RU2816064C1 - Device for mechanical transosseous introduction of schanz rods - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention refers to medical equipment, namely to a device for mechanical transosseous introduction of Schanz rods. Device for mechanical transosseous introduction of Schanz rods is made in the form of a nozzle, contains a threaded rod, a tall nut and two nuts from a set of the Ilizarov apparatus. Tall nut is locked at one end of the threaded rod by means of one nut from the set of the Ilizarov apparatus and is intended for screwing the end of the Schanz rod into it with its subsequent fixation by means of opposite rotation of the other nut from the set of the Ilizarov apparatus and the tall nut. Free end of the threaded rod is intended for its fixation in the electric drill chuck.

EFFECT: use of the invention allows providing a simple, fast and reliable connection with the Schanz rod and the drill chuck and their disconnection, which significantly reduces the time of using the device and the duration of the entire surgical intervention.

1 cl, 2 dwg

Description

The invention relates to medical equipment, namely to devices used in traumatology and orthopedics.

Relevance

A feature of the provision of medical care to victims with fractures of the long bones of the extremities as part of polytrauma in the acute period is the need to combine the “golden hour” rule (with urgent anti-shock measures) and the concept of “Domage control” (staged medical care with minimally traumatic emergency surgical interventions in the first day after injury and preventing the so-called “second blow”, which disrupts the already unstable general condition of the patient). The more severe the injury and the patient’s condition, the simpler and more atraumatic the means of primary stabilization of the fracture zone should be, and the final osteosynthesis should be delayed. Consequently, the main requirements for the primary fixation of bone fragments are: minimal invasiveness and duration of intervention.

Analogs

The method of choice for stabilizing high-energy fractures of skeletal bones in the acute period of polytrauma is extrafocal osteosynthesis with external fixation devices (EFD), the main advantage of which, along with stable fixation of bone fragments, is atraumaticity. Based on the type of transosseous elements used, a distinction is made between wire, rod and wire-rod AVFs.

Criticism of analogues

Wire (in particular, the Ilizarov apparatus) and wire-rod AVFs are distinguished by their atraumatic nature, which is consistent with the “Domage control” concept). However, the significant labor and time costs of their use are not consistent with the “golden hour” rule and make them suboptimal for primary osteosynthesis, especially in conditions of polytrauma.

Prototype

We chose a rod AVF as a prototype device (Ankin L.N., Ankin N.L. Practical traumatology. European standards of diagnosis and treatment - M.: Kniga-plus, 2002. - 480 pp. - P.-71-75 ), which is optimal in the acute period of polytrauma, since it combines minimal invasion and short duration of surgical intervention. Subsequently, after the changes in the homeostasis of the victim’s body have been relieved, AVFs are usually converted into final osteosynthesis, for example, intramedullary osteosynthesis with locked rods.

AVF is mounted in the form of four frame structures, each of which has its own characteristics: one-sided (unilateral) single-plane, one-sided two-plane, two-sided (bilateral) single-plane, two-sided two-plane external frame of the device. A one-sided single-plane frame is used especially often, since it is simpler, faster to install and more effective for neutralizing angular and rotational displacement moments during high-energy fractures in patients with polytrauma, and also significantly facilitates the care of seriously ill patients in an unconscious state (for example, with severe head injuries in the composition polytrauma).

