RU2839808C1 - Method for multiapex deformities correction of long bones - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention refers to medicine, namely to traumatology and orthopaedics, and can be used for correction of multilevel long bone deformities. Transosseous elements are delivered, and proximal, distal and intermediate supports of an external fixation apparatus are mounted. Osteotomies are performed at the level of each apex of deformation. Orthopaedic hexapod is assembled, in the computer program of which initial X-ray images, parameters of the hexapod and parameters of the required position of the fragments are entered. Axes of the distal and proximal fragments are virtually marked and matched, the correction results are simulated, and the final position of the intermediate fragment is marked. Material template of the intermediate fragment is made, which is used to measure the lengths of each of the distraction regenerates, as well as to calculate the length variations of each of them at the proximal osteotomy levels over the correction period. Greatest regenerate length change is specified, and an optimal number of correction days is determined by dividing the chosen regenerate length change by a planned rate of correction. Calculated number of correction days is entered into a computer program to generate a correction schedule. After the correction is completed, the elastic tie-rods and strata of the hexapod are replaced with fixed hinge joints or with straight threaded rods.

EFFECT: method enables reducing a risk of complications related to an incorrectly specified number of correction days, including a risk of premature consolidation, regenerate rupture and neuropathy, due to a set of techniques of the declared invention.

5 cl, 49 dwg, 1 ex

Description

The invention relates to medicine, namely to traumatology and orthopedics, and can be used in the correction of multi-apex deformities of the long bones of the extremities.

A method for correcting multi-apex deformities of long bones is known, which involves the use of several orthopedic hexapods: one for each apex of the deformity with simultaneous elimination of the deformity at all levels (Naqui, S. Zafar H.; Thiryayi, Wasiq; Foster, Anne; Tselentakis, George; Evans, Martha; Day, John B., 2008).

However, the technique has the following disadvantages:

- significant weight of the metal structure, which aggravates the patient’s discomfort from wearing the AVF;

- the presence of two or more hexapods requires more labor on the part of the doctor, since it is necessary to perform several isolated calculations in a computer program, and when performing a correction, it is necessary to change the length of not 6, but 12 or 18 (with 3 deformation vertices) strata;

- the correction process is complicated by the presence of a nonlinear intermediate fragment, since the use of its anatomical axis is unacceptable. Otherwise, additional correction may be required;

- the implementation of the method requires a large amount of expensive equipment (orthopedic hexapods), which makes the method more costly.

The calculation of the optimal number of days of correction is performed in a computer program separately for each level.

The closest method to the proposed method is the so-called "spring technique" (Patent of the Russian Federation No. 2640999 dated 12.01.18, Solomin L.N., Shchepkina E.A., Pozdeev A.P., Vilensky V.A., Korchagin K.L., Sabirov F.K., Zakharyan E.A., Gadzhiev V.E). The correction is performed simultaneously at the levels of all deformation vertices using only one orthopedic hexapod. The intermediate support is attached to the adjacent ones using springs. The method according to Patent of the Russian Federation No. 2640999 was chosen as a prototype of the claimed invention.

However, the known method has the following disadvantage:

- there is no procedure for determining the optimal number of days of correction in the computer program of the orthopedic hexapod. According to the algorithm for implementing the "spring technique", when performing calculations in the computer program, only the axes of the proximal and distal fragments are used (Patent of the Russian Federation No. 2640999 dated 12.01.18, Solomin L.N., Shchepkina E.A., Pozdeev A.P., Vilensky V.A., Korchagin K.L., Sabirov F.K., Zakharyan E.A., Gadzhiev V.E). When installing SAR 1 on the point of the distal fragment, which is subject to maximum displacement during correction (as required by the methodology of working with the program of the orthopedic hexapod Ortho-SUV), the program estimates the length of the distraction regenerate significantly greater than the actual value. By default, the program algorithm makes one correction calculation in the presence of 2-3 distraction regenerates, and therefore, the program evaluates the change in the length of only one of them, the shape and length of which the program determines based on the axes. As a result, the number of correction days calculated by the program is excessively large, significantly exceeding the correction period when implementing the "traditional" technique (several orthopedic hexapods). In the most modern version of the computer program for orthopedic hexapods, there is no way to calculate the optimal number of correction days when implementing the "spring" technique, which ensures optimal displacement of each of the fragments. In the overwhelming majority of cases, the recommended rate of lengthening of the distraction regenerate is 1 mm per day (Ilizarov G.A. et al., 1985,1995; Shevtsov V.I., 1996; Hasler C. C. et al., 2012; Shevtsov V.I. 2022).

