Systems and methods for intraoperatively measuring anatomical orientation

Systems and methods are disclosed in which changes in the position and/or orientation of an anatomical structure or of a surgical tool can be measured quantitatively during surgery. In some embodiments, the systems and methods disclosed herein can make use of inertial motion sensors to determine a position or orientation of an instrument or anatomy at different times and to calculate changes between different positions or orientations. In other embodiments, such sensors can be utilized in conjunction with imaging devices to correlate sensor position with anatomical landmarks, thereby permitting determination of absolute angular orientation of a landmark. Such systems and methods can facilitate real-time tracking of progress during a variety of procedures, including, e.g., spinal deformity correction, etc.

FIELD

The present disclosure is related to systems and methods for measuring anatomical position and/or orientation. In some embodiments, systems and methods quantitatively measure changes in the position and/or orientation of a portion of a patient's anatomy with respect to another portion of the patient's anatomy during surgery.

BACKGROUND

Many surgical procedures require a surgeon to intraoperatively assess changes in the position or orientation of one or more portions of a patient's anatomy. However, even in open surgeries, there can be obstructions that prevent a surgeon from viewing relevant anatomy at a surgical site, e.g., blood, adjacent soft tissue, etc. Traditional surgical procedures use imaging techniques, such as CT-scans, x-rays, etc., to pre-operatively plan for a desired anatomical correction and then to post-operatively assess whether the desired anatomical correction has been achieved. Viewing the anatomical changes intraoperatively using such imaging techniques can be difficult, however, as it may require interruption of the surgery. Also, many imaging techniques only provide snapshots illustrating progressive changes in a qualitative manner, but do not provide data of changes as they occur in real-time. A further limitation of such imaging techniques is that they may only provide qualitative data, thus requiring a surgeon to make a subjective assessment of when a desired anatomical orientation has been achieved. Such imaging techniques also expose the patient and the operating room staff to potentially-harmful radiation.

During a traditional pedicle subtraction osteotomy, surgeons remove bone from a vertebra of a patient suffering from a spinal deformity to correct spinal curvature. To intraoperatively determine when the appropriate amount of bone has been removed, the surgeon must be able to accurately assess the amount of correction that has been achieved at a given time. Traditionally, to make this assessment, the surgeon must step back from the surgical procedure while an imaging device is brought in and positioned to view the curvature of the spine. However, this provides only a subjective measure of angular correction and involves an interruption in the surgical procedure, adding time and inconvenience. Often times, this results in sub-optimal patient outcomes and repeat surgeries due to over- or under-correction of the deformity.

Thus, there is a need for improved systems and methods for intraoperatively measuring anatomical position and/or orientation.

SUMMARY

Systems and methods are disclosed in which changes in the position and/or orientation of an anatomical structure or of a surgical tool can be measured quantitatively during surgery. In some embodiments, a surgical electronic module can be configured to attach to a portion of a patient's anatomy and/or to a surgical device, to continually detect changes in a position and/or orientation of the patient's anatomy and/or the surgical device during surgery, and to communicate the changes to a user. Where the surgical device is attached to a portion of a patient's anatomy and/or is used to manipulate the patient's anatomy, the surgical electronic module can detect changes in the position and/or orientation of said anatomy. In embodiments where more than one module is used during surgery, the modules can continually detect changes in their positions and/or orientations relative to one another, which correspond to changes in relative positions and/or orientations of portions of the patient's anatomy and/or the surgical devices to which the modules are attached.

In one exemplary embodiment, a surgical electronic module is provided that includes a housing having one or more engagement features that are configured to removably attach the housing to a surgical device, a sensor, a processor, and a display. The sensor can be disposed in the housing and can be configured to detect a position or orientation of the module with respect to the earth. The processor can be coupled to the sensor and can be configured to calculate a change in position or orientation of the surgical device with respect to one or more reference points when the surgical device is attached to the module, based on the position or orientation detected by the sensor. The display can be configured to display the change calculated by the processor to thereby assist a user in assessing changes in position or orientation of anatomy coupled to or manipulated by the surgical device. In some embodiments, the display can be disposed on the housing.

In some embodiments, the surgical electronic module can include additional components. By way of non-limiting example, the surgical electronic module can further include a reset mechanism that, when actuated, sets an initial position or orientation of the module to be used in calculating the change in the position or orientation of the surgical device. Additionally or alternatively, the surgical electronic module can include a memory configured to store at least one of the position or orientation detected by the sensor and the change calculated by the processor. In still further embodiments, the surgical electronic module can include a communications interface configured to send the position or orientation detected by the sensor to an external device and to receive a position or orientation of the one or more reference points from the external device. The external device can be a second surgical electronic module.

In some embodiments, the one or more reference points can include a second surgical electronic module. In some embodiments, the sensor can be configured to detect the position or orientation at predetermined time intervals and/or the processor can be configured to calculate the change at the predetermined time intervals. The processor can further be configured to calculate first, second, and/or third derivatives of the position or orientation of the surgical device. In still further embodiments, the one or more engagement features can be configured to identify an aspect of the surgical device when the surgical device is attached to the module.

In another aspect, a surgical method is provided for measuring a change in anatomical position or orientation. The method can involve detecting an absolute angle of a first electronic module attached to a first surgical device by a sensor of the first electronic module, with the first surgical device being operatively coupled with a first portion of a patient's anatomy and detecting an absolute angle of a second electronic module attached to a second surgical device by a sensor of the second electronic module, with the second surgical device being operatively coupled with a second portion of the patient's anatomy. The method can also include calculating by a processor of at least one of the first and second electronic modules a change in an angle of the first electronic module with respect to the second electronic module multiple times during a surgery to determine a change in an angle of the first surgical device with respect to the second surgical device. The method can further include conveying to a user the change in the angle of the first surgical device with respect to the second surgical device to thereby assist the user in determining a change in an angle of the first portion of the patient's anatomy with respect to the second portion of the patient's anatomy. In some embodiments, the change in the angle of the first surgical device with respect to the second surgical device is conveyed to the user on a display of at least one of the first electronic module and the second electronic module.

In some embodiments, the method can further include actuating reset mechanisms of the first and second electronic modules to set an initial angle of the first module with respect to the second module. The initial angle can be used in calculating the change in the angle of the modules relative to one another. The calculating and the conveying steps can be repeated until a target position or orientation of the first surgical device with respect to the second surgical device has been reached. In such embodiments, the method can further include alerting the user when the target position or orientation has been reached. In still further embodiments, the method can include calculating a rate of the change in the angle of the first surgical device with respect to the second surgical device.

In some embodiments, the first and second portions of the patient's anatomy are first and second vertebra on opposite sides of an osteotomy site. When the first portion of the patient's anatomy is a first vertebra and the first surgical device is a first bone screw implanted in the first vertebra, the method can further include attaching the first electronic module to the first bone screw. Additionally, when the second portion of the patient's anatomy is a second vertebra disposed opposite an osteotomy site from the first vertebra and the second surgical device is a second bone screw implanted in the second vertebra, the method can further include attaching the second electronic module to the second bone screw. In such embodiments, the method can also include locking a spinal rod to the first and second bone screws after a target position or orientation of the first vertebra with respect to the second vertebra has been reached.

In yet another aspect, a surgical method is provided for guiding a surgical instrument. The method can include detecting an orientation of a first electronic module that is attached to the surgical instrument by a sensor of the first electronic module, detecting a position of the first electronic module via communications between the first electronic module and at least two electronic modules attached to at least two surgical devices, calculating by a processor of the first electronic module a change in the orientation of the surgical instrument and a change in the position of the surgical instrument over time, and conveying to a user the change in the orientation and the position of the surgical instrument to thereby assist the user in guiding the surgical instrument during surgery. In some embodiments, the change in the position and the orientation of the surgical instrument is conveyed to the user on a display of the first electronic module. In some embodiments, the at least two surgical devices do not move with respect to a patient's anatomy while the user is guiding the surgical instrument.

In another aspect, a surgical electronic module is provided that can include a housing, a sensor disposed in the housing and configured to detect a position or orientation of the module, an input disposed on an outer surface of the housing, and a processor coupled to the sensor and configured to record the position or orientation of the module in response to instruction from the input. The processor can be further configured to simultaneously calculate a change in position or orientation of the module in two orthogonal planes with respect to a reference point based on the position or orientation detected by the sensor. The module can also include a display configured to display the change calculated by the processor to thereby assist a user in assessing changes in position or orientation of anatomy coupled to the module.

Any of a variety of additional features or substitutions are possible. For example, in some embodiments the housing can include an engagement feature configured to removably attach the housing to a surgical instrument. In other embodiments, however, the module can be integrally formed in a surgical instrument. Any of a variety of surgical instruments can be utilized, including, for example, any of an osteotome, a chisel, a deformity correction instrument, a probe, an awl, a drill, a tap, and a gearshift.

The sensor included in the electronic module can be an inertial motion sensor that can include any of an accelerometer, a gyroscope, and a magnetometer. In some embodiments, for example, the sensor can be a 9-axis inertial motion sensor which can include an accelerometer, a gyroscope, and a magnetometer. In other embodiments, alternative sensors can be utilized that can include a subset of these components, e.g., an inertial motion sensor including solely a 3-axis accelerometer, a “10-axis” sensor including an altimeter, an “11-axis” sensor including a temperature sensor, etc. Moreover, in some embodiments a sensor can be configured to utilize only a subset of its available components, e.g., a 9-axis sensor having an accelerometer, a gyroscope, and a magnetometer that can be configured to make use of, for example, only the accelerometer and the gyroscope (thereby forming an effective “6-axis” sensor). In other embodiments various other sensors can be employed that can provide position and/or orientation information.

The input can have a variety of forms. In some embodiments, for example, the input can be a single button. In other embodiments, the input can include a plurality of buttons (e.g., 4 buttons, 5 buttons, etc.). In still other embodiments, button alternatives can be utilized, including switches, pressure sensitive sensors, etc. The buttons, switches, etc. can each be selectively lighted in some embodiments to provide feedback to a user and/or to prompt a user for input (e.g., a first button can light up to prompt recording of a first position or orientation, and a second button can light up to prompt recording of a second position or orientation).

As described in more detail below, in some embodiments the electronic module can be configured to calculate changes between two positions and project those changes into a previously-defined orthogonal reference planes. In some embodiments, the module can include a reference plane alignment feature for defining the two orthogonal planes. The reference plane alignment feature can be an extended ridge, protrusion, or other feature formed on the housing in some embodiments.

In one aspect, a surgical method is provided that can include positioning a surgical instrument in a first position or orientation relative to anatomy, receiving instruction from an input and recording the first position or orientation using a sensor coupled to the surgical instrument and configured to detect a position or orientation thereof, positioning the surgical instrument in a second position or orientation relative to anatomy, receiving instruction from the input and recording the second position or orientation using the sensor, calculating changes in position or orientation between the first and second positions or orientations in two orthogonal planes, and displaying the changes in position or orientation in the two orthogonal planes using a display coupled to the surgical instrument.

As with the module described above, a number of variations and additions are possible. For example, in some embodiments the method can further include coupling a surgical electronic module including the sensor and the display to the surgical instrument, whereas in other embodiments the sensor and the display can be integrally formed in the surgical instrument. Any of a variety of surgical instruments can be utilized and, in some embodiments, the surgical instrument can be any of an osteotome, a chisel, a deformity correction instrument, a probe, an awl, a drill, a tap, and a gearshift.

As noted above, in some embodiments the input can be a single button, while in other embodiments the input can be a plurality of buttons. In still other embodiments, any of a variety of button alternatives, such as switches, pressure-sensitive sensors, etc., can be utilized. In an embodiment in which a plurality of buttons is utilized, the method can further include resetting any of the recorded first and second positions or orientations in response to simultaneous depression of more than one button.

