Robot Assisted Laser Osteotomy

In the scope of this thesis world\u27s first robot system was developed, which facilitates osteotomy using laser in arbitrary geometries with an overall accuracy below 0.5mm. Methods of computer and robot assisted surgery were reconsidered and composed to a workflow. Adequate calibration and registration methods are proposed. Further a methodology for transferring geometrically defined cutting trajectories into pulse sequences and optimized execution plans is developed

Feasibility of preoperative planning using anatomical facsimile models for mandibular reconstruction

BACKGROUND: Functional and aesthetic mandibular reconstruction after ablative tumor surgery continues to be a challenge even after the introduction of microvascular bone transfer. Complex microvascular reconstruction of the resection site requires accurate preoperative planning. In the recent past, bone graft and fixation plates had to be reshaped during the operation by trial and error, often a time-consuming procedure. This paper outlines the possibilities and advantages of the clinical application of anatomical facsimile models in the preoperative planning of complex mandibular reconstructions after tumor resections. METHODS: From 2003 to 2005, in the Department of Maxillofacial Surgery of the University of Udine, a protocol was applied with the preoperative realization of stereolithographic models for all the patients who underwent mandibular reconstruction with microvascular flaps. 24 stereolithographic models were realized prior to surgery before emimandibulectomy or segmental mandibulectomy. The titanium plates to be used for fixation were chosen and bent on the model preoperatively. The geometrical information of the virtual mandibular resections and of the stereolithographic models were used to choose the ideal flap and to contour the flap into an ideal neomandible when it was still pedicled before harvesting. RESULTS: Good functional and aesthetic results were achieved. The surgical time was decreased on average by about 1.5 hours compared to the same surgical kind of procedures performed, in the same institution by the same surgical team, without the aforesaid protocol of planning. CONCLUSION: Producing virtual and stereolithographic models, and using them for preoperative planning substantially reduces operative time and difficulty of the operation during microvascular reconstruction of the mandible

Medical Robotics

The first generation of surgical robots are already being installed in a number of operating rooms around the world. Robotics is being introduced to medicine because it allows for unprecedented control and precision of surgical instruments in minimally invasive procedures. So far, robots have been used to position an endoscope, perform gallbladder surgery and correct gastroesophogeal reflux and heartburn. The ultimate goal of the robotic surgery field is to design a robot that can be used to perform closed-chest, beating-heart surgery. The use of robotics in surgery will expand over the next decades without any doubt. Minimally Invasive Surgery (MIS) is a revolutionary approach in surgery. In MIS, the operation is performed with instruments and viewing equipment inserted into the body through small incisions created by the surgeon, in contrast to open surgery with large incisions. This minimizes surgical trauma and damage to healthy tissue, resulting in shorter patient recovery time. The aim of this book is to provide an overview of the state-of-art, to present new ideas, original results and practical experiences in this expanding area. Nevertheless, many chapters in the book concern advanced research on this growing area. The book provides critical analysis of clinical trials, assessment of the benefits and risks of the application of these technologies. This book is certainly a small sample of the research activity on Medical Robotics going on around the globe as you read it, but it surely covers a good deal of what has been done in the field recently, and as such it works as a valuable source for researchers interested in the involved subjects, whether they are currently “medical roboticists” or not

3D Laser-and-tissue Agnostic Data-driven Method for Robotic Laser Surgical Planning

In robotic laser surgery, shape prediction of an one-shot ablation cavity is an important problem for minimizing errant overcutting of healthy tissue during the course of pathological tissue resection and precise tumor removal. Since it is difficult to physically model the laser-tissue interaction due to the variety of optical tissue properties, complicated process of heat transfer, and uncertainty about the chemical reaction, we propose a 3D cavity prediction model based on an entirely data-driven method without any assumptions of laser settings and tissue properties. Based on the cavity prediction model, we formulate a novel robotic laser planning problem to determine the optimal laser incident configuration, which aims to create a cavity that aligns with the surface target (e.g. tumor, pathological tissue). To solve the one-shot ablation cavity prediction problem, we model the 3D geometric relation between the tissue surface and the laser energy profile as a non-linear regression problem that can be represented by a single-layer perceptron (SLP) network. The SLP network is encoded in a novel kinematic model to predict the shape of the post-ablation cavity with an arbitrary laser input. To estimate the SLP network parameters, we formulate a dataset of one-shot laser-phantom cavities reconstructed by the optical coherence tomography (OCT) B-scan images for the data-driven modelling. To verify the method. The learned cavity prediction model is applied to solve a simplified robotic laser planning problem modelled as a surface alignment error minimization problem. The initial results report (91.1 +- 3.0)% 3D-cavity-Intersection-over-Union (3D-cavity-IoU) for the 3D cavity prediction and an average of 97.9% success rate for the simulated surface alignment experiments

The beginning of a new era in bone surgery Effectiveness and clinical application of a cold-ablation and robot-guided laser osteotome

