Cross-Reference to Related Applications

This application claims the benefit of U.S. Provisional Patent Application No.

62/137,698, filed on March 24, 2015, entitled "SYSTEMS AND METHODS FOR MULTIDIMENSIONAL VISUALIZATION OF ANATOMY AND SURGICAL INSTRUMENTS," the disclosure of which is expressly incorporated herein by reference in its entirety.

Technical Field

[0001] The present disclosure relates generally to orthopedic surgery and, more particularly, to a system and method for intra-operative multi-dimensional visualization of the patient's anatomy and surgical instruments used in the surgery.

Background

[0002] Many orthopedic surgeries, such as those involving the spine, are complex procedures that require a high degree of precision. For example, the spine is in close proximity to delicate anatomical structures such as the spinal cord and nerve roots. Compounding the problem is limited surgical exposure and visibility, particularly in the case of minimally invasive procedures. Consequently the risk of misplaced implants or other complications is high.

[0003] To combat the above problem, computer-assisted navigation and robotic systems are routinely used. Although these systems have the promise to improve precision of the surgery, they are typically expensive, bulky and cumbersome to use and add both cost and time to the procedure. Additionally, image-guided systems require repeated intraoperative imaging (e.g. fluoroscopy, CT scan, etc) which subjects the patient and surgical team to high doses of radiation.

[0004] Given the above, a computer-assisted solution that is accurate, easy-to-use, and low cost is extremely desirable, particularly if it minimizes the amount of radiation exposure for the patient and surgical team. Summary

[0005] According to one aspect, the present disclosure is directed to a method for estimating a pose (e.g., position and/or orientation) of an anatomy and creating a multi dimensional visualization (e.g., a virtual anatomic model) of the anatomy for intra operative tracking and guidance. The method includes receiving multi dimensional images of the anatomy that are then used to create a virtual multi dimensional model (also referred to herein as a virtual anatomic model) of the anatomy. The method further includes registration of the patient's anatomy involving receiving from inertial and magnetic sensors information indicative of a first pose of the anatomy relative to the virtual model. The method further includes real-time tracking of the pose of the anatomy and multi dimensional visualization of the virtual model by receiving information from inertial and magnetic sensors attached to the patient's anatomy.

[0006] In accordance with another aspect, the present disclosure is directed to a method for estimating a pose of a surgical instrument relative to a patient's anatomy. The method includes receiving multi dimensional images or CAD model of the surgical instrument to create a virtual model. The method further includes real-time tracking of the surgical instrument and multi dimensional visualization of the surgical instrument by receiving information from inertial and magnetic sensors attached to the surgical instrument.

[0007] In accordance with another aspect, the present disclosure is directed to a system for estimating a pose of an anatomy or surgical instrument relative to the anatomy. The system includes inertial sensors and magnetic sensors coupled to a patient's anatomy. The system also includes a magnetic field generator in proximity to the surgical field, such as underneath the patient. The system also includes a processor, communicatively coupled to the inertial sensors and magnetic sensors. The processor may be configured to create a virtual multi dimensional model of the anatomy from 2D or 3D images. The processor may also be configured to register one or more axes, planes, landmarks, or surfaces associated with a patient's anatomy. The processor may be further configured to estimate the pose of the patient's anatomy during surgery and animate/visualize the virtual model in real-time without the need for additional imaging. The processor may be further configured to estimate geometrical relationship between a surgical instrument and the patient's anatomy. Brief Description of the Drawings

[0008] Fig. 1 provides a diagrammatic view of an example sensor system used to measure pose of patient's anatomy consistent with certain disclosed embodiments.

[0009] Fig. 2 provides a diagrammatic view of an example sensor system used to measure pose of a surgical instrument consistent with certain disclosed embodiments.

[0010] Fig. 3 provides a schematic view of example components associated with a sensor system used to measure pose of an anatomy and/or surgical instruments, such as that illustrated in Figs. 1 and 2.

[0011] Fig 4 provides a flow of an example method associated with a sensor system used to measure pose of an anatomy and/or surgical instrument.

