The Encyclopedia of Medical Robotics

The following sections are included:

• PREFACE
• ABOUT THE EDITOR
• CONTENTS

This chapter introduces the topic of image guidance as it applies to surgical procedures, briefly overviews the development and state of the art of these techniques, and discusses the various components necessary to enable such operations to be carried out in an efficient manner. The importance of appropriate surgical interfaces to image-guided procedures is illustrated through examples in the author’s laboratory. Limitations to existing technologies are identified, and potential opportunities presented for moving the field forward to more widespread employment in the operating room, particularly with respect to robotically-assisted procedures.

This chapter introduces general principles of various cross-sectional imaging modalities and their general applications in clinical practice. The evolution of these imaging modalities from merely providing morphological images to providing functional information is discussed. Furthermore, the technological development that combines information from several imaging modalities to provide effective minimally-invasive image-guided interventions are discussed along with safe practices in diagnostic and interventional imaging arena.

Ultrasound (US) is a versatile tool for both diagnostic and therapeutics aspects of image-guided interventions. This chapter will review some fundamentals of US, current trends in both diagnostic and therapeutic US, and future directions.

In this chapter, we introduce the basic principle, category, and devices of OCT. Combination of OCT with medical robotics and the recent biomedical applications have also been reviewed.

In this chapter, we will introduce the basics of multi-modal imaging modalities, and their advantages and disadvantages. We have also presented the application of these imaging modalities for guiding surgical applications. We will cover conventional imaging modalities like CT and MRI, and also cover some of the latest imaging modalities like Optical Coherence Tomography (OCT) and Near Infrared Imaging (NIR).

Ultrasound (US) guidance has become a dominant imaging modality for image-guided interventions because it is real time, simple to set up, has sufficient soft tissue contrast to visualize lesions, has no ionizing radiation, and is less expensive than alternatives such as computed tomography (CT) or magnetic resonance imaging (MRI). We start by outlining some of the procedures in which US guidance is in common use. Since many of these involve needle insertion, we then discuss methods of localizing and visualizing needles. We outline three US image guidance applications that illustrate the use of signal processing to improve the usability and function of US. These are image guidance for prostate procedures (biopsy, brachytherapy and surgery) for epidurals, and for the screening of deep vein thrombosis.

Estimates in autopsy studies indicate that 50% of men older than 50 years of age have prostate cancer. Systematic transrectal ultrasound (TRUS)-guided prostate biopsy is considered the standard method for prostate cancer detection and has a significant sampling error and a low sensitivity. Molecular imaging technology and new biopsy approaches are emerging to improve the detection of prostate cancer. This chapter provides an overview on molecular imaging with positron-emission tomography (PET) and magnetic resonance imaging (MRI) for prostate cancer detection and its applications in fusion targeted biopsy of the prostate. MRI/TRUS fusion targeted biopsy has become a new clinical standard for the diagnosis of prostate cancer. PET molecular image-directed, 3D ultrasound (US)-guided biopsy is a new technology that has great potential for improving the cancer detection rate and for distinguishing aggressive prostate cancer from indolent disease. Molecular imaging and fusion targeted biopsy is an active research area in prostate cancer research and can have immediate impacts on the management of prostate cancer patients.

With the recent more widespread clinical use of interventional magnetic resonance imaging (MRI), MRI-compatible robotic systems have been heralded as a new approach to assist interventional procedures to allow physicians to treat patients more accurately and effectively. Deploying robotic systems inside MRI synergizes the imaging capability of MRI and the manipulation capability of robotic assistance, formulating the “closed-loop surgery” architecture that utilizes intra-operative imaging to adjust and control the interventional plan. However, MRI imposes unique challenges due to electromagnetic interference, material incompatibility, and confined space inside the MRI bore. This chapter introduces the advantages of MRI-guided surgery and challenges associated with being compatible with the MRI environment. It provides an overview of the state-of-the- art in MRI-compatible sensors, actuators, and robotic systems with future perspectives by discussing the limitations, open questions, and challenges of the current research landscape.

In this chapter, a framework for image-guided therapy is presented that extends the conventional framework of pre-operative imaging, registration, and visualization. While reviewing conventional localization methods, the work also relays: (1) the nature of information that will guide surgeries in the future, (2) the developments in non-contact digitization, and (3) the state of interventional imaging. With respect to therapeutic delivery, while conventional registration using points, surfaces, and intensity-based methods is reviewed, the work continues with advances in: (1) interpolative image-to-physical registration, (2) physics-based image-to-physical registration, and (3) novel extensions to physics-based registration. Lastly, a comprehensive example of a novel non-rigid image-to-physical registration using sparse intra-operative data is presented within the context of image-guided liver surgery.

The use of image guidance and surgical robotics in the context of cochlear implantation (CI) has been the subject of significant research over the last decade. The utilization of this technology has been proposed and investigated at all stages of the CI procedure. Image guidance has the potential to significantly reduce the invasiveness of the surgical approach, protect the delicate structures of the inner ear when gaining access to the scala of the cochlea, and minimize trauma, as well as preserve residual hearing, during the insertion of the electrode. The scale of the region in which these interventions take place creates a number of unique challenges with respect to the accuracy, scale, and sensing capabilities of the developed systems; the progression of the methods utilized for overcoming these difficulties, as well as the techniques and systems utilized at each stage of the procedure, and future research directions are discussed in detail in the following sections.

