Surgical and Interventional Robotics: Part III: Surgical Assistance Systems

Robotic wireless capsule endoscopy: recent advances and upcoming technologies

Wireless capsule endoscopy (WCE) offers a non-invasive evaluation of the digestive system, eliminating the need for sedation and the risks associated with conventional endoscopic procedures. Its significance lies in diagnosing gastrointestinal tissue irregularities, especially in the small intestine. However, existing commercial WCE devices face limitations, such as the absence of autonomous lesion detection and treatment capabilities. Recent advancements in micro-electromechanical fabrication and computational methods have led to extensive research in sophisticated technology integration into commercial capsule endoscopes, intending to supersede wired endoscopes. This Review discusses the future requirements for intelligent capsule robots, providing a comparative evaluation of various methods' merits and disadvantages, and highlighting recent developments in six technologies relevant to WCE. These include near-field wireless power transmission, magnetic field active drive, ultra-wideband/intrabody communication, hybrid localization, AI-based autonomous lesion detection, and magnetic-controlled diagnosis and treatment. Moreover, we explore the feasibility for future "capsule surgeons".

Foot-Controlled Robot-Enabled EnDOscope Manipulator (FREEDOM) for Sinus Surgery: Design, Control, and Evaluation

Despite successful clinical applications, teleoperated robotic surgical systems face particular limitations in the functional endoscopic sinus surgery (FESS) in terms of incompatible instrument dimensions and robot set-up. The endoscope remains manually handled by an assistant when the surgeon performs bimanual operations. This paper introduces the development of the Foot-controlled Robot-Enabled EnDOscope Manipulator (FREEDOM) designed for FESS. The system features clinical considerations that inform the design for providing reliable and safe endoscope positioning with minimal obstruction to the routine practice. The robot structure is modular and compact to ensure coaxial instrument manipulation through the nostril for manual procedures. To avoid rigid endoscope motions, a new compliant endoscope holder is proposed that passively limits the lens-tissue contact forces under collisions for patient-side protection. To facilitate hands-free endoscope manipulation that imposes minimal distractions to the surgeon, a foot-wearable interface is further designed to relieve the assistant's workload. The foot control method owns a short learning curve (mean 3.4 mins), and leads the task to be more ergonomic and surgeon-centered. Cadaver and clinical studies were both conducted to evaluate the surgical applicability of the FREEDOM to assist endoscope manipulation in FESS. The system was validated to be safe (IEC-60601-1) and easy for set up (mean 3.6 mins), from which the surgeon could perform various three-handed procedures alone in FESS without disrupting the routine practice.

Shape memory alloy reinforced 5 mm ultra-thin rigid link surgical instrument with force-feedback

We report the development of a rigid link surgical instrument for surgical robotics. The device is only 5 mm in diameter and equipped with a shape memory alloy for better gripping, which avoids the use of mechanical gears. This ultra-thin instrument has a unique force sensor mount at the gripper to capture forces as low as 288 mN from the surgical site. The gripper is controlled by a 0.5 mm cable that drives the 3-Degrees of Freedom movement for the dexterity. This mechanically robust instrument can pave the way for the realisation of compact and low cost surgical instruments for real world applications in medical robotics.

Current Capabilities and Development Potential in Surgical Robotics

Commercial surgical robots have been in clinical use since the mid-1990s, supporting surgeons in various tasks. In the past decades, many systems emerged as research platforms, and a few entered the global market. This paper summarizes the currently available surgical systems and research directions in the broader field of surgical robotics. The widely deployed teleoperated manipulators aim to enhance human cognitive and physical skills and provide smart tools for surgeons, while image-guided robotics focus on surpassing human limitations by introducing automated targeting and treatment delivery methods. Both concepts are discussed based on prototypes and commercial systems. Through concrete examples the possible future development paths of surgical robots are illustrated. While research efforts are taking different approaches to improve the capacity of such systems, the aim of this survey is to assess their maturity from the commercialization point of view.

Coaxial needle insertion assistant with enhanced force feedback

Many medical procedures involving needle insertion into soft tissues, such as anesthesia, biopsy, brachytherapy, and placement of electrodes, are performed without image guidance. In such procedures, haptic detection of changing tissue properties at different depths during needle insertion is important for needle localization and detection of subsurface structures. However, changes in tissue mechanical properties deep inside the tissue are difficult for human operators to sense, because the relatively large friction force between the needle shaft and the surrounding tissue masks the smaller tip forces. A novel robotic coaxial needle insertion assistant, which enhances operator force perception, is presented. This one-degree-of-freedom cable-driven robot provides to the operator a scaled version of the force applied by the needle tip to the tissue, using a novel design and sensors that separate the needle tip force from the shaft friction force. The ability of human operators to use the robot to detect membranes embedded in artificial soft tissue was tested under the conditions of 1) tip force and shaft force feedback, and 2) tip force only feedback. The ratio of successful to unsuccessful membrane detections was significantly higher (up to 50%) when only the needle tip force was provided to the user.

