Method and apparatus to provide updated patient images during robotic surgery

The present invention concerns imaging systems and procedures used to provide images during the course of a surgical procedure implemented by a robotic manipulator.

Robotically implemented medical procedures, commonly called robotic surgery, is in widespread use for a variety of medical interventional procedures involving many different organs of a patient. Particularly in the case of abdominal procedures, such as those involving the pancreas or the liver, the organ in question is physically moved or otherwise modified by the robotic manipulator during the course of the procedure. Such changes are designated below as geometric changes to the region or anatomy. Similar changes in the organ or the region of interest also occur at other sites within the patient.

As is well known, commercially available robotic manipulators are operated by a physician (surgeon) to execute a number of physical interactions with one or more organs during the procedure, such as grabbing, cutting, pushing, pulling, etc. It is often the case that the surgical site is resected in order to expose the organ that is being manipulated, but certain types of procedures can also be implemented with only a small incision for introducing an instrument or endoscope.

Typically a computed tomography or magnetic resonance image of the surgical site is obtained as part of a planning procedure. During the actual procedure, an endoscopic image is typically obtained, and the content of such an endoscopic image is thus limited by the field of view of the camera that is used to obtain the endoscopic image. The endoscopic image can include only contents that are within the direct line of sight of the camera and thus only the sides of organs and surrounding tissue that are facing the camera can be seen in such an image.

Although the organ of interest in the planning image can be segmented and then rotated, translated or otherwise changed in known ways at the display screen, the planning image, since it was obtained before the surgical procedure started, will not show changes in the organ itself, such as cutting thereof, that occur during the course of the surgical procedure, and also will not show changes in the position of the organ that may also occur during the course of the procedure.

Known robotic manipulators that are used in surgical procedures are operated from a control console, at which the surgeon is situated. The control console includes a number of manually operated or manipulated elements that the physician operates in the same manner as if the physician were using an instrument at the actual site of the surgery. Thus, for example, if the physician wants to implement a cutting procedure on the organ via the robotic manipulator, a scissors-like control element will be provided at the console. The corresponding cutter of the robotic manipulator is provided with appropriate force sensors, which detect forces at the organ that are applied by the robotic manipulator, and also detect forces on the robotic manipulator that are produced by the organ. This combination of forces provides haptic feedback to the surgeon at the console so that the surgeon operating the scissors-like control element will experience the same cutting force, and resistance of the organ to such a cutting force, that the surgeon would feel if the physician were directly manually operating a cutting element at the surgery site.

The same is true with regard to other types of instruments that are implemented by the robotic manipulator, such as instruments that grab the organ in order to allow the surgeon to then displace all or a portion of the organ in a selected manner.

An object of the present invention is to provide a surgeon with one or more displayed images during the course of a robotically-implemented surgical procedure that not only show the current state of the anatomy or organ that is the subject of the intervention, but also allow the surgeon, by manipulating the displayed images, to see portions of the anatomy that are not visible in a conventional endoscopic image.

This object is achieved in accordance with the present invention by a method and an apparatus wherein 3D data are obtained of a volume of a patient, which includes anatomy such as a selected organ, which is to be the subject of a robotically-implemented surgical procedure. The anatomy or organ of interest is then segmented from an image of the aforementioned volume that has been reconstructed from the 3D data. The segmentation can be done either manually or by a computerized pattern recognition segmentation algorithm. During the course of the robotically implemented surgical intervention, the surgeon causes one or more forces on the anatomy or organ to occur that cause a modification or displacement of the anatomy or organ (geometric change). These forces are known by being detected by the force sensors that are conventionally present in commercially available robotic manipulators. These forces are supplied to a processor that controls the display of the segmented anatomy or organ at a display screen that is viewed by the surgeon or an assistant during the procedure. The processor calculates the amount of modification or displacement of the anatomy or organ that has occurred as a result of the applied forces and as a result of the physical properties of the anatomy or organ. The processor then automatically modifies the appearance and/or position of the displayed segmented anatomy or organ on the display screen in real time during the procedure, so that the surgeon always has a current visualization of the state of the anatomy or organ as the procedure progresses. Additionally, because the organ or anatomy has been segmented, all conventional operations that can be applied to displayed, segmented anatomy can be implemented by the surgeon during the procedure, such as rotation, translation, etc. For example, if an anterior view of the anatomy or organ is being displayed, the physician can rotate the organ to obtain a posterior view, which would normally not be able to be seen in the conventional endoscopic images that are used during such procedures.