Robotic applications in minimally-invasive surgery (MIS) have tremendously revolutionized surgical procedures by providing highly reliable and precise manipulation of surgical tools to maximize the benefits to surgery patients. Neurosurgery is the most demanding field for robotic assistance because it requires the highest level of precision, and even a very small excursion may cause considerable damage to the neural system and result in post-surgical side effects, such as extended recovery period, permanent impairment to sensory or motor functions, or even paralysis of patients. A comprehensive review of the state-of-the-art works is presented, showing that robotic neurosurgery is still at an early development stage and only a handful of neurosurgical robotic systems have been commercialized. Considering that neurosurgery is performed in a confined and highly restricted space, meso-scale steerable neurosurgical robots could be the safer alternatives to most neurosurgical systems currently in the market.

The use of robotics in surgery has grown over the past decades. The field of neurosurgery has been slow to adopt these new technologies, in part because the clear benefits of robotic neurosurgery are not yet apparent. In this chapter, two pressing neurosurgical problems — operative line-of-sight and accuracy in hardware placement — that are solvable with surgical robotics are discussed. Ideal robotic solutions to these problems are considered, followed by a discussion of relevant existing robotic systems, and a consideration of their strengths and weaknesses.

Breast magnetic resonance imaging (MRI) has been shown to be a very sensitive method for the detection of breast cancer, offers a plethora of contrast mechanisms, high image quality and has no ionizing radiation. Fueled by continuous advances in MRI, established interpretation guidelines, and an ever growing availability of magnetic resonance (MR)-compatible breast biopsy systems, MRI of the breast is gaining popularity in clinical practice. Moreover, MRI can monitor and can facilitate the regulation of thermal- and cryoablations that emerge as breast conserving therapies. Currently MRI-guided breast interventions are multistep processes performed with the patient removed from the MRI secondary to the limited access to the patient inside the high-field scanners. To address this, groundbreaking works have introduced breast-specific MR-compatible robots to extend the presence of the interventionalist inside the scanner. Innovative works have introduced technology for the stabilization of breast tissue, computational methods for MR-guidance and multi-scale tissue characterization. Despite the potential benefits, MR-compatible robotic breast interventions are not clinically practiced. This chapter details the challenges of MRI-guided breast biopsy and therapeutics, proposed robotic solutions and outlines current trends.

Improvement of imaging techniques has enabled clinicians to identify and distinguish more prostate cancers at early stage and with added confidence. These, in turn, allow the physicians as well as the patients to take well-informed treatment decisions. Over the years, image-guidance in various clinical procedures such as biopsy, surgery, radiotherapy, etc. has significantly enhanced the clinical outcome and patient’s quality of life. Further improvements in image quality, molecular imaging with new biomarkers, customized patient treatment, and robot-assisted procedures are highly desirable.

Robotic assistance for minimally-invasive cardiovascular interventions has allowed for improved control and stability of the endovascular devices over the usual manual approaches. However, the guidance of these procedures is still limited to certain imaging modalities, with a strong dependence on X-ray fluoroscopy. In this chapter, we review the current available robotic platforms for endovascular interventions and the image guidance used clinically for these procedures. Research trends into new imaging and sensing modalities for improved endovascular guidance are discussed. Finally, we conclude with open questions and future research trends in the field.

Interventional neuroradiology is a relatively new medical subspecialty dedicated to the treatment of cerebrovascular, head and neck, and spinal disease by using image-guided, minimally-invasive techniques. These image-guided, minimally-invasive procedures have the potential to reduce risks, which traditionally have been associated with open surgical approaches, thereby improving patient outcomes. There has been a dramatic growth in image-guided interventions over the last few decades, largesly due to the availability of new devices and technologies which have allowed the performance of safer and more efficient interventions. Interventional neuroradiology now plays a pivotal role in the management of neurovascular disease. The vast majority of image-guided neurovascular interventions use cerebral angiography to evaluate the cerebral blood vessels. This approach also provides an avenue to treat neurovascular disease endovascularly.

Flexible endoscopy has been the primary means for gastrointestinal screening for over 60 years with little innovation in methodology. The traditional endoscope is limited in that it induces tissue stress during examination (i.e. looping), it cannot be used to visualize the entire small bowel, and its rigidity induces patient discomfort with potential need for sedation. Wireless capsule endoscopy (WCE), introduced in 2000, is a means for visualizing the entire gastrointestinal tract; however, capsules are limited to passive movement through the bowel and have no therapeutic capability. Robotic capsule endoscopes, an embodiment of advances in on-board technology that enable sensing and active locomotion, are actively controlled diagnostic devices with additional functionalities such as sensing or therapeutics. Their locomotion has been demonstrated both via on-board locomotion mechanisms, such as wheels or legs, and externally applied magnetic fields. Although magnetic manipulation has been shown feasible in diagnostics throughout the entire gastrointestinal tract, it has been limited by longer procedure times and difficulty in steering. Recent developments in field generation and robotic manipulation of magnets suggest that, with further control development and clinical trials, robotic capsule endoscopes have the potential to become a new standard for gastrointestinal endoscopy.

Brain surgeries are high risk endeavors. While attempting to remove malignant brain lesions, surgeons may inadvertently disrupt vital neural structures or pathways, thus resulting in disability or death. The advent of image-guidance enables surgeons to visualize critical brain structures by fusing preoperative neuroimaging with intraoperative surface registration. The surgeon may then “navigate” safely through delicate corridors to achieve maximal resection of diseased tissue. In this chapter, we briefly review the principles of neuro-navigation, touching upon topics of anatomical imaging, functional imaging, tractography and minimally invasive neurosurgery. These topics are increasingly relevant as neurosurgery moves toward surgical automation, laser thermal therapy and robot-assisted procedures.

The following section is included:

• Index