In some embodiments, the method can further include positioning the surgical instrument in a third position or orientation relative to anatomy, receiving instruction from the input and recording the third position or orientation using the sensor, positioning the surgical instrument in a fourth position or orientation relative to anatomy, and receiving instruction from the input and recording the fourth position or orientation using the sensor. The method can also include calculating changes in position or orientation between the third and fourth positions or orientations as projected onto a first plane defined between the first and second positions or orientations and a second plane orthogonal to the first plane, and displaying the changes in position or orientation between the third and fourth positions or orientations using the display. In this manner, the first and second positions of the surgical instrument recorded by the sensor can be used to define a first reference plane and a second reference plane orthogonal thereto, and position/orientation changes between third and fourth positions can be projected onto the two reference planes.

In another aspect, a method for performing bone or tissue correction or manipulation is provided that can include coupling first and second sensors to respective first and second portions of a patient's anatomy, and actuating an imaging device to capture an image of the first and second portions of the anatomy with the first and second sensors coupled thereto. The method can further include utilizing the image of the first and second portions of the anatomy in a simulated environment to identify a desired anatomical landmark with respect to each of the attached sensors, as well as, using a processor, determining a compensatory angle between each sensor and its respective anatomical landmark, and utilizing the compensatory angles and a measured angle between the first and second sensors to calculate an absolute anatomical angular orientation of the landmarks.

In some embodiments, coupling the first and second sensors can include implanting the first and second sensors in the patient. Further, in some embodiments the first and second sensors can be percutaneously implanted in the patient. As explained in more detail below, in some embodiments a mount can be employed to achieve percutaneous implantation of a sensor.

In some embodiments, the absolute angular orientation can be calculated in real-time or substantially in real-time, thereby providing a constant update to a surgeon or other user without the need to interrupt a procedure. In still other embodiments, the method can further include coupling a reference plane sensor to a patient's anatomy to define a reference plane in which angular orientation can be measured. In some embodiments, the reference plane sensor can be used to define a first reference plane and a second reference plane orthogonal to the first reference plane.

In another aspect, a method of measuring an absolute spinal angle is provided that can include coupling first and second sensors to respective first and second portions of a patient's spine, as well as capturing at least one image of the first and second sensors and the patient's spine using an imaging device. The method can further include identifying in the at least one captured image first and second vertebral endplates that define the absolute spinal angle to be measured, calculating, by a processor, a first compensation angle between the first endplate and the first sensor in the at least one captured image, and calculating, by a processor, a second compensation angle between the second endplate and the second sensor in the at least one captured image. The method can also include obtaining a relative angle measured between the first and second sensors, adjusting, by a processor, the relative angle based on the first and second compensation angles to calculate the absolute spinal angle, and communicating the absolute spinal angle to a user.

In some embodiments, the absolute spinal angle can be calculated and communicated to the user in real-time or substantially in real-time. Further, in some embodiments the absolute spinal angle can be at least one of lumbar lordosis and thoracic kyphosis.

In certain embodiments, communicating the absolute spinal angle can include displaying the angle on an electronic display. In other embodiments, different communication methods can be employed, such as audio communication through a speaker, or combinations of audio, visual, and tactile feedback. Further, in some embodiments, identifying the endplates can include interacting with a graphical user interface that displays the at least one captured image to select the endplates with an input device.

As with the method described above, in some embodiments coupling the first and second sensors can include implanting the first and second sensors in the patient. Moreover, in certain embodiments the first and second sensors can be percutaneously implanted in the patient. This can be accomplished in some embodiments using a percutaneous mount configured to receive a sensor and to extend into a patient.

In still another aspect, a surgical system is provided that can include a first sensor configured to couple to a first portion of a patient's anatomy, a second sensor configured to couple a second portion of the patient's anatomy, and an imaging device configured to capture an image of the patient's anatomy and the first and second sensors. The system can further include a processor configured to receive via an input identification of a desired anatomical landmark with respect to one of the first and second sensors, and determine a compensatory angle between each sensor and its respective anatomical landmark, wherein the processor is further configured to calculate an absolute anatomical angular orientation of the landmarks utilizing the compensatory angles and a measured angle between the first and second sensors. The system can further include a display configured to display the captured image and calculated absolute anatomical angular orientation of the landmarks.

The system can include a number of additions or variations. For example, in some embodiments the system can further include a reference plane sensor configured to be coupled to the patient's anatomy to define a reference plane in which angular orientation can be measured. In certain embodiments, the reference plane sensor can also define a second reference plane orthogonal to the reference plane. In some embodiments, the reference plane sensor can be direction-specific, e.g., a first end can be configured to point toward a user's head or other portion of anatomy while a second end can be configured to point toward a user's feet or other portion of anatomy. In such an embodiment, the reference plane sensor can include an orientation indicator to aid a user in aligning the reference plane sensor. An orientation indicator can be an arrow or other marking in some embodiments. In other embodiments, the reference plane sensor can be formed in the shape of a human patient such that a surgeon or other user can intuitively align the shape of the reference plane sensor with the shape of the patient during use.

In some embodiments, each of the first and second sensors can be an inertial motion sensor including any of an accelerometer, a gyroscope, and a magnetometer. For example, in some embodiments the sensor can be a 9-axis inertial motion sensor including an accelerometer, a gyroscope, and a magnetometer. In other embodiments, different inertial motion sensors can be utilized having a subset of these components. For example, in some embodiments a sensor having solely a 3-axis accelerometer can be employed, etc.

In some embodiments, each of the first and second sensors can be radiopaque to facilitate capture of the sensors by the imaging device. For example, if the imaging device is configured to capture X-ray images, radiopaque sensors can be clearly visible in the captured images.

As noted above, in some embodiments the first and second sensors can be implanted in a patient and, in certain embodiments, can be implanted percutaneously. In some embodiments, the system can further include first and second mounts configured to permit percutaneous coupling of the first and second sensors to the patient's anatomy. Each of the first and second mounts can include a needle-shaped distal portion for percutaneous insertion through a patient's skin and a proximal recess configured to receive one of the first and second sensors therewithin.

Any of the features or variations described above can be applied to any particular aspect or embodiment of the disclosure in a number of different combinations. The absence of explicit recitation of any particular combination is due solely to the avoidance of repetition in this summary.

DETAILED DESCRIPTION

In the present disclosure, like-numbered components of the embodiments generally have similar features and/or purposes. Further, to the extent that linear or circular dimensions are used in the description of the disclosed systems, devices, and methods, such dimensions are not intended to limit the types of shapes that can be used in conjunction with such systems, devices, and methods. A person skilled in the art will recognize that an equivalent to such linear and circular dimensions can easily be determined for any geometric shape. Sizes and shapes of the systems and devices, and the components thereof, can depend at least on the size and shape of the components with which the systems and devices are being used, the anatomy of the patient, and the methods and procedures in which the systems and devices will be used. The figures provided herein are not necessarily to scale.

Systems and methods are disclosed in which changes in a position and/or orientation of an anatomical structure or of a surgical tool can be measured quantitatively during surgery. In some embodiments, a surgical electronic module can be configured to attach to a surgical device, to continually detect changes in a position and/or orientation of the surgical device during surgery, and to communicate the changes to a user. In this way, where the surgical device is attached to a portion of a patient's anatomy and/or is used to manipulate the patient's anatomy, the surgical electronic module can detect changes in the position and/or orientation of said anatomy. In embodiments where more than one module is used during surgery, the modules can continually detect changes in their positions and/or orientations relative to one another, which correspond to changes in relative positions and/or orientations of the surgical devices to which the modules are attached. Additionally or alternatively, at least one of the modules can help to establish a reference 3D location in the operating room, particularly where the at least one of the modules is stationary. In some embodiments, the modules can include a resetting or “zeroing” function that allows a user to selectively set an initial relative position and/or orientation of the modules to zero. Subsequent changes in the relative positions and/or orientations of the modules can then be measured and displayed to the user so that the user knows when a desired change in position and/or orientation of the modules has been reached. In some embodiments, all of the components necessary for detecting, calculating, and/or communicating positional information (i.e., position and/or orientation) are contained within the module itself, thus eliminating the need for an external base station or other additional bulky equipment. By thus providing a means for quantitatively measuring changes in anatomical orientation in real-time during surgery, exemplary systems and methods provided herein can enhance the accuracy of the surgery and reduce or eliminate the need for intraoperative imaging, thereby reducing radiation exposure and increasing efficiency.

The positional information detected and/or calculated by the surgical electronic module can include one or more angles of the module with respect to the earth (referred to hereinafter as “absolute” angles), one or more angles of the module with respect to a some other reference point (referred to hereinafter as “relative” angles), distances between the module and one or more external reference points, changes in any of these values, a rate of changes in any of these values, and/or higher order derivatives of any of these values. The module can be configured to detect and/or calculate the positional information in a variety of units and coordinate systems. To provide relevant anatomical measurements during surgery, in some embodiments the module can be configured to translate positions and/or orientations detected in a spherical coordinate system, illustrated inFIG. 1Aand defined by an absolute azimuth angle θ, an absolute polar angle φ, and a radial distance r, into positions and/or orientations along the sagittal, axial, and coronal planes, illustrated inFIG. 1B.

The surgical electronic module can include one or more components for detecting, processing, communicating, and/or storing positional information of the module and the surgical device to which it is attached. As schematically illustrated inFIG. 2, an exemplary module10can include a processor22, a memory24, a communications interface26, and a sensor28—all of which can be in communication with each other. Any of these components can exist external to the module10, however, for example at a remote base station configured to communicate with the module10through the communications interface26. Further, although each of these components are referred to in the singular, it will be appreciated by a person skilled in the art that the various functions described as being carried out by one of the components can actually be carried out by multiple of those components, e.g., the functions described as being carried out by the processor22can be carried out by multiple processors. The electrical components can be powered by a battery contained within the module10, for example a lithium ion battery, or can be powered by an external power source coupled to the module10via an adaptor.

The sensor28can be or can include any type of sensor that is configured to detect positional information of the module10. By way of non-limiting example, the sensor28can include an accelerometer (e.g., a 9-axis accelerometer for measuring one or more angles of the module10with respect to a reference point such as the earth), a gyroscopic sensor, a geomagnetic sensor, and the like. Additionally or alternatively, where the module10is configured to detect a distance of the module from a reference point, the sensor28can include ultrasound, electromagnetic, and/or infrared transceivers for communicating with a positioning system. In an exemplary embodiment, the sensor28can be configured to detect an absolute position and/or orientation of the module in the spherical coordinate system. The sensor28can be configured to detect the positional information at intervals throughout a surgical procedure, for example every second, every millisecond, every microsecond, etc., such that the positional information is effectively detected continuously and in real-time. The positional information can be detected regularly, intermittently, or at non-regular intervals. The positional information can be conveyed to the surgeon, stored in the memory24, conveyed to the processor22for processing, and/or communicated to one or more external devices via the communications interface26for processing or storage.

Where the sensor28is configured to detect both an orientation and a position (e.g., a distance of the module10from some reference point), the module10can be configured to switch between an orientation detection mode in which the sensor28detects only the orientation and a full detection mode in which the sensor28detects both the orientation and the position. The module10can be configured to switch between the orientation detection mode and the full detection mode at the request of the surgeon, for example via actuation of an input device on the module10, and/or based on an identity of the surgical device to which the module10is attached.

The processor22can include a microcontroller, a microcomputer, a programmable logic controller (PLC), a field-programmable gate array (FPGA), an application specific integrated circuit (ASIC), integrated circuits generally referred to in the art as a computer, and other programmable circuits, and these terms are used interchangeably herein. The processor22can be configured to generate positional information and/or perform various calculations based on the positional information detected by the sensor28, stored in the memory24, and/or received from an external device via the communications interface26. By way of non-limiting example, the processor22can be configured to calculate a relative position and/or orientation of the module10with respect to an external reference point based on an absolute position and/or orientation of the module10that is detected by the sensor28and/or an absolute position and/or orientation of the external reference point that is received through the communications interface26. The processor22can be configured to calculate changes in the absolute and relative positions and/or orientations of the module10and/or a speed at which those changes occur, which will correspond to changes and/or a speed of the surgical device to which the module10is attached.

