A surgical system incorporating intraoperative fiducials for spinal CT navigation guidance and related methods and devices

Abstract

Disclosed herein are various implementations directed to systems, methods, and devices used to improve orthopedic surgeries. In some of the disclosed implementations, the systems, methods, and devices improve accuracy of a 3D model of the anatomy of a patient prior placing pedicle screw and similar devices when securing medical equipment to bone, such as when fusing vertebrae together or similar procedures.

Description

A SURGICAL SYSTEM INCORPORATING INTRAOPERATIVE FIDUCIALS FORSPINAL CT NAVIGATION GUIDANCE AND RELATED METHODS AND DEVICESCROSS-REFERENCES TO RELATED APPLICATION(S)

[0001] This application claims the benefit under 35 U.S.C. § 119(e) to U.S. Provisional Application 63 / 691 ,854, filed September 6, 2024, and entitled “A SURGICAL SYSTEM INCORPORATING INTRAOPERATIVE FIDUCIALS FOR SPINAL CT NAVIGATION GUIDANCE AND RELATED METHODS AND DEVICES,” which is hereby incorporated by reference in its entirety for all purposes.TECHNICAL FIELD

[0002] The disclosure relates to surgical care generally and spinal surgery specifically.BACKGROUND

[0003] There is a need in the art for an improvement of the current systems used for placement of medical devices, such as pedicle screws, during surgery, such as spinal fusion surgery. One current practice involves conducting an intraoperative computed tomography ("CT") scan to be coupled with a computer based 3-dimensional (“3D”) navigation platform, which allows surgeons to use tracked instruments to identify the anatomy captured in the CT scan. A surgeon then assesses 3D navigation accuracy by placing the tracked instrument on an identifiable landmark and comparing where the 3D navigation system places that instrument on the anatomy model. This method has been utilized for placement of pedicle screws, allowing surgeons to visualize the screw trajectory on the 3D navigation platform, improving pedicle screw placement accuracy compared to use of X-ray assistance. For several reasons, such as changes in anatomy during surgery, this existing method contains some amount of inherent inaccuracy between the originally generated model and the position of the anatomy of the patient, which translates to risk for the patient. The technology disclosed herein answers the need for improved accuracy assessment and provides the ability to change 3D navigation registration without additional imaging in the art.#4853972BRIEF SUMMARY OF THE INVENTION

[0004] The various implementations disclosed herein are directed to a system for improving the accuracy of a surgical 3D navigation system throughout a surgery which may accommodate changes in anatomy or the relationship of the anatomy to the reference array through the use of surgeon created anatomic fiducials. In some of the implementations, the accuracy is improved through the use of one or more anatomic fiducials, a guidance probe, and a monitoring system to ensure sensitive areas of the patient are not damaged by when placing the pedicle screw or similar device due to inaccuracies in prior-generated models.

[0005] A system of one or more computers or computing devices may be configured to perform particular operations or actions by virtue of having software, firmware, hardware, or a combination of them installed on the system that in operation causes or cause the system to perform the actions. One or more computer programs may be configured to perform particular operations or actions by virtue of including instructions that, when executed by data processing apparatus, cause the apparatus to perform the actions.

[0006] Example 1 relates to a surgical navigation system comprising a computer- readable recording medium storing instructions in operational communication with a processor, the system configured to receive spatial data regarding the location of a medical tool in space and configured to receive imaging scan data and generate a 3D model of a bone of a patient from the imaging scan data, wherein the spatial data is used to superimpose a superimposed image of the medical tool onto the 3D model, wherein a location of the superimposed image of the medical tool may be compared to a location of a fiducial on the bone of a patient, and wherein a discrepancy between the location of the superimposed image of the medical tool and the location of the fiducial is used to update the 3D model.

[0007] Example 2 relates to Examples 1 and 3-7, wherein the computer-readable recording medium storing instructions is further configured to be in operational communication with a monitor in electronic communication with the processor and is configured to display the 3D model and superimposed image of the medical tool.

[0008] Example 3 relates to Examples 1 -2 and 4-7, wherein: a spatial reference frame is generated to quantify the spatial data, and a model reference frame is generated to quantify the 3D model.

[0009] Example 4 relates to Examples 1 -3 and 5-7, wherein the spatial reference frame and model reference frame are correlated to calculate the discrepancy.

