Surgical planning tool for robotically assisted hearing aid implantation

PURPOSE : For the facilitation of minimally invasive robotically performed direct cochlea access (DCA) procedure, a surgical planning tool which enables the surgeon to define landmarks for patient-to-image registration, identify the necessary anatomical structures and define a safe DCA trajectory using patient image data (typically computed tomography (CT) or cone beam CT) is required. To this end, a dedicated end-to-end software planning system for the planning of DCA procedures that addresses current deficiencies has been developed. METHODS :    Efficient and robust anatomical segmentation is achieved through the implementation of semiautomatic algorithms; high-accuracy patient-to-image registration is achieved via an automated model-based fiducial detection algorithm and functionality for the interactive definition of a safe drilling trajectory based on case-specific drill positioning uncertainty calculations was developed. RESULTS :    The accuracy and safety of the presented software tool were validated during the conduction of eight DCA procedures performed on cadaver heads. The plan for each ear was completed in less than 20 min, and no damage to vital structures occurred during the procedures. The integrated fiducial detection functionality enabled final positioning accuracies of [Formula: see text] mm. CONCLUSIONS :    Results of this study demonstrated that the proposed software system could aid in the safe planning of a DCA tunnel within an acceptable time

Intraoperative tissue classification methods in orthopedic and neurological surgeries: A systematic review

Accurate tissue differentiation during orthopedic and neurological surgeries is critical, given that such surgeries involve operations on or in the vicinity of vital neurovascular structures and erroneous surgical maneuvers can lead to surgical complications. By now, the number of emerging technologies tackling the problem of intraoperative tissue classification methods is increasing. Therefore, this systematic review paper intends to give a general overview of existing technologies. The review was done based on the PRISMA principle and two databases: PubMed and IEEE Xplore. The screening process resulted in 60 full-text papers. The general characteristics of the methodology from extracted papers included data processing pipeline, machine learning methods if applicable, types of tissues that can be identified with them, phantom used to conduct the experiment, and evaluation results. This paper can be useful in identifying the problems in the current status of the state-of-the-art intraoperative tissue classification methods and designing new enhanced techniques

Survey of Visual and Force/Tactile Control of Robots for Physical Interaction in Spain

Sensors provide robotic systems with the information required to perceive the changes that happen in unstructured environments and modify their actions accordingly. The robotic controllers which process and analyze this sensory information are usually based on three types of sensors (visual, force/torque and tactile) which identify the most widespread robotic control strategies: visual servoing control, force control and tactile control. This paper presents a detailed review on the sensor architectures, algorithmic techniques and applications which have been developed by Spanish researchers in order to implement these mono-sensor and multi-sensor controllers which combine several sensors

Nonlinear characterisation of power ultrasonic devices used in bone surgery

Ultrasonic cutting has existed in surgery since the 1950s. However, it was not until the end of the 20th century that advances in ultrasonic tool design, transduction and control allowed commercially viable ultrasonic cutting devices to enter the market. Ultrasonic surgical devices, like those in other power ultrasonic applications such as drilling and welding, require devices to be driven at high power to ensure sufficient output motion is produced to fulfil the application it is designed to perform. With the advent of novel surgical techniques surgeons require tuned ultrasonic tools which can reduce invasiveness while giving access to increasingly difficult to reach surgical sites. To fulfil the requirements of novel surgical procedures new tuned tools need to be designed. Meanwhile, it is well documented that power ultrasonic devices, whilst driven at high power, are inherently nonlinear and, if no attempt is made to understand and subsequently control these behaviours, it is likely that these devices will suffer from poor performance or even failure. The behaviour of the commercial ultrasonic transducer used in bone surgery (Piezosurgery® Device) is dynamically characterised through finite element and experimental methods whilst operating in conjunction with a variety of tuned inserts. Finite element analysis was used to predict modal parameters as well as stress levels within the tuned devices whilst operating at elevated amplitudes of vibration, while experimental modal analysis validated predicted resonant frequencies and mode shapes between 0-80kHz. To investigate the behaviour of tuned devices at elevated vibrational amplitudes near resonance, responses were measured whilst the device was excited via the burst sine sweep method. In an attempt to provide an understanding of the effects that geometry, material selection and wavelength of tuned assemblies have on the behaviour of an ultrasonic device, tuned inserts consisting of a simple rod horn design were characterised alongside more complex cutting inserts which are used in maxillofacial and craniofacial surgery. From these results the aim will be to develop guidelines for design of tuned inserts. Meanwhile, Langevin transducers, commonly known as sandwich or stack transducers, in their most basic form generally consist of four parts; a front mass, a back mass, a piezoceramic stack and a stud or bolt holding the parts together under a compressive pre-load. It is traditionally proposed that the piezoceramic stack is positioned at or close to the vibrational nodal point of the longitudinal mode, however, this also corresponds with the position of highest dynamic stress. It is also well documented that piezoceramic materials possess a low linear stress threshold, therefore this research, in part, investigates whether locating the piezoceramic stack away from a position of intrinsic high stress will affect the behaviour of the device. Through experimental characterisation it has been observed that the tuned devices under investigation exhibited; resonant frequency shifts, jump amplitudes, hysteretic behaviour as well as autoparametric vibration. The source of these behaviours have been found to stem from device geometry, but also from heating within the piezoceramic elements as well as joints with different joining torques