The objective of the claimed invention is to improve the method for correcting multi-apex deformations of long bones, which makes it possible to eliminate the above-mentioned shortcomings and ensure the recommended rate of lengthening of the distraction regenerate.

The technical results of the claimed method are:

- the possibility of calculating the optimal number of days for correction of multi-vertex deformations when implementing the “spring technique” provided that each of the fragments is displaced by a distance of no more than 1 mm per day;

- reducing the risk of complications associated with an incorrectly selected number of days of correction, both excessively large, which can cause premature consolidation, and excessively small, which results in a rupture of the regenerate, neuropathy;

- reduction of economic costs for treatment by reducing the time of correction and the patient’s stay in hospital.

Thus, the orthopedist, performing the calculation according to the claimed invention using the computer program of the orthopedic hexapod when implementing the “spring” technique, ensures a controlled rate of correction, not exceeding the recommended values of 1 mm per day.

The specified technical result of the invention is achieved due to the fact that in the method for correcting multi-apex (multi-level) deformations of long bones, including determining the axes of the proximal, distal and intermediate (intermediate) fragments according to X-ray or CT data and the axes of deformations, planning the levels of osteotomies and the position of the supports of the external fixation apparatus, intraoperative implementation of transosseous elements and installation of supports, performing osteotomy according to preoperative planning and subsequent distraction at the level of each of the axes of deformation, installation of an orthopedic hexapod, measurement of its parameters and X-ray examination, a computer program is used, into which the initial data of the patient, his X-rays, the parameters of the hexapod and the parameters of the required position of the fragments are entered, and the axes of the distal and proximal fragments are designated and combined in the program.

Then, additionally, the initial boundaries and contours of the distal bone fragment are designated with color indicators, the correction results are virtually simulated and the final position of the proximal fragment is marked, the contours of the intermediate fragment are designated and its material template is made, the lengths of each of the distraction regenerates are measured, and the values of the change in the length of each of them at the levels of the proximal osteotomy during the correction period are calculated, the greatest value of the change in the length of the regenerate is selected, the optimal number of days of correction is determined by dividing the selected value of the change in the length of the regenerate by the planned rate of correction, the calculated number of days of correction is entered into the computer program to generate a correction schedule. After that, the optimal terms of deformation correction are calculated and a correction schedule is generated, upon completion of which the orthopedic hexapod and springs are dismantled. After the correction is completed, the elastic tractions and struts of the hexapod are replaced with fixed hinge joints.

The figures depict:

Fig. 1: Preoperative planning for correction of multi-apical femoral deformity.

Fig. 2: Completed installation of the proximal, intermediate and distal modules of the AVF.

Fig. 3: The supports are connected by two-plane hinges; osteotomies are performed at two levels.

Fig.4: Result of distraction, achieving optimal diastasis at both levels.

Fig. 5: The AVF has been reassembled. The two-plane hinges have been replaced with orthopedic hexapod struts and springs.

Fig. 6: Calculation of correction in a computer program, step 1.

Fig. 7: Calculation of correction in a computer program, step 2.

Fig. 8: Calculation of correction in a computer program, step 3.

Fig. 9: Calculation of correction in a computer program, step 4.

Fig. 10: Calculation of correction in a computer program, step 5.