[0010] Example 5 relates to Examples 1 -4 and 6-7, wherein the bone is a vertebra.

[0011] Example 6 relates to Examples 1 -5 and 7, wherein the fiducial is a small hole in the vertebra.

[0012] Example 7 relates to Examples 1 -6, wherein the system identifies the location of the fiducial automatically.

[0013] Example 8 relates to a surgical navigation system comprising a computer- readable recording medium storing instructions configured to be in operational communication with a processor, wherein the computer-readable recording medium storing instructions is configured to receive spatial data regarding the location of a medical tool in space and configured to receive a 3D model of a bone of a patient, wherein the spatial data is used to superimpose a superimposed image of the medical tool onto the 3D model, wherein the superimposed location of the medical tool may be compared to a location of a fiducial on the bone of a patient, and wherein a discrepancy between a location of the superimposed image of the medical tool and the location of the fiducial is used to update the 3D model.

[0014] Example 9 relates to Examples 8 and 10-14, wherein the computer-readable recording medium storing instructions is further configured to be in operational communication with a monitor in electronic communication with the processor and configured to display the 3D model and superimposed image of the medical tool.

[0015] Example 10 relates to Examples 8-9 and 1 1 -14, wherein a spatial reference frame is generated to quantify the spatial data, and wherein a model reference frame is generated to quantify the 3D model.

[0016] Example 1 1 relates to Examples 8-10 and 12-14, wherein the spatial reference frame and model reference frame are correlated to calculate the discrepancy.

[0017] Example 12 relates to Examples 8-11 and 13-14, wherein the medical tool is a guidance probe.

[0018] Example 13 relates to Examples 8-12 and 14, wherein the fiducial is a small hole in the bone.

[0019] Example 14 relates to Examples 8-13, wherein the 3D model is generated from a CT scan.

[0020] Example 15 relates to a surgical navigation system, comprising: a processor executing a computer-readable recording medium storing instructions configured to receive imaging scan data and generate a 3D model of a bone of a patient from the imaging scan data; and a monitoring system in electronic communication with the processor configured to gather spatial data regarding the location of a medical tool in space and convey the spatial data to the processor, wherein the spatial data is used to superimpose a superimposed image of the medical tool onto the 3D model, wherein the superimposed location of the medical tool may be compared to a location of a fiducial on the bone of a patient, and wherein a discrepancy between a location of the superimposed image of the medical tool and the location of the fiducial is used to update the 3D model.

[0021] Example 16 relates to Examples 15 and 17-20, further comprising a monitor in electronic communication with the processor and configured to display the 3D model and superimposed image of the medical tool.

[0022] Example 17 relates to Examples 15-16 and 18-20, wherein a spatial reference frame is generated to quantify the spatial data, and wherein a model reference frame is generated to quantify the 3D model.

[0023] Example 18 relates to Examples 15-17 and 19-20, wherein the spatial reference frame and model reference frame are correlated to calculate the discrepancy.

[0024] Example 19 relates to Examples 15-18 and 20, wherein the fiducial is a small hole in the bone.

[0025] Example 20 relates to Examples 15-19, wherein the fiducial comprises bone wax and a high contrast agent.

[0026] While multiple embodiments are disclosed, still other embodiments of the disclosure will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments of the invention. As will be realized, the disclosure is capable of modifications in various obvious aspects, allwithout departing from the spirit and scope of the disclosure. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive.BRIEF DESCRIPTION OF DRAWINGS

[0027] FIG. 1 is a diagram of an operating room employing the system, according to one implementation.

[0028] FIG. 2 is a diagram of a patient undergoing surgery with a reference array attached to patient anatomy, according to one implementation.

[0029] FIG. 3A is a diagram of the opening with a guidance probe in place, according to one implementation.

[0030] FIG. 3B is a diagram of a monitor showing the 3D model of the opening, according to one implementation.

[0031] FIG. 4 is an image of the opening with guidance probe in an anatomic fiducial, reference array attached to patient anatomy, according to one implementation.

[0032] FIG. 5A is a diagram of the opening with a guidance probe not aligned with an anatomic fiducial, according to one implementation.

[0033] FIG. 5B is a diagram of a monitor showing the 3D model of the opening with the guidance probe not aligned with an anatomic fiducial, according to one implementation.

