WO2016086041A1

WO2016086041A1 - Patient-specific trackable soft tissue cutting guides

Info

Publication number: WO2016086041A1
Application number: PCT/US2015/062507
Authority: WO
Inventors: Gerald GRANT; Peter LIACOURAS; Chad GORDON; Ryan Murphy; Mehran Armand
Original assignee: The Johns Hopkins University
Priority date: 2014-11-24
Filing date: 2015-11-24
Publication date: 2016-06-02

Abstract

Provided is a patient-specific trackable soft tissue cutting guide for guiding a soft-tissue incision path that includes: a body, wherein the body comprises at least one surface that substantially corresponds to contours of at least one preselected soft-tissue portion of a being's anatomy; and at least one trackable element extending from the body.

Description

PATIENT-SPECIFIC TRACKABLE SOFT TISSUE CUTTING GUIDES

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Patent Application Ser. No.

62/199,095 entitled "Patient-Specific Trackable Soft Tissue Cutting Guides" filed on July 30, 2015, the entirety of which is incorporated herein by reference, and to Patent Cooperation Treaty Application Ser. Nos. PCT/US 14/67167 entitled "Cranial Reference Mount" filed on November 24, 2014, PCT/US 14/67174 entitled "Patient-Specific Trackable Cutting Guides" filed on November 24, 2014, PCT/US 14/67504 entitled "Computer-Assisted Face- Jaw-Teeth Transplantation" filed on November 25, 2014, PCT/US 14/67656 entitled "Computer-Assisted Craniomaxillofacial Surgery" filed on November 26, 2014, PCT/US 14/67671 entitled "Computer-Assisted Planning and Execution System" filed on November 26, 2014, PCT/US 14/67581 entitled "Orthognathic Biomechanical Simulation" filed on November 26, 2014, and PCT/US 14/67692 entitled "Real-Time Cephalometry For Craniomaxillofacial Surgery" filed on November 26, 2014, the entireties of which are incorporated herein by reference.

GOVERNMENT RIGHTS

[0002] This disclosure was made with Government support under Contract No. NCATS

Grant No. UL1TR000424-06 awarded by the National Institutes of Health. The Government has certain rights in the invention.

FIELD

[0003] This disclosure is generally directed to surgery, particularly craniomaxillofacial surgery, and specifically to the field of computer-assisted craniomaxillofacial surgery and all related orthognathic, neurosurgical and head/face/neck surgical procedures and associated methods, tools and systems.

BACKGROUND

[0004] The reconstruction of severe midfacial defects was revolutionized by the introduction of Le Fort-based, face-jaw-teeth transplantation in 2008. Since then, a number of face-jaw-teeth transplantations have been reported. Recent face-jaw-teeth transplantations demonstrate improved patient survival and enhanced aesthetics; however, post-transplant results seen to date achieve only class II or III skeletal relation, with significant malocclusion, suboptimal masticatory function, dentofacial disharmony, and palatal defects between the donor/recipient maxillary segments.

[0005] Post-face-jaw-teeth transplantation occlusal outcomes have been investigated for

Le Fort-based allotransplantation to describe "hybrid occlusion." Hybrid occlusion is the result of the posttransplant relation between two human jaws of varying anthropometrics (i.e., a native jaw and an allograft jaw). Although hybrid malocclusion and poor facial skeletal relationship may be prevented with adequate planning, they are often considered important only after transplantation. Many face-jaw-teeth transplantations require dentoskeletal adjustments, which create the high possibility of debilitating malocclusion, incomplete palates, potential malocclusion- related facial pain, and need for revision surgery.

[0006] The intraoperative use of dental casts, "hybrid splints," and other intraoral orthognathic devices in face-jaw-teeth transplantation may potentially improve post-face-jaw- teeth transplantation hybrid occlusion, facial projection, and skeletal harmony. However, these devices pose numerous shortcomings. Fabrication of these components is very time consuming considering the time-sensitive transplant timeframe; generally, face-jaw-teeth transplantation occurs within 24 to 36 hours of donor identification. Moreover, both device fabrication and operation require access to dental specialists (maxillofacial prosthodontists and oral/maxillo facial surgeons), which may be difficult given the time constraint. As is often the case with any form of orthognathic surgery, unexpected intraoperative adjustments of the surgical plan may be required based on many factors, including osteotomy success, unexpected dental caries, or soft-tissue/masticatory muscle hindrance. These intraoperative obstacles may significantly diminish the value of prefabricated occlusal splints. For instance, the first reported face-jaw-teeth transplantation in 2008 required extracting all donor teeth (except for the central incisors) because of extensive caries found on radiographic evaluation. In addition, conventional dental devices may not account for the lateral orbital (frontozygomatic) and/or nasofrontal donor tissue positioning, both of which are critical sites for rigid fixation.

[0007] What is needed in the art are systems, methods and tools for overcoming the challenges described above

SUMMARY

[0008] In an embodiment, there is a patient-specific trackable soft tissue cutting guide for guiding a soft-tissue incision path, comprising: a body, wherein the body comprises at least one surface that substantially corresponds to contours of at least one preselected soft-tissue portion of a being's anatomy; and at least one trackable element extending from the body.

[0009] In another embodiment, there is a method for fabricating a patient-specific trackable soft tissue cutting guide, comprising: accessing a computer-readable representation of an anatomical feature; superimposing a cut-plane on the computer-readable representation of the anatomical feature, wherein an interface between the cut-plane and the computer-readable representation of the anatomical feature defines a geometry; and generating a computer-readable representation of a cutting guide comprising at least one surface that substantially corresponds to at least a portion of the geometry..