The data representing the physical properties of the anatomy or organ that is the subject of the surgical intervention, which are used in combination with the forces applied by the robotic manipulator in order to computationally determine the resulting modification or displacement of the anatomy or organ, can be obtained from an anatomical atlas. Such an atlas can be compiled for respective anatomy or organs of a general patient population, or can be more specifically matched to a patient population comparable to the patient who is undergoing the procedure. For example, an atlas can be compiled for patients of an age or medical history comparable to that of the patient, patients exhibiting the same pathological condition of the relevant anatomy or organ, etc.

The present invention also encompasses a non-transitory, computer-readable data storage medium that is encoded with programming instructions that, when executed by one or more processors in which the storage medium is loaded, or that have access to the loaded storage medium, cause any or all of the above embodiments of the method according to the invention to be implemented. The storage medium can be loaded into a processor of a central workstation that controls the overall functions performed during the course of a robotically-implemented surface procedure, or the programming instructions can be distributed appropriately among respective processors that individually have responsibility for controlling a subset of the complete suite of functions.

FIG. 1 is a flowchart showing basic steps of the method in accordance with the invention, with optional steps being shown in dashed lines.

FIG. 2 is a block diagram showing the basic components of an apparatus constructed and operating in accordance with the present invention.

As shown in the flowchart of FIG. 1 , the method in accordance with the invention begins in step 1 with the positioning of a patient on a table in a surgical venue. The patient is to undergo a robotically-implemented surgical procedure in the operating venue, while on the table.

After the patient has been placed on the table, 3D data are acquired in step 2 from a volume of the patient that includes the anatomy or the organ that is to be the subject of the robotically-manipulated surgical intervention.

In step 3 , the acquired 3D data are supplied to a processor, which implements a 3D reconstruction algorithm to generate a 3D image of the volume of the patient represented by the acquired 3D data.

In step 4 , the specific anatomy or organ that is the subject of the intervention is segmented from the overall 3D image of the volume. This can be implemented manually, such as by interaction of the surgeon with the displayed image on a screen, with the surgeon using a light pen or cursor to outline the organ or anatomy to be segmented. The segmentation alternatively can be implemented completely automatically, using known pattern recognition-based segmentation algorithms.

An option in accordance with the present invention is to provide, in step 12 , a pre-operative data set of the patient, which may be a data set representing one or more medical images of the patient that have been acquired in previous examinations of the patient. Such a pre-operative 3D data set can include any of the known techniques that are used to highlight or enhance selected anatomy or pathological conditions, such as by color coding, contrast agent enhancement, fMRI images in the case of brain surgery being implemented, diffusion-weighted images, etc.

If such a pre-operative data set is optionally provided in step 12 , this pre-operative data set is then brought into registration with the aforementioned 3D reconstructed image of the patient on the table in step 13 , and the segmentation can then be implemented in order to segment the anatomy or organ from the registered, pre-operative data set combined with the reconstructed volume image.

Following the segmentation, material properties are assigned by the processor to the segmented regions in step 5 . These material properties are known or expected properties of the segmented anatomy that are provided to the processor, such as by the processor having access to an anatomical atlas. The anatomical atlas can provide a listing of relevant material properties of many different anatomical regions or organs, and the processor then selects the appropriate set of properties from the atlas that correspond to the segmented region. As noted above, the atlas can be compiled for a general patient population, or can be more specifically directed to patients comparable to the patient on whom the surgical procedure is to be implemented. For example, the atlas may be compiled from patients of the same age group as the patient, patients exhibiting the same pathological conditions of the segmented anatomy as the patient, patients having a medical history similar to that of the patient, etc.

In parallel with, or interleaved with, the aforementioned steps in accordance with the invention, in step 6 the coordinate system of the operation device (robotic manipulator) that is to be used in the procedure is brought into registration with the coordinate system of the scanning device, with which the aforementioned 3D image of the patient on the table was acquired. This registration of these coordinate systems can be implemented in any known manner, such as by knowledge of the physical relationship of the coordinate systems that results by virtue of the physical mounting of the operation device on the patient table, or by markers attached at suitable locations on the operation device that are visible in the acquired 3D data of the patient on the patient table, in which case the operation device must also be within the field of view of the scanning device. Suitable navigation systems are also known that identify the respective coordinate systems of the operation device and the scanner, and bring those coordinate systems into registration with each other.

