-i-
`
`Smith & Nephew Ex. 1007
`IPR Petition - USP 9,295,482
`
`

`
`FOR THE PURPOSES OF INFORMATION ONLY
`
`Codes used to identify States party to the PCT on the front pages of pamphlets publishing international
`applications under the PCT.
`
`AT
`AU
`BB
`BE
`BF
`BG
`BJ-
`BR
`BY
`CA
`CF
`CG
`cu
`CI
`CM
`CN
`cs
`cz
`DE
`DK
`ES
`FI
`FR
`GA
`
`Austria
`Australia
`Barbados
`Belgium
`Burkina Faso
`Bulgaria
`Benin
`Brazil
`Belarus
`Canada
`Central African Republic
`Congo
`Switzerland
`Cote d’Ivoire
`Cameroon
`China
`Czechoslovakia
`Czech Republic
`Gennany
`Denmark
`Spain
`Finland
`France
`Gabon
`
`Mauritania
`Malawi
`Niger
`Netherlands
`Norway
`New Zealand
`Poland
`Portugal
`Romania
`Russian Federation
`Sudan
`Sweden
`Slovenia
`Slovakia
`Senegal
`Chad
`Togo
`Tajikistan
`Trinidad and Tobago
`Ukraine
`United States of America
`Uzbekistan
`Viet Nam
`
`United Kingdom
`Georgia
`Guinea
`Greece
`Hungary
`Ireland
`Italy
`Japan
`Kenya
`Kyrgystan
`Democratic People‘s Republic
`of Korea
`Republic of Korea
`Kazakhstan
`Liechtenstein
`Sri Lanka
`Luxembourg
`Latvia
`Monaco
`Republic of Moldova
`Madagascar
`Mali
`Mongolia
`
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`-ii-
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`WO 95/28688
`
`PCT/BE95l00033
`
`Method for making a perfected medical model on the basis
`
`of digital image information of a part of the body.
`
`1The invention concerns a method for making a perfected
`
`medical model on the basis of digital image information
`
`of a part of
`
`the body, according to which this image
`
`information of a part of the body is converted, by means
`
`of what
`is called the rapid prototyping technique and
`thus with a processing unit and a rapid prototyping
`
`machine,
`
`into a basic model of which at
`
`least a part
`
`perfectly shows the positive or negative form of at least
`
`a part of the part of the body.
`
`By rapid prototyping technique should be understood all
`
`techniques whereby an object is built layer by layer or
`
`point per point by adding or hardening material
`
`(also
`
`called free—form manufacturing).
`
`The best
`
`known
`
`techniques of
`
`this type are:
`
`stereo lithography and
`
`related techniques, whereby for example a basin with
`
`liquid synthetic material is selectively cured layer by
`
`layer by means of a computer—controlled electromagnetic
`beam; selective laser sintering, whereby powder particles
`
`are sintered by means of an electromagnetic beam or are
`
`welded together according to a specific pattern; or fused
`
`deposition modelling, whereby a synthetic material
`
`is
`
`fused and is stacked according to a line pattern.
`
`10
`
`15
`
`20
`
`25
`
`30
`
`The digital
`
`image
`
`information can be ‘provided by a
`
`computer tomography scanner.
`
`The model produced up to now according to the above-
`
`mentioned technique, can be a model which is an exact
`
`-1-
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`

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`PCT/BE95/00033
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`2
`
`copy of
`
`the part of
`
`the body,
`
`for example a piece of
`
`bone,
`
`and
`
`upon
`
`which
`
`a
`
`surgery operation can
`
`be
`
`practised, or it can be a prosthesis which fits perfectly
`
`to the part of the body.
`
`However,
`
`the models produced up to now,
`
`including three-
`
`dimensional
`
`images, do not
`
`take advantage of all
`
`the
`
`information contained in the image information.
`
`They
`
`form a perfect copy of the part of the body, but they do
`
`not contain any additional functional elements.
`
`Functional elements,
`
`such as an opening indicating the
`
`place and direction for boring,
`
`can be added manually,
`
`but not as a function of the image information.
`
`At the
`
`time when these models are made,
`
`the grey value data of
`
`the image information are lost._
`
`However,
`
`these grey
`
`value data contain clinical data which are important for
`
`the use of
`
`the models.
`
`Such clinical data are for
`
`example the muscles and tendons which have to be taken
`
`into account when designing a prosthesis.
`
`and tendons are visible in the images,
`
`These muscles
`
`but not
`
`in the
`
`three—dimensional model, nor when working with segmented
`
`contours/surfaces in CAD-applications.