Reduction of the fracture is performed on the operating table manually or with skeletal traction. For fractures of the tibia bones 3 cm above the line of the ankle joint, an incision-prick is made along the anteromedial surface of the tibia perpendicular to the tibia. Using a protective sleeve, a 3.5-mm drill is used to drill holes through both cortices. Some authors recommend widening the hole in the near cortex with a 4.5-mm drill. A Shants rod is inserted bicortically into the formed hole. Its transosseous insertion is performed manually using a special wrench or, most often, a cross-shaped die from the Ilizarov apparatus set at the base end of the Shants rod. Typically, an 82-mm die is secured to the Shants rod by locking - that is, by counter-rotating two nuts placed on it, between which the die is clamped. After manual reposition of bone fragments 3 cm below the line of the knee joint, also along the anteromedial surface of the tibia perpendicular to the tibia, an incision-prick is made, a trocar is inserted to the bone, a stylet is removed from it and a hole is drilled through a protective sleeve with a 3.5-mm drill, sometimes expanding the hole in the near cortical layer with a 4.5-mm drill. Then, a second Shants rod is inserted through both cortical layers of the bone, on which an 82-mm die is also used as a handle, secured to the base end of the rod by locking two nuts. After bicortical transosseous insertion of the Shants rod, the die is removed from it by loosening and unscrewing the nuts. Both Shants rods are secured to one rod. For greater rigidity of fixation, parafracture Shants rods are applied in a similar manner at a distance of about 3 cm from the fracture zone. For better reposition of bone fragments in three dimensions, a modular frame is often used, the technique of which is that two Schanz rods (para-articular and parafracture) are inserted into each of the two main bone fragments, which are attached to two rods and connected to each other using intermediate rod. Reposition of bone fragments is carried out under X-ray control after loosening the fixation units connecting the intermediate rod with the two main ones. If AVF is chosen as the final osteosynthesis, then it is better to replace the modular frame with 1-2 solid rods. In the case of using AVF as a preliminary method of fixation, after stabilization of the patient’s general condition, final intramedullary or external osteosynthesis is routinely performed.

Criticism of the prototype

However, along with the atraumatic nature of using a rod AVF, the method of manual transosseous insertion of Shants rods during its installation has the following disadvantages:

- the need for a special wrench for manual transosseous passage of the Shants rod, or the much more commonly practiced use of a die from the Ilizarov apparatus set as a cross-shaped handle, which is secured to the Shants rod by locking, i.e. counter-rotation of two nuts placed on the base end of the Shants rod on both sides of the die. After passing the Shants rod, reverse rotation of the nuts (unlocking) is performed and the die is removed;

- the need for rather labor-intensive efforts with two open-end wrenches both when blocking (locking) and when unlocking (unlocking) the Shants rod in the die;

- a significant increase in the duration of the surgical intervention, due to the laboriousness of installing and securing a die from the Ilizarov apparatus kit on the Shants rod each time when installing each of the rods by counter-rotating two nuts, since the locking must be rigid enough so that the Shants rod does not rotate in the hole of the die when it is manually transosseous conduction, especially when passing through the second cortical layer of the bone, when the resistance to screwing doubles;

- frequent deformation and even breakage of the threads on the base end of the Shants rod or on counter-screwed nuts due to the need for rigid locking in order to avoid scrolling of the Shants rod in the hole of the die during its manual transosseous passage, especially when passing through the second cortical layer of the bone. In addition to being labor-intensive and time-consuming, this accelerates the wear of Schanz rods, made of special strong, inert and lightweight titanium alloys;

- the need to apply fairly noticeable manual pressure along the axis of the Shants rod in the process of screwing it into the bone along a drilled canal, - especially at the beginning of transosseous insertion of the rod through the first cortical plate of the bone, when the thread in the bone canal has not yet been formed by the threads of the Shants rod - causes a decrease in the precision accuracy of retention correct direction of the rod screwed into the bone. This, firstly, makes it difficult to pass the Schanz rod, secondly, it can cause it to deviate to the side from the drilled channel with its tip resting on the second cortical plate of the bone past the channel drilled in it, and thirdly, it often causes marginal damage bone around the drilled hole of the first cortical plate, reducing the strength of the metal-bone contact between it and the threaded part of the Schanz rod and the stability of fixation of both the Schanz rod and the entire AVF system.

The purpose of the invention is to increase the effectiveness of treatment of patients with high-energy fractures of long tubular bones of the extremities in the acute period of polytrauma, requiring installation of a rod AVF.

