RU237782U1 - Osteotomy template for the pubic, ilium and ischium bones when performing periacetabular osteotomy of the pelvis - Google Patents

Abstract

The utility model relates to the field of medicine, namely traumatology and orthopedics, and can be used in periacetabular osteotomy operations. A template for osteotomy of the pubic, ilium and ischium bones includes a body with a contact surface and three guides for osteotomies, wherein the contact surface is made congruent to the inner surface of the pelvis, limited by three lines, where the first line is the arcuate line of the ilium in the projection of the acetabulum, the second line runs 2-3 mm medial to the iliopodium, the third line runs from the lower edge of the anterior superior spine to the first line perpendicular to it, the guide for osteotomy of the pubic bone is made in such a way that its working plane corresponds to the second line and is perpendicular to the longitudinal axis of the superior branch of the pubic bone, the guide for osteotomy of the ilium is made in such a way that its working plane corresponds to the third line and is perpendicular to the plane of the ilium at the site of osteotomy, the guide for osteotomy of the ischium and ilium is made in such a way that its working plane is under Angled at 110-130° to the working plane of the ilium osteotomy guide, it directs the instrument during ischial osteotomy such that, in the horizontal plane, the projection lines running in the plane of the posterior column osteotomy form an equilateral triangle with the projection lines running along the lateral and medial surfaces of the posterior column. The technical result is to ensure the accuracy of osteotomies of the pubic, ilium, and ischium during periacetabular pelvic osteotomy, thereby preventing damage to the articular surface of the acetabulum without intraoperative X-ray control, thereby reducing radiation exposure.

Description

The utility model relates to the field of medicine, namely traumatology and orthopedics, and can be used in periacetabular osteotomy operations.

When performing a periacetabular osteotomy, it is important to establish the correct direction for the osteotomy plane. Typically, osteotomies of the ilium, pubis, and posterior pelvic column are performed using an oscillating saw and an osteotome under X-ray control [1]. The osteotomy direction is assessed using intraoperative X-ray control, which is performed repeatedly to prevent complications such as intra-articular osteotomy. Failure to directly visualize the osteotomy can result in damage to the acetabulum, which subsequently leads to rapid progression of deforming arthrosis.

The closest in technical essence is a device for determining the level of osteotomy and transposition of the greater trochanter in case of its hypertrophy [2], which is an overlay made on a 3D printer, with the possibility of its tight fit on the lateral surface of the proximal femur, and containing a groove for determining the level of osteotomy.

However, this device is not suitable for performing periacetabular osteotomies because it has a completely different pad shape, preventing placement on the pelvic bone surface. Furthermore, the existing groove on this device prevents osteotomies of the ilium, pubis, and ischium from being performed in the correct direction.

Currently, the direction of the osteotomy lines of the ilium, pubis and ischial bones of the pelvis is determined intraoperatively during X-ray control, after which the bones are positioned and fixed in the required position.

The disadvantage of this periacetabular osteotomy method is its high complexity, as determining the osteotomy plane directions relies on the surgeon's experience and requires constant intraoperative X-ray monitoring, which increases the influence of the "human factor" and creates the risk of intraoperative complications. The use of multiple X-ray monitoring increases radiation exposure for both the patient and the medical staff in the operating room, increasing the risk of long-term adverse effects.

The technical challenge is to develop a device for performing periacetabular osteotomy, allowing osteotomies of the pubic, ilium and ischium to be performed without intraoperative X-ray control, with high accuracy and without the risk of damage to the hip joint.

The technical result consists in ensuring the accuracy of osteotomy of the pubic, ilium and ischial bones when performing periacetabular osteotomy of the pelvis in order to exclude damage to the articular surface of the acetabulum without intraoperative X-ray control, which reduces radiation exposure.

The technical result is achieved by a template for osteotomy of the pubic, ilium and ischial bones, including:

a body with a contact surface and three guides for osteotomies,

in this case, the contact surface is made congruent to the inner surface of the pelvis, limited by three lines,

where the first line is the arcuate line of the ilium in the projection of the acetabulum,

the second line runs 2-3 mm medial to the iliac-pubic tubercle,

the third line runs from the lower edge of the anterior superior spine to the first line perpendicular to it,

the guide for osteotomy of the pubic bone is designed in such a way that its working plane corresponds to the second line and is perpendicular to the longitudinal axis of the superior branch of the pubic bone;

the guide for osteotomy of the ilium is designed in such a way that its working plane corresponds to the third line and is perpendicular to the plane of the ilium at the site of osteotomy;

the guide for osteotomy of the ischium and ilium is designed in such a way that its working plane is at an angle of 110-130° to the working plane of the guide for osteotomy of the ilium and guides the instrument during osteotomy of the ischium in such a way that in the horizontal plane the projection lines passing in the plane of osteotomy of the posterior column form an equilateral triangle with the projection lines passing along the lateral and medial surfaces of the posterior column.

