RU2774257C1 - Method for preoperative planning in hip arthroplasty - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to medicine, namely to radiation diagnostics and traumatology, and can be used in preparation for hip arthroplasty. Plain radiography of the patient's pelvis is performed in direct projection, radiography of the affected joint in direct projection with a marker located in the region of the greater trochanter of the femur and designed to assess the projection increase in radiographs. On the obtained radiographs impose templates of the components of the endoprosthesis, characterized in that the radiography of the pelvis in direct projection is performed in the position of the patient lying on the x-ray table. The patient's pelvis is immovably fixed with the help of device clamps in accordance with figure 1 presented in the application materials, which abut from above against the anterior superior iliac bones so that the iliac spines are located at the same distance from the X-ray table. The wings of the iliac bones are fixed with the help of device clamps resting against them in such a way that the axis passing through the anterior superior iliac spines is perpendicular to the long side of the operating table. The feet are fixed by the device's stop holders, which have the possibility of simultaneous rotation at a given angular velocity around the axes parallel to the long side of the X-ray table and passing through the lower points of the feet in the position of maximum external rotation of the feet so that the axes of the femurs are parallel to each other. Simultaneous rotation of both feet inward to the position of the maximum possible internal rotation is carried out, simultaneously with the rotation of the feet and, accordingly, the femurs, fluoroscopy of the pelvis is performed. From the series of radiographs obtained by fluoroscopy, a radiograph is selected on which the length of the femoral neck is maximum and, accordingly, on which preoperative planning is carried out.

EFFECT: method provides an increase in the accuracy of preoperative planning by fixing the patient's pelvis with the help of device clamps in accordance with figure 1, presented in the application materials.

1 cl, 2 dwg, 1 ex

Description

SUBSTANCE: invention relates to medicine, namely to radiation diagnostics and traumatology, and can be used in preparation for hip arthroplasty.

Currently, in preparation for joint replacement surgery, preoperative planning is carried out.

The following methods of preoperative planning are known.

The method described by Alexander Huppertz, Sebastian Radmer, Patrick Asbach, Ralf Juran et al. Computed tomography for preoperative planning in minimal-invasive total hip arthroplasty: Radiation exposure and cost analysis // European Journal of Radiology. -2011. -N78. - P. 406-413, doi: 10.1016/j.ejrad.2009.11.024. The method consists in performing computed tomography of the pelvis and femur. Then the resulting series of images are loaded into the 3D-Hip Plan ® program (Symbios, Switzerland), in which three-dimensional models of the pelvic and femoral bones are built. Next, templates of endoprosthesis components are used, made in the form of three-dimensional models, which are appropriately applied to the obtained models of the pelvic and femoral bones. The necessary measurements are also carried out on images from a series of tomograms.

The disadvantages of this method are the need to perform computed tomography, which is accompanied by a significant radiation exposure to the patient, as well as the increased duration of the planning itself, associated with the need to process three-dimensional images.

A known method of preoperative planning, the patent of the Republic of Kazakhstan for the invention No. A4 (11) 24497 dated 15.09.2011, "Method for determining the size of the implantable acetabular component of cementless fixation during preoperative planning of primary total hip arthroplasty." The method consists in determining the size of the cup of the endoprosthesis, based on the calculation by the formula: PRVC=PO+1/3 (RO), where:

PRVC is the estimated size of the acetabular component (mm), RO is the usual European size of the patient's shoes in 2/3 cm increments. Based on calculations using this formula, a table was compiled of the correspondence of the patient's shoe size to the expected size of the acetabular component of the hip joint endoprosthesis.

The disadvantage of this method is that it allows you to evaluate only the size of the acetabular component of the endoprosthesis and does not allow you to evaluate a number of parameters necessary during the operation, such as offset, limb length, depth of installation of the stem, cup.

