RU2747071C1 - Method of insertion of transpedicular screws in the chest and lumbar spine - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to medicine, namely to surgery of the spine, and can be used to treat patients with deformities of the spine with congenital deformity of the thoracic and lumbar spine against the background of a violation of the formation and segmentation of the vertebrae. A dorsal approach to the posterior column of the spine is performed. A channel for the pedicle screw is formed. The pedicle screw is inserted into the canal. The insertion site of the screw is selected in the area between the transverse process, the upper and lower articular processes, at the point of their intersection, the place of insertion of the pedicle screw in the pedicle is prepared. A funnel-shaped depression is formed, for this the cortical plate is removed, the cancellous bone of the leg is exposed. The cancellous bone of the vertebral pedicle is bougie. The cancellous bone is removed to the base of the leg. A canal is formed in the vertebral body. The pedicle screw is inserted into the canal. In particular embodiments of the method, the cortical plate is removed with Luer pliers or a bur, and the depression in the pedicle is filled with bone cement.

EFFECT: method provides control of pedicle screw placement, accuracy of pedicle screw insertion, possibility of visual intraoperative control of screw position in the arch pedicle and reduction of the likelihood of incorrect screw insertion without using technically sophisticated navigation equipment or specially made devices by preparing the pedicle screw insertion point and forming a depression.

3 cl, 2 ex, 3 dwg

Description

The field of technology.

The invention relates to medicine, neurosurgery, namely spinal surgery. It is used in the treatment of patients with deformities, degenerative-dystrophic and traumatic changes in the spine; it is used to insert screws into the vertebra during transpedicular fixation of the vertebrae with peculiar screws in an open way.

State of the art.

Known methods for correcting spinal deformity involve the use of modern versions of CDI (Cotrel-Dubousset instrumentation) instrumentation for transpedicular fixation (source [1]: New universal instrumentation in spinal surgery. Sotrel J. Dubousset I. Guillaumat M. Clinical orthopedics and related research: February 1988 - Volume 227 - Issue - pp. 10–23. New universal instrumentation in spinal surgery. Cotrel Y, Dubousset J, Guillaumat M. Clin Orthop. 1988; 227: 10–23); source [2]: History of spinal screw and pedicle screw fixation. Mark B. Cabins and James N. Weinstein. Iowa Ortop Jv. 1991; 11: 127-136 pp. PMC2328959. The History of Vertebral Screw and Pedicle Screw Fixation. Mark B. Kabins and James N. Weinstein. Iowa Orthop Jv. 11; 1991 PMC2328959). The key feature of the methods is the passage of transpedicular screws into the vertebral body through the pedicle of the arch, or fixation with hooks for the posterior support complex (arches and transverse processes of the vertebrae), through the dorsal approach. The maximum diameter of the pedicular screw for pedicle fixation (TPF) through the pedicle is always limited by the width of the pedicle (root) of the arch.

When pedicle screws are inserted in TPF, as a rule, the “free hand” technique is used; it does not require special navigation equipment. The use of the “free hand” technique is based solely on the experience of the surgeon and his understanding of the spatial location of the screw insertion point and the direction and trajectory of screw insertion. Intraoperative imaging is also used to control the direction of insertion, but rarely, more often it is not used at all, therefore, the use of the “free hand” technique is possible only with open interventions. The accuracy of screw insertion into the vertebra can be increased by controlling the direction of insertion, for example, by direct visualization and palpation of the medial walls of each of the roots (pedicles) of the arches, for example, after decompression of the spinal canal. The “free hand” technique involves the surgeon using natural anatomical landmarks within the operating field, which would allow the correct localization of the pedicle screw insertion point at the level of each of the arch roots. After the required point is localized, local decortication is performed at this point with the help of an awl, nippers or bur. A straight or curved pedicle probe is placed at this point. Before immersing the probe into the thickness of the root of the arch, the surgeon must evaluate the necessary trajectory of its introduction both in the sagittal and in the axial (transverse) plane. The probe is immersed rather slowly, with constant rotational movements and with little pressure on it, while the surgeon must use his dominant hand. The blunt working end of the probe is designed in such a way that the risk of perforation of the cortical wall of the arch root is minimized. Do not use excessive force when introducing the probe, otherwise the probe can perforate the vertebral body or lead to a fracture of the arch root. Thus, with the help of the probe, a channel is formed for the introduction of the pedicular screw, after which the probe is removed. At the next stage, a probe is inserted into the canal, with the help of which the integrity of the cortical walls of the arch root and the required length of the pedicular screw are assessed. If the integrity of the arch root is not broken, then a thread is formed in the canal and a pedicular screw of the required length is inserted. If a defect is found in one of the cortical walls of the root of the arch, the probe is inserted again and an attempt is made to correct the trajectory of the canal. After the canals are formed in each of the roots of the arches, which are subject to stabilization, a Kirschner wire or a pedicular marker is inserted into each of the canals, and only then, in order to make sure that their location is correct, an intraoperative radiography is performed.