[0034] FIG. 6A is a diagram of the opening with a guidance probe aligned with an anatomic fiducial, according to one implementation.

[0035] FIG. 6B is a diagram of a monitor showing the 3D model of the opening with the guidance probe incorrectly not aligned with an anatomic fiducial, according to one implementation.

[0036] FIG. 7 is a diagram of the 3D model with a superimposed medical device, according to one implementation.

[0037] FIG. 8 shows the 3D model with the model reference frame overlayed, according to one implementation.

[0038] FIG. 9 shows the guidance probe placed in a fiducial with the spatial reference frame overlayed, according to one implementation.

[0039] FIG. 10 shows the tracking points in the spatial reference frame being correlated to the model reference frame, according to one implementation.

[0040] FIG. 1 1 shows the spatial reference frame being correlated to the model reference frame, according to one implementation.

[0041] FIG. 12 shows the tip of the guidance probe in the spatial reference frame being correlated to the model reference frame, according to one implementation.

[0042] FIG. 13 shows a discrepancy between the expected position of the superimposed guidance probe to the measured position, according to one implementation.

[0043] FIG. 14 shows several reference frames being used for several vertebrae, according to one implementation.

[0044] FIG. 15 is a flowchart of how the system may determine a discrepancy between measured and expected values, according to one implementation.

[0045] FIG. 16 is a flowchart of a method of using the system, according to one implementation.

[0046] FIG. 17 is a flowchart of an operational method of using the system, according to one implementation.

[0047] FIG. 18 is an X-ray I CT scan of a patent with anatomic fiducials made in the vertebrae, according to one implementation.

[0048] FIG. 19A is an X-ray I CT scan of a patent with anatomic fiducials made in the vertebrae and guidance probe present, according to one implementation.

[0049] FIG. 19B is an X-ray I CT scan of a patent with anatomic fiducials made in the vertebrae and guidance probe present, according to one implementation.

[0050] FIG. 20A is an X-ray I CT scan of a patent with anatomic fiducials made in the vertebrae and guidance probe present, according to one implementation.

[0051] FIG. 20B is an X-ray I CT scan of a patent with anatomic fiducials made in the vertebrae and navigation guidance probe present, according to one implementation.DETAILED DESCRIPTION

[0052] Posterior spine instrumentation accounts for a very large portion of all spine surgery, which has led to numerous methods for placement of anchoring screws and other hardware. Spine instrumentation accuracy has been improved using intraoperative cross-sectional imaging for 3-dimensional surgical navigation. Misplacedpedicle screws may result in immediate complications such as neurologic injury, durotomy, vascular injury, and adjacent tissue injury. This disclosure contains various implementations that provide a solution to this problem. Additionally, the technology contained in this disclosure may be suitable for numerous other applications where a model of the anatomy of a patient may become misaligned with the true position of the anatomy, and where the realignment of the model and anatomy are advantageous.

[0053] The technology disclosed herein contains a surgical navigation system 10 for medical treatment, such as posterior spinal instrumentation surgery performed via the incision of the patient body to create a surgical opening, along with various related methods and devices.

[0054] Various implementations of the system 10, such as that of FIG. 1 , take place in a surgical theater or operating room. The system 10 may use 3D modeling systems to allow the staff of the operating room to see and track patient anatomy before, during, and after surgery. Some implementations of the system 10 employ a monitoring system 12 to track the various tools and anatomy of the patient in real-time. The monitoring system 12 may include an overhead camera 14 to optically track objects, a processor 16 to process data, and a monitor 18 to display information to staff, as well various ancillary equipment that may be required for operation. In certain implementations, the surgical navigation system 10 comprises computer-readable recording medium storing instructions in operational communication with the monitoring system 12, as would be readily appreciated.

[0055] In other implementations, the monitoring system 16 may use electromagnetic navigation system rather than optical systems. While this disclosure refers primarily to optical implementations of the monitoring system 16, it would be understood by those in the art that any object location technology that is compatible with the other components of the system 10 may be used.

