# US 10,945,848 B2 · Apparatus, method and system for providing customizable bone implants

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 10,945,848 B2
- Document ID: US10945848B2
- Status: Granted
- Kind: B2
- Application number: 16/153,334
- Filed: 2018-10-05
- Published: 2019-02-28
- Granted: 2021-03-16
- Earliest claimed: 2016-04-07
- Assignees: Icahn School of Medicine at Mount Sinai
- Applicants: Icahn School of Medicine At Mount Sinai
- Inventors: Douglas B. Unis; Sulaiman Somani; Anthony B. Costa
- Web page: https://patentgrep.com/patent/US10945848B2

## CPC

- A61F 2/30942: {for designing or making customized prostheses, e.g. using templates, CT or NMR scans, finite-element analysis or CAD-CAM techniques}
- A61F 2/28: Bones
- A61F 2/30: Joints
- A61F 2/3601: {for replacing only the epiphyseal or metaphyseal parts of the femur, e.g. endoprosthetic femoral heads or necks directly fixed to the natural femur by internal fixation devices (non-prosthetic internal fixation devices for the femoral head or neck A61B17/74)}
- B22F 10/80: Data acquisition or data processing
- B33Y 30/00: Apparatus for additive manufacturing; Details thereof or accessories therefor
- B33Y 50/00: Data acquisition or data processing for additive manufacturing
- G05B 19/4099: Surface or curve machining, making three-dimensional [3D] objects, e.g. desktop manufacturing
- G06F 30/20: Design optimisation, verification or simulation (optimisation, verification or simulation of circuit designs G06F30/30)
- A61F 2002/3092: {having an open-celled or open-pored structure}
- A61F 2002/30943: {using mathematical models}
- A61F 2002/30948: {using computerized tomography, i.e. CT scans}
- A61F 2002/30952: {using CAD-CAM techniques or NC-techniques}
- A61F 2002/30953: {using a remote computer network, e.g. Internet}
- A61F 2002/30957: {using a positive or a negative model, e.g. moulds}
- A61F 2002/3096: {trimmed or cut to a customised size}
- A61F 2002/30962: {using stereolithography}
- A61F 2002/30968: {Sintering}
- A61F 2002/3097: {using laser}
- A61F 2002/30985: {using three dimensional printing [3DP]}
- B22F 10/00: Additive manufacturing of workpieces or articles from metallic powder (apparatus or devices therefor B22F12/00)
- B22F 10/28: Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM]
- G05B 2219/35134: 3-D cad-cam
- G05B 2219/49007: Making, forming 3-D object, model, surface
- Y02P 10/25: Process efficiency
- A61F: FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS (dental prosthetics A61C)
- B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B33Y: ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G)
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

The present invention includes a method for generating a three-dimensional model of a bone and generating a cut plan for excavating a portion of the bone according to the cut plan to allow the insertion of a custom implant. In a particular arrangement, the method also includes excavating the bone with an autonomous extremity excavator utilizing the cut plan generated by a processor. In a further arrangement, the method includes generating a digital model of a custom implant and generating, using the digital model, a physical model sharing the same dimensions as the digital module using manufacturing device.

## Claims

### Claim 1

A method for digitally generating a custom femoral stem, the method comprising the steps of:
generating a three-dimensional digital representation of a patient's femur; wherein the three-dimensional digital representation of the femur includes at least data identifying different areas of relative bone density and porosity of the femur; and
generating a three-dimensional model of the custom femoral stem for use as an implant using at least the data obtained from the three-dimensional digital representation of the patient's femur having the at least data identifying different areas of relative bone density and porosity of the patient's femur.

### Claim 2 (depends on 1)

The method of claim 1, wherein the step of generating the three-dimensional digital representation comprises the step of performing a scan of the patient's femur using a medical scanning device.

### Claim 3 (depends on 2)

The method of claim 2, wherein the medical scanning device is one of a computerized axial tomography (CAT or CT) scan device and a magnetic resonance imaging (MRI) scan device.