[0010] In another embodiment, there is a surgical method, comprising: attaching a first reference unit comprising a first trackable element to a first anatomical feature of a being; placing a trackable soft-tissue cutting guide on a second anatomical feature of the being, wherein the trackable soft-tissue cutting guide comprises a body and at least one surface that substantially conforms to a portion of the second anatomical feature of a being, at least one edge portion that defines an incision path on the being, and at least one trackable element extending from the body..

[0011] Additional advantages of the embodiments will be set forth in part in the description which follows, and in part will be understood from the description, or may be learned by practice of the invention. The advantages will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.

[0012] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.

[0013] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIGS. 1A-C provide a schematic overview of a computer-assisted surgical system. [0015] FIGS. 1D-1H are graphical reconstructions of some components and/or features of the surgical system of FIGS. 1A-1C.

[0016] FIG. 2A illustrates a computer-readable reconstruction of a donor's anatomy including planned cutting planes superimposed thereon.

[0017] FIG. 2B illustrates an illustrative surgical guide assembly coupled to a skull.

[0018] FIGS. 2C-2E show steps of a transplantation procedure in which a

[0019] FIG. 3 A shows a patient-specific, trackable soft-tissue cutting guide in use for marking an incision path on an anatomical feature of a being.

[0020] FIG. 3B shows an example of an incision path formed with the assistance of a user-customized, trackable soft-tissue cutting guide. Here, the incision path is marked on a donor being along the cheek and lower facial region in the area of planned donation.

[0021] FIG. 3C shows an initial soft tissue dissection performed on the donor at the level of all soft tissue including all pertinent neurovascular structures.

[0022] FIG. 4 is a flow chart representative of a method for fabricating a patient-specific, trackable soft-tissue cutting guide.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] Reference will now be made in detail to the present embodiments, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

[0024] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements. Moreover, all ranges disclosed herein are to be understood to encompass any and all sub-ranges subsumed therein. For example, a range of "less than 10" can include any and all sub-ranges between (and including) the minimum value of zero and the maximum value of 10, that is, any and all sub-ranges having a minimum value of equal to or greater than zero and a maximum value of equal to or less than 10, e.g., 1 to 5. In certain cases, the numerical values as stated for the parameter can take on negative values. In this case, the example value of range stated as "less that 10" can assume negative values, e.g. -1, -2, -3, - 10, -20, -30, etc.

[0025] The following embodiments are described for illustrative purposes only with reference to the Figures. Those of skill in the art will appreciate that the following description is exemplary in nature, and that various modifications to the parameters set forth herein could be made without departing from the scope of the present invention. It is intended that the specification and examples be considered as examples only. The various embodiments are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments.

[0026] Disclosed are embodiments of a computer-assisted surgery system that provides for large animal and human pre-operative planning and intraoperative navigation which includes trackable surgical cutting guides, and dynamic, real-time instantaneous feedback of cephalometric measurements/angles as needed for medical procedures, such as facial transplantation, and many other instances of craniomaxillofacial and orthognathic surgery. Such a system can be referred to as a computer-assisted planning and execution (C.A.P.E.) system and can be exploited in complex craniomaxillofacial surgery like Le Fort-based, face-jaw-teeth transplantation, for example, and any type of orthognathic surgical procedure affecting one's dental alignment, and can include cross-gender facial transplantation. [0027] The fundamental paradigm for computer-assisted surgery (CAS) involves developing a surgical plan, registering the plan and instruments with respect to the patient, and carrying out the procedure according to the plan. Embodiments described herein include features for workstation modules within a CAS paradigm. A system and corresponding methods for tracking donor and recipient surgical procedures simultaneously are described. The methods rely on the use of a computer-assisted surgery system.

[0028] A patient-specific, trackable soft-tissue cutting guide may be either supplied by a third- party vendor, printed with an additive or subtractive manufacturing device, such as a 3D printer, that receives instructions generated provided by a system of the embodiments, as described below, so that a custom patient-specific, trackable soft-tissue cutting guide is available to the surgeon and placed utilizing feedback from the CAPE system to achieve ideal positioning and alignment to the native anatomy. An embodiment of the CAPE system described above can be used to provide the clinician with real-time visual feedback as to the ideal positioning of the patient-specific, trackable soft-tissue cutting guide (i.e. planned versus actual). Also, the CAPE system can access computer-readable reconstructions of a being's anatomy, such as computer- readable files containing soft tissue, vasculatory and/or skeletal CT scan data, which may be uploaded ahead of time into a memory of a computer of the CAPE system, and which can be utilized to by a clinician for predicting a patient's appearance during and after surgery.

[0029] In general, features of such a CAPE system can include: 1) two or more networked workstations concurrently used in planning and navigation of the two simultaneous surgeries for both donor and recipient irrespective of geographic proximity, 2) two or more trackers, such as electromagnetic trackers, optical trackers (e.g., Polaris, NDI Inc.), and the like, for tracking trackable elements incorporated or attached to anatomical features such as bone fragments and soft tissue; surgical tools, navigation and reference markers, and 3) cutting guides, reference kinematic markers, and other registration tools to which trackable elements can be attached or incorporated, as required for navigation to direct proper placement of donor fragments/tissues on a recipient. The use and fabrication of patient-specific (i.e., patient- customized or custom made) trackable soft tissue cutting guides can be incorporated in systems and methods for tracking donor and recipient surgical procedures simultaneously, particularly for use in guiding appropriate location for setting an incision path.