The accuracy and direction of screw insertion can vary over a wide range, which depends primarily on the personal experience and skills of the operating surgeon. In this case, since the execution of the channel for the screw is carried out within the body of the leg, the choice of the direction of introduction is limited by the perimeter of the leg. The surgeon inserting a screw into the canal corresponding to the size of the screw body does not have the ability to adjust its position to ensure its optimal position in the vertebral body.

Known methods for determining the direction of insertion of transpedicular screws using navigation based on images from a computed tomograph and fluoronavigation (source [3]: [Ph. Merloz, J. Tonetti, M. Milaire, G. Kerschbaumer, S. Ruatti, S. Dao-Lena : Contribution of 3D imaging in spinal surgery. - The genius of orthopedics, No. 1, 2014, pp. 51-57 .; source [4]: M. Richter, V. Cakir, R. Schmidt / SPINE-2005. Vol. 30 , N. 20, pp. 2280-2287.) In this case, the direction of the screw is controlled directly on the computer screen in two or three planes.

There is a known method of extrapedicular screw introduction in the thoracic spine (source [5]: Makarevich S. V., Satskevich D. G. Extrapedicular technique for introducing screws in the thoracic spine // Vestnik VSMU, 2004, volume 3, No. 4). The screw is installed lateral to the root of the arch through the transverse process and the costal-vertebral joint, while there is no limitation of the maximum screw diameter by the width of the arch root (as in classical TPF). With this technique, it is possible to use screws of any diameter available in spine surgery.

One of the known methods (source [6]: patent RU 2620355) includes preoperative planning of the trajectory of the introduction of transpedicular screws on the basis of computed tomography of the spine and the installation of screws along planned trajectories. Any program for viewing medical images in DICOM format can be used for planning, which is capable of constructing multiplanar reconstructions (MPR) in an arbitrary plane (there are many such programs in open sources, including free and shareware, for example: "Onis 2.4 Free Edition "," Inobitec DICOM Viewer "," E-Film ", etc.). In multiplanar reconstruction in the plane of screw insertion, the most optimal trajectories of passage (through the pedicles of the arch into the vertebral bodies) are selected for each screw. For each vertebra, a marking map is formed, including slices in three planes and displaying their entry trajectories on the plane of screw introduction, the distance between the screw insertion points, the distance between the supraspinatus ligament and the point on the screw trajectory at the same level. Intraoperatively, the points of screw insertion are determined on the basis of the created marking map, the angle of entry in the sagittal plane is determined by fluoroscopy in the lateral projection, the angle of convergence in the axial plane is determined indirectly by measuring the distance between the apex of the spinous process (supraspinous ligament) and the instrument used to install the screw. The technique allows for accurate insertion of transpedicular screws, does not require the use of expensive navigation systems, allows for X-ray control only in the lateral projection, which reduces the radiation exposure to the patient and staff and makes it possible to use a conventional (non-radiolucent) operating table.

