CN102551892A - Positioning method for craniomaxillofacial surgery - Google Patents

Abstract

The invention discloses a positioning method for a craniomaxillofacial surgery. The positioning method comprises the following steps of: first, producing an occlusal splint referring tracer according to a plaster model of dentition of a patient; secondly, fixing an occlusal splint in an oral cavity of the patient, performing CT (Computed Tomography) scanning on the patient to obtain CT scanning image data, and segmenting and reconstructing the CT scanning image data through CT image reconstruction software to obtain a triangular mesh model of soft and hard craniomaxillofacial tissues of the patient and the occlusal splint referring tracer; and thirdly, arranging a standard fixing reference frame at the head of the patient, reading a transformation matrix M2 of the occlusal splint referring tracer in a three-dimensional coordinate system of the standard fixing reference frame, solving a transformation matrix M of the standard fixing reference frame in the three-dimensional coordinate system of the head, solving a transformation matrix Mf of a light-reflecting ball array of a tool in the three-dimensional coordinate system of the head, tracing and navigating the light-reflecting ball array of the tool relative to the three-dimensional coordinate system of the head in real time, and positioning the light-reflecting ball array of the tool.

Description

A kind of localization method that is used for the craniomaxillofacial surgery operation

Technical field

The present invention relates to a kind of localization method that is used for the craniomaxillofacial surgery operation.

Background technology

In the conventional surgical therapeutic process, clinical examination and the image data of operative doctor before according to patient's art formulated surgical planning, in art, can only rely on the experience and the operation skill of operative doctor carry out surgical planning.This mode is relatively poor to the skill requirement height and the accuracy of operative doctor, is difficult to accurately be decided to be concrete operation technique position in the art.Along with the development of computer-aided design and computer surgery analogue technique, the requirement that reaches the operation degree of accuracy improves gradually, and the navigation surgical technic has obtained development at full speed and has been widely used in the surgery every field.The surgical navigation technology can convert the pre-operative surgical plan in art operation reality more exactly, thereby instructs operative doctor to according to the preceding planning execution operation technique of art.Navigation system commonly used has: the Brainlab system of the Stryker navigation system of the U.S., Germany etc.In the surgical navigation technology a crucial step be exactly soft or hard tissue that patient in the art is actual with art before in the works patient's CT scan image carry out registration, make both synchronous unanimities in operation process.Thereby can confirm the relative position of operating theater instruments, concrete operations position etc. and patient's entity, improve operation accuracy and safety.

Surgical navigation system registration mode commonly used has a registration and surface adjustment dual mode: the some registration is meant through corresponding identification point in structural some identification point of the soft or hard of patient's entity and the patient's virtual image being passed through the related one by one registration of navigation probe; Surface adjustment is meant to be discerned the structural a certain surface of the soft or hard of patient's entity through the navigation probe, navigation system can be automatically with patient's virtual image in the face that matches mate related.But these two kinds of methods all have complex operation in the art, and the registration time is long, and registration accuracy is not good enough and the registration identification point is discerned defectives such as difficulty.Particularly in cranium jaw face field, anatomical structure is complicated, and the operation technique space is limited, and these have just more increased the difficulty of navigation registration.Some navigation system needs to be implanted into the navigator fix nail at patient's body before the art in order to improve registration accuracy, has increased the wound to the patient.

Summary of the invention

Technical problem to be solved by this invention provides a kind of operating localization method of head face amount that is used for; This method has remedied the deficiency of navigator fix registration mode in the existing surgical operation; Make whole navigator fix process more simply, more easy-to-use, more accurate; Before this method has been avoided will performing the operation in the conventional navigation simultaneously in image and the art entity carry out this process of real-time registration; But the method for employing space transformation matrix is carried out the real-time tracing navigation to operating theater instruments and jawbone bone piece, makes whole process quick and precisely.