### Claim 4 (depends on 1)

The method of claim 1, wherein the step of generating the three-dimensional digital representation comprises the step of identifying and segmenting voxels or pixels representing the femur from non-femur voxel or pixel data to allow for identification of cortical bone boundaries.

### Claim 5 (depends on 4)

The method of claim 4, wherein the step of identifying and segmenting comprises the step of segmenting femur voxel or pixel data from the remaining voxel or pixel data using a modified hybrid intensity-based segmentation method and an active shape modeling (ASM) segmentation method.

### Claim 6 (depends on 5)

The method of claim 5, further including the step of isolating voxel or pixel data that corresponds to a head of the femur.

### Claim 7 (depends on 6)

The method of claim 6, wherein the step of isolating voxel or pixel data comprises the step of implementing a Hough transform algorithm to localize the head of the femur.

### Claim 8 (depends on 7)

The method of claim 7, further including the step of using a Hough transform algorithm to identify a femoral neck portion.

### Claim 9 (depends on 8)

The method of claim 8, further including the step of upon identification of boundaries of the femoral neck, eroding a joint space around the head of the femur to leave an isolated femoral mask.

### Claim 10 (depends on 4)

The method of claim 4, further including the step of generating an initial femur mask based on a double threshold technique that includes a high threshold value and a low threshold value that are used to determine edge voxels or pixels on the initial femur mask by classifying voxels or pixels that have values above the high threshold value as representing an edge of the femur.

### Claim 11 (depends on 1)

The method of claim 1, wherein the step of generating the three-dimensional model comprises the three-dimensional model comprising a femoral head and neck for use as the implant using at least the data obtained from the three-dimensional digital representation of a patient's femur.

### Claim 12 (depends on 1)

The method of claim 1, wherein the step of generating the three-dimensional model comprises the three-dimensional model comprising a femoral head and neck implant using at least the data obtained from the three-dimensional digital representation of a patient's femur where the femoral head and neck match the natural position of the patient's femoral head and neck.

### Claim 13 (depends on 1)

The method of claim 1, wherein the step of generating the three-dimensional model comprises the three-dimensional model comprising a femoral head and neck implant using at least the data obtained from the three-dimensional digital representation of a patient's femur where the femoral stem, femoral head and neck implant is operable to correct anteversion and restore the patient's biomechanics.

### Claim 14

A method for generating a custom implant for insertion into a patient, the method comprising the steps of:
generating, using a bone scanning device, a three-dimensional digital representation of a selected bone of the patient; by scanning the patient's bone, wherein the digital representation of the bone includes at least data identifying different areas of relative bone density and porosity of the scanned patient's bone;
generating a three-dimensional model of the custom implant using at least the data obtained from the three-dimensional digital representation of the selected bone of the patient having the at least data identifying different areas of relative bone density and porosity of the scanned patient's bone; and
manufacturing, a physical copy of the three-dimensional model of the custom implant which includes substantially similar areas of relative density and porosity as the scanned bone.

### Claim 15 (depends on 14)

The method of claim 14, wherein the bone comprises a femur and the custom implant comprises a custom femoral stem.

### Claim 16 (depends on 15)

The method of claim 15, wherein the physical copy of the three-dimensional model of the custom femoral stem is formed such that a percent contact between an inner surface of the cortical bone region of the patient's femur and an outer surface of the implant is at least 50%.

### Claim 17 (depends on 16)

The method of claim 16, wherein percent contact is at least 70%.

### Claim 18 (depends on 16)

The method of claim 16, wherein the percent contact is at least 30%.

### Claim 19 (depends on 16)

The method of claim 16, wherein a length of the physical copy of the three-dimensional model of the custom femoral stem is selected such that it does not extend more than about 5mm below a lesser trochanter of the patient.