`
`The manipulation of digital
`
`image data during the
`
`preparation of a surgery operation, for example, is known
`
`for example,
`to determine the
`as such.
`It is possible,
`position and direction‘of an implant on the images or to’
`
`simulate surgeries. However, there is no connection with
`
`reality and, by lack of reference,
`
`these prepared image
`
`data cannot be used in practice.
`
`The image information
`
`is not used to the full.
`
`As for the application of dental implants, attempts have
`
`10
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`15
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`20
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`25
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`30
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`-2-
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`

`
`WO 95128688
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`PCT/BE95/00033
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`3
`
`already been made
`
`to use
`
`teeth of
`
`a
`
`provisional
`
`prosthesis as a reference.
`
`This provisional prosthesis
`
`is made on the basis of a mould. With a reconstruction
`
`by means of computer
`
`tomography scanner images on the
`
`basis of planes in which the bone is clearly visible,
`one can see whether the
`
`_what is called a dental scan,
`. position and the angle of
`the provisional
`
`teeth are
`
`correct in relation to the underlying bone, and one can
`
`make corrections.
`
`However,
`
`this is a
`
`time—consuming
`
`10
`
`method.
`
`15
`
`20
`
`25
`
`30
`
`‘Sometimes, a template is made on the basis of the mould
`
`and this template is used during the surgery.
`
`Only
`
`surface data are used hereby,
`
`so that part of
`
`the
`
`information of the dental scan remains unused.
`
`Another method consists in making a model of the jaw by
`
`means of the rapid prototyping technique and to make a
`
`template on the basis of this model which is used during
`
`the surgery. The information of the digital image of the
`
`teeth (the dental scan) cannot be used either with this
`method.
`
`The invention aims to remedy these disadvantages and to
`
`provide a method for making a perfected medical model on
`
`the basis of digital
`
`image information of a body part
`
`whereby the image information can be optimally used and
`
`can be put to use in practice.
`
`'
`
`This aim is reached according to the invention as at
`
`least.
`
`a
`
`functional element. with a useful
`
`function is
`
`A added to the basic model,
`
`as a function of the digital
`
`information and possibly as
`
`a
`
`function of additional
`
`external information.
`
`-3-
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`PCT/BE95/00033
`
`4
`
`By subsequently converting the image with the additional
`
`information in information for the control of a rapid
`
`"prototyping machine,
`
`there is a feedback of the medical
`
`data to reality and a perfected model is obtained which
`
`does not only have the shape of a certain part of the
`
`body,
`
`such as a ragged bone shape,
`
`and thus provides a
`
`perfect
`
`reference,
`
`but which also contains artificial
`
`elements which are added as a function of
`
`the image
`
`information and of possible new additional information,
`
`10
`
`and which have a useful function.
`
`In
`
`a particular
`
`embodiment
`
`of
`
`the
`
`invention,
`
`the
`
`functional element is added as a function of the digital
`
`image information in the form in which all medical data _
`
`15
`
`are visible.
`
`Such a form of the image information consists of the grey
`
`value information.
`
`20
`
`25
`
`In
`
`a
`
`peculiar
`
`embodiment
`
`of
`
`the
`
`invention,
`
`the
`
`information on the basis of which the functional element
`
`is determined is processed factually in the perfected
`
`model by means of a voxel oriented computer system.
`
`Via contour generation (segmentation/interpolation), one
`
`can switch from image processing to for example stereo
`
`lithography.
`
`Possible new information added from outside to determine
`
`the functional element must
`voxels or contours.
`
`30
`
`then also be presented as
`
`The functional element with a useful function can be a
`
`shape, a colour or a texture.
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`-4-
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`PCT/BE95/00033
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`5
`
`This useful function can be the indication of a position,
`a direction,
`a length or an angle which are important
`
`during a surgery, the formation of a point of attachment,
`
`the formation of
`
`a filling for
`
`a certain defect,
`
`a
`
`prosthetic function, etc.
`
`;A-useful function can for example also be facilitating
`the identification of a model or of model parts for a
`
`certain patient by providing an inscription or a label
`
`which may not restrict
`
`the diagnostic or
`
`functional
`
`10
`
`qualities.
`
`The method can be used in numerous applications.
`
`15
`
`20
`
`Thus, it can be usefully applied in combination with the
`
`already
`
`applied computer
`
`aided
`
`surgery
`
`simulation,
`
`whereby bone segments_are cut and moved at a certain
`
`-angle and over a certain distance.
