RU101909U1 - TRANSPEDICULAR SCREW DEVICE - Google Patents

Abstract

 The transpedicular screw device, characterized in that the length of the threaded massive part of the selected device size is increased by one third of the total screw body length.

Description

The utility model relates to the field of medical equipment for use in the field of orthopedics and traumatology.

In the past decade, the method of transpedicular osteosynthesis has been widely used in traumatology. However, when using this method, a number of complications arise, of which fractures of transpedicular screws are most often recorded [V.V.Usikov, V.D.Usikov. Errors and complications of transpedicular osteosynthesis in the treatment of patients with unstable spinal injuries, their prevention and treatment. - Traumatology and orthopedics of Russia. - 2006. - No. 1 (39), p.21-26.]. According to KS Sergeev, A.O. Farion, the frequency of fractures of transpedicular screws occur in 18-20% [Farion A.O. Stabilizing and decompression-stabilizing operations using transpedicular osteosynthesis in unstable fractures of the lower thoracic and lumbar vertebrae: Aftoref. dis ... cand. honey. sciences. - Kurgan, 2006. - p.3-17].

Known transpedicular screw [Patent RU No. 2242188, published 20.12.04., Bull. No. 35.], Having a head, a screw body, which consists of threaded and massive (threadless) parts. The disadvantages of this device include its low strength properties.

As a prototype, a transpedicular screw from BIOMET COMPANY was selected (Fig. 1). Representing an integral design consisting of a head, a screw body, threaded and massive (threadless) parts of the screw body. This device has insufficient strength in the screw body.

The objective of this device is to increase the strength of transpedicular screws and the exclusion of the possibility of their fracture.

The technical result is simple, not requiring large material costs, achieved by increasing the length of the massive (threadless) part of the screw.

The technical result is achieved by increasing the length of the massive (threadless) part of the screw by 1/3 of the total length of the screw body.

Depending on the anatomical structural features of the musculoskeletal system, transpedicular screws