PLAFOKON: a new concept for a patient-individual and intervention-specific flexible surgical platform

Background Research in the field of surgery is mainly driven by aiming for trauma reduction as well as for personalized treatment concepts. Beyond laparoscopy, other proposed approaches for further reduction of the therapeutic trauma have failed to achieve clinical translation, with few notable exceptions. We believe that this is mainly due to a lack of flexibility and high associated costs. We aimed at addressing these issues by developing a novel minimally invasive operating platform and a preoperative design workflow for patient-individual adaptation and cost-effective rapid manufacturing of surgical manipulators. In this article, we report on the first in-vitro cholecystectomy performed with our operating platform. Methods The single-port overtube (SPOT) is a snake-like surgical manipulator for minimally invasive interventions. The system layout is highly flexible and can be adapted in design and dimensions for different kinds of surgery, based on patient- and disease-specific parameters. For collecting and analyzing this data, we developed a graphical user interface, which assists clinicians during the preoperative planning phase. Other major components of our operating platform include an instrument management system and a non-sterile user interface. For the trial surgery, we used a validated phantom which was further equipped with a porcine liver including the gallbladder. Results Following our envisioned preoperative design workflow, a suitable geometry of the surgical manipulator was determined for our trial surgery and rapidly manufactured by means of 3D printing. With this setup, we successfully performed a first in-vitro cholecystectomy, which was completed in 78 min. Conclusions By conducting the trial surgery, we demonstrated the effectiveness of our PLAFOKON operating platform. While some aspects – especially regarding usability and ergonomics – can be further optimized, the overall performance of the system is highly promising, with sufficient flexibility and strength for conducting the necessary tissue manipulations.

Design and development of sensorless based 5-DOF bilaterally controlled surgical manipulator: A prototype

Minimally invasive surgery (MIS) is one of the most challenging tasks in surgical procedures due to the lack of visibility of the surgical area, instrument orientation, and depth perception. A tele-operated robot assisted minimally invasive surgery is developed to enhance a surgeon's hand dexterity and accuracy. To perform MIS, the surgeon controls a slave manipulator via a master manipulator, so the force feedback and motion feedback are required to imitate an amount of action and reaction force between master and slave manipulator. The complicated MIS requires more complex surgical manipulator with multi DOFs and multiple force feedback. The limitation of multiple DOFs force feedback is a bandwidth of torque sensors. Therefore, this study proposes a sensorless based 5-DOF Bilaterally controlled surgical manipulation. In this research disturbance observer (DOB) is used to identify the internal disturbance of the system, which is used to estimate the reaction torque. This research mainly focuses on a 5-DOF bilaterally controlled surgical manipulator to maintain a position and additional force. The result of torque error in contact motion is less than 2%, the non-contact motion error is not over 5%, and it is evident that the error is always less than 0.3% for the position response.

A Monolithic Compliant Continuum Manipulator: A Proof-of-Concept Study

Continuum robots have the potential to form an effective interface between the patient and surgeon in minimally invasive procedures. Magnetic actuation has the potential for accurate catheter steering, reducing tissue trauma and decreasing radiation exposure. In this paper, a new design of a monolithic metallic compliant continuum manipulator is presented, with flexures for precise motion. Contactless actuation is achieved using time-varying magnetic fields generated by an array of electromagnetic coils. The motion of the manipulator under magnetic actuation for planar deflection is studied. The mean errors of the theoretical model compared to experiments over three designs are found to be 1.9 mm and 5.1 deg in estimating the in-plane position and orientation of the tip of the manipulator, respectively, and 1.2 mm for the whole shape of the manipulator. Maneuverability of the manipulator is demonstrated by steering it along a path of known curvature and also through a gelatin phantom, which is visualized in real time using ultrasound imaging, substantiating its application as a steerable surgical manipulator.