A known method of preoperative planning, RF patent for invention No. 2651056, which is as follows. An axial load is created in the horizontal position of the patient using a device for functional radiology of the feet, containing a platform for support, fixed to the vest and belt of the subject with belts equipped with a dynamometer. A scan is performed from the body of the Thl2 vertebra to the base of the calcaneal bones in the patient's supine position simultaneously in the frontal and sagittal planes. Carry out mechanical and anatomical axes of the lower extremities. The angle formed by the intersection of the line passing through the anterior-superior spine of the wing of the ilium and the lower pole of the patella, and the line, which is the anatomical axis of the tibia, is determined. Determine in the sagittal projection the angle of the pelvis. Analyze scans, print them in true scale. Produce the positioning of the components of the endoprosthesis using fitting stencils and determine the levels of resection.

The disadvantage of this method is its lack of accuracy in patients with severe contractures or ankylosis in the area of the operated joint. The presence of joint contracture, in particular, the restriction of rotational movements in the joint, leads to the impossibility of correct positioning of the patient when performing x-rays. Thus, when performing radiography, the patient's femurs can be located with different rotation in the hip joints, which leads to errors in the calculations on radiographs.

The closest of the known methods of preoperative planning for hip arthroplasty is the method described in the Guide to hip arthroplasty / ed. P.M. Tikhilova, V.M. Shapovalov. - St. Petersburg: RNIITO im. P.P. Vredena, 2008. - p. 184-186), which involves performing a survey radiography of the pelvis with the capture of both hip joints, radiography of the affected joint in direct and lateral projections with a known magnification. Templates of the components of the endoprosthesis are applied to the radiographs, the necessary angles and distances are measured.

The disadvantage of this method is its lack of accuracy in patients with severe contractures or ankylosis in the area of the operated joint, as well as in the presence of spinal deformities. The presence of joint contracture, in particular, the restriction of rotational movements in the joint, leads to the impossibility of correct positioning of the patient when performing x-rays. Thus, when performing radiography, the patient's femurs can be located with different rotation in the hip joints, which leads to errors in the calculations on radiographs. Curvature of the spine leads to incorrect positioning of the patient's pelvis during radiography, which can also lead to errors in calculations on radiographs.

The objective of the invention is to improve the accuracy of preoperative planning of hip arthroplasty.

To solve the problem in the method of preoperative planning for hip arthroplasty, which consists in performing a survey radiography of the patient's pelvis in direct projection, radiography of the affected joint in direct projection with a marker located in the region of the greater trochanter of the femur and intended for assessing the projection magnification of radiographs. Templates of endoprosthesis components are applied to the obtained radiographs. Additionally, X-ray of the pelvis in frontal projection is performed in the position of the patient lying on the X-ray table, the patient's pelvis is immovably fixed with the device clamps, which abut from above against the anterior superior iliac spines so that the iliac bones are located at the same distance from the X-ray table. The wings of the iliac bones are also fixed with the help of device clamps resting against them in such a way that the axis passing through the anterior superior iliac spines is perpendicular to the long side of the operating table. The feet are fixed by the device's stop holders, which have the possibility of simultaneous rotation at a given angular velocity around the axes parallel to the long side of the X-ray table and passing through the lower points of the feet in the position of maximum external rotation of the feet so that the axes of the femurs are parallel to each other. Simultaneous rotation of both feet inward to the position of the maximum possible internal rotation is carried out, simultaneously with the rotation of the feet and, accordingly, the femurs, fluoroscopy of the pelvis is performed. From the series of radiographs obtained during fluoroscopy, the radiograph is selected, on which the length of the femoral neck is maximum and, accordingly, on which preoperative planning is carried out.

When studying other known methods in this field of medicine, this set of features that distinguishes the invention from the prototype was not identified.

In FIG. 1 shows a diagram of a device for implementing the proposed method, Fig. 2 - scheme of fluoroscopy and the position of the patient's feet during the study (A, B, C - the position of the feet, femurs, projections of the femurs on the x-ray cassette during internal rotation of the limbs).