`
`With the help of the
`
`method,
`
`templates and jigs can be made which provide a
`
`perfect reference on the one hand and indicate angles and
`
`movements on the other hand.
`
`The method can also be used for the preparation of tooth
`
`implants, whereby the perfected medical model
`
`is a
`
`template and the functional element
`
`is an opening or
`
`.25
`
`notch on the place where drilling is required, or for
`
`making a knee prosthesis, whereby the basic model is a
`
`metal base which can be joined to
`
`a sawn off tibia or
`
`femur and whereby the functional elements are orientation
`
`pins and/or fastening pins which stand on said base and
`
`'30
`
`which position and/or fix a prosthesis. Also an actual
`prosthesis can be made according to the method, part of
`
`which fits perfectly to existing bone and another part of
`
`which forms
`
`the functional element with a prosthetic
`
`function.
`
`-5-
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`WO 95/28688
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`PCT/BE95/00033
`
`6
`
`In order to better explain the characteristics of
`
`the
`
`invention,
`
`the following preferred embodiments of
`
`a
`
`"method for making a perfected medical model on the basis
`
`of digital image information of a part of the body are
`
`given as an example only without being limitative in any
`
`way, with reference to the accompanying drawings, in which:
`
`figure 1 shows a general block diagram of a method
`
`for making a perfected medical model according to
`
`the invention;
`
`figure 2 schematically shows how a perfected medical
`
`model is made on the basis of the image;
`
`figure 3 schematically shows how another form of a
`
`perfected medical model
`
`is made according to the
`
`method of the invention;
`
`figures 4
`
`to 8 schematically show how yet other
`
`forms
`
`of
`
`perfected ‘medical
`
`models
`
`for
`
`other
`
`applications can be made according to the invention.
`
`As is schematically represented in figure 1,
`
`images 3 are
`
`made of a part of the body of a patient 1 by means of a
`
`computer tomography scanner 2 or any other digital image’
`
`processing unit
`
`such as
`
`a Magnetic Resonance
`
`Image
`
`machine,
`
`which
`
`thus
`
`contain
`
`digitized medical
`
`information.,
`
`Instead of converting these images
`
`in for example a
`
`three—dimensional image or a dental scan and subsequently
`
`either making a model by means of rapid prototyping or
`
`processing the images,
`
`the image data will be first
`
`10
`
`15
`
`20
`
`z 25
`
`30
`
`-6-
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`W0 95/28688
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`PCTlBE95/00033
`
`7
`
`processed in a processing unit 4, after which a perfected
`
`model 6 is made with these processed digitized image data
`
`by means of rapid prototyping with a rapid prototyping
`
`machine 5.
`
`Use can be made
`
`for this operation of a
`
`visual
`
`three—dimensional
`
`image 17 or a dental scan 18
`
`;which is derived in the usual manner from the images 3.
`
`This three—dimensional
`
`image 17 and this dental scan 18
`
`are represented in figure 1 by means of a dashed line.
`
`10
`
`What is characteristic is that the model 6 can be used in
`
`reality on the patient 1 or in other words that the cycle
`
`represented in figure 1
`
`is completed.
`
`In this figure,
`
`everything ‘that
`
`is situated. under
`
`‘the dashed line 19
`
`represents reality, and everything that is situated above
`
`15
`
`it is immaterial information.
`
`20
`
`25
`
`30
`
`The processing or preparation includes the manipulation
`
`of medical digital image data, possibly with additional
`
`digital information from outside,
`
`in such a way that an
`
`artificial, functional element 10 with a useful function
`
`is added to the produced basic model 9.
`
`The processing of existing and possibly new information
`
`or
`
`the "design"
`
`is carried out with a voxel-oriented
`
`system in the processing unit 4, i.e. by means of voxels
`
`or contours, whereby "voxels or groups of voxels are
`
`indicated in the images
`
`3.
`
`A voxel his
`
`a
`
`three-
`
`The grey
`dimensional pixel and thus represents a cube.
`value data of
`the voxels can be-used to obtain still
`
`higher resolutions and accuracies.
`
`The processing unit
`
`4 which controls the rapid prototyping machine can help
`
`during the processing by carrying out operations on these_
`
`voxels which are standard operations in three—dimensional
`
`image processing,
`
`such as thresholding (segmentation on’
`
`-7-
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`WO 95/28688
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`PCTlBE95/00033
`
`8
`
`three-dimensional reduction,
`the basis of grey values),
`expansion,
`region growing, boolean operations such as
`
`adding and subtracting, projections, etc.
