Craniomaxillofacial implant and method of designing the same

Abstract

To provide a method of designing a craniomaxillofacial implant that is a rigid plate of substantially uniform thickness, and a patient-specific craniomaxillofacial implant obtained by the method.SOLUTION: The method includes: positioning a surface element of a plate as a departure from a reference location within a base outline, the departure being represented by a fraction of the length of a normal path projected from the reference location to a predetermined soft tissue layer at a supported location within an anatomic region of interest, and the fraction being based upon a required patient-specific support at the supported location. The patient-specific craniomaxillofacial implant is formed into a warped rigid plate of substantially uniform thickness.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to medical instruments for bone surgery, in particular human bone implants, and more particularly to craniomaxillofacial, i.e. human skull and facial bone implants. The present invention further relates to methods, in particular computer-aided or computer-implemented, for designing and manufacturing such instruments. [Background technology]

[0002] Cranio-maxillofacial implants are used in reconstructive and cosmetic surgery. These two types of surgery have different objectives. Reconstructive surgery is performed to repair or replace missing (i.e., unhealthy) portions of the craniomaxillofacial bones, which may be caused by trauma or disease, whereas cosmetic surgery aims to improve the appearance of a patient's craniomaxillofacial features where there are no natural defects. However, a good patient appearance after surgery is important for both types of procedures, as they pertain to the patient's face, a body part that is important in terms of aesthetics and possibly quality of life. In fact, it is not uncommon for at least several cosmetic procedures to be performed after a reconstructive procedure, and for a patient to not be considered fully recovered until a significant restoration of facial appearance has been achieved. Because facial beauty is based on the symmetry of the opposite sides of the face, even a slight loss of aesthetic beauty is easily noticeable, but complete restoration is difficult to achieve.

[0003] One challenge with craniomaxillofacial transplants, which traditionally require multiple follow-up procedures, primarily lies in the relationship between the bone and the surrounding soft tissue layers. In the context of this technical field, particularly relevant soft tissue layers include fat, muscle, and / or skin. Atrophy and subsequent volume loss of this layer is particularly relevant in reconstructive surgery. Because it progresses gradually and unpredictably, the final volume loss tends to manifest over an uncertain period ranging from weeks to years.

[0004] Another challenge that further limits both types of craniomaxillofacial transplants is the potential trauma caused by the invasive nature of the procedure. The craniomaxillofacial region contains only a thin layer of bone and soft tissue that covers the body's delicate and vital organs, such as the brain, sinuses, and eyes, and the nerves that connect them. Ideally, craniomaxillofacial implants are small and thin; otherwise, large incisions are required for implantation, which further increases the likelihood of atrophy and volume loss that can later manifest and affect a larger portion of facial symmetry / aesthetics.

[0005] The above-mentioned obstacles to satisfactory post-operative facial aesthetics have been long-standing problems in the relevant arts.

[0006] Previous attempts to address this problem include U.S. Pat. No. 9,216,084 (B2) and U.S. Pat. No. 10,020,662 (B2) of a common patent family (collectively "Gordon et al.") that teach patient-specific craniomaxillofacial implants and methods for their design. The implants are particularly directed to cranial reconstructive procedures, more particularly, void filling. The implants further include a base portion having a first volume and a preoperatively designed curved augmentation portion having a second volume and positioned over at least a portion of the void to compensate for soft tissue loss. The outer surface of the craniomaxillofacial implant is asymmetrical relative to the contralateral bone of the skull. The implants' reliance on locally augmented volume for their primary function not only makes them bulky and invasive, but also limits their application to the cranium, a relatively large and thick portion of the craniomaxillofacial region least susceptible to this invasiveness. Furthermore, the design of the implant model by Gordon et al. is based on images or previously available data of the bone contralateral to the patient's cranial defect, which does not provide an accurate estimate of soft tissue loss.

[0007] Other notable previous attempts are U.S. Patent No. 9,895,211 (B2) ("Yaremchuk") and U.S. Patent No. 10,792,141 (B2) ("Brogan" et al.). Yaremchuk is directed to a craniofacial implant including first and second body portions secured by fastening elements and at least one registration flange for preventing movement of the implant relative to the mandible in at least one direction when the implant is positioned adjacent the mandible. Brogan et al., on the other hand, are directed to a flexible polymeric soft tissue provisional implant. Summary of the Invention [Problem to be solved by the invention]

[0008] The object of the present invention is to provide a novel craniomaxillofacial implant and a novel method for its design that can address common challenges in the craniomaxillofacial region, namely, loss of soft tissue layers and invasiveness, while also being applicable to multiple specific sites within this region. [Means for solving the problem]

[0009] Certain terms such as "post-operative images," "templates," and "clinical outcomes" are subject to their respective definitions provided in the detailed description section below.

[0010] In a first aspect, the invention is embodied in a method for designing a craniomaxillofacial implant that is a rigid plate having a substantially uniform thickness. The method includes positioning surface elements of the plate as deviations from a reference location within a base outline. The deviations are represented by a percentage of the length of a vertical path projected from the reference location onto a predetermined soft tissue layer at a support location within an anatomical region of interest. The percentage is based on the patient-specific support required at the support location.

[0011] The first aspect relates to the method required to realize the craniomaxillofacial implant according to the first aspect. In particular, the first aspect relates to the pre-operative configuration required for the warping of the plate of the implant according to the second aspect (summarized below) to provide the implant with the utility of (i) being set on and supported by at least the craniomaxillofacial bone and / or the soft tissue layer overlying the craniomaxillofacial bone, and (ii) compensating for or augmenting the elevation of the soft tissue layer by supporting the soft tissue layer in place of at least said craniomaxillofacial bone.

[0012] Furthermore, while prior art design methods are based on curves constructed from tangents determined from two-dimensional cross-sectional planes of images of a patient's craniomaxillofacial bones, the design method according to the first aspect of the present invention is based on surface elements positioned in terms of deviations from a reference position. This distinctive feature of the first aspect allows for deeper customization to address patient needs across a wide range of situations, which may cover from local compensation to cosmetic purposes. This feature also allows for the topology / warping of embodiments to be configured at sub-millimeter scales.

[0013] Preferably, the base outline is determined based on post-operative craniomaxillofacial images and pre-operative craniomaxillofacial images.

[0014] More preferably, the base outline includes surface constraints determined further based on the curvature of the soft tissue layer represented by the postoperative craniomaxillofacial image. And even more preferably, the required patient-specific support at the support location is further based on a volumetric difference between (i) the volume of the soft tissue layer determined from the postoperative craniomaxillofacial image and (ii) the volume of the soft tissue layer determined from the preoperative craniomaxillofacial image. The inventors have discovered that implementing the above references and bases, along with parameters determined therefrom, significantly improves the results of the method. The surface constraints thus determined minimize the area of ​​the base outline, thereby minimizing the invasiveness of the resulting implant. The required patient-specific support thus determined accurately represents the physical adjustments required for the desired surgical outcome.

[0015] In one embodiment, the postoperative craniomaxillofacial image is acquired by registering an anatomical reference region on the preoperative craniomaxillofacial image. This anatomical reference region is defined according to the craniomaxillofacial region with the densest soft tissue layer that is also located closest to the craniomaxillofacial bone to be operated on. The anatomical reference region defined in this manner will take into account the nearby craniomaxillofacial region with the densest soft tissue layer. Deformations in this region (e.g., atrophy, volume loss) are most likely to affect the accuracy of treatment and have the most significant effect on the accuracy of treatment.

[0016] Alternatively, the postoperative craniomaxillofacial image may be generated based on a mirrored contralateral craniomaxillofacial image, or if a mirrored image cannot be generated (e.g., in the case of a frontal bone defect), the postoperative craniomaxillofacial image may alternatively be generated based on a craniomaxillofacial template searchable in a library containing a plurality of such craniomaxillofacial templates. In the library alternative, the library is preferably searchable by comparing anatomical landmarks of the preoperative craniomaxillofacial image with anatomical landmarks of the craniomaxillofacial templates contained within the library. More preferably, the library is configured to update the craniomaxillofacial templates based on feedback information including clinical outcome data. In embodiments in which the library is configured to update the craniomaxillofacial templates, the updating of the craniomaxillofacial templates is most preferably performed by artificial intelligence.

[0017] It should be noted that embodiments using libraries are particularly useful when the implant being designed is for cosmetic surgery or reconstructive surgery where the contralateral craniomaxillofacial bone is unavailable due to damage, etc. The library provides a ready-to-use set of references for post-operative results that cannot be seen on the patient's own body (such as mirrored craniomaxillofacial images).

[0018] Optionally, the fraction varies across multiple reference locations within the base outline. Preferably, the fraction is further based on correlation factors determined by artificial intelligence trained on clinical outcome data. The artificial intelligence thus trained further compensates for any deformation of the soft tissue layers that may progress over time, thereby reducing the aesthetic impact of such progression and / or the risk of having to repeat surgery. Optionally, the length of the vertical path varies across multiple reference locations within the base outline. Also, optionally, the required patient-specific support varies across multiple reference locations within the anatomical region of interest.

[0019] Preferably, the required patient-specific support at the support location is further based on the geometry and final position of the soft tissue layers. The inventors envision the importance of considering geometry and position as separate parameters, which will be addressed later in the exemplary case of an orbital implant.

[0020] The embodiment according to the first aspect may further comprise any one of the steps of configuring the pores of the plate and configuring the mechanical reinforcement of the plate, or any combination of these steps, which in fact are directed to the design and configuration of optional or preferred components of the implant according to the second aspect summarized below.

[0021] Embodiments according to the first aspect can be implemented to design a wide range of craniomaxillofacial implants. Exemplary cases of implants designed with these embodiments include skull implants, frontal implants, maxillary implants, zygomatic implants, orbital implants, nasal implants, chin implants, and mandibular implants.

[0022] In a second aspect, the invention is embodied by a craniomaxillofacial implant, the implant being formed into a patient-specific, cambered, rigid plate having a substantially uniform thickness, the camber preoperatively configured to (i) rest on and be supported by at least the craniomaxillofacial bone and / or soft tissue layer overlying the craniomaxillofacial bone, and (ii) compensate for or augment the elevation of the soft tissue layer by supporting the soft tissue layer in place of at least the craniomaxillofacial bone.

[0023] According to a second aspect, the cambered rigid plate is one of the implant's distinctive features, reducing bulk and enhancing its adaptability. By relying on the camber rather than increasing its volume, the plate / implant remains thin and of a substantially uniform thickness throughout, thereby reducing the size of the required incision and potentially reducing intraoperative complications, such as pain, bleeding, and damage to nearby tissue. This second aspect is particularly advantageous when the patient's craniomaxillofacial skin is thin or inflexible, as in the case of elderly patients or patients suffering from other health conditions. This patient population would benefit from an implant according to this second aspect, as the invasive nature of prior art implants can lead to skin erosion.

[0024] This unique feature of the cambered rigid plate allows for even more customization, and the inventors also envision that the topology / camber of embodiments may be configurable on a sub-millimeter scale, which is enabled by the first aspect of the invention summarized above.

[0025] The curvature can also be preoperatively configured to adapt the implant to compensate for or augment the elevation of the soft tissue layer by supporting the soft tissue layer in place of at least the craniomaxillofacial bone, where the support is asymmetrical from the support provided by the contralateral portion of the craniomaxillofacial bone. The curvature of the implant according to this embodiment provides the contralateral asymmetry to compensate for the loss of the soft tissue layer and / or achieve the desired cosmetic result, as may be necessary in some circumstances.

[0026] Preferably, the substantially uniform thickness is within the range of 0.2 to 0.8 mm. The implant is preferably made of a biocompatible material, in particular titanium or its compounds / alloys, artificial materials, or silicone, and in particular a biocompatible ceramic such as hydroxyapatite.