In a particular embodiment of the device, the guides for osteotomies are made 2-5 mm high and/or through holes are made in the housing for fixing elements.

The creation of a contact surface congruent with the internal surface of the pelvis onto which it is applied ensures precise and stable positioning of the torso, taking into account individual anatomical bone landmarks, regardless of the patient's position in space. This, in turn, ensures precise and stable positioning of the osteotomy guides along the specified (planned) bone cutting lines. The guides themselves ensure contact between the oscillating saw blade and the osteotome, preventing their deviation from the plane and trajectory of the osteotomy. This, combined with the working planes of the two osteotomy guides being set at a predetermined angle (110-130°), ensures passage of the oscillating saw blade or osteotome into the bone mass behind the hip joint, preventing damage. All this ensures controllability and ease of osteotomy of the pubic, ilium, and ischium, ensuring the possibility of obtaining an acetabular fragment with an optimal configuration for its repositioning during subsequent surgery. In addition, the time of surgical intervention is reduced, the need for intraoperative X-ray control is eliminated (reduces radiation exposure), and the risk of damage to the acetabulum is eliminated, and therefore, the effectiveness of treatment is ensured.

Specific template design variations enhance the stated technical result. For example, the osteotomy guides, 2-5 mm high, feature a projection height that maximizes blade contact while simultaneously taking into account the limited space available for surgery. Through-holes in the body allow the template to be secured to the bone surface, eliminating the risk of displacement during surgery.

The essence of the claimed device is explained by the drawings:

Fig. 1. Template for osteotomy of the pubic, ilium and ischium bones (bottom view).

Fig. 2. Template for osteotomy of the pubic, ilium and ischium bones (oblique view from above and from the side).

Fig. 3. Osteotomy template for the pubic, ilium and ischium bones, oriented to the congruent contact surface of the ilium (contact surface shown, device raised 2 cm above the contact surface).

Fig. 4. Osteotomy of the pubic bone (the device is fixed to the pelvic bones, the osteotome is immersed in the pubic bone).

Fig. 5. Osteotomy of the ilium (the device is fixed to the pelvic bones, the oscillating saw is immersed in the ilium).

Fig. 6. Osteotomy of the posterior ischium and ilium bones that form the posterior column of the pelvis (the device is fixed to the pelvic bones, the osteotome is immersed in the posterior column).

Fig. 7. The plane of the pubic bone osteotomy (the osteotomy lines along which the fragment subject to correction is separated are shown).

Fig. 8. The plane of the ilium osteotomy (the osteotomy lines along which the fragment subject to correction is separated are shown).

Fig. 9. Plane of osteotomy of the posterior column (osteotomy lines along which the fragment subject to correction is separated are shown).

Fig. 10. Clinical example.

Fig. 11. Clinical example.

Fig. 12. View of the right pelvic hemiring in the horizontal plane (lines running along the lateral and medial surfaces of the posterior column and a projection line running in the plane of the osteotomy of the posterior column are shown).

The figures indicate:

1 – body;

2 – contact surface;

3 – guide for osteotomy of the pubic bone;

4 – pubic bone;

5 – guide for iliac osteotomy;

6 – ilium;

7 – guide for osteotomy of the ischium and ilium, which make up the posterior column of the pelvis;

8 – ischium;

9 – inner surface of the pelvis;

10 – first line;

11 – second line;

12 – third line;

13 – acetabulum;

14 – iliopubic tubercle;

15 – anterior superior spine;

16 – working plane of guide 3 for osteotomy of the pubic bone;

17 – working plane of guide 5 for osteotomy of the ilium;

18 – working plane of guide protrusion 7 for osteotomy of the ischium and ilium bones that make up the posterior column of the pelvis;

19 – through holes for fixing elements (spokes);

20 – fixing elements (spokes);

21 – greater sciatic notch;

22 – osteotome (oscillating saw, chisel);

23 – first plane of osteotomy (pubic bone);

24 – second plane of osteotomy (ilium);

25 – third plane of osteotomy (posterior column of the pelvis);

26 – fourth plane of osteotomy;

27 – acetabular fragment of the pelvis;

28 – cortical screws.

A template for osteotomy of the pubic, ilium and ischium bones when performing periacetabular osteotomy of the pelvis includes a body 1 with a contact surface 2, a guide 3 for osteotomy of the pubic bone 4, a guide 5 for osteotomy of the ilium 6 and a guide 7 for osteotomy of the ischium 8 and ilium 6 bones that make up the posterior column of the pelvis.

The contact surface 2 is made congruent to the inner surface 9 of the pelvis, limited by three lines 10, 11 and 12.

The first line 10 is the arcuate line (linea arcuata) of the ilium 6 in the projection of the acetabulum 13.