Detailed Description

[0012] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. Methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present disclosure. As used in the specification, and in the appended claims, the singular forms "a," "an," "the" include plural referents unless the context clearly dictates otherwise. The term "comprising" and variations thereof as used herein is used synonymously with the term

"including" and variations thereof and are open, non-limiting terms. The terms "optional" or "optionally" used herein mean that the subsequently described feature, event or circumstance may or may not occur, and that the description includes instances where said feature, event or circumstance occurs and instances where it does not. Ranges may be expressed herein as from "about" one particular value, and/or to "about" another particular value. When such a range is expressed, an aspect includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent "about," it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0013] Systems and methods consistent with the embodiments disclosed herein are directed to a sensor-based system to measure the pose of a patient's anatomy as well as the pose of surgical instruments relative to the patient's anatomy. The systems and methods do not rely on expensive tracking or robotic equipment. As used herein, pose is defined as position (Χ,Υ,Ζ) and/or orientation (pitch, yaw, roll) with respect to a coordinate frame. Systems and methods consistent with the disclosed embodiments also limit the number of hardware components and steps needed to calibrate the system for use, potentially reducing the time and cost burden associated with the procedure. Certain exemplary embodiments minimize the need for "image-based guidance," meaning that they do not rely on intra-operative imaging (X-ray, computed tomography (CT) or magnetic resonance imaging (MRI)), which can add additional time and cost to the procedure and subj ect the patient to unnecessary exposure to potentially harmful radiation.

[0014] Fig. 1 provides a view depicting an example spine surgical system to measure the pose of a patient's anatomy. As illustrated in Fig. 1, the spine surgical system 300 provides a solution for creating a virtual model of the anatomy 310, registering one or more anatomic axes, planes, landmarks, surfaces, or features, measuring the pose of the anatomy and displaying this information in real-time. Fig 2 provides a view depicting an example spine surgical system 300 to measure the pose of a surgical instrument 330 relative to a patient's anatomy 310. As illustrated in Fig. 2, in addition to the features of the system depicted in Fig 1 , the spine surgical system provides a solution for creating a virtual model of the surgical instrument, measuring the orientation and position of the surgical instrument relative to the anatomy and displaying this information in real-time. It should be understood that the spine is provided as only one example of the patient's anatomy and that the systems and methods described herein are applicable to anatomy other than the spine. For example, those skilled in the art will recognize that embodiments consistent with the presently disclosed systems and methods may be employed in any environment involving arthroplastic procedures, such as the hip, knee, and shoulder.

[0015] As illustrated in Fig. 1 and 2, the system 300 comprises sensing modules 340 and magnetic field generator 320 coupled to a processing and display unit 350. Each sensing module 340 can be a set of magnetic and inertial sensors as described herein. At least 3 modules are utilized and placed on the spine 310 at specific known locations. For example, one module may be placed at the base of the spine 310, another may be placed at the bottom of the thoracic spine and another may be placed at the top of the thoracic spine. Other locations may be selected by the surgeon to achieve specific goals of the surgery. The modules are placed on the spine 310 using orthopedic screws or pins commonly used in such procedures. Alternatively, the modules may be attached using custom clamps or quick connect/disconnect mechanisms or any means that ensures rigid fixation the spine 310. They can be placed on any suitable anatomical feature of the spine that allows for rigid fixation such as the spinous processes. Also as illustrated in Fig 2, modules 340 may be rigidly fixed on surgical instruments 330 at specified locations such that geometric relationship between module 340 and the surgical instrument is known. Note that although there is no technical limitation on the number of modules that can be used, a practical limit is expected to be around 10 modules. However the quantity of modules used does not interfere with or limit the disclosure in any way.

[0016] The modules 340 may also include one or more inertial sensors. According to one embodiment, inertial sensors may include or embody one or more of gyroscopes and accelerometers. The modules 340 may also include magnetic sensors such as magnetometers. Inertial sensors measure earth's gravity as well as linear and rotational motion that can be processed to calculate orientation relative to a reference coordinate frame. Magnetic sensors measure the strength and/or direction of a magnetic field, for example the strength and direction of the magnetic field emanation from magnetic field generator 320. Using "sensor fusion" algorithms, some of which are well known in the art, the inertial sensors and magnetic sensors may combine to measure full 6 degree-of-freedom (DOF) motion and pose relative to a reference coordinate frame. 6 DOF motion refers to rotational and linear motion about all 3 axes. Inertial and magnetic sensors consistent with the disclosed embodiments are described in greater detail below with respect to the schematic diagram of Fig. 3.

[0017] The modules 340 associated with the presently disclosed system may each be configured to communicate wirelessly with each other and to a processing and display unit 350 that can be a laptop computer, PDA, or any portable, wearable or desktop computing device. The wireless communication can be achieved via any standard radio frequency communication protocol such Bluetooth, Wi Fi, ZigBee, etc., or a custom protocol. In some embodiments, wireless communication is achieved via wireless communication transceiver 360, which may be operatively connected to processing and display unit 350.

