Abstract:
Described herein are systems, apparatus, and methods for precise placement and guidance of tools during surgery, particularly spinal surgery, using minimally invasive surgical techniques. Several minimally invasive approaches to spinal surgeries were conceived, percutaneous technique being one of them. This procedures looks to establish a skin opening as small as possible by accessing inner organs via needle-puncture of the skin. The percutaneous technique is used in conjunction with a robotic surgical system to further enhance advantages of manual percutaneous techniques by improving precision, usability and/or shortening surgery time by removal of redundant steps.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    Robotic-assisted surgical systems have been developed to improve surgical precision and enable the implementation of new surgical procedures. For example, robotic systems have been developed to sense a surgeon&#39;s hand movements and translate them to scaled-down micro-movements and filter out unintentional tremors for precise microsurgical techniques in organ transplants, reconstructions, and minimally invasive surgeries. Other robotic systems are directed to telemanipulation of surgical tools such that the surgeon does not have to be present in the operating room, thereby facilitating remote surgery. Feedback-controlled robotic systems have also been developed to provide smoother manipulation of a surgical tool during a procedure than could be achieved by an unaided surgeon. 
         [0002]    However, widespread acceptance of robotic systems by surgeons and hospitals is limited for a variety of reasons. Current systems are expensive to own and maintain. They often require extensive preoperative surgical planning prior to use, and they extend the required preparation time in the operating room. They are physically intrusive, possibly obscuring portions of a surgeon&#39;s field of view and blocking certain areas around the operating table, such that a surgeon and/or surgical assistants are relegated to one side of the operating table. Current systems may also be non-intuitive or otherwise cumbersome to use, particularly for surgeons who have developed a special skill or “feel” for performing certain maneuvers during surgery and who find that such skill cannot be implemented using the robotic system. Finally, robotic surgical systems may be vulnerable to malfunction or operator error, despite safety interlocks and power backups. 
         [0003]    Spinal surgeries often require precision drilling and placement of screws or other implements in relation to the spine, and there may be constrained access to the vertebrae during surgery that makes such maneuvers difficult. Catastrophic damage or death may result from improper drilling or maneuvering of the body during spinal surgery, due to the proximity of the spinal cord and arteries. Common spinal surgical procedures include a discectomy for removal of all or part of a disk, a foraminotomy for widening of the opening where nerve roots leave the spinal column, a laminectomy for removal of the lamina or bone spurs in the back, and spinal fusion for fusing of two vertebrae or vertebral segments together to eliminate pain caused by movement of the vertebrae. 
         [0004]    Spinal surgeries that involve screw placement require preparation of holes in bone (e.g., vertebral segments) prior to placement of the screws. Where such procedures are performed manually, in some implementations, a surgeon judges a drill trajectory for subsequent screw placement on the basis of pre-operative CT scans. Other manual methods which do not involve usage of the pre-operative CT scans, such as fluoroscopy, 3D fluoroscopy or natural landmark-based, may be used to determine the trajectory for preparing holes in bone prior to placement of the screws. In some implementations, the surgeon holds the drill in his hand while drilling, and fluoroscopic images are obtained to verify if the trajectory is correct. Some surgical techniques involve usage of different tools, such as a pedicle finder or K-wires. Such procedures rely strongly on the expertise of the surgeon, and there is significant variation in success rate among different surgeons. Screw misplacement is a common problem in such surgical procedures. 
         [0005]    Image-guided spinal surgeries involve optical tracking to aid in screw placement. However, such procedures are currently performed manually, and surgical tools can be inaccurately positioned despite virtual tracking. A surgeon is required to coordinate his real-world, manual manipulation of surgical tools using images displayed on a two dimensional screen. Such procedures can be non-intuitive and require training, since the surgeon&#39;s eye must constantly scan both the surgical site and the screen to confirm alignment. Furthermore, procedural error can result in registration inaccuracy of the image-guiding system, rendering it useless, or even misleading. 
         [0006]    Certain force feedback systems are used by surgeons in certain procedures; however such systems have a large footprint and take up valuable, limited space in the operating room. These systems also require the use of surgical tools that are specially adapted for use with the force feedback system, and the training required by surgeons to operate such systems can be significant. Moreover, surgeons may not be able to use expertise they have developed in performing spinal surgeries when adapting to use of the current force feedback systems. Such systems, while precise, may require more surgical time and more operating room preparation time to ready placement of the equipment for surgery. 
         [0007]    Traditional open surgery techniques for spinal surgeries are very invasive for the patient. They require relatively big openings which increases the risk of infections, tissue destruction and recovery time. Scar may be large and reduce patient&#39;s confront and appreciation of the procedure. Thus, there is a need for systems, apparatus, and methods that provide enhanced precision in performing surgeries such as spinal surgeries. 
       SUMMARY OF THE INVENTION 
       [0008]    Described herein are systems, apparatus, and methods for precise placement and guidance of tools during surgery, particularly spinal surgery, using minimally invasive surgical techniques. Several minimally invasive approaches to spinal surgeries were conceived, percutaneous technique being one of them. This procedures looks to establish a skin opening as small as possible by accessing inner organs via needle-puncture of the skin. The percutaneous technique is used in conjunction with a robotic surgical system to further enhance advantages of manual percutaneous techniques by improving precision, usability and/or shortening surgery time by removal of redundant steps. 
         [0009]    The system, in certain embodiments, features a portable robot arm with end effector for precise positioning of a surgical tool. Minimally invasive surgical techniques are used to obtain access to vertebrae while protecting soft tissues in the surrounding area. These techniques minimize blood loss, postoperative pain, and scaring while providing for faster recoveries. 
         [0010]    The disclosed technology, in certain embodiments, includes a method of performing minimally invasive spinal surgery with a robotic surgical system using a percutaneous technique. The method includes, in certain embodiments, detecting, by a force sensor (e.g., on a robotic arm; e.g., between a robotic arm and an end effector), movement (e.g., by a surgeon) of a surgical instrument guide attached to a robotic arm of the robotic surgical system. The surgical instrument guide, in certain embodiments, defines a trajectory comprising a location and an orientation (e.g., a 3-dimensional vector) for insertion of a medical implant (e.g., screw) in a vertebra of a patient. 
         [0011]    The method may include storing, by a processor of a computer device, a planned trajectory based on the trajectory of the surgical instrument guide at a defined time (e.g., upon receiving instruction to store the trajectory as the planned trajectory; e.g., when the surgeon is satisfied with the trajectory) (e.g., wherein the planned trajectory defines the place for an incision). In certain embodiments, after the planned trajectory is defined, the method includes detecting, by the force sensor, movement of the surgical instrument guide towards the vertebra. 
         [0012]    In certain embodiments, the method includes constraining and/or maintaining, by the processor, an orientation of the surgical instrument guide along the planned trajectory as the surgical instrument guide is moved (e.g., by a surgeon; e.g., by a surgeon physically touching a portion of the robotic arm and/or end effector) through an incision to (e.g., adjacent or near) a surface of the vertebra. 
         [0013]    In certain embodiments, the method includes maintaining, by the processor, a position of the surgical instrument guide as a surgeon passes a drill through the surgical instrument guide and drills a hole in the vertebra. In certain embodiments, the method includes constraining and/or maintaining, by the processor, an orientation of the surgical instrument guide along the planned trajectory as the surgical instrument guide is moved (e.g., by a surgeon; e.g., by a surgeon physically touching a portion of the robotic arm and/or end effector) away from the vertebra (e.g., such that a medical implant (e.g., screw) can be inserted into the hole in the vertebra). 
         [0014]    In certain embodiments, the method includes maintaining, by the processor, a position of the surgical instrument guide as a k-wire (e.g., flexible k-wire) is inserted into the hole in the vertebrae (e.g., along the planned trajectory such that the orientation of the k-wire substantially represents the planned trajectory) (e.g., thereby saving the trajectory for future retrieval (e.g., after the surgical instrument guide is removed). 
         [0015]    In certain embodiments, the disclosed technology includes an adaptive tube sized and shaped to fit in the surgical instrument guide and receive a k-wire therethrough (e.g., to guide the k-wire into the hole in the vertebra). 
         [0016]    In certain embodiments, the method includes providing, by the processor, for display on a graphical user interface, a composite image comprising a visual representation of the trajectory superimposed with a medical image of the vertebra of the patient; In certain embodiments, the method includes, after the surgical instrument guide is moved through the incision, detecting, by a force sensor, movement of the surgical instrument guide (e.g., as a surgeon adjusts (e.g., fine adjustment) the planned trajectory); and storing, by the processor, an updated planned trajectory (e.g., as the planned trajectory). 
         [0017]    In certain embodiments, the surgeon decouples a translation movement of the surgical instrument guide from a rotation movement of the surgical instrument guide. 