[0056] In various implementations, the processor 16 may be any device configured to operate computer-readable recording medium storing instructions and intake data, perform calculations and manipulations of that data, and make outputs and commands. The system 10 may also use an imaging scanner (not shown) to create images such as cross-sectional images of the patient in the region of interest. This imaging data fromthe imaging scans may be used by the system 10 to construct a 3D model 38, which may be displayed on the monitor 18. In various implementations, the imaging scanner may take medical scans such as a computed tomography (CT) X-ray, magnetic resonance imaging ("MRI"), or other similar technology known in the art. While all of these imaging technologies are compatible with the system 10, CT scans will be discussed in the exemplary implementations described herein, which is in no way intended to be limiting.

[0057] In various implementations, the system 10 may also have a guidance probe 20 with a shaft 22 and one or more tracking points 24. As would be understood, the overhead camera 14 may be configured to monitor objects in or near the opening 26 and display those objects in relation to the 3D model on the monitor 18. The objects, in various implementations, may be a medical tool 20 such as the guidance probe 20. The tracking points 24 on the guidance probe 20 may allow the overhead camera 14 to track the guidance probe 20 orientation more accurately, as position, rotation, and tilting may be determined by the relative position of the tracking points 24. In various implementations, the guidance probe 20 may also have a tip 36 at the end of the shaft 22 opposite of the tracking points 24, as will be discussed in more detail below. In various implementations, such as shown in FIG. 2, a reference array 25 may be affixed to the anatomy of the patient, such as to a bone 28 or vertebra 28. The reference array 25 may have a plurality of reference points 27 that may be located by the monitoring system 12, such as with the overhead camera 14. The location of the reference points 27, in various implementations, may be used to determine the relative position of the tracking points 24 in space, whereby the location and orientation of the guidance probe 20 may be determined.

[0058] As would be understood, determining the precise location of the medical tools such as the guidance probe 20 from objects outside or above the surgical opening 26 is useful, as the overhead camera 14 may not always have a clear line of sight into all areas of the opening 26.

[0059] While the system 10 may be applied in numerous and varied surgical applications, one exemplary application is in placing pedicle screws during a spinalfusion surgery. FIG. 2 shows the opening 26 of a patient where the posterior elements of the vertebra 28 are exposed in the opening 26 prior to spinal instrumentation.

[0060] As would be understood, traditional surgical techniques for assessing accuracy of a 3D model 38 (discussed below) of the opening 26 involve placing tip of the guidance probe 20 near an anatomic landmark on the vertebrae 28 of the patient and comparing it to where the 3D navigation system 12 computes that the tip 36 (discussed below) of the guidance probe 20 is on the anatomic 3D model 38 displayed on the monitor 18. The position of the guidance probe 20 may be detected by the overhead camera 14 due to the overhead camera 14 being able to see the tracking points 24.

[0061] As shown in FIGS. 3A and 3B, in various implementations of the system 10, an anatomic fiducial 30, or fiducial 30, may be placed on or made in the bone which is to be positioned and modeled. The fiducials 30 may be small, shallow holes created in the hemilamina of the vertebrae 28 of a patient. In various implementations, the fiducials 30 are made with a small drill, such as a 3 mm drill, although other sizes are of course possible. The fiducials 30 may also only penetrate the outer cortical bone of the vertebrae 28, so as to minimize risk to the patient. Alternatively, the fiducials 30 may be objects secured to the surface of the bone 28 or vertebrae 28 that is detectable by an imaging scan, such as a CT scan. In one exemplary implementation, the fiducials may be made of bone wax mixed with a high contrast agent, i.e. a compound designed to stand out distinctly from the background of an imaging scan. Various other methods of forming or placing fiducials 30 are possible, as long as the fiducials 30 are visible on an imaging scan and are visible to surgeons and staff. In various implementations, the fiducials 30 are automatically detected through the imaging scan. In other implementations, the fiducials 30 may be manually placed within a 3D model.

[0062] In various implementations of the system 10, the 3D model created using imaging scan data and data from the overhead camera 14 may be periodically checked for accuracy to ensure the model accurately shows the positions of anatomy of the patient, such as vertebrae 28, as will be discussed in detail below. FIG. 3A shows the opening 26 where fiducials 30 have been made in the vertebrae 28, as may be seen from the point of view the operating surgeon or surgeons. FIG. 3B shows a display of the 3D model on the monitor 18 that may be referenced by the surgeon or surgeons toensure medical equipment, such as pedicle screws, do not align with sensitive regions of the spine, such as the spinal cord, before insertion.