[0018] The processing and display unit 350 runs software that calculates the pose of the anatomy 310 and/or surgical instrument 330 based on the sensor readings and displays the information on a screen in a variety of ways based on surgeon preferences. The surgeon or surgical assistants can interact with the processing unit either via a keyboard, wired or wireless buttons, touch screens, voice activated commands, or any other technologies that currently exist or may be developed in the future.

[0019] In addition to their role as described above, modules 340 also allow a means for the system to register anatomic axes, planes, landmarks, surfaces, and/or features as described herein. Once registered, modules 340 can be used to measure the pose of the anatomy 310 as well as the pose of the surgical instruments 330 relative to the anatomy. [0020] Fig. 3 provides a schematic diagram illustrating certain exemplary subsystems associated with system 300 and its constituent components. Specifically, Fig. 3 is a schematic block diagram depicting exemplary subcomponents of processing and display unit 350, and sensing modules 340.

[0021] For example, in accordance with the exemplary embodiment illustrated in Fig. 3, system 300 may embody a system for intra-operatively - and in real-time or near real-time - measuring pose of an anatomy or surgical instrument. As illustrated in Fig. 3, system 300 may include a processing device (such as processing and display unit 350 (or other computer device for processing data received by system 300)), and one or more wireless communication transceivers 360 for communicating with the sensors attached to the patient's anatomy (not shown). The components of system 300 described above are examples only, and are not intended to be limiting. Indeed, it is contemplated that additional and/or different components may be included as part of system 300 without departing from the scope of the present disclosure. For example, although wireless communication transceiver 360 is illustrated as being a standalone device, it may be integrated within one or more other components, such as processing and display unit 350. Thus, the configuration and arrangement of components of system 300 illustrated in Fig. 3 are intended to be examples only.

[0022] Processing and display unit 350 may include or embody any suitable microprocessor- based device configured to process and/or analyze information indicative of the pose of an anatomy or surgical instrument. According to one embodiment, processing and display unit 350 may be a general purpose computer programmed with software for receiving, processing, and displaying information indicative of the pose of the spine. According to other embodiments, processing and display unit 350 may be a special-purpose computer, specifically designed to communicate with, and process information for, other components associated with system 300. Individual components of, and processes/methods performed by, processing and display unit 350 will be discussed in more detail below.

[0023] Processing and display unit 350 may be communicatively coupled to the sensing module(s) (e.g., sensing modules 340 and/or any additional orientation sensors (not shown) used in system 300) and may be configured to receive, process, and/or analyze data measured by the sensing modules. According to one embodiment, processing and display unit 350 may be wirelessly coupled to modules 340 via wireless communication trans ceiver(s) 360 operating any suitable protocol for supporting wireless (e.g., wireless USB, ZigBee, Bluetooth, Wi-Fi, etc.) In accordance with another embodiment, processing system 350 may be wirelessly coupled to modules 340, which, in turn, may be configured to collect data from the other constituent sensors and deliver it to processing and display unit 350. In accordance with yet another embodiment, certain components of processing and display unit 350 (e.g. I/O devices 356) may be suitably miniaturized for integration with modules 340.

[0024] Wireless communication transceiver(s) 360 may include any device suitable for supporting wireless communication between one or more components of system 300. As explained above, wireless communication transceiver(s) 360 may be configured for operation according to any number of suitable protocols for supporting wireless, such as, for example, wireless USB, ZigBee, Bluetooth, Wi-Fi, or any other suitable wireless communication protocol or standard. According to one embodiment, wireless communication transceiver 360 may embody a standalone communication module, separate from processing and display unit 350. As such, wireless communication transceiver 360 may be electrically coupled to processing and display unit 350 via USB or other data communication link and configured to deliver data received therein to processing and display unit 350for further processing/analysis. According to other embodiments, wireless communication transceiver 360 may embody an integrated wireless transceiver chipset, such as the Bluetooth, Wi-Fi, NFC, or 802.1 lx wireless chipset included as part of processing and display unit 350.