The processor22can be coupled to the memory24, which can include a random access memory (RAM), a read-only memory (ROM), a flash memory, a non-transitory computer readable storage medium, and so forth. The memory24can store instructions for execution by the processor22to implement the systems disclosed herein or to execute the methods disclosed herein. Additionally or alternatively, the memory24can store the positional information sensed by the sensor28, calculated by the processor22, and/or received from an external device through the communications interface26.

The communications interface26can be configured to receive and transmit information from any of the processor22, the memory24, and the sensor28with one or more external devices, e.g., another surgical electronic module, a base station, etc. The communications interface26be wireless (e.g., near-field communication (NFC), Wi-Fi, Bluetooth, Bluetooth LE, ZigBee, and the like) or wired (e.g., USB or Ethernet). In the case of NFC, for example, the module10can include a radio transceiver configured to communicate with a radio transceiver of another device, e.g., a second module, using one or more standards such as ISO/IEC 14443, FeliCa, ISO/IEC 18092, and those defined by the NFC Forum. The communication interface26can be selected to provide the desired communication range. In some embodiments, Bluetooth (e.g., class 2 Bluetooth having a range of 5-10 meters) can be used for the communication interface to allow the module10to remain somewhat distant from the device with which it is communicating, e.g., the second module and/or a base station, while at the same time limiting the communication range such that other mobile devices unlikely to be used in the surgery are not needlessly involved.

As shown inFIG. 3, the exemplary module10can include a proximal housing20and a distal shaft30. In general, the housing20and the shaft30can be any size and shape configured to be inserted at least partially into a patient's body during surgery while not substantially obstructing a surgeon's view of or access to a surgical site. Any or all of the above described components for detecting, processing, and/or communicating positional information can be housed within the housing20. Further, the housing20can have various external features for inputting and outputting the positional information, for example the housing20can include an electronic display50for communicating information detected and/or calculated by the module10and/or a zeroing button60to allow the user to indicate that the module10is in an initial position and/or orientation. The shaft30can extend distally from the housing20and can be configured to rigidly and mechanically attach the module10to the surgical device such that changes in the position and/or orientation of the surgical device result in corresponding changes in the position and/or orientation of the module10.

The display50can be configured to communicate the positional information detected and/or calculated by the module10to assist the surgeon in assessing anatomical changes effected by the surgical device to which the module10is attached. In the illustrated embodiment, the display50is formed on a proximal-facing surface of the housing20, although the display50can be located anywhere on the module10, e.g., such that it is visible to the surgeon during surgery, or it can be located remotely from the module. The display50can be any type of display screen, e.g., liquid crystal, light emitting diode, etc., and in some embodiments can be configured to withstand exposure to sterilization, liquids, and/or high levels of moisture. In an exemplary embodiment, the display50can display a change in the absolute or relative position and/or orientation of the module10during surgery, which corresponds to a change in the position and/or orientation of the surgical device to which the module10is attached. In some embodiments, the display50can additionally or alternatively provide positive and/or negative feedback to the surgeon about the position and/or orientation of the module10. By way of non-limiting example, when the module10detects that a desired position and/or orientation has been reached, the display50can provide positive feedback to the surgeon, e.g., a green light. When the module10is determined to be outside a desirable positional range, the display50can provide negative feedback to the surgeon, e.g., a red light, an error message, etc. Other means for communicating information to the surgeon can include, without limitation, a vibrator, a speaker or buzzer for providing audio feedback and an internal or external display in communication with the module10for providing visual feedback. The external display can be larger than the display50and, in some embodiments, can provide a real-time graphical illustration of the movement of the module10and optionally one or more other modules during surgery.

The positional information output by the module10, for example on the display50, can be reset to zero at any time by user actuation of a resetting or “zeroing” mechanism to thereby indicate that the module10is in an initial position and/or orientation. For example, a position and/or orientation of the module10displayed at a starting point of the surgery can to be set to zero upon actuation of the zeroing button60by the surgeon, although it will be appreciated by a person skilled in the art that the zeroing mechanism can be any feature on the module10or it can be remote to the module10. After the zeroing button60has been pressed, the display50can display a change in the position and/or orientation of the module10relative to a zero position and/or orientation, such that the surgeon can readily know the difference between the initial position and/or orientation of the module10and a current position and/or orientation of the module10. Thus, where the surgery requires changing a position and/or orientation of a patient's anatomy that is connected to the module10via the surgical device by a desired amount, the surgeon can know that the desired change has been effected when the desired change of the module10is displayed on the display50. In some embodiments, actuation of the button60can also initiate detection and/or calculation of the position and/or orientation of the module10.

The module10can be configured to attach directly to a patient's anatomy and/or to the surgical device via one or more engagement features40formed on a distal portion of the module10, for example on the distal end of the shaft30. The surgical device can be anything used in the operating room that facilitates the surgery, including, by way of non-limiting example, surgical implants, surgical instruments, fixtures in the operating room, e.g., an operating table, etc. The engagement features40can be specifically configured to mate the module10only to a single type of surgical device, or they can be adaptable or modular to allow for mating of the module10to any of a variety of surgical devices. Further, the engagement features40can be configured to mate the module10to more than one surgical device at a time. The engagement features40can provide for direct rigid mechanical attachment of the module10to the surgical device to thereby ensure that changes in a position and/or orientation of the surgical device result in corresponding changes in the position and/or orientation of the module10. In some embodiments, the engagement features40can be configured to rigidly attach to engagement features of another surgical electronic module to calibrate the module10with the other surgical electronic module, e.g., by synchronizing coordinate systems. Non-limiting examples of engagement features40include a snap mechanism, a lock-and-key mechanism, an electronic contact, a screw or other threaded feature, etc.

In some embodiments, the engagement features40can be configured to detect identification information about the surgical device to which the module10is attached. For example, the engagement features40can comprise one or more buttons, switches, pressure transducers, etc. that are configured to align with one or more protrusions on the surgical device. The number and arrangement of protrusions can serve to uniquely identify the surgical device. In this way, the number and arrangement of buttons or other components that are engaged by the one or more protrusions on the surgical device can convey identification information about the surgical device. In another embodiment, the engagement features40can include a radio frequency identification (RFID) transceiver or optical scanner that is configured to read a unique device identifier (UDI) contained in either an RFID tag or bar code, respectively, on the surgical device. The identification information can include a type of the surgical device, a serial number of the surgical device, an angle at which the surgical device is configured to attach to the module10, an age of the surgical device, an intended use of the surgical device, etc.

The identification information can be conveyed to the surgeon, for example to ensure that the module10has been securely attached to the correct surgical device. Where the module10is determined not to have been attached to the correct surgical device, the module10can alert the surgeon to the error, for example by displaying an error message on the display50. In some embodiments, where the identification information includes an angular offset of a portion of the surgical device from the module10when the surgical device is attached to the module10, the identification information can be used to calculate an absolute position and/or orientation of that portion of the surgical device. Additionally or alternatively, the identification information, e.g., a type of the surgical device, can cause the module10to detect and/or calculate different types of positional information. By way of non-limiting example, the module10can be configured to switch into the full detection mode when the engagement features40detect that the module10is connected to a surgical instrument that is intended to change position and orientation during surgery, and into the orientation detection mode when the engagement features40detect that the module10is connected to a surgical device, e.g., an implant, that is only or primarily intended to change orientation during the surgery. In still further embodiments, where the module10is in communication with an external display that provides a graphical depiction of the surgery in real-time based on positional information transmitted from the module10, the external display can use the identification information to incorporate an illustration of the surgical device to which the module10is attached in the graphical depiction. The identification information can be stored along with positional information collected and/or calculated by the module10during surgery, e.g., to facilitate later reconstruction of the surgery.

The surgical electronic modules disclosed herein can generally be used to detect a position and/or orientation of a surgical device to which they are attached as well as changes in said position and/or orientation. Where the surgical device is also attached to a portion of a patient's anatomy, the surgical electronic module can be used to detect a position and/or orientation of that portion of the patient's anatomy as well as changes in said position and/or orientation. In an exemplary embodiment, two surgical electronic modules can be attached to two pedicle screws to detect an amount of correction in a patient's spinal curvature during a pedicle subtraction osteotomy.

The steps of an exemplary pedicle subtraction osteotomy utilizing the module10and a second module10a, which can be identical to the module10, are illustrated inFIGS. 4-6. However, it will be appreciated by a person skilled in the art that any surgical electronic module as described herein can be used, either the same or different from one another, and that the modules10,10acan be used in a variety of surgical procedures that effect changes in anatomical position and/or orientation. Further, it will be appreciated that the calculations said to be performed by the modules10,10acan either be performed by both of the processors22,22aor by only one of the processors22,22a. Where the below-described calculations are performed by both of the processors22,22a, the modules10,10acan communicate the results of the calculations with one another to check for accuracy and can display an error message to the user when there is a mismatch. The calculations can also be performed by a remote base station configured to receive positional information from the modules10,10a.

As shown inFIG. 4, prior to the exemplary osteotomy procedure, the patient's lumbar spine includes a kyphotic deformity in which a first vertebra V1is positioned at an angle α in the sagittal plane relative to a second vertebra V2. A purpose of the osteotomy procedure can be to reduce the angle α to a desired value, e.g., by removing a corresponding amount of bone from a vertebra disposed between the vertebrae V1, V2. The amount of angular correction can be determined based on pre-operative imaging and calculations. In some embodiments, prior to surgery, the modules10,10acan be calibrated to one another to thereby synchronize their coordinate systems. For example, the modules10,10acan be mechanically connected to one another via, e.g., the engagement features40,40a, and rotated through space as a pair until sufficient information has been gathered to synchronize their coordinate systems. An output signal can be provided to the user, for example a visual signal on the display50, a vibration, and/or an audio signal, to indicate when synchronization has been completed. Such synchronization can facilitate automated error correction, e.g., for axial rotations, and/or can facilitate quantification of coronal plane changes.

First and second pedicle screws70,70acan be implanted into first and second pedicles P1and P2of first and second vertebrae V1and V2, as shown inFIG. 5, according to customary surgical procedures. The first module10can be rigidly attached to the first pedicle screw70and the second module10acan be rigidly attached to the second pedicle screw70avia the engagement features40,40aof the first and second modules10,10a. The modules10,10acan be attached to the pedicle screws70,70aeither before or after the pedicle screws are implanted. Through this series of connections, changes in the positions and/or orientations of the first and second modules10,10acan correspond to changes in positions and/or orientations of the first and second pedicle screws70,70a, respectively, and to changes in positions and/or orientations of the first and second pedicles P1, P2to which the pedicle screws70,70aare attached.

Once the modules10,10ahave been attached to the screws70,70aand the screws70,70ahave been implanted in the pedicles P1, P2in an initial position and/or orientation, the modules can be powered up and the zeroing buttons60,60acan be actuated to indicate to the modules10,10athat the modules10,10aare in the initial position and/or orientation. Thus, as shown inFIG. 5, the displays50,50acan each display “0” to indicate that the modules10,10aare oriented at an initial angle relative to one another. As the procedure is performed, the sensors28,28aof the modules10,10acan detect absolute azimuth and polar angles θ, φ of each of the modules10,10awith respect to the earth. The modules10,10acan communicate their absolute azimuth and polar angles θ, φ to one other via the communications interfaces26,26a. Given this information, the processors22,22acan then calculate a relative angle β of the first module10with respect to the second module10ain the sagittal plane (e.g., by subtracting the absolute angles measured by the modules). The relative angle β at the initial position and/or orientation of the modules10,10acan be stored in the memories24,24a.