Fig. 11: Calculation of correction in a computer program, step 6.

Fig. 12: Calculation of correction in a computer program, step 7.

Fig. 13: Calculation of correction in a computer program, step 8.

Fig. 14: Positioning the "yellow dots", step 8

Fig. 15: Calculation of correction in a computer program, step 9.

Fig. 16: Calculation of correction in a computer program, step 10.

Fig.17: Using a custom intermediate fragment template. Matching contours.

Fig.18: Using a custom intermediate fragment template. Simulating the final position.

Fig.19: Measurement of the initial length of the proximal regenerate (ILPR), starting point

Fig.20: Measurement of the initial length of the proximal regenerate (ILPR), end point

Fig.21: Measurement of the initial length of the distal regenerate (ILDR), starting point

Fig.22: Measurement of the initial length of the distal regenerate (ILDR), end point

Fig.23: Measurement of the planned length of the proximal regenerate (PLPR), starting point

Fig.24: Measurement of the planned length of the proximal regenerate (PLPR), end point

Fig.25: Measurement of the planned distal regenerate length (PDRL), starting point

Fig.26: Measurement of the planned distal regenerate length (PDRL), end point

Fig. 27. Calculation of correction in a computer program, step 12.

Fig. 28. Correction successfully completed. Before re-editing.

Fig. 29. Correction successfully completed. AVF remounted, orthopedic hexapod struts and springs replaced with biplane hinges.

Fig.30: Patient K., appearance before surgery, front view

Fig.31: Patient K., appearance before surgery, side view

Fig. 32: Patient K., teleradiogram before surgery. Varus deformity is revealed in the frontal plane.

Fig. 33: Patient K., radiograph of the right leg in lateral projection before surgery. There is no deformation in the sagittal plane.

Fig.34: Patient K., preoperative planning, marking osteotomy levels

Fig. 35: Patient K., teleradiograph before distraction. Distraction was performed using two-plane hinges at both levels.

Fig.36: Patient K., measurement of the initial length of the proximal regenerate (ILPR), starting point

Fig. 37: Patient K., measurement of the initial length of the proximal regenerate (ILPR), end point

Fig.38: Patient K., initial length of distal regenerate (ILDR), starting point

Fig. 39: Patient K., measurement of the initial length of the distal regenerate (ILDR), end point

Fig.40: Patient K., measurement of the planned length of the proximal regenerate (PLPR), starting point

Fig.41: Patient K., measurement of the planned length of the proximal regenerate (PLPR), end point

Fig.42: Patient K., measurement of the planned length of the distal regenerate (PDRR), starting point

Fig. 43: Patient K., measurement of the planned length of the distal regenerate (PDRR), end point

Fig. 44: Patient K., radiograph at the end of correction using an orthopedic hexapod

Fig. 45: Patient K., radiograph of the right leg in a direct projection during the fixation period

Fig. 46: Patient K., X-ray of the right leg in lateral projection during the fixation period

Fig.47: Patient K., appearance after removal of the device, front view

Fig.48: Patient K., appearance after removal of the device, side view

Fig. 49: Patient K., X-ray of the right leg in direct projection after removal of the device

Fig.50: Patient K., X-ray of the right leg in lateral projection after removal of the device

The method is carried out as follows.

1. Determine the axes of the proximal, distal and intermediate (intermediate) fragments using X-ray or CT data (in the presence of torsional deformation) during preoperative planning. Determine the apices of deformations, plan the levels of osteotomies and the positions of the supports of the external fixation apparatus (Fig. 1)

2. Intraoperatively, transosseous elements are inserted and one or two supports (depending on the length of the fragment) of the external fixation apparatus are mounted sequentially on the proximal, intermediate and distal fragments (Fig. 2)

3. In one embodiment of the invention, the connection of the supports is performed as follows: the hexapod strata are fixed to the proximal and distal supports, bypassing the intermediate one(s), the levels, except for the distal one, are connected by two-plane hinges.