         [0018]    In certain embodiments, the method includes maintaining a position of the surgical instrument guide as a surgeon passes a tap through the surgical instrument guide and taps the hole in the vertebra. In certain embodiments, the method includes tapping, by a surgeon, the hole in the vertebra (e.g., by sliding a tap along the k-wire to orient the k-wire relative to the hole). 
         [0019]    In certain embodiments, the method includes placing, by the surgeon, the screw in the hole in the vertebra (e.g., wherein the hole is tapped or untapped) (e.g., using a screw driver that is slide along the k-wire; e.g., using a navigation system to guide the surgeon (e.g., without a k-wire)). In certain embodiments, the method includes the medical implant is a screw. In certain embodiments, the method includes the medical implant is a screw, and an extensor is attached to the back of the screw. 
         [0020]    In certain embodiments, the method includes inserting, by a surgeon, along the trajectory, a medical implant (e.g., a screw) into the hole in the vertebra. In certain embodiments, the method includes, before the surgical instrument guide is moved through the incision, cutting, by a surgeon, at least one of the patient&#39;s muscles and skin, thereby creating a working channel. 
         [0021]    In certain embodiments, the method includes maneuvering a first dilator to access a vertebrae of a patient through the patient&#39;s muscles and skin, wherein the dilator defines a working channel for accessing the vertebrae; and increasing the size of the working channel (e.g., using one or more dilators subsequent to the first dilator, whereby a subsequent dilator is temporarily secured in the patient tissue). 
         [0022]    In certain embodiments, the method includes removing one or more dilators prior to inserting the medical implant (e.g., screw). 
         [0023]    During minimally invasive surgical procedures, dilators may be used to create a working channel through which an operation is performed. The dilators may be a set of tubes with increasing diameters which are inserted into a small incision one at a time until the desired diameter of the working channel is achieved. The dilators may be used with a robotic surgical system (e.g., attached to the robotic arm) to perform a minimally invasive surgery. This allows the usage, in certain embodiments, of standard dilators and a robotic surgical system to provide precise guidance of surgical tools through a dilator and greater flexibility. The dilator may be held by the robot and automatically repositioned when the surgeon adjusts the trajectory along which, for example, a hole is prepared in a vertebra. Adjustment of the end effector of the robotic surgical system automatically adjusts an angle and/or position of the dilator attached to the robot with respect to the vertebrae and aligns an axis defined by the dilator with a desired trajectory during a surgical procedure without removal of the dilator from the patient tissue during the repositioning. 
         [0024]    For example, first dilator may be used to access a vertebrae of a patient through the patient&#39;s muscles and skin, thereby defining a working channel for accessing the vertebrae. One or more subsequent dilators may be slid over the first dilator. Each of the one or more subsequent dilators are configured to be positioned over the preceding dilators and increase the size of the working channel. Each dilator except the last added dilator is configured to be removed from the patient thereby leaving the last added dilator. The last added dilator is configured to be attached to an end effector of a robotic arm using a dilator fixator. A manipulator is configured to allow robotically-assisted or unassisted positioning and/or movement of the last added dilator by a user with at least four degrees of freedom to align an axis defined by the last added dilator with respect to the vertebrae. Adjustment of the manipulator automatically adjusts an angle and/or position of the attached dilator with respect to the vertebrae and aligns an axis defined by the attached dilator with a desired trajectory during a surgical procedure without removal of the attached dilator from the patient tissue during the repositioning. 
         [0025]    The system requires only minimal training by surgeons/operators, is intuitive to use, and has a small footprint with significantly reduced obstruction of the operating table. The system works with existing, standard surgical tools, does not require increased surgical time or preparatory time, and safely provides the enhanced precision achievable by robotic-assisted systems. Moreover, the system allows for a desired trajectory (e.g., for a drill guide during spinal surgery) to be set in a variety of manners based on the circumstances of the surgery. For example, some surgical procedures are planned pre-operatively with the surgeon defining the desired position of an implant using imaging technology, such as CT images (e.g., 3D CT images). The desired position of the implant may also be determined and proposed by the system. In the operating room the surgeon may be guided by the robotic system (e.g., robotic guidance of the surgical tools) to accurately execute the planning. 
         [0026]    A mobile cart houses a robot arm with an end effector that holds various standard surgical tools/implants, such as a drill or screw. Positioning such surgical tools with precision is critical. The robot arm provides more precise, stable placement of such tools than can be achieved manually, where placement is guided, yet intuitive. The mobile cart permits easy set-up and use of the system. Once stabilization is engaged, the mobile cart is secured in place on the operating room floor and cannot move. In certain embodiments, the robot cart houses the robot, robot controller, supervisor interlock system, power system, riding system, and interface to the navigation system. 
         [0027]    The disclosed technology, in certain embodiments, includes a method of performing minimally invasive spinal surgery with a robotic surgical system. The method may include: maneuvering a first dilator (defining a working channel for accessing the vertebrae) to access a vertebrae of a patient through the patient&#39;s muscles and skin; increasing the size of the working channel (e.g., using one or more dilators subsequent to the first dilator, whereby a subsequent dilator is temporarily secured in the patient tissue); attaching the first dilator or a subsequent dilator to the end effector of the robotic arm using a dilator fixator; and following attachment of the first or a subsequent dilator to the end effector, repositioning the end effector thereby automatically adjusting an angle and/or position of the attached dilator with respect to the vertebrae and aligning an axis defined by the attached dilator with a desired trajectory during a surgical procedure without removal of the attached dilator from the patient tissue during the repositioning. 
         [0028]    Increasing the size of the working channel may include maneuvering a second dilator over the first dilator, wherein the second dilator is sized and shaped to slide over the first dilator and increase the size of the working channel; and, after positioning the second dilator over the first dilator (and/or after positioning one or more subsequent dilators over the preceding dilators), removing the first dilator (and/or other previous dilators except the final added dilator) from the patient, thereby leaving the last added dilator, wherein the attached dilator is the last added dilator. In certain embodiments, the attached dilator is the dilator with largest circumference. 
         [0029]    In certain embodiment, increasing the size of the working channel includes expanding the diameter of the first dilator thereby increasing the diameter of the working channel, wherein the dilator attached to the end effector is the first dilator. 
         [0030]    The method, in certain embodiments, includes placing a surgical instrument guide inside of the attached dilator, wherein the surgical instrument guide is sized and shaped to fit at least partially inside the attached dilator along an axis defined by said dilator. The end effector may include a surgical instrument guide attached thereto, configured to hold and/or restrict movement of a surgical instrument therethrough. The surgical instrument guide may include at least one of a drill bit guide, tap guide, screwdriver guide, screw guide, awl guide, and implant guide. The surgical instrument may be at least one of a drill bit, tap, screwdriver, screw, implant, and awl, wherein the surgical instrument is configured to slide through the surgical instrument guide. The attached dilator may be configured to hold and/or restrict movement of a surgical instrument therethrough. 
         [0031]    The method, in certain embodiments, includes registering the patient, wherein registering the patient comprises identifying the transformation between the actual patient anatomy and one or more medical images; maneuvering the end effector towards the vertebrae on which the surgeon will operate; determining, by a processor of a computing device, an ideal implant trajectory; and providing, by the processor, for display on a graphical user interface, the ideal implant trajectory for review by the surgeon, wherein (i) the surgeon may adapt the ideal implant trajectory if needed using hands-on planning, and (ii) the surgeon acknowledges the ideal implant trajectory or the adapted trajectory thereby causing the acknowledged trajectory to be stored as the desired trajectory. 
         [0032]    The method may include, prior to maneuvering the attached dilator: moving a mobile cart transporting a robotic surgical system comprising a robotic arm in proximity to an operating table, wherein the robotic arm has an end effector; and stabilizing the mobile cart. 
         [0033]    The disclosed technology, in certain embodiments, includes a robotic surgical system for performing minimally invasive surgery. The system may include: a robotic arm with an end effector; a first dilator to access a vertebrae of a patient through the patient&#39;s muscles and skin, wherein the first dilator defines a working channel for accessing the vertebrae; one or more subsequent dilators sized and shaped to slide over the first dilator and/or one or more of the one or more subsequent dilators. The one or more subsequent dilators may include a last added dilator, and each of the one or more subsequent dilators are configured to be positioned over the preceding dilators and increase the size of the working channel. Each dilator except the last added dilator may be configured to be removed from the patient thereby leaving the last added dilator, and the last added dilator may be configured to be attached to the end effector of the robotic arm using a dilator fixator. 
         [0034]    The system may include a manipulator configured to allow robotically-assisted or unassisted positioning and/or movement of the end effector by a user with at least four degrees of freedom thereby automatically adjusting an angle and/or position of the last added dilator with respect to the vertebrae and aligning an axis defined by the last added dilator with a desired trajectory during a surgical procedure without removal of the last added dilator from the patient tissue during the repositioning. 