For solving the problems of the technologies described above, the invention provides a kind of localization method that is used for the craniomaxillofacial surgery operation, may further comprise the steps:

Step 1 according to the model of patient's denture Gypsum Fibrosum, is produced mouth guard with reference to tracer, and this mouth guard is formed by the mouth guard that is complementary with denture with as the witch ball array that tracer uses with reference to tracer;

Step 2; Mouth guard is fixed in patient's the oral cavity; The patient is carried out CT scan; Obtain the CT scan view data, the CT scan view data that obtains is carried out view data through CT image reconstruction software cut apart and reconstruction, obtain facial soft or hard tissue of patient's cranium jaw and mouth guard triangular facet grid model with reference to tracer; Adopt the sphere approximating method to obtain the geometry of mouth guard, and set up mouth guard with reference to the spatial alternation matrix M of tracer in the head three-dimensional system of coordinate with reference to witch ball array on the tracer ₁

Step 3 is laid the fixed standard frame of reference at patient's head, reads mouth guard with reference to the transform matrix M of tracer in the three-dimensional system of coordinate of fixed standard frame of reference through navigation position instrument ₂Find the solution the transform matrix M of fixed standard frame of reference in the head three-dimensional system of coordinate; Then remove the mouth guard tracer, through read arbitrary instrument witch ball array with respect to the transform matrix M of fixed standard frame of reference ', find the solution the transform matrix M of instrument witch ball array in the head three-dimensional system of coordinate _f, according to matrix M _f, carry out the real-time tracing navigation of the relative head three-dimensional system of coordinate of instrument witch ball array, the instrument witch ball array of representing operation tool to use is positioned, thereby realize the real-time tracking navigator fix that craniomaxillofacial surgery is performed the operation.

In the step 2; Described sphere approximating method; Be meant CT scan data, rebuild the triangular facet grid model of each ball in the array, the triangular facet grid model of single ball is split according to instrument witch ball array on the mouth guard; Use method of least square, iterative goes out to ask the sphere centre coordinate of each sphere and the radius of sphere.

Can interferential some cranium jaw operation on face for mouth guard with reference to tracer; In art, can directly use navigator fix to read arbitrary instrument witch ball array, find the solution the transformation matrix T of this instrument witch ball array in the head coordinate system with respect to the transformation matrix T of mouth guard with reference to tracer _f, according to matrix T _f, realize of the real-time tracing navigation of this instrument witch ball array with respect to the head coordinate system, this instrument is accurately located, realize the real-time tracking navigation and the location of craniomaxillofacial surgery operation.

For orthognatic surgery, set up the spatial alternation matrix M of mouth guard frame of reference in the head coordinate system ₁After, read the transform matrix M of mouth guard frame of reference in fixed standard frame of reference coordinate system through navigation position instrument in the art ₂, find the solution transform matrix M ₂Inverse matrix N, according to matrix M ₁* N=W, realize mouth guard with reference to tracer with respect to real-time tracing with reference to the head coordinate system, thereby in art direct location tracking jawbone bone block space position, realize the precision navigation of orthognatic surgery is instructed.

Matrixing step in this localization method can be used as the application in the orthopaedic surgical operations navigation.

The present invention has following useful technique effect:

(1) mouth guard is directly fixed in patient's the oral cavity, fixed-site and unique, favorable repeatability does not have any wound to the patient;

(2) through confirming the locus coordinate of mouth guard with reference to tracer; Locus through matrix operations position patient entity; Thereby the three-dimensional surface grid model that CT before patient's entity and the art is rebuild matees, and all processes is positioned by geometric operation, has higher accuracy;

(3) avoided error in the conventional registration process, need not index point is carried out loaded down with trivial details registration process one by one, adopted the method for matrixing, all location and computing are accomplished by computer program automatically, and whole position fixing process only needs the several seconds.

Description of drawings

Fig. 1 is the sketch map of iterative algorithm in the embodiment of the invention;

Fig. 2 is for setting up the sphere centre coordinate sketch map of mouth guard three-dimensional system of coordinate in the embodiment of the invention;

Fig. 3 is a transform matrix M in the embodiment of the invention ₂The conversion sketch map;

Fig. 4 is the conversion sketch map of transform matrix M in the embodiment of the invention;

Fig. 5 is a transform matrix M in the embodiment of the invention _fThe conversion sketch map;

Fig. 6 is transformation matrix T in the embodiment of the invention _fThe conversion sketch map;

Fig. 7 is the matrix sketch map of orthognatic surgery in the embodiment of the invention.