In another embodiment of the invention, the connection of the supports is performed without a hexapod: the supports are connected at each level using two-plane hinges.

Osteotomies are performed according to preoperative planning. (Fig. 3)

4. After the surgical intervention, distraction begins on the 5th-7th day of the postoperative period.

5. Distraction is performed using two-plane hinges at all levels (Fig. 4). After achieving optimal interfragmentary diastasis (4-6 mm), the structure is reassembled by dismantling the two-plane hinges and installing hexapod struts (connecting the proximal and distal supports) and springs (connecting the intermediate support/s with the adjacent ones) (Fig. 5)

6. After performing the X-ray examination, the lengths of the strata and the sides of the triangles are measured (Fig. 6). The data obtained are used for calculation of correction using a computer program.

The algorithm of actions is given on the example of the computer program of the orthopedic hexapod "Ortho-SUV" of the modern version "OSF - 7.2. software"

7. Performing correction calculations using the orthopedic hexapod computer program

The first 8 steps of the orthopedic hexapod computer program algorithm are performed, namely: 7.1. The initial patient data are entered (lengths of strata and sides of triangles, indication of the correction date and type of strata). Fig. 6. 7.2. The radiographs in direct projection are loaded. Fig. 7. 7.3. The radiographs in lateral projection are loaded. Fig. 8.

7.4. Scale the radiographs in the AP projection. Fig. 9 7.5. Scale the radiographs in the lateral projection. Fig. 10. 7.6. Mark the striations on the radiograph in the AP projection. Fig. 11. 7.7. Mark the striations on the radiograph in the lateral projection. Fig. 12 7.8. Mark the axes of the fragments. At this step, the axis of the proximal bone fragment is taken as the axis of the base fragment, and the axis of the distal bone fragment is taken as the axis of the mobile fragment. Mark the axes of the proximal and distal fragments ("herringbone"), the axis of the distal fragment is combined with the axis of the proximal fragment, "ignoring" the intermediate fragment(s). Fig. 13. The "yellow dots" mark the level of the proximal edge of the distal fragment. Fig. 14

7.9. The initial boundaries of the displaced (distal/mobile) fragment are designated - the "yellow contour". The outlines of the "yellow contour" are aligned with the boundaries of the distal bone fragment. Fig. 15.

7.10. The correction results are simulated using the program algorithms and the final position of the mobile fragment is demonstrated (“red outline”). Fig. 16.

7.11. In the prototype, at the next step 11, the correction is calculated only for one of the 2-3 distraction regenerates, since the computer program can evaluate the change in length and calculate the optimal number of days only for one (using the so-called "Risk Structures" SAR#1 and SAR#2). In the prototype, the SAR#1 and SAR#2 points are used according to the program algorithm, in which the SAR#1 point is placed on the point of the proximal edge of the mobile fragment, which is most susceptible to displacement during the correction, and SAR#2 (if necessary, its use is not mandatory) on the area of soft tissues that are most exposed to risks.

In the claimed method, the lengths of each of the distraction regenerates are measured, as well as the values of change in their lengths during the correction period. Unlike the prototype, the SAR#1 and SAR#2 points are used as markers of the length measuring instrument.

The initial lengths are measured using radiographs loaded into the program, and the “red contour” (position of the distal fragment) and template (position of the intermediate fragment) are used to determine the final positions of the fragments and, as a consequence, the lengths of the regenerates (Fig. 17-18).

The Individual Intermediate Fragment Template is made as follows:

- a sheet of paper or other material is applied to the screen with the radiograph open on it;

- the contours of the intermediate fragment are outlined, transferring the boundaries onto paper;

- the template is cut out;

To check the manufacturing accuracy, the template can be applied to the contours of the intermediate fragment; their compliance is a sign of the correctness of the product (Fig. 17). To simulate the final position of the bone fragments, the template is placed between the proximal fragment and the "red contour" (simulating the position of the distal fragment) according to the "end-to-end" principle (Fig. 18). When measuring the final lengths of the regenerates, the edges of the template are taken as the edges of the intermediate fragment.