Most industrial laser applications utilize computer and robot assistance, for guidance, safety, repeatability, and precision. For industrial applications, the increase in throughput and the processing speed are in the foreground. Nevertheless, these tools cannot just be transferred into clinical and surgical use because the focus in surgical interventions is on the exact implementation of a unique plan. The patient, as an inaccurately defined workpiece, with its individual anatomy and pathology, ultimately needs a single lot planning. Nowadays, medical laser systems are hand driven. The possibility of working precision, as used in industry lasers, is not exhausted. Therefore, medical laser beams have to be coupled to robot guidance. But due to the over-size of commercially available tools, efficient and ergonomic work in an operating room is impossible. Integration of the systems such as the laser source, and the robot arm are needed. Another key issue for the accuracy of the robotic arm is the inclusion of a tracking system. All these issues were encountered developing CARLO®: a Cold-Ablation and Robot-guided Laser Osteotome. This PhD thesis is divided in three parts: - an in-vivo study in sheep, - an in-vitro / wetlab study on human cadavers, and - a theoretical-experimental study to evaluate biomechanical changes in different osteotomy pattern. To test the applicability of the system in an operation theatre similar environment, an in-vivo animal trial was performed. Additionally, we wanted to demonstrate that bone healing after laser osteotomy is not impaired compared to the standard tool the piezo-osteotome. In terms of new mineralized bone formation, histological and micro-CT analysis showed clearly a higher tendency towards the acceleration of the healing process in the laser group. Additionally, no signs of bone necrosis were seen. In addition to the pure functioning of the device, the applicability in the clinic is important for technology to prevail. Therefore, dummy tests for the ergonomics and cadaver tests for the simulation of "real" operations in the cranio-maxillofacial field were performed. Wetlab tests were conducted on human cadavers where different macro-retentive osteotomy patterns were performed. It could be demonstrated that our prototype shows advantages over the current state of the art cutting tools, e.g. reduced bone loss, precise and real-time navigated execution of predefined geometries of freely selected osteotomy patterns. This advantage can be implemented in another indication of our prototype in the cranio-maxillofacial field: in craniosynostosis surgery. We performed a study using finite element analysis to simulate incomplete osteotomies on the inner side of the bone flap to facilitate the re-shaping (skull molding). This biomechanical analysis intended to create basic knowledge in terms of the best stress vs. force relation to obtain the largest projected bone surface. Moreover, a human multicenter study is ready to start for the clinical introduction of the cold-ablation and robot-guided laser osteotome and to gain more experience and information for future work

Clinical situations for which 3D printing is considered an appropriate representation or extension of data contained in a medical imaging examination: Neurosurgical and otolaryngologic conditions

BACKGROUND: Medical three dimensional (3D) printing is performed for neurosurgical and otolaryngologic conditions, but without evidence-based guidance on clinical appropriateness. A writing group composed of the Radiological Society of North America (RSNA) Special Interest Group on 3D Printing (SIG) provides appropriateness recommendations for neurologic 3D printing conditions. METHODS: A structured literature search was conducted to identify all relevant articles using 3D printing technology associated with neurologic and otolaryngologic conditions. Each study was vetted by the authors and strength of evidence was assessed according to published guidelines. RESULTS: Evidence-based recommendations for when 3D printing is appropriate are provided for diseases of the calvaria and skull base, brain tumors and cerebrovascular disease. Recommendations are provided in accordance with strength of evidence of publications corresponding to each neurologic condition combined with expert opinion from members of the 3D printing SIG. CONCLUSIONS: This consensus guidance document, created by the members of the 3D printing SIG, provides a reference for clinical standards of 3D printing for neurologic conditions

Magnetic Resonance-Guided Focused Ultrasound in Neurosurgery: Taking Lessons From the Past to Inform the Future

Magnetic resonance-guided focused ultrasound (MRgFUS) is a new emerging neurosurgical procedure applied in a wide range of clinical fields. It can generate high-intensity energy at the focal zone in deep body areas without requiring incision of soft tissues. Although the effectiveness of the focused ultrasound technique had not been recognized because of the skull being a main barrier in the transmission of acoustic energy, the development of hemispheric distribution of ultrasound transducer phased arrays has solved this issue and enabled the performance of true transcranial procedures. Advanced imaging technologies such as magnetic resonance thermometry could enhance the safety of MRgFUS. The current clinical applications of MRgFUS in neurosurgery involve stereotactic ablative treatments for patients with essential tremor, Parkinson's disease, obsessive-compulsive disorder, major depressive disorder, or neuropathic pain. Other potential treatment candidates being examined in ongoing clinical trials include brain tumors, Alzheimer's disease, and epilepsy, based on MRgFUS abilities of thermal ablation and opening the blood-brain barrier. With the development of ultrasound technology to overcome the limitations, MRgFUS is gradually expanding the therapeutic field for intractable neurological disorders and serving as a trail for a promising future in noninvasive and safe neurosurgical care.ope

