Nicholas A. Patronik

Preliminary evaluation of a mobile robotic device for navigation and intervention on the beating heart.

This article describes the development and preliminary testing of a mobile robotic device to facilitate minimally invasive beating-heart intrapericardial intervention. The HeartLander robot will be introduced beneath the pericardium via subxiphoid incision, adhere to the epicardium, navigate to any location, and administer therapy under the control of the physician. As compared to current robotic cardiac surgical techniques, this novel paradigm obviates immobilization of the heart and eliminates access limitations. Furthermore, it does not require lung deflation and differential ventilation and thus could enable outpatient cardiac surgery. The current HeartLander prototypes use suction to maintain prehension of the epicardium and wire actuation to perform locomotion. A fiber optic videoscope displays visual feedback to the physician, who controls the device through a joystick interface. The initial prototype demonstrated successful prehension, turning, and locomotion on open-chest, beating-heart porcine models where the pericardium was removed (N = 3). A smaller second-generation prototype with an injection system demonstrated locomotion and myocardial injection of dye, both performed with the pericardium intact (N = 3). These trials illustrate the feasibility of using a miniature mobile robot to navigate upon the beating heart and perform intrapericardial therapy.

A Miniature Mobile Robot for Navigation and Positioning on the Beating Heart

Robotic assistance enhances conventional endoscopy; yet, limitations have hindered its mainstream adoption for cardiac surgery. HeartLander is a miniature mobile robot that addresses several of these limitations by providing precise and stable access over the surface of the beating heart in a less-invasive manner. The robot adheres to the heart and navigates to any desired target in a semiautonomous fashion. The initial therapies considered for HeartLander generally require precise navigation to multiple surface targets for treatment. To balance speed and precision, we decompose any general target acquisition into navigation to the target region followed by fine positioning to each target. In closed-chest, beating-heart animal studies, we demonstrated navigation to targets located around the circumference of the heart, as well as acquisition of target patterns on the anterior and posterior surfaces with an average error of 1.7 mm. The average drift encountered during station-keeping was 0.7 mm. These preclinical results demonstrate the feasibility of precise semiautonomous delivery of therapy to the surface of the beating heart using HeartLander.

Crawling on the Heart: A Mobile Robotic Device for Minimally Invasive Cardiac Interventions

This paper describes the development and preliminary testing of a robotic device to facilitate minimally invasive beating-heart intrapericardial interventions. We propose the concept of a subxiphoid-inserted mobile robot (HeartLander) with the ability to adhere to the epicardium, navigate to any location, and administer therapy under physician control. As compared to current laparoscopic cardiac surgical techniques, this approach obviates cardiac stabilization and eliminates access limitations. Additionally, it does not require lung deflation and differential lung ventilation, and thus could open the way to outpatient cardiac therapies. The current HeartLander prototype uses suction to maintain prehension of the epicardium and wire actuation to perform locomotion. A fiber optic videoscope displays visual feedback to the physician, who controls the device through a joystick interface. A working channel provides access for the insertion of various therapeutic tools. This prototype has demonstrated successful prehension and walking during open-chest beating-heart porcine trials.

Minimally Invasive Epicardial Injections Using a Novel Semiautonomous Robotic Device

Background— We have developed a novel miniature robotic device (HeartLander) that can navigate on the surface of the beating heart through a subxiphoid approach. This study investigates the ability of HeartLander to perform in vivo semiautonomous epicardial injections on the beating heart. Methods and Results— The inchworm-like locomotion of HeartLander is generated using vacuum pressure for prehension of the epicardium and drive wires for actuation. The control system enables semiautonomous target acquisition by combining the joystick input with real-time 3-dimensional localization of the robot provided by an electromagnetic tracking system. In 12 porcine preparations, the device was inserted into the intrapericardial space through a subxiphoid approach. Ventricular epicardial injections of dye were performed with a custom injection system through HeartLander’s working channel. HeartLander successfully navigated to designated targets located around the circumference of the ventricles (mean path length=51±25 mm; mean speed=38±26 mm/min). Injections were successfully accomplished following the precise acquisition of target patterns on the left ventricle (mean injection depth=3.0±0.5 mm). Semiautonomous target acquisition was achieved within 1.0±0.9 mm relative to the reference frame of the tracking system. No fatal arrhythmia or bleeding was noted. There were no histological injuries to the heart due to the robot prehension, locomotion, or injection. Conclusions— In this proof-of-concept study, HeartLander demonstrated semiautonomous, precise, and safe target acquisition and epicardial injection on a beating porcine heart through a subxiphoid approach. This technique may facilitate minimally invasive cardiac cell transplantation or polymer therapy in patients with heart failure.