The sequence of actions in step 11 is as follows.

A) Perform, virtually using SAR#1 and SAR#2, a measurement of the initial length of the proximal regenerate (ILPR) - the distance between the point on the proximal edge of the intermediate fragment, which will be subject to maximum displacement during correction, and the opposite point on the distal edge of the proximal fragment.

To do this, in step 11, place the crosshair on one of the described points and press SAR#1 (Fig. 19), then move the crosshair to the opposite point and press SAR#2 (Fig. 20)

The resulting value of the NDP is saved for further calculations.

B) Perform, virtually using SAR#1 and SAR#, a measurement of the initial length of the distal regenerate (ILDR) - the distance between the point of the proximal edge of the distal fragment, which will be subject to maximum displacement during the correction, and the opposite point of the distal edge of the intermediate fragment. Fig. 21-22. Save the ILDR value obtained as a result of the measurement for further calculations.

B) The planned length of the proximal regenerate (PLPR) is measured by simulating the final position of the intermediate fragment using a template and measuring the distance between the most displaced point of the proximal edge of the intermediate fragment (the edges of the individual template are taken as the edges of the intermediate fragment) and the opposite point of the proximal fragment (i.e. the same points as in step A, but at the time of completion of the correction). Fig. 23-24.

D) In a similar manner to the measurement of the PDPR, the measurement of the planned length of the distal regenerate (PDDR) is performed. Fig. 25-26.

E) Calculate the values of the change in the lengths of each of the distraction regenerates at the levels of the proximal osteotomy using the formula (PDPR -_NDPR) and the distal osteotomy using the formula (PDDR -_NDDR)

G) The largest value of the change in the length of the regenerate is selected for further calculation of the optimal number of days required for correction. This value is divided by the rate of correction, which in the vast majority of cases is 1 mm per day (this rate is recommended, however, if necessary, the orthopedist may choose another one at his own discretion). The resulting number will correspond to the recommended number of days of correction.

Thus, the orthopedist, performing the calculation using the computer program of the orthopedic hexapod when implementing the “spring” technique, ensures a controlled rate of correction, not exceeding the recommended values of 1 mm per day.

The correction schedule is calculated in the program by entering the recommended number of correction days calculated in the previous step in the corresponding line, ignoring the number of days calculated automatically by the program. Fig. 27.

After the correction period is over and radiographic control is performed, the AVF is reassembled with the installation of two-plane hinges and the dismantling of the orthopedic hexapod and springs. Fig. 28-29.

9. Once radiographic consolidation has been established and clinical and dynamic tests are negative (Solomin L.N., 2015), the AVF is dismantled.

Clinical example

Patient K., 24 years old, complained of pain in the right knee joint. Examination revealed varus deformity of the bones of the right tibia (Figs. 30-33). The apex of the tibia deformity was located outside the bone boundaries, which suggests the presence of multi-apex deformity. For stable fixation of the proximal and distal bone fragments, it was decided to perform correction using the second rule of osteotomies (Fig. 34). Biplane hinges were used for distraction (Fig. 35). Distraction of 1 mm/day for each osteotomy was started on the 5th day. After reaching a diastasis of 6 mm, orthopedic hexapod struts and springs were mounted at each distraction level; biplane hinges were removed. When performing calculations in a computer program to determine the optimal number of days of correction, measurements of the lengths of regenerates were made using an individual template and the SAR#1 and SAR#2 indicators.