`
`If external
`
`technical elements are added,
`
`for example
`
`coming
`
`from a
`
`CAD
`
`system,
`
`these
`
`elements must
`
`be
`
`represented as voxels or contours as well. This can be
`
`easily done by means of
`
`cross
`
`section and
`
`shading
`
`algorithms.
`
`After the interactive processing of the image information
`
`(for
`
`example
`
`rotations,
`
`translations, etc.),
`
`it
`
`is
`
`possible to go back to the original CAD data to obtain a
`
`higher resolution and accuracy of the functional element.
`
`10
`
`15
`
`Figure 2 shows an enlarged representation of one of the
`
`images 7 with grey values, derived in the processing unit
`
`20
`
`4 in the form of voxels from the images 3 of a bone 20
`produced by the scanner 2.
`Through processing in the
`
`25
`
`30
`
`processing unit
`
`4 are made negative images
`
`8
`
`in voxel
`
`form which fit perfectly to the images 7 and thus to the
`
`bone. Moreover,
`
`the image 11 of a functional element 10
`
`is provided in voxel form in the images 8.
`
`The images 8
`
`coincide with a reference part which forms a negative
`
`basic model
`
`9 which fits perfectly to the bone,
`
`which
`
`basic model 9,
`
`together with the functional element 10,
`
`forms the perfected model 6.
`
`In figure 2 is represented by means of a dashed line 21
`
`the boundary between what is reality (underneath it) and
`what
`is image information (above it), whereas what
`is
`
`situated above the dashed line 22 is represented enlarged
`
`and in voxel form.
`
`-8-
`
`

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`WO 95/28688
`
`PCT/BE95l00033
`
`9
`
`When providing the image 11 of the functional element 10
`
`in voxel
`
`form, one can take into account all medical
`
`information contained in the images 7.
`
`Via
`
`stereo
`
`lithography,
`
`the images 8, with on top of them the images
`
`11 of
`
`the functional element 10, are converted in the
`
`.three-dimensional, factual, perfected model 6 which can
`be placed as a template on the bone of the patient
`1
`
`during a surgery and which fits perfectly to it.
`
`The
`
`useful function of the functional element 10 can then be
`
`10
`
`put
`
`to use.
`
`The information of the scanner 2 and the
`
`information
`
`of
`
`the
`
`position and direction
`
`of
`
`the
`
`functional element 10 based upon it, are in this way used
`
`to the full and translated into reality.
`
`15
`
`In order to pass from the information of the processing
`
`unit 4 to the rapid processing technique, one can proceed
`
`as follows:
`
`the information or data set,
`
`consisting of voxels and.
`
`20
`
`contours, of the processing unit 4 is converted into a
`
`set of contours per layer height. This is done by means
`
`of
`
`a
`
`screen which is finer
`
`than the screen of
`
`the
`
`original images 3, since the rapid prototyping techniques
`
`have a higher resolution than the scanner 2.
`
`In order to
`
`25
`
`obtain this finer screen, use is made of the grey value
`
`information in the images 3. Thus, a pixel or voxel can
`
`partly belong to the perfected model
`
`6 and partly not.
`When
`
`"This phenomenon is known as partial volume effect.
`
`there are only two materials in one pixel or voxel, a
`
`30
`
`contour line can be calculated in between the pixels by
`
`means of interpolation, as described by B. Swaelens and
`
`others in "Medical Applications of Rapid Prototyping
`
`Techniques", p.
`
`107-120 of
`
`"Proceedings of
`
`the Fourth
`
`International Conference on Rapid Prototyping, Dayton,
`
`-9-
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`

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`WO 95/28688
`
`PCT/BE95/00033
`
`10
`
`OH,
`
`June 14-17,
`
`1993".
`
`Said higher
`
`resolution is
`
`important
`
`to make the designed model fit well onto the
`
`part of
`
`the body.
`
`Once
`
`the contours per
`
`layer are
`
`calculated,
`
`they are interpolated in the third dimension
`
`up to the layer height which is suitable for the rapid
`
`. prototyping technique.
`
`This
`
`layer height
`
`is usually
`
`significantly lower than the scan distance.
`
`10
`
`15
`
`20
`
`Another method consists in converting the above—mentioned
`
`data set into a surface description with for example one
`Such
`
`of the usual formats such as triangle format (STL).
