Optical techniques for 3D surface reconstruction in computer-assisted laparoscopic surgery

One of the main challenges for computer-assisted surgery (CAS) is to determine the intra-opera- tive morphology and motion of soft-tissues. This information is prerequisite to the registration of multi-modal patient-specific data for enhancing the surgeon’s navigation capabilites by observ- ing beyond exposed tissue surfaces and for providing intelligent control of robotic-assisted in- struments. In minimally invasive surgery (MIS), optical techniques are an increasingly attractive approach for in vivo 3D reconstruction of the soft-tissue surface geometry. This paper reviews the state-of-the-art methods for optical intra-operative 3D reconstruction in laparoscopic surgery and discusses the technical challenges and future perspectives towards clinical translation. With the recent paradigm shift of surgical practice towards MIS and new developments in 3D opti- cal imaging, this is a timely discussion about technologies that could facilitate complex CAS procedures in dynamic and deformable anatomical regions

Progress in Probe-Based Sensing Techniques for In Vivo Diagnosis

Advancements in robotic surgery help to improve the endoluminal diagnosis and treatment with minimally invasive or non-invasive intervention in a precise and safe manner. Miniaturized probe-based sensors can be used to obtain information about endoluminal anatomy, and they can be integrated with medical robots to augment the convenience of robotic operations. The tremendous benefit of having this physiological information during the intervention has led to the development of a variety of in vivo sensing technologies over the past decades. In this paper, we review the probe-based sensing techniques for the in vivo physical and biochemical sensing in China in recent years, especially on in vivo force sensing, temperature sensing, optical coherence tomography/photoacoustic/ultrasound imaging, chemical sensing, and biomarker sensing

OPTICAL NAVIGATION TECHNIQUES FOR MINIMALLY INVASIVE ROBOTIC SURGERIES

Minimally invasive surgery (MIS) involves small incisions in a patient's body, leading to reduced medical risk and shorter hospital stays compared to open surgeries. For these reasons, MIS has experienced increased demand across different types of surgery. MIS sometimes utilizes robotic instruments to complement human surgical manipulation to achieve higher precision than can be obtained with traditional surgeries. Modern surgical robots perform within a master-slave paradigm, in which a robotic slave replicates the control gestures emanating from a master tool manipulated by a human surgeon. Presently, certain human errors due to hand tremors or unintended acts are moderately compensated at the tool manipulation console. However, errors due to robotic vision and display to the surgeon are not equivalently addressed. Current vision capabilities within the master-slave robotic paradigm are supported by perceptual vision through a limited binocular view, which considerably impacts the hand-eye coordination of the surgeon and provides no quantitative geometric localization for robot targeting. These limitations lead to unexpected surgical outcomes, and longer operating times compared to open surgery. To improve vision capabilities within an endoscopic setting, we designed and built several image guided robotic systems, which obtained sub-millimeter accuracy. With this improved accuracy, we developed a corresponding surgical planning method for robotic automation. As a demonstration, we prototyped an autonomous electro-surgical robot that employed quantitative 3D structural reconstruction with near infrared registering and tissue classification methods to localize optimal targeting and suturing points for minimally invasive surgery. Results from validation of the cooperative control and registration between the vision system in a series of in vivo and in vitro experiments are presented and the potential enhancement to autonomous robotic minimally invasive surgery by utilizing our technique will be discussed

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

A flexible access platform for robot-assisted minimally invasive surgery

Advances in Minimally Invasive Surgery (MIS) are driven by the clinical demand to reduce the invasiveness of surgical procedures so patients undergo less trauma and experience faster recoveries. These well documented benefits of MIS have been achieved through parallel advances in the technology and instrumentation used during procedures. The new and evolving field of Flexible Access Surgery (FAS), where surgeons access the operative site through a single incision or a natural orifice incision, is being promoted as the next potential step in the evolution of surgery. In order to achieve similar levels of success and adoption as MIS, technology again has its role to play in developing new instruments to solve the unmet clinical challenges of FAS. As procedures become less invasive, these instruments should not just address the challenges presented by the complex access routes of FAS, but should also build on the recent advances in pre- and intraoperative imaging techniques to provide surgeons with new diagnostic and interventional decision making capabilities. The main focus of this thesis is the development and applications of a flexible robotic device that is capable of providing controlled flexibility along curved pathways inside the body. The principal component of the device is its modular mechatronic joint design which utilises an embedded micromotor-tendon actuation scheme to provide independently addressable degrees of freedom and three internal working channels. Connecting multiple modules together allows a seven degree-of-freedom (DoF) flexible access platform to be constructed. The platform is intended for use as a research test-bed to explore engineering and surgical challenges of FAS. Navigation of the platform is realised using a handheld controller optimised for functionality and ergonomics, or in a "hands-free" manner via a gaze contingent control framework. Under this framework, the operator's gaze fixation point is used as feedback to close the servo control loop. The feasibility and potential of integrating multi-spectral imaging capabilities into flexible robotic devices is also demonstrated. A force adaptive servoing mechanism is developed to simplify the deployment, and improve the consistency of probe-based optical imaging techniques by automatically controlling the contact force between the probe tip and target tissue. The thesis concludes with the description of two FAS case studies performed with the platform during in-vivo porcine experiments. These studies demonstrate the ability of the platform to perform large area explorations within the peritoneal cavity and to provide a stable base for the deployment of interventional instruments and imaging probes