The second line 11 runs 2-3 mm medial to the iliopubic tubercle 14 (eminentia iliopubica).

The third line 12 runs from the lower edge of the anterior superior spine 15 to the first line 10 perpendicular to it.

Guides 3, 5 and 7 can be made with a thickness corresponding to the thickness of housing 1 or slightly enlarged relative to the housing, in particular in the form of protrusions 2-5 mm high.

Guide 3 for osteotomy of pubic bone 4 is designed in such a way that its working plane 16 corresponds to the second line 11 (i.e., runs along the second line 11). Working plane 16 is perpendicular to the longitudinal axis of the superior ramus of the pubic bone.

Guide 5 for osteotomy of ilium 6 is designed such that its working plane 17 corresponds to the third line 12, stopping short of the first line 10 by a distance S equal to 10-15 mm. Working plane 17 is perpendicular to the plane of the ilium at the osteotomy site.

The guide 7 for osteotomy of the ischium 8 and ilium 6 bones, which make up the posterior column of the pelvis, is designed in such a way that its working plane 18 is at an angle of 110-130° to the working plane 17 of the guide 5 for osteotomy of the ilium 6 and guides the instrument during osteotomy of the ischium in such a way that in the horizontal plane, the projection lines passing in the plane of the osteotomy of the posterior column form an equilateral triangle with the projection lines passing along the lateral and medial surfaces of the posterior column (Fig. 12). The said angle is determined individually during preoperative planning. This angle depends on the anatomy of the patient: the spatial position and size of the pelvic bones.

the guide for osteotomy of the ischium and ilium is made in such a way

Guides 3, 5 and 7 can be made integral with body 1 or can be made in the form of projections fixed to body 1.

In the body 1, through holes 19 are made for fixing elements 20 (spokes), made in such a way that damage to the joint is excluded when fixing elements 20 are passed through them.

The claimed template can be manufactured based on a preliminary computed tomography scan of the patient's pelvis using medically approved materials used for 3D printing.

The device is used as follows.

During the preoperative planning stage, a CT scan of the patient's pelvis is performed, and a periacetabular osteotomy is modeled, specifically determining the configuration of the required acetabular fragment and its repositioning parameters. Following this, a template for osteotomy of the pubic, ilium, and ischium is modeled based on the identified bony landmarks on the patient's inner pelvis and manufactured, for example, using a 3D printer. Next, the pelvic bones are accessed, and the inner surface (9) of the pelvis is exposed, extending from the border of the iliopodium (14) (Fig. 3, Figs. 8-9) to the greater sciatic notch (21) (Figs. 4-7).

The template is placed on the exposed inner surface 9 of the pelvis in such a way that the contact surface 2 coincides with the surface of the pelvis, from the medial border of the iliopunic tubercle 14 (Fig. 3, Fig. 8-9) to the third line 12 (Fig. 3-4, Fig. 6), passing from the lower border of the anterior superior spine 15 (Fig. 3-11) perpendicular to the first line 10 (Fig. 3-7) and fixed with knitting needles 20 (Fig. 4-6) through holes 19 (Fig. 1-6).

Next, the bones are cut. For this, the blade of the osteotome 22 (Fig. 4, Fig. 7) is guided along the working plane 16 of the guide 3, cutting the pubic bone 4 along the second line 11 in the first plane of the osteotomy 23 (Fig. 7).

After this, the blade of the osteotome 22 (Fig. 5) is guided along the working plane 17 of the guide 5, crossing the ilium 6 along the third line 12 along the second plane of the osteotomy 24 (Fig. 8).

Then the blade of the osteotome 23 (Fig. 4, 5, 6) is guided along the working plane 18 of the guide 7, crossing the ilium 6 and the ischium 8, which make up the posterior column of the pelvis, in the third plane of osteotomy 25 (Fig. 9).

Using a chisel (not shown in the figure), the ischium 8 is cut in the fourth plane of osteotomy 26, obtaining a movable acetabular fragment 27 (Fig. 7-9, Fig. 11) containing the acetabulum 13 (Fig. 3, Fig. 9).

Reposition is performed by moving the acetabular fragment 27 (Fig. 7-9, Fig. 11) to the correct position, in which it is fixed with 3-4 cortical screws 28 (Fig. 11), passing from the ilium, through the osteotomy plane (Fig. 7) into the acetabular fragment 27 (Fig. 7-9, Fig. 11). The wound is closed in the generally accepted manner.

We illustrate the practical use of the method with a clinical example.