`
`descriptions are used ix) calculate sections which are
`
`made by the rapid prototyping machine 5. Here also, it
`
`is possible to work with sub—voxel resolution.
`
`According to a third method,
`
`the medical data or digital
`
`information is converted from the processing unit 4 to a
`
`CAD system.
`
`This
`
`is again approached by nmans of a
`
`surface description and by calculating the sections.
`
`It
`
`is possible to further add elements in the CAD system,
`
`but not as a function of the image information.
`
`The functional element 10 with a useful function can be
`
`a shape,
`
`a colour, a texture or another characteristic
`
`25
`
`element.
`
`The useful function of the element 10 can be
`
`the indication of a place where, a direction in which, a
`
`length over which or an angle at which one must cut,
`
`saw
`
`or drill;
`
`it can also be :3 point of attachment,
`
`the
`
`"filling of an existing defect,
`an identification.
`
`30
`
`a prosthetic function or
`
`In the embodiment represented in figure 2,
`
`the perfected
`
`model 6 is a template and the functional element 10 is an
`
`opening which indicates the position and direction for
`
`-10-
`
`-10-
`
`

`
`WO 95/28688
`
`PCT/BE95/00033
`
`11
`
`the boring bit of a boring machine.
`
`The basic model
`
`9
`
`forms a reference part. The thickness of the basic model
`9.at the height of the opening determines the depth of
`hole.
`
`‘The method can be used for
`
`the preparation of
`
`tooth
`
`implants.
`
`The position and’ the orientation of
`
`the
`
`implants, both in relation to the bone and in relation to
`
`the teeth,
`
`is very important. First, a dental scan is
`
`10
`
`made.
`
`Thanks
`
`to
`
`computer—aided preparations,
`
`the
`
`15
`
`20
`
`25
`
`30
`
`thickness, position, direction and length of an implant
`
`can be well planned.
`
`By making a template according to
`
`the invention as represented in figure 2, it is not only
`
`possible to match the planned size and length of
`
`the
`
`implant
`
`in reality, but also directly the position and
`
`direction.
`
`For we have a reference part formed by the
`
`basic model
`
`9 which fits perfectly to the bone and an
`
`element 10 which forms a guide for the boring bit with
`
`which the hole for the implant
`
`is drilled and which
`
`determines
`
`the position,
`
`direction and depth of said
`
`hole.
`
`Instead of directly making a negative perfected model 6,
`
`a positive model 13-14 of
`
`the bone can be made in the
`
`above-described manner,
`
`but
`
`containing
`
`information
`
`regarding the position, direction and depth of the drill
`
`hole to’ be made
`
`in the form of protrusions
`
`14
`
`as
`
`represented in figure 3.
`
`Only afterwards, a basic model
`
`9 is made as a reference part, for example manually, with
`
`openings as functional elements 10, as a negative mould
`of the positive model 13-14 as represented in figure 4.
`
`Another application resides
`
`in the production of
`
`a
`
`membrane for bone generation, whereby this membrane can
`
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`12
`
`form the reference part or basic model
`
`9
`
`and the
`
`functional element 10 a notch or incision as represented
`
`in figure 5. First, a positive intermediate model 15 is
`
`made on the basis of the images 3 of the scanner 2, via
`
`stereo lithography, consisting of a basic model 9 and the
`
`required bone elevation 16 as a first functional element
`
`10. Whereas,
`
`according’
`
`to known methods,
`
`said bone
`
`elevation is determined by realising the elevation in
`
`reality in a radiographically visible material, prior to
`
`the scanning,
`
`the elevation is calculated according to
`
`the invention by the processing unit 4 and imported in
`
`the medical information derived from the grey value data,
`
`either departing from an ideal bone shape stored in a
`
`memory of the processing unit 4 or interactively.
`
`A second functional element 10 can be possibly provided,
`
`namely a place indication, for example in the shape of a
`
`notch, there where the implant should come. This can be
`
`either
`
`done
`
`through
`
`the
`
`agency
`
`of
`
`the
`
`user
`
`or
`
`automatically by" means of
`
`a
`
`computer’ according to a
`
`stored program.
`
`In any case, it is preferably provided
`
`as a function of the grey value data in a dental scan.
`
`10
`
`15
`
`20
`
`From the intermediate model 15 is made a perfected model
`
`25
`
`6
`
`in the shape of a membrane by making a mould on the
`
`basis of the intermediate model 15 and by shaping a foil
`
`in the mould into a membrane.