[0027] The inventors envision that the soft tissue layer will most likely be one or more of muscle, fat, and skin, since other types of soft tissue layers that take up less space and do not layer over bone would have a much smaller impact on the aesthetics of the patient's face. However, embodiments in accordance with the present invention are fully applicable to other types of soft tissue layers.

[0028] In some situations, surgical planning may require that the implant rest on and be supported by at least both the craniomaxillofacial bone and the soft tissue layers (i.e., both the craniomaxillofacial bone and the soft tissue layers are disposed below the implant). As will be described below, the present invention allows for adaptation of embodiments to meet the requirements of such situations.

[0029] Preferably, the plate is also porous, further reducing bulk and overall weight. In some embodiments, the pores may even be configured in the form of a mesh. The loss of strength associated with pores can be addressed in embodiments that further include preoperatively configured mechanical reinforcement. This mechanical reinforcement can take many forms, including locally filling the pores and locally increasing the thickness of the plate. The locations of pore filling or plate thickening can be predetermined by a normal distribution that reinforces the overall strength of the plate and / or by selectively locating high-load areas of the plate.

[0030] Preferably, the implant further includes means for securing the implant on the craniomaxillofacial bone and / or for enhancing the stability of the implant on the craniomaxillofacial bone. An example of such means is a fastener protruding laterally from the plate boundary and having an opening for receiving a bone screw. Another notable example of such means is a fastener located within the plate boundary, which is an opening for a bone screw. Any form of such fastener and its surrounding plate region can also be adapted to flex depending on the topology of the patient's craniomaxillofacial bone and / or soft tissue layer, allowing the fastener to be attached to the bone and / or tissue with greater stability. Indeed, a key feature of this second embodiment, namely, the implant being formed into a cambered, rigid plate with a substantially uniform thickness, allows for fine customization of such fasteners to provide greater utility than simple screw holes.

[0031] Optionally, the curvature is pre-operatively configured to adapt the implant to support the soft tissue layer by receiving it in place of at least the craniomaxillofacial bone, or optionally, the curvature is pre-operatively configured to adapt the implant to support the soft tissue layer by elevating it above at least the craniomaxillofacial bone. These alternatives highlight the potential for embodiments in accordance with the present invention to be utilized in both reconstructive surgery (i.e., where the implant replaces a lost, deformed, or otherwise defective craniomaxillofacial bone) and cosmetic surgery (i.e., where the implant modifies support already provided by healthy craniomaxillofacial bone).

[0032] One embodiment may be an implant for reconstructing a missing craniomaxillofacial bone and a missing soft tissue layer overlying the missing craniomaxillofacial bone. Preferably, this embodiment (i) is positioned over and supported by at least the non-missing portion of the missing craniomaxillofacial bone and / or the missing portion of the missing soft tissue layer, and (ii) has a curvature preoperatively configured to adapt the implant to support the missing soft tissue layer in place of the missing portion of the missing craniomaxillofacial bone and the missing portion of the missing soft tissue layer. An exemplary case of the missing craniomaxillofacial bone is the skull, where the missing soft tissue layer includes the overlying temporalis muscle and fat. Another exemplary case of the missing craniomaxillofacial bone is the maxilla or zygomatic bone, where the missing soft tissue layer includes the overlying zygomaticus major muscle, zygomaticus minor muscle, and fat. Yet another exemplary case of such missing craniomaxillofacial bone is the orbit, where the missing soft tissue layers include the overlying orbicularis oculi, inferior rectus, inferior oblique, eyeball, and fat.

[0033] Furthermore, one embodiment may also be an implant for cosmetic surgery. Preferably, this embodiment (i) rests on and is supported by at least the craniomaxillofacial bone and / or soft tissue layer, and (ii) has a curvature configured preoperatively to adapt the implant to modify the apparent contour of the craniomaxillofacial bone by supporting the soft tissue layer in place of at least the craniomaxillofacial bone. An exemplary case of this cosmetic surgery is performed on the nasal bone or forehead. Another exemplary case of the cosmetic surgery is performed on the maxilla or cheekbone. Yet another exemplary case of the cosmetic surgery is performed on the mandible.

[0034] The principles of the present invention and its advantages will become apparent from the following description when considered in conjunction with the accompanying drawings, in which: [Brief explanation of the drawings]

[0035] [Figure 1] 1 is a schematic flow chart illustrating a method for designing a craniomaxillofacial implant, according to a preferred embodiment. [Figure 2] 1 is a schematic flow diagram illustrating steps for generating a post-operative craniomaxillofacial image according to a preferred embodiment. [Figure 3A] 4 is a schematic flow chart illustrating the steps of obtaining a template of a craniomaxillofacial image according to a first alternative of the preferred embodiment; [Figure 3B] 10 is a schematic flow diagram illustrating the steps of obtaining a template of a craniomaxillofacial image according to a second alternative of the preferred embodiment; [Figure 4] FIG. 1 is a front view (not to scale) showing a post-operative craniomaxillofacial image obtained by registering anatomical reference regions on a registered pre-operative craniomaxillofacial image, according to a preferred embodiment. [Figure 5A] FIG. 1 is a perspective view (not to scale) showing a pre-operative craniomaxillofacial image being segmented in accordance with a preferred embodiment. [Figure 5B] FIG. 1 is a perspective view (not to scale) showing a post-operative craniomaxillofacial image being segmented in accordance with a preferred embodiment. [Figure 6] 1 is a schematic flow diagram illustrating steps for determining a base outline according to a preferred embodiment; [Figure 7A] 1 is a diagram (not to scale) illustrating boundary and surface constraints determined as part of the step of determining a base outline, according to a preferred embodiment; [Figure 7B] 1 is a diagram (not to scale) illustrating an anatomical region of interest determined as part of the step of determining a base outline, according to a preferred embodiment. [Figure 8] 10 is a schematic flow diagram illustrating the steps for determining a vertical path from a base outline to a support location according to a preferred embodiment. [Figure 9A] FIG. 10 is a diagram (not to scale) illustrating the assignment of base outlines in a scenario where the supported soft tissue layers include muscle, fat, and skin, according to a preferred embodiment. [Figure 9B]FIG. 10 is a diagram (not to scale) illustrating the assignment of base outlines in a scenario where the supported soft tissue layer includes only fat and skin, according to a preferred embodiment. [Figure 10A] FIG. 1 is a diagram (not to scale) illustrating the allocation of support positions in a scenario where (1) the soft tissue layer to be supported includes muscle, fat, and skin, and (2) the edges of the implant are closed supportable edges, according to a preferred embodiment. [Figure 10B] FIG. 1 is a diagram (not to scale) illustrating the allocation of support positions in a scenario where (1) the soft tissue layer to be supported includes only fat and skin, and (2) the edges of the implant are closed supportable edges, according to a preferred embodiment. [Figure 10C] FIG. 1 is a diagram (not to scale) illustrating the allocation of support positions in a scenario where (1) the soft tissue layers to be supported include muscle, fat, and skin, and (2) the edges of the implant are open, supportable edges, according to a preferred embodiment. [Figure 10D] FIG. 1 is a diagram (not to scale) illustrating the allocation of support positions in a scenario where (1) the soft tissue layer to be supported includes only fat and skin, and (2) the edges of the implant are open, supportable edges, according to a preferred embodiment. [Figure 11] 1 is a schematic diagram (not to scale) showing the vertical path from the base outline to the support location as determined in the preferred embodiment. [Figure 12] 10 is a schematic flow diagram illustrating steps for determining volumetric differences of supported soft tissue layers according to a preferred embodiment; [Figure 13A] FIG. 1 is a front perspective view (not to scale) illustrating the difference between pre-operative and post-operative volumes of the same type of soft tissue layer as calculated in a preferred embodiment. [Figure 13B] FIG. 10 is a posterior cross-sectional view (not to scale) showing the difference between pre-operative and post-operative volumes of the same type of soft tissue layer as calculated in a preferred embodiment. [Figure 14] 10 is a schematic flow diagram illustrating steps for determining deviation from a reference position along a vertical path according to a preferred embodiment; [Figure 15A] FIG. 10 is a diagram (not to scale) showing deviation from a reference position along a perpendicular path relative to a first axis of a surface constraining curvature, as determined when the relevant bone is the skull, in accordance with a preferred embodiment. [Figure 15B] FIG. 10 is a diagram (not to scale) showing deviation from a reference position along a perpendicular path relative to the second axis of the surface constraining curvature, as determined when the relevant bone is the skull, in accordance with a preferred embodiment. [Figure 15C] 10 is a diagram (not to scale) illustrating the deviation from a reference position along a perpendicular path relative to the boundary of an implant under design, as determined when the bone involved is the skull, according to a preferred embodiment. [Figure 16] 10 is a schematic flow diagram illustrating steps for positioning a surface element according to a preferred embodiment; [Figure 17] 1A-1C are diagrams (not to scale) showing images of a cranial implant having its surface formed by positioning surface elements, according to a preferred embodiment. [Figure 18A] 1 is a diagram (not to scale) illustrating an exemplary embodiment in which the reference locations coincide with the craniomaxillofacial bones. [Figure 18B] 1 is a diagram (not to scale) illustrating an exemplary embodiment in which a reference location coincides with a soft tissue layer. [Figure 19] 1 is a schematic flow diagram illustrating steps for configuring pores and mechanical reinforcement according to a preferred embodiment. [Figure 20A] FIG. 1 shows a schematic image (not to scale) of an implant in which pores and mechanical reinforcements are configured according to a first alternative of a preferred embodiment. [Figure 20B] FIG. 1 shows a schematic image (not to scale) of an implant in which pores and mechanical reinforcements are configured according to a second alternative of the preferred embodiment. [Figure 21] 1 is a diagram (not to scale) illustrating the types of mechanical reinforcement modes according to a preferred embodiment. [Figure 22]FIG. 10 is a diagram (not to scale) illustrating the assignment of base outlines in a scenario where the only supporting soft tissue layers are fat and muscle, according to a preferred embodiment. [Figure 23A] FIG. 10 is a diagram (not to scale) showing the deviation from a reference position along a perpendicular path to the first axis of the surface constraining curvature, as determined when the associated bone is the orbit, in accordance with a preferred embodiment. [Figure 23B] FIG. 10 is a diagram (not to scale) showing deviation from a reference position along a perpendicular path to the second axis of the surface constraining curvature, as determined when the associated bone is the orbit, in accordance with a preferred embodiment. [Figure 23C] 10 is a diagram (not to scale) illustrating the deviation from a reference position along a perpendicular path relative to the boundary of the implant under design, as determined when the bone involved is the orbit, according to a preferred embodiment. FIG. [Figure 24] 1A-1C are images (not to scale) of an orbital implant having its surface formed by positioning surface elements, according to a preferred embodiment. [Figure 25A] FIG. 10 is a diagram (not to scale) showing deviation from a reference position along a perpendicular path relative to the first axis of the surface constrained curvature, as determined when the involved bones include the maxilla and zygomatic bone, in accordance with a preferred embodiment. [Figure 25B] FIG. 10 is a diagram (not to scale) showing deviation from a reference position along a perpendicular path relative to the second axis of the surface constrained curvature, as determined when the involved bones include the maxilla and zygomatic bone, in accordance with a preferred embodiment. [Figure 25C] FIG. 10 is a diagram (not to scale) showing deviations from a reference position along a perpendicular path relative to the boundary of an implant under design, as determined when the involved bones include the maxilla and zygomatic bone, in accordance with a preferred embodiment. [Figure 26] 1A-1C are images (not to scale) of maxillary and zygomatic implants whose surfaces have been formed by positioning surface elements, according to a preferred embodiment. [Figure 27A]10 is a diagram (not to scale) illustrating deviation from a reference position along a path perpendicular to the axis of the surface constrained curvature as determined when the relevant bone is the nasal bone, according to a preferred embodiment. [Figure 27B] 10 is a diagram (not to scale) illustrating the deviation from a reference position along a perpendicular path relative to the boundary of the implant under design, as determined when the bone involved is the nasal bone, according to a preferred embodiment. FIG. [Figure 28] 1A-1C are diagrams (not to scale) showing images of a nasal bone implant having its surface formed by positioning surface elements, according to a preferred embodiment. [Figure 29A] 1 is a diagram (not to scale) illustrating schematically the application of a cranial implant according to a preferred embodiment. [Figure 29B] 1 is a schematic diagram (not to scale) illustrating warping of a cranial implant, according to a preferred embodiment. [Figure 30A] 1 is a front perspective view (not to scale) showing a cranial implant according to a preferred embodiment. [Figure 30B] FIG. 1 is a rear perspective view (not to scale) showing a cranial implant according to a preferred embodiment. [Figure 31A] 1 is a schematic diagram (not to scale) illustrating application of an orbital implant according to a preferred embodiment. [Figure 31B] 1 is a schematic diagram (not to scale) illustrating warping of an orbital implant, according to a preferred embodiment. [Figure 32A] 1 is a front perspective view (not to scale) showing an orbital implant according to a preferred embodiment. [Figure 32B] FIG. 1 is a rear perspective view (not to scale) showing an orbital implant according to a preferred embodiment. [Figure 33A] 1 is a diagram (not to scale) illustrating the application of maxillary / zygomatic implants according to a preferred embodiment. [Figure 33B]1 is a schematic representation (not to scale) of the warping of a maxillary / zygomatic implant according to a preferred embodiment. [Figure 34A] FIG. 1 is a front perspective view (not to scale) showing a maxillary / zygomatic implant according to a preferred embodiment. [Figure 34B] FIG. 1 is a rear perspective view (not to scale) showing a maxillary / zygomatic implant according to a preferred embodiment. [Figure 35A] 1 is a diagram (not to scale) illustrating the application of a nasal bone implant according to a preferred embodiment. [Figure 35B] 1 is a schematic diagram (not to scale) illustrating the bowing of a nasal bone implant according to a preferred embodiment. [Figure 36A] FIG. 1 is a front perspective view (not to scale) showing a nasal bone implant according to a preferred embodiment. [Figure 36B] FIG. 1 is a rear perspective view (not to scale) showing a nasal bone implant according to a preferred embodiment. [Figure 37] 1 is a diagram (not to scale) illustrating the application of a mandibular implant according to a preferred embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0036] It should be understood that the following detailed description is directed to embodiments provided merely as examples to illustrate the concepts of the present invention. The present invention is not limited to the particular embodiments described, which may, of course, vary. It should also be understood that the terminology used herein is merely for the purpose of describing particular embodiments and is not intended to be limiting, since the scope of the present invention is limited only by the appended claims.