         [0035]    Each one or more subsequent dilators may have a circumference larger than the circumference of the first dilator, and the one or more subsequent dilators increase the size of the working channel as each subsequent dilator is added. 
         [0036]    The system may include a surgical instrument guide configured to be placed inside of the attached dilator, wherein the surgical instrument guide is sized and shaped to fit at least partially inside the attached dilator along an axis defined by the dilator. The end effector may include the surgical instrument guide attached thereto, configured to hold and/or restrict movement of a surgical instrument therethrough. The surgical instrument guide is may be a drill bit guide, tap guide, screwdriver guide, screw guide, awl guide, and implant guide. The surgical instrument may be a drill bit, tap, screwdriver, screw, implant, and awl, wherein the surgical instrument is configured to slide through the surgical instrument guide. 
         [0037]    The attached dilator may be the dilator with largest circumference. The attached dilator may be configured to hold and/or restrict movement of a surgical instrument therethrough. 
         [0038]    In certain embodiments, the system includes: a processor; and a memory, the memory storing instructions that, when executed by the processor, cause the processor to: store a transformation between the actual patient anatomy and one or more medical images; determine an ideal implant trajectory; and provide, for display on a graphical user interface, the ideal implant trajectory for review by the surgeon, wherein (i) the surgeon may adapt the ideal implant trajectory if needed using hands-on planning, and (ii) the surgeon acknowledges the ideal implant trajectory or the adapted trajectory thereby causing the acknowledged trajectory to be stored as the desired trajectory. 
         [0039]    The disclosed technology, in certain embodiments, may include a robotic surgical system for performing minimally invasive surgery with a robotic arm with an end effector; a dilator to access a vertebrae of a patient through the patient&#39;s muscles and skin; and a manipulator configured to allow robotically-assisted or unassisted positioning and/or movement of the end effector by a user with at least four degrees of freedom thereby automatically adjusting an angle and/or position of the dilator with respect to the vertebrae and aligning an axis defined by the dilator with a desired trajectory during a surgical procedure without removal of the dilator from the patient tissue during the repositioning. The dilator may define a working channel for accessing the vertebrae. The dilator may be configured to be expanded to increase the size of the working channel and be attached to an end effector of a robotic arm using a dilator fixator. 
         [0040]    The system may include a surgical instrument guide configured to be placed inside of the dilator. The surgical instrument guide is sized and shaped to fit at least partially inside the dilator along an axis defined by the dilator. The end effector may include the surgical instrument guide attached thereto, configured to hold and/or restrict movement of a surgical instrument therethrough. 
         [0041]    The robotic arm may be configured to be maneuvered to a desired position to align an axis defined by the surgical instrument guide at a desired trajectory in relation to the vertebrae. The dilator connected to the end effector of the robotic arm may be automatically positioned as the robotic arm is maneuvered to adjust to the desired trajectory. The dilator is configured to hold and/or restrict movement of a surgical instrument therethrough. 
         [0042]    The system may include a processor; and a memory, the memory storing instructions that, when executed by the processor, cause the processor to: store a transformation between the actual patient anatomy and one or more medical images; determine an ideal implant trajectory; and provide, for display on a graphical user interface, the ideal implant trajectory for review by the surgeon, wherein (i) the surgeon may adapt the ideal implant trajectory if needed using hands-on planning, and (ii) the surgeon acknowledges the ideal implant trajectory or the adapted trajectory thereby causing the acknowledged trajectory to be stored as the desired trajectory. 
         [0043]    In one aspect, the disclosed technology includes a robotic surgical system including a processor programmed to: detect, via a force sensor (e.g., on a robotic arm; e.g., between a robotic arm and an end effector), movement (e.g., by a surgeon) of a surgical instrument guide attached to a robotic arm of the robotic surgical system, wherein the surgical instrument guide defines a trajectory comprising a location and an orientation (e.g., a 3-dimensional vector) for insertion of a medical implant (e.g., screw) in a vertebra of a patient; store, a planned trajectory based on the trajectory of the surgical instrument guide at a defined time (e.g., upon receiving instruction to store the trajectory as the planned trajectory; e.g., when the surgeon is satisfied with the trajectory) (e.g., wherein the planned trajectory defines the place for an incision); after the planned trajectory is defined, detect, via the force sensor, movement of the surgical instrument guide towards the vertebra; constrain and/or maintain an orientation of the surgical instrument guide along the planned trajectory as the surgical instrument guide is moved (e.g., by a surgeon; e.g., by a surgeon physically touching a portion of the robotic arm and/or end effector) through an incision to (e.g., adjacent or near) a surface of the vertebra; maintain a position of the surgical instrument guide as a surgeon passes a drill through the surgical instrument guide and drills a hole in the vertebra; and constrain and/or maintain an orientation of the surgical instrument guide along the planned trajectory as the surgical instrument guide is moved (e.g., by a surgeon; e.g., by a surgeon physically touching a portion of the robotic arm and/or end effector) away from the vertebra (e.g., such that a medical implant (e.g., screw) can be inserted into the hole in the vertebra). 
         [0044]    In certain embodiments, the processor is programmed to: maintain a position of the surgical instrument guide as a k-wire (e.g., flexible k-wire) is inserted into the hole in the vertebrae (e.g., along the planned trajectory such that the orientation of the k-wire substantially represents the planned trajectory) (e.g., thereby saving the trajectory for future retrieval (e.g., after the surgical instrument guide is removed). 
         [0045]    In certain embodiments, the system includes an adaptive tube sized and shaped to fit in the surgical instrument guide and receive a k-wire therethrough (e.g., to guide the k-wire into the hole in the vertebra). 
         [0046]    In certain embodiments, the system includes a graphical user interface for display of a composite image comprising a visual representation of the trajectory superimposed with a medical image of the vertebra of the patient. 
         [0047]    In certain embodiments, the processor is programmed to: after the surgical instrument guide is moved through the incision, detect, via a force sensor, movement of the surgical instrument guide (e.g., as a surgeon adjusts (e.g., fine adjustment) the planned trajectory); and store an updated planned trajectory (e.g., as the planned trajectory). 
         [0048]    In certain embodiments, the processor is programmed to permit a translation movement of the surgical instrument guide (e.g., by a surgeon) decoupled from a rotation movement of the surgical instrument guide. 
         [0049]    In certain embodiments, the processor is programmed to: maintain a position of the surgical instrument guide as a surgeon passes a tap through the surgical instrument guide and taps the hole in the vertebra. 
         [0050]    In certain embodiments, the system includes one or more members selected from the group consisting of the robotic arm, the force sensor, the end effector, and the surgical instrument guide. 
         [0051]    In certain embodiments, the incision is from 1 mm to 25 mm, 5 mm to 20 mm, or 10 mm to 15 mm. 
         [0052]    In another aspect, the disclosed technology includes a method of operating a robotic surgical system, the method including: detecting, by a force sensor (e.g., on a robotic arm; e.g., between a robotic arm and an end effector), movement (e.g., by a surgeon) of a surgical instrument guide attached to a robotic arm of the robotic surgical system, wherein the surgical instrument guide defines a trajectory comprising a location and an orientation (e.g., a 3-dimensional vector) for insertion of a medical implant (e.g., screw) in a vertebra of a patient; storing, by a processor of a computer device, a planned trajectory based on the trajectory of the surgical instrument guide at a defined time (e.g., upon receiving instruction to store the trajectory as the planned trajectory; e.g., when the surgeon is satisfied with the trajectory) (e.g., wherein the planned trajectory defines the place for an incision); after the planned trajectory is defined, detecting, by the force sensor, movement of the surgical instrument guide towards the vertebra; constraining and/or maintaining, by the processor, an orientation of the surgical instrument guide along the planned trajectory as the surgical instrument guide is moved (e.g., by a surgeon; e.g., by a surgeon physically touching a portion of the robotic arm and/or end effector) through an incision to (e.g., adjacent or near) a surface of the vertebra; maintaining, by the processor, a position of the surgical instrument guide as a surgeon passes a drill through the surgical instrument guide and drills a hole in the vertebra; and constraining and/or maintaining, by the processor, an orientation of the surgical instrument guide along the planned trajectory as the surgical instrument guide is moved (e.g., by a surgeon; e.g., by a surgeon physically touching a portion of the robotic arm and/or end effector) away from the vertebra (e.g., such that a medical implant (e.g., screw) can be inserted into the hole in the vertebra). 
         [0053]    In certain embodiments, the method includes maintaining, by the processor, a position of the surgical instrument guide as a k-wire (e.g., flexible k-wire) is inserted into the hole in the vertebrae (e.g., along the planned trajectory such that the orientation of the k-wire substantially represents the planned trajectory) (e.g., thereby saving the trajectory for future retrieval (e.g., after the surgical instrument guide is removed). 