A known method for determining the direction of insertion of transpedicular screws by virtual fluoroscopy based on computer navigation (source [7]: Foley K.T. et al .: Virtual fluoroscopy: computer-assisted fluoroscopic navigation. - Spine, Vol. 26, 2001, p. 347 -351). At the same time, using infrared sensors installed at certain anatomical points and data from preoperative computed tomography examination of the damaged spine, the direction of the screw is controlled directly on the computer screen in two or three planes.

The disadvantage of these methods, limiting their widespread use, is the need to use technically complex and expensive equipment, as well as appropriate software.

With the advent of computer navigation and intraoperative CT control, the placement of transpedicular screws becomes easier, and the requirements for the surgeon's experience are reduced. However, not all clinics are equipped with CT and C-arms, let alone modern navigation systems. The “free hand” method for introducing screws without using special navigation equipment has significant advantages, but it requires significant practical skills and experience of the surgeon, and also requires a decrease in the likelihood of damage to the stem wall during canal formation, and a decrease in the likelihood of incorrect screw insertion into the vertebral body.

The essence of the technical solution.

The objective of the invention is to create a method for the passage of pedicle screws into the vertebral body in the thoracic and lumbar spine with an improved "free hand" method, which makes it easier to control the passage of the pedicle screw, ensure the accuracy of insertion of the pedicle screws, and reduce the likelihood of incorrect screw insertion, and the number of malpositions, without the use of technically sophisticated navigation equipment or specially made devices, with a reduction in the duration of preoperative preparation.

The technical result consists in the introduction of the pedicle screw into the vertebra, with the provision of the possibility of visual intraoperative control of the position of the screw in the pedicle of the arch, and a decrease in the likelihood of incorrect screw introduction, without the use of technically sophisticated navigation equipment or specially made devices.

The technical result is achieved by the fact that in the method of introducing pedicle screws in the thoracic and lumbar regions with transpedicular fixation, a dorsal access to the posterior column of the spine is performed, a channel for the pedicle screw is formed, the pedicle screw is inserted into the canal, and the place of screw insertion is selected on the area formed by the transverse process , the upper and lower articular process, prepare the insertion site of the pedicle screw in the pedicle, form a funnel-shaped depression, for this part of the cortical plate is removed, the cancellous bone of the pedicle is exposed, the cancellous bone of the vertebral pedicle is expanded with a pedicular scan, cancellous bone is removed to the base of the pedicle, the canal in the vertebral body, the pedicle screw is inserted into the canal.

Traspedicular screws are inserted transpedicularly intracorporeally using the free hand method.

A feature of the method is the preparation of the place (point) of the pedicle screw insertion, the formation of a depression, as a result, the surgeon has the opportunity to control the direction of the screw insertion into the vertebral body, thereby reducing the risk of malposition.

In one embodiment, the recess in the stem is filled with bone cement after the screw has been placed to provide additional fixation for the screw body.

The method is illustrated by illustrations, which show:

Figure 1 - shows the point of introduction of the screw, Luer pliers removed a part of the cortical plate at the leg in the place of the deepening formed by the transverse process, the superior and inferior articular processes;

FIG. 2 - it is shown sequentially (from left to right) the stages of bougienage by the development of the cancellous bone of the vertebral pedicle;

FIG. 3 - shows the installation of the screw into the vertebral body through the bougie pedicle of the vertebral arch;

The figures indicate:

1 screw;

2nd entry point;

3-pedicle of the vertebra;

4-sweep;

5-vertebral body;

6-recess in the leg.

The method is carried out as follows.

Method of introducing transpedicular screws in the thoracic and lumbar regions with transpedicular fixation. It is used in the treatment of patients with deformities, degenerative-dystrophic and traumatic changes in the spine; it is used to insert screws into the vertebra during transpedicular fixation of the vertebrae with peculiar screws in an open way.