[0063] FIG. 4 shows an image of the opening 26 with fiducials 30 made in the vertebrae 28 of the patient, and with the guidance probe 20 placed in one of the fiducials 30.

[0064] FIGS. 5A and 5B show how the placement of the tip 36 of the guidance probe 20 relative to the vertebrae 28 resulting in the image of the guidance probe 20 shifting accordingly in the 3D monitor, according to various implementations. However, in some implementations, the position of the guidance probe 20 is determined by the overhead camera 14 data, rather than data from an imaging scan. Under ordinary circumstances, the position of tools like the guidance probe 20 relative to the overhead camera 14 and relative to the vertebrae 28 of the patient should remain unchanged. However, because the vertebrae 28 may shift relative to one another during surgery, and because various other issues with model calibration and model drift may occur, it occasionally becomes the case that the physical placement of a tool, like the guidance probe 20, does not correspond to the placement of the image of the tool in the 3D model 38. This is shown in FIGS. 6A and 6B.

[0065] FIG. 6A shows the placement of the tip 36 of a guidance probe 20 in a fiducial 30 as would be seen from the point of view of the surgeon. FIG. 6B shows the 3D model 38 with the guidance probe 20 superimposed onto model, but some change in relationship of the anatomy to reference array has changed from the time of CT scan such that image of the guidance probe 20 relative to the model is no longer accurate. In various implementations of the system 10, the monitor 18 or processor 16 or other component of the monitoring system 12 may have a prompt button 32 that may alert the processor 16 that the guidance probe 20 is inserted into a fiducial 30 and a recalibration is needed. In these implementations, the processor 16 may determine which fiducial 30 in the 3D model 38 is nearest to the image of the guidance probe 20 in the 3D model 38 and may adjust the position of the 3D model 38 to correct for differences in the measured position of the fiducial 30 and the expected position of the fiducial 30. As would be understood, this method does not require an intraoperative imaging scan to correct for deviations in the model, although in various implementations intraoperative imaging scans may be used in combination with the fiducial 30 correction technique.Once the processor 16 has updated the 3D model 38 to incorporate the new calibration data from the placement of the guidance probe 20, the 3D model 38 and guidance probe 20 placement may resemble that of FIGS. 3A and 3B again.

[0066] In various implementations, such as shown in FIG. 7, once the model of the vertebrae 28 has been corrected for drift, the surgeon may proceed with placing a medical device 34, such as a pedicle screw 34, with confidence that the orientation of the medical device displayed on the monitor 18 is accurate.

[0067] Various implementations of the system 10 may have automated systems to correct a 3D model 38 for deviations detected.

[0068] In various implementations, such as is shown in FIG. 8, the system 10 may have a 3D model 38, optionally based on the data, such as CT scan data, from the imaging scanner. In various implementations discussed herein, this data used to construct the 3D model 38 may be called model data 40. The system 10, optionally the processor 16 within the system 10, may process the model data 40 and assign a model reference frame 42 that corresponds to the geometry of the model. In various implementations, the model reference frame 42 has its position and orientation fixed to the 3D model 38 and not to any physical position of the bone 28. As would be understood, the orientation of models and references frames may be determined in various ways, such as coordinate systems, known in the art. This disclosure will discuss locations in a three- dimensional Cartesian coordinate system, although this is only illustrative and not restrictive, as other systems to track orientation of models and references frames may be used.

[0069] Turning to FIG. 9, in various implementations, the monitoring system 12 may track the location of the tracking points 24 of the guidance probe 20, which may allow the monitoring system 12 to determine the location of the guidance probe 20, as well as the orientation of the guidance probe 20, in real space. In various implementations, the location and orientation of the guidance probe 20 in space is tracked by analyzing spatial data 44 constructing a spatial reference frame 46 in the field of view of the monitoring system 12. In various implementations, the spatial data 44 is collected through optical instruments, such as the overhead camera 14, or through electromagnetic navigation systems. As would be understood, the location of objects inspace may be determined in various ways, such as coordinate systems, known in the art. This disclosure will discuss locations in a three-dimensional Cartesian coordinate system, although this is only illustrative and not restrictive, as other systems to track location may be used.