The specific embodiment

Below in conjunction with accompanying drawing and specific embodiment the present invention is done further explain.

Embodiment:

A kind of localization method that is used for the craniomaxillofacial surgery operation, its step is following:

Step 1 according to the model of patient's denture Gypsum Fibrosum, is produced mouth guard with reference to tracer, and this mouth guard is formed by the mouth guard that is complementary with denture with as the witch ball array that tracer uses with reference to tracer, and unique its in position has repeatability preferably;

Step 2; Mouth guard is fixed in patient's the oral cavity; The patient is carried out CT scan; Obtain the CT scan view data, the CT scan view data that obtains is carried out view data through CT image reconstruction software cut apart and reconstruction, obtain facial soft or hard tissue of patient's cranium jaw and mouth guard triangular facet grid model with reference to tracer; Adopt the sphere approximating method to obtain the geometry of mouth guard, and set up mouth guard with reference to the spatial alternation matrix M of tracer in the head three-dimensional system of coordinate with reference to witch ball array on the tracer ₁

Sphere approximating method in the step 2: this method is according to the CT scan data of witch ball array on the mouth guard; Rebuild the triangular facet grid model of each ball in the array; The triangular facet grid model of single ball is split; Use method of least square, iterative goes out to ask the sphere centre coordinate of each sphere and the radius of sphere.

Specific algorithm is following:

For the single sphere that splits, row are got the summit P of its whole triangular facet grids _i, (i=1,2 ..., n); Since the reconstruction model noisy, P _iCan not all be distributed on the sphere, establish and wait that asking the sphere centre coordinate of sphere is (x _c, y _c, z _c, P), spherical radius r ²

The method of least square algorithm steps is:

1. confirm (x _c, y _c, z _c, initial value P)

$f(x_c,y_c,z_c,P)=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{[{(P_{\mathrm{ix}}-x_c)}^1+{(P_{\mathrm{iy}}-y_c)}^2+{(P_{\mathrm{iz}}-z_c)}^2-r^2]}^2$

In order to make f (x _c, y _c, z _c, P) minimum, $\frac{\∂f}{{\∂x}_c}=0,$ $\frac{\∂f}{\∂y_c}=0,$ $\frac{\∂f}{\∂z_c}=0.$ $\frac{\∂f}{\∂r}=0.$

The implication of f is P _i, (i=1,2 ..., n) discrete point range is to target spherical distance biquadratic. and f=0 in theory, but owing to the existence of noise, f can not be 0.

According to $\frac{\&PartialD;f}{\&PartialD;x_c}=\frac{\&PartialD;f}{\&PartialD;y_c}=\frac{\&PartialD;f}{\&PartialD;z_c}=\frac{\&PartialD;f}{\&PartialD;r}=0,$ If $d=r^2-x_c^2-y_c^2-{\mathrm{<figure-callout\; id="2"\; label="z\; c"\; filenames="HSA00000660145700012.png"\; state="\{\{state\}\}">z</figure-callout>}}_c^{},$ We obtain:

$\left[\begin{array}{cccc}2\underset{i=1}{\overset{\mathrm{<figure-callout\; id="2"\; label="n\; P\; ix"\; filenames="HSA00000660145700012.png"\; state="\{\{state\}\}">n</figure-callout>}}{\mathrm{\&Sigma;}}}{P}_{\mathrm{ix}}^{}{}_2^{}& 2\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{P}_{\mathrm{<figure-callout\; id="2"\; label="ix\; P\; iy"\; filenames="HSA00000660145700012.png"\; state="\{\{state\}\}">ix</figure-callout>}}{P}_{\mathrm{iy}}{}_{}& 2\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{P}_{\mathrm{ix}}{P}_{\mathrm{iz}}& \underset{i=1}{\overset{\mathrm{<figure-callout\; id="2"\; label="n\; P\; ix"\; filenames="HSA00000660145700012.png"\; state="\{\{state\}\}">n</figure-callout>}}{\mathrm{\&Sigma;}}}{P}_{\mathrm{ix}}{}_{}\\ 2\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{P}_{\mathrm{<figure-callout\; id="2"\; label="ix\; P\; iy"\; filenames="HSA00000660145700012.png"\; state="\{\{state\}\}">ix</figure-callout>}}{P}_{\mathrm{iy}}{}_{}& 2\underset{i=1}{\overset{\mathrm{<figure-callout\; id="2"\; label="n\; P\; iy"\; filenames="HSA00000660145700012.png"\; state="\{\{state\}\}">n</figure-callout>}}{\mathrm{\&Sigma;}}}{P}_{\mathrm{iy}}^{}{}_2^{}& 2\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{P}_{\mathrm{iy}}{P}_{\mathrm{iz}}& \underset{i=1}{\overset{\mathrm{<figure-callout\; id="2"\; label="n\; P\; iy"\; filenames="HSA00000660145700012.png"\; state="\{\{state\}\}">n</figure-callout>}}{\mathrm{\&Sigma;}}}{P}_{\mathrm{iy}}{}_{}\\ 2\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{P}_{\mathrm{ix}}{P}_{\mathrm{iz}}& 2\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{P}_{\mathrm{iy}}{P}_{\mathrm{iz}}& 2\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{P}_{\mathrm{iz}}^2& \underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{P}_{\mathrm{iz}}\\ 2\underset{i=1}{\overset{\mathrm{<figure-callout\; id="2"\; label="n\; P\; ix"\; filenames="HSA00000660145700012.png"\; state="\{\{state\}\}">n</figure-callout>}}{\mathrm{\&Sigma;}}}{P}_{\mathrm{ix}}{}_{}& 2\underset{i=1}{\overset{\mathrm{<figure-callout\; id="2"\; label="n\; P\; iy"\; filenames="HSA00000660145700012.png"\; state="\{\{state\}\}">n</figure-callout>}}{\mathrm{\&Sigma;}}}{P}_{\mathrm{iy}}{}_{}& 2\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{P}_{\mathrm{iz}}& n\end{array}\right]\left[\begin{array}{c}{x}_c\\ y_c\\ z_c\\ r\end{array}\right]=\left[\begin{array}{c}f1\\ f2\\ f3\\ f4\end{array}\right]$

If ${{\mathrm{<figure-callout\; id="2"\; label="P\; Ix"\; filenames="HSA00000660145700012.png"\; state="\{\{state\}\}">P</figure-callout>}}_{\mathrm{Ix}}}^2+{{\mathrm{<figure-callout\; id="2"\; label="P\; Iy"\; filenames="HSA00000660145700012.png"\; state="\{\{state\}\}">P</figure-callout>}}_{\mathrm{Iy}}}^2+{{\mathrm{<figure-callout\; id="2"\; label="P\; Iz"\; filenames="HSA00000660145700012.png"\; state="\{\{state\}\}">P</figure-callout>}}_{\mathrm{Iz}}}^2={{\mathrm{<figure-callout\; id="2"\; label="P\; Ixyz"\; filenames="HSA00000660145700012.png"\; state="\{\{state\}\}">P</figure-callout>}}_{\mathrm{Ixyz}}}^2$

Wherein $f_1=\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{P}_{\mathrm{Ix}}{P_{\mathrm{Ixyz}}}^2$

${\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="HSA00000660145700012.png"\; state="\{\{state\}\}">f</figure-callout>}}_2=\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{P}_{\mathrm{<figure-callout\; id="2"\; label="iy\; P\; ixyz"\; filenames="HSA00000660145700012.png"\; state="\{\{state\}\}">iy</figure-callout>}}{P_{\mathrm{ixyz}}}^{}{{}_{}}^2$

$f_3=\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{P}_{\mathrm{iz}}{{\mathrm{<figure-callout\; id="2"\; label="P\; ixyz"\; filenames="HSA00000660145700012.png"\; state="\{\{state\}\}">P</figure-callout>}}_{\mathrm{ixyz}}}^2$

$f_4=\underset{i=1}{\overset{\mathrm{<figure-callout\; id="2"\; label="n\; P\; ixyz"\; filenames="HSA00000660145700012.png"\; state="\{\{state\}\}">n</figure-callout>}}{\mathrm{\&Sigma;}}}{P_{\mathrm{ixyz}}}^{}{{}_{}}^2$

$r=\sqrt{d-x_c^2-y_c^2-{\mathrm{<figure-callout\; id="2"\; label="z\; c"\; filenames="HSA00000660145700012.png"\; state="\{\{state\}\}">z</figure-callout>}}_c^{}}$

Thereby solve x _c, y _c, z _c, the initial value of r, beginning iterative process.