Angular correction of the spine along the sagittal plane can then be performed according to customary surgical procedures, which can include removal of bone between the first and second vertebrae V1, V2at an osteotomy site O of a vertebra disposed between the vertebrae V1, V2. During the correction, the sensors28,28acan continually detect the absolute azimuth and polar angles θ, φ of the modules10,10aand the processors22,22acan continually calculate the relative angle β based on the updated azimuth and polar angles θ, φ. As the relative angle β changes during the surgery, the processors22,22acan further calculate a change Δβ in the relative angle β over a specified period of time. In the illustrated embodiment, where the modules10,10awere zeroed at the initial position and/or orientation, the change Δβ in the relative angle β between the initial angle and the current angle (and thus the amount of correction achieved) can be displayed on the displays50,50a. In this way, the user can be provided with a real-time, quantitative measurement of angular correction throughout the surgery. When the desired angular correction has been achieved (FIG. 6), as indicated for example by the value of Δβ displayed on the displays50,50a, the patient's spine can be stabilized in the corrected position and/or orientation.

In some embodiments, the processors22,22acan further calculate derivatives of values detected by the sensors28,28aand/or calculated by the processors22,22a, such as β, θ, and φ. By way of non-limiting example, the processors22,22acan calculate a first derivative of β, i.e., a rate of change Δβ/Δt in the relative angle β over time, a second derivative of β, i.e., a relative acceleration Δβ/Δt2, and/or a third derivative of β, i.e., a relative jerk Δβ/Δt3of the modules10,10aThe rates of change Δβ/Δt, Δθ/Δt and/or Δφ/Δt can be useful for error checking, for example to indicate whether the patient has been accidentally moved during the procedure. For example, in embodiments where the processors22,22acalculate a rate of change Δθ/Δt for each of the modules10,10a, it can be assumed that the patient is moving when the rate of change Δθ/Δt of the first module10is equal to the rate of change Δθ/Δt of the second module10a, since it is unlikely that the first and second modules10,10awould be moved at precisely the same rate as part of the surgical procedure. Thus, when the rate of change Δθ/Δt of the first module10is equal, or at least substantially equal, to the rate of change Δθ/Δt of the second module10a, either or both modules10,10acan alert the surgeon to the patient's movement, for example by displaying an error message on the displays50,50a. Additionally or alternatively, to provide clinical feedback, the rates of change Δβ/Δt, Δθ/Δt and/or Δφ/Δt can be displayed, e.g., on the displays50,50a, and/or stored, e.g., in the memories24,24a. Information about the rates of change Δβ/Δt, Δθ/Δt and/or Δφ/Δt can be useful for clinicians because they provide a measure of how quickly an anatomical adjustment is made, which may correlate to patient outcomes.

In some embodiments, spinal fixation or stabilization hardware (e.g., screws and rods) can be coupled to a first side of the patient's spine before correction is performed without locking down the fixation hardware. The modules can be coupled to screws implanted in a second, contralateral side of the patient's spine. After the desired amount of correction is achieved, the fixation hardware in the first side of the patient's spine can be locked down to maintain the corrected angle. The modules can then be removed and a spinal fixation element80can be attached to the pedicle screws70,70aimplanted in the second, contralateral side to complete the fixation. In other embodiments, spinal fixation or stabilization hardware can be coupled only to a single side of the patient's spine, e.g., a side on which the modules10,10aare attached. It will be appreciated that the modules10,10acan be removed from the pedicle screws70,70aeither before or after a spinal fixation element or rod80is coupled to the pedicle screws.

The above-described method involves a single level osteotomy and first and second modules10,10aconfigured to measure a local correction, however it will be appreciated that more complex deformity correction can also be performed. For example, rotational deformities or angular deformities in any of the sagittal, axial, and/or coronal planes can be corrected and the degree of correction monitored using the modules disclosed herein. By way of further example, several modules (e.g., three, four, five, six, seven, eight, or more) can be coupled to corresponding vertebrae to provide correction measurements for a spinal segment (e.g., a lumbar region, a thoracic region, a cervical region, etc.) or for an entire spine (e.g., from skull to tailbone). Measurement data associated with such procedures can be communicated to an external display to give the surgeon a graphical depiction of overall spinal correction.

Although not shown, additional information can be displayed on the displays50,50aand/or on an external display in communication with the modules10,10a. The information displayed on the display50can be selected by a user before the procedure, can be impacted by the surgical device to which the module10is attached, and/or can be preconfigured as part of the factory settings of the module10. By way of non-limiting example, the modules10,10acan convey positive and/or negative feedback to the surgeon during surgery. For example, the displays50,50acan convey an error message to the user when the change Δβ in the relative angle θ exceeds the desired angular correction, when the engagement features40,40adetect that they are not attached to the correct surgical device, and/or when engagement between the engagement features40,40aand the pedicle screws70,70ahas been lost or weakened. In some embodiments, where the processors22,22aare configured to calculate the rate of change Δβ/Δt in the relative angle β, the displays50,50acan convey an error message to the user when the rate exceeds a predetermined speed limit. In still further embodiments, should the patient be rotated in the axial plane during the surgery, for example due to a table rotation or rolling over of the patient, one or both of the modules10,10acan detect the change and can be configured to alert the surgeon via an error message on the displays50,50a, which may include an instruction to recalibrate. In case of a need to recalibrate, the modules10,10acan be detached from the screws70,70aand can be attached to one another to repeat the calibration procedure described above.

Information detected and/or calculated by the modules10,10aduring the procedure can be collected and stored for later use. The information can be stored locally in the memories24,24aand/or can be transmitted via the communications interfaces26,26ato one or more external base stations. The stored information can be used at a later time for various purposes, for example to create a reproduction of the surgery, for clinical improvement, research, and/or ethnography.

Another exemplary pedicle subtraction osteotomy using one or more surgical electronic modules as described herein is illustrated inFIGS. 7 and 8. The procedure according to this method involves the use of four surgical electronic modules10b,10c,10d,10e, which can detect, calculate, store, and/or transmit information in a similar manner to the modules10,10adescribed above during the exemplary pedicle subtraction osteotomy ofFIGS. 4-6. It will be appreciated by a person skilled in the art that any surgical electronic module as described herein can be used, either the same or different from one another, and that the modules10b,10c,10d,10ecan be used in a variety of surgical procedures that effect changes in anatomical position and/or orientation.

Similarly to the procedure described with reference toFIGS. 4-6, a desired angular correction of the spine can be determined prior to the surgery. The modules10b,10c,10d,10ecan be calibrated by freely rotating mated pairs of the modules10b,10c,10d,10euntil enough positional information has been acquired to synchronize their coordinate systems. For example, the module10bcan be attached to each of the other modules10c,10d,10e, and synchronized with each of the other modules10c,10d,10eto ensure that all of the modules10b,10c,10d,10eare synchronized to each other.

The first three modules10b,10c,10dcan be rigidly attached to three pedicle screws70b,70c, and70d, while the fourth module10dcan be rigidly attached to a surgical cutting instrument such as a rongeur90. The engagement features40b,40c,40d,40ecan detect an identity of the device to which the modules10b,10c,10d,10eare attached, such that the first three modules10b,10c,10dcan detect that they are each attached to a pedicle screw and the fourth module10ecan detect that it is attached to a rongeur. Based on this information, the first three modules10b,10c,10dcan switch into the orientation detection mode in which only orientation information is displayed to the user, and the fourth module10ecan switch into the full detection mode in which orientation and position information is displayed. Further, as explained in detail below, the processors22b,22c,22dof the first three modules10b,10c,10dcan be configured to calculate different positional information from the processor22eof the fourth module10e. It will be appreciated by a person skilled in the art, however, that the procedure can be performed utilizing only three modules, two of which are attached to two pedicle screws and the third of which is attached to a surgical cutting instrument.

The pedicle screws70b,70c,70dcan be implanted into pedicles P1, P2, and P3on vertebrae V1, V2, and V3, either before or after the modules10b,10c,10dare attached thereto. At least one of the pedicle screws70b,70c,70dcan be implanted on an opposite side of an intended osteotomy site O from at least one of the other pedicle screws70b,70c,70d. Similarly to the modules10,10aused in the exemplary procedure ofFIGS. 4-6, an initial position and/or orientation of the modules10b,10c,10dwith respect to one another can be set by actuating the zeroing buttons60b,60c,60d. Thus, as shown inFIG. 7, the displays50b,50c,50dcan each display “0” to indicate that the modules10b,10c,10dare oriented at an initial angle relative to one another. Angular correction of the spine along the sagittal plane can then be performed according to customary surgical procedures, which can include removal of bone from a vertebra disposed between the second and third vertebrae V2, V3by the rongeur90. During the procedure, the sensors22b,22c,22dcan continually detect absolute azimuth and polar angles θ, y of each of the modules10b,10c,10d. The modules10b,10c,10dcan communicate their absolute azimuth and polar angles θ, φ with each other (e.g., via Bluetooth or other wired or wireless communication) to thereby allow for the processors22b,22c,22dto calculate a relative angle β1of the first module10bwith respect to the second module10c, a relative angle β2of the second module10cwith respect to the third module10d, and a relative angle β3of the first module10bwith respect to the third module10d. Further, the modules10b,10c,10dcan calculate changes Δβ1, Δβ2, Δβ3in the relative angles β1, β2, β3throughout the procedure, rates of changes Δβ1/Δt, Δβ2/Δt, Δβ3/Δt, and/or rates of changes Δθ/Δt, Δφ/Δt in the azimuth and polar angles θ, φ of each of the modules10b,10c,10d.

Because the relative angle β1of the modules10b,10cwith respect to one another does not change throughout the procedure since the modules10b,10care on the same side of the osteotomy site O, the modules10b,10c,10dcan be configured to display only Δβ2. The displays50b,50c,50dcan be configured not to display the change Δβ1since it will remain substantially equal to zero throughout the procedure, and not to display the change Δβ3because Δβ2and Δβ3will remain substantially equal to one another throughout the procedure. Of course, it will be appreciated by a person of skill in the art that the modules10b,10c,10dcould display either Δβ2and Δβ3, since they are substantially equal to one another, and Δβ2has been chosen solely for purposes of illustration. Also, if at any point during the surgery, Δβ1ceases to be substantially equal to zero and/or Δβ2and Δβ3cease to be substantially equal to one another, all three relative angular changes Δβ1, Δβ2, Δβ3can be displayed on the displays50b,50c,50d. Any of these values can be displayed on an external display alternatively or in addition.

The module10ecan be attached to the rongeur90via engagement features40eon the module10eat any point during the surgery to help the surgeon remove a desired amount of bone from a desired location. Like the modules10b,10c,10d, the module10ecan be “zeroed” by user actuation of the zeroing button60ewhen the module10eis placed in an initial position and/or orientation, e.g., when the rongeur90to which the module10eis coupled is inserted at a desired cutting angle and at a maximum desired cutting depth into the patient's body. Thus, as shown inFIG. 7, the module10ecan display two zeros, one indicating an initial angle and one indicating an initial distance. Preferably, the module10eis zeroed before any angular correction in the patient's spine has been achieved and/or at the same time that the other modules10b,10c,10dare zeroed.

Because the module10eis able to detect that it is attached to a surgical instrument, e.g., the rongeur90, as opposed to a surgical implant, e.g., the pedicle screws70b,70c,70d, it can be configured to calculate and/or display different positional information than the modules10b,10c,10d. This information can supplement the information displayed by the modules10b,10c,10dto confirm that a desired angular correction has been achieved. In particular, whereas the modules10b,10c,10dare configured to calculate and/or display changes in positional information with respect to one another, the module10ecan be configured to calculate and/or display changes in its own positional information throughout the surgery. Further, whereas the modules10b,10c,10dare configured to calculate and/or display changes in their relative orientations, the module10ecan be configured to calculate and/or display changes in both orientation and position.