Clinical example 1

Patient K.E.A., 29 years old (Fig. 10), was hospitalized for symptomatic dysplasia of the left hip joint (Wiberg angle = 10.9 ^° , Tonnis angle = 25.6 ^° , femoral head extrusion index = 38.17%). Left periacetabular osteotomy was performed using a template for osteotomy of the pubic, ilium, and ischium bones according to the described technique, which reduced the need for intraoperative X-ray control and the radiation load for the patient and the surgical team. The angle between the guides for osteotomy of the ilium and ischium was 122 ^° . The use of this device ensured that periacetabular osteotomy was performed in accordance with the preoperative plan and made it possible to avoid uncontrolled intraoperative intra-articular fractures of the acetabulum and achieve the calculated angles. Postoperative radiographs (Fig. 11) show a satisfactory position (Wiberg angle=31.6 ^o , Tonnis angle=8 ^o , femoral head extrusion index=12.97%) of the acetabulum fragment fixed with three 28 cortical screws (Fig. 11).

Clinical example 2

Patient S.P.S., 20, underwent inpatient treatment for symptomatic dysplasia of the left hip joint (Wiberg angle = 19.2 ^o , Tonnis angle = 17.2 ^o , femoral head extrusion index = 29%). Periacetabular osteotomy was performed on the left using a template for osteotomy of the pubic, ilium and ischium bones during periacetabular osteotomy according to the described technique. The angle between the guides for osteotomy of the ilium and ischium was 115 ^o . The use of this device ensured that periacetabular osteotomy was performed in accordance with the preoperative plan and avoided errors in performing osteotomies of these bones. The degree of correction of the Wiberg angle was 16.70 ^o , the degree of correction of the angle of inclination of the acetabulum (Sharp angle) was 12 ^o . Postoperative radiographs show a satisfactory position (Wiberg angle = 35.9 ^o , Tonnis angle = 5.6 ^o , femoral head extrusion index = 10%) of the acetabulum fragment fixed with three cortical screws.

Clinical example 3

Patient T.V.O., 19, underwent periacetabular osteotomy using a template for osteotomy of the pubic, ilium, and ischium during periacetabular osteotomy according to the described technique for symptomatic dysplasia of the right hip joint (Wiberg angle = 10.40 ^o , Tonnis angle = 20.8 ^o , femoral head extrusion index = 35.89%). The angle between the guides for osteotomy of the ilium and ischium was 127 ^o . The degree of correction of the Wiberg angle was 21.70 ^o , the degree of correction of the angle of inclination of the acetabulum (Sharp angle) was 12.9 ^o . Postoperative radiographs show a satisfactory position (Wiberg angle = 32.10 ^o , Tonnis angle = 0.8 ^o , femoral head extrusion index = 15.68%) of the acetabulum fragment fixed with three cortical screws.

Thus, the claimed utility model provides an effective device for performing periacetabular osteotomy of the ilium, pubic bones and posterior column of the pelvis, ensuring high precision in performing bone osteotomy while minimizing radiation damage and the risk of damage to the acetabulum.

Bibliography:

1. Tibor L. M., Sink E. L. Periacetabular osteotomy for hip preservation //Orthopedic Clinics of North America. – 2012. – T. 43. – No. 3. – pp. 343-357.

2. Patent No. 2777431 C1 Russian Federation, IPC A61B 17/56. Device for determining the level of osteotomy and transposition of the greater trochanter in case of its hypertrophy: No. 2021107802: declared 23.03.2021 : published 03.08.2022 / P. I. Bortulev, S. V. Vissarionov, M. S. Poznovich, I. Yu. Applicant Federal State Budgetary Institution "G.I. Turner National Medical Research Center for Pediatric Traumatology and Orthopedics" of the Ministry of Health of the Russian Federation. – EDN TOPIBW.

Claims (11)

1. Template for osteotomy of the pubic, ilium and ischium bones when performing periacetabular osteotomy of the pelvis, including a body with a contact surface and three guides for osteotomies, in this case, the contact surface is made congruent to the inner surface of the pelvis, limited by three lines, where the first line is the arcuate line of the ilium in the projection of the acetabulum, the second line runs 2-3 mm medial to the iliac-pubic tubercle, the third line runs from the lower edge of the anterior superior spine to the first line perpendicular to it, the guide for osteotomy of the pubic bone is designed in such a way that its working plane corresponds to the second line and is perpendicular to the longitudinal axis of the superior branch of the pubic bone, the guide for osteotomy of the ilium is designed in such a way that its working plane corresponds to the third line and is perpendicular to the plane of the ilium at the site of osteotomy, the guide for osteotomy of the ischium and ilium is designed in such a way that its working plane is at an angle of 110-130° to the working plane of the guide for osteotomy of the ilium and guides the instrument during osteotomy of the ischium in such a way that in the horizontal plane the projection lines passing in the plane of osteotomy of the posterior column form an equilateral triangle with the projection lines passing along the lateral and medial surfaces of the posterior column. 2. The template according to claim 1, characterized in that the guides for osteotomies are made with a height of 2-5 mm. 3. The template according to paragraph 2, characterized in that through holes for fixing elements are made in the body.