A fully sensorized cooperative robotic system for surgical interventions

In this research a fully sensorized cooperative robot system for manipulation of needles is presented. The setup consists of a DLR/KUKA Light Weight Robot III especially designed for safe human/robot interaction, a FD-CT robot-driven angiographic C-arm system, and a navigation camera. Also, new control strategies for robot manipulation in the clinical environment are introduced. A method for fast calibration of the involved components and the preliminary accuracy tests of the whole possible errors chain are presented. Calibration of the robot with the navigation system has a residual error of 0.81 mm (rms) with a standard deviation of ±0.41 mm. The accuracy of the robotic system while targeting fixed points at different positions within the workspace is of 1.2 mm (rms) with a standard deviation of ±0.4 mm. After calibration, and due to close loop control, the absolute positioning accuracy was reduced to the navigation camera accuracy which is of 0.35 mm (rms). The implemented control allows the robot to compensate for small patient movements.

Experimental evaluation of a coaxial needle insertion assistant with enhanced force feedback

During needle insertion in soft tissue, detection of change in tissue properties is important both for diagnosis to detect pathological tissue and for prevention to avoid puncture of important structures. The presence of a membrane located deep inside the tissue results in a relatively small force variation at the needle tip that can be masked by relatively large friction force between the needle shaft and the surrounding tissue. Also, user perception of force can be limited due to the overall small force amplitude in some applications (e.g. brain surgery). A novel robotic coaxial needle insertion assistant was developed to enhance operator force perception. The coaxial needle separates the cutting force at the needle tip from shear friction on the needle shaft. The assistant is force controlled (admittance control), providing the operator with force feedback that is a scaled version of the force applied by the needle tip to the tissue. The effectiveness of the assistant in enhancing the detection of different tissue types was tested experimentally. Users were asked to blindly insert a needle into artificial tissues with membranes at various depths under two force feedback conditions: (1) shaft and tip force together, and (2) only tip force. The ratio of successful to unsuccessful membrane detection was significantly higher when only the needle tip force is displayed to the user. The system proved to be compliant with the clinical applications requirements.

Future perspectives in robotic surgery

• Robotics of the current day have advanced significantly from early computer-aided design/manufacturing systems to modern master-slave robotic systems that replicate the surgeon's exact movements onto robotic instruments in the patient. • Globally >300,000 robotic procedures were completed in 2010, including ≈98,000 robot-assisted radical prostatectomies. • Broadening applications of robotics for urological procedures are being investigated in both adult and paediatric urology. • The use of the current robotic system continues to be further refined. Increasing experience has optimized port placement reducing arm collisions to allow for more expedient surgery. Improved three-dimensional camera magnification provides improved intraoperative identification of structures. • Robotics has probably improved the learning curve of laparoscopic surgery while still maintaining its patient recovery advantages and outcomes. • The future of robotic surgery will take this current platform forward by improving haptic (touch) feedback, improving vision beyond even the magnified eye, improving robot accessibility with a reduction of entry ports and miniaturizing the slave robot. • Here, we focus on the possible advancements that may change the future landscape of robotic surgery.

Surgical vision

The emergence of Minimal Access Surgery (MAS) as a paradigm in modern healthcare treatment has created new challenges and opportunities for automated image understanding and computer vision. In MAS, images recovered from inside the body using specialized devices are used to visualize and operate on the surgical site but they can also be used to computationally infer in vivo 3D tissue surface shape, soft-tissue morphology, and surgical instrument motion. This information is important for facilitating in vivo biophotonic imaging modalities where the interaction between light and tissue is used to infer the structural and functional properties of the tissue. This article provides a review of the literature for computer vision and image understanding techniques applied to MAS images. The focus of this article is to elucidate a perspective on how computer vision techniques can be used to support and enhance the capabilities of biophotonic imaging modalities during surgery. Note that while MAS encompasses a variety of surgical specializations this review does not involve procedures performed in the interventional suite. The review has been carried out based on searches in the PubMed and IEEE databases using the article's keywords.

Force feedback in a piezoelectric linear actuator for neurosurgery

BACKGROUND

Force feedback in robotic minimally invasive surgery allows the human operator to manipulate tissues as if his/her hands were in contact with the patient organs. A force sensor mounted on the probe raises problems with sterilization of the overall surgical tool. Also, the use of off-axis gauges introduces a moment that increases the friction force on the bearing, which can easily mask off the signal, given the small force to be measured.

METHODS

This work aims at designing and testing two methods for estimating the resistance to the advancement (force) experienced by a standard probe for brain biopsies within a brain-like material. The further goal is to provide a neurosurgeon using a master-slave tele-operated driver with direct feedback on the tissue mechanical characteristics. Two possible sensing methods, in-axis strain gauge force sensor and position-position error (control-based method), were implemented and tested, both aimed at device miniaturization. The analysis carried out was aimed at fulfilment of the psychophysics requirements for force detection and delay tolerance, also taking into account safety, which is directly related to the last two issues. Controller parameters definition is addressed and consideration is given to development of the device with integration of a haptic interface.

RESULTS

Results show better performance of the control-based method (RMSE < 0.1 N), which is also best for reliability, sterilizability, and material dimensions for the application addressed.

CONCLUSIONS

The control-based method developed for force estimation is compatible with the neurosurgical application and is also capable of measuring tissue resistance without any additional sensors. Force feedback in minimally invasive surgery allows the human operator to manipulate tissues as if his/her hands were in contact with the patient organs.