[0030] In general, preoperative planning includes performing segmentation and 3D reconstruction of recipient and donor CT scans. Virtual osteotomies can then be performed the use of software to match donor/recipient features. For example, during the initial planning stage, a virtual plan is determined based on the recipient's craniomaxillo facial deformity irrespective of the donor. From registered CT data, segmentation software generates volume data for specific key elements (e.g., the mandible, maxilla, and cranium) used for preoperative planning and visualization. A computer processor executes software instructions for automatically generating expected cut geometries of the donor fragment and of the recipient and placement of the donor fragment onto the recipient. As such, a surgical method can include determining predicted resulting transplanted anatomical features with accompanying hybrid occlusion, for example, via generating computer readable representations of the recipient anatomy, donor anatomy, donor fragment, and hybrid anatomical feature comprising the donor fragment transplanted onto the recipient anatomy. Blood vessels of the donor, recipient, or both may also be segmented from CT angiography scans. For example, nerves (via known nerve formations) and vessels (both arteries and veins) can be localized to provide a full anatomical "road map" to the surgeons for a more precise, time-saving anatomical dissection with perhaps decreased blood loss and smaller incisions. Thus, preoperative planning can include, among many other steps, the following tasks: a) segmentation and volumetric reconstruction of the donor and recipient facial anatomy; b) planning for patient-specific cutting guide placement; c) cephalometric analysis and biomechanical simulation of the hybrid skeleton's occlusion and masticatory function, respectively; d) fabrication of trackable cutting guides; e) 3D mapping the vascular system on both recipient and donor facial anatomy; and f) plan updates, if necessary, based on the feedback from performing intraoperative tasks.

[0031] Intraoperative tasks of embodiments described herein can generally include: a) registering the preoperative model reconstructed from the CT data to donor and recipient anatomy; b) visualizing (e.g., using information from at least one of the trackers) the location/orientation of cutting guides, reference markers and anatomical features to help the surgeon navigate proper placement of such items; c) verifying the placement of cutting guides, and performing real-time cephalometric and biomechanical simulation for occlusion analysis, if, for any reason, the osteotomy sites need to be revised; d) dynamically tracking the attachment of the donor fragment to the recipient and providing quantitative and qualitative (e.g., visual) feedback to the surgeon for the purpose of improving final outcomes related to form (i.e., overall facial aesthetics) and function (i.e., mastication, occlusion relation, airway patency).

[0032] A computer-assisted surgical system may be utilized, for the pre-operative planning and intra-operative execution of a transplantation. For example, the anatomy of a recipient being, which may be a human being, may include an anatomical feature, such as a diseased portion of the anatomy, that requires removal or replacement with an transplanted anatomical feature, which may be harvested from the anatomy of a donor being. During a surgical procedure, the recipient's anatomical feature in question may be separated from the recipient being by cutting away from the recipient being's anatomy. Likewise, the donor's anatomical feature which will be transplanted to the recipient being may be separated from the donor being by cutting away from the recipient' being's anatomy.

[0033] To begin, a patient-specific (i.e., patient-customized or custom-made) trackable soft-tissue cutting guide may be used to provide a surgeon with a template around which an incision path may be marked. The surgeon may then place the patient-specific, trackable soft- tissue cutting guide on a portion of a being's anatomy. In an example, after performing intraoperative registration (in which contours of donor and/or recipient anatomy are digitized and real-time cephalometric calculations of anatomical relations are performed), a surgeon may place the soft-tissue cutting guides into an optimal position defined by preoperative planning and as tracked according to the intra-operative tasks described above. That is, a location of the soft- tissue cutting guide may be monitored by a tracker (such as an optical or magnetic sensor) relative to a reference unit placed on a known location of the being. For example, the soft-tissue cutting guide may include trackable elements which may be detected by a tracker, such as an optical or magnetic detector. Software executed by a processor of a computer which receives electrical signals from the tracker may operate to access computer-readable representations of anatomical features and/or computer-readable representations of the soft-tissue cutting guides. The computer-readable representations of the anatomical features and/or the computer-readable representations of the soft-tissue cutting guides may be displayed as computer-graphical representations of the anatomical features and/or the soft-tissue cutting guides. The software may be configured to analyze the signals generated by the tracker in response to a sensed location and/or orientation of the trackable elements on the soft-tissue cutting guide and to display the relative orientation(s) of the anatomical features based on the tracked physical locations of the trackable elements attached to the soft-tissue cutting guide which may be tracked relative to a known location such as a trackable reference unit attached at a known point of the being's anatomy. In other words, the surgeon may place the patient-specific, trackable soft- tissue cutting guide on a patient while monitoring its location relative to known anatomical features of the being via a display which can show relative orientations of the computer- graphical representations of the soft-tissue cutting guide.

[0034] Upon cutting through the soft-tissue along the incision path, the surgeon may then use a custom-made bone cutting guide to provide the surgeon with slots that provide access for a cutting tool at preselecting cutting locations along the being's anatomy. After cutting sufficiently through the being's anatomy at the locations specified by the soft-tissue and bone-cutting guides, the anatomical feature is removed away from the recipient being. Subsequently, the transplanted anatomical feature, which may be harvested from the donor being in a similar manner as the anatomical feature is removed from the recipient, may be attached near the healthy portions of the recipient being's anatomy.

[0035] In an embodiment shown in FIGS. 1A-1H, there is a computer-assisted transplantation system 100 which may operate as the CAPE system described above, for example for use in a surgical method such as a transplantation procedure. The system 100 can include a donor sub-system 100-D and a recipient sub-system 100-R.