`
`Just as the intermediate
`
`model 15,
`
`the membrane_is provided with a notch as a
`
`functional element 10 which has as a function to indicate
`
`30
`
`the place of the implant.
`
`In the case where the implant is provided together with
`
`the membrane, reference marks or sutures can be provided
`.as functional elements 10 in the above-described manner
`
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`13
`
`to position the membrane in the space where the bone will
`
`grow later.
`
`Another application of
`
`the method according to the
`
`invention consists in making prostheses.
`
`‘With a knee prosthesis,
`
`the sliding surface of both the
`
`femur and the tibia must be replaced by sawing away a
`
`piece and by "replacing this piece by a prosthesis.
`
`Hereby,
`
`it
`
`is
`
`important
`
`that
`
`the prosthesis
`
`fits
`
`correctly to the bone,
`
`especially on the side of
`
`the
`
`tibia, since there is only a thin wall of strong cortical
`
`bone
`
`there
`
`to support
`
`the prosthesis.
`
`When
`
`the
`
`prosthesis is too large, protruding edges form a problem.
`
`In the first place, an incision is indicated in voxel
`form in the images 7,
`there where the tibia or
`femur
`
`should be sawn.
`
`A first negative model 6 is made in the
`
`above—described manners which fits perfectly to the bone
`
`20, but which protrudes all round this bone 20 with an
`
`edge which is cut off by said incision.
`
`This edge then
`
`forms a functional element 10 which serves as a guide for
`
`the saw with which the incision is sawn during the
`
`10
`
`15
`
`20
`
`25
`
`surgery operation.
`
`The voxels
`
`above
`
`the
`
`incision are
`
`removed
`
`in the
`
`processing unit 4 and a base 12 is designed here as a
`
`reference part or basic model
`
`9 upon which orientation
`
`30
`
`pins are provided as
`
`functional elements
`
`10 by the
`
`processing unit 4.‘ On the basis of this design is made,
`
`for example by means of stereo lithography and casting,
`
`a real model 6 which fits correctly to the remaining part
`.of
`the bone 20 and which is provided with functional
`
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`elements 10 which are oriented in the right manner.
`
`14
`
`The base 12
`
`can be designed such that it penetrates
`
`partly in the bone
`
`20,
`
`and especially also partly
`
`surrounds the bone on the outside,
`
`as
`
`represented in
`
`figure 8. This largely increases the strength.
`
`On the basis of
`
`the negative model
`
`6 which forms the
`
`sawing template, and taking into account the thickness of
`
`the base and the position of the functional elements 10,
`a positive model can be made of the prosthesis itself.
`One can hereby depart from the real model 6 of the sawing
`
`template or preferably from the digital
`
`information
`
`thereof
`
`in the processing unit
`
`4
`
`and calculate the
`
`prosthesis with the latter to finally transform it via
`
`rapid prototyping in a real prosthesis. This prosthesis
`
`will also be provided with functional elements 10 which
`
`are complementary to those provided on the base 12.
`
`Instead, a standard prosthesis can be provided on the
`
`base 12, whereby the functional elements 10 on the basic
`
`model 9 formed by the base 12 need to be provided in this
`
`case as
`
`a
`
`function of complementary elements of
`
`the
`
`standard prosthesis.
`
`A hip prosthesis can be made in an analogous manner which
`
`fits perfectly to the femur shaft on one side and which
`
`contains a technical part with functional elements on the
`
`other side upon which the artificial femur head can be
`
`placed.
`
`In the images
`
`7
`
`can. be indicated.
`
`the ideal
`
`length and the direction.
`
`A prosthesis fitting perfectly to an existing structure
`on one side and bearing a technical part on the other
`
`10
`
`15
`
`20
`
`25
`
`30
`
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`
`15
`
`side which has a prosthetic function can also be used for
`
`dorsal vertebra. Grey value data, for example regarding
`
`the position of the nerves, can be used in the processing
`
`unit 4 for the design of the prosthesis.
`
`It is also easily possible to design prostheses according
`
`to the invention which are partly or entirely supported
`
`by weak parts.
`
`Such prostheses
`
`are
`
`for
`
`example
`
`obstructors or "bobbins" which are used to fill up the
`
`nasal cavities and sinuses after tissue and/or bone has
`
`been surgically removed.
`
`The weak parts can be crushed,
`
`and ideally some distance is kept
`
`from the bone parts.
`
`This_is possible according to the invention by slightly
`
`enlarging the bone parts in the processing unit 4 at the
`
`stage of the image processing.