2. as shown in Figure 1, the iterative algorithm:

P ' _iParametric expressions is:

P _ix′＝z _c+rcosu _isinv _i

P _iy′＝y _c+rsinu _isinv _i

P _iz′＝z _c+rcosv _i

The structure object function:

$F(x_c,y_c,z_c,r,u_1,v_1,{\mathrm{<figure-callout\; id="2"\; label="u"\; filenames="HSA00000660145700012.png"\; state="\{\{state\}\}">u</figure-callout>}}_2,{\mathrm{<figure-callout\; id="2"\; label="v"\; filenames="HSA00000660145700012.png"\; state="\{\{state\}\}">v</figure-callout>}}_2,...,u_n,v_n)$

$=\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}[{(P_{\mathrm{ix}}-P_{\mathrm{ix}}^{\&prime;})}^2+{(P_{\mathrm{iy}}-P_{\mathrm{iy}}^{\&prime;})}^2+{(P_{\mathrm{iz}}-P_{\mathrm{iz}}^{\&prime;})}^2]$

$=\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}[{(P_{\mathrm{ix}}-x_c-r\cos u_i\sin v_i)}^2+{(P_{\mathrm{iy}}-y_c-r{\sin u}_i\sin v_i)}^2+{(P_{\mathrm{iz}}-z-r\cos v_i)}^2]$

$x_{\mathrm{\&epsiv;}}=\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{P}_{\mathrm{ix}};$ $y_{\mathrm{\&epsiv;}}=\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{P}_{\mathrm{iy}};$ $z_{\mathrm{\&epsiv;}}=\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{P}_{\mathrm{iz}};$

$r_{\mathrm{\&epsiv;}}=\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}(P_{\mathrm{ix}}\cos u_i\sin v_i+P_{\mathrm{iy}}\sin u_i\sin v_i+z_c\cos v_i)$

For making F minimum, have:

$\frac{\&PartialD;F}{\&PartialD;x_c}=0,$ $\frac{\&PartialD;F}{\&PartialD;y_c}=0,$ $\frac{\&PartialD;F}{\&PartialD;z_c}=0,$ $\frac{\&PartialD;F}{\&PartialD;r}=0$

$\frac{\&PartialD;F}{\&PartialD;u_i}=\frac{\&PartialD;F}{\&PartialD;v_i}=0$

i＝1，2，…，n；u _i

According to $\frac{\&PartialD;F}{\&PartialD;x_c}=\frac{\&PartialD;F}{\&PartialD;y_c}=\frac{\&PartialD;F}{\&PartialD;z_c}=\frac{\&PartialD;F}{\&PartialD;r}=0,$ We obtain:

$\left[\begin{array}{cccc}\mathrm{<figure-callout\; id="0"\; label="n"\; filenames="HSA00000660145700021.png"\; state="\{\{state\}\}">n</figure-callout>}& 0& 0& \underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}\cos u_i\sin v_i\\ 0& \mathrm{<figure-callout\; id="0"\; label="n"\; filenames="HSA00000660145700021.png"\; state="\{\{state\}\}">n</figure-callout>}& 0& \underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}\sin u_i\mathrm{<figure-callout\; id="0"\; label="sin\; v\; i"\; filenames="HSA00000660145700021.png"\; state="\{\{state\}\}">sin</figure-callout>}{v}_i{}_{}\\ 0& 0& n& \underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}\cos v_i\\ \underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}\cos u_i\sin v_i& \underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}\sin u_i\sin v_i& \underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}\cos v_i& n\end{array}\right]\left[\begin{array}{c}{x}_c\\ y_c\\ z_c\\ r\end{array}\right]=\left[\begin{array}{c}{x}_{\mathrm{\&Sigma;}}\\ y_{\mathrm{\&Sigma;}}\\ z_{\mathrm{\&Sigma;}}\\ r_{\mathrm{\&Sigma;}}\end{array}\right]$