Figure 1 adopted the following designations:

1 - x-ray table;

2 - X-ray table guide;

3 - retainer of the wings of the ilium;

4 - fixator of the anterior upper iliac spines;

5 - stop holder;

6 - hinge;

In figure 2, the following designations are adopted:

7 - pelvic bone;

8 - femur;

9 - axis of the neck of the femur;

10 - transcondylar axis;

11 - X-ray receiver (digital X-ray cassette);

O - anatomical axis of the femur;

ab - femoral offset;

cd - projection of the femoral offset on the x-ray cassette.

The proposed method of preoperative planning for hip arthroplasty is as follows.

Plain radiography of the patient's pelvis 7 is performed in direct projection, radiography of the affected joint in direct projection with a marker located in the region of the greater trochanter of the femur 8 and intended for assessing the projection increase in radiographs. X-ray of the pelvis 7 in frontal projection is performed with the patient lying on the X-ray table 1. The patient's pelvis 7 is fixedly fixed with the help of clamps 4, which rest from above on the anterior superior iliac spines so that they are located at the same distance from the X-ray table 1, and also the wings of the iliac bones are fixed with the help of clamps 3 resting against them in such a way that the axis passing through the anterior superior iliac spines is perpendicular to the long side of the operating table 1. X-ray table 1 and passing through the lower points of the feet in the position of maximum external rotation of the feet so that the axes of the femurs 8 are parallel to each other. Simultaneous rotation of both feet inward to the position of the maximum possible internal rotation is carried out, simultaneously with the rotation of the feet and, accordingly, the femurs 8, fluoroscopy of the pelvis 7 is carried out. respectively, on which preoperative planning is carried out. To do this, templates of the components of the endoprosthesis are applied to the obtained radiographs, and the required angles and distances are also measured.

In most cases, the femoral neck 8 is deviated anteriorly by 10-15 degrees relative to the transcondylar axis 10, the so-called antetorsion position (Zagorodniy N.V. Hip replacement. Fundamentals and practice: a guide. - M .: GEOTAR-Media, 2012. - p. 21). Standard radiography of the pelvis 7 is performed in a position in which the patient's feet are slightly rotated inwards (Fig. 2). In this case, the location of the projection of the neck of the femur 8, respectively, the offset ab on the x-ray cassette 11 cd corresponds to its maximum value.

If the neck is deflected posteriorly from the transcondylar axis 10 (i.e., in the retroversion position), when the feet are rotated from the outermost position inward, the distance cd will decrease. Thus, when taking a standard view exposure, the offset ab will not be correctly estimated.

X-ray examination (in fluoroscopy mode) to reduce radiation exposure to the patient, it is advisable to perform within 1-2 seconds, i.e. the period of time required to rotate the feet, and, accordingly, the femurs 8 from the outermost position to the innermost position. This helps to reduce radiation exposure to the patient. The data can be presented in a personal computer in the form of a series of images or in the form of a so-called "cinema". In the future, the projection offset is estimated on the images, i.e. distance cd, fig. 2.

The device explaining the essence of the proposed method consists of retainers of the wings of the ilium 3 and the anterior superior iliac spines 4. They can be fixed on the guide 2 of the X-ray table 1. The device also includes stop holders 5 connected to the hinge 6. The device has the ability to rotate the stop holder 5 around the hinge axes 6. The hinge axes 6 are parallel to the long side of the x-ray table.

The components of the device that implements the proposed method can be implemented as follows.

As the x-ray machine, a digital x-ray machine capable of performing fluoroscopy can be used.

As retainers of the wings of the iliac bones 3 and the anterior superior iliac spines 4 can be used typical retainers included in the orthopedic operating table. Also they can be made of medical steel.

As the stop holders 5, the stop holders that are part of the orthopedic operating table can be used. For synchronous rotation of the supporters 5 around the hinge axis 6, they can be connected to two electric actuators, for example HY01-12-150 (China). The actuators can be controlled by the surgeon via a radio channel.

Thus, the implementation of the proposed method is beyond doubt, since the device for its implementation uses standard medical devices and materials.

The device that implements the proposed method operates as follows.