A Magnetic Laser Scanner for Endoscopic Microsurgery

Laser scanners increase the quality of the laser microsurgery enabling fast tissue ablation with less thermal damage. Such technology is part of state-of-the-art freebeam surgical laser systems. However, laser scanning has not been incorporated to fiber-based lasers yet. This is a combination that has potential to greatly improve the quality of laser microsurgeries on difficult-to-reach surgical sites. Current fiberbased tissue ablations are performed in contact with the tissue, resulting in excessive thermal damage to healthy tissue in the vicinity of the ablated tissue. This is far from ideal for delicate microsurgeries, which require high-quality tissue incisions without any thermal damage or char formation. However, the possibility to perform scanning laser microsurgery in confined workspaces is restricted by the large size of currently available actuators, which are typically located outside the patient and require direct line-of-sight to the microsurgical area. Thus, it is desired to have the laser scanning feature in an endoscopic system to provide high incision quality in hard-to-reach surgical sites. This thesis aims to introduce a new endoscopic laser scanner to perform 2D position control and high-speed scanning of a fiber-based laser for operation in narrow workspaces. It also presents a technology concept aimed at assisting in incision depth control during soft-tissue microsurgery. The main objective of the work presented in this thesis is to bring the benefits of free-beam lasers to laser-based endoscopic surgery by designing an end-effector module to be placed at the distal tip of a flexible robot arm. To this end, the design and control of a magnetic laser scanner for endoscopic microsurgeries is presented. The system involves an optical fiber, electromagnetic coils, a permanent magnet and optical lenses in a compact system for laser beam deflection. The actuation mechanism is based on the interaction between the electromagnetic field and the permanent magnets. A cantilevered optical fiber is bended with the magnetic field induced by the electromagnetic coils by creating magnetic torque on the permanent magnet. The magnetic laser scanner provides 2D position control and high-speed scanning of the laser beam. The device includes laser focusing optics to allow non-contact incisions. A proof-of-concept device was manufactured and evaluated. It includes four electromagnetic coils and two plano-convex lenses, and has an external diameter of 13 mm. A 4 74 mm2 scanning range was achieved at a 30 mm distance from the scanner tip. Computer-controlled trajectory executions demonstrated repeatable results with 75 m precision for challenging trajectories. Frequency analysis demonstrated stable response up to 33 Hz for 3 dB limit. The system is able to ablate tissue substitutes with a 1940 nm wavelength surgical diode laser. Tablet-based control interface has been developed for intuitive teleoperation. The performance of the proof-of-concept device is analysed through control accuracy and usability studies. Teleoperation user trials consisting in trajectory-following tasks involved 12 subjects. Results demonstrated users could achieve an accuracy of 39 m with the magnetic laser scanner system. For minimally invasive surgeries, it is essential to perform accurate laser position control. Therefore, a model based feed-forward position control of magnetic laser scanner was developed for automated trajectory executions. First, the dynamical model of the system was identified using the electromagnets current (input) and the laser position (output). Then, the identified model was used to perform feedforward control. Validation experiments were performed with different trajectory types, frequencies and amplitudes. Results showed that desired trajectories can be executed in high-speed scanning mode with less than 90 m (1.4 mrad bending angle) accuracy for frequencies up to 15 Hz. State-of-the-art systems do not provide incision depth control, thus the quality of such control relies entirely on the experience and visual perception of the surgeons. In order to provide intuitive incision depth control in endoscopic microsurgeries, the concept of a technology was presented for the automated laser incisions given a desired depth based on a commercial laser scanner. The technology aims at automatically controlling laser incisions based on high-level commands from the surgeon, i.e. desired incision shape, length and depth. A feed-forward controller provides (i) commands to the robotic laser system and (ii) regulates the parameters of the laser source to achieve the desired results. The controller for the incision depth is extracted from experimental data. The required energy density and the number of passes are calculated to reach the targeted depth. Experimental results demonstrate that targeted depths can be achieved with \ub1100 m accuracy, which proves the feasibility of this approach. The proposed technology has the potential to facilitate the surgeon\u2019s control over laser incisions. The magnetic laser scanner enables high-speed laser positioning in narrow and difficult-to-reach workspaces, promising to bring the benefits of scanning laser microsurgery to flexible endoscopic procedures. In addition, the same technology can be potentially used for optical fiber based imaging, enabling for example the creation of new family of scanning endoscopic OCT or hyperspectral probes

Bildverarbeitungsunterstützte Laserknochenablation am humanen Felsenbein

Für die Grenzflächenerhaltung am Innenohr als mikrochirurgische Herausforderung und wichtiger Schritt zur bestmöglichen Versorgung von Schwerhörigen mit Cochleaimplantaten wird in dieser Arbeit die bildbasierte Regelung während eines laserbasierten Knochenabtrages eingesetzt. Dabei wird der Aufbau des Systems, Bildverarbeitungsalgorithmen für die Grenzflächenerkennung, Planung, Simulation und Modellierung des mikrochirurgischen Knochenabtrages sowie die experimentelle Verifikation beschrieben