$x_{\mathrm{\&epsiv;}}=\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{P}_{\mathrm{ix}};$ $y_{\mathrm{\&epsiv;}}=\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{P}_{\mathrm{iy}};$ $z_{\mathrm{\&epsiv;}}=\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{P}_{\mathrm{iz}};$

$r_{\mathrm{\&epsiv;}}=\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}(P_{\mathrm{ix}}\cos u_i\sin v_i+P_{\mathrm{iy}}\sin u_i\sin v_i+z_c\cos v_i)$

According to

I=1,2 ..., n; Find the solution u _i, v _iProcess be:

1)u _i＝arctan[|(P _iy-y _c)/(P _ix-x _c)|]

2) $v_i=\arctan \left[\right|\frac{(P_{\mathrm{ix}}-x_c)\cos u_i+(P_{\mathrm{iy}}-y_c)\sin v_i}{(P_{\mathrm{iz}}-z_c)}\left|\right].$

Iterative process is:

(1) according to x _c, y _c, z _c, the initial value of r r ⁰, find the solution:

Calculate F ⁰

(2) basis

Find the solution x _c, y ' _c, z ' _c, r ';

(3) order $x_c^{}$ ${}_0^{}=x_c^{\&prime;};$ ${\mathrm{<figure-callout\; id="0"\; label="y\; c"\; filenames="HSA00000660145700021.png"\; state="\{\{state\}\}">y</figure-callout>}}_c^{}=y_c^{\&prime;};$ ${\mathrm{<figure-callout\; id="0"\; label="z\; c"\; filenames="HSA00000660145700021.png"\; state="\{\{state\}\}">z</figure-callout>}}_c^{}=z_c^{\&prime;};$ r ⁰=r ' calculates F ';

(4) repeating step 1,2,3, up to | F '-F ⁰|≤ε, the error of ε for setting is as 0.0001;

Find the solution completion, obtain (x _c, y _c, z _c, r).

In the step 2, set up mouth guard with reference to the spatial alternation matrix M of tracer in the head three-dimensional system of coordinate ₁:

1) as shown in Figure 2, the sphere centre coordinate of establishing 4 spheres is:

A：(x _a，y _a，z _a)

B：(x _b，y _b，z _b)

C：(x _c，y _c，z _c)

D：(x _d，y _d，z _d)

2) the coordinate system x ' y ' z ' of structure instrument witch ball array,

$\stackrel{\&RightArrow;}{\mathrm{AC}}=[(x_c-x_a),(y_c-y_a),(z_c-z_a)]$

$\stackrel{\&RightArrow;}{\mathrm{BD}}=[(x_d-x_b),(y_d-y_b),(z_d-z_b)]$

If $\stackrel{\&RightArrow;}{x^{\&prime;}}=\frac{\stackrel{\&RightArrow;}{\mathrm{AC}}}{\left|\stackrel{\&RightArrow;}{\mathrm{AC}}\right|};$ $\stackrel{\&RightArrow;}{y^{\&prime;}}=\frac{\stackrel{\&RightArrow;}{\mathrm{BD}}}{\left|\stackrel{\&RightArrow;}{\mathrm{BD}}\right|};$ $\stackrel{\&RightArrow;}{z^{\&prime;}}=\stackrel{\&RightArrow;}{x^{\&prime;}}\&times;\stackrel{\&RightArrow;}{y^{\&prime;}}$

X ' y ' z ' coordinate origin is:

$o_x^{\&prime;}=\frac{x_a+x_b+x_c+x_d}{4};$ $o_i^{\&prime;}=\frac{y_a+y_b+y_c+y_a}{4};$ $o_z^{\&prime;}=\frac{z_a+z_b+z_c+z_d}{4}.$