[0025] As explained, processing and display unit 350 may be any processor-based computing system that is configured to receive pose information associated with an anatomy or surgical instrument (e.g., via the sensing modules), store anatomic registration information, analyze the received information to extract data indicative of the pose of the surgical instrumentation with respect to the patient's anatomy, and output the extracted data in real-time or near real-time. Non-limiting examples of processing and display unit 350 include a desktop or notebook computer, a tablet device, a smartphone, wearable or handheld computers, or any other suitable processor-based computing system.

[0026] For example, as illustrated in Fig. 3, processing system 350 may include one or more hardware and/or software components configured to execute software programs, such as algorithms for tracking the pose of the anatomy and/or surgical instruments. This disclosure contemplates using any algorithm known in the art for tracking the pose of the anatomy and/or the surgical instrument. According to one embodiment, processing and display unit 350 may include one or more hardware components such as, for example, a central processing unit (CPU) or microprocessor 351, a random access memory (RAM) module 352, a read-only memory (ROM) module 353, a memory or data storage module 354, a database 355, one or more input/output (I/O) devices 356, and an interface 357. Alternatively and/or additionally, processing and display unit 350 may include one or more software media components such as, for example, a computer-readable medium including computer-executable instructions for performing methods consistent with certain disclosed embodiments. It is contemplated that one or more of the hardware components listed above may be implemented using software. For example, storage 354 may include a software partition associated with one or more other hardware components of processing and display unit 350. Processing and display unit 350 may include additional, fewer, and/or different components than those listed above. It is understood that the components listed above are examples only and not intended to be limiting.

[0027] CPU 351 may include one or more processors, each configured to execute instructions and process data to perform one or more functions associated with processing and display unit 350. As illustrated in Fig. 3, CPU 351 may be communicatively coupled to RAM 352, ROM 353, storage 354, database 355, I/O devices 356, and interface 357. CPU 351 may be configured to execute sequences of computer program instructions to perform various processes, which will be described in detail below. The computer program instructions may be loaded into RAM 352 for execution by CPU 351.

[0028] RAM 352 and ROM 353 may each include one or more devices for storing information associated with an operation of processing and display unit 350 and/or CPU 351. For example, ROM 353 may include a memory device configured to access and store information associated with processing and display unit 350, including information for identifying, initializing, and monitoring the operation of one or more components and subsystems of processing and display unit 350. RAM 352 may include a memory device for storing data associated with one or more operations of CPU 351. For example, ROM 353 may load instructions into RAM 352 for execution by CPU 351.

[0029] Storage 354 may include any type of mass storage device configured to store information that CPU 351 may need to perform processes consistent with the disclosed embodiments. For example, storage 354 may include one or more magnetic and/or optical disk devices, such as hard drives, CD-ROMs, DVD-ROMs, or any other type of mass media device. Alternatively or additionally, storage 354 may include flash memory mass media storage or other semiconductor-based storage medium.

[0030] Database 355 may include one or more software and/or hardware components that cooperate to store, organize, sort, filter, and/or arrange data used by processing and display unit 350 and/or CPU 351. For example, database 355 may include historical data such as, for example, stored placement and pose data associated with surgical procedures. CPU 351 may access the information stored in database 355 to provide a comparison between previous surgeries and the current (i.e., real-time) surgery. CPU 351 may also analyze current and previous pose parameters to identify trends in historical data. These trends may then be recorded and analyzed to allow the surgeon or other medical professional to compare the pose parameters with different prosthesis designs and patient demographics. It is contemplated that database 355 may store additional and/or different information than that listed above.

[0031] I/O devices 356 may include one or more components configured to communicate information with a user associated with system 300. For example, I/O devices may include a console with an integrated keyboard and mouse to allow a user to input parameters associated with processing and display unit 350. I/O devices 356 may also include a display including a graphical user interface (GUI) for outputting information on a display monitor 358a. For example, the virtual model of the anatomy 310 and/or the virtual model of the surgical instrument as described herein can be displayed on the display monitor 358a. In certain embodiments, the I/O devices may be suitably miniaturized and integrated with tool 310. I/O devices 356 may also include peripheral devices such as, for example, a printer 358b for printing information associated with processing and display unit 350, a user-accessible disk drive (e.g., a USB port, a floppy, CD-ROM, or DVD-ROM drive, etc.) to allow a user to input data stored on a portable media device, a microphone, a speaker system, or any other suitable type of interface device.