To perform these calculations, the module10ecan continually detect absolute azimuth and polar angles θ, φ of the module10ewith the sensor28e, calculate an absolute angle β4of the module10ein the sagittal plane with the processor22e, and store the absolute angle β4for any given time in the memory24e. Similarly, the sensor28ecan continually detect an absolute position (e.g., including a distance d4of the module10erelative to a starting position) via triangulation, time-of-flight, or other positioning algorithms using ultrasonic, electromagnetic, and/or infrared location signals sent by each of the modules10b,10c,10d,10eand communicated therebetween. It will be appreciated by a person skilled in the art that, where at least three modules are used, unique position information can be created through location signals sent out by each of the modules and communication among all of the modules of the information received from the signals while the modules10b,10c,10dare stationary, e.g., before they are moved together as part of reduction procedure. It will further be appreciated by a person skilled in the art that the position of the rongeur90can be determined through communication between the module10eand other surgical electronic modules positioned in the operating room. As the position and/or orientation of the rongeur90changes during surgery, the processor22ecan calculate and the display50ecan display a change Δβ4in the angle β4and/or a change Δd4in the distance d4of the module10e—and therefore of the rongeur90—in the sagittal plane. For example, as shown inFIG. 8, the display50ecan indicate that the rongeur90has moved by a distance of 49 mm and by an angle of 27 degrees from the initial position and orientation. In this way, the surgeon can know when the rongeur90has completed a desired motion to thereby remove a desired amount of bone. In some embodiments, the module10ecan be configured to alert the surgeon when the rongeur90is moved outside of or beyond a surgical plane, e.g., beyond a desired angle and/or distance, for example by displaying an error message on the display50and/or providing an audio signal or vibration. For example, the surgeon can be warned when the distal end of the rongeur is approaching or has exceeded a predetermined maximum insertion depth in the anterior direction (e.g., when the axial displacement of the rongeur relative to the starting position approaches zero or becomes negative).

Similarly to the exemplary pedicle subtraction osteotomy ofFIGS. 4-6, when the desired angular correction of the spine in the sagittal plane has been achieved, the change Δβ2in the relative angle β2displayed on the displays50b,50c,50dwill be equal to the desired angular correction. The patient's spine can then be stabilized in the corrected position via a spinal fixation element80that can be attached to the implanted pedicle screws70b,70c,70d. The modules10b,10c,10dcan be removed from the pedicle screws70b,70c,70dand the module10ecan be removed from the rongeur90either before or after fixation with the spinal fixation element80.

It will be appreciated by a person skilled in the art that a greater number of modules can enhance the accuracy of the procedure by providing for a greater amount of positional information. For example, using more modules can provide positional information to a greater degree of precision and/or specificity, e.g., with more significant digits, which can be displayed to the surgeon. As each module is added in the procedure, the number of significant digits displayed to the surgeon can increase, thereby providing a measure of the increase in accuracy added by each additional module to the surgeon. Additionally or alternatively, using a greater number of modules can enable the modules to detect and/or calculate their positions and/or orientations in more dimensions. The positions, orientations and/or changes in the positions and/or orientations of the modules can be displayed to the user for each plane in which information is acquired. However, it will also be appreciated by a person of skill in the art that a position and/or an orientation of the module in certain planes need not be calculated since it can be assumed that the patient will not move in certain planes.

It will further be appreciated by a person skilled in the art that the devices and methods described herein can be particularly useful for robotic assisted surgery. For example, one or more surgical electronic modules as described herein can transmit positional information to a robotic manipulator, which can manipulate the one or more modules until they have reached a desired final position that has been input to the manipulator.

Further embodiments of devices and methods for intraoperatively measuring position or angular orientation are also provided. In one embodiment, measuring simultaneous angles in multiple orthogonal planes can be accomplished using a single device that includes an integrated display. Such a device can be permanently assembled to medical tools and instruments in some embodiments, while in other embodiments it can be modular to allow for use with a number of medical tools and instruments during surgery. A 9-axis inertial motion unit (IMU) or sensor consisting of a 3-axis accelerometer, a 3-axis gyroscope, and a magnetometer can be housed inside the device to allow angular measurements. In another embodiment, a 3-axis accelerometer alone can be used to allow angular measurement between orthogonal planes. In other embodiments, any of a variety of other sensors can be employed that can provide information related to the position and/or orientation of the sensor.

FIGS. 9A and 9Billustrate one embodiment of such a device100that is integrally formed with an electronic module102for detecting position or orientation information during use. The module102can include a housing104containing a sensor (not shown), a processor (not shown), and a display106for communicating information to a user. The device100can also include an input for receiving instruction from a user. In the illustrated embodiment, the input can be a single button108, though in other embodiments different inputs, such as toggles, switches, a plurality of buttons, etc. can be utilized. For example, and as shown inFIGS. 9A-12, the button108can allow a user to zero and successively complete angular measurement. By way of further example, a single press of the button108can calibrate the sensor to initialize or zero the angular measurement at a desired starting location (seeFIG. 10left side, referred to as “State A”). This can be represented by a thin box110around the 0° displays, as shown inFIG. 10. A second press of the button108at a new location can define a desired plane between the starting and the new location. The instrument100can provide angular measurement between these locations in two planes, i.e., the newly defined plane112and the plane114that is orthogonal to the defined plane but still parallel to the gravitational field (seeFIG. 10right side, referred to as “State B”).

In another embodiment, a device120can provide for defining a projection plane, parallel to a gravitational field, between two locations by using, for example, two depressions of a button or other input. For example, a user can press a button122once at a starting location (labeled State A and passing through point A inFIGS. 11A and 11B) and press the button a second time at a second, new location (labeled as State B and passing through point B inFIGS. 11A and 11B). This can allow for defining a desired projection plane (Plane X inFIGS. 11A-12) for angular measurement. Depression of the button122, for example third and fourth times, can allow angular measurements between any other two locations. Measurements between these locations can be displayed as projected angles in the newly defined projection plane (Plane X inFIGS. 11A-12) and a plane orthogonal to the defined projection plane (Plane Y inFIGS. 11A-12).

By way of further example,FIG. 11Aillustrates the measurement of an angle θ in labeled Plane X between a first position of the instrument120at labeled State A and a second position of the instrument at labeled State B.FIG. 11Billustrates an orthogonal section view and the measurement of an angle ϕ in labeled Plane Y (which is orthogonal to Plane X inFIG. 11A) between the first position of the instrument120at labeled State A and the second position of the instrument at labeled State B.FIG. 12illustrates the labeled planes X and Y from a top view, showing their orthogonal relationship to one another.

FIG. 12also illustrates a top view the instrument122showing a reference plane alignment feature124to aid a user in defining orthogonal projection planes relative to a patient126. The reference plane alignment feature124can be, for example, a ridge, depression, line, or other marking that a user can reference to align the instrument122with a desired reference or projection plane. In the illustrated embodiment, for example, the instrument is positioned such that the reference plane alignment feature122is aligned with the projection plane labeled Plane X. The projection plane labeled Plane Y is established based on Plane X without need for a dedicated reference feature on the instrument122. In some embodiments, however, a secondary marking or feature could be included to explicitly denote the orientation of the orthogonal projection or reference plane.

The devices and methods described herein, including the sensors used to detect changes in position or orientation, can be utilized in connection with a number of surgical instruments. In one embodiment, for example, sensors can be attached to an osteotome or chisel for accurate bone cutting to create a desired wedge during a pedicle subtraction osteotomy to achieve planned sagittal balance. During cutting these osteotomies, surgeons often want to know both the angle for the wedge and also the angle of attack in the orthogonal plane. In some cases, surgeons cut osteotomies in a medial to lateral direction at a certain angle to avoid any unintended damage to the critical anatomy in case of slips and overcuts.

The devices and methods described herein can also allow surgeons to create asymmetric wedges at each level for complex deformity correction procedures that require correction of sagittal and coronal balance. Prior techniques often include in-vivo use of many cobbled together methods, including a combination of “eyeballing,” experience, estimation, multiple fluoro images or the use of templates, wedges, and rasps to estimate bone removal work. Utilizing the devices and methods described herein can provide a number of advantages over these prior techniques. Furthermore, the devices and methods can be applied to other osteotomies performed in trauma, joints, and CMF (craniomaxillofacial) procedures.

For example, there is currently no quick way to measure sagittal balance and regional curves intraoperatively during deformity and degenerative surgeries. Prior techniques often involve taking fluoro-images, sending them to a PACs (Picture Archiving and Communication) system, and using the images to measure correction with a manual protractor. Such a technique can require a surgeon to leave a sterile field, which is not desirable and increases surgery time. In one embodiment, a device according to the teachings provided herein can be coupled to any medical device, tool, or instrument that can be aligned with two endplates at the apex of a desired curve by means of fluoro-images to measure desired lordosis or kyphosis plus scoliosis angles simultaneously.

In another embodiment, a sensor can be coupled to a deformity correction instrument, such as quick-sticks, towers, frames, or flex-clips, during derotation and axial correction of the spine. Surgeons can attach sensors to these instruments before starting the correction or maneuvers in some embodiments. During this time, a surgeon can decide to zero the sensors and, after final correction, the sensors can provide more information on the angular correction achieved in the axial and sagittal planes.

In still another embodiment, a surgeon can attach one or more sensors to Lenke probes, gearshifts, awls, drills, or taps that can assist surgeons to achieved planned pedicle screw trajectory or pedicle preparation trajectory. The devices and methods described herein can also be used to train surgeons to place mPACT (medialized Posterior Approach Cortical Trajectory) cortical screws, iliac screws and SAI (Sacral-Alar-Iliac) screws using an optimized trajectory.

Furthermore, a surgeon can use the devices described herein to measure and register an angle used to place a pedicle screw on one side of the vertebrae, and then use this registered information to mirror a pedicle screw trajectory on other side. This can allow surgeons to have pedicle screws inserted symmetrically across the spine, which can further allow similar bent rods to be placed on each side. Rod bending is a highly cumbersome and skilled art, using similar bent rods on each side of a patient's spine can save significant time.

The embodiments described above and illustrated in 9A-12 include a single sensor and a one-button interface. In other embodiments, a device can include, for example, a different number of buttons for an input or interface. By way of further example, a single sensor device can include a four-button interface, as described below and illustrated inFIGS. 13A-16. The number of buttons can be varied, however, based on desired workflow and/or usability. For example, short and long presses of one or more buttons can be utilized to provide functionality equivalent to other embodiments in which a larger number of buttons are included.

The embodiment described below can be utilized for measuring anatomical, instrumental, or device based change in position or angular orientation. In this embodiment, systems quantitatively measure changes in the position or angular orientation of a portion of a patient's anatomy or a medical device with respect to another portion of the patient's anatomy or a medical device during surgery. The devices and methods described herein can be utilized to achieve the same functionality described above and in U.S. application Ser. No. 14/471,120, entitled “SYSTEMS AND METHODS FOR INTRAOPERATIVELY MEASURING ANATOMICAL ORIENTATION,” filed Aug. 28, 2014, the entire contents of which are hereby incorporated by reference. One advantage of the embodiments described herein, however, is that this functionality can be achieved with a single sensor housed in a medical device.

As shown inFIGS. 13A and 13B, a device130can include an electronic module132permanently assembled to a medical tool and/or instrument134in one embodiment. In another embodiment, the module132can be modular to allow for use with number of medical tools and instruments during a surgery. As noted above, a 9-axis inertial motion unit (IMU) or sensor that can include a 3-axis accelerometer, a 3-axis gyroscope, and a magnetometer, can be housed inside the device to provide angular measurements. In another embodiment, a 3-axis accelerometer alone can be used to provide angular measurement between orthogonal planes.