According to the measurement data, the initial length of the proximal regenerate in the zone that will be subjected to maximum displacement is 6 mm (Figs. 36, 37), the distal regenerate is 5.5 mm (Figs. 38, 39). When measuring the distance between the same points based on the planned position at the end of the correction, the obtained value was 9.6 mm (Figs. 40, 41) at the level of the distal regenerate, and 16 mm (Figs. 42, 43). As a result, at the end of the correction, the proximal regenerate will lengthen by 3.6 mm, and the distal one by 10.5 mm, which, according to the general rule, can be rounded up to 11 mm. For further calculations, a larger lengthening value was selected. The planned correction rate per vertex was 1 mm/day at the level of each fragment. Therefore, according to calculations, the optimal correction rate was 11 days. The correction was successfully completed (Fig. 44) within the calculated period. Then the apparatus was reassembled with the replacement of the hexapod struts and elastic tractions with two-plane hinges (Fig. 45, 46). The fixation period lasted 112 days, after which the apparatus was dismantled. The treatment was uneventful, the result was positive (Fig. 47-50).

Claims (5)

1. A method for correcting multi-apex deformities of long bones, including determining the axes of the proximal, distal, one or more intermediate fragments based on radiographs or CT data and the deformity axes, planning the osteotomy levels and the position of the supports of the external fixation device, intraoperative implementation of transosseous elements, installation of supports, performing osteotomy according to preoperative planning and subsequent distraction at the level of each of the deformity axes, installation of an orthopedic hexapod, measurement of its parameters and radiographic examination, as well as the use of a computer program into which the initial radiographs, hexapod parameters and parameters of the required position of the fragments are entered, then the axes of the distal and proximal fragments are virtually designated and aligned, and the terms of deformity correction are calculated and a correction schedule is generated, upon completion of which the orthopedic hexapod and springs are dismantled, replacing them with two-plane hinges, characterized in that after aligning the axes of the fragments, an additional virtual simulation is performed the results of the correction and mark the final position of the intermediate fragment, designate the contours of the intermediate fragment and make its material template, measure the lengths of each of the distraction regenerates, calculate the values of the change in the length of each of them at the levels of the proximal osteotomy during the correction period, select the largest value of the change in the length of the regenerate, determine the optimal number of days of correction by dividing the selected value of the change in the length of the regenerate by the planned rate of correction, enter the calculated number of days of correction into a computer program to generate a correction schedule. 2. The method according to item 1, characterized in that distraction is performed using two-plane hinges at all levels, and when the interfragmentary diastasis of 4-6 mm is reached, the two-plane hinges are dismantled and hexapod struts are installed, connecting the proximal and distal supports, and springs connecting one or more intermediate supports with adjacent ones. 3. The method according to paragraph 1 or 2, characterized in that, when aligning the axis of the distal fragment with the axis of the proximal fragment, the intermediate fragments are ignored, while marking the level of the proximal edge of the distal fragment when designating the initial boundaries of the distal bone fragment. 4. The method according to item 3, characterized in that the lengths of each of the distraction regenerates are measured, the initial lengths are measured according to the loaded radiographs, and the final positions of the fragments - the lengths of the regenerates are determined according to the position of the distal fragment using a template of the intermediate fragment. 5. The method according to claim 4, characterized in that when measuring the length of each of the distraction regenerates, the initial length of the proximal regenerate (ILPR) is measured - the distance between the point of the proximal edge of the intermediate fragment that will be subjected to maximum displacement during the correction and the opposite point of the distal edge of the proximal fragment, the initial length of the distal regenerate (ILDR) is measured - the distance between the point of the proximal edge of the distal fragment that will be subjected to maximum displacement during the correction and the opposite point of the distal edge of the intermediate fragment, the planned length of the proximal regenerate (PLPR) is measured, for which the final position of the intermediate fragment is simulated using a template and the distance between the most displaced point of the proximal edge of the intermediate fragment is measured, taking the edges of the individual template as the edges of the intermediate fragment, and the opposite point of the proximal fragment at the time of completion of the correction, the planned length of the distal regenerate is measured (PDDR), similar to the previous measurement of PDPR, the values of the change in the lengths of each of the distraction regenerates at the levels of the proximal osteotomy are calculated using the formula PDPR - NDPR and the distal osteotomy using the formula PDDR - NDDR.