The essence of the invention

A device is proposed (Fig. 1) for mechanical transosseous insertion of Shants rods (item 1), which is a nozzle, characterized in that it is made of a threaded rod (item 2), a high nut (item 3) and nuts (item 4) from the Ilizarov apparatus set and serves as a transmission link (Fig. 2a) between the Shants rod (item 1), the base end of which is secured in the device by screwing into a high nut (item 3) and counter-rotating (locking) the nut (item .4) and a high nut (item 3), and (Fig. 2, b) an electric drill, in the chuck of which (item 5) the free end of its threaded rod (item 2) is secured and the work of which is used to mechanically insert the Shants rod ( pos. 1) into the bone when installing the AVF, as well as its reverse removal from the bone by reverse rotation of the drill chuck (pos. 5) when dismantling the AVF.

This device is used as follows. When a patient is admitted with polytrauma, which includes a diaphyseal fracture of the long bones of the extremities, for example, the femur, after manual reduction of the fracture along the lateral surface of the femur 3-4 cm above the lateral condyle of the femur, a sharp-pointed scalpel is used to incise the skin perpendicular to the femur up to 1 cm A trocar is inserted into this short incision with an emphasis on the bone, the stylet is removed from it, and both cortical layers of the femur are drilled through a protective sleeve with a 3.5 mm drill. Then, a pre-assembled device for mechanical insertion of the Shants rod is fixed in the drill chuck - an attachment from parts of the Ilizarov apparatus kit, consisting of a 65 mm threaded rod (item 2), a high nut (item 3) and two nuts (item 4), and in which the base end of the Shants rod (pos. 1) is installed, secured in the nozzle by screwing it into a high nut (pos. 3) and counter-rotating (locking) the nut (pos. 4) and the high nut (pos. 3). After mechanical bicortical insertion of the Shants rod (item 1), this device is disconnected from the drill chuck (item 5), and the Shants rod (item 1) is disconnected from this device by unlocking (reverse rotation) the high nut (item 3) and the nut (pos. 4) on the Shants rod (pos. 1) and unscrewing from the high nut (pos. 3). Then, also along the outer surface of the thigh, 5-6 cm below the base of the greater trochanter, a second Shants rod (item 1) is inserted, sequentially alternating in a drill chuck (item 5) a 3.5 mm drill and a device for mechanical transosseous insertion of Shants rods with with a Shants rod installed in it. In the same way as the installed paraarticular rods, two parafracture rods of Shants are mechanically carried out bicortically and installed, placing them 3-5 cm on both sides of the fracture line. All four bicortically inserted Shants rods (item 1) are connected by a common external frame. In this case, the fracture is stabilized, and the time required is minimal.

It should be noted that the device for mechanical transosseous conduction of Shants rods (Fig. 1) is in a pre-assembled form with a high nut (item 3) and a nut (item 4) firmly locked on the threaded rod (item 2). In addition to considerations of saving intraoperative time, this is dictated by the fact that the free end of the threaded rod (item 2) is fixed each time in the drill chuck (item 5), and it is no longer intended for screwing nuts (item 4) or a high nut onto it (position 3) due to the fact that fastening the end of the threaded rod (position 2) in the drill chuck (position 5) usually deforms its thread, making it unsuitable for freely screwing nuts or a high nut. The same circumstance determines the inadmissibility of mechanical transosseous insertion of Shants rods directly without an attachment, with their base end clamped in a drill chuck.

Device application example

As an example of the application of the proposed device, we present the following observation.

Patient M., 34 years old, was urgently taken to the Republican Center for Traumatology and Orthopedics (RCTO) in Makhachkala from the scene of an accident by passing transport on 03/04/2023 with a diagnosis of combined injury. I degree brain contusion. Fracture of II-III-IV-V-VI ribs on the right; right lung rupture; hemopneumothorax. Blunt abdominal trauma. Closed comminuted fracture of the right clavicle. Diaphyseal fracture of both bones of both legs: on the right - an open comminuted fracture at the level of the middle third of the leg (42-VZ, GA-I) and on the left - a closed oblique fracture at the border of the middle and lower third of the leg (42-B2) with displacement of fragments. Traumatic shock II-III degree.