[0036] The donor sub-system may include a first reference unit 105-D having a first trackable element 101-D which may be integrated with, attached to, or detachably connected to a mount, such as a cranial reference mount 103. The first reference unit 105-D may be attached at a predetermined location on a donor being's anatomy 106-D, such as a predetermined anatomical feature 109-D, for example, a location of the donor's skull. The first reference unit 105-D may be attached via a mount 103 which may be a specially designed cranial reference mount. The donor sub-system 100-D may also include a second reference unit 105-D' having a second trackable element 101-D'. The second reference unit 105-D' may be a pointer tool, for example, a digitizer, which is used for tracing surfaces of the donor being's anatomy 106-D.

[0037] The donor sub-system 100-D may further include a first hard-tissue cutting guide

107-D having at least one of a trackable element 117-D. The hard-tissue cutting guide may include at least one attachment device (not visible) for coupling the first hard-tissue cutting guide 107-D to hard-tissue such as bone, and may also include at least one cut location indicator 1 19-D that identifies a location where on hard-tissue of the donor's anatomy 106-D is to be cut in order to, for example, remove/separate an anatomical fragment 11 1-D, such as a portion of the recipient's anatomy being donated to the recipient for attaching to the recipient in a transplantation procedure.

[0038] The donor sub-system 100-D may also include a first detector 113-D that may be configured to generate at least a first one of a signal 191 (as shown in FIG. 1H), such as electronic signals, in response to detecting at least the first and/or second trackable elements, wherein each of the electronic signals corresponds to a location of the first reference unit 105-D and/or the second reference unit 105-D' . The donor sub-system 100-D may further include a first computer 1 15-D that receives the signal 191. Thus, first detector 113-D may be configured for sensing locations of trackable elements, such as the first trackable element 101-D, the second trackable element 101-D', and/or the at least one of the trackable element 117-D. In an embodiment, as second reference unit 105-D' is moved along a surface of the donor being's anatomy, first detector 1 13-D may generate a signal representative of a location of the second reference unit 105-D' relative to a location of first reference unit 105-D (which remains at a static predetermined location on the donor's anatomy). A geometry of at least some portions of the donor's anatomy 106-D may, therefore, be determined from multiple signals generated by the detector detecting updated locations of the second reference unit 105-D' relative to a static location of the first reference unit 105-D. In an embodiment, the first detector 113-D detects a location of the at least one tracking element 1 17-D of the first hard-tissue cutting guide 107-D. For example, a fragment 111-D may be separated from the donor's anatomy 106-D by cutting through the donor being's hard-tissue at portions adjacent to the at least one cut location indicator 1 19-D. A computer-readable representation of the donor fragment 111-D' may be displayed on a display 1 15-D' portion of the first computer 1 15-D. The first detector 113-D, upon detecting a tracking element of the first cutting guide 107-D, generates a signal 191 which is accessed and interpreted by the computer for determining whether an orientation of the displayed computer-readable representation of the donor fragment 111-D requires being updated on the display 115-D'.

[0039] The recipient sub-system 100-R may include a third reference unit 105-R having a third trackable element 101-R which may be integrated with, attached to, or detachably connected to a mount, such as a cranial reference mount 103.. The third reference unit 105-R may be attached at a predetermined location on a recipient being's anatomy 106-R, such as a predetermined anatomical feature 109-R, for example, a location of the recipient's skull. The third reference unit 105-R may be attached via a mount 103 which may be a specially designed cranial reference mount. The recipient sub-system 100-R may also include a fourth reference unit 105-R' having a fourth trackable element 101-R'. The fourth reference unit 105-D' may be a pointer tool, for example, a digitizer, which is used for tracing surfaces of the recipient being's anatomy 106-R. In an embodiment, the second detector 113-R detects a location of the at least one tracking element 1 17-D of the second hard-tissue cutting guide 107-R. For example, a fragment 1 11-R may be separated from the recipient's anatomy 106-R by cutting through the recipient being's hard-tissue at portions adjacent to the at least one cut location indicator 119-R.

[0040] The recipient sub-system 100-R may further include a second hard-tissue cutting guide 107-R having at least one of a trackable element 1 17-R. The hard-tissue cutting guide may include at least one attachment device (not visible) for coupling the first hard-tissue cutting guide 107-R to hard-tissue such as bone, and may also include at least one cut location indicator 119-R that identifies a location where on hard-tissue of the recipient's anatomy 106-R is to be cut in order to, for example, remove/separate an anatomical fragment 11 1-R, such as diseased and/or damaged portion of the recipient's anatomy being removed from the recipient for replacing with a selected fragment 1 11-D of the donor in a transplantation procedure.

[0041] The recipient sub-system 100-R may also include a second detector 113-R that may be configured to generate at least a first one of a signal 191 (as shown in FIG. 1H), such as electronic signals, in response to detecting at least the third and/or fourth trackable elements, wherein each of the electronic signals corresponds to a location of the third reference unit 105-R and/or the fourth reference unit 105-R' . The recipient sub-system 100-R may further include a second computer 11 -R that receives the signal 191. Thus, second detector 113-R may be configured for sensing locations of trackable elements, such as the third trackable element 101- R, the fourth trackable element 101-R', and/or the at least one of the trackable element 117-R.In an embodiment, as fourth reference unit 105-R' is moved along a surface of the recipient being's anatomy, second detector 113-R may generate a signal representative of a location of the fourth reference unit 105-R' relative to a location of third reference unit 105-R (which remains at a static predetermined location on the recipient's anatomy). Meanwhile, fragment 1 11-D to which is attached the first cutting guide 107-D may be brought in proximity to second detector 1 13-R such that second detector 113-R is configured to generate at least one of a signal 191 as described above in response to detecting at least the trackable elements 1 17-D of the cutting guide 107-D. Additionally, first computer 1 15-D and second computer 1 15-R may receive/accept the computer-readable representation of the donor fragment 11 1-D' to recipient sub-system 100-R via a communications link such that it is displayed on display 1 15-R' and its orientation updated upon the sensor detecting updated location of the first cutting guide 107-D, for example as donor fragment 111-D is attached to the recipient's anatomy.. Also, a geometry of at least some portions of the recipient's anatomy 106-R may, therefore, be determined from multiple signals generated by the second detector 1 13-R detecting updated locations of the fourth reference unit 105-R' relative to the static location of the third reference unit 105-R. Accordingly, computer-readable representation of the recipient's anatomy 106-R' may also be displayed on a display 115-R' portion of the second computer 115-R. The second detector 1 13- D, upon detecting a tracking element 101-R of the second reference unit 105-R, generates a signal 1 1 which is accessed and interpreted by the computer for determining whether an orientation of the displayed computer-readable representation of the recipient anatomy 106-R' requires being updated on the display 115-R' in order to provide the user a visualization of the relative orientations of the donated fragment from the donor relative to the recipient's anatomy.