[0070] FIG. 10 shows a display of the 3D model 38 with the guidance probe 20 superimposed, as might be displayed on the monitor 18. In various implementations, the system 10 may establish a baseline relationship between the model reference frame 42 and the spatial reference frame 46. In some implementations, this may be done by correlating the position of the tracking points 24 to some point on the model reference frame 42 with positions of the tracking points 24 that correspond to the tip 36 of the guidance probe 20 being placed in a fiducial 30.

[0071] In other implementations, such as in FIG. 11 , the model reference frame 42 and spatial reference frame 46 may be correlated by relationships between some defined point within each reference frame, such as an origin point, that indicate the tip 36 of the guidance probe 20 is in a fiducial 30. In some implementations, such an origin point of the spatial reference frame 46 would require additional dimensional data, such as orientation data, which may make the origin point fourth dimensional or higher.

[0072] In still other implementations, such as in FIG. 12, the model reference frame 42 and spatial reference frame 46 may be correlated by determining the location of the tip 36 of the guidance probe 20 relative to the model reference frame 42. As above, in some implementations, the location information of the tip 36 may require more than three dimensions to fully convey the location and orientation of the guidance probe 20.

[0073] Various other strategies may be employed in correlating the model reference frame 42 to the spatial reference frame 46 such that the physical location of the guidance probe 20 may be superimposed onto the 3D model 38.

[0074] In some implementations, such as in FIG. 13, when the guidance probe 20 is placed in the fiducial 30, the superimposed location of the guidance probe 20 on the 3D model 38 may display a different location of the guidance probe 20 relative to the 3D model 38. As would be understood, this difference in location may be caused by shifts in the anatomy of the patient during surgery or movement of the reference array attached to patient anatomy which cannot be accounted for without some intervention.This difference between the expected position of the superimposed guidance probe 20 on the model reference frame 42 and the measured position may be called a discrepancy 48. In various implementations, the system 10 may use the discrepancy 48 value to adjust the 3D model 38 appropriately for the new position of the bone 28, as indicated by the new position of the guidance probe 20 when placed in the fiducial 30.

[0075] In various implementations, such as is displayed in FIG. 14, each bone 28 may be assigned a different model reference frame 42A, 42B, 42C. Each individual model reference frame 42A, 42B, 42C may be adjusted relative to one another to reflect changes in bone 28 position relative to other bones 28.

[0076] FIG. 15 shows a flowchart of a method 100 on how the system 10 may automatically adjust for a discrepancy 48 between the model reference frame 42 and the spatial reference frame 46, according to various implementations. Note that the order and presence of each of these steps, and all steps in this disclosure, is simply illustrative and is not meant to be restrictive. Each of the disclosed steps may be omitted, altered, or reordered as determined to be necessary by those skilled in the art. The method 100 may either create a 3D model 38 from medical imaging data, such as but not limited to data from a CT scan or may receive the 3D model 38 from an external source (box 102). The system 10 may then overlay the model reference frame 42 or several model reference frames 42A, 42B, 42C onto the 3D model 38 (box 104).

[0077] In various implementations of the method 100, the system 10 may receive spatial data 44, either from an outside source or from an overhead camera 14 on an integrated monitoring system 12 (box 106). The system 10 may then overlay the spatial reference frame 46 onto the data 44, such as by converting raw imaging data into spatial reference coordinates, or by other methods known in the art (box 108). The system 10 may then create a correlation, relationship structure, or mathematical function between the model reference frame 42 and the spatial reference frame 46 such that the position of objects measured relative to the spatial reference frame 46 may be calculated or estimated in the model reference frame 42 and vice versa (box 110).

[0078] In various implementations, the system 10, when performing the method 100, may be prompted (box 1 12) to check the position of objects relative to the model reference frame 42 to determine if there is discrepancy 48 between 3D model 38 andthe position of the relevant bone 28 or bones 28 (box 114). Alternatively, the system 10 may check for a discrepancy 48 without being prompted, but instead constantly calculate the position of the tracking points 24 and update the model, if necessary, when the tracking points are in a position that would correspond to the guidance probe 20 being placed in a fiducial 30.

[0079] The system 10 may then adjust the 3D model 38 and model reference frame 42 accordingly to ensure the 3D model 38 accurately represents the present position of the relevant bone 28 or bones 28. In various implementations, the 3D model 38 and model reference frame 42 may be adjusted by translating and rotating the 3D model within the model reference frame 42 such that the fiducial 30 nearest the superposed tip 36 of the guidance probe 20 is aligned with the guidance probe 20 tip 36, as would be the expected position.