[0032] Interface 357 may include one or more components configured to transmit and receive data via a communication network, such as the Internet, a local area network, a workstation peer- to-peer network, a direct link network, a wireless network, or any other suitable communication platform. For example, interface 357 may include one or more modulators, demodulators, multiplexers, demultiplexers, network communication devices, wireless devices, antennas, modems, and any other type of device configured to enable data communication via a communication network. According to one embodiment, interface 357 may be coupled to or include wireless communication devices, such as a module or modules configured to transmit information wirelessly using Wi-Fi or Bluetooth wireless protocols. Alternatively or

additionally, interface 357 may be configured for coupling to one or more peripheral communication devices, such as wireless communication transceiver 360.

[0033] As explained, system consists of modules 340 comprising at least one magnetometer 345 that measure the direction and intensity of a magnetic field. These magnetometers are used to measure the direction and intensity of the magnetic field emanating from a magnetic field generator 320.

[0034] For example the magnetic field generator 320 could be a series of permanent magnets or electromagnets (i.e. a wound coil through which current is passed). In the case of an electromagnet, one or more coils may be utilized to create multiple magnetic fields that are at known positions and orientations to each other. The magnetic fields may be excited in a prescribed sequence and/or have different frequencies to distinguish themselves from each other. The magnetic field generator 320 may be communicatively coupled, either wirelessly or using a wireline protocol, to processing and display unit 350 and be controlled by CPU 351. The magnetic field generator 320 may be powered via a power supply, such as power supply 342, or be connected to mains power via a standard power outlet.

[0035] Module 340 may also include one or more subcomponents configured to detect and transmit information that either represents the pose or can be used to derive the pose of the module 340 (and, by extension, any object that is affixed relative to modules 340, such as a patient's anatomy). Module 340 may embody a device capable of determining a pose associated with any body to which module 340 is attached. According to one embodiment, orientation sensor(s) in module 340 may be an integrated measurement unit including a microprocessor 341, a power supply 342, and one or more of a gyroscope 343, an accelerometer 344, or a

magnetometer 345.

[0036] According to one embodiment, module 340 may contain a 3-axis gyroscope 343, a 3- axis accelerometer 344, and a 3-axes magnetometer 345. It is contemplated, however, that fewer of these devices with fewer axes can be used without departing from the scope of the present disclosure. For example, according to one embodiment, module 340 may include only a gyroscope and an accelerometer, the gyroscope for calculating the orientation based on the rate of rotation of the device, and the accelerometer for measuring earth's gravity and linear motion, the accelerometer providing corrections to the rate of rotation information (based on errors introduced into the gyroscope because of device movements that are not rotational or errors due to biases and drifts). In other words, the accelerometer may be used to correct the orientation information collected by the gyroscope. Similarly the magnetometer 345 can be utilized to measure a magnetic field and can be utilized to further correct gyroscope errors and also correct accelerometer errors. The use of redundant and complementary devices increases the resolution and accuracy of the pose information. The data streams from multiple sensors may be "fused" using appropriate sensor fusion and filtering techniques. An example of a technique that may be suitable for use with the systems and methods described herein is a Kalman Filter.

[0037] As illustrated in Fig. 3, microprocessor 341 of modules 340 may include different processing modules or cores, which may cooperate to perform various processing functions. For example, microprocessor 341 may include, among other things, an interface 341d, a controller 341c, a motion processor 341b, and signal conditioning circuitry 341a. Controller 341 c may also be configured to control and receive conditioned and processed data from one or more of gyroscope 343, accelerometer 344, and magnetometer 345 and transmit the received data to one or more remote receivers. The data may be pre-conditioned via signal conditioning circuitry 341a, which includes amplifiers and analog-to-digital converters or any such circuits. The signals may be further processed by a motion processor 341b. Motion processor 341b may be programmed with so-called "sensor fusion" algorithms to collect and process data from different sensors to generate error corrected pose information. The orientation component of the pose information may be a mathematically represented as an orientation or rotation quaternion, euler angles, direction cosine matrix, rotation matrix of any such mathematical construct for representing orientation known in the art. Accordingly, controller 341 c may be communicatively coupled (e.g., wirelessly via interface 341 d as shown in Fig. 3, or using a wireline protocol) to, for example, processing and display unit 350 and may be configured to transmit the pose data received from one or more of gyroscope 343, accelerometer 344, and magnetometer 345 to processing and display unit 350, for further analysis.