X-ray of the pelvis 7 and the affected joint in direct projection is performed with the patient lying on the X-ray table 1. To do this, the patient's pelvis 7 is fixed on the X-ray table 1 using clamps 4, which abut from above against the anterior superior iliac spines so that they are located on the same distance from the X-ray table 1, and also fix the wings of the iliac bones with the help of clamps 3 resting against them, so that the axis passing through the anterior superior iliac spines is perpendicular to the long side of the operating table 1.

The feet are fixed by the foot holders 5, which have the possibility of simultaneous rotation with a given angular velocity around the axes parallel to the long side of the X-ray table 1 and passing through the lower points of the feet, in the position of maximum external rotation of the feet so that the axes of the femurs 8 are parallel to each other. Then, both feet are simultaneously rotated inwards to the position of the maximum possible internal rotation, simultaneously with the rotation of the feet and, accordingly, the femurs, fluoroscopy of the pelvis 7 is performed. The rotation is possible by controlling the actuators via radio communication.

Next, from the series of radiographs obtained by fluoroscopy, a radiograph is selected on which the length of the femoral neck 8 is maximum and, accordingly, on which preoperative planning is carried out. To do this, templates of the components of the endoprosthesis are applied to the obtained radiographs, and the required angles and distances are also measured.

An example of using the proposed method.

To test the proposed method was performed preoperative planning of the patient A., 65 years old with a diagnosis of Right-sided coxarthrosis 3 tbsp. The patient was admitted to surgery with radiographs taken at the outpatient stage. In connection with a pronounced contracture in the right hip joint, radiographs showed an incorrect position of the pelvic bone, as well as various rotations of the femurs. To perform correct planning, the patient underwent radiography in accordance with the proposed method. Due to a pronounced limitation of movements in the affected joint (flexion-adductor contracture) and, accordingly, the lack of the possibility of rotation in the hip joint, the offset was assessed during planning using radiographs on the healthy side.

Preoperative planning, performed in accordance with the proposed method, made it possible to accurately assess the dimensions of the endoprosthesis components installed during the operation and their position.

Planning according to radiographs performed at the outpatient stage contained errors in determining the size of the head, the femoral component of the endoprosthesis, offset and limb length.

Thus, the presence of contractures and curvature of the spine in patients does not always allow making the correct projections when performing radiography due to the presence of pain in patients. Anatomical features of the femur structure, such as the position of the femoral neck in retroversion, also lead to incorrect radiographs.

Incorrectly performed radiographs lead to errors in the calculations performed by surgeons in preparation for surgery.

EFFECT: increased accuracy of preoperative planning in hip arthroplasty.

Claims (1)

A method for preoperative planning in hip arthroplasty, which consists in performing a survey radiography of the patient's pelvis in direct projection, radiography of the affected joint in direct projection with a marker located in the region of the greater trochanter of the femur and intended for assessing the projection increase in radiographs, superimposed on the obtained radiographs templates of endoprosthesis components, characterized in that X-ray of the pelvis in direct projection is performed in the position of the patient lying on the X-ray table, the patient's pelvis is immovably fixed using device clamps in accordance with figure 1 presented in the application materials, which abut from above against the anterior superior iliac spines in such a way so that the iliac bones are located at the same distance from the X-ray table, and also fix the wings of the iliac bones with the help of device clamps resting against them in such a way that the axis passing through the anterior the upper iliac spines were located perpendicular to the long side of the operating table, the feet are fixed by the device’s stop holders, which can simultaneously rotate at a given angular velocity around axes parallel to the long side of the X-ray table and passing through the lower points of the feet in the position of maximum external rotation of the feet in such a way that the axes of the femoral bones were located parallel to each other, both feet are simultaneously rotated inwards to the position of the maximum possible internal rotation, simultaneously with the rotation of the feet and, accordingly, the femurs, fluoroscopy of the pelvis is performed, from the series of radiographs obtained during fluoroscopy, a radiograph is selected on which the length of the femoral neck is maximum and, accordingly, on which preoperative planning is carried out.

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