Surgical planning tool for robotically assisted hearing aid implantation

Purpose : For the facilitation of minimally invasive robotically performed direct cochlea access (DCA) procedure, a surgical planning tool which enables the surgeon to define landmarks for patient-to-image registration, identify the necessary anatomical structures and define a safe DCA trajectory using patient image data (typically computed tomography (CT) or cone beam CT) is required. To this end, a dedicated end-to-end software planning system for the planning of DCA procedures that addresses current deficiencies has been developed. Methods : Efficient and robust anatomical segmentation is achieved through the implementation of semiautomatic algorithms; high-accuracy patient-to-image registration is achieved via an automated model-based fiducial detection algorithm and functionality for the interactive definition of a safe drilling trajectory based on case-specific drill positioning uncertainty calculations was developed. Results : The accuracy and safety of the presented software tool were validated during the conduction of eight DCA procedures performed on cadaver heads. The plan for each ear was completed in less than 20min, and no damage to vital structures occurred during the procedures. The integrated fiducial detection functionality enabled final positioning accuracies of $$0.15\pm 0.08$$ 0.15 ± 0.08 mm. Conclusions : Results of this study demonstrated that the proposed software system could aid in the safe planning of a DCA tunnel within an acceptable time

Virtual Reality Simulation of Glenoid Reaming Procedure

Glenoid reaming is a bone machining operation in Total Shoulder Arthroplasty (TSA) in which the glenoid bone is resurfaced to make intimate contact with implant undersurface. While this step is crucial for the longevity of TSA, many surgeons find it technically challenging. With the recent advances in Virtual Reality (VR) simulations, it has become possible to realistically replicate complicated operations without any need for patients or cadavers, and at the same time, provide quantitative feedback to improve surgeons\u27 psycho-motor skills. In light of these advantages, the current thesis intends to develop tools and methods required for construction of a VR simulator for glenoid reaming, in an attempt to construct a reliable tool for preoperative training and planning for surgeons involved with TSA. Towards the end, this thesis presents computational algorithms to appropriately represent surgery tool and bone in the VR environment, determine their intersection and compute realistic haptic feedback based on the intersections. The core of the computations is constituted by sampled geometrical representations of both objects. In particular, point cloud model of the tool and voxelized model of bone - that is derived from Computed Tomography (CT) images - are employed. The thesis shows how to efficiently construct these models and adequately represent them in memory. It also elucidates how to effectively use these models to rapidly determine tool-bone collisions and account for bone removal momentarily. Furthermore, the thesis applies cadaveric experimental data to study the mechanics of glenoid reaming and proposes a realistic model for haptic computations. The proposed model integrates well with the developed computational tools, enabling real-time haptic and graphic simulation of glenoid reaming. Throughout the thesis, a particular emphasis is placed upon computational efficiency, especially on the use of parallel computing using Graphics Processing Units (GPUs). Extensive implementation results are also presented to verify the effectiveness of the developments. Not only do the results of this thesis advance the knowledge in the simulation of glenoid reaming, but they also rigorously contribute to the broader area of surgery simulation, and can serve as a step forward to the wider implementation of VR technology in surgeon training programs