[0037] Although the detailed description of the present invention is divided into various sections, this is merely for the convenience of the reader, and disclosure found in any section may be combined with disclosure in another section.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0039] It should be noted that as used in this specification and the appended claims, the singular forms "a," "an," and "the" include the plural reference unless the context clearly dictates otherwise.

[0040] The term "about" used before numerical designations such as dimensions, times, and amounts, including ranges, indicates approximations that can vary by plus or minus 10%, 5%, or 1%, or any subrange or subvalue therebetween.

[0041] "Comprising" or "comprises" is intended to mean that compositions and methods include the recited elements, but do not exclude other elements. "Consisting essentially of," when used to define compositions and methods, is intended to mean excluding other elements that are essential to the combination for the stated purpose. Thus, an apparatus or method consisting essentially of the elements defined herein will not exclude other materials or steps that do not materially affect the basic and novel characteristics of the claimed invention. "Consisting of" is intended to mean excluding more than trace elements and substantial method steps of other components. Embodiments defined by each of these transitional phrases are within the scope of the present invention.

[0042] "Patient-specific configuration" refers to one or more configurations applicable to a specified embodiment feature that is specific to the needs of an individual patient. In particular, the term is intended to cover not only configurations readily apparent from bone and / or tissue images, but also configurations obtained by processing any information obtained from the patient, so long as the configuration can be applied to some of the embodiments. More particularly, notable examples of patient-specific configurations in this application include the dimensions, topology, and warpage of craniomaxillofacial implants according to embodiments.

[0043] "Soft tissue" or "soft tissue layer" refers to bodily tissue that has an adaptable cellular structure and contours, especially when subjected to pressure or deflection. Generally, soft tissue includes blood vessels, fat, tendons, ligaments, muscle, nerves, and skin, of which muscle, fat, and skin will be best referred to below in the detailed description. However, other types of soft tissue are not excluded from the scope of the present invention unless expressly stated.

[0044] A "post-operative image," as in "post-operative craniomaxillofacial image," refers to a medical image of a designated body part that visualizes that body part after the associated surgical procedure. A post-operative image in this sense is not an image taken after the actual surgery, but rather is determined pre-operatively by image processing (mirroring, registering, rendering, etc.) and / or from a library of images.

[0045] A "template" when used in reference to a bone or other body part refers to a pre-visualized image of the corresponding bone or body part that represents the ideal outcome of the surgery.

[0046] "Clinical outcome" refers to a medical condition resulting from a procedure or surgery over any period of time. This term is intended to include any observable condition, which may be quantitative or qualitative. Qualitative conditions include, but are not limited to, medical images. When a clinical outcome is a medical image, the image is taken of the patient after the actual surgery, and is therefore distinct from the "post-operative image" defined above.

[0047] How to design craniomaxillofacial implants

[0048] The first aspect of the present invention is directed to novel methods necessary to enable novel craniomaxillofacial implants according to the second aspect. It should be noted that the order of the steps and sub-elements thereof shown in the following drawings and referred to in the following description may be modified by those skilled in the art once they have fully understood this detailed description and the drawings.

[0049] 1 is a schematic flow diagram illustrating a method for designing a craniomaxillofacial implant according to a preferred embodiment. The craniomaxillofacial implant designed in this embodiment is a rigid plate of substantially uniform thickness. In this embodiment, method 100 begins with an image processing step 1000, which further includes a sub-element 1200 for acquiring a preoperative craniomaxillofacial image, a sub-element 1400 for generating a postoperative craniomaxillofacial image, and a sub-element 1600 for segmenting the craniomaxillofacial image. This embodiment of method 100 also includes a patient-specific support step 2000, which further includes a sub-element 2200 for determining a base outline, a sub-element 2400 for determining a vertical path from the base outline to a support location, and a sub-element 2600 for determining a volumetric difference of the soft tissue layer to be supported. In this embodiment, the base outline determination step 2200 processes information obtained by the craniomaxillofacial image segmentation 1600, the vertical path determination from the base outline to the support location step 2400 processes information obtained by the base outline determination 2200, and the volumetric difference determination of the supported soft tissue layer step 2600 processes information obtained by the craniomaxillofacial image segmentation 1600 and the vertical path determination from the base outline to the support location 2400. According to this embodiment, the information obtained by all sub-elements 2200, 2400, and 2600 of the patient-specific support step 2000 is further processed in step 3000 to determine deviations from the reference position along the vertical path. The preferred method 100 then proceeds to step 4000 of positioning surface elements and step 5000 of configuring pores and mechanical reinforcements.

[0050] 1 can be performed by performing any suitable medical imaging technique known in the art on the relevant craniomaxillofacial bones of the patient prior to surgery, including x-ray fluoroscopy, computed tomography (CT), and magnetic resonance imaging (MRI).

[0051] Figure 2 is a schematic flow chart illustrating steps for generating a postoperative craniomaxillofacial image according to a preferred embodiment. Here, step 1400 for generating a postoperative craniomaxillofacial image, previously shown in Figure 1, further includes the next sub-element, i.e., sub-element 1410 for acquiring a template of the craniomaxillofacial image. This acquired template is then processed in step 1420 for registering a preoperative craniomaxillofacial image with the template and step 1430 for defining an anatomical reference region on the template. This anatomical reference region is then extracted from the template in corresponding step 1440. The information obtained in the above sub-elements 1410, 1420, 1430, and 1440 is further processed in step 1450 for registering the anatomical reference region on the registered preoperative craniomaxillofacial image. A postoperative craniomaxillofacial image is then acquired in corresponding step 1460.

[0052] The step 1410 of obtaining a template of a craniomaxillofacial image shown in FIG. 2 may also be performed in a preferred alternative form shown in FIGS. 3A and 3B.

[0053] FIG. 3A is a schematic flow diagram illustrating a first alternative according to a preferred embodiment. In this first alternative, a craniomaxillofacial image template is obtained by mirroring the contralateral craniomaxillofacial image, i.e., the side not undergoing surgery. Accordingly, this first alternative for obtaining a craniomaxillofacial image template 1410A includes a subelement step 1412A of acquiring a contralateral craniomaxillofacial image, followed by a subelement step 1414A of mirroring the contralateral craniomaxillofacial image. Step 1410A can be performed by performing a suitable medical imaging technique known in the art on the patient's contralateral craniomaxillofacial bones before surgery. These known techniques include X-ray fluoroscopy, computed tomography (CT), and magnetic resonance imaging (MRI). Additionally, step 1410A may be performed simultaneously with step 1200 of acquiring a preoperative craniomaxillofacial image and this medical imaging technique. This first alternative form 1410A for obtaining a template of a craniomaxillofacial image is particularly used when the purpose of the associated surgery is to reconstruct a missing craniomaxillofacial bone, provided that the bone on the contralateral side of the patient is not affected by the defect.

[0054] FIG. 3B is a schematic flow chart illustrating a second alternative according to a preferred embodiment. In this second alternative, a plurality of templates are included in a library. The plurality of templates are not based on the patient's own craniomaxillofacial images, but are based on previous surgeries and / or are artificially generated. In this preferred embodiment, a template is selected from the plurality of templates based on a match between the patient's craniomaxillofacial anatomical structure and corresponding anatomical landmarks of the template. Notable examples of such anatomical landmarks include the zygomatic arch, mandibular condyle, nasal bone, and bony sutures. The patient's anatomical landmarks can be identified from the preoperative craniomaxillofacial image obtained in the corresponding step 1200 described above. Preferably, the library is a digital library with a plurality of templates preloaded into the library, and this preferred library is also searchable by comparing the anatomical landmarks of the preoperative craniomaxillofacial image with the anatomical landmarks of the craniomaxillofacial templates included in the library. Thus, this second alternative 1410B for obtaining a template of a craniomaxillofacial image includes a sub-element step 1412B for identifying anatomical landmarks on the preoperative craniomaxillofacial image, a sub-element step 1414B for matching these anatomical landmarks with a plurality of templates available in a library, and a sub-element step 1416B for selecting the best-matching template. More preferably, the library is configured to update the craniomaxillofacial template based on feedback information including clinical outcome data. Most preferably, this updating of the craniomaxillofacial template is performed by artificial intelligence, which may include any one or any combination of machine learning-based algorithms, statistical shape modeling (SSM), multi-objective shape optimization, and topology optimization. This second alternative 1410B for obtaining a template of a craniomaxillofacial image is particularly useful when the implant being designed is for cosmetic surgery or reconstructive surgery where the contralateral craniomaxillofacial bone is damaged or otherwise unavailable.The library provides a ready-to-use collection of references for post-operative results that cannot be seen on the patient's own body (such as mirrored craniomaxillofacial images).

[0055] The step 1420 of registering the pre-operative craniomaxillofacial image with the template, described above in connection with Figure 2, involves image data registration techniques known in the art, i.e., incorporating two sets of image data into one reference frame, including voxel-based registration, surface-based registration, and iterative closest point algorithms (ICP).