Against the background of intensive infusion-transfusion therapy under endotracheal anesthesia, an operation was performed: Thoracentesis according to Bulau on the right with drainage of the right half of the chest. Abdominal laparocentesis (no blood obtained). Primary osteosynthesis of both tibial bones with two rod unilateral single-plane AVFs. The operation of installing the AVF was performed sequentially on both legs as follows.

After treating the skin of both lower extremities with antiseptic solutions and covering them with sterile linen, the visible displacement of the fracture was manually removed on the left shin. Then, 3 cm above the line of the ankle joint on the anteromedial surface of the leg perpendicular to the tibia, a skin incision 0.7-0.8 cm long was made, into which a trocar was inserted with an emphasis on the bone, a stylet was removed and, using a protective sleeve, perpendicular to the tibia A 3.5-mm drill was used to drill a hole in it through both cortical layers. A Shants rod was inserted bicortically into the formed bone canal using a device for mechanical transosseous insertion of rods, which is a nozzle made of a 65-mm threaded rod, a high nut and nuts from the Ilizarov apparatus set. This device was assembled in advance - with a high nut and a nut firmly locked on the threaded rod - which was dictated, in addition to considerations of saving time during the operation, by the fact that when carrying out each of the Shants rods, the free end of the threaded rod was each time fixed in the drill chuck and was no longer intended for screwing nuts or a tall nut onto it, because. fastening the end of a threaded rod in a drill chuck often deforms its thread, making it unsuitable for screwing. This device served as a transmission link between the Shants rod, the base end of which was secured in the device by screwing it into a high nut and locking the nut and the high nut, and an electric drill (screwdriver), in the chuck of which the free end of the threaded rod of the device was secured. Using the tip of the Shants rod, inserted into the notch wound, they felt a hole in the first cortical layer of the tibia and, giving the correct direction to the Shants rod, corresponding to the transosseous drilled channel, with light pressure along the axis of the rod with the nozzle, they pulled the trigger of a drill operating at low speeds. In this case, the Shantz rod was mechanically passed through both cortical layers of the tibia with the tip of the rod extending beyond the surface of the second cortical plate of the bone by 0.3-0.5 cm, which was judged not only by the depth of immersion of the rod into the wound and into the bone, but and by doubling the resistance to twisting when passing the Schanz rod through the second cortical plate. After bicortical mechanical insertion of the Shants rod, the attachment device was disconnected from the drill by loosening the clamp of its chuck, and from the Shants rod inserted into the bone by unlocking (reverse rotation) the high nut and the nut on the Shants rod and unscrewing the rod from the high nut. Similarly to the first, the second para-articular rod (3-4 cm below the line of the knee joint) and both parafracture rods of Shants (3-5 cm on both sides of the fracture line) were inserted, sequentially alternating a 3.5-mm drill in the drill chuck and a device for mechanical transosseous insertion of Shants rods with another rod installed in it. All four bicortically inserted Shants rods were connected by a unilateral single-plane frame - one common rod.

A similar osteosynthesis with unilateral single-plane AVF was also performed on the right shin. The fractures on both sides were stabilized in a total of approximately 30 minutes.

Subsequently, after relief of shifts in homeostasis and stabilization of the patient’s general condition, on March 10, 2023, the following operation was performed: External osteosynthesis of the right clavicle with a plate with angular stability; dismantling of the AVF on the left tibia and intramedullary osteosynthesis of the left tibia with a locking rod.

On March 16, 2023, a similar operation was performed on the right leg, where the AVF was also converted into intramedullary osteosynthesis of the tibia. The postoperative period proceeded without complications, the wounds healed initially. The patient was discharged for outpatient treatment on March 21, 2023. The result of treatment was assessed by us as good.