Resonant ultrasonic bone penetrating needles

Bone biopsy is an invasive clinical procedure where a bone sample is recovered for analysis during the diagnosis of a medical condition. The procedure is performed while the patient is under either local or general anaesthesia as the patient can experience significant discomfort and possibly large haematoma due to the large axial and rotational forces applied through the needle to penetrate bone. It is well documented that power ultrasonic surgical devices offer advantages of low cutting force, high accuracy and preservation of soft tissues. This thesis details a study of the design, analysis and evaluation of a class of novel power ultrasonic needles for bone penetration, particularly biopsy. Micrometric vibrations generated at the distal tip of a full-wavelength resonant ultrasonic device are used to penetrate the bone. Both ultrasonic longitudinal (L) and longitudinal-torsional (L-T) coupled vibration have proven successful in several applications including ultrasonic surgical devices. Interest in ultrasonic bone cutting has grown since it was first introduced commercially as Piezosurgery in the 1990s. More recent studies have focused on precision cutting of bone, reducing the risk of damage to surrounding delicate tissues in comparison with manual and other powered instruments. Finite element analysis (FEA) is used to design full wavelength ultrasonic needle devices, where the geometry of the device is systematically modified to deter modal coupling by monitoring the frequency spacing between the longitudinal mode of interest and the neighbouring parasitic modes. FEA is further exploited to predict the achievable torsional displacement in a composite mode device tuned to vibrate in a longitudinal-torsional motion through degeneration of the longitudinal motion. While the L-mode device requires the operator to apply a slow backward and forward rotation and a small forward force, to maintain a forward motion and avoid imprinting, a L-T motion at the tip device could avoid this, simplifying the procedure, increasing precision and resulting in a cylindrical, less damaged hole surface. The dynamic behaviours predicted by FEA are validated through experimental modal analysis (EMA) demonstrating the effectiveness of FEA for the design of these devices. EMA is performed by exciting the ultrasonic needle device with a low power random excitation over a predetermined frequency range and measuring the vibration response using a 3D laser Doppler vibrometer (LDV) across a grid of points on the surface of the device. Harmonic analysis was used to investigate the behaviour of the devices at high excitation levels to capture the inherent nonlinearity of the tuned device. The response is captured using bi-directional frequency sweeps across the tuned mode of interest at increasing excitation levels. Ultrasonic surgical instruments typically require to be driven at high excitation levels to generate sufficient vibration amplitude to cut or aspirate tissue or seal vessels. The nonlinearities of the instrument and load presented by the target tissue result in resonance frequency shift, variation in the electric impedance and instability in the vibrational response which can negatively affect the efficacy of the instrument. A resonance tracking system was developed to monitor the voltage and current and adjust the frequency in real time to compensate for the frequency shift. Additional functionality was incorporated to allow modifications to the excitation signal shape and to enable power modulation techniques to be tested in a study of their effects on the rate of progression of the device in its target tissue. Prototype ultrasonic needle devices were evaluated in penetration tests conducted in bone mimic materials and animal bones. The devices recovered trabecular bone from the metaphysis of an ovine femur, and the biopsy samples were architecturally comparable to samples extracted using a trephine biopsy needle. The resonant needle device extracted a cortical bone sample from the central diaphysis, which is the strongest part of the bone, and the biopsy was of superior quality to the sample recovered by a trephine bone biopsy needle. The biopsy sample extracted by the resonant needle was architecturally uniform and cylindrical with an absence of chipping on the surface, suggesting that the biopsy was extracted with precision and control. To penetrate with the L mode device, the operator had to apply a slow backward and forward rotation and the small forward force, to maintain a forward motion. The rotation had to avoid imprinting of the needle tip in the bone, which otherwise resulted in the device stalling. However the L-T mode device, realised by incorporating helical cuts along the axial length, could penetrate the same animal bone sample only requiring the small forward force, hence simplifying the procedure for the operator. The L-T device also provided increased precision, resulting in a cylindrical, less damaged hole surface. Finally, a case study related to skull-based surgery is presented. The petrous apex is a pyramidal shaped structure at the anterior superior portion of the temporal bone and can be the location of tumours, cysts and lesions requiring diagnostic investigation. The petrous apex is challenging to access due to its medial location in the skull base and closeness to important neurovascular structures. An extended surgical approach removes the subject but is associated with morbidity and hence a minimally invasive procedure to access this site to retrieve a biopsy provides a valuable test case for the ultrasonic needle. Guided by the expertise and experience of an ear, nose and throat surgeon, the ultrasonic needle devices were modified and demonstrated in lab-based studies as a new technology for this bone penetration procedure

Model Driven Robotic Assistance for Human-Robot Collaboration

While robots routinely perform complex assembly tasks in highly structured factory environments, it is challenging to apply completely autonomous robotic systems in less structured manipulation tasks, such as surgery and machine assembly/repair, due to the limitations of machine intelligence, sensor data interpretation and environment modeling. A practical, yet effective approach to accomplish these tasks is through human-robot collaboration, in which the human operator and the robot form a partnership and complement each other in performing a complex task. We recognize that humans excel at determining task goals and recognizing constraints, if given sufficient feedback about the interaction between the tool (e.g., end-effector of the robot) and the environment. Robots are precise, unaffected by fatigue and able to work in environments not suitable for humans. We hypothesize that by providing the operator with adequate information about the task, through visual and force (haptic) feedback, the operator can: (1) define the task model, in terms of task goals and virtual fixture constraints through an interactive, or immersive augmented reality interface, and (2) have the robot actively assist the operator to enhance the execution time, quality and precision of the tasks. We validate our approaches through the implementations of both cooperative (i.e., hands-on) control and telerobotic systems, for image-guided robotic neurosurgery and telerobotic manipulation tasks for satellite servicing under significant time delay

A Cognitive Robot Control Architecture for Autonomous Execution of Surgical Tasks

The research on medical robotics is starting to address the autonomous execution of surgical tasks, without effective intervention of humans apart from supervision and task configuration. This paper addresses the complete automation of a surgical robot by combining advanced sensing, cognition and control capabilities, developed according to rigorous assessment of surgical require- ments, formal specification of robotic system behavior and software design and implementation based on solid tools and frame- works. In particular, the paper focuses on the cognitive control architecture and its development process, based on formal modeling and verification methods as best practices to ensure safe and reliable behavior. Full implementation of the proposed architecture has been tested on an experimental setup including a novel robot specifically designed for surgical applications, but adaptable to different selected tasks (i.e. needle insertion, wound suturing)