The Click-On gamma probe, a second-generation tethered robotic gamma probe that improves dexterity and surgical decision-making

Abstract

Purpose: Decision-making and dexterity, features that become increasingly relevant in (robot-assisted) minimally invasive surgery, are considered key components in improving the surgical accuracy. Recently, DROP-IN gamma probes were introduced to facilitate radioguided robotic surgery. We now studied if robotic DROP-IN radioguidance can be further improved using tethered Click-On designs that integrate gamma detection onto the robotic instruments themselves.

Methods: Using computer-assisted drawing software, 3D printing and precision machining, we created a Click-On probe containing two press-fit connections and an additional grasping moiety for a ProGrasp instrument combined with fiducials that could be video tracked using the Firefly laparoscope. Using a dexterity phantom, the duration of the specific tasks and the path traveled could be compared between use of the Click-On or DROP-IN probe. To study the impact on surgical decision-making, we performed a blinded study, in porcine models, wherein surgeons had to identify a hidden ⁵⁷Co-source using either palpation or Click-On radioguidance.

Results: When assembled onto a ProGrasp instrument, while preserving grasping function and rotational freedom, the fully functional prototype could be inserted through a 12-mm trocar. In dexterity assessments, the Click-On provided a 40% reduction in movements compared to the DROP-IN, which converted into a reduction in time, path length, and increase in straightness index. Radioguidance also improved decision-making; task-completion rate increased by 60%, procedural time was reduced, and movements became more focused.

Conclusion: The Click-On gamma probe provides a step toward full integration of radioguidance in minimal invasive surgery. The value of this concept was underlined by its impact on surgical dexterity and decision-making.

Keywords: Image-guided surgery; Performance assessment; Precision surgery; Radioguided surgery; Robotic surgery; Surgical training.

Fig. 1

Schematic overview of the Click-On gamma probe design. Attaching the Click-On gamma probe to a ProGrasp instrument essentially yields a “smart” instrument that facilitates gamma-ray detection, while at the same time preserving its grasping function

Fig. 2

Schematic overview of the Click-On gamma probe vs. the DROP-IN gamma probe. a The DROP-IN gamma probe is inserted into the abdominal cavity through the assistant trocar (12 mm) then the surgeon picks it up with the surgical instrument, allowing for 6 degrees of freedom. b The Click-On gamma probe mounted on the ProGrasp instrument is inserted together with the instrument through a standard 12-mm trocar preserving the 6 degrees of freedom of maneuverability and leaving the assistant trocar completely free. The 3D trajectories are reconstructed for probe movements using the marker-based vision tracking system

Fig. 3

Phantom evaluation of Click-On vs. DROP-IN probe. a Overview of the robot-assisted phantom setting. b, c DROP-IN and Click-On probe in action on the Phantom Plate. d, e Color-coded diagram of the movement trajectory with DROP-IN and Click-On gamma probe (red—radioactive source location, purple—collection bucket, blue—the DROP-IN probe home location in the plate for releasing and picking up, and black—transition between locations). The coordinate system is such that x- and y-axes show the image plane with the center of the image as the origin and z-axis shows the distance from the camera

Fig. 4

Track analysis of Click-On radioguidance in vivo during robot-assisted laparoscopic surgery. The 3D surface plots are based on the percentage of time spent in a specific location of the abdomen (%s/cm³) in each experiment. This is also converted into a color-coded 2D (%s/cm²; related to the color bar shown on the right) plots on the XY plane. Top row: the results of each fellow surgeon trial for finding the hidden target with palpation, bottom row: results of the same fellow surgeon with Click-On probe guidance (fellows 1 and 2 could not find the target without Click-On probe, they did find it using the probe guidance at 24 and 30 s, respectively; fellow 3 found the target with Click-On probe on the last seconds (t = 39 s); fellow 4 found it in both experiments very quickly; fellow 5 could not find it in both experiments)

Fig. 5

Augmented display of instrument positioning in the surgical field. a Overview of the operating room. b, c overlay of the density plots of X and Y components of the movement based on the time spent in each cm² of the surgical view (example shown for one surgeon searching for the hidden target with palpation and Click-On probe radioguidance, respectively)