Laparoscopic Camera Based on an Orthogonal Magnet Arrangement

Abstract

Abstract-In this paper, we present for the first time a magnetic anchoring-actuation link with an auto-flip feature. This orthogonal magnetic arrangement relies on the placement of two permanent magnets such that their magnetic moments are respectfully orthogonal. Though the arrangement may have many applications, in this study we integrate it in a magnetic camera for laparoscopic pediatric surgery. Upon insertion through a trocar incision, the 5.5 mm diameter and 35 mm length magnetic camera is coupled with an external robotic controller and displaced from the port thus preventing clutter of the surgical workspace. The device allows for manual lateral translation as well as robotically controlled tilt and pan, resulting in four degrees of freedom. The auto-flip feature prevents the need for image adjustment in software as the camera tilts through its hemispherical workspace. A static model that relates an input external control tilt and output camera tilt has been developed and validated. Favorable results during bench and canine cadaver evaluation suggest promise for the proposed magnetic camera to improve the state of art in laparoscopic pediatric surgery.

Independent Control of Multiple Degrees of Freedom Local Magnetic Actuators With Magnetic Cross-Coupling Compensation

“…E.g. in the case of tissue retraction [17] or motion of a laparoscopic camera [18], it would be possible to estimate the wrench applied to the tissue, or the stress in the structure of the controlled mechanism, and apply consequent control actions.…”

“…To address the problem of transmitting power to a miniaturized manipulator, the effectiveness of the LMA technique has been shown [16] while in [17] and [18] the implementation of LMA-based laparoscopic devices has been demonstrated. The LMA is based on the concept of magnetic gears [19], schematized in Fig.…”

“…The need for this approach is justified by the medical applications where the laparoscopic devices based on the LMA will undergo sterilization and difficult operational environments. Moreover, the absence of electrical components in the internal part of the laparoscopic device would result in a safer use and enhanced biocompatibility [17], [18].…”

Fine orientation control of an insertable robotic camera system for single incision laparoscopic surgery

“…11 Automatic control of 2-DoF rotational motion for an insertable camera can be achieved by using electromagnetic coils to drive internal magnet array 12 or using one motorized external magnet to drive orthogonally arranged internal magnets. 13 Both of the two designs work well for close proximity, such as 20-mm abdominal wall thickness. Considering the normal range of abdominal wall thickness, ie, 20 to 40 mm, 14 the control stability and reliability will be significantly reduced as an abdominal wall thickness increases.…”

“…Manual manipulation between external magnetic handle and internal magnet can actuate 1‐DoF rotation . Automatic control of 2‐DoF rotational motion for an insertable camera can be achieved by using electromagnetic coils to drive internal magnet array or using one motorized external magnet to drive orthogonally arranged internal magnets . Both of the two designs work well for close proximity, such as 20‐mm abdominal wall thickness.…”