         [0054]    In certain embodiments, the system includes an adaptive tube sized and shaped to fit in the surgical instrument guide and receive a k-wire therethrough (e.g., to guide the k-wire into the hole in the vertebra). 
         [0055]    In certain embodiments, the method includes providing, by the processor, for display on a graphical user interface, a composite image comprising a visual representation of the trajectory superimposed with a medical image of the vertebra of the patient. 
         [0056]    In certain embodiments, the method includes, after the surgical instrument guide is moved through the incision, detecting, by a force sensor, movement of the surgical instrument guide (e.g., as a surgeon adjusts (e.g., fine adjustment) the planned trajectory); and storing, by the processor, an updated planned trajectory (e.g., as the planned trajectory). 
         [0057]    In certain embodiments, the surgeon decouples a translation movement of the surgical instrument guide from a rotation movement of the surgical instrument guide. 
         [0058]    In certain embodiments, the method includes maintaining a position of the surgical instrument guide as a surgeon passes a tap through the surgical instrument guide and taps the hole in the vertebra. 
         [0059]    In certain embodiments, the method includes tapping, by a surgeon, the hole in the vertebra (e.g., by sliding a tap along the k-wire to orient the k-wire relative to the hole). 
         [0060]    In certain embodiments, the method includes placing, by the surgeon, the screw in the hole in the vertebra (e.g., wherein the hole is tapped or untapped) (e.g., using a screw driver that is slid along the k-wire; e.g., using a navigation system to guide the surgeon (e.g., without a k-wire)). 
         [0061]    In certain embodiments, the medical implant comprises a screw. 
         [0062]    In certain embodiments, the medical implant comprises a screw, and an extensor is attached to the back of the screw. 
         [0063]    In certain embodiments, the method includes inserting, by a surgeon, along the trajectory, a medical implant (e.g., a screw) into the hole in the vertebra. 
         [0064]    In certain embodiments, the method includes, before the surgical instrument guide is moved through the incision, cutting, by a surgeon, at least one of the patient&#39;s muscles and skin, thereby creating a working channel. 
         [0065]    In certain embodiments, the method includes maneuvering a first dilator to access a vertebra of a patient through the patient&#39;s muscles and skin, wherein the dilator defines a working channel for accessing the vertebra; and increasing the size of the working channel (e.g., using one or more dilators subsequent to the first dilator, whereby a subsequent dilator is temporarily secured in the patient tissue). 
         [0066]    In certain embodiments, the method includes removing one or more dilators prior to inserting the medical implant (e.g., screw). 
         [0067]    In certain embodiments, the incision is from 1 mm to 25 mm, 5 mm to 20 mm, or 10 mm to 15 mm. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0068]    The foregoing and other objects, aspects, features, and advantages of the present disclosure will become more apparent and better understood by referring to the following description taken in conjunction with the accompanying drawings, in which: 
           [0069]      FIG. 1  is a diagram of an operating room in which a mobile cart housing a robotic system for a robotic-assisted spinal surgical procedure is positioned, in accordance with various embodiments of the disclosed technology; 
           [0070]      FIGS. 2A-B  are illustrations of an example set of dilators used for performing a minimally invasive surgical procedure; 
           [0071]      FIG. 3  is an illustration of an example robotic surgical system using a dilator; 
           [0072]      FIG. 4  is an illustration of an example robotic surgical system for performing minimally invasive surgery using a guided dilator; 
           [0073]      FIG. 5  is a flowchart of an example method of performing minimally invasive spinal surgery with a robotic surgical system; 
           [0074]      FIG. 6  is a flowchart of an example method for performing minimally invasive surgery using minimally invasive surgical techniques; 
           [0075]      FIG. 7  is a flowchart of an example method for performing minimally invasive surgery using minimally invasive surgical techniques; 
           [0076]      FIG. 8  is an illustration of an example dilator fixation for attaching a dilator to a robotic arm; 
           [0077]      FIGS. 9A-B  illustrate a block diagram of an example method of performing minimally invasive spinal surgery with a robotic surgical system; 
           [0078]      FIG. 10  is an intraoperative medical image showing a vertebrae before placing screws therein; 
           [0079]      FIG. 11  is a postoperative medical image showing vertebrae with screws in place; 
           [0080]      FIG. 12  is a volumetric medical image showing small skin incisions after percutaneous screw placement; 
           [0081]      FIG. 13  is a volumetric medical image showing screws placed in the vertebrae; 
           [0082]      FIG. 14  illustrates a block diagram of an exemplary cloud computing environment; and 
           [0083]      FIG. 15  is a block diagram of a computing device and a mobile computing device. 
       
    
    
       [0084]    The features and advantages of the present disclosure will become more apparent from the detailed description set forth below when taken in conjunction with the drawings, in which like reference characters identify corresponding elements throughout. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0085]      FIG. 1  illustrates an example surgical robotic system in an operating room  100 . In some implementations, one or more surgeons, surgical assistants, surgical technologists and/or other technicians, ( 106   a - c ) perform an operation on a patient  104  using a robotic-assisted surgical system. In certain embodiments, the operation may comprise insertion of one or more medical implants (e.g., screws) into the spine of a patient. The robotic system comprises an end effector which can be used to precisely define a trajectory (e.g., intraoperatively. For example, a surgeon may grab the end effector (e.g., a surgical instrument tube or a handle) and move the end effector such a desired trajectory is defined by the end effector (e.g., surgical instrument). Specifically, in the context of a surgical instrument guide, the surgeon may move the guide such that the trajectory along the length of the guide (e.g., the center of the guide) is in the desired position. 
         [0086]    The trajectory can be displayed on a computer screen, thereby providing a surgeon with the ability to precisely orient the trajectory. The robotic surgical system assists the surgeon in precisely perform various steps in the surgery, such as drilling, tapping, dilating, and insertion of the screw (e.g., by maintaining the position of a surgical instrument guide relative to a vertebra—in some implementations, the guide moves to track movement of the vertebra). 
         [0087]    Moreover, when desired (e.g., once the desired trajectory has been identified), the robot is prevented from moving in any direction but along the trajectory. As a surgeon maneuvers the surgical instrument guide, the control unit of the robotic surgical system restricts the movement of the surgical instrument guide to the defined trajectory. The surgeon can maneuver the surgical instrument guide closely to the patient&#39;s skin and pause the movement. The surgeon then cuts the muscle and skin tissue of the patient. The surgeon may entire a fine tuning mode such that very fine, precise adjustments can be made as the surgical instrument guide approaches the vertebra or when the guide is at/near the vertebra. Thus the surgeon can progress the surgical instrument guide through the muscle and skin of the patient along the new trajectory, thereby increasing the precision of the insertion. 
         [0088]    One or more dilators may be used with the robotic surgical system to perform a minimally invasive surgery. The dilators may be used to provide a working channel through which the operation is performed. Standard dilators may be used with a robotic surgical system to provide precise guidance of surgical tools. A dilator may be held by the robot and automatically repositioned when the surgeon adjusts the trajectory for performing the surgery. The dilator itself may be used as a surgical instrument guide along with dilator adaptors that adjust the diameter of a portion of the dilator to allow for different sized tools to be guided by the dilator. Surgical instrument guides may also be held by the robotic arm such that tools are guided by a surgical instrument guide through the dilator to perform a medical procedure. Throughout this specification, the terms surgical instrument guide and dilator may be used interchangeably when related to the function of guiding or constraining the robotic-assisted surgical system or a surgical instrument. 
         [0089]    For example, first dilator may be used to access a vertebrae of a patient through the patient&#39;s muscles and skin. Subsequent dilators are configured to be positioned over the preceding dilators and increase the size of the working channel. Each dilator except the last added dilator is configured to be removed from the patient thereby leaving the last added dilator. The last added dilator is configured to be attached to an end effector of a robotic arm using a dilator fixator. In another example, the dilator inserted into the patient may be designed to expand thereby increasing the diameter of the working channel without adding additional dilators. 
         [0090]    A manipulator is configured to allow robotically-assisted or unassisted positioning and/or movement of the surgical instrument guide by a user with at least four degrees of freedom to align an axis defined by the surgical instrument guide with respect to the vertebrae. Adjustment of the manipulator automatically adjusts an angle and/or position of the attached surgical instrument guide with respect to the vertebrae and aligns an axis defined by the attached surgical instrument guide with a desired trajectory during a surgical procedure without removal of the attached surgical instrument guide from the patient tissue during the repositioning. 
         [0091]    In some implementations, the surgical robotic system includes a surgical robot  102  on a mobile cart. The surgical robot  102  may be positioned in proximity to an operating table  112  without being attached to the operating table, thereby providing maximum operating area and mobility to surgeons around the operating table and reducing clutter on the operating table. In alternative embodiments, the surgical robot (or cart) is securable to the operating table. In certain embodiments, both the operating table and the cart are secured to a common base to prevent any movement of the cart or table in relation to each other, even in the event of an earth tremor. 