Features of the invention that are different from the prototype

The design features (distinctive features from the prototype) of the device for mechanical transosseous insertion of Shants rods are the following (Figs. 1 and 2):

- the device consists of parts of a standard Ilizarov apparatus kit, namely: a threaded rod (item 2), a high nut (item 3) and nuts (item 4) from the Ilizarov apparatus kit;

- the device is a nozzle for securing Shants rods in it (item 1);

- the device serves as a transmission link between the Shants rod (item 1), the base end of which is secured in the device by screwing into a high nut (item 3) and counter-rotation of the nut (item 4) and the high nut (item 3), and an electric drill, in the cartridge of which (pos. 5) the free end of its threaded rod (pos. 2) is fixed;

- the device provides mechanical insertion of the Shants rod (pos. 1) into the bone using a drill, as well as its reverse removal from the bone by reverse rotation of the drill chuck (pos. 5);

- the device is in a pre-assembled form with a high nut (item 3) and a nut (item 4) firmly locked on the threaded rod (item 2), which, in addition to considerations of saving intraoperative time, is dictated by the fact that the free end of the threaded rod ( pos. 2) is fixed in the drill chuck (pos. 5) each time, and it is no longer intended for screwing nuts (pos. 4) or a high nut (pos. 3) onto it due to the fact that the fastener of the end of the threaded rod ( pos. 2) in the drill chuck (pos. 5) usually deforms its thread, making it unsuitable for screwing.

The technical result (advantages over the prototype) of the device for mechanical transosseous insertion of Shants rods are as follows:

- cost-effectiveness, speed and ease of manufacturing of the device, parts for which from the Ilizarov apparatus kit are usually available in any orthopedic and traumatology department;

- the device provides a simple, quick and reliable connection with the Shants rod and with the drill chuck, and their separation, which significantly reduces the time of use of the device and the duration of the entire surgical intervention;

- compactness of the device, comfort, high efficiency, ergonomics and a significant reduction in the labor intensity of both installation and dismantling of the AVF, due to the speed and ease of fastening the Shants rods in the device and the mechanical operation of the drill;

- a relatively large dosage of the required pressure along the axis of the Shants rod, necessary for screwing it into the bone;

- precision accuracy of insertion of the Schanz rod into the canal formed for it by reducing the backlash during its transosseous insertion, due to the uniform rotation of the rotating drill chuck, which, firstly, facilitates the initial insertion into the first cortical plate of the bone, and secondly, minimizes the risk deviation of the given direction of the Shants rod and, thirdly, increases the correspondence of the thread profile of the Shants rod and the formed thread of the bone canal with more dense contact at the metal-bone boundary and increased stability of the intraosseous fixation of the Shants rods and the entire AVF system;

- compliance of the use of the device with the combination of the “golden hour” rule (with the need for urgent anti-shock measures) and the concept of “Domage controb” (with atraumatic installation of AVF);

- reusability of the device, which does not lose its performance properties from long-term use;

- cost-effectiveness and increased service life of Schanz rods, due to the fact that not only the thread, but also the end surface of the base end of the Schanz rod installed in the device resists the thrust into the bone required during insertion, which makes this pressure more rational and better preserves the thread of the Schanz rod from deformation and rapid wear.

Thus, the proposed device makes it possible to improve the quality and speed of use of rod AVFs and create optimal conditions for increasing the effectiveness of treatment of patients to whom it is used, especially in conditions of polytrauma.

Claims (1)

A device for mechanical transosseous insertion of Shants rods, made in the form of a nozzle, characterized in that it contains a threaded rod, a high nut and two nuts from the Ilizarov apparatus set, and the high nut is locked at one end of the threaded rod using one nut from the Ilizarov apparatus set and is designed for screwing the end of the Shants rod into it and then fixing it by counter-rotating another nut from the Ilizarov apparatus set and a high nut, and the free end of the threaded rod is intended for fixing it in the electric drill chuck.

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