Automated Endoscope Length Detection

Abstract

The length of an endoscope carried by a robotic arm is determined using computer vision. The endoscope is inserted through a trocar into a body cavity and mounted to a manipulator arm. The position of a fulcrum for movement of the endoscope at the trocar site is determined using input from a force/torque sensor. While images are captured using the endoscope, the manipulator arm withdraws the distal end of the endoscope intro the trocar. Image processing is used to determine when the distal end of the trocar becomes visible in the captured images. The position of the endoscope at the point where the trocar becomes visible is recorded, and the length of the endoscope is determined based on the recorded position.

Claims

1. A method of determining a length of an endoscope carried by a robotic arm, the method comprising: mounting the endoscope to a robotic arm; inserting the distal end of the endoscope through a trocar into a body cavity; determining the position of a fulcrum for movement of the endoscope at the trocar; while capturing images using the endoscope, withdrawing the distal end of the endoscope intro the trocar' using image processing, recording the position of the endoscope when the trocar becomes visible, and determining the length of the endoscope based on the recorded position.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG. 1A is a perspective view of a prior art robot assisted surgical system;

[0011] FIG. 1B shows a scope being mounted to a scope adapter and connected with a light cable;

[0012] FIG. 1C shows the scope being inserted through a trocar into a body cavity of a patient;

[0013] FIG. 1D shows the adapter being mounted to the manipulator;

[0014] FIG. 2 is a block diagram schematically illustrating components of the disclosed system;

[0015] FIG. 3 is a flow chart schematically illustrating steps of a method for determining scope length using computer vision;

[0016] FIG. 4 is a flow chart schematically illustrating steps of a method for controlling operation of a manipulator arm following measurement of scope length.

DETAILED DESCRIPTION

[0017] Referring to FIG. 2, a system for determining scope length include the robotic manipulator 14 that supports the scope 10b. The scope 10b captures images within the body cavity within which it is positioned, and those images are displayed on an image display 23, such as the display at the surgeon console (FIG. 1A). One or more processors 30 controls motion of the manipulator. The one or more processors 30 are also programmed with instructions for endoscope length detection which, when executed, carry out the following: [0018] receive image data captured by the scope while causing the manipulator to retract the scope within the body cavity [0019] determine when the distal tip of the trocar T is visible in the image data; and [0020] receive kinematic data from the manipulator arm, and [0021] determine the length of the endoscope using the kinematic data.

[0022] The one or more processors may provide other functions as well. For example they might also receive user input from the input devices corresponding to the desired movement of the scope once surgery has begun in the body cavity, and the robotic manipulator is caused to manipulate the surgical instruments accordingly. As discussed, the manipulator may also be controlled using a control algorithm according to which image processing is used to track and cause the scope to follow one of the other surgical instruments being used during surgery so as to maintain that instrument within the visual field displayed on the display 23.

[0023] A basic implementation of the automated homing routine for endoscope length detection is described as follows and depicted schematically in FIG. 3. During the Set Fulcrum process for the robotic arm to which the endoscope is mounted, the bedside scrubbed OR staff will place the endoscope into the trocar T positioned through an incision in the body cavity and mount it to the manipulator, and the system will determine the position of the fulcrum as described in US 2010/0094312. After the fulcrum is set, the homing routine will begin. During the homing routine, the endoscope is actively capturing images. The arm will retract the endoscope from the trocar until the end of the trocar is just visible in the endoscope view. Image processing is applied to the images captured by the endoscope and is used to identify the end of the trocar in the captured images. When the end of the trocar is recognized using image processing, the system uses kinematic information from the arm to record the distance between the distal end of the endoscope and the fulcrum.

[0024] What happens next is dependent on other features of the system. In general, the measured length is compared with the scope length that was input to the system. If the system is one in which the endoscope is mounted to the robotic arm using an adapter that is equipped to communicate information regarding the scope (or other instrument mounted using the adaptor) to the system (e.g. using an RFID tag read by a sensor on the robotic arm, bar code or QR code read by a reader on the arm etc.) the determined distance may be checked against the endoscope length stored in/on the adapter (e.g. on the adapter's RFID chip). If a user entered the scope length information using an input device, the determined distance is checked against that length. If there is a sufficiently large mismatch in the measured length and the expected length of the endoscope, it can be determined that the user did not correctly enter the scope length or select the correct adapter (which would have correctly identified the endoscope length) for the scope mounted to the manipulator. The system can then ignore the input length or information stored in the adapter's RFID chip and instead use the appropriate endoscope control information (length, mass, center of mass, etc.) based on the measured length. In other embodiments, for example where the adapter does not communicate instrument/endoscope parameters to the system, the system could rely on the endoscope control information stored in the system's memory for endoscopes of that length.

[0025] If desired, following the homing routine, the system may cause the robotic arm to move the endoscope back to its initial position and orientation (the position before the homing routine was conducted). Returning the endoscope to its initial position would likely be preferred over leaving the endoscope at the distal end of the trocar and requiring either the bedside scrubbed OR staff or the surgeon to return the endoscope to its initial position. The endoscope could be safely moved in an automated process by following the same path that was taken to reach the end of the trocar (in reverse) while preventing movement of other arms to minimize risk of collision.

[0026] In a first alternative embodiment, the manipulator arm may be used to sweep the endoscope within the body cavity, relative to the fulcrum. In this embodiment, length is calculated based on how much sweep occurs outside of the trocar. In addition, or as an alternative method to those described above, the endoscope may be removed from the trocar, and the force/torque sensor in the arm may be used to measure the weight of the endoscope. In this embodiment, the weight of the endoscope is compared with weights of endoscopes of various lengths in the system memory, and the system determines which length endoscope is being used.