[0042] The at least one signal 191 may be communicated between the detectors and computers via a communications link, as indicated by the dashed double-headed arrow in FIGS 1A-1C, which may be data transmission wires and/or wireless transmissions either of which may be communicated through a network, such as a local area network (LAN) or wide area network (WAN), including communication over an intranet or over the internet, including TCP/IP data transfer. In an example, a communications link allows the first computer 115-D and the second computer 1 15-R to communicate with one another.

[0043] The first detector 1 13-D, the second detector 113-R, or both may be an optical tracker, a magnetic tracker or both an optical tracker and a magnetic tracker as generally shown in FIG. 1G as 113, and may be utilized in the system to perform a detecting function, as indicated by the double-headed dashed-dotted arrow in FIGS. IA-IC, for detecting locations of items. Optical trackers typically emit and capture light in the invisible (infrared) electromagnetic spectrum. Trackable fiducials used with these systems can include passive (i.e., reflective) or active (i.e., those that actively emit infrared light) markers. Using specific geometries known to the camera, the pose of a reference can be tracked through the field of view. An example system is the NDI Polaris available from Northern Digital, Inc. (Ontario, Canada). Magnetic trackers rely on a magnetic field generator and (typically) a passive coil architecture. The field generator creates a time -varying field, which induces a current in the passive sensor. This current is measured and, through a calibration procedure, used to identify up to a 6-dof pose of the sensor. An example system is the NDI Aurora available from Northern Digital, Inc. (Ontario, Canada).

[0044] One or more of the first trackable element 101-D, the second trackable element

101-D', the third trackable element 101-R, and the trackable elements 117-D may be an IR reflector or an IR emitter, as generally shown as 101 in FIG. ID, each of which may be detachably connected to an attachment surface such as a mount, including a cranial reference mount 2003, which may form part of a reference unit 103 as generally shown in FIG. IE. As an example, an IR reflector may be a detachably connected surface, such as a sphere. As an example, an IR emitter may be a light emitting diode configured to emit infrared light. [0045] The first and second computers may be selected from a desktop computer, a network computer, a mainframe, a server, or a laptop. The first and second computers may be configured to access at least one computer readable reconstruction of at least one object, such as a being's anatomy, or at least portions of the being's anatomy, for example, a computer-readable reconstruction of the donor fragment 1 11-D', and the computer-readable reconstruction of the recipient anatomy 106-R' . The computer-readable reconstructions may include three- dimensional (3D) views, such as those created by scanning an object via, for example, CT scan. The displays of the computers may be configured to represent the computer-readable reconstructions. The computers may include at least one memory to store data and instructions, and at least one processor configured to access the at least one memory and to execute instructions, such as the instructions of the method 400 described below for FIG. 4.

[0046] As shown in FIGS. 2A-2E, a surgical method of the embodiments may include a transplantation procedure by which a portion of a recipient's anatomy is replaced with a portion of a donor's anatomy. In FIG. 2A, during such a surgical procedure, a computer-readable (3- dimensional) reconstructions of a recipient's anatomy 106-R' are created. Virtual planned cutting planes 202, 206 (computer-readable segmentation planes) are superimposed on selected portions of the computer-readable reconstruction of the donor's anatomy 106-R' and intersect the virtual representations of the recipient's anatomy at locations to be cut on the actual recipient's anatomy. As shown in FIG. 2B, a surgical guide assembly (i.e., a hard-tissue cutting guide) can be designed to include cut location indicators based on a geometry of the interface 204', 208' between the planned-cut planes 202, 206 and portions of the computer-readable reconstruction of the recipient's anatomy. The surgeon then cuts through the recipient's hard-tissue (bone) guided by the cut location indicators to remove portions of the recipient's anatomy as shown in FIG. 2C. A fragment 11 1-D from the donor (shown in FIG. 2D) can then be attached to the recipient's anatomy 106-R as shown in FIG. 2E.

[0047] With respect to hard-tissue cutting guides of the embodiments, FIG. 2B illustrates an illustrative surgical guide assembly 210 coupled to a skull 200. The guide assembly 210 may include one or more attachment devices 220 (three are shown) for coupling the guide assembly 210 to the skull 200. As shown, the attachment devices 220 are configured to be coupled to the left zygomatic bone, the right zygomatic bone, and the nasal bone of the skull 200. In other embodiments, the attachment devices 220 may be configured to be coupled to other portions of the skull 200, such as the maxilla, mandible, or a combination thereof. In yet other embodiments, the attachment devices 220 may be configured to be coupled to bones other than the skull.