[0056] The anatomical reference region defined on the template in corresponding step 1430 and subsequently extracted from the template in corresponding step 1440, as described above in connection with FIG. 2, corresponds to the craniomaxillofacial region having the densest soft tissue layer that is also located closest to the craniomaxillofacial bone to be operated on. In an exemplary embodiment, if the bone to be operated on is the skull, the anatomical reference region corresponds to the zygomatic bone and / or temporal bone; if the bone to be operated on is the orbit, the anatomical reference region corresponds to the sphenoid bone and / or frontal process of the maxilla; if the bone to be operated on is the maxilla / zygomatic bone (i.e., a bone of the midface), the anatomical reference region corresponds to the maxilla and / or frontal bone; and if the bone to be operated on is the nasal bone, the nasal bone, maxilla, and / or frontal bone. After extraction, in corresponding step 1450, this anatomical reference region is registered on the preoperative craniomaxillofacial image previously aligned with the template in corresponding step 1420. The images registered in this manner then become the corresponding post-operative craniomaxillofacial images acquired in step 1460. An example of a post-operative craniomaxillofacial image acquired in this manner is shown in FIG.

[0057] 4 is a front view illustrating a postoperative craniomaxillofacial image obtained by registering an anatomical reference region on a registered preoperative craniomaxillofacial image, according to a preferred embodiment. Here, the postoperative craniomaxillofacial image 1452 is the product of registering an anatomical reference region 1456 (shaded) on a template-registered preoperative craniomaxillofacial image 1454 (unshaded). In this exemplary embodiment, the surgery involves reconstruction of the patient's damaged right skull, and therefore the anatomical reference region is determined to be the right zygomatic bone 1458. This right skull and right zygomatic bone 1458 are covered by the anatomical reference region 1456 (shaded).

[0058] Step 1600 of segmenting a craniomaxillofacial image, described above in connection with FIG. 1, involves image processing techniques utilized to recognize and distinguish certain soft tissue layers from a medical image. Known examples of such image processing techniques include region merging, adaptive thresholding, global thresholding, level setting, and K-means clustering. In a preferred embodiment, this segmentation is performed on both the preoperative craniomaxillofacial image acquired in corresponding step 1200 and the postoperative craniomaxillofacial image generated by corresponding step 1400. Examples of preoperative and postoperative craniomaxillofacial images segmented in this manner are shown in FIGS. 5A and 5B, respectively.

[0059] 5A is a perspective view showing a preoperative craniomaxillofacial image being segmented according to a preferred embodiment, while FIG. 5B is a perspective view showing a postoperative craniomaxillofacial image being segmented according to a preferred embodiment. In both of these exemplary embodiments, the surgery involves the reconstruction of a patient's damaged right skull.

[0060] In particular, Figure 5A shows a preoperative craniomaxillofacial image 1610 depicting, from innermost to outermost, a craniomaxillofacial bone 1612, a muscle layer 1614, which in this embodiment is the temporalis muscle, a fat layer 1616, and a skin layer 1618 after segmentation. Similarly, Figure 5B shows a postoperative craniomaxillofacial image 1620 depicting, from innermost to outermost, a craniomaxillofacial bone 1622, a muscle layer 1624, a fat layer 1626, and a skin layer 1628 after segmentation.

[0061] In an alternative embodiment, the surgery is on the patient's orbit and the muscle layer is the globe, orbicularis oculi, inferior rectus, and / or inferior oblique muscles, and in yet another alternative embodiment, the surgery is on the patient's maxilla / zygomatic bone and the muscle layer is the zygomaticus major and / or zygomaticus minor muscles.

[0062] 6 is a schematic flow diagram illustrating the steps of determining a base outline according to a preferred embodiment, where the step 2200 of determining a base outline previously shown in FIG. 1 further includes the following sub-elements: a sub-element 2220 of determining surface constraints, a sub-element 2240 of determining boundaries, and a sub-element 2260 of determining anatomical regions of interest, where the surface constraints and the anatomical regions of interest determined in the corresponding sub-element steps 2220 and 2260 are subsequently applied in a corresponding sub-element step 2280 to the boundaries determined in the corresponding sub-element step 2240 to generate a base outline. Furthermore, the determine surface constraints sub-element 2220 is implemented by obtaining 2222 the surface curvature represented by the post-operative craniomaxillofacial image and then generating 2224 the surface constraints based on the surface curvature; the determine boundary sub-element 2240 is implemented by locating 2242 the bony edges of the surgical target represented by the pre-operative craniomaxillofacial image and then generating 2244 the boundary based on the bony edges of the surgical target; and finally, the determine anatomical region of interest sub-element 2260 is implemented by comparing 2262 the soft tissue layers represented by the pre-operative and post-operative images and then locating 2264 the anatomical region of interest based on the area of ​​the soft tissue layer affected by the surgery. Details of these sub-element steps and their associated actions and products are shown in Figures 7A and 7B.

[0063] FIG. 7A illustrates the boundary and surface constraints determined as part of the base outline determination step, according to a preferred embodiment. Here, a preoperative craniomaxillofacial image 2300 represents the craniomaxillofacial bone 2310 of a patient with a damaged right skull, which is the surgical target bone in this embodiment. The damaged right skull is defined by the edge 2320 of the surgical bone. FIG. 7A further illustrates that a boundary 2330 is determined to surround the edge 2320 of the surgical bone, and a surface constraint 2340 is determined to represent the surface curvature within the region of the postoperative craniomaxillofacial image corresponding to this boundary 2330. The boundary 2330 and surface constraint 2340 described above are two of the three elements required for the preferred base outline determined in the corresponding subelement step 2200. FIG. 7B then illustrates the remaining element, namely, the anatomical region of interest.

[0064] Figure 7B illustrates an anatomical region of interest determined as part of the base outline determination step, according to a preferred embodiment. Here, a preoperative craniomaxillofacial image 2300 shows the craniomaxillofacial bones 2310 of the same patient as shown in Figure 7A above, from a right-side view. In Figure 7B, a surgical bone edge 2320 defines a surgical bone 2350, which is the injured right skull. Figure 7B further illustrates a region defined by a dashed line, which indicates a soft tissue layer portion of interest 2360 affected by surgery, determined by comparing the soft tissue layers shown in the preoperative and postoperative images. The region where the surgical bone 2350 intersects with the soft tissue layer portion of interest 2360 is determined to be an anatomical region of interest 2370. As will become more apparent later in this detailed description, this anatomical region of interest 2370 is then projected onto boundary 2330 (shown in FIG. 7A) modified by surface constraints 2340 (shown in FIG. 7A) to define the region within the implant from which the surface elements deviate, with reference positions assigned.

[0065] FIG. 8 is a schematic flow chart illustrating steps for determining a vertical path from the base outline to the support location, according to a preferred embodiment. Here, the step 2400 for determining a vertical path from the base outline to the support location, previously shown in FIG. 1, further includes the following subelements: a subelement 2410 for determining the soft tissue layer to be supported; a subelement 2430 for assigning the base outline adjacent to and below the bottom of the innermost layer of the soft tissue layer to be supported; a subelement 2450 for assigning a reference location to the base outline within the anatomical region of interest; a subelement 2470 for assigning a support location at the top of the outermost layer of the soft tissue layer to be supported within the anatomical region of interest; and finally a subelement 2490 for matching the reference location with the support location to form the vertical path. These subelement steps provide implants designed with a wide range of customized support schemes for the soft tissue layers, as shown in the following FIGS. 9A, 9B, 10A, 10B, 10C, 10D, and 11, all of which relate to an exemplary embodiment in which the patient's surgical target bone is a damaged right skull.

[0066] 9A and 9B illustrate possible results of a sub-element step 2410 that determines the soft tissue layers to be supported, and a sub-element step 2430 that assigns a base outline adjacent to and below the bottom of the innermost layer of the soft tissue layers to be supported.

[0067] 9A shows a schematic cross-sectional postoperative image of a right skull 2420A including, from innermost to outermost, a bone layer 2421, a muscle layer 2422, which in this embodiment is the temporalis muscle, a fat layer 2423, and a skin layer 2424. Here, the supported soft tissue layers are determined in the corresponding subelement steps to include all of the muscle layer 2422, the fat layer 2423, and the skin layer 2424. Accordingly, the base outline 2425A is assigned in the corresponding subelement step to be adjacent and below the bottom of the innermost layer of supported soft tissue, which in this case is the bottom of the muscle layer 2422. It can also be seen that if the implant being designed deviates from the base outline 2425A, the deviation will affect the support provided to all of the muscle layer 2422, the fat layer 2423, and the skin layer 2424.

[0068] 9B, on the other hand, shows a schematic cross-sectional postoperative image of a right skull 2420B including, from innermost to outermost, a bone layer 2421, a muscle layer 2422, which in this embodiment is the temporalis muscle, a fat layer 2423, and a skin layer 2424. Alternatively, the supported soft tissue layers here are determined in the corresponding subelement step to include only the fat layer 2423 and the skin layer 2424. Accordingly, the base outline 2425B is assigned in the corresponding subelement step to be adjacent and below the bottom of the innermost layer of supported soft tissue, which in this case is the bottom of the fat layer 2423. In this case, the muscle layer 2422 remains unsupported, and it can also be seen that if the implant being designed deviates from the base outline 2425B, the deviation will only affect the support provided to the fat layer 2423 and the skin layer 2424.

[0069] Figures 10A, 10B, 10C, and 10D illustrate possible results of subelement step 2450 of assigning a reference location to a base outline and subelement step 2470 of assigning a support location to the top of the outermost layer of soft tissue layers to be supported, performed within an anatomical region of interest. Note that this anatomical region of interest has been determined in accordance with the description associated with Figures 6, 7A, and 7B.

[0070] FIG. 10A shows a continuation of FIG. 9A of the first alternative. Here, a schematic cross-sectional postoperative image of a right skull 2460A includes, from innermost to outermost, a bone layer 2461, a muscle layer 2462, which in this embodiment is the temporalis muscle, a fat layer 2463, and a skin layer 2464. A base outline is assigned to the bottom of the muscle layer 2462, to which a reference location 2465A is assigned in a corresponding subelement step. Furthermore, a support location 2466A is assigned in a corresponding subelement step to the top of the outermost soft tissue layer to be supported, in this case the top of the skin layer 2464. The support location 2466A represents the expected geometry and final location of the soft tissue layers in the surgery, and thus the maximum support that can be obtained in this case, but is not necessarily the outline that the implant being designed will actually follow. The anatomical region of interest covers where the lines representing the reference location 2465A and the support location 2466A diverge. In this alternative, the support location 2466A is predetermined to converge with the reference location 2465A to form a closed supportable edge 2467A that is supported by the bone 2461.

[0071] FIG. 10B shows a continuation of FIG. 9B of the first alternative. Here, a schematic cross-sectional postoperative image of a right skull 2460B includes, from innermost to outermost, a bone layer 2461, a muscle layer 2462, which in this embodiment is the temporalis muscle, a fat layer 2463, and a skin layer 2464. A base outline is assigned to the bottom of the fat layer 2463, to which a reference position 2465B is assigned in a corresponding subelement step. Furthermore, a support position 2466B is assigned in a corresponding subelement step to the top of the outermost soft tissue layer to be supported, in this case the top of the skin layer 2464. The support position 2466B represents the expected geometry and final position of the soft tissue layers in the surgery, and thus the maximum support that can be obtained in this case, but is not necessarily the outline that the implant being designed will actually follow. The anatomical region of interest covers where the lines representing the reference position 2465B and the support position 2466B diverge. In this alternative, the support location 2466B is predetermined to converge with the reference location 2465B to form a closed supportable edge 2467B that is supported by the muscle layer 2462.