`
`A technical part could
`
`possibly be designed as well onto which can be attached
`
`a prosthesis such as a dental prosthesis.
`
`10
`
`15
`
`The present
`
`invention is by no means
`
`limited.
`
`to the
`
`20
`
`above—described embodiments represented in the drawings;
`
`on the contrary,
`
`such a method for making a perfected
`
`medical model on the basis of digital image information
`
`of
`
`a part of
`
`the body can be made
`
`in all sorts of
`
`variants while still remaining within the scope of the
`
`25
`
`invention.
`
`-15-
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`16
`
`Claims.
`
`5
`
`10
`
`15
`
`20
`
`1. Method for making a perfected medical model on the
`
`basis of digital image information of a part of the body,
`
`according to which this image information of a part of
`
`the body is converted, by means of what
`
`is called the
`
`rapid prototyping technique and thus with a processing
`
`unit
`
`(4)
`
`and a rapid prototyping machine
`
`(5),
`
`into a
`
`basic model
`
`(9) of which at least a part perfectly shows
`
`the positive or negative form of at least a part of the
`
`part of
`
`the body, characterized in that at
`
`least
`
`a
`
`functional element
`
`(10) with a useful function is added
`
`to the basic model
`
`(6)
`
`as a function of
`
`the digital
`
`information and. possibly as
`
`a
`
`function of additional
`
`external information.
`
`’2. Method according to the preceding claim, characterized
`
`in that
`
`the functional
`
`element
`
`(10)
`
`is added as
`
`a
`
`function of the digital image information in the form in
`
`which all medical data are visible.
`
`3. Method according to any of
`
`the preceding’ claims,
`
`—25
`
`characterized in that the information, on the basis of
`
`which the functional element
`
`(10)
`
`is determined,
`
`is
`
`processed factually in the perfected model
`
`(6) by means
`
`of a voxel oriented computer system.
`
`30
`
`4. Method according to the preceding claim, characterized
`
`in that possible new information added from outside to
`
`determine the functional element
`
`(10)
`
`is also presented
`
`as voxels or contours.
`
`-15-
`
`-16-
`
`

`
`wo 95I28688 V
`
`PCT/BE95/00033
`
`17
`
`5. Method according" to any of
`
`the preceding claims,
`
`characterized in that a functional element (10) is added
`
`consisting of a shape, a colour or a texture.
`
`6. Method according’
`
`to any of
`
`the preceding’ claims,
`
`lcharacterized in that a functional element (10) is added
`whose useful
`function can be
`the
`indication of
`a
`
`position,
`
`a direction, a length or an angle which are
`
`important during a surgery,
`
`the formation of a point of
`
`attachment,
`
`the formation of
`
`a filling for a certain
`
`defect, a prosthetic function or an identification.
`
`7. Method according to claim 6, characterized in that a
`
`drilling or sawing template is made with a reference part
`
`as a basic model
`
`(9) which fits perfectly to a part of
`
`the body part
`
`and a guide for
`
`the instrument as
`
`a
`
`functional element (10).
`
`8. Method according to claim 6, characterized in that it
`
`is used for the preparation of tooth implants and in that
`
`a basic model
`
`(9)
`
`is made with a reference part and at
`
`least one functional element
`
`(10) via a dental scan (18)
`
`and simulation in different planes.
`
`9. Method according to claim 6, characterized in that a
`
`membrane
`
`for
`
`bone
`
`generation
`
`is
`
`formed
`
`and
`
`an ’
`
`intermediate model
`
`(15)
`
`is made first consisting of a
`
`basic model
`
`(9) with a required bone elevation (16) as a
`
`functional element (10), determined by means of the grey
`
`value images
`
`(7), after which, by means of a mould,
`
`a
`
`metal foil is transformed into a membrane containing the
`
`above-mentioned functional element (10).
`
`10. Method
`
`according to any of
`
`claims
`
`8
`
`and
`
`9,
`
`10
`
`15
`
`20
`
`25
`
`30
`
`-17-
`
`-17-
`
`

`
`WO 95/28688
`
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`
`18
`
`characterized in that a membrane for bone generation is
`
`formed and an intermediate model
`
`(15)
`
`is made first
`
`consisting of a basic model
`
`(9)
`
`with a notch or an
`
`incision as a functional element
`
`(10)
`
`to indicate the
`
`place of an implant, after which, by means of a mould, a
`| metal foil is transformed into a membrane containing the
`above—mentioned functional element (10).