Example 1. Installation of a screw in the thoracic region. For the introduction of the screw 1 (figure 3) perform dorsal access to the posterior column of the spine. The insertion site 2 (Fig. 1) of the screw 1 is selected at the site formed by the transverse process, the superior and inferior articular processes of the vertebra. Prepare the insertion site 2 of the pedicle screw 1 in the leg 3 (Fig. 2), form a depression 6 (Fig. 2) in the form of a funnel, for this part of the cortical plate is removed, the cancellous bone of the leg 3 is exposed, the spongy bone of the leg 3 is exposed with a pedicle scan 4 vertebra, remove the cancellous bone to the base of the leg 3. Form a channel for the pedicle screw 1 in the body 5 (figure 3) of the vertebra, produce the installation of the pedicle screw 1 into the canal.

Part of the cortical plate is removed with Luer pliers,

In another embodiment, a portion of the cortical lamina is removed with a bur.

Dorsal approach to the posterior column of the spine is performed in accordance with preoperative planning from a midline incision. The length of access is determined by the instrumentation zone. It is preferable to place transpedicular anchor points bilaterally in accordance with the principles of CD fixation.

Traspedicular screws are inserted transpedicularly intracorporeally using the free hand method.

A feature of the method is the preparation of the place (point) of the pedicle screw insertion. The screw insertion site is a "funnel" (depression) formed at the intersection of the transverse process, the superior and inferior articular processes. In the area of the proposed insertion point of the screw, instead of a local puncture of the cortical plate with an awl, nippers or bur, part of the cortical plate is removed with Luer pliers, thus exposing the cancellous bone. Further (bypassing the awl stage), the pedicular scan is used to bougie the vertebral pedicle through the "funnel" (depression) formed by the transverse process, the superior and inferior articular processes. The vertebral pedicle is bougiened with a reamer, while a canal is formed, cancellous bone is removed to the base of the pedicle. (The reamer, as it were, slides from the second cortical into the funnel of the vertebral pedicle in the cancellous bone). Since the upper cortical plate at the insertion point is removed with Luer nippers (or bur), the tactile sensations when the screw is inserted, when the cancellous bone passes, and it becomes possible to control the direction of screw insertion into the vertebral body, which reduces the risk of malposition.

Before surgery, x-ray computed tomography of the thoracic or lumbar spine is performed. X-ray images determine the absence of developmental anomalies in the anatomical structures of the vertebrae in order to determine the possibility of using this method. If there are no developmental abnormalities, surgery is performed. An incision is made in the soft tissues. During surgery, careful skeletonization of the posterior anatomical structures of the vertebrae subjected to transpedicular fixation is required. The following anatomical structures of the vertebra are exposed from soft tissues: spinous process, arch, articular processes and vertebral legs.

If necessary, a thread is cut into the channel in the body 5 with a tap, then the pedicle screw 1 is tightened.

Thus, damage to the walls of the leg 3 is excluded, visual control over the screw and the possibility of adjusting its position when inserted into the body of the 5th vertebra are provided.

Example 2. Installation of screws in the lumbar spine. It is carried out in the same way as described in example 1. In addition, the depression in the stem is filled with bone cement, after the screw is installed, which makes it possible to provide additional fixation of the screw body in the most loaded part of the spine.

The method can be applied in specialized medical institutions that do not have navigation equipment, with transpedicular fixation of the thoracic and lumbar spine. It provides precise insertion of transpedicular screws into the vertebral bodies.

Claims (3)

1. A method of introducing pedicle screws in the thoracic and lumbar regions during transpedicular fixation, characterized by the fact that dorsal access to the posterior column of the spine is performed, a channel for the pedicle screw is formed, the pedicle screw is inserted into the canal, and the place of screw insertion is chosen in the area between the transverse process , the upper and lower articular processes, at the point of their intersection, prepare the insertion site of the pedicle screw in the pedicle, form a funnel-shaped depression, for this the cortical plate is removed, the cancellous bone of the pedicle is exposed, the cancellous bone of the vertebral pedicle is rounded, the cancellous bone is removed to the base of the pedicle , form a canal in the vertebral body, insert a pedicle screw into the canal. 2. The method according to claim. 1, characterized in that the cortical plate is removed with Luer pliers or a bur. 3. The method according to claim 1, characterized in that the recess in the stem is filled with bone cement.

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