[0080] Various implementations of the system 10 include a surgical method 100 for ensuring surgical accuracy throughout a medical procedure. FIG. 16 shows a flowchart of some implementations of such a surgical method 200. The surgical method 200 may begin by placing or setting anatomic fiducials 30 in a bone 28 of a patient (box 102). The surgical method 200 may include imaging the opening 26 (box 204) and constructing a 3D model of the opening 26 (box 206) and the locations of the fiducials 30. The surgeon performing the surgical method 200 may then place the guidance probe 20 into a fiducial 30 on a relevant bone 28 (box 208). The surgeon may then refer to the monitor 18 to ensure the placement of the image of the guidance probe 20 is accurate (box 210). If the guidance probe 20 is not shown in the proper position on the 3D model, the surgeon may prompt the system 10 to recalibrate the model (box 212), after which the guidance probe may be positioned (box 208) and checked (box 210) again. If the guidance probe 20 position in the 3D mode is accurate, the surgeon may proceed with inserting a medical device 341 pedicle screw 34 into the bone 28 (box 214). The surgeon may then proceed to other bones 28 as may be required (box 216).

[0081] Various implementations of the system 10 may also include an operational method 300, where the fiducials 30 have already been placed in the bones 28 of a patient and a 3D model of the anatomy of the patient has already been generated, such as shown in FIG. 17. The operational method 300 may begin by placing the guidanceprobe 20 in a fiducial 30 on the relevant bone (box 302). The surgeon may then refer to the monitor 18 to ensure the placement of the image of the guidance probe 20 is accurate (box 304). If the guidance probe 20 is not shown in the proper position on the 3D model, the surgeon may prompt the system 10 to recalibrate the model (box 306), after which the guidance probe may be positioned (box 302) and checked (box 304) again. If the guidance probe 20 position in the 3D mode is accurate, the surgeon may proceed with inserting a medical device 341 pedicle screw 34 into the bone 28 (box 308). The surgeon may then proceed to other bones 28 as required (box 310).

[0082] FIG. 18 shows a CT scan of a patient where the fiducials 30 are detectable, as would be seen in various implementations. Similarly, FIGS. 19A and 19B show the guidance probe 20 superimposed on the 3D model of a patient. FIG. 19A shows the model in the transverse plane, and FIG. 19B shows the model in the coronal plane. As would be understood, displaying the model from intersecting planes in this manner allows for the accurate location of tools in 3D space.

[0083] FIGS. 20A and 20B also show the guidance probe 20 superimposed on the 3D model, however the position of the guidance probe 20 does not align with the

[0084] As would be understood, the presently disclosed technology is a powerful tool to use in the operating room which may allow for more accurate pedicle screw placement when used properly. A major benefit of this technology over the prior art is the ability to update a 3D model 38 of the anatomy of a patient without the need for an intraoperative imaging scan, such as an intraoperative CT scan. As would be understood, performing an intraoperative imaging scan to update a 3D model 38 of the anatomy of a patient may be time consuming and cumbersome, especially considering the criticality of time efficiency in a surgical setting.

[0085] This technology whereby small anatomic fiducials are created within each vertebra of the exposed spine during traditional, open, posterior approach surgery prior to surgery allows a surgeon to quickly and effectively assess 3D navigation accuracy with greater discretion than traditional comparison to known anatomic landmarks as well as quickly and accurately correct for inaccuracies in the 3D model 38.

[0086] This technology also does not add an appreciable amount of time to the surgery, as the alignment is able to be performed in a matter of seconds. Further, because thefiducials 30 may only penetrate the cortical bone of the vertebrae 28, the risk of complications from the placement of the fiducials 30 is minimized.

[0087] As would be understood, an additional benefit of this technology is that it allows an operator of the system 10 to check accuracy at each individual spinal level as a reference point is created near each ideal screw entry point. In patients who have undergone previous surgery that have distorted normal anatomy, this technology proves very useful, as an anatomic fiducial 30 may be placed on any available bone 28, regardless of whether it is representative of any anatomic feature.

[0088] Additionally, because the fiducials 30 are generally small markers, they may provide increased imaging accuracy in comparison to traditional anatomic landmarks due to more precise tool placement.