[0072] FIG. 10C shows a continuation of FIG. 9A of a second alternative. Here, a schematic cross-sectional postoperative image of a right skull 2460C includes, from innermost to outermost, a bone layer 2461, a muscle layer 2462, which in this embodiment is the temporalis muscle, a fat layer 2463, and a skin layer 2464. A base outline is assigned to the bottom of the muscle layer 2462, to which a reference location 2465C is assigned in a corresponding subelement step. Furthermore, a support location 2466C is assigned in a corresponding subelement step to the top of the outermost soft tissue layer to be supported, in this case the top of the skin layer 2464. The support location 2466C represents the expected geometry and final location of the soft tissue layers in surgery, and thus the maximum support that can be obtained in this case, but is not necessarily the outline that the implant being designed will actually follow. The anatomical region of interest covers where the lines representing the reference location 2465C and the support location 2466C diverge. In this alternative form, the support position 2466C remains branched from the reference position 2465C and is predetermined to form an open supportable edge 2467C that is not supported by any of the bone 2461, muscle layer 2462, fat layer 2463, and skin layer 2464.

[0073] FIG. 10D shows a continuation of FIG. 9B of a second alternative. Here, a schematic cross-sectional postoperative image of a right skull 2460D includes, from innermost to outermost, a bone layer 2461, a muscle layer 2462, which in this embodiment is the temporalis muscle, a fat layer 2463, and a skin layer 2464. A base outline is assigned to the bottom of the fat layer 2463, to which a reference location 2465D is assigned in a corresponding subelement step. Furthermore, a support location 2466D is assigned in a corresponding subelement step to the top of the outermost soft tissue layer to be supported, in this case the top of the skin layer 2464. The support location 2466D represents the expected geometry and final location of the soft tissue layers in the surgery, and thus the maximum support that can be obtained in this case, but is not necessarily the outline that the implant being designed will actually follow. The anatomical region of interest covers where the lines representing the reference location 2465D and the support location 2466D diverge. In this alternative form, the support position 2466D remains branched from the reference position 2465D and is predetermined to form an open supportable edge 2467D that is not supported by any of the bone 2461, muscle layer 2462, fat layer 2463, and skin layer 2464.

[0074] Next, FIG. 11 is a schematic diagram illustrating a vertical path from the base outline to the support locations, as determined in subelement step 2490 of matching reference locations with support locations to form a vertical path, as described above in connection with FIG. 8. In particular, FIG. 11 illustrates a preferred example of a simplified vertical path diagram 2500 for the case of an implant with an open supportable edge applied to an injured right skull (i.e., a continuation of FIG. 10C or FIG. 10D above). This vertical path diagram 2500 further includes lines representing a reference location 2510 and a support location 2530. Points on the reference location 2510 are reference nodes 2512 (circles), and similarly, points on the support location 2530 are support nodes 2532 (squares). A vertical path 2520 is a path projected perpendicularly from the reference node 2512 to the respective support node 2532, thereby filling the gap between the reference location 2510 and the support location 2530. It should be noted that one skilled in the art may adjust the density of nodes 2512 and 2532 at their respective locations 2510 and 2530 to achieve optimal results depending on the circumstances, and that the density shown in FIG. 11 is simplified for illustrative purposes and does not represent the density of nodes in an actual implementation of this method, in which a higher density of nodes may be preferred to design a smaller implant, or vice versa.

[0075] FIG. 12 is a schematic flow chart illustrating steps for determining volumetric differences of supported soft tissue layers according to a preferred embodiment. Here, step 2600 for determining volumetric differences of supported soft tissue layers, previously shown in FIG. 1, further includes the following subelements: subelement 2610 for grouping soft tissue layers of the same type from the segmented preoperative and postoperative craniomaxillofacial images; subelement 2630 for calculating the difference between the preoperative and postoperative volumes of the same type of soft tissue layer; subelement 2640 for applying the difference between the preoperative and postoperative volumes to the corresponding supported soft tissue layer; and subelement 2650 for summing the volumetric differences of all supported soft tissue layers. The volumetric differences determined by these subelement steps provide the method according to this preferred embodiment with quantifiable constraints that are applied to the total deviation from the reference position, thereby optimizing the support provided by the implant being designed. Details and products of some of the subelement steps shown in FIG. 12 are further illustrated in the following examples of FIGS. 13A and 13B.

[0076] Figure 13A is a front perspective view showing the difference between the preoperative and postoperative volumes of the same type of soft tissue layer, as calculated in a preferred embodiment. Figure 13B is a rear cross-sectional view showing the difference between the preoperative and postoperative volumes of the same type of soft tissue layer, as calculated in a preferred embodiment. Figures 13A and 13B are both different views showing the same craniomaxillofacial view with craniomaxillofacial bones 2710 of a patient with a damaged right skull 2712. Figures 13A and 13B further show the postoperative soft tissue layer 2713 and the preoperative soft tissue layer 2714, respectively, obtained in the corresponding segmentation step 1600 described above in Figure 1. The postoperative soft tissue layer 2713 and the preoperative soft tissue layer 2714 illustrated in Figures 13A and 13B are muscle layers (i.e., the temporalis muscle) as shown in Figures 5A and 5B. Visually overlaying the post-operative soft tissue layer 2713 and the pre-operative soft tissue layer 2714 in a common reference frame results in the soft tissue intersection 2715. In this case, the volumetric difference for the muscle layer calculated in the corresponding sub-element step 2630 is the volume of the post-operative soft tissue layer 2713 and the pre-operative soft tissue layer 2714 minus the volume of the soft tissue intersection 2715.

[0077] This volumetric difference is then applied to the corresponding supporting muscle layer in a corresponding sub-element step 2640. The same sub-element steps 2630 and 2640 are then repeated for the remaining supporting soft tissue layers depending on the surgical situation (e.g., in the case of the damaged right skull in Figures 13A and 13B, the remaining supporting soft tissue layers would be the fat and skin layers). The volumetric differences for all supporting soft tissue layers are then summed in a corresponding sub-element step 2650.

[0078] Next, FIG. 14 is a schematic flow chart illustrating steps for determining deviations from a reference position along a vertical path according to a preferred embodiment. Here, step 3000 for determining deviations from a reference position along a vertical path, previously shown in FIG. 1, further includes the following subelements: subelement 3200 for determining the elevation required to compensate for the volumetric difference between the preoperative and postoperative soft tissue layers to be supported; subelement 3400 for determining the fraction of the length of the vertical path projected from the reference position to the support position that causes the elevation; subelement 3500 for applying a correlation factor determined by artificial intelligence to the fraction; and subelement 3600 for obtaining a deviation vector represented by the fraction. Here, the total volume difference determined in the corresponding step 2600 is used as a constraint for the total deviation. Details of the subelement steps and products according to FIG. 14 are shown in the following FIGS. 15A, 15B, and 15C. FIGS. 15A, 15B, and 15C all relate to an exemplary embodiment in which the implant being designed is for reconstructive surgery to be performed on a patient's damaged right skull.

[0079] According to a preferred embodiment, Figures 15A, 15B, and 15C illustrate deviations from reference positions along the first axis, the second axis, and a perpendicular path relative to the boundary of the implant under design, respectively. Note that, first, while the first and second axes in Figures 15A and 15B are orthogonally oriented, this angular relationship can be adjusted by one skilled in the art to suit the surgical situation and is therefore not intended to limit the scope of this aspect of the invention; and, second, as with the earlier discussion related to Figure 11, the density of reference and support nodes shown in Figures 15A, 15B, and 15C is simplified for illustrative purposes only and therefore does not represent the density of nodes in an actual implementation of a preferred embodiment of this method. These considerations also apply fully to subsequent figures relating to alternative embodiments intended for different craniomaxillofacial bones.

[0080] 15A, 15B, and 15C show an implant base outline 3100 including the following elements: a boundary 3122, a surface constraint 3112, and an anatomical region of interest 3120. These three elements forming the base outline 3100 were determined in the corresponding step 2200 already shown and described in FIGS. 6, 7A, and 7B. According to FIGS. 15A, 15B, and 15C, the base outline 3100 is separated into two large zones: a baseline surface 3110 that does not contain deviations, and an anatomical region of interest 3120 that may contain deviations. The two large zones 3110 and 3120 are visually separated by a branching line 3121. For illustrative purposes, this branching line 3121 also serves as a reference for the different viewing angles seen from FIGS. 15A, 15B, and 15C.

[0081] 15A and 15B further show a plurality of reference locations 3126, preferably running along the surface constraint 3112, and a plurality of support locations 3127, which are shown overlapping the reference locations 3126 within the baseline surface 3110 and diverging from the reference locations 3126 within the anatomical region of interest 3120. FIGS. 15A and 15B also visualize a support boundary 3124 corresponding to the maximum possible lift provided by combining all support locations 3127. Between the two possible extremes indicated by the reference locations 3126 (i.e., 0% deviation from the baseline surface 3110) and the extreme limit indicated by the support locations 3127 (i.e., 100% deviation from the baseline surface 3110), are a plurality of deviation locations 3128 (i.e., a fractional deviation of x% from the baseline surface 3110, where x is represented by a fractional percentage between 0% and 100%). 11 above, FIGS. 15A and 15B show vertical paths projected from each of the reference nodes (0% deviation, O) along the reference location 3126 to each of the support nodes (100% deviation, D) along the support location 3127. Between each of the vertical paths, a deviation node (x% deviation, △) indicates the actual deviation from the baseline surface 3110 at that particular location. FIGS. 15A and 15B also show that the length of deviation varies across multiple of the reference locations 3126, and that the length of the vertical path varies across multiple of the reference locations 3126. It follows from this that, because the preferred embodiment according to FIGS. 15A and 15B accounts for different patient-specific support required across multiple reference locations 3126 within the anatomical region of interest 3120, the fractional percentage representing the x% deviation at the deviation location 3128 will also vary across multiple of the reference locations 3126. According to a preferred embodiment shown in Figure 14, in which step 3500 of applying a correlation factor determined by artificial intelligence to this fractional percentage is utilized, the fractional percentage representing a deviation of x% of the deviation location 3128 may vary within the same deviation location 3128. For example, application of the above correlation factor may result in x1, x2, and x3 shown in Figure 15B, which represent deviations at different deviation nodes (△) within the same deviation location 3128, becoming significantly different values.

[0082] 15C highlights a comparison between boundary 3122, support boundary 3124, and deviation boundary 3125 at the edge of anatomical region of interest 3120. In light of FIGS. 15A and 15B above, it is also emphasized that the deviation and / or fractional percentage of the vertical path may vary throughout anatomical region of interest 3120 depending on the patient-specific support required at a particular location, and therefore the deviation boundary 3125 may not necessarily represent the greatest deviation / fractional percentage within anatomical region of interest 3120.

[0083] FIG. 16 is a schematic flow diagram illustrating the steps for positioning surface elements according to a preferred embodiment. Here, the step 4000 for positioning surface elements previously shown in FIG. 1 further includes the following sub-elements: a sub-element 4200 for applying a deviation vector to a corresponding reference position in the base outline; a sub-element 4400 for positioning the surface element at the end of this vector; and finally, a sub-element 4600 for generating an implant surface including all surface elements. Examples of surface elements include pixels or voxels that are part of the final surface of the implant being designed. This deviation vector starts from the respective reference node and terminates at a deviation node located along its perpendicular path toward the respective support node. Where there is no deviation (e.g., a position within the baseline surface or a position within the anatomical region of interest but no deviation is assigned), the size of this deviation vector is zero, and therefore the surface element is positioned on the baseline surface. In this preferred embodiment, the first two sub-element steps 4200 and 4400 are repeated for all surface elements within the boundary until the implant surface is completely generated in the corresponding step 4600. The product and details of the above sub-element steps are shown in Figure 17 below.