Operation of devices, such as the device130, illustrated in 13A-16 is described below. The device130can include an input136that, in the illustrated embodiment, includes four buttons136a,136b,136c,136dthat can allow a user to provide instruction regarding measurement of a change in position or angle. Further, a display138can communicate measured or calculated position or orientation data back to a user during use.

As shown inFIG. 14A(and referred to as “State A”), a first button136acan be initially lit to indicate to a user that this button should be pressed for a next action. Pressing the first button136acan allow a user to zero and calibrate the sensor in a first starting position. The display can display one or more zeros140to denote positioning of the instrument at a starting position/orientation. For example, inFIG. 15Athe instrument130is attached to the screw A in the starting position.

FIG. 14B(referred to as “State B”) illustrates a second button136bthat lights to indicate to a user to press this button for a next action. Prior to pressing the second button136b, the instrument130can be moved to a new end point location. For example, inFIG. 15Athe instrument is attached to the screw B in the new end point location. Pressing the second button136bcan allow the user to measure an angle between a start point location and this new end point location in two orthogonal planes (e.g., angles θ1and ϕ1in planes X and Y, respectively, as shown inFIGS. 15A and 15B). The top-left of the display138can be updated with the measured angle142at the end point location (e.g., when the instrument130is attached to the screw B inFIG. 15A).

FIG. 14C(referred to as “State C”) illustrates a third button136cthat can be illuminated to indicate to a user to press this button for a next action. When a user has gone through an osteotomy closure during deformity correction, for example, they can take the sensor to the previous start point location (e.g., the position where the device130is in contact with the screw A shown inFIG. 15C). The third button can be pressed to zero the sensor at this location, as reflected by the display of 0° (ref. no.144) in the upper right corner of the display138.

The user can then move the sensor to the end point location (e.g., the position where the device130is in contact with screw B shown inFIG. 15C). A fourth button136dcan be lit indicating that the surgeon or other user can press it for a next action. Upon pressing the button136d, as shown inFIG. 14D(referred to as “State D”), the top-right corner of the display138can be updated with a new measured angle146between the new start and end points in two orthogonal planes (e.g., angles θ2and ϕ2in planes X and Y, respectively, as shown inFIGS. 15C and 15D). Furthermore, a first delta (e.g., θ1−θ2)148in the defined plane (Plane X) and a second delta (ϕ1−ϕ2)150in the orthogonal plane (Plane Y) can be updated indicating changes in the angular orientation of the original location (an initial location of a patient's anatomy, medical device, or implant before correction) with respect to the new locations (a final location of a patient's anatomy, medical device, or implant after correction).

In some embodiments, pressing any two buttons (e.g.,136c,136d, etc.) together can instruct the system to reset all values and ready the device130for a new differential angular measurement, as shown inFIG. 14E(referred to as “State E”).

In another embodiment, the device can allow for defining a projection plane, parallel to a gravitational field, between two locations with two depressions of a fifth button positioned at the center of the four buttons. Differential Measurements between any new locations can be displayed as projected angles in this newly defined projection plane (Plane X inFIGS. 15A-16) and a plane orthogonal to this defined projection plane (Plane Y inFIGS. 15A-16). For angular measurements, a similar workflow as outlined above for States A through E above can be used.

As noted above,FIGS. 15A-15Dillustrate one example of how a device130with a four-button input or interface can be utilized to measure changes in position or orientation simultaneously in two orthogonal planes. As shown in the orthogonal section views ofFIGS. 15A and 15B, the device130can be zeroed when in a first position where it is in contact with screw A by pressing the first button136a. The device can then be moved to a second position where it is in contact with screw B and the second button136bcan be depressed. This can record the angle θ1in the Plane X between the first and second positions, as well as the angle ϕ1between the first and second positions in the Plane Y (that is orthogonal to the Plane X).

Following surgical manipulation of the patient's anatomy152, a second set of measurements can be made using the device130. As shown inFIGS. 15C and 15D, the device130can be zeroed when in the first position where it is in contact with screw A by pressing the third button136c. The device can then be moved to the second position where it is in contact with screw B and the fourth button136dcan be depressed. This can record the angle β2in the Plane X between the first and second positions, as well as the angle φ2between the first and second positions in the Plane Y (that is orthogonal to the Plane X).

The display138of the device130can communicate measured and calculated position or orientation data to a user. As shown inFIG. 15C, for example, the display138can include the angles θ1and ϕ1in an upper left corner154, the angles θ2and ϕ2in an upper right corner156, the delta θ1−θ2in the center158, and the delta ϕ1−ϕ2in the lower right corner160. The positioning of the information on the display138can be different in alternative embodiments, and any of a variety of types of information in different display formats can be communicated to a user.

FIG. 16illustrates the instrument130from a top view and highlights that the instrument can include a reference plane alignment feature162to aid a user in defining the reference plane (Plane X in the figure) and the orthogonal plane (Plane Y in the figure). In the illustrated embodiment, a flat surface on a side of the instrument130can serve as the reference plane alignment feature that can be oriented parallel to the reference plane (Plane X). In other embodiments, a marking, recess, protrusion, or other feature can be utilized, as described above. Further, in some embodiments an additional marking or feature can be included to denote the orientation of the orthogonal plane (Plane Y in the figure).

The above-described embodiments can have a number of advantages over prior devices and techniques. For example, the devices and methods described herein can provide an instrument for intraoperatively measuring anatomical orientation that can be easy to use and can be independent of a wirelessly (e.g., Wi-Fi®, Bluetooth®, etc.) or otherwise remotely-connected tablet or display. Moreover, there is currently no quick way to measure sagittal balance and regional curves intraoperatively during deformity and degenerative surgeries. Many prior techniques involve taking fluoro-images, sending them to a PACs (Picture Archiving and Communication) system, and using the images to measure correction using a manual protractor. This type of technique can require a surgeon to leave a sterile field, which is not desirable and can increase surgery time. In one embodiment, a device according to the teachings provided herein can be coupled to any medical device, tool, or instrument that can be aligned with two endplates at the apex of the desired curves by means of fluoro-images to measure starting lordosis or kyphosis plus scoliosis angles simultaneously as soon as patient is placed on the operating table. This can be advantageous because placing a patient prone on a table can change their regional curve. Surgeons are often interested in knowing this angle and registering it as reference starting point. All further corrections and improvements in sagittal balance, as well as subsequent changes in regional angular values, can be measured relative to this reference point using, for example, the third and fourth buttons136c,136dof the device described above. For example, the steps shown inFIGS. 14C, 14D, 15C, and 15Dcan be repeated as a surgeon or other user manipulates a patient's anatomy and measurements can be taken relative to the original starting positions recorded as shown inFIGS. 14A, 14B, 15A, and 15B.

The above described devices and methods can be utilized for a number of different procedures, including, for example, as a tool for measuring angular orientation of a portion of a patient's anatomy, an osteotome with angular orientation sensing capability, a tool for pedicle targeting, and a tool for rod bending, among others. These devices can provide surgeons with an ability to intraoperatively measure spinal correction achieved at each regional curve, including lordosis, kyphosis, and scoliosis. Further, devices and methods described herein can provide an association between correction achieved in a standing and a prone position, as well as an ability to provide coronal correction measurement. Such methods and devices can aid surgeons in achieving coronal alignment, shoulder and pelvic leveling during complex deformity correction procedures, and can provide degeneration and minimally invasive procedure surgeons with tools to intraoperatively monitor spinal alignment.

The devices and methods described herein can provide such functionality while minimizing sensor size and reducing visual obstruction to a surgeon. This can provide surgeons with real-time regional curve and osteotomy closure angle measurement without compromising workflow or visualization. Furthermore, the devices described herein can make use of wired or wireless components (e.g., wired components can in some cases be made smaller than wireless components, further reducing the size of a device). The methods described herein can provide quick, simple to use, low profile, and easy to connect components that can be used with a surgeon's existing tools. This can allow surgeons to quickly validate angles utilizing their existing instrumentation to achieve consistent surgical outcomes. Further, the devices described herein can include a variety of user interfaces, including a digital display, a single button, four buttons, five buttons, or another configuration. The devices described herein can be configured to couple to bone cutting tools, taps, Lenke probes, osteotomy closure clamps, harmonic tools, or rod benders. The devices and methods described herein could also be configured for use with lordotic cages to confirm achievement of proper angular correction at a particular level.

Moreover, the devices described herein can be incorporated into a modular handle that can be moved between various surgical instruments. This can allow the devices and methods described herein to be utilized in connection with other deformity, degenerative, and minimally invasive surgery (MIS) applications.

Exemplary features of the devices and methods described herein can include a disposable integrated handle with an angle sensor, a built-in display, and a low profile easy to connect feature for mating with existing surgical instruments. Such a device can allow a surgeon to intraoperatively measure actual regional angles after aligning a tool with respective end plates, or measure a change in angles projected on to any two orthogonal planes. A free-hand tool according to the teachings provided herein can be used to validate osteotomy wedge angles, enable accurate bone removal (as in osteotomies), target trajectory for pedicle screws, mirror trajectory for pedicle screws, and bend spinal rods.

Further illustration of embodiments of the devices and methods described herein is shown inFIGS. 17A-22B.FIGS. 17A-17G, for example, illustrate one embodiment of a method of operation of an instrument for intraoperatively measuring anatomical orientation having a three-button input interface.FIG. 17A, for example, illustrates coupling of an electronic module170to an instrument172and positioning of the instrument170such that it is in contact with a pedicle screw or other rigid bony attachment173that can be implanted in, for example, a patient's spine174. The module170can include a display176, an input178including three buttons178a,178b,178c, and a reference plane alignment feature180. In the illustrated step of the method, the instrument172with electronic module170coupled thereto can be positioned at a first point in contact with the pedicle screw173or a portion of the patient's anatomy and the reference plane alignment feature180can be aligned with the desired reference plane (e.g., a patient's sagittal plane) into which measured angles can be projected. The first button178a, which can be illuminated to prompt a user in connection with, for example, a prompt on the display176, can be depressed to record the current position and/or orientation and define the reference plane.

FIG. 17Billustrates another step in which the instrument is moved to a first position and the second button178b(which can be illuminated to prompt a user after the first button178ais depressed to define the reference plane) can be depressed to record the current position and/or orientation at the first position. In another step illustrated inFIG. 17C, the instrument172can be moved to a second position and the third button178c(which can be illuminated to prompt a user after the second button178bis depressed to define the first position) can be depressed to record the current position and/or orientation at the second position. A processor included in the electronic module170can then calculate angular differences between the position or orientation of the instrument172in the first and second positions, as projected onto the reference plane and a plane orthogonal thereto. This measurement can serve as a baseline or pre-manipulation reference.

Following surgical manipulation of the patient's anatomy (e.g., spine174), the measurement process can be repeated as shown inFIGS. 17D-17F. In particular, the reference plane can be redefined using the first button178a, as shown inFIG. 17D. In addition, position and/or orientation information can be captured at the first position using the second button178b, as shown inFIG. 17E, and position and/or orientation information can be captured at the second position using the third button176c, as shown inFIG. 17F. The processor of the module170can then communicate measured and calculated information to a user via the display176, including a first angle184measured between the first and second positions before surgical manipulation and a second angle186measured between the first and second positions after surgical manipulation, as well as a delta188between those angles, as shown inFIG. 17G. These angles can be projected into the defined reference plane182and a further angle190can be included representing change in a plane orthogonal to the reference plane182.

FIGS. 18A-18Jillustrate another embodiment of a method of operation of an instrument for intraoperatively measuring anatomical orientation having a three-button interface. The method is similar to the method described above and shown inFIGS. 17A-17G, but illustrates additional features that can be provided in various embodiments. For example,FIGS. 18A-18Cillustrate a similar process for defining a reference plane (and a plane orthogonal thereto) and recording position and/or orientation information at first and second reference positions prior to surgical manipulation of a patient's anatomy.FIG. 18Dillustrates that, in some embodiments, initial measured or calculated position and/or orientation data can be immediately displayed to a user. Such information can include, for example, the angle200between the first and second reference points as projected into the reference plane, as well as the angle202between the first and second reference points as projected into the plane orthogonal to the reference plane.