`
`11. Method according to claim 6, characterized in that a
`
`10
`
`is made by first making a positive
`(6)
`perfected model
`model (13-14) of the structure containing information on
`
`a functional element
`
`(10) and by subsequently making a
`
`negative mould of it.
`
`15
`
`12. Method according to claim 6, characterized in that on
`
`the basis of the information of a bone (20)
`
`sawn off on
`
`one side, by means of the processing unit (4) and a rapid
`
`is made a base (12) as basic
`prototyping machine (5),
`model
`(9) which is provided with fastening pins and/or
`
`20
`
`orientation pins as functional elements (10) to position
`
`a prosthesis.
`
`13. Method according to claim 6, characterized in that a
`
`prosthesis is made supported by weak parts surrounding a
`bone (20), whereby a perfected model
`(6)
`is made on the
`
`25
`
`basis of
`
`the digital
`
`image
`
`information by
`
`slightly
`
`enlarging the bone parts in the processing unit
`
`(4) at
`
`the stage of the image processing.
`
`-13-
`
`-18-
`
`

`
`WO 95/28688
`
`PCT/BE95/00033
`
`1/3
`
`70
`
`9
`
`70
`
`.
`
`‘
`
`\‘
`
`
`
`-19-
`
`

`
`WO 95/28688
`
`PCT/BE95/00033
`
`IIIIII
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`---u u
`......
`
`'
`
`IIII
`II
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`I IIIIIII IIII
`-IIII
`
`
`
`.1
`
`________. ______..._____7
`Z7
`
` A
`
`RV
`
`-20-
`
`

`
`W0 95I28688
`
`PCT/BE95/00033
`
`
`
`" 3
`
`$7‘
`
`
`
`a\\\\15>‘\§\_\‘51\\\V
`W/////Z,
`
`
`
`
`
`
`-21-
`
`

`
`INTERNATIONAL SEARCH REPORT A
`
`"A. CLASSIFICATION OF sum:-zcr MATTER
`IPC 6
`G06T15/00
`
`According to International Patent Classification (lPC) or to both national classification and IPC
`B. FIELDS SEARCHED
`
`lntei.
`
`anal Application No
`
`
`
`PCT/BE 95/00033
`
`Minimum documentation searched (classification system followed by classification symbols)
`IPC 6
`G06T
`
`Documentation searched other than minimum documentation to the extent that such documents are included in the fields searched
`
`
`
`Electronic data‘ base consulted during the international search (name of data base and, where practical, search terms used)
`
`C. DOCUMENTS CONSIDERED TO BE RELEVANT
`
`_
`
`Category ‘
`
`Citation of document, with indication, where appropriate, of the relevant passages
`
`Relevant to claim No.
`
`AUSTRALASIAN PHYSICAL & ENGINEERING
`
`1-13
`
`SCIENCES IN MEDICINE,
`vol. 16, no. 2, June 1993 AUSTRALIA,
`pages 79-85,
`‘INTEGRATION OF 3-D MEDICAL
`BARKER E.A.
`IMAGING AND RAPID PROTOTYPING TO CREATE
`STEREOLITOGRAPHIC MODELS‘-
`see the whole document
`
`EP-A-0 535 984 (SPECTRA GROUP) 7 Aprii
`1993
`
`see the whole document
`
`1,2,5
`
`D Further documents are listed in the continuation of box C.
`° Special categories of cited documents :
`
`“A” document defining the general state of the art which is not
`considered to be of particular relevance
`‘E’ earlier document but published on or after the international
`filing date
`"I," document which may throw doubts on priority claim(s) or
`which is cited to establish the publication date of another
`citation or other special reason (as specified)
`'0' document referring to an oral disclosure, use, exhibition or
`other means
`‘P’ document published prior to the international filing date but
`later than the priority date claimed
`
`E Patent family members are listed in annex.
`
`"I" later document published after the international filing date
`or priority date and not in conflict with the application but
`cited to understand the principle or theory underlying the
`invention
`'
`‘X’ document of particular relevance; the claimed invention
`cannot be considered novel or cannot be considered to
`involve an inventive step when the document is taken alone
`"Y' document of particular relevance; the claimed invention
`cannot be considered to involve an inventive step when the
`document is combined with one or more other such docu-
`ments, such combination being obvious to a person skilled
`in the art.
`'82.‘ document member of the same patent family
`
`Date of the actual completion of the international search
`
`Date of mailing of the international search report
`
`Burgaud, C
`
`29 June 1995
`
`Name and mailing address of the ISA
`European Patent Office