[0048] The attachment devices 220 may each include one or more openings 1522 (three are shown). A screw, bolt, or the like (not shown in FIG. 2B) may be inserted through each opening 222 and at least partially into the skull 200 to couple the guide assembly 210 to the skull 200. For example the screws may be from about 1 mm to about 3 mm surgical screws or from about 1.5 mm to about 2.5 mm surgical screws. Although shown as including openings 222 configured to receive screws, in other embodiments, the attachment devices 220 may include other mechanical connections to the skull 200, such as clamps or an adhesive.

[0049] The guide assembly 210 may also include one or more arms 230 (three are shown). A first end 232 of each arm 230 may be coupled to or integral with one of the attachment devices 220. In at least one embodiment, a second end 234 of each arm 230 may be coupled to or integral with a common point. For example, as shown, the second ends 234 of the arms 230 may be coupled to one another. As shown, the arms 230 may be curved or bent such that the second ends 234 are positioned farther out from the skull 200 than the first ends 232. In other embodiments, the arms 230 may be substantially straight.

[0050] The guide assembly 210 may further include one or more cut location indicators

240 (three are shown). As shown in FIG. 2B, the cut location indicators 240 may be positioned between the attachment devices 220 and the first ends 232 of the arms 230. As later shown, in other embodiments, the attachment devices 220 may be positioned between the first ends 232 of the arms 230 and the cut location indicators 240.

[0051] The cut location indicators 240 may identify locations on the skull 200 where the surgeon should make the cuts. In at least one embodiment, the cut location indicators 240 may include recesses 242 that extend partially through the guide assembly 210. In another embodiment, the cut location indicators 240 may be or include slots that extend all the way through the guide assembly 210 providing a path for a cutting device (e.g., a saw) to pass through to the skull 210.

[0052] A support structure 250 may be coupled to or integral with the guide assembly

210. For example, the support structure 250 may be coupled to or integral with the arms 230 (e.g., proximate to the second ends 234 of the arms 230). The support structure 250 may be or include one or more rods 252 (four are shown). The rods 252 may be coupled to or integral with one another at a common point 254 (e.g., proximate to where the rods 252 connect to the arms 230). As shown, the rods 252 may be substantially straight and in the same plane. In other embodiments, the rods 252 may be curved or bent.

[0053] An angle between two adjacent rods 252 may be from about 5° to about 175°, about 20° to about 160°, about 45° to about 135°, or about 60° to about 120°. As shown, the angles between adjacent rods 252 are about 90°. The rods 252 may each be substantially the same length, or two or more rods 252 may be different lengths, as measured from the common point 254.

[0054] An end of each rod 252 may include a connector 256. As shown, the connectors

256 may be male connectors that extend away from the ends of the rods 252 and/or away from the skull 250. In another embodiment, the connectors 256 may be female connectors (e.g., a threaded recess or opening). As discussed in greater detail below, a trackable feature may be coupled to each connector 256.

[0055] The attachment devices 220, the arms 230, the cut location indicators 240, the support structure 250, or a combination thereof may be made from a polymer, a resin, an epoxy, or a combination thereof. In addition, the attachment devices 220, the arms 230, the cut location indicators 240, the support structure 250, or a combination thereof may be integral with one another and manufactured by a 3D printer.

[0056] Prior to cutting through hard tissue with the assistance of a hard-tissue cutting guide, a surgical method of the embodiments, which may be a transplantation procedure, may require that the donor and or recipient beings' soft-tissue and/or vasculature be compromised, for example, by cutting through the soft-tissue and/or vasculature with the assistance of a soft-tissue cutting guide. The CAPE system described above can further be used for the design and /or manufacture of patient-specific soft-tissue cutting guides that have at least one surface that substantially conforms to the contours of a patient's anatomical characteristics. As shown in FIG. 3 A, the patient-specific soft-tissue cutting guide 301 described herein may be a surgical guide assembly having an attachment device (not visible) configured to be coupled to soft-tissue 302 of a being 304. A cut location indicator portion 103 of the soft-tissue cutting guide 301 identifies a location on the being where soft-tissue is to be cut. The cut location indicator portion 103 of the soft-tissue cutting guide may include a side-wall portion 305 of the cutting guide.

[0057] Generally, the soft-tissue cutting guide 301 can be designed to provide a reference outline that defines an incision path 306 along a first portion of the donor and/or recipient anatomy on which it is placed, while protecting adjacent portions of the anatomy that must not be incised. Accordingly, the dimensions of a soft-tissue cutting guide are determined on a per- patient basis, for example, based on CT scans of the patient which may be used for identifying cut locations.

[0058] Thus, the soft-tissue cutting guide may include a body portion that includes at least one contoured surface 107 that substantially corresponds to the contours of first portions of the being's anatomy, such as soft-tissue portions 302 of a being's anatomy. As such, the patient- specific soft tissue cutting guide 301 may be formed of a polymer, or at least the surface 107 may be formed of a polymer. In an example, the patient-specific soft tissue cutting guide 301 is made of plastic or metal using, for example, additive manufacturing. Additionally, at least a portion of the cutting guide 301 may be flexible enough to substantially conform to the soft- tissue portion of interest. The contoured surface 107 may be defined by, or terminate at, edges that correspond to the incision path. In an example, the edges may be the sidewalls 305 of the soft-tissue cutting guide 301. In an embodiment, the patient- specific, trackabie soft-tissue cutting guide may include at least one trackabie element (not shown) extending from the body of the soft-tissue cutting guide 301.