### Claim 20 (depends on 19)

The method of claim 19, wherein the length of the physical copy of the three-dimensional model of the custom femoral stem is selected such that it does not extend more than about 2 mm below the lesser trochanter of the patient.

### Claim 21 (depends on 16)

The method of claim 16, wherein the length of the physical copy of the three-dimensional model of the custom femoral stem is selected such that it does not exceed a length of the patient's lesser trochanter.

### Claim 22 (depends on 15)

The method of claim 15, wherein a stiffness of the physical copy of the three-dimensional model of the custom femoral stem is substantially about equal to a stiffness of a bone portion that the physical copy of the three-dimensional model of the custom femoral stem is configured to be mated with.

### Claim 23

A method for generating a custom implant in the form of a femoral stem for insertion into a patient and for calculating an implant cavity for receiving the implant, the method comprising the steps of:
generating, using a bone scanning device, a three-dimensional digital representation of a patient's femur; by scanning the femur wherein the digital representation of the femur includes at least data identifying different areas of relative bone density and porosity of the scanned femur;
generating a three-dimensional model of the femoral stem using at least the data obtained from the three-dimensional digital representation of the patient's femur having the at least data identifying different areas of relative bone density and porosity, wherein the three-dimensional model of the femoral stem includes substantially similar areas of relative density and porosity as the scanned femur;
manufacturing the custom implant which comprises a physical copy of the three-dimensional model of the femoral stem; and
based on both the three-dimensional digital representation of the patient's femur and on the three-dimensional model of the femoral stem, generating a cut plan which comprises a data file that contains an instruction set for removing bone from the femur of the patient so as to permit insertion of the custom implant.

### Claim 24 (depends on 23)

The method of claim 23, further including the steps of: identifying an optimal location for the implant by performing the step of: (a) identifying a location of the three-dimensional digital representation of the femur where the custom implant would encounter a greatest amount of cortical bone material upon insertion; or (b) identifying a location where the custom implant having a minimum length can be inserted while maintaining a predetermined level of cortical bone contact.

### Claim 25 (depends on 23)

The method of claim 23, further including the steps of: identifying an optimal location for the custom implant by selecting a location of the three-dimensional digital representation of the femur at which a minimum thickness of cortical bone will remain post excavation of a space for receiving the implant.

### Claim 26

A system for generating a custom implant, the system comprising:
a bone scanner that is configured to obtain bone data from a selected bone of a patient;
a processor configured with code executing therein to transform the bone data into a three-dimensional representation of the patient's bone, the processor further configured to generate, using a stem modeling application, a three-dimensional digital model of the custom implant for insertion into the bone, the three-dimensional representation of the bone including providing different areas of relative porosity and density, the processor additionally configured to generate an excavation protocol for excavating bone from the selected bone such that a percent contact between an inner surface of a cortical bone region in the patient's bone and an outer surface of the custom implant is at least 50%;
a manufacturing device configured to generate the custom implant from the three-dimensional digital model of the custom implant; and
a processor controlled bone excavation device configured to excavate bone from the patient's bone according to an excavation protocol.

### Claim 27 (depends on 26)

The system of claim 26, wherein the bone comprises a femur and the custom implant comprises a femoral stem.

### Claim 28 (depends on 27)

The system of claim 27, wherein the custom femoral stem is configured such that a length thereof does not extend more than about 10 mm below a lesser trochanter of the patient and is further configured to achieve a percent contact between an inner surface of a cortical bone region of the patient's femur and an outer surface of the custom femoral stem is at least 60%.

### Claim 29 (depends on 28)

The system of claim 28, wherein the percent contact is at least 70%.

### Claim 30 (depends on 28)

The system of claim 28, wherein the percent contact is at least 30%.

### Claim 31 (depends on 27)

The system of claim 27, wherein a length of the custom femoral stem is selected such that it does not extend more than about 5 mm below a lesser trochanter of the patient.

