highly articulated, flexible robotic instruments, ergonomic control consoles with 3D visualization, and intuitive instrument control algorithms. The flexible robotic instruments are usually introduced into the abdomen via a rigid straight port, such that the positioning of the tools and therefore the accessibility of anatomical structures is still constrained by the incision location. To address this limitation, articulated ports for LESS are proposed by recent research works. However, they focus on only a few aspects, which are relevant to the surgery, such that a design considering all requirements for LESS has not been proposed yet. This partially originates in the lack of anatomical data of specific applications. Further, no general design guidelines exist and only a few evaluation metrics are proposed. To target these challenges, this thesis focuses on the design of an articulated robotic port for LESS partial nephrectomy. A novel approach is introduced, acquiring the available abdominal workspace, integrated into the surgical workflow. Based on several generated patient datasets and developed metrics, design parameter optimization is conducted. Analyzing the surgical procedure, a comprehensive requirement list is established and applied to design a robotic system, proposing a tendon-driven continuum robot as the articulated port structure. Especially, the aspects of stiffening and sterile design are addressed. In various experimental evaluations, the reachability, the stiffness, and the overall design are evaluated. The findings identify layer jamming as the superior stiffening method. Further, the articulated port is proven to enhance the accessibility of anatomical structures and offer a patient and incision location independent design. |
2018 |
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![]() | Langer, Marlene; Amanov, Ernar; Burgner-Kahrs, Jessica Stiffening Sheaths for Continuum Robots Journal Article Soft Robotics, 5 (3), pp. 291-303, 2018. Abstract | Links | BibTeX | Tags: continuum robot, design, granular jamming, layer jamming, soft robot, stiffening @article{Langer2018, title = {Stiffening Sheaths for Continuum Robots}, author = {Marlene Langer and Ernar Amanov and Jessica Burgner-Kahrs}, doi = {10.1089/soro.2017.0060}, year = {2018}, date = {2018-06-01}, journal = {Soft Robotics}, volume = {5}, number = {3}, pages = {291-303}, abstract = {Added to their high dexterity and ability to conform to complex shapes, continuum robots can be further improved to provide safer interaction with their environment. Indeed, controlling their stiffness is one of the most challenging yet promising research topics. We propose a tubular stiffening sheath as a replaceable cover for small-diameter continuum robots to temporarily increase the stiffness in a certain configuration. In this article, we assess and compare performances of two different stiffening modalities: granular and layer jamming, provide arguments for material selection and experimental results for stiffness with respect to lateral and axial applied forces. Furthermore, we detected empirically additional effects relating sheath stiffness to material parameters and added to recent investigations in the state of the art, which are based exclusively on material roughness. Finally, we integrated the selected layer jamming material in a miniaturized sheath (13 mm outer diameter, 2.5 mm wall thickness) and covered a tendon-actuated continuum robot with it. Experimental characterization of the behavior with respect to applied external forces was performed via stiffness measurements and proved that the initial tendon-actuated continuum robot stiffness can be improved by a factor up to 24.}, keywords = {continuum robot, design, granular jamming, layer jamming, soft robot, stiffening}, pubstate = {published}, tppubtype = {article} } Added to their high dexterity and ability to conform to complex shapes, continuum robots can be further improved to provide safer interaction with their environment. Indeed, controlling their stiffness is one of the most challenging yet promising research topics. We propose a tubular stiffening sheath as a replaceable cover for small-diameter continuum robots to temporarily increase the stiffness in a certain configuration. In this article, we assess and compare performances of two different stiffening modalities: granular and layer jamming, provide arguments for material selection and experimental results for stiffness with respect to lateral and axial applied forces. Furthermore, we detected empirically additional effects relating sheath stiffness to material parameters and added to recent investigations in the state of the art, which are based exclusively on material roughness. Finally, we integrated the selected layer jamming material in a miniaturized sheath (13 mm outer diameter, 2.5 mm wall thickness) and covered a tendon-actuated continuum robot with it. Experimental characterization of the behavior with respect to applied external forces was performed via stiffness measurements and proved that the initial tendon-actuated continuum robot stiffness can be improved by a factor up to 24. |
![]() | Amanov, Ernar; Nguyen, Thien-Dang; Markmann, Steffen; Imkamp, Florian; Burgner-Kahrs, Jessica Toward a Flexible Variable Stiffness Endoport for Single-Site Partial Nephrectomy Journal Article Annals of Biomedical Engineering, 46 (10), pp. 1498-1510, 2018. Abstract | Links | BibTeX | Tags: continuum robot, design, layer jamming, minimally-invasive surgery, soft robot, tendon actuated, tendon-driven continuum robots @article{Amanov2018, title = {Toward a Flexible Variable Stiffness Endoport for Single-Site Partial Nephrectomy}, author = {Ernar Amanov and Thien-Dang Nguyen and Steffen Markmann and Florian Imkamp and Jessica Burgner-Kahrs}, doi = {10.1007/s10439-018-2060-4}, year = {2018}, date = {2018-05-31}, journal = {Annals of Biomedical Engineering}, volume = {46}, number = {10}, pages = {1498-1510}, abstract = {Laparoscopic partial nephrectomy for localized renal tumors is an upcoming standard minimally invasive surgical procedure. However, a single-site laparoscopic approach would be even more preferable in terms of invasiveness. While the manual approach offers rigid curved tools, robotic single-site systems provide high degrees of freedom manipulators. However, they either provide only a straight deployment port, lack of instrument integration, or cannot be reconfigured. Therefore, the current main shortcomings of single-site surgery approaches include limited tool dexterity, visualization, and intuitive use by the surgeons. For partial nephrectomy in particular, the accessibility of the tumors remains limited and requires invasive kidney mobilization (separation of the kidney from the surrounding tissue), resulting in patient stress and prolonged surgery. We address these limitations by introducing a flexible, robotic, variable stiffness port with several working channels, which consists of a two-segment tendon-driven continuum robot with integrated granular and layer jamming for stabilizing the pose and shape. We investigate biocompatible granules for granular jamming and demonstrate the stiffening capabilities in terms of pose and shape accuracy with experimental evaluations. Additionally, we conduct in vitro experiments on a phantom and prove that the visualization of tumors at various sites is increased up to 38% in comparison to straight endoscopes.}, keywords = {continuum robot, design, layer jamming, minimally-invasive surgery, soft robot, tendon actuated, tendon-driven continuum robots}, pubstate = {published}, tppubtype = {article} } Laparoscopic partial nephrectomy for localized renal tumors is an upcoming standard minimally invasive surgical procedure. However, a single-site laparoscopic approach would be even more preferable in terms of invasiveness. While the manual approach offers rigid curved tools, robotic single-site systems provide high degrees of freedom manipulators. However, they either provide only a straight deployment port, lack of instrument integration, or cannot be reconfigured. Therefore, the current main shortcomings of single-site surgery approaches include limited tool dexterity, visualization, and intuitive use by the surgeons. For partial nephrectomy in particular, the accessibility of the tumors remains limited and requires invasive kidney mobilization (separation of the kidney from the surrounding tissue), resulting in patient stress and prolonged surgery. We address these limitations by introducing a flexible, robotic, variable stiffness port with several working channels, which consists of a two-segment tendon-driven continuum robot with integrated granular and layer jamming for stabilizing the pose and shape. We investigate biocompatible granules for granular jamming and demonstrate the stiffening capabilities in terms of pose and shape accuracy with experimental evaluations. Additionally, we conduct in vitro experiments on a phantom and prove that the visualization of tumors at various sites is increased up to 38% in comparison to straight endoscopes. |