[0084] FIG. 17 shows an image of a cranial implant, the surface of which is formed by positioning surface elements, according to a preferred embodiment. In particular, FIG. 17 shows a craniomaxillofacial image 4100 including the craniomaxillofacial bone 4110 of a patient with a damaged right skull 4112, to which an implant surface 4120 has been visually applied. FIG. 17 further shows possible ranges 4122 and 4124 within the anatomical region of interest, within which the implant surface 4120 may be positioned depending on deviations from the base outline and / or patient-specific support, which have been converted to percentages, as fully described in connection with the figures above. The minimum surface 4122 represents the case where no deviation from the base outline has been determined (i.e., 0% deviation throughout the implant surface), and therefore all surface elements remain on the base outline despite being an anatomical region of interest, while the maximum surface 4124 represents the case where all deviations within the anatomical region of interest coincide with the support boundary (i.e., 100% deviation throughout the anatomical region of interest). In this embodiment, after the step of positioning the surface elements of FIG. 16, all surface elements are positioned to form an optimum surface 4126 located between the minimum surface 4122 and the maximum surface 4124 .

[0085] It should be further noted that the reference location does not necessarily coincide with a craniomaxillofacial bone layer. While the above description is directed to an embodiment in which the reference location is located in a bone layer and the support and deviation locations represent an elevation from this bone layer to one of the overlying soft tissue layers, the method according to the first aspect does not necessarily have to be this way. Figures 18A and 18B below show an exemplary embodiment illustrating such a variation within the concept of the present invention.

[0086] FIG. 18A illustrates an exemplary embodiment in which the reference location coincides with a craniomaxillofacial bone. Alternatively, FIG. 18B illustrates another exemplary embodiment in which the reference location coincides with a soft tissue layer. Both FIG. 18A and FIG. 18B illustrate a craniomaxillofacial image 4100 of a patient including a craniomaxillofacial bone 4110 with an injured right skull 4112 and a soft tissue layer 4130, which in these embodiments is a skin layer. In FIG. 18A , a boundary 3122 with a reference location and respective reference nodes (0% deviation, ◯) coincides with the craniomaxillofacial bone 4110, a support boundary 3124 with a support location and respective support nodes (100% deviation, □) coincides with the skin layer 4130, and a deviation boundary 3125 with a deviation location and respective deviation node (x% deviation, △) represents an elevation from the reference location (i.e., the craniomaxillofacial bone 4110) toward the support location (i.e., the skin layer 3124). The direction of deviation shown in Figure 18A follows the embodiment described above in Figures 17 through 18. Figure 18B, on the other hand, shows the reverse direction of such deviation, where a boundary 3122 with a reference position and respective reference node (deviation 0%, circle) coincides with the skin layer 4130, a support boundary 3124 with a support position and respective support node (deviation 100%, square) coincides with the craniomaxillofacial bone 4110, and a deviation boundary 3125 with a deviation position and respective deviation node (deviation x%, triangle) represents a descent from the reference position (i.e., skin layer 4130) towards the support position (i.e., craniomaxillofacial bone 4110).

[0087] 19 is a schematic flow chart showing the steps of configuring pores and mechanical reinforcements according to a preferred embodiment, where the step 5000 of configuring pores and mechanical reinforcements previously shown in FIG. 1 further includes the next sub-element, namely, a sub-element 5100 of deciding whether to apply pores to the implant surface, where if yes, pores are applied to the implant surface in a corresponding step 5200, after which the method proceeds to a sub-element 5300 of deciding whether mechanical reinforcement is required, where if yes, the method proceeds to a sub-element 5400 of determining load distribution, which is the basis for a subsequent sub-element step 5500 of determining the location of reinforcement, and a sub-element of determining the type of reinforcement, where after the above-mentioned mechanical reinforcement elements have been determined in the corresponding sub-element steps 5400, 5500, and 5600, the method finally proceeds to a sub-element 5700 of applying this type to the reinforcement location. Alternatively, if either of the respective sub-element steps 5100 and 5300 returns a "no" answer, then the pore and mechanical reinforcement configuration step 5000 is terminated, and the implant being designed will not include pores and / or mechanical reinforcements without departing from the scope of the present invention. It is preferred by the inventors to include the issue of pores and mechanical reinforcements in one decision loop. This is because, in situations where it is necessary or desirable to apply pores to the implant surface, the pores will likely affect the mechanical strength of the final implant, so a decision regarding mechanical reinforcement can be made subsequently. It should also be noted that mechanical reinforcement may be applied selectively depending on the ancillary requirements of the surgery. For example, reinforcement may be applied uniformly to the implant surface, or non-uniformly based on specific conditions. In yet another example, reinforcement may be eliminated at certain locations on the implant surface to accommodate manual adjustments that may be made to that location of the implant during surgery. Details of the above sub-element steps and their products are shown in Figures 20A, 20B, and 21 below.

[0088] Optionally, Figure 20A is a schematic diagram showing an implant in which pores and mechanical reinforcements are configured according to a first alternative of a preferred embodiment. In this embodiment, a simplified implant 5800 includes an implant surface 5810 and a boundary 5820. Pores 5830 in the form of uniformly distributed hexagonal holes are determined in corresponding sub-element steps 5100 and 5200 and applied to the implant surface 5810. Furthermore, first alternative mechanical reinforcements 5840A in the form of uniformly distributed curved tracks that locally increase the thickness of the implant surface 5810 around the pores 5810 are determined in corresponding sub-element steps 5300, 5400, 5500, 5600, and 5700 and applied to the implant surface 5810.

[0089] Optionally, Figure 20B is a schematic diagram showing an implant in which pores and mechanical reinforcements are configured according to a second alternative preferred embodiment. In this embodiment, a simplified implant 5800 includes an implant surface 5810 and a boundary 5820. Pores 5830 in the form of uniformly distributed hexagonal holes are determined in corresponding sub-element steps 5100 and 5200 and applied to the implant surface 5810. Additionally, second alternative mechanical reinforcements 5840B in the form of two intersecting straight bars are determined in corresponding sub-element steps 5300, 5400, 5500, 5600, and 5700 and applied to the implant surface 5810, respectively, running symmetrically across the implant surface 5810, thickening the implant surface 510, and partially filling the pores 5830.

[0090] 21 illustrates a variety of mechanical reinforcement styles, according to preferred embodiments. These are examples of mechanical reinforcement styles that may be determined to be suitable for a surgical situation and / or implant in the corresponding sub-element step 5600. These examples, shown schematically by cross-sectional views of the implant surface, include thin tracks 5900A, which thicken the implant surface 5910A by supplementing thin reinforcements 5920A; wide tracks 5900B, which thicken the implant surface 5910B by supplementing wider reinforcements 5920B; bars 5900C, which attach bars 5920C to the implant surface 5910C, which may run over pores (not shown); and fillers 5900D, which do not thicken the implant surface 5910D but apply fillers 5920D to some of the pores to achieve the required mechanical reinforcement.

[0091] Alternative embodiments directed to other craniomaxillofacial bones

[0092] Next, the following Figures 22 through 28 illustrate several alternative embodiments related to the first aspect of the present invention (i.e., a method for designing a craniomaxillofacial implant). These alternative embodiments relate to applying this method to the design of craniomaxillofacial bones other than the skull, which has already been addressed by the previous figures and accompanying description. These figures also illustrate that the concepts of the present invention may be fully applied to other craniomaxillofacial bones without departing from the scope of the present invention. It should be noted that, for the sake of brevity, the following Figures 22 through 28 and their accompanying description only address significant differences between the design of implants for the skull and the respective other craniomaxillofacial bones. Details not mentioned in this method and its subelements should be considered to substantially follow the corresponding details of the above-described embodiment as applied to the design of cranial implants.

[0093] In particular, Figures 22-24 show the application of this embodiment to the design of orbital implants, Figures 25A-26 show the application of this embodiment to the design of maxillary / zygomatic (i.e., midface) implants, and Figures 27A-28 show the application of this embodiment to the design of nasal implants.

[0094] Orbital implant design

[0095] FIG. 22 illustrates the assignment of a base outline in a scenario where the supported soft tissue layers include only fat and muscle, according to an alternative embodiment. Specifically, FIG. 22 illustrates the application of the subelement step 2410 for determining the supported soft tissue layers seen in FIGS. 8, 9A, and 9B above, and the subelement step 2430 for assigning a base outline adjacent to and below the bottom of the innermost supported soft tissue layer, to the design of an orbital implant. Here, the cross-sectional postoperative image of the right orbit 2420C includes, from innermost to outermost, a bone layer 2421, a fat layer 2423, and then a muscle layer 2422. Unlike the skull, the skin layer is not relevant in this procedure, and the fat layer 2423 is closer to the bone layer 2421 than the muscle layer 2422, which in the case of the orbit is the eyeball. Because the supported soft tissue layer is determined in the corresponding subelement step to include both muscle layer 2422 and fat layer 2423, base outline 2425C is assigned in the corresponding subelement step to be adjacent and below the bottom of the innermost layer of supported soft tissue, which in this case is the bottom of fat layer 2423. It can also be seen that if the implant being designed deviates from base outline 2425C, the deviation will only affect the support provided to fat layer 2423. This is because, as previously mentioned, the skin layer is irrelevant and the muscle 2422 layer is the eyeball.

[0096] 23A, 23B, and 23C next show an implant base outline 3100 including the following elements: boundary 3122, surface constraints 3112, and anatomical region of interest 3120. These three elements forming the base outline 3100 were determined in the corresponding step 2200 already shown in and described according to FIGS. 6, 7A, and 7B. In particular, FIGS. 23A, 23B, and 23C show a scenario in which the sub-element step 3000 for determining deviations from a reference position along the vertical path seen in FIGS. 14, 15A, and 15B above is applied to the design of an orbital implant.

[0097] 23A, 23B, and 23C, the base outline 3100 is also separated into two large zones: a baseline surface 3110 that does not contain deviations, and an anatomical region of interest that may contain deviations 3120. The two large zones 3110 and 3120 are visually separated by a branching line 3121.

[0098] 23A and 23B further show a plurality of reference locations 3126, preferably running along the surface constraint 3112, and a plurality of support locations 3127, which are shown overlapping the reference locations 3126 within the baseline surface 3110 and diverging from the reference locations 3126 within the anatomical region of interest 3120. FIGS. 23A and 23B also visualize a support boundary 3124 corresponding to the maximum possible lift provided by combining all support locations 3127. Between the two possible extremes indicated by the reference locations 3126 (i.e., 0% deviation from the baseline surface 3110) and the extreme limit indicated by the support locations 3127 (i.e., 100% deviation from the baseline surface), there are a plurality of deviation locations 3128 (i.e., a fractional deviation of x% from the baseline surface 3110, where x is represented by a fractional percentage between 0% and 100%). 23A and 23B further show vertical paths projected from each of the reference nodes (0% deviation, O) along the reference location 3126 to each of the support nodes (100% deviation, D) along the support location 3127. Between each of the vertical paths, a deviation node (x% deviation, △) indicates the actual deviation from the baseline surface 3110 at that particular location. FIGS. 23A and 23B also show that the length of deviation varies across multiple of the reference locations 3126, and that the length of the vertical path varies across multiple of the reference locations 3126. It follows from this that, because the alternative embodiment according to FIGS. 23A and 23B accounts for different patient-specific support required across multiple reference locations 3126 within the anatomical region of interest 3120, the fractional percentage representing x% deviation at the deviation location 3128 will also vary across multiple of the reference locations 3126.

[0099] 23C highlights a comparison between boundary 3122, support boundary 3124, and deviation boundary 3125 at the edge of anatomical region of interest 3120. In light of FIGS. 23A and 23B above, it is also emphasized that the deviation and / or fractional percentage of the vertical path may vary throughout anatomical region of interest 3120 depending on the patient-specific support required at a particular location, and therefore the deviation boundary 3125 indicates a deviation / fractional percentage that may not necessarily be the greatest within anatomical region of interest 3120.

[0100] Figure 24 shows an image of an orbital implant having its surface formed by positioning surface elements, according to an alternative embodiment. In particular, Figure 24 shows a scenario in which the subelement step 4000 of positioning surface elements seen in Figures 16 and 17 above is applied to the design of an orbital implant.