### Claim 32 (depends on 27)

The system of claim 27, wherein a length of custom femoral stem is selected such that it does not extend more than about 2 mm below the lesser trochanter of the patient.

### Claim 33 (depends on 27)

The system of claim 27, wherein a length of the custom femoral stem is selected such that it does not exceed a length of the patient's lesser trochanter.

### Claim 34

A computer implemented method for generating a three-dimensional model of a custom femoral stem, the method comprising the steps of:
accessing a three-dimensional scan of a femur of a patient, wherein the scan is configured to provide information regarding the porosity and pore size of the scanned femur;
generating, using code executing in a processor, a three-dimensional model of the patient's femur using at least the information obtained from the three-dimensional scan having the porosity and pore size of the scanned femur of the patient, where the three-dimensional model of the femur includes an extraction portion and a remaining portion, the extraction portion corresponding to an anticipated removal of material from the femur; and
building, using code executing in the processor, a three-dimensional model of the custom femoral stem configured to replace the extraction portion in the three-dimensional model of the femur, wherein the three-dimensional model of the custom femoral stem is configured to match the porosity and pore size features of the femur model using finite element analysis.

### Claim 35 (depends on 34)

The method of claim 34, further comprising:
outputting a cut file, wherein the cut file contains data on the material to be removed from the femur, and a make file, wherein the make file includes data on generating a physical copy of the three-dimensional model of the custom femoral stem for insertion into the remaining portion of the femur; and
extracting material from the femur using a computer control bone evacuation device configured to implement the cut file.

### Claim 36

A computer implemented method for generating a three-dimensional model of a femur from scan data comprising the steps of:
accessing scan data from a bone scanning device, wherein the scan data includes a collection of pixel data depicting the femur;
applying a threshold mask to the pixels representing the femur within the scan data;
augmenting the threshold mask applied to pixels representing a femoral head using a shape modeling algorithm;
identifying the pixels corresponding to a femoral neck using an intensity threshold operation;
eroding the pixel intensity values for pixels not corresponding to the femoral head and the femoral neck and updating the pixels classified by the shape modeling algorithm; and
outputting a three-dimensional model of the femur.

### Claim 37 (depends on 36)

The method of claim 36, wherein the shape modeling algorithm is a Hough transform algorithm.

### Claim 38 (depends on 37)

The method of claim 37, wherein the Hough transform algorithm utilizes an anisotropic sphere, the semi-axes of which are set based on the scan data spacing.

### Claim 39 (depends on 38)

The method of claim 38, wherein, the Hough transform algorithm includes cost functions that operate to penalize a four-dimensional hypersurface in a Hough space for radii of the anisotropic sphere above a pre-determined value.

### Claim 40

A method for digitally generating a custom femoral head and neck, the method comprising the steps of:
generating a three-dimensional digital representation of a patient's femur;
wherein the digital representation of the femur includes at least data identifying different areas of relative bone density and porosity of the femur; and
generating a three-dimensional model of a femoral head and neck for use as an implant using at least the data obtained from the three-dimensional digital representation of the patient's femur having the at least data identifying different areas of relative bone density and porosity of the femur.

### Claim 41 (depends on 40)

The method of claim 40, wherein the step of generating the three-dimensional model comprises the three-dimensional model comprising a femoral stem for use as the implant using at least the data obtained from the three-dimensional digital representation of a patient's femur.

### Claim 42 (depends on 40)

The method of claim 40, wherein the step of generating the three-dimensional model comprises the three-dimensional model comprising a femoral stem for use as the implant using at least the data obtained from the three-dimensional digital representation of a patient's femur where the femoral head and neck match the natural position of the patient's femoral head and neck.

### Claim 43 (depends on 40)

The method of claim 40, wherein the step of generating the three-dimensional model comprises the three-dimensional model comprising a femoral stem for use in the implant using at least the data obtained from the three-dimensional digital representation of a patient's femur where the femoral stem, femoral head and neck implant is operable to correct anteversion and restore the patient's biomechanics.