3) establish $\stackrel{\&RightArrow;}{x^{\&prime;}}=(u_1,{\mathrm{<figure-callout\; id="2"\; label="u"\; filenames="HSA00000660145700012.png"\; state="\{\{state\}\}">u</figure-callout>}}_2,u_3);$ $\stackrel{\&RightArrow;}{y^{\&prime;}}=(v_1,{\mathrm{<figure-callout\; id="2"\; label="v"\; filenames="HSA00000660145700012.png"\; state="\{\{state\}\}">v</figure-callout>}}_2,v_3);$ $\stackrel{\&RightArrow;}{z^{\&prime;}}=(w_1,{\mathrm{<figure-callout\; id="2"\; label="w"\; filenames="HSA00000660145700012.png"\; state="\{\{state\}\}">w</figure-callout>}}_2,w_3);$ $\stackrel{\&RightArrow;}{o^{\&prime;}}=(t_1,{\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="HSA00000660145700012.png"\; state="\{\{state\}\}">t</figure-callout>}}_2,t_3),$

The transform matrix M of structure x ' y ' z ' coordinate system and xyz coordinate system ₁:

$M_1=\left[\begin{array}{cccc}{u}_1& v_1& w_1& t_1\\ u_2& v_2& w_2& t_2\\ u_3& v& w_3& t_3\\ 0& 0& 0& 1\end{array}\right]$

Step 3 is laid the fixed standard frame of reference at patient's head, reads mouth guard with reference to the transform matrix M of tracer in the three-dimensional system of coordinate of fixed standard frame of reference through navigation position instrument ₂Find the solution the transform matrix M of fixed standard frame of reference in the head three-dimensional system of coordinate; Then remove the mouth guard tracer, through read arbitrary instrument witch ball array with respect to the transform matrix M of fixed standard frame of reference ', find the solution the transform matrix M of instrument witch ball array in the head three-dimensional system of coordinate _f, according to matrix M _f, carry out the real-time tracing navigation of the relative head three-dimensional system of coordinate of instrument witch ball array, instrument witch ball array is positioned, thereby realize the real-time tracking navigator fix that craniomaxillofacial surgery is performed the operation.

The concrete matrix mapping algorithm of step 3 is:

As shown in Figure 3, establishing coordinate system x ' y ' z ' transformation matrix in the standard frame of reference three-dimensional system of coordinate on being fixed in skull is M ₂

As shown in Figure 4, the transformation matrix of canonical reference frame in three-dimensional system of coordinate xyz that is fixed in skull is M:M=M ₁.M ₂ ^-1

As shown in Figure 5, establishing arbitrary instrument witch ball array is M ' with respect to the transformation matrix of the canonical reference rack coordinate system of being fixed in skull in navigation procedure, and then this instrument witch ball array with respect to the transformation matrix of coordinate system xyz is: M _f=MM; Matrixing is accomplished.

According to matrix M _f, realize this instrument witch ball array (being that instrument is with reference to device) real-time tracing navigation of head three-dimensional system of coordinate (xyz) relatively, instrument is accurately located.

Tracer is a machinery, is made up of 4 witch balls on the Metallic rod of a similar cross and 4 the arm ends; Instrument witch ball array is meant 4 witch balls after CT scan and data are rebuild, and a kind of title of mathematical, the mathematical model aspect that obtains with methods such as sphere matches mentioned above.

In the present embodiment; Can interferential some cranium jaw operation on face for mouth guard with reference to tracer; As shown in Figure 6; In art, can directly use navigator fix to read the transformation matrix T of arbitrary instrument tracer, find the solution the transformation matrix T of instrument tracer in head coordinate system (xyz) with respect to mouth guard _f, according to matrix T _f(T _f=M ₁* T), matrixing is accomplished, and the real-time tracing navigation of the relative head coordinate system of implementation tool tracer (xyz) is accurately located instrument.

In the present embodiment, as shown in Figure 7 for orthognatic surgery, set up the spatial alternation matrix M of mouth guard frame of reference in head coordinate system (xyz) ₁After, read the transform matrix M of mouth guard frame of reference in fixed standard frame of reference coordinate system through navigation position instrument in the art ₂, find the solution transform matrix M ₂Inverse matrix N, according to matrix W (M ₁* N=W), realize mouth guard with reference to the real-time tracing of tracer with respect to reference frame (xyz), thereby in art direct location tracking jawbone bone block space position, realize the precision navigation of orthognatic surgery is instructed.