[0101] FIG. 24 illustrates an image of an orbital implant, the surface of which is formed by positioning surface elements, according to an alternative embodiment. In particular, FIG. 24 illustrates a craniomaxillofacial image 4100 including the craniomaxillofacial bone 4110 of a patient with a damaged right orbit 4112 to which an implant surface 4120 has been visually applied. FIG. 24 further illustrates possible ranges 4122 and 4124 within the anatomical region of interest, within which the implant surface 4120 may be positioned depending on deviations from the base outline and / or patient-specific support, which have been converted to percentages, as fully described in connection with the figures above. The minimum surface 4122 represents the case where no deviation from the base outline has been determined (i.e., 0% deviation throughout the implant surface), and therefore all surface elements remain on the base outline despite being an anatomical region of interest, while the maximum surface 4124 represents the case where all deviations within the anatomical region of interest coincide with the support boundary (i.e., 100% deviation throughout the anatomical region of interest). In this embodiment, after the step of positioning the surface elements of FIG. 16 above, all surface elements have been positioned to form an optimum surface 4126 located between the minimum surface 4122 and the maximum surface 4124.

[0102] Maxillary / zygomatic (i.e. midface) implant design

[0103] 25A, 25B, and 25C show an implant base outline 3100 including the following elements: boundary 3122, surface constraints 3112, and anatomical region of interest 3120. These three elements forming the base outline 3100 were determined in the corresponding step 2200 already shown in and described according to FIGS. 6, 7A, and 7B. In particular, FIGS. 25A, 25B, and 25C show a scenario in which the subelement step 3000 for determining deviations from a reference position along the vertical path seen in FIGS. 14, 15A, 15B, and 15C above is applied to the design of a maxillary / zygomatic implant.

[0104] 25A, 25B, and 25C, the base outline 3100 is also separated into two large zones: a baseline surface 3110 that does not contain deviations, and an anatomical region of interest 3120 that may contain deviations. The two large zones 3110 and 3120 are visually separated by a branching line 3121. Contextually, the anatomical region of interest 3120 in this alternative embodiment is located in the middle of the four separated baseline surfaces 3110.

[0105] 25A and 25B further show a plurality of reference locations 3126, preferably running along the surface constraint 3112, and a plurality of support locations 3127, which are shown overlapping the reference locations 3126 within the baseline surface 3110 and diverging from the reference locations 3126 within the anatomical region of interest 3120. FIGS. 25A and 25B also visualize a support boundary 3124 corresponding to the maximum possible lift provided by combining all support locations 3127. Between the two possible extremes indicated by the reference locations 3126 (i.e., 0% deviation from the baseline surface 3110) and the extreme limit indicated by the support locations 3127 (i.e., 100% deviation from the baseline surface 3110), there are a plurality of deviation locations 3128 (i.e., a deviation of a fractional percentage of x% from the baseline surface 3110, where x is represented by a fractional percentage between 0% and 100%). 25A and 25B further show vertical paths projected from each of the reference nodes (0% deviation, O) along the reference location 3126 to each of the support nodes (100% deviation, D) along the support location 3127. Between each of the vertical paths, a deviation node (x% deviation, △) indicates the actual deviation from the baseline surface 3110 at that particular location. FIGS. 25A and 25B also show that the length of deviation varies across multiple of the reference locations 3126, and that the length of the vertical path varies across multiple of the reference locations 3126. It follows from this that, because the alternative embodiment according to FIGS. 25A and 25B accounts for different patient-specific support required across multiple reference locations 3126 within the anatomical region of interest 3120, the fractional percentage representing x% deviation at the deviation location 3128 will also vary across multiple of the reference locations 3126.

[0106] 25C highlights a comparison between boundary 3122, support boundary 3124, and deviation boundary 3125 at the edge of anatomical region of interest 3120. In light of FIGS. 25A and 25B above, it is also emphasized that the deviation and / or fractional percentage of the vertical path may vary throughout anatomical region of interest 3120 depending on the patient-specific support required at a particular location, and therefore the deviation boundary 3125 may not necessarily represent the greatest deviation / fractional percentage within anatomical region of interest 3120.

[0107] Figure 26 shows an image of a maxillary / zygomatic implant whose surface has been formed by positioning surface elements according to an alternative embodiment. In particular, Figure 26 shows a scenario in which the subelement step 4000 for positioning surface elements seen in Figures 16 and 17 above is applied to the design of a maxillary / zygomatic implant.

[0108] FIG. 26 illustrates an image of an implant whose surface has been formed by positioning surface elements according to an alternative embodiment. In particular, FIG. 26 illustrates a craniomaxillofacial image 4100 including a craniomaxillofacial bone 4110 of a patient with a damaged right maxilla / zygomatic bone 4112 to which an implant surface 4120 has been visually applied. FIG. 26 further illustrates possible ranges 4122 and 4124 within the anatomical region of interest, within which the implant surface 4120 may be positioned depending on deviations from the base outline and / or patient-specific support, which have been converted to percentages, as fully described in connection with the figures above. The minimum surface 4122 represents the case where no deviation from the base outline has been determined (i.e., 0% deviation throughout the implant surface), and therefore all surface elements remain on the base outline despite being an anatomical region of interest, while the maximum surface 4124 represents the case where all deviations within the anatomical region of interest coincide with the support boundary (i.e., 100% deviation throughout the anatomical region of interest). In this embodiment, after the step of positioning the surface elements of FIG. 16 above, all surface elements have been positioned to form an optimum surface 4126 located between the minimum surface 4122 and the maximum surface 4124.

[0109] Nose implant design

[0110] Figures 27A and 27B show an implant base outline 3100 including the following elements: boundary 3122, surface constraints 3112, and anatomical region of interest 3120. These three elements forming the base outline 3100 were determined in the corresponding step 2200 already shown in and described according to Figures 6, 7A, and 7B. In particular, Figures 27A and 27B show a scenario in which the sub-element step 3000 for determining deviations from a reference position along the vertical path seen in Figures 14, 15A, 15B, and 15C above is applied to the design of a nasal implant.

[0111] 27A, the base outline 3100 is also separated into two large zones: a baseline surface 3110 that does not contain deviations, and an anatomical region of interest that may contain deviations 3120. The two large zones 3110 and 3120 are visually separated by a branching line 3121.

[0112] Figure 27A further shows a number of reference locations 3126, preferably running along the surface constraint 3112, and a number of support locations 3127, which are shown overlapping the reference locations 3126 within the baseline surface 3110 and diverging from the reference locations 3126 within the anatomical region of interest 3120. Figure 27A also visualizes a support boundary 3124 corresponding to the maximum possible lift provided by combining all support locations 3127. Between the two possible extremes indicated by the reference locations 3126 (i.e., 0% deviation from the baseline surface 3110) and the extreme limit indicated by the support locations 3127 (i.e., 100% deviation from the baseline surface 3110), there are a number of deviation locations 3128 (i.e., a fractional deviation of x% from the baseline surface 3110, where x is represented by a fractional percentage between 0% and 100%). FIG. 27A further shows a vertical path projected from each of the reference nodes (0% deviation, O) along the reference location 3126 to each of the support nodes (100% deviation, D) along the support location 3127. Between each of the vertical paths, a deviation node (x% deviation, △) indicates the actual deviation from the baseline surface 3110 at that particular location. FIG. 27A also shows that the length of deviation varies across multiple of the reference locations 3126, and that the length of the vertical path varies across multiple of the reference locations 3126. It follows from this that, because the alternative embodiment according to FIG. 27A accounts for different patient-specific support required across multiple reference locations 3126 within the anatomical region of interest 3120, the fractional percentage representing the x% deviation at the deviation location 3128 will also vary across multiple of the reference locations 3126.

[0113] 27B highlights a comparison between boundary 3122, support boundary 3124, and deviation boundary 3125 within anatomical region of interest 3120. In light of FIG. 27B above, it is also emphasized that the deviation and / or fractional percentage of the vertical path may vary throughout anatomical region of interest 3120 depending on the patient-specific support required at a particular location, and therefore the deviation boundary 3125 indicates a deviation / fractional percentage that may not necessarily be the greatest within anatomical region of interest 3120.

[0114] Figure 28 shows an image of a nasal implant whose surface has been formed by positioning surface elements, according to an alternative embodiment. In particular, Figure 28 shows a scenario in which the subelement step 4000 of positioning surface elements seen in Figures 16 and 17 above is applied to the design of a nasal implant.

[0115] FIG. 28 shows an image of a nasal implant, the surface of which is formed by positioning surface elements, according to an alternative embodiment. In particular, FIG. 28 shows a craniomaxillofacial image 4100 including a craniomaxillofacial bone 4110 of a patient having a nasal bone 4112 (in the context of this description, this nasal bone includes nasal cartilage) on which cosmetic surgery will be performed by applying a nasal implant having a correspondingly visualized implant surface 4120. FIG. 28 further shows possible ranges 4122 and 4124 within the anatomical region of interest, within which the implant surface 4120 can be positioned depending on deviations from the base outline and / or patient-specific support, which have been converted into percentages, as fully described in connection with the above figures. The minimum surface 4122 represents the case where no deviation from the base outline has been determined (i.e., 0% deviation throughout the implant surface), and therefore all surface elements remain on the base outline despite being an anatomical region of interest, while the maximum surface 4124 represents the case where all deviations within the anatomical region of interest coincide with the support boundary (i.e., 100% deviation throughout the anatomical region of interest). In this embodiment, after the step of positioning the surface elements of FIG. 16 above, all surface elements have been positioned to form an optimum surface 4126 located between the minimum surface 4122 and the maximum surface 4124.

[0116] Cranio-maxillofacial implants

[0117] A second aspect of the present invention is directed to a novel craniomaxillofacial implant enabled by the design method according to the first aspect. It should be noted that the sub-elements of the implant shown in the subsequent drawings and referred to in the following description may be modified by one skilled in the art upon a full understanding of this detailed description and drawings.

[0118] Cranial implants

[0119] FIG. 29A is a schematic diagram illustrating application of a cranial implant according to a preferred embodiment. In this embodiment, the cranial maxillofacial implant is in the form of a cranial implant 200 that is applied to a patient's cranial maxillofacial bone 10, specifically the injured right skull 12. This cranial implant 200 is formed into a cambered, rigid plate having a substantially uniform thickness, according to the design enabled by the first aspect. The camber 220 is preoperatively configured to adapt the cranial implant 200 to rest on and be supported by at least the cranial maxillofacial bone (i.e., the right skull 12) and to compensate for or augment the elevation of the soft tissue layer (not shown) by supporting the soft tissue layer in place of at least the cranial maxillofacial bone. An example scenario in which the camber 220 is preoperatively configured to adapt the cranial implant 200 to rest on and be supported by the soft tissue layer above the cranial maxillofacial bone is shown in FIG. 10B above, in which the resulting implant is supported by a muscle layer. The following Figure 29B further illustrates that the camber 220 is non-uniformly distributed on the implant 200 as indicated by the topological mapping 222. According to both Figures 29A and 29B, the support provided to the soft tissue layer by the camber 220 is asymmetrical from the support provided by the contralateral portion 11 of the craniomaxillofacial bone 10.

[0120] FIG. 30A is a front perspective view of a cranial implant according to a preferred embodiment. In this embodiment, the cranial implant 200 is constructed from a titanium alloy and formed into a rigid plate having a substantially uniform thickness within the range of 0.2-0.8 mm. This thickness range is also an important novel feature enabled by the first aspect. Similar to FIGS. 29A and 29B above, the cranial implant 200 includes a camber 220 that is non-uniformly distributed across the implant 200. FIG. 30A also shows the cranial implant 200 as further including pores 230 in the form of non-uniformly distributed circular holes, each connected by a plurality of thin struts, and preferably four means 240 for anchoring the cranial implant 200 on the craniomaxillofacial bone. Note also that the pore configuration can be configured to meet specific surgical needs, such as required strength and breathability. In this embodiment, each of the anchoring means 240 is in the form of a fin that projects laterally outward from the boundary 210 of the cranial implant 200. The fixing means 240 features threaded holes 242 for the insertion of screws (not shown). According to the rear perspective view of Figure 30B, the cranial implant 200 further comprises mechanical reinforcements 250 in the form of non-uniformly distributed curved tracks that locally increase the thickness of the implant surface around the pores 230.