InFIG. 18E, a step of simultaneously pressing the second button178cand the third button178cto save the captured information is illustrated. Alternatively, a user could re-take the measurements ofFIGS. 18A-Cif, for example, the instrument was improperly positioned, etc. As shown inFIG. 18F, at subsequent times the saves data can be recalled to the display176by simultaneously pressing the second and third buttons178b,178cagain.

FIGS. 18G-18Jillustrate method steps similar to those described above and illustrated inFIGS. 17D-Gthat can be performed following surgical manipulation of a patient's anatomy174. These can include redefining the reference plane (FIG. 18G), capturing data from the first and second positions (FIGS. 18H and 18I), and displaying measured and calculated position and/or orientation data to a user via the display176(FIG. 18J).

FIGS. 19A-19Dillustrate still another embodiment of a method of operation of an instrument for intraoperatively measuring anatomical orientation having a three-button interface. In this embodiment, the electronic module170and instrument172can be utilized without pre- and post-manipulation measurement comparisons to measure position and/or orientation changes between two reference points at any time. The method illustrated inFIGS. 19A-19Dmirrors that described above and illustrated inFIGS. 18A-18D. For example, the method can include defining a reference plane into which angles can be projected (FIG. 19A), capturing position and/or orientation data at a first position (FIG. 19B) and a second position (FIG. 19C) and displaying measured or calculated data to a user (FIG. 19D). The displayed data can include, for example, a first angle200between the first and second reference positions measured in the reference plane and a second angle202between the first and second reference positions measured in a plane orthogonal to the reference plane.

FIG. 20A-20Dillustrate one embodiment of a method of operating an osteotome210with a disposable sensor pod or module212that can be selectively coupled thereto. In particular, a housing214of the module212can include one or more engagement features216configured to interface with complementary features on the osteotome210(or other surgical instrument) to removably attach the housing thereto. Examples of engagement features216can include a protrusion, recess, latch, or other feature.

The module212can include a single button input218that can be used to operate the module in a manner similar to the method described above and illustrated inFIGS. 9A-12. In the illustrated embodiment, the module212includes a different type of display220that conveys first angle information222related to a reference plane and second angle information224related to a plane orthogonal to the reference plane using two illuminated indicators oriented orthogonally to one another.

FIGS. 20B-20Dillustrate one example of a method of operating the module212. Similar to the methods described above, the illustrated method can include positioning the osteotome in a first orientation, zeroing a display of orientation relative to gravity, moving the osteotome to a second orientation, and displaying a change in orientation relative to the first orientation. More particularly, as shown inFIG. 20Bthe osteotome210can be placed in a first reference position and the module212can indicate an initial angular orientation relative to gravity or the earth. A user can press the input button218, as shown inFIG. 20C, to zero the module212when in the first reference position. The user can then move the osteotome210to a second reference position, as shown inFIG. 20D, and read the angular indications from the display220that are now shown relative to the first reference position.

FIGS. 21A-21Billustrate one embodiment of a tool230that can be used in conjunction with the module212to determine pedicle screw trajectory. As shown inFIG. 21A, the tool230can be aligned with an axis of a first pedicle screw Ap1being inserted into a patient's vertebra232and can record its position and/or orientation, e.g., by depressing the button218. Angles measured relative to a reference plane and a plane orthogonal thereto can be displayed on the display220using the illuminated indicators222,224. The tool can then be utilized to determine a mirroring pedicle axis Ap2orientation on an opposite side of a patient's vertebra232, as shown inFIG. 21B. For example, a user can adjust a position of the tool230until the display220has a matching angular displacement readout, or the module212can be configured to flash the indicators222,224or otherwise communicate feedback to a user when the position and/or orientation mirrors the orientation recorded as shown inFIG. 21B. The tool230and module212can thereby provide for symmetric insertion of pedicle screws on opposite sides of the spine. This can create an additional benefit of permitting similarly formed spinal fixation elements, such as spinal fixation rods, to be utilized on both sides of the patient's spine. Eliminating time spent customizing rod shape on each side of the spine can greatly increase the efficiency of a surgeon or other user by reducing complexity and time for a spinal correction procedure.

FIGS. 22A-22Billustrate another embodiment in which sensors242,244are coupled to a tool240used to bend a spinal fixation rod246. The sensors242,244can detect an angle of bend imparted to the rod246by the tool240, and this angle can be displayed to a user on a display248coupled to the tool. In other embodiments described in more detail below, the sensors242,244can be coupled to the rod246directly to detect a degree of bend imparted thereto in one or more planes.

FIG. 23is a schematic illustration of an exemplary system300for measuring anatomical position and/or orientation. As shown, the system can include one or more sensors302of the type described herein, a computer system304with an electronic display (e.g., a tablet computer, a laptop computer, a mobile device, or the like), and a software application executed by the computer system. The software application can receive user inputs via, e.g., a keyboard, touch-screen display, etc. and can display various information to a user using a graphical user interface306, such as data received from the sensors or information calculated using such data. The system can be configured to measure and/or calculate various anatomical parameters, including the various spinopelvic parameters shown inFIG. 24, such as thoracic kyphosis (TK), lumbar lordotic angle (LLA), sagittal vertical axis (SVA), sacral slope (SS), pelvic tilt (PT), and pelvic incidence (PI).

An exemplary method of using the system300is shown schematically inFIGS. 25A-25H.FIG. 25Aillustrates initial setup of the system300for embodiments that make use of a reusable tablet310and a disposable display312. One distinction between the two versions can be that a reusable tablet310may not be sterile and, as a result, can communicate wirelessly with one or more sensors314that are sterilized and provided in sterile packaging. In the disposable display embodiment312, all components can be sterilized and wired connections between the display and sensors can be employed because all components can be brought into the sterile field.

FIG. 25Billustrates removal of the various system components from a sterile packaging319. As shown, the system can include a reference plane sensor320and one or more angle sensors322. The system can also include a power and communication pod324which can be coupled to a reusable tablet or other computer system, or to a disposable computer system. The sensors322can be wired or wireless (e.g., Bluetooth, Wi-Fi, etc.). In the case of wired sensors, the wire size can be less than 5 mm. The sensors322can be approximately dime-sized, e.g., less than about 18 mm in diameter or width. Low profile sensors322can be used, for example sensors having a width less than 7 mm and a length less than 10 mm. In some embodiments, the sensors322do not include a housing, display, buttons, etc. It will be appreciated that sensors322and/or wires having any size can be used. The sensors322can be inertial measurement sensors, e.g., a 9-axis inertial measurement sensor with a gyroscope, magnetometer, and accelerometer. Other sensor types can also be used, including optical, infrared, ultrasound, RF, video tracker, video surface, fiber optic, surface RPT, laser scan, electromagnetic, combinations of sensors, and any sensors described herein.

FIG. 25Cillustrates various mounts for attaching the angle sensors322to the patient. It will be appreciated that any of the mounts disclosed above can be used instead or in addition. The illustrated mounts include a clamp326for attaching to the spinous process or other anatomical structure, a Steinman pin or pedicle screw328, and an alligator clip330. The mounts can be less than 1 inch in height in some embodiments.

FIG. 25Dillustrates placement of the angle sensors322with respect to the patient. The sensors322can be placed at any of a variety of locations on the patient. In an exemplary embodiment for measuring global spinal angles, such as lumbar lordosis and/or thoracic kyphosis, the sensors can be mounted in different regions of the patient's spine. For example, a sensor can be mounted at each of S1, L1, and T4as shown by sensors322a,322b, and322c. While not shown, sensors can also be mounted to the cervical spine to measure position or orientation of that region. The same or a similar arrangement of sensors can be used to measure coronal and derotation spinal angles.

FIG. 25Eillustrates establishment of a reference plane332(e.g., the sagittal plane of the patient) using the reference plane sensor320. The reference plane sensor320can be the same as the angle sensors322, and can include any of the same features as the angle sensors. The reference plane sensor320can include reference markings or indicia to guide a user in aligning the sensor with the patient. For example, a housing of the sensor can be human-shaped, or can include head and feet markings to indicate proper orientation. The housing can include a flat surface to allow the housing to be laid against the patient or the operating table. The housing can include a longitudinal line indicator configured to be aligned by the user with the patient's sagittal plane. In use, the user can position the reference plane sensor320in alignment with the patient's sagittal plane and push a button on the sensor to establish the current sensor position as the reference plane. The sagittal plane of the patient can move during the course of a surgery, especially in scoliosis and other cases where significant correction is performed. Accordingly, at any time the user desires, the reference plane332can be re-established by picking up the sensor320, aligning it, and pushing the button to capture the current position as the reference plane.

FIG. 25Fillustrates capture of patient and sensor images. The images can be captured from a lateral perspective as shown. The image can be captured using fluoroscopy, MRI, CT, or other imaging techniques. The captured image can be communicated to the software application executing on the computer system304(e.g., tablet310). For example, an image capture device334used to capture the image can be integrated with the computer system304or can be coupled thereto (e.g., via a wireless or USB connection). The image can also be communicated using a camera of the computer system304to capture an image of a display screen on which the patient image is shown. For example, the integrated camera on the tablet computer310can be used to take a picture of the display screen of a fluoroscope to load the patient image into the tablet computer. The angle sensors322can be radiopaque, magnetic, metallic, or can have other properties that allow them to be visualized in the patient image. It will be appreciated that, in the case of fluoroscopy, only a small number of fluoro-shots are needed to capture an image of the sensors and of the patient anatomy (e.g., less than 3 shots, less than 2 shots, and/or a single shot in certain embodiments).

In some cases, a user might position the angle sensors322such that their sensor axis is slightly offset from the endplate plane of the patient's vertebrae. The system can be configured to apply a correction such that angles or other measurements made by the angle sensors322can be calculated relative to the endplates.FIG. 25Gillustrates an endplate definition step. As shown, an electronic display336of the computer system304(e.g., tablet310) can display the captured patient image338, showing the angle sensors322. The computer system304can execute an image processing routine to identify the angle sensors322within the image338and to display a visual indicator340of the sensor axis to the user (a dotted line in the illustrated example). The user can then interact with the computer system304, e.g., using a touch screen, mouse, or other input device, to draw a line parallel to the vertebral endplate342(a solid line with circular endpoints in the illustrated example). The computer system304can then calculate an angular offset between the sensor axis340and the user-input endplate plane342to determine a correction factor344(15 degrees in the illustrated example). This process can be performed for each of the angle sensors322. Once complete, these compensatory angles can be used along with the angles measured by the angle sensors322to calculate actual absolute endplate angles, including regional angles such as lumbar lordosis, thoracic kyphosis, etc. The system can also track changes in such angles. The same or a similar approach can be used to determine coronal and/or axial angles, e.g., to obtain six degree-of-freedom information of the three-dimensional spine.

FIG. 25Hillustrates the system software displaying on an electronic display336one or more measurements captured using the system. For example, the system can display the absolute lumbar lordosis angle346and the absolute thoracic kyphosis angle348as shown. The system can also display other spinopelvic parameters, such as pelvic incidence, pelvic tilt, sagittal vertical axis, PI-LL, and so forth. The system can also display changes in any of these parameters. The system can display these measurements in real-time as the surgery is performed and as any corrections are applied to the patient's spine.