[0059] As known to one of ordinary skill in the surgical art, an incision path 306 (seen in

FIG. 3B) may be marked directly on a being (e.g., a surgical patient) using a writing instrument 308. In other words, a writing instrument 308, such as a marker, can be used for tracing around the soft tissue cutting guide and in one example, the edge portions of the soft-tissue cutting guide provide a reference for defining the surfaces on the anatomy to be marked by the writing instrument. Following tracing around the soft tissue cutting guide as shown in FIGS. 3A-3B, dissection 306' along the incision path 106 defined by the tracing may include all soft tissue including all pertinent or vascular structures as shown in FIG. 3C.

[0060] A method for fabricating a patient-specific, trackable soft-tissue cutting guide is depicted in flow chart 400 in FIG. 4. Such a method may be software instructions executed by a processor of a system for tracking donor and recipient surgical procedures simultaneously. In step 401 , a computer-readable representation of an anatomical feature is accessed. Such a computer-readable representation may comprise digital files created during a CT-scan of a being's anatomy. A user may be able to select a cut-plane on the computer-readable representation of the anatomical feature, for example, indicative of where the donor or recipient being's anatomical feature of interest is to be separated from the remainder of the being, and can then superimpose the cut-plane on the computer-readable representation of the anatomical feature at 403. A patient-specific, trackable soft tissue cutting guide may include a geometry defined by an intersection between the selected cutting plane and the computer-readable representation of the donor and/or recipient anatomy. Thus, the method continues at 405 with the step of generating a computer-readable representation of a soft-tissue guide. As described above, the soft-tissue cutting guide may comprise at least one surface that substantially corresponds to at least a portion of a geometry defined by an interface between the cut-plane and the computer-readable representation of the anatomical feature. Additionally, at 407 the computer-readable representation of the soft-tissue cutting guide may be accessed. For example, a processor of the system for tracking donor and recipient surgical procedures simultaneously may execute software instructions that include the accessing step in 407 and for controlling a device to form a soft-tissue cutting guide at 409. Accordingly, a patient-specific, trackable cutting guide may be designed and fabricated for one or each of the donor and the recipient in, for example, a transplantation procedure.

[0061] In an example, at least one trackable soft tissue cutting guide can be fabricated via an additive manufacturing modeling process, which can include, but is not limited to, stereolithography or 3D printing and the like. Indeed, the method by which a soft-tissue cutting guide is formed is not limited and may include controlling a device used in any additive or subtractive manufacturing process, or both. The device may be any manufacturing device that fabricates an object based on instructions, such as computer readable instructions, for example, instructions provided in digital data, including any device that utilizes additive or subtractive manufacturing technologies, such as those that fabricate an object from appropriately approved materials for medical use. Accordingly, the at least one device may be an additive manufacturing device, such as a 3D printer, or another kind of manufacturing device, including subtractive manufacturing device, such as a CNC machine. Examples of additive manufacturing technologies may include vat polymerization (e.g., PROJET® 6000, 7000, 8000 available from 3D Systems Corp., Rock Hill, SC), materials jetting (e.g., Objet 500 or Eden 250, each available from Stratasys, Ltd., Eden Prairie, MN), powder binding (e.g., PROJET® 460, 650 available from 3D Systems Corp., Rock Hill, SC), powder fusion (e.g., EBM® available from Arcam AB, Sweden), material extrusion (Fortus 250, 400, available from Stratasys, Ltd., Eden Prairie, MN), or any one denoted by the ASTM F42 committee on additive manufacturing. Accordingly, the CAPE system may include a device (not shown) for manufacturing components, such as patient- specific, trackable soft-tissue cutting guides and/or the trackable elements, and the device may be connected to at least one computer of the system via the communications link described above. The computer may be configured to execute instructions, such as software instructions, which may include generating a computer readable file that contains instructions for manufacturing the cutting guide and/or implant, for example a computer readable file that contains dimensions of a component, such as a patient-specific, trackable soft-tissue cutting guide based on the geometry of a planned cut path and contours of a being's anatomy which may be generated/stored as a computer-readable reconstruction of the being's anatomy. In an example, the computer-readable reconstruction of the being's anatomy may be a computer-readable file created from a CT-scan. In an example, the computer-readable reconstruction of the being's anatomy may be a 3D reconstruction of a patient's anatomy.

[0062] The design of a trackable cutting guide can implemented as part of the overall surgical procedure. For example, a least one planned cut plane may be selected and superimposed on a computer-readable representation of a donor and/or a recipient beings' anatomies. The planned cut plane(s) can be used to define a geometry of the soft tissue cutting guides to thereby provide a patient-specific soft tissue cutting guide customized to the contours of a being's anatomical features.

[0063] As described above, the patient-specific, trackable soft-tissue cutting guide may include at least one trackable element which may be detected by a detector. The detector may be an optical tracker, a magnetic tracker or both an optical tracker and a magnetic tracker. Optical trackers typically emit and capture light in the invisible (infrared) electromagnetic spectrum. Trackable fiducials (i.e., the trackable elements) used with these systems can include passive (i.e., reflective) or active (i.e., those that actively emit infrared light) markers. Using specific geometries known to the camera, the pose of a reference can be tracked through a field of view (as indicated by the dash-dotted lines). An example system is the NDI Polaris available from Northern Digital, Inc. (Ontario, Canada). Magnetic trackers rely on a magnetic field generator and (typically) a passive coil architecture. The field generator creates a time -varying field, which induces a current in the passive sensor. This current is measured and, through a calibration procedure, used to identify up to a 6-dof pose of the sensor. An example system is the NDI Aurora available from Northern Digital, Inc. (Ontario, Canada). Trackable elements enable dynamic intraoperative tracking of soft-tissue cutting guides with respect to the recipient's anatomical features, the location of which may be tracked via tracking (i.e., detecting) of a reference tracking element attached at a reference point of the recipient being's anatomy. The at least one trackable elements may be an IR reflector or an IR emitter, each of which may be detachably connected to a body of the soft-tissue cutting guide. As an example, an IR reflector may be a detachably connected surface, such as a sphere. As an example, an IR emitter may be a light emitting diode configured to emit infrared light.