         [0092]    In some implementations, the footprint of the mobile cart is small (for example, no greater than 682 millimeters by 770 millimeters), thereby permitting improved access by a surgeon of both sides of an operating table at which the mobile cart is positioned during an operation. 
         [0093]    The mobile cart may permit a user (operator)  106   a , such as a technician, nurse, surgeon, or any other medical personnel in the operating room, to move the surgical robot  102  to different locations before, during, and/or after a surgical procedure. The mobile cart enables the surgical robot  102  to be easily transported into and out of the operating room  100 . For example, a user  106   a  may move the surgical robot into the operating room from a storage location. In some implementations, the mobile cart may include wheels, a track system, such as a continuous track propulsion system, or other similar mobility systems for translocation of the cart. The mobile cart may include an attached or embedded handle for locomotion of the mobile cart by an operator. 
         [0094]    In some implementations, the wheels include a locking mechanism that prevents the cart from moving. The stabilizing, braking, and/or locking mechanism may be activated when the machine is turned on. In some implementations, the mobile cart includes multiple stabilizing, braking, and/or locking mechanisms. In some implementations, the stabilizing mechanism is electro-mechanical with electronic activation. The stabilizing, braking, and/or locking mechanism(s) may be entirely mechanical. The stabilizing, braking, and/or locking mechanism(s) may be electronically activated and deactivated. 
         [0095]    In some implementations, the surgical robot  102  includes a robotic arm mounted on a mobile cart. An actuator may move the robotic arm. The robotic arm may include a force control end-effector configured to hold a surgical tool. The robot may be configured to control and/or allow positioning and/or movement of the end-effector with at least four degrees of freedom (e.g., six degrees of freedom, three translations and three rotations). 
         [0096]    In some implementations, the robotic arm is configured to releasably hold a surgical tool, allowing the surgical tool to be removed and replaced with a second surgical tool. The system may allow the surgical tools to be swapped without re-registration, or with automatic or semi-automatic re-registration of the position of the end-effector. Registration spatially aligns the robot, patient (e.g., spine) and the desired trajectory. A marker may be coupled or associated with a vertebrae or other bone to assist with the registration process. The location of the marker is determined by the system. The system stores this position. The position of the vertebrae is thus known. The position of other bones may also be determined with reference to the marker. Once the registration is complete, tracking and/or immobilization ensure that the registration (e.g., spatial orientation) is maintained. Immobilization typically fixes the patient or bone (e.g., spine) with respect to the robot. In contrast, tracking system tracks the position of the patient or the bone (e.g., by tracking the movement of the marker or position of the marker relative to the robot) as described in relation to  FIGS. 1 and 3 . 
         [0097]    In some implementations, the surgical robot  102  includes a robotic arm comprising joints allowing the arm to be automatically positioned upon user command into various different predetermined configurations convenient for various preparatory, readying, and storage procedures. For example, the surgical robot  102  may be arranged in a standby configuration. In a standby configuration, the robotic arm of surgical robot  102  may be arranged in a compacted standby configuration that, for example, facilitates easy and compact storage of surgical robot  102  when it is not in use. Other configurations may include a drape configuration in which the robot arm is extended to facilitate placement of a sterile surgical drape over the robot and cart, and a preparation configuration in which the robot arm is positioned prior to movement to the operating table whereupon more precise movement of the robot arm will be performed for alignment of the trajectory of the end effector (surgical tool holder). 
         [0098]    In some implementations, the surgical system includes a surgical robot  102 , a tracking detector  108  that captures the position of the patient and different components of the surgical robot  102 , and a display screen  110  that displays, for example, real time patient data and/or real time surgical robot trajectories. 
         [0099]    In some implementations, when the surgical robot  102  is powered on, robot  102  switches from the standby configuration to another configuration, e.g., a preparation configuration. In some implementations, preset positions of the robotic arm and the arrangement of each moveable portion of the robotic arm of surgical robot  102  may be stored in a memory of the surgical system. 
         [0100]    In some implementations, the mobile cart includes a power source for powering the robotic system, including, for example, the actuator. The power source may include a battery and/or a battery backup. In some implementations, the mobile cart is charged and/or powered by an electrical socket in the operating room. The mobile cart may be capable of being powered by a battery on the cart and/or via an electrical outlet. In some implementations, power is provided via an electrical outlet during the surgical procedure. A battery may be used to provide power to the system when the system is being moved or in case of a power cut. 
         [0101]    In some implementations, different elements of the surgical system work in tandem by communicating with each other wirelessly. In some implementations, a tracking detector  108  monitors the location of patient  104  and the surgical robot  102 . The tracking detector may be a camera, a video camera, an infrared detector, field generator and sensors for electro-magnetic tracking or any other motion detecting apparatus. In some implementation, based on the patient and robot position, the display screen displays a projected trajectory and/or a proposed trajectory for the robotic arm of robot  102  from its current location to a patient operation site. By continuously monitoring the patient and robotic arm positions, using tracking detector  108 , the surgical system can calculate updated trajectories and visually display these trajectories on display screen  110  to inform and guide surgeons and/or technicians in the operating room using the surgical robot. In addition, in certain embodiments, the surgical robot  102  may also change its position and automatically position itself based on trajectories calculated from the real time patient and robotic arm positions captured using the tracking detector  108 . For instance, the trajectory of the end-effector can be automatically adjusted in real time to account for movement of the vertebrae or other part of the patient during the surgical procedure. 
         [0102]    For safety reasons, the mobile cart is provided with a stabilization system that may be used during a surgical procedure performed with a surgical robot. The stabilization mechanism increases the global stiffness of the mobile cart relative to the floor in order to ensure the accuracy of the surgical procedure. 
         [0103]      FIGS. 2A-B  are illustrations of an example set of dilators  202  used for performing a minimally invasive surgical procedure. Dilators  202  may be used to achieve a working channel for surgical instruments. The dilators may be inserted manually by a surgeon one by one until the surgeon obtains the required diameter of the working channel. For example, a first dilator  202   a  may be inserted at the access point. The first dilator  202  may be a hollow tube-like device (similar to the other dilators  202   b - d ) or it may be a solid tube-like device for marking the access point. The second dilator  202   b  maybe added over the first dilator  202   a . Similarly, the third dilator  202   c  may be added over the second dilator  202   b  to further increase the size of the working channel. Each dilator added after the first dilator  202   a  increases the size of the working channel. In this example, the fourth dilator  202   d  is added over the third dilator  202   c . In some implementations, dilators may be removed after the next dilator is added. For example, the second dilator  202   b  may be removed after the third dilator  202   c  is added. In some implementations, dilators may be removed after the last dilator is added. For example, previously added dilators may be removed after the last dilator  202   d  is added, thereby leaving a working channel the diameter of the forth dilator  202   d.    
         [0104]    The dilators may be used with a robotic surgical system, for example, as shown in  FIG. 3 .  FIG. 3  is an illustration of an example robotic surgical system  300  using a dilator  314 . The surgeon may manually obtain access to the vertebrae  302  through the skin and muscles. After applying the dilators as described in relation to  FIGS. 2A-B , the internal dilators may be removed, leaving the largest one  314 . The robot  306  may be moved closer to the patient and attached to the dilator  314  using the dilator fixation  304 . In some implementations, a tool guide  310  held by a tool holder  312  fits inside the dilator  314 . The tool guide  310  may be used to guide a surgical instrument  308  to access the vertebrae  302  via the working channel formed by the dilator  314 . For example, the tool guide  310  may be used to prepare a hole in vertebrae of a patient. The tool holder  312  may be attached to the may be attached to the robot  306  via a tool holder attachment  316 . In some implementations, the dilator  314  itself acts as a tool guide. 
         [0105]    In some implementations, standard dilators may be used with the robotic surgical system to provide a precise solution to guide surgical tools. For example, in contrast to surgeries using passive arms to hold the dilator, the dilator may be held by the robotic surgical system and the dilator may be automatically repositioned in response to the surgeon changing the trajectory  318 . 
         [0106]    A manipulator of the robotic surgical system is configured to allow robotically-assisted or unassisted positioning and/or movement of the dilator attached to the end effector (e.g., the last added dilator) by a user with at least four degrees of freedom to align an axis defined by the dilator attached to the end effector with respect to the vertebrae. The robotic arm is configured to be maneuvered to a desired position to align an axis defined by the surgical instrument guide at a desired trajectory in relation to the vertebrae. The dilator connected to the end effector of the robotic arm is automatically positioned as the robotic arm is maneuvered to adjust to the desired trajectory. Adjustment of the manipulator automatically adjusts an angle and/or position of the attached dilator with respect to the vertebrae and aligns an axis defined by the attached dilator with a desired trajectory during a surgical procedure without removal of the attached dilator from the patient tissue during the repositioning. 