The interventional procedure is then started, using the operation device in order to selectively manipulate anatomy or an organ within the reconstructed volume (step 7 ). Commercially available operation devices, such as robotic manipulators, provide haptic feedback to the surgeon who is operating the device, and for this purpose contain force sensors that detect forces that are applied to the anatomy or organ by the operation device during the course of the procedure. The processor that is used by the operation device to provide the haptic feedback thus may already provide an accurate estimate of the force or forces that are applied to the anatomy or organ during the procedure, and the output of this processor can be provided to the processor that controls display of the segmented region at a display screen situated at the operation venue, which can be seen by the surgeon during the course of the procedure.

Alternatively, the outputs of these force sensors can be directly supplied to the processor, and the processor can generate its own estimate of the force or forces that have been applied to the segmented volume.

Either type of estimation takes place in step 8 .

Based on the estimated force or forces applied to the segmented volume at any given time during the procedure, and based on the material properties of the segmented regions, the processor automatically determines in step 9 , modification or displacement of the organ or anatomy that has occurred, and updates the display of the segmented volume in step 10 in order to incorporate such modification or displacement. This updated segmented volume is then visualized at the display in step 11 , and can be selectively manipulated by the surgeon in the usual manner of a segmented volume, such as by rotation or translation thereof.

The surgeon thus not only sees the state of the segmented anatomy or organ as it changes during the course of the procedure, but also can manipulate the updated (current) segmented volume so as to obtain views thereof that would not be available from a conventional endoscopic image, which can only detect the side of the anatomy or organ that is facing the endoscopic camera.

FIG. 2 is a block diagram illustrating the basic components of the apparatus according to the invention. The apparatus includes an imaging device or system 14 , such as a C-arm x-ray imaging system mounted on a robot. Such a system may be, for example, the Artis VD 11 angio-system that is commercially available from Siemens Healthcare. The system can include suitable collision monitoring components and other control modules of the type that are conventionally available for use in a surgical environment. The imaging system 14 includes a patient table, on which the patient lies during the procedure, to which a surgical robot 17 is mounted. The surgical robot is operated from a surgeon console 18 , which includes any number of control elements that are manipulated by the surgeon during the course of the procedure. The manipulations that are made by the surgeon at the console are translated to movements of the surgical robot, including the operation of tools or instruments carried by the surgical robot, such as scissors, grabbers, etc. The surgeon console provides appropriate control commands to the robot that cause the aforementioned actions to be implemented. The robot can carry an endoscopic camera having a field of view that encompasses the surgery site, so that endoscopic images of the surgery site are provided to the surgeon at the surgeon console.

The imaging system is operated by a computer at a workstation (control console) 15 to acquire the aforementioned 3D images of the patient on the table, such as CT images. The acquired 3D data are reconstructed to show an image of the acquired region, from which anatomy or an organ of interest is then segmented at the workstation 15 . The aforementioned endoscopic images can also be supplied to the workstation 15 , as are the forces detected by the force sensors that are present at the surgical robot 17 . From this applied force information, and the aforementioned material properties of the segmented regions that are known to the processor at the workstation 15 from a source 16 , the updating of the segmented regions, as described above, takes place at the workstation 15 , so that the updated segmented images incorporate changes and displacements to the segmented anatomy or organ that have occurred during the course of the intervention. The updated segmented region can be displayed at a display screen of the workstation 15 , which is visible by the surgeon from the surgeon console, or can be supplied to the display screen at the surgeon console 18 for display together with the endoscopic images. The updated segmented regions can be manipulated by the surgeon either via controls that are made available directly at the surgeon console, or that are available at the workstation. The surgeon may simultaneously be able to operate the workstation 15 , or may provide oral directions to an assistant situated at the workstation 15 in order to manipulate the updated segmented image as the surgeon directs.

Although modifications and changes may be suggested by those skilled in the art, it is the intention of the inventors to embody within the patent warranted hereon all changes and modifications as reasonably and properly come within the scope of their contribution to the art.