Improved Traction for a Mobile Robot Traveling on the Heart

This document describes the effects of several design parameters on the traction generated by the suction pads of a mobile robot that walks on the surface of the heart. HeartLander is a miniature mobile robot that adheres to the epicardial surface of the heart using suction, and can travel to any desired location on the heart to administer therapeutic applications. To maximize the effectiveness of locomotion, the gripper pads must provide sufficient traction to avoid slipping. Our testing setup measured the force applied to the gripper pad adhering to ovine epicardial tissue, and recorded overhead video for tracking of the pad and tissue during an extension. By synchronizing the force and video data, we were able to determine the point at which the pad lost traction and slipped during the extension. Of the pads tested, the pad with no suction grate achieved maximum traction. Increasing the extension speed up to 20 mm/s resulted in a corresponding increase in traction. Increasing the vacuum pressure also improved the traction, but the magnitude of the effect was less than the improvement gained from increasing extension speed

Development of a tethered epicardial crawler for minimally invasive cardiac therapies

This paper describes the development of a robotic surgical device to facilitate minimally invasive, beating-heart cardiac therapies that can be performed within the pericardium. The concept we propose is that the device be equipped with the ability to adhere to the surface of the epicardium and locomote to any position and orientation under the direct control of a physician. As compared to current minimally invasive cardiac robotics, our approach obviates cardiac stabilization, lung deflation, differential lung ventilation, and reinsertion of laparoscopic tools. These advantages will result in greater efficiency and reduced trauma for the administration of intrapericardial therapies. This paper describes the current design of the robotic device and presents preliminary results.

Prototype Epicardial Crawling Device for Intrapericardial Intervention on the Beating Heart

The development and preliminary testing of a device for facilitating minimally invasive beating-heart intrapericardial interventions are described. We propose the concept of an endoscopic robotic device that adheres to the epicardium by suction and navigates by crawling like an inchworm to any position on the surface under the control of a surgeon. This approach obviates cardiac stabilization, lung deflation, differential lung ventilation, and reinsertion of laparoscopic tools for accessing different treatment sites, thus offering the possibility of reduced trauma to the patient. The device has a working channel through which various tools can be introduced for treatment. The current prototype demonstrated successful prehension, turning, and locomotion on beating hearts in a limited number of trials in a porcine model.

Synchronization of epicardial crawling robot with heartbeat and respiration for improved safety and efficiency of locomotion

HeartLander is a miniature mobile robot designed to navigate over the epicardium of the beating heart for minimally invasive therapy. This paper presents a technique to decrease slippage and improve locomotion efficiency by synchronizing the locomotion with the intrapericardial pressure variations of the respiration and heartbeat cycles.

A Miniature Cable-Driven Robot for Crawling on the Heart

This document describes the design and preliminary testing of a cable-driven robot for the purpose of traveling on the surface of the beating heart to administer therapy. This methodology obviates mechanical stabilization and lung deflation, which are typically required during minimally invasive cardiac surgery. Previous versions of the robot have been remotely actuated through push-pull wires, while visual feedback was provided by fiber optic transmission. Although these early models were able to perform locomotion in vivo on porcine hearts, the stiffness of the wire-driven transmission and fiber optic camera limited the mobility of the robots. The new prototype described in this document is actuated by two antagonistic cable pairs, and contains a color CCD camera located in the front section of the device. These modifications have resulted in superior mobility and visual feedback. The cable-driven prototype has successfully demonstrated prehension, locomotion, and tissue dye injection during in vitro testing with a poultry model

Accurate positioning for intervention on the beating heart using a crawling robot

Heart failure resulting from myocardial infarct, oxygen-deprived tissue death, is a serious disease that affects over 20 million patients in the world. The precise injection of tissue-engineered materials into the infarct site is emerging as a treatment strategy to improve cardiac function for patients with heart failure. We have developed a novel miniature robotic device (HeartLander) that can act as a manipulator for precise and stable interaction with the epicardial surface of the beating heart by mounting directly to the organ. The robot can be delivered to and operate within the intrapericardial space with the chest closed, through a single small incision below the sternum. The tethered crawling device uses vacuum pressure to maintain prehension of the epicardium, and a drive wire transmission motors for actuation. An onboard electromagnetic tracking sensor enables the display of the robot location on the heart surface to the surgeon, and closed-loop control of the robot positioning to targets. In a closed-chest animal study with the pericardium intact, HeartLander demonstrated the ability to acquire a pattern of targets located on the posterior surface of the beating heart within an average of 1.7 plusmn 1.0 mm. Dye injections were performed following the target acquisitions to simulate injection therapy for heart failure. HeartLander may prove useful in the delivery of intrapericardial treatments, like myocardial injection therapy, in a precise and stable manner, which could be performed on an outpatient basis.