         [0107]      FIG. 4  is an illustration of an example robotic surgical system for performing a minimally invasive surgery using a guided dilator. The surgeon may manually obtain access to the vertebrae  402  through the skin and muscles. After applying the dilators as described in relation to  FIGS. 2A-B , the internal dilators may be removed, leaving the largest one  408 . The robot  406  may be moved closer to the patient and attached to the dilator  408  using the dilator fixation  404 . The dilator  408  is designed to guide a surgical tool  412 . A dilator adapter  410  may be used to allow different size tools to be used with the dilator  408 . 
         [0108]    In some implementations, standard dilators may be used with the robotic surgical system to provide a precise solution to guide surgical tools. For example, in contrast to surgeries using passive arms to hold the dilator, the dilator may be held by the robotic surgical system and the dilator may be automatically repositioned in response to the surgeon changing the trajectory  414 . 
         [0109]      FIG. 5  is a flowchart of an example method  500  of performing minimally invasive spinal surgery with a robotic surgical system. In some implementations, the method may include positioning a mobile cart ( 502 ) transporting a robotic surgical system. The robotic surgical system may include a robotic arm in proximity to an operating table. The robotic arm may have an end effector. After positioning the mobile cart, the mobile cart may be stabilized ( 504 ). 
         [0110]    The method  500  may include maneuvering a dilator to access a vertebrae of a patient through the patient&#39;s muscles and skin ( 506 ). The dilator may define a working channel for accessing the vertebrae. Additional dilators may be placed over earlier placed dilator(s) ( 508 ) to increase the size of the working channel. All dilators except the last added dilator may be removed ( 510 ) thereby leaving a working channel of a desired diameter for the surgery. 
         [0111]    For example, a second dilator may be maneuvered to slide over the dilator. The second dilator may be sized and shaped to slide over the dilator and increase the size of the working channel. After positioning the second dilator over the dilator (and/or after positioning one or more subsequent dilators over the preceding dilators), the dilator (and/or other dilators except the final added dilator) may be removed from the patient, thereby leaving the last added dilator. 
         [0112]    The method  500  may include attaching a dilator to the end effector of the robotic arm using a dilator fixator ( 512 ). In some implementations, the dilator attached (or to be attached) to the end effector is the dilator with largest circumference. Following attachment of the dilator to the end effector, the end effector may be repositioned to adjust the angle and/or position of the attached dilator with respect to the vertebrae ( 514 ). The robotic arm may be maneuvered to a desired position to align an axis defined by the surgical instrument guide at a desired trajectory in relation to the vertebrae. This causes the dilator connected to the end effector of the robotic arm to be automatically positioned as the robotic arm is maneuvered to adjust to the desired trajectory. 
         [0113]    In some implementations, a surgical instrument guide is placed inside of the dilator attached (or to be attached) to the end effector. The surgical instrument guide (e.g., drill bit guide, tap guide, screwdriver guide, screw guide, awl guide, and implant guide) is sized and shaped to fit at least partially inside the dilator along an axis defined by the dilator and is configured to hold and/or restrict movement of a surgical instrument (e.g., drill bit, pedicle finder, screw-based implant, awl, surface-pointing device, screw based implant, screw driver, tap, implants, implants with extenders, or other similar instruments) therethrough. The surgical instrument may be, for example, a tap such as the StealthStation® CR Horizon Legacy Taps from Medtronic, Inc. of Minneapolis, Minn. or a universal surgical tools system (e.g., Medtronic&#39;s NavLock system). In some implementations, the dilator itself is used as a surgical instrument guide. The dilator may be configured to hold and/or restrict movement of a surgical instrument. Dilator adapters may be used to allow different size instruments to be guided by the dilator. 
         [0114]      FIG. 6  is a flowchart of an example method  600  for performing minimally invasive surgery. In some implementations, the method may include positioning a mobile cart ( 602 ) transporting a robotic surgical system. The robotic surgical system may include a robotic arm in proximity to an operating table. The robotic arm may have an end effector. After positioning the mobile cart, the mobile cart may be stabilized ( 604 ). 
         [0115]    The method  600  may include maneuvering a dilator to access a vertebrae of a patient through the patient&#39;s muscles and skin ( 606 ). The dilator may define a working channel for accessing the vertebrae. The diameter of the working channel of the dilator may be expanded ( 608 ). For example, the dilator may be configured such that the diameter of the dilator may be increased. Thus, the size of the working channel may be increased without the use of multiple dilators. 
         [0116]    The method  600  may include attaching the dilator to the end effector of the robotic arm using a dilator fixator ( 610 ). Following attachment of the dilator to the end effector, the end effector may be repositioned to adjust the angle and/or position of the attached dilator with respect to the vertebrae ( 612 ). 
         [0117]      FIG. 7  is a flowchart of an example method  700  for performing minimally invasive surgery using minimally invasive surgical techniques. In some implementations, the method may include positioning a mobile cart ( 702 ) transporting a robotic surgical system. The robotic surgical system may include a robotic arm in proximity to an operating table. The robotic arm may have an end effector. After positioning the mobile cart, the mobile cart may be stabilized ( 704 ). 
         [0118]    The method  700  may include registering the patient ( 706 ). Registering the patient may include identifying the transformation between the actual patient anatomy and one or more medical images. Registering the patient may include identifying a correlation between the surgical anatomy of the patient in the “real world” and a medical image (e.g., an image acquisition during surgery). Registration may also be accomplished using co-registration (e.g., former studies). The robotic arm may be maneuvered towards the vertebrae on which the surgeon will operate ( 708 ). In some implementations, the robotic surgical system will recognize the vertebra on which the surgeon wishes to operate as the robotic arm is maneuvered towards the vertebra. A processor of a computing device may determine an ideal implant trajectory ( 710 ). The system allows for a desired trajectory (e.g., for a drill guide during spinal surgery) to be set in a variety of manners based on the circumstances of the surgery. For example, some surgical procedures are planned pre-operatively with the surgeon defining the desired position of an implant using imaging technology, such as CT images (e.g., 3D CT images). The desired position of the implant may also be determined and proposed by the system. In the operating room the surgeon may be guided by the robotic system (e.g., robotic guidance of the surgical tools) to accurately execute the planning. 
         [0119]    The ideal implant trajectory may be displayed on a graphical user interface for review by the surgeon ( 712 ). The surgeon may adapt the ideal implant trajectory if needed using hands-on planning. The surgeon acknowledges the ideal implant trajectory or the adapted trajectory thereby causing the acknowledged trajectory to be stored as the desired trajectory. 
         [0120]    The method  700  may include maneuvering a dilator to access a vertebrae of a patient through the patient&#39;s muscles and skin ( 714 ). The dilator may define a working channel for accessing the vertebrae. The diameter of the working channel may be expanded ( 716 ) using the techniques as described in relation to  FIGS. 5 and 6 . The method  700  may include attaching the dilator to the end effector of the robotic arm using a dilator fixator ( 718 ). Following attachment of the dilator to the end effector, the end effector may be repositioned to adjust the angle and/or position of the attached dilator with respect to the vertebrae ( 720 ). 
         [0121]    Having described various embodiments of the disclose technology, it will now become apparent to one of skill in the art that other embodiments incorporating the concepts may be used. It is felt, therefore, that these embodiments should not be limited to the disclosed embodiments, but rather should be limited only by the spirit and scope of the following claims. 
         [0122]      FIG. 8  is an illustration of an example dilator fixation  802  for attaching a dilator  804  to a robotic arm  806 . The dilator fixation  802  may be mechanically coupled to the robotic arm  806  such that the dilator fixation is rigidly coupled to the robotic arm  806 . For example, the dilator fixation  802  maybe bolted to the robotic arm  806  such that the dilator fixation  802  will not move relative to the robotic arm  806  thereby allowing the robot to always knows the position of the dilator fixation  802 . The dilator fixation  802  may provide a quick-release mechanism to rigidly secure the dilator or surgical instrument guide  804  to the robotic arm  806 . In some implementations, the dilator or surgical instrument guide  804  and dilator fixation  802  are formed as one piece and attached to the robotic arm  806  via a bolt, screw, or quick-release mechanism. The attachment system may be designed such that the dilator or surgical instrument guide  804  may be removed quickly and easily (e.g., toollessly). 