[0089] As would be understood, this technology may be used in a variety of surgeries, including surgeries on all portions of the spine and the skeleton more broadly. However, this technology shows particular usefulness in surgeries on the cervical spine, as the cervical spine is generally smaller than the thoracic and lumbar spine, in addition to being positioned adjacent to the vertebral artery. This is compounded by the fact that the cervical spine is more mobile than the thoracic and cervical spine. Additionally, the anatomic landmarks of the cervical spine are not as pronounced as in the thoracic and cervical spine, increasing the need for a more proximate marker.

[0090] Although the disclosure has been described with reference to preferred embodiments, persons skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the disclosed apparatus, systems and methods.

Claims

CLAIMSWhat is claimed is:1 . A surgical navigation system comprising a computer-readable recording medium storing instructions in operational communication with a processor, the system configured to receive spatial data regarding the location of a medical tool in space and configured to receive imaging scan data and generate a 3D model of a bone of a patient from the imaging scan data, wherein the spatial data is used to superimpose a superimposed image of the medical tool onto the 3D model, wherein a location of the superimposed image of the medical tool may be compared to a location of a fiducial on the bone of a patient, and wherein a discrepancy between the location of the superimposed image of the medical tool and the location of the fiducial is used to update the 3D model.

2. The system of claim 1 , wherein the computer-readable recording medium storing instructions is further configured to be in operational communication with a monitor in electronic communication with the processor and is configured to display the 3D model and superimposed image of the medical tool.

3. The system of claim 1 , wherein:(a) a spatial reference frame is generated to quantify the spatial data, and(b) a model reference frame is generated to quantify the 3D model.

4. The system of 3, wherein the spatial reference frame and model reference frame are correlated to calculate the discrepancy.

5. The system of claim 1 , wherein the bone is a vertebra.

6. The system of claim 5, wherein the fiducial is a small hole in the vertebra.

7. The system of claim 1 , wherein the system identifies the location of the fiducial automatically.

8. A surgical navigation system comprising a computer-readable recording medium storing instructions configured to be in operational communication with a processor, wherein the computer-readable recording medium storing instructions is configured to receive spatial data regarding the location of a medical tool in space and configured to receive a 3D model of a bone of a patient, wherein the spatial data is used to superimpose a superimposed image of the medical tool onto the 3D model, wherein the superimposed location of the medical tool may be compared to a location of a fiducial on the bone of a patient, and wherein a discrepancy between a location of the superimposed image of the medical tool and the location of the fiducial is used to update the 3D model.

9. The system of claim 8, wherein the computer-readable recording medium storing instructions is further configured to be in operational communication with a monitor in electronic communication with the processor and configured to display the 3D model and superimposed image of the medical tool.

10. The system of claim 8, wherein a spatial reference frame is generated to quantify the spatial data, and a model reference frame is generated to quantify the 3D model.1 1 . The system of claim 10, wherein the spatial reference frame and model reference frame are correlated to calculate the discrepancy.

12. The system of claim 8, wherein the medical tool is a guidance probe.

13. The system of claim 8, wherein the fiducial is a small hole in the bone.

14. The system of claim 8, wherein the 3D model is generated from a CT scan.

15. A surgical navigation system, comprising:(a) a processor executing a computer-readable recording medium storing instructions configured to receive imaging scan data and generate a 3D model of a bone of a patient from the imaging scan data; and(b) a monitoring system in electronic communication with the processor configured to gather spatial data regarding the location of a medical tool in space and convey the spatial data to the processor, wherein the spatial data is used to superimpose a superimposed image of the medical tool onto the 3D model, wherein the superimposed location of the medical tool may be compared to a location of a fiducial on the bone of a patient, and wherein a discrepancy between a location of the superimposed image of the medical tool and the location of the fiducial is used to update the 3D model.

16. The system of claim 15, further comprising a monitor in electronic communication with the processor and configured to display the 3D model and superimposed image of the medical tool.

17. The system of claim 15, wherein a spatial reference frame is generated to quantify the spatial data, and a model reference frame is generated to quantify the 3D model.

18. The system of claim 17, wherein the spatial reference frame and model reference frame are correlated to calculate the discrepancy.

19. The system of claim 15, wherein the fiducial is a small hole in the bone.

20. The system of claim 15, wherein the fiducial comprises bone wax and a high contrast agent.

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