[0121] Orbital implants

[0122] FIG. 31A is a schematic illustration of the application of an orbital implant according to a preferred embodiment. In this embodiment, the craniomaxillofacial implant is in the form of an orbital implant 300 applied to a patient's craniomaxillofacial bone 10, specifically the injured right orbit 13. The orbital implant 300 is formed into a cambered, rigid plate having a substantially uniform thickness, in accordance with the design enabled by the first aspect. The camber 320 is preoperatively configured to accommodate the orbital implant 300 to rest on and be supported by at least the craniomaxillofacial bone (i.e., the right orbit 13) and compensate for or augment the elevation of the soft tissue layer (not shown) by supporting the soft tissue layer in place of at least the craniomaxillofacial bone. The following FIG. 31B further illustrates that the camber 320 is non-uniformly distributed on the implant 300, as indicated by topology mapping 322. The support provided to the soft tissue layer by the camber 320 is asymmetrical with respect to the support provided by the contralateral portion of the craniomaxillofacial bone.

[0123] FIG. 32A is a front perspective view of a cranial implant according to a preferred embodiment. In this embodiment, the orbital implant 300 is constructed from a titanium alloy and formed into a rigid plate having a substantially uniform thickness within the range of 0.2-0.8 mm. This thickness range, also an important novel feature enabled by the first aspect, is particularly advantageous when the implant is intended for the orbit, which is more susceptible to invasive procedures than the cranium. Similar to FIGS. 31A and 31B above, the orbital implant 300 includes a non-uniformly distributed camber 320 on the implant 300. FIG. 32A also shows the orbital implant 300 as further including non-uniformly distributed pores 330 in the form of hexagonal holes and means 340 for preferably securing the orbital implant 300 on the craniomaxillofacial bone. In this embodiment, the securing means 340 are located within the boundary 310 of the orbital implant 300. Each of the securing means 340 features a screw hole 342 for inserting a screw (not shown). In this embodiment, where the nature of the orbital bone requires additional stability of the implant 300, the fixation means 340 are also adapted to bend to provide an additional surface adjacent the inferior rim of the orbit, thereby increasing stability, as already shown in Figures 31A and 31B. For the same reason, this embodiment also includes ridges 360 adapted to further increase the stability of the orbital implant 300 when set on and supported by the craniomaxillofacial bone. According to the rear perspective view of Figure 32B, the orbital implant 300 includes two such ridges 360, as well as mechanical reinforcements 350 in the form of non-uniformly distributed curved tracks that locally increase the thickness of the implant surface around the pore 330.

[0124] Maxillary / zygomatic (i.e. midface) implants

[0125] FIG. 33A is a schematic illustration of the application of a maxillary / zygomatic implant according to a preferred embodiment. In this embodiment, the craniomaxillofacial implant is in the form of a maxillary / zygomatic implant 400 that is applied to a patient's craniomaxillofacial bone 10, specifically the injured right maxilla / zygomatic bone 14. The maxillary / zygomatic implant 400 is formed into a cambered, rigid plate having a substantially uniform thickness, in accordance with the design enabled by the first aspect. The camber 420 is preoperatively configured to accommodate the maxillary / zygomatic implant 400 to be set on and supported by at least the craniomaxillofacial bone (i.e., the right maxilla / zygomatic bone 14) and to compensate for or augment the elevation of the soft tissue layer (not shown) by supporting the soft tissue layer in place of at least the craniomaxillofacial bone. The following FIG. 33B further illustrates that the camber 420 is non-uniformly distributed on the implant 400, as indicated by a topological mapping 422. The support provided to the soft tissue layer by the camber 420 is asymmetrical from the support provided by the contralateral portion of the craniomaxillofacial bone.

[0126] FIG. 34A is a front perspective view of a maxillary / zygomatic implant according to a preferred embodiment. In this embodiment, the maxillary / zygomatic implant 400 is constructed of a titanium alloy and formed into a rigid plate having a substantially uniform thickness within the range of 0.2-0.8 mm. This thickness range is also an important novel feature enabled by the first aspect. Similar to FIGS. 33A and 33B above, the maxillary / zygomatic implant 400 includes a non-uniformly distributed camber 420 on the implant 400. FIG. 34A also shows the maxillary / zygomatic implant 400 as further including non-uniformly distributed pores 430 in the form of hexagonal holes and preferably three means 440 for anchoring the maxillary / zygomatic implant 400 on the craniomaxillofacial bone. In this embodiment, each of the anchoring means 440 is in the form of a fin projecting laterally outward from the boundary 410 of the maxillary / zygomatic implant 400. This fixing means 440 features two screw holes 442 for the insertion of screws (not shown), respectively. According to the posterior perspective view of FIG. 34B, the maxillary / zygomatic implant 400 further comprises mechanical reinforcements 450 in the form of non-uniformly distributed curved tracks that locally increase the thickness of the implant surface around the pore space 430.

[0127] Nose implant

[0128] FIG. 35A is a schematic diagram illustrating the application of a nasal implant according to a preferred embodiment. In this embodiment, the craniomaxillofacial implant is in the form of a nasal implant 500 that is applied to a patient's craniomaxillofacial bone 10, specifically the nasal bone 15 (in the context of this description, the nasal bone includes the nasal cartilage) where cosmetic surgery will be performed. The nasal implant 500 is formed into a cambered, rigid plate having a substantially uniform thickness, according to a design enabled by the first aspect. The camber 520 is preoperatively configured to accommodate the nasal implant 500 to be set on and supported by at least the craniomaxillofacial bone (i.e., the nasal bone 15) and to compensate for or augment the elevation of the soft tissue layer (not shown) by supporting the soft tissue layer in place of at least the craniomaxillofacial bone. The following FIG. 35B further illustrates that the camber 520 is non-uniformly distributed on the implant 500, as indicated by a topological mapping 322.

[0129] FIG. 36A is a front perspective view of a nasal implant according to a preferred embodiment. In this embodiment, the nasal implant 500 is constructed of silicone and formed into a rigid plate having a substantially uniform thickness within the range of 0.2-0.8 mm. This thickness range, also an important novel feature enabled by the first aspect, is particularly advantageous when the implant is intended for the nasal bone, which is more susceptible to invasive procedures than the skull. Similar to FIGS. 35A and 35B above, the nasal implant 500 includes a camber 520 that is non-uniformly distributed over the implant 500. FIG. 36A also shows the nasal implant 500 as further including non-uniformly distributed pores 530 in the form of hexagonal holes, and preferably two first fixation means 540A and two second fixation means 540B that together secure the nasal implant 500 on the craniomaxillofacial bone. In this embodiment, each of the first fastening means 540A is in the form of a fin protruding laterally outward from the boundary 510 of the nasal implant 500, and each of the first fastening means 540A features two screw holes 542A for inserting a screw (not shown). Additionally, each of the second fastening means 540B is in the form of a fin protruding laterally outward from the boundary 510 of the nasal implant 500, and each of the second fastening means 540B features one screw hole 542B for inserting a screw (not shown). According to the rear perspective view of FIG. 36B , the nasal implant 500 further includes mechanical reinforcements 550 in the form of non-uniformly distributed curved tracks that locally increase the thickness of the implant surface around the pores 530.

[0130] Mandibular implant

[0131] 37 is a schematic illustration of the application of a mandibular implant according to a preferred embodiment. In this embodiment, the craniomaxillofacial implant is in the form of a mandibular implant 600 that is applied to a patient's lower craniomaxillofacial bone 20, specifically the injured left mandible 22. The mandibular implant 600 is formed into a cambered, rigid plate having a substantially uniform thickness, in accordance with the design enabled by the first aspect. The camber 620 is preoperatively configured to adapt the mandibular implant 600 to rest on and be supported by at least the craniomaxillofacial bone (i.e., the left mandible 22) and to compensate for or augment the elevation of the soft tissue layer (not shown) by supporting the soft tissue layer in place of at least the craniomaxillofacial bone. The support provided to the soft tissue layer by the camber 620 is asymmetrical with respect to the support provided by the contralateral portion of the craniomaxillofacial bone.

[0132] Details of the mandibular implant remainder, as well as other possible alternative embodiments for application to other types of craniomaxillofacial bones, will be understood by those skilled in the art with knowledge of the above exemplary embodiments and are omitted for the sake of brevity, without limiting the concept of the present invention.

Claims

1. 1. A patient-specific craniomaxillofacial implant formed in a cambered rigid plate having a substantially uniform thickness, said camber comprising: being placed on and supported by at least the craniomaxillofacial bone and / or a soft tissue layer overlying the craniomaxillofacial bone; preoperatively configured to adapt the implant to compensate for or augment elevation of the soft tissue layer by supporting the soft tissue layer in place of at least the craniomaxillofacial bone; Patient-specific craniomaxillofacial implants.

2. 2. The implant of claim 1, wherein the curvature is preoperatively configured to adapt the implant to compensate for or augment the elevation of the soft tissue layer by supporting the soft tissue layer in place of at least the craniomaxillofacial bone, the support being asymmetrical from the support provided by a contralateral portion of the craniomaxillofacial bone.

3. The implant of claim 1 , wherein the soft tissue layer is one or more of muscle, fat, and skin.

4. The implant of claim 1 , wherein the plate is also porous.

5. 5. The implant of claim 4, further comprising a pre-operatively configured mechanical reinforcement.

6. The implant of claim 1 , wherein the mechanical reinforcement locally fills the pores of the plate.

7. The implant of any one of claims 1-6, wherein the curvature is preoperatively configured to adapt the implant to support the soft tissue layer by receiving the soft tissue layer in place of at least the craniomaxillofacial bone.

8. 7. The implant of claim 1, wherein the curvature is pre-operatively configured to adapt the implant to support the soft tissue layer by elevating the soft tissue layer above at least the craniomaxillofacial bone.

9. The implant for reconstructing a defective craniomaxillofacial bone and a defective soft tissue layer overlying the defective craniomaxillofacial bone, wherein the warping comprises: The implant is set on and supported by at least the non-defective portion of the defective craniomaxillofacial bone and / or the defective portion of the defective soft tissue layer; The defective craniomaxillofacial bone defect portion, and the defective portion of the defective soft tissue layer 7. The implant of claim 1, wherein the implant is pre-operatively configured to adapt the implant to support the missing soft tissue layer in place of the missing soft tissue layer.

10. 10. The implant of claim 9, wherein the missing craniomaxillofacial bone is the cranium and the missing soft tissue layer includes overlying temporalis muscle and fat.

11. 11. The implant of claim 10, wherein the missing craniomaxillofacial bone is the maxilla or zygomatic bone, and the missing soft tissue layer includes the overlying zygomatic major muscle, zygomatic minor muscle, and fat.

12. 10. The implant of claim 9, wherein the missing craniomaxillofacial bone is the orbit and the missing soft tissue layer includes the overlying orbicularis oculi muscle, inferior rectus muscle, inferior oblique muscle, eyeball, and fat.

13. The implant for cosmetic surgery, wherein the warpage is a dental implant positioned on and supported by at least the craniomaxillofacial bone and / or the soft tissue layer; The implant of any one of claims 1-6, wherein the implant is preoperatively configured to adapt the implant to modify the apparent contours of the craniomaxillofacial bones by supporting the soft tissue layer in place of at least the craniomaxillofacial bones.

14. The implant of claim 13, wherein the cosmetic surgery is performed on the maxilla or cheekbone.

15. The implant of claim 14, wherein the cosmetic surgery is performed on the mandible.

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