         [0123]      FIGS. 9A-B  are a flowchart of an example method for performing minimally invasive spinal surgery with a robotic surgical system. The robotic system is prepared and brought to the operating table in accordance with the methods of the present disclosure ( 902 ). The patient is prepared for the surgery ( 904 ). The surgeon brings the surgical instrument guide to the region of interest above the anatomy that will be operated on ( 906 ). Once in position and before incision, the surgeon plans a trajectory ( 908 ). The trajectory is set by maneuvering the surgical instrument guide by the surgeon. The surgeon, in certain embodiments, may physically grab the surgical instrument guide or a handle on the end effector and move the surgical instrument guide until it is aligned with the desired trajectory (e.g., as determined by the surgeon). The robot can control the rate at which the surgeon moves the surgical instrument guide to assist the surgeon in precise movements, however, in certain embodiments, the surgeon may freely move the surgical instrument guide to align it with the desired trajectory. 
         [0124]    In some implementations, the surgeon observes the current trajectory on a navigation screen. In certain embodiments, a composite image comprising a visual representation of the trajectory superimposed with a medical image of the patient&#39;s vertebrae is displayed on the navigation screen. 
         [0125]    After setting a trajectory the surgeon cuts through the patient&#39;s muscle and skin thereby exposing the vertebrae ( 910 ). In some embodiments, once a trajectory has been set, the motion of the surgical instrument guide is constrained to the trajectory. 
         [0126]    The surgical instrument guide is moved to the surface of the vertebrae along the trajectory. At this point, the surgeon may readjust the trajectory (e.g., fine tune the trajectory) right at the surface of the vertebrae ( 912 ). In some embodiments, the surgeon decouples translation movement (for finding the entry point) from rotation movement (i.e., around the tip of the surgical instrument guide or other tool defining trajectory direction). The surgeon then drills, through the surgical instrument guide, a hole into the vertebrae of the patient ( 914 ) 
         [0127]    The surgeon places a k-wire into the hole ( 916 ). In certain embodiments, the k-wire (e.g., a flexible k-wire), due to sticking out of and being constrained by the previously drilled hole, provides a physical representation of the trajectory. This allows the surgeon to physically preserve the trajectory for future retrieval. In some embodiments, the surgeon removes a portion of the surgical instrument guide (e.g., an outer or inner tube of the surgical instrument guide) to change the diameter of the guide for the drilling and k-wire steps. In certain embodiments, a k-wire is not used and the trajectory is instead preserved within the memory of a computing device. The surgeon then retracts the surgical instrument guide ( 918 ). In some embodiments, the surgeon can reverse the motion of the surgical instrument guide along the trajectory, thereby decreasing incidental stresses on the k-wire. In certain embodiments, the k-wire is a flexible k-wire, which assists in removal of the surgical guide. The flexible k-wire allows the k-wire to bend while the surgical instrument guide is retracted, and the k-wire returns to the trajectory position once the surgical instrument guide has been fully retracted. 
         [0128]    After or prior to insertion of the k-wire, the surgeon may expand the working channel by placing progressively larger dilators around the k-wire and/or surgical instrument guide ( 920 ), as described in the present disclosure. The surgeon then taps the hole in the vertebrae sliding the tap along (e.g., over) the k-wire ( 922 ). In certain embodiments, the tapping step may be omitted. In other embodiments, if a k-wire is not used, the surgeon can locate the hole by retrieving the trajectory stored in computer memory and displaying the trajectory to the surgeon on the navigation display. At this stage, the dilators may be removed ( 924 ), or they may be removed at any other convenient point (e.g., any time after drilling). The screw is then placed by sliding the screw driver along (e.g., over) the k-wire ( 926 ). In certain embodiments, if a k-wire is not used, the surgeon can locate the hole by retrieving the trajectory stored in computer memory and displaying the trajectory to the surgeon on the navigation display. In some embodiments, the screw comprises an extensor attached to the back of the screw. This simplifies finding the screw later when placing rods. The screwdriver is removed from the patient while the screw remains in the patient ( 928 ). If desired, additional screws may be inserted by repeating the procedure at the appropriate location ( 930 ). 
         [0129]      FIG. 10  is an intraoperative medical image showing a vertebrae before placing the screw.  FIG. 11  is a postoperative medical image showing vertebrae with screws in place.  FIG. 12  is a volumetric medical image showing small skin incisions after percutaneous screw placement, according to an embodiment of the present disclosure.  FIG. 13  is a volumetric medical image showing screws placed in the vertebrae, according to an embodiment of the present disclosure. 
         [0130]    As shown in  FIG. 14 , an implementation of a network environment  1400  for use in performing minimally invasive surgical techniques is shown and described. In brief overview, referring now to  FIG. 14 , a block diagram of an exemplary cloud computing environment  1400  is shown and described. The cloud computing environment  1400  may include one or more resource providers  1402   a ,  1402   b ,  1402   c  (collectively,  1402 ). Each resource provider  1402  may include computing resources. In some implementations, computing resources may include any hardware and/or software used to process data. For example, computing resources may include hardware and/or software capable of executing algorithms, computer programs, and/or computer applications. In some implementations, exemplary computing resources may include application servers and/or databases with storage and retrieval capabilities. Each resource provider  1402  may be connected to any other resource provider  1402  in the cloud computing environment  1400 . In some implementations, the resource providers  1402  may be connected over a computer network  1408 . Each resource provider  1402  may be connected to one or more computing device  1404   a ,  1404   b ,  1404   c  (collectively,  1404 ), over the computer network  1408 . 
         [0131]    The cloud computing environment  1400  may include a resource manager  1406 . The resource manager  1406  may be connected to the resource providers  1402  and the computing devices  1404  over the computer network  1408 . In some implementations, the resource manager  1406  may facilitate the provision of computing resources by one or more resource providers  1402  to one or more computing devices  1404 . The resource manager  1406  may receive a request for a computing resource from a particular computing device  1404 . The resource manager  1406  may identify one or more resource providers  1402  capable of providing the computing resource requested by the computing device  1404 . The resource manager  1406  may select a resource provider  1402  to provide the computing resource. The resource manager  1406  may facilitate a connection between the resource provider  1402  and a particular computing device  1404 . In some implementations, the resource manager  1406  may establish a connection between a particular resource provider  1402  and a particular computing device  1404 . In some implementations, the resource manager  1406  may redirect a particular computing device  1404  to a particular resource provider  1402  with the requested computing resource. 
         [0132]      FIG. 15  shows an example of a computing device  1500  and a mobile computing device  1550  that can be used to implement the techniques described in this disclosure. The computing device  1500  is intended to represent various forms of digital computers, such as laptops, desktops, workstations, personal digital assistants, servers, blade servers, mainframes, and other appropriate computers. The mobile computing device  1550  is intended to represent various forms of mobile devices, such as personal digital assistants, cellular telephones, smart-phones, and other similar computing devices. The components shown here, their connections and relationships, and their functions, are meant to be examples only, and are not meant to be limiting. 
         [0133]    The computing device  1500  includes a processor  1502 , a memory  1504 , a storage device  1506 , a high-speed interface  1508  connecting to the memory  1504  and multiple high-speed expansion ports  1510 , and a low-speed interface  1512  connecting to a low-speed expansion port  1514  and the storage device  1506 . Each of the processor  1502 , the memory  1504 , the storage device  1506 , the high-speed interface  1508 , the high-speed expansion ports  1510 , and the low-speed interface  1512 , are interconnected using various busses, and may be mounted on a common motherboard or in other manners as appropriate. The processor  1502  can process instructions for execution within the computing device  1500 , including instructions stored in the memory  1504  or on the storage device  1506  to display graphical information for a GUI on an external input/output device, such as a display  1516  coupled to the high-speed interface  1508 . In other implementations, multiple processors and/or multiple buses may be used, as appropriate, along with multiple memories and types of memory. Also, multiple computing devices may be connected, with each device providing portions of the necessary operations (e.g., as a server bank, a group of blade servers, or a multi-processor system). 
         [0134]    The memory  1504  stores information within the computing device  1500 . In some implementations, the memory  1504  is a volatile memory unit or units. In some implementations, the memory  1504  is a non-volatile memory unit or units. The memory  1504  may also be another form of computer-readable medium, such as a magnetic or optical disk. 
         [0135]    The storage device  1506  is capable of providing mass storage for the computing device  1500 . In some implementations, the storage device  1506  may be or contain a computer-readable medium, such as a floppy disk device, a hard disk device, an optical disk device, or a tape device, a flash memory or other similar solid state memory device, or an array of devices, including devices in a storage area network or other configurations. Instructions can be stored in an information carrier. The instructions, when executed by one or more processing devices (for example, processor  1502 ), perform one or more methods, such as those described above. The instructions can also be stored by one or more storage devices such as computer- or machine-readable mediums (for example, the memory  1504 , the storage device  1506 , or memory on the processor  1502 ). 