Il ruolo della fluorescenza nella valutazione della perfusione intestinale in chirurgia robotica

La deiscenza anastomotica costituisce una delle principale complicanze in chirurgia colorettale. Oggetto di studio da anni, molti sono i fattori di rischio ad essa correlati ma non su tutti è possibile intervenire riducendone il rischio d'insorgenza. Una corretta perfusione dei monconi è fondamentale per la costruzione di un'anastomosi sana e funzionale. La NIRF è una tecnica innovativa d'imaging intraoperatorio, utilizzata tra l'altro per valutare la vascolarizzazione tissutale. Nel seguente lavoro si analizza l'utilità clinica del sistema robotico Firefly Imaging Sistem nella valutazione della perfusione intestinale nel corso di chirurgia robotica resettiva del colon sinistro/retto

Fluorescence and Diffuse Reflectance Spectroscopy and Endoscopy for Tissue Analysis

Biophotonics techniques are showing great potential for practical tissue diagnosis, capable of localised optical spectroscopy as well as wide field imaging. Many of those are generally based on the same concept: the spectral information they enable to acquire encloses clues on the tissue biochemistry and biostructure and these clues carry diagnostic information. Biophotonics techniques present the added advantage to incorporate easily miniaturisable hardware allowing several modalities to be set up on the same systems and authorizing their use during minimally invasive surgery (MIS) procedures. The work presented in this thesis aims to build on these advantages to design biophotonics instruments for tissue diagnosis. Fluorescence and diffuse reflectance, the two modalities of interest in this work, were implemented in their single point spectroscopic and imaging declinations. Two “platforms”, a spectroscopic probe setup and an optical imaging laparoscope, were built; they included either one of the two aforementioned modalities or the two of them together. The spectroscopic probe system was assembled to detect lesions in the digestive tract. In its first version, the setup included a dual laser illumination system to carry out an ex vivo fluorescence study of non-alcoholic fatty liver diseases (NAFLD) in the mouse model. Outcomes of the study demonstrated that healthy livers could be distinguished from NAFLD livers with high classification accuracy. Then, the same fluorescence probe inserted in a force adaptive robotic endoscope was applied on a fluorescence phantom and a liver specimen to prove the feasibility of recording spectra at multiple points with controlled scanning pattern and probe/sample pressure (known to affect the spectra shape). This approach proposed therefore a convincing method to perform intraoperative fluorescence measurements. The fluorescence setup was subsequently modified into a combined fluorescence/diffuse reflectance spectroscopic probe and demonstrated as an efficient method to separate normal and diseased tissue samples from the human gastrointestinal tract. Following the single point spectroscopy work, imaging studies were conducted with a spectrally resolved laparoscope. The system, featuring a CCD/filter wheel unit clipped on a traditional laparoscope was validated on fluorescence phantoms and employed in two experiments. The first one, building on the spectroscopy study of the gastrointestinal tract, was originally aimed at locating tumour in the oesophagus but a lack of tissue availability prevented us from doing so. The system design and validation on fluorophores phantoms were nevertheless described. In the second one, the underarm of a pig was imaged after injection of a nerve contrast agent in order to test the feasibility of in vivo nerve delineation. Fluorescence was detected from the region of interest but no clear contrast between the nerve and the surrounding muscle tissue could be detected. Finally, the fluorescence imaging laparoscope was modified into a hyperspectral reflectance imaging laparoscope to perform tissue vasculature studies. It was first characterized and tested on haemoglobin phantoms with varying concentrations and oxygen saturations and then employed in vivo to follow the haemoglobin concentration and oxygen saturation temporal evolutions of a porcine intestine subsequently to the pig’s termination. A decrease in oxygen saturation was observed. The last experiment consisted in monitoring the tissue re-oxygenation of a rabbit uterus transplant on the recipient animal, a successful tissue re-perfusion after the graft was highlighted

In-vivo Raman spectroscopy: from basics to applications

For more than two decades, Raman spectroscopy has found widespread use in biological and medical applications. The instrumentation and the statistical evaluation procedures have matured, enabling the lengthy transition from ex-vivo demonstration to in-vivo examinations. This transition goes hand-in-hand with many technological developments and tightly bound requirements for a successful implementation in a clinical environment, which are often difficult to assess for novice scientists in the field. This review outlines the required instrumentation and instrumentation parameters, designs, and developments of fiber optic probes for the in-vivo applications in a clinical setting. It aims at providing an overview of contemporary technology and clinical trials and attempts to identify future developments necessary to bring the emerging technology to the clinical end users. A comprehensive overview of in-vivo applications of fiber optic Raman probes to characterize different tissue and disease types is also given