In the described localization method of present embodiment, the matrixing step can be used as the application in the orthopaedic surgical operations navigation.

Above-listed detailed description is to the specifying of one of the present invention possible embodiments, and this embodiment is not in order to limiting claim of the present invention, and the equivalence that all the present invention of disengaging do is implemented or change, all should be contained in the claim of this case.

Claims (5)

1. a localization method that is used for the craniomaxillofacial surgery operation is characterized in that, may further comprise the steps:

Step 1 according to the model of patient's denture Gypsum Fibrosum, is produced mouth guard with reference to tracer, and this mouth guard is formed by the mouth guard that is complementary with denture with as the witch ball array that tracer uses with reference to tracer;

Step 2; Mouth guard is fixed in patient's the oral cavity; The patient is carried out CT scan; Obtain the CT scan view data, the CT scan view data that obtains is carried out view data through CT image reconstruction software cut apart and reconstruction, obtain facial soft or hard tissue of patient's cranium jaw and mouth guard triangular facet grid model with reference to tracer; Adopt the sphere approximating method to obtain the geometry of mouth guard, and set up mouth guard with reference to the spatial alternation matrix M of tracer in the head three-dimensional system of coordinate with reference to witch ball array on the tracer ₁

Step 3 is laid the fixed standard frame of reference at patient's head, reads mouth guard with reference to the transform matrix M of tracer in the three-dimensional system of coordinate of fixed standard frame of reference through navigation position instrument ₂Find the solution the transform matrix M of fixed standard frame of reference in the head three-dimensional system of coordinate; Then remove the mouth guard tracer, through read arbitrary instrument witch ball array with respect to the transform matrix M of fixed standard frame of reference ', find the solution the transform matrix M of instrument witch ball array in the head three-dimensional system of coordinate _f, according to matrix M _f, carry out the real-time tracing navigation of the relative head three-dimensional system of coordinate of instrument witch ball array, instrument witch ball array is positioned, thereby realize the real-time tracking navigator fix that craniomaxillofacial surgery is performed the operation.

2. a kind of localization method that is used for the craniomaxillofacial surgery operation according to claim 1; It is characterized in that: in the step 2, described sphere approximating method is meant the CT scan data according to witch ball array on the mouth guard; Rebuild the triangular facet grid model of each ball in the array; The triangular facet grid model of single ball is split, use method of least square, iterative goes out to ask the sphere centre coordinate of each sphere and the radius of sphere.

3. a kind of localization method that is used for the craniomaxillofacial surgery operation according to claim 1; It is characterized in that: can interferential some cranium jaw operation on face with reference to tracer for mouth guard; In art, can directly use navigator fix to read arbitrary instrument witch ball array, find the solution the transformation matrix T of this instrument witch ball array in the head coordinate system with respect to the transformation matrix T of mouth guard with reference to tracer _f, according to matrix T _f, realize of the real-time tracing navigation of this instrument witch ball array with respect to the head coordinate system, this instrument is accurately located, realize the real-time tracking navigation and the location of craniomaxillofacial surgery operation.

4. a kind of localization method that is used for the craniomaxillofacial surgery operation according to claim 1 is characterized in that: for orthognatic surgery, set up the spatial alternation matrix M of mouth guard frame of reference in the head coordinate system ₁After, read the transform matrix M of mouth guard frame of reference in fixed standard frame of reference coordinate system through navigation position instrument in the art ₂, find the solution transform matrix M ₂Inverse matrix N, according to matrix M ₁* N=W, realize mouth guard with reference to tracer with respect to real-time tracing with reference to the head coordinate system, thereby in art direct location tracking jawbone bone block space position, realize the precision navigation of orthognatic surgery is instructed.

5. a kind of localization method that is used for the craniomaxillofacial surgery operation according to claim 1 is characterized in that: the matrixing step in this localization method can be used as the application in the orthopaedic surgical operations navigation.

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