         [0136]    The high-speed interface  1508  manages bandwidth-intensive operations for the computing device  1500 , while the low-speed interface  1512  manages lower bandwidth-intensive operations. Such allocation of functions is an example only. In some implementations, the high-speed interface  1508  is coupled to the memory  1504 , the display  1516  (e.g., through a graphics processor or accelerator), and to the high-speed expansion ports  1510 , which may accept various expansion cards (not shown). In the implementation, the low-speed interface  1512  is coupled to the storage device  1506  and the low-speed expansion port  1514 . The low-speed expansion port  1514 , which may include various communication ports (e.g., USB, Bluetooth®, Ethernet, wireless Ethernet) may be coupled to one or more input/output devices, such as a keyboard, a pointing device, a scanner, or a networking device such as a switch or router, e.g., through a network adapter. 
         [0137]    The computing device  1500  may be implemented in a number of different forms, as shown in the figure. For example, it may be implemented as a standard server  1520 , or multiple times in a group of such servers. In addition, it may be implemented in a personal computer such as a laptop computer  1522 . It may also be implemented as part of a rack server system  1524 . Alternatively, components from the computing device  1500  may be combined with other components in a mobile device (not shown), such as a mobile computing device  1550 . Each of such devices may contain one or more of the computing device  1500  and the mobile computing device  1550 , and an entire system may be made up of multiple computing devices communicating with each other. 
         [0138]    The mobile computing device  1550  includes a processor  1552 , a memory  1564 , an input/output device such as a display  1554 , a communication interface  1566 , and a transceiver  1568 , among other components. The mobile computing device  1550  may also be provided with a storage device, such as a micro-drive or other device, to provide additional storage. Each of the processor  1552 , the memory  1564 , the display  1554 , the communication interface  1566 , and the transceiver  1568 , are interconnected using various buses, and several of the components may be mounted on a common motherboard or in other manners as appropriate. 
         [0139]    The processor  1552  can execute instructions within the mobile computing device  1550 , including instructions stored in the memory  1564 . The processor  1552  may be implemented as a chipset of chips that include separate and multiple analog and digital processors. The processor  1552  may provide, for example, for coordination of the other components of the mobile computing device  1550 , such as control of user interfaces, applications run by the mobile computing device  1550 , and wireless communication by the mobile computing device  1550 . 
         [0140]    The processor  1552  may communicate with a user through a control interface  1558  and a display interface  1556  coupled to the display  1554 . The display  1554  may be, for example, a TFT (Thin-Film-Transistor Liquid Crystal Display) display or an OLED (Organic Light Emitting Diode) display, or other appropriate display technology. The display interface  1556  may comprise appropriate circuitry for driving the display  1554  to present graphical and other information to a user. The control interface  1558  may receive commands from a user and convert them for submission to the processor  1552 . In addition, an external interface  1562  may provide communication with the processor  1552 , so as to enable near area communication of the mobile computing device  1550  with other devices. The external interface  1562  may provide, for example, for wired communication in some implementations, or for wireless communication in other implementations, and multiple interfaces may also be used. 
         [0141]    The memory  1564  stores information within the mobile computing device  1550 . The memory  1564  can be implemented as one or more of a computer-readable medium or media, a volatile memory unit or units, or a non-volatile memory unit or units. An expansion memory  1574  may also be provided and connected to the mobile computing device  1550  through an expansion interface  1572 , which may include, for example, a SIMM (Single In Line Memory Module) card interface. The expansion memory  1574  may provide extra storage space for the mobile computing device  1550 , or may also store applications or other information for the mobile computing device  1550 . Specifically, the expansion memory  1574  may include instructions to carry out or supplement the processes described above, and may include secure information also. Thus, for example, the expansion memory  1574  may be provided as a security module for the mobile computing device  1550 , and may be programmed with instructions that permit secure use of the mobile computing device  1550 . In addition, secure applications may be provided via the SIMM cards, along with additional information, such as placing identifying information on the SIMM card in a non-hackable manner. 
         [0142]    The memory may include, for example, flash memory and/or NVRAM memory (non-volatile random access memory), as discussed below. In some implementations, instructions are stored in an information carrier and, when executed by one or more processing devices (for example, processor  1552 ), perform one or more methods, such as those described above. The instructions can also be stored by one or more storage devices, such as one or more computer- or machine-readable mediums (for example, the memory  1564 , the expansion memory  1574 , or memory on the processor  1552 ). In some implementations, the instructions can be received in a propagated signal, for example, over the transceiver  1568  or the external interface  1562 . 
         [0143]    The mobile computing device  1550  may communicate wirelessly through the communication interface  1566 , which may include digital signal processing circuitry where necessary. The communication interface  1566  may provide for communications under various modes or protocols, such as GSM voice calls (Global System for Mobile communications), SMS (Short Message Service), EMS (Enhanced Messaging Service), or MMS messaging (Multimedia Messaging Service), CDMA (code division multiple access), TDMA (time division multiple access), PDC (Personal Digital Cellular), WCDMA (Wideband Code Division Multiple Access), CDMA2000, or GPRS (General Packet Radio Service), among others. Such communication may occur, for example, through the transceiver  1568  using a radio-frequency. In addition, short-range communication may occur, such as using a Bluetooth®, Wi-Fi™, or other such transceiver (not shown). In addition, a GPS (Global Positioning System) receiver module  1570  may provide additional navigation- and location-related wireless data to the mobile computing device  1550 , which may be used as appropriate by applications running on the mobile computing device  1550 . 
         [0144]    The mobile computing device  1550  may also communicate audibly using an audio codec  1560 , which may receive spoken information from a user and convert it to usable digital information. The audio codec  1560  may likewise generate audible sound for a user, such as through a speaker, e.g., in a handset of the mobile computing device  1550 . Such sound may include sound from voice telephone calls, may include recorded sound (e.g., voice messages, music files, etc.) and may also include sound generated by applications operating on the mobile computing device  1550 . 
         [0145]    The mobile computing device  1550  may be implemented in a number of different forms, as shown in the figure. For example, it may be implemented as a cellular telephone  1580 . It may also be implemented as part of a smart-phone  1582 , personal digital assistant, or other similar mobile device. 
         [0146]    Various implementations of the systems and techniques described here can be realized in digital electronic circuitry, integrated circuitry, specially designed ASICs (application specific integrated circuits), computer hardware, firmware, software, and/or combinations thereof. These various implementations can include implementation in one or more computer programs that are executable and/or interpretable on a programmable system including at least one programmable processor, which may be special or general purpose, coupled to receive data and instructions from, and to transmit data and instructions to, a storage system, at least one input device, and at least one output device. 
         [0147]    These computer programs (also known as programs, software, software applications or code) include machine instructions for a programmable processor, and can be implemented in a high-level procedural and/or object-oriented programming language, and/or in assembly/machine language. As used herein, the terms machine-readable medium and computer-readable medium refer to any computer program product, apparatus and/or device (e.g., magnetic discs, optical disks, memory, Programmable Logic Devices (PLDs)) used to provide machine instructions and/or data to a programmable processor, including a machine-readable medium that receives machine instructions as a machine-readable signal. The term machine-readable signal refers to any signal used to provide machine instructions and/or data to a programmable processor. 
         [0148]    To provide for interaction with a user, the systems and techniques described here can be implemented on a computer having a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user and a keyboard and a pointing device (e.g., a mouse or a trackball) by which the user can provide input to the computer. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form, including acoustic, speech, or tactile input. 
         [0149]    The systems and techniques described here can be implemented in a computing system that includes a back end component (e.g., as a data server), or that includes a middleware component (e.g., an application server), or that includes a front end component (e.g., a client computer having a graphical user interface or a Web browser through which a user can interact with an implementation of the systems and techniques described here), or any combination of such back end, middleware, or front end components. The components of the system can be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include a local area network (LAN), a wide area network (WAN), and the Internet. 
         [0150]    The computing system can include clients and servers. A client and server are generally remote from each other and typically interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other. 
         [0151]    In view of the structure, functions and apparatus of the systems and methods described here, in some implementations, a system and method for performing minimally invasive surgical techniques are provided. Having described certain implementations of methods and apparatus for supporting minimally invasive surgical techniques, it will now become apparent to one of skill in the art that other implementations incorporating the concepts of the disclosure may be used. Therefore, the disclosure should not be limited to certain implementations, but rather should be limited only by the spirit and scope of the following claims. 
         [0152]    Throughout the description, where apparatus and systems are described as having, including, or comprising specific components, or where processes and methods are described as having, including, or comprising specific steps, it is contemplated that, additionally, there are apparatus, and systems of the disclosed technology that consist essentially of, or consist of, the recited components, and that there are processes and methods according to the disclosed technology that consist essentially of, or consist of, the recited processing steps. 
         [0153]    It should be understood that the order of steps or order for performing certain action is immaterial so long as the disclosed technology remains operable. Moreover, two or more steps or actions may be conducted simultaneously.