In some embodiments, measurement of certain spinopelvic parameters can allow for calculation of others. For example, the following formulas can be used to calculate pelvic tilt and sagittal vertical axis:
PT=1.14+0.71×(PI)−0.52×(maximal lumbar lordosis)−0.19×(maximal thoracic kyphosis)
SVA=−52.87+5.90×(PI)−5.13×(maximal lumbar lordosis)−4.45×(PT)−2.09×(maximal thoracic kyphosis)+0.513×(patient age)

The system300can be used in any type of surgery, including open surgery and percutaneous or minimally-invasive surgery (MIS). As shown inFIG. 26A, the angle sensors322can be attached to the patient using percutaneous mounts350in some embodiments. Each mount350can include an elongate needle portion352that can be docked into vertebral bone of the patient to support the mount and attach the mount to the patient anatomy. A proximal end of the mount can include a recess354that can receive a sensor322and a set screw356. The mount350can be selectively mated to a driver358to facilitate application of a rotational torque to the set screw356and/or to the mount350itself. The mount350can thus serve as a modular instrument for degenerative and MIS procedures, allowing for global alignment and measurement via a percutaneous approach.

While use of the system is described above in the context of measuring various absolute spinal angles, it will be appreciated that the system can be used in any of a variety of other applications. For example, as shown inFIG. 26B, the system300can be used to measure a bend angle of a spinal rod360or other implant by coupling the angle sensors322thereto using clamps or other attachment mechanisms362. As shown inFIG. 26C, the system300can also be used to measure a correction or change in position associated with a derotation maneuver, for example by coupling the angle sensors322to bone anchors, extension tabs, quick sticks, or other implants or instrumentation364attached to the vertebrae366being corrected. As shown inFIG. 26D, the system300can measure an osteotomy angle by attaching the angle sensors322to bone anchors, osteotomy frames, osteotomy clamps, or other implants or instrumentation368attached on either side of an osteotomy370.

FIGS. 27A-27Jillustrate exemplary software functionality of the system, e.g., as implemented using a software application executing on a computer system304comprising a processor and a memory. As shown inFIG. 27A, the system can include a patient information module380for receiving user information relating to the patient and for displaying information related to the patient. The patient information module can facilitate entry and/or display of various attributes of the patient, including name, age, sex, pre-operative anatomical measurements, notes, patient images, and so forth. The patient input module can display a graphical representation382or an actual image of the patient's spine. Entered information can be saved to a storage unit or database of the computer system.

As shown inFIG. 27B, the system can support use with multiple patients, and can include a patient selection screen384for selecting the current patient.

As shown inFIG. 27C, the system can include a planning module386. The planning module386can permit entry of pre-operative planned corrections388and can calculate and display a predictive post-operative estimate390. For example, a correction can be entered by specifying one or more locations (e.g., T10and L3as shown at ref. no.388) and a correction angle to be performed at each level, for example via osteotomy. Based on the entered correction information, the system can calculate and display a predictive post-operative estimate390. In the illustrated embodiment, a 10-degree correction at T10and a 12 degree correction at L3are estimated to result in a −30-degree post-operative kyphosis angle as compared to a −40-degree pre-operative kyphosis angle, a 42-degree post-operative lordosis angle as compared to a 30-degree pre-operative lordosis angle, a 28-degree post-operative pelvic tilt as compared to a 36-degree pre-operative pelvic tilt, and a 57 mm post-operative sagittal vertical axis (SVA) as compared to a 103 mm pre-op SVA. The user can continue entering or editing proposed corrections until the desired post-operative geometry is displayed, thereby establishing a surgical plan.

As shown inFIG. 27D, the system can include a main menu screen392from which a user can begin a new procedure, recall a saved procedure, perform a quick measurement, change or view administrative settings, or exit the software application.

As shown inFIG. 27E, the system can include a sensor connection module394. The sensor connection module394can display the connection status of the various sensors320,322of the system to the software application and other information such as the MAC address or other identifier associated with the sensor. This information can be utilized by a surgeon or other user to ensure proper set-up of the system prior to use.

As shown inFIG. 27F, the system can include a sensor positioning module396. The sensor positioning module can help guide a user in proper sensor placement. For example, the sensor positioning module396can control LEDs or other indicators on the sensors322to give the user an indication as to the use or positioning of any particular sensor. In the illustrated example, the sensor positioning module396can cause angle sensors for measuring a local angle to illuminate a blue (or other color) LED, and can display a color-coded graphical depiction398of the desired placement of the sensors relative to the patient. Similarly, the sensor positioning module396can cause angle sensors for measuring a global angle to illuminate a green (or other color) LED, and can display a color-coded graphical depiction400of the desired placement of the sensors relative to the patient.

As shown inFIG. 27G, the system can include a reference plane calibration module402. The reference plane calibration module can instruct the user to position the reference plane sensor320as shown to establish the sagittal plane of the patient (e.g., by correlating the sensor coordinate system to the patient's sagittal plane). In some embodiments, the calibration module402can perform a one-step calibration, in which the user simply aligns the reference plane sensor with the patient's sagittal plane and pushes a button on the sensor to establish the reference plane.

As shown inFIG. 27H, the system can include an intuitive measurement screen404for various corrections, such as multi-level osteotomies as shown. The measurement screen404can include any of the various measured or calculated values described above, including comparisons of planned to actual values for various spinopelvic parameters.

As shown inFIG. 27I, the system can include an option to use one or more of the angle sensors322for tracking an instrument during the surgery. For example, one of the local angle sensors can be attached to an osteotome to allow a position and/or orientation of the osteotome to be measured before and during bone cutting. In such an embodiment, an instrument tracking module406can instruct a user regarding which sensor322should be detached from the patient's anatomy and coupled to the instrument to be tracked. The module406can further provide for designating the type of instrument being tracked such that any necessary calibration can be performed and/or data regarding the instrument loaded from a data store.

As shown inFIG. 27J, the system can display angles measured in various planes, including, for example, sagittal plane408and axial plane410angle measurements. Accordingly, and as noted above, the system can be capable of measuring and calculating position and/or orientation data in both a reference plane and plane orthogonal to the reference plane.

The above system can be used to intraoperatively validate global spinal alignment. The system can allow continuous intraoperative monitoring, assessment, and validation of global alignment from the time a patient is placed on the operating table to the completion of the spinal deformity correction. The system can facilitate accurate and continuous intraoperative alignment validation during spinal reconstruction, which can be used to assist in measurement of the orientation of the anatomical regions of the spine prior to closing the wound when actions can still be taken to correct a less than optimal correction. The system can allow continuous validation of global spinal alignment, active real absolute value measurement of different regions of the spinal curve including thoracic kyphosis, lumbar lordosis, scoliosis and axial derotation, maintain association between standing and prone global alignment, allow spinopelvic parameter estimation, reduce wound exposure time, reduce number of steps, reduce setup errors, reduce frustration, improve speed, and enable ease of use. The system can allow segmental and global validation, measure sagittal, axial, and coronal angles, minimize setup time, enable simple calibration, provide an intuitive user interface workflow, provide accurate, repeatable and reproducible results, be adaptive to multi-level correction, use sensors having a size comparable to other instruments, and use modular sensor clips.

The system can allow surgeons to estimate spinal alignment correction achieved due to patient positioning, allow surgeons to estimate sagittal balance in concurrence with vertebral derotation, allow degenerative and MIS surgeons to maintain spinal alignment during surgery, assist surgeons in spinal rod bending, derotation maneuvers, and osteotomy closures, intraoperatively measure spinal correction achieved at each regional curve (e.g., lordosis, kyphosis, and scoliosis), maintain association between standing and prone patient position, provide actual regional angular value measurements and relative monitoring of the change in values during the correction, and/or allow monitoring of sagittal balance during degenerative and MIS cases.

The system can allow for optimization of interbody cage placement in some embodiments. For example, the system can be used to measure how much an interbody cage expanded disc space or corrected an angle in real time. In the case of expandable or adjustable cages, the system can be used to inform expansion or contraction of the cage based on real-time measurement of the achieved correction. This can increase the efficiency of operations to implant such cages.

Entire setup of the system can be completed before an actual osteotomy and correction is performed. As soon as setup is complete, a surgeon or other user can measure and associate changes in sagittal balance due to patient positioning. The surgeon can re-plan execution due to any correction achieved from patient positioning. The system can track changes in actual absolute regional angles due to operative execution. The system can allow continuous validation without requiring additional fluoro-shots, which is not possible with existing systems that require new fluoro-images be captured each time sagittal balance is to be validated.

Restoration of spinal global alignment can be important in complex spinal deformity surgery. Spinal osteotomies are established surgical techniques to correct spinopelvic malalignment. Reports have demonstrated that improved sagittal spinal alignment following spinal osteotomies correlate with improved health related quality of life (HRQOL) scores. Spine osteotomies can be broadly divided into four main types: Smith-Petersen, Ponte, Pedicle Subtraction Osteotomy (PSO), and Vertebral Column Resection (VCR). The type of osteotomy used depends on both the location of the spinal deformity and on the amount of correction that is required. A spinal fusion with instrumentation may also be performed along with spine osteotomy to stabilize the spine and prevent further curvature. It is commonly reported that many times outcome of these surgeries can result in negative impact of sagittal balance resulting in disability, pain, deficient forward gaze and poor health related quality of life (HRQOL). An intraoperative monitoring of the sagittal balance can help achieve optimum outcomes when treating spinal disorders. Even when addressing problems in the coronal and axial plane, an awareness of sagittal balance can avoid future complications. Global spinal malalignment is often difficult to assess and measure during the surgery when the patient is in the prone position. However, surgery is the crucial period because it is during surgery that alignment can be corrected. Currently there is no quick way to measure sagittal balance and regional curves intraoperatively during deformity and degenerative surgeries. Current techniques include in-vivo use of many cobbled together methods including a combination of “eyeballing,” experience, estimation, multiple fluoro-images, or the use of templates, wedges, or rasps to estimate spinal angular correction to facilitate intra-operative validation of the global alignment to spinal reconstruction. In some cases, the technique is to take fluoro-images, send them to a PACs system, and use the images to measure correction using a manual protractor. This technique requires the surgeon to leave the sterile field, which is not desirable and results in increased surgery time. In addition, placing that patient prone on the operating table can change their global alignment and regional curves from what has been assessed in standing pre-operative film. This change in correction due to the patient positioning can warrant a change in the original plan for the osteotomy execution.

The instruments disclosed herein can be designed to be disposed of after a single use, or they can be designed to be used multiple times. In either case, however, the instrument can be reconditioned for reuse after at least one use. Reconditioning can include any combination of the steps of disassembly of the instrument, followed by cleaning or replacement of particular pieces, and subsequent reassembly. In particular, the instrument can be disassembled, and any number of the particular pieces or parts of the instrument can be selectively replaced or removed in any combination. Upon cleaning and/or replacement of particular parts, the instrument can be reassembled for subsequent use either at a reconditioning facility, or by a surgical team immediately prior to a surgical procedure. Those skilled in the art will appreciate that reconditioning of an instrument can utilize a variety of techniques for disassembly, cleaning/replacement, and reassembly. Use of such techniques, and the resulting reconditioned instrument, are all within the scope of the present disclosure.

The instruments described herein can be processed before use in a surgical procedure. First, a new or used instrument can be obtained and, if necessary, cleaned. The instrument can then be sterilized. In one sterilization technique, the instrument can be placed in a closed and sealed container, such as a plastic or TYVEK bag. The container and its contents can then be placed in a field of radiation that can penetrate the container, such as gamma radiation, x-rays, or high-energy electrons. The radiation can kill bacteria on the instrument and in the container. The sterilized instrument can then be stored in the sterile container. The sealed container can keep the instrument sterile until it is opened in the medical facility. Other forms of sterilization known in the art are also possible. This can include beta or other forms of radiation, ethylene oxide, steam, or a liquid bath (e.g., cold soak). Certain forms of sterilization may be better suited to use with different portions of the instrument due to the materials utilized, the presence of electrical components, etc.

One skilled in the art will appreciate further features and advantages of the disclosure based on the above-described embodiments. Accordingly, the disclosure is not to be limited by what has been particularly shown and described, except as indicated by the appended claims. All publications and references cited herein are expressly incorporated herein by reference in their entirety.