[0038] Interface 34 Id may include one or more components configured to transmit and receive data via a communication network, such as the Internet, a local area network, a workstation peer- to-peer network, a direct link network, a wireless network, or any other suitable communication platform. For example, interface 34 I d may include one or more modulators, demodulators, multiplexers, demultiplexers, network communication devices, wireless devices, antennas, modems, and any other type of device configured to enable data communication via a communication network. According to one embodiment, interface 341 d may be coupled to or include wireless communication devices, such as a module or modules configured to transmit information wirelessly using Wi-Fi or Bluetooth wireless protocols. As illustrated in Fig. 3, modules 340 may be powered by power supply 342, such as a battery, fuel cell, MEMs micro- generator, or any other suitable compact power supply.

[0039] Importantly, although microprocessor 341 of module 340 is illustrated as containing a number of discrete modules, it is contemplated that such a configuration should not be construed as limiting. Indeed, microprocessor 341 may include additional, fewer, and/or different modules than those described above with respect to Fig. 3, without departing from the scope of the present disclosure. Furthermore, in other instances of the present disclosure that describe a microprocessor are contemplated as being capable of performing many of the same functions as microprocessor 341 of modules 340 (e.g., signal conditioning, wireless communications, etc.) even though such processes are not explicitly described with respect to microprocessor 341. Those skilled in the art will recognize that many microprocessors include additional functionality (e.g., digital signal processing functions, data encryption functions, etc.) that are not explicitly described here. Such lack of explicit disclosure should not be construed as limiting. To the contrary, it will be readily apparent to those skilled in the art that such functionality is inherent to processing functions of many modern microprocessors, including the ones described herein.

[0040] Microprocessor 341 may be configured to receive data from one or more of gyroscope 343, accelerometer 344, and magnetometer 345, and transmit the received data to one or more remote receivers. Accordingly, microprocessor 341 may be communicatively coupled (e.g., wirelessly (as shown in Fig. 3, or using a wireline protocol) to, for example, processing and display unit 350 and configured to transmit the orientation and position data received from one or more of gyroscope 343, accelerometer 344, and magnetometer 345 to processing and display unit 350, for further analysis. As illustrated in Fig. 3, microprocessor 341 may be powered by power supply 342, such as a battery, fuel cell, MEMs micro-generator, or any other suitable compact power supply.

Anatomic Registration

[0041] As explained, in order for system 300 to accurately estimate pose of the anatomy 310 and pose of the surgical instrument 330, it must the register the patient's anatomy in the operating room (OR) to establish the spatial relationship between the patient's actual position in the OR and the virtual model stored in the processor 350. Anatomic registration is a process of establishing this relationship so that all pose data can be transformed into a single coordinate system (e.g., a reference coordinate system). This disclosure contemplates using any registration algorithm known in the art to register the patient's anatomy to the virtual model such as surface/object matching, palpation of anatomic landmarks, and intra-operative imaging. The virtual model may be constructed from pre-operative 3D images such as CT scan, for example. This disclosure contemplates using any modelling algorithm known in the art to create the virtual anatomic model such as the segmentation and modeling techniques currently used to convert Digital Imaging and Communications in Medicine (DICOM) images acquired by CT or MRI to 3D models. The above described anatomic registration and 3D modeling allows the system to convert the pose information as derived from the sensors into the appropriate anatomically correct components and display it in an anatomically correct fashion. The term "virtual," is used herein to refer to a plane, vector, or coordinate system that exists as a mathematical or algorithmic representation within a computer software program.

[0042] One example process for anatomic registration is by attaching modules 340 to an elongate registration tool or pointer and either pointing or aligning the tool to certain bony landmarks. For example, system 300 may be configured to measure orientation of modules 340 while they are removably attached to an elongate registration tool that is aligned to specific cervical and lumbar landmarks. Alternatively, system 300 may be configured to measure the position of the tip of a pointer to which module 340 is removable attached as the pointer palpates certain bony landmarks such as the spinous processes or collects points on certain bony surfaces. Using geometrical relationships associated with the anatomical landmarks and/or surfaces, the information indicative of the orientation and position of modules 340 can be used to derive a coordinate space that is representative of the anatomy.

[0043] Another example process for registration uses intraoperative images (such as fluoroscopic X-rays) taken at known planes (A-P or lateral), in some cases with identifiable reference markers on the anatomy, and then virtually deforms/reshapes the virtual model to match the images.

[0044] It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed systems and methods for measuring orientation and position of an anatomy or surgical instrument in orthopedic arthroplastic procedures. Other embodiments of the present disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the present disclosure. It is intended that the specification and examples be considered as exemplary only, with a true scope of the present disclosure being indicated by the following claims and their equivalents.