[0064] Thus, a location of the soft-tissue cutting guide may be tracked by incorporating and/or attaching the trackable elements (e.g., optically reflective surfaces) on a surface of the soft-tissue cutting guide. An indication may be provided that the trackable soft-tissue cutting guide has been moved to/from an improper location from/to a proper location on the donor and/or recipient. For example, software instructions may be executed by a processor to induce a color change of a displayed computer readable representation of the soft-tissue cutting guide or its location when the actual soft-tissue cutting guide is moved to/from an improper location from/to a proper location. The proper placement of the soft-tissue cutting guide may be defined by combining positional information of the trackable soft tissue cutting guide with validated orthognathic measurements (i.e., real-time cephalometrics). [0065] While the present teachings have been illustrated with respect to one or more implementations, alterations and/or modifications may be made to the illustrated examples without departing from the spirit and scope of the appended claims. For example, it will be appreciated that while the process is described as a series of acts or events, the present teachings are not limited by the ordering of such acts or events. Some acts may occur in different orders and/or concurrently with other acts or events apart from those described herein. Also, not all process stages may be required to implement a methodology in accordance with one or more aspects or embodiments of the present teachings. It will be appreciated that structural components and/or processing stages may be added or existing structural components and/or processing stages may be removed or modified.

[0066] The terms "couple," "coupled," "connect," "connection," "connected," "in connection with," and "connecting" refer to "in direct connection with" or "in connection with via one or more intermediate elements or members." Further, one or more of the acts depicted herein may be carried out in one or more separate acts and/or phases. Furthermore, to the extent that the terms "including," "includes," "having," "has," "with," or variants thereof are used in either the detailed description and the claims, such terms are intended to be inclusive in a manner similar to the term "comprising." The term "at least one of is used to mean one or more of the listed items may be selected. Further, in the discussion and claims herein, the term "on" used with respect to two materials, one "on" the other, means at least some contact between the materials, while "over" means the materials are in proximity, but possibly with one or more additional intervening materials such that contact is possible but not required. Neither "on" nor "over" implies any directionality as used herein. [0067] Furthermore, as used herein, the phrase "one or more of, for example, A, B, and

C means any of the following: either A, B, or C alone; or combinations of two, such as A and B, B and C, and A and C; or combinations of three A, B and C.

[0068] Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

Claims

WHAT IS CLAIMED IS:

1. A patient-specific trackable soft tissue cutting guide for guiding a soft-tissue incision path, comprising:

a body, wherein the body comprises at least one surface that substantially corresponds to contours of at least one preselected soft-tissue portion of a being's anatomy; and

at least one trackable element extending from the body.

2. The cutting guide of claim 1, wherein the at least one surface comprises a polymer.

3. The cutting guide of claim 1 , wherein the at least one surface is substantially flexible to conform to the at least one preselected soft-tissue portion of the being's anatomy.

4. The cutting guide of claim I, wherein the at least one surface comprises a pre-determined geometry substantially conforms to the at least one preselected soft-tissue portion of the being's anatomy.

5. The cutting guide of claim 1, wherein the body comprises plastic or metal.

6. A method for fabricating a patient-specific trackable soft tissue cutting guide, comprising:

accessing a computer-readable representation of an anatomical feature; superimposing a cut-plane on the computer-readable representation of the anatomical feature, wherein an interface between the cut-plane and the computer-readable representation of the anatomical feature defines a geometry; and

generating a computer-readable representation of a cutting guide comprising at least one surface that substantially corresponds to at least a portion of the geometry.

7. The method of claim 6, further comprising controlling a device to form a soft-tissue cutting guide according to the computer-readable representation of the cutting-guide.

8. The method of claim 7, wherein the forming the cutting guide comprises an additive manufacturing process, a subtractive manufacturing process or both.

9. The method of claim 6, wherein the cutting guide comprises a body and at least one surface that substantially conforms to a portion of the anatomical feature and at least one edge portion that defines an incision path.

10. The method of claim 9, wherein the cutting guide further comprises trackable elements extending from the body.

11. The method of claim 10, wherein the trackable elements comprise an IR reflective surface.

12. The method of claim 6, wherein the computer-readable representation of an anatomical feature comprises CT-scan data.

13. A surgical method, comprising :

attaching a first reference unit comprising a first trackable element to a first anatomical feature of a being; and

placing a trackable soft-tissue cutting guide on a second anatomical feature of the being, wherein the trackable soft-tissue cutting guide comprises

a body and at least one surface that substantially conforms to a portion of the second anatomical feature of a being,

at least one edge portion that defines an incision path on the being, and at least one trackable element extending from the body.

14. The method of claim 13, further comprising tracking a location and/or orientation of the soft-tissue cutting guide relative to the reference unit.

15 The method of claim 14, further comprising marking the incision path on a surface of the being by tracing substantially along the at least one edge portion.

16. The method of claim 15, further comprising cutting a soft-tissue portion of the being's anatomical feature along the incision path.

18 The method of claim 13, wherein the at least one surface comprises a polymer.

19. The method of claim 13, wherein the at least one surface is substantially flexible to conform to the at least one preselected soft-tissue portion of the being's anatomy.

20. The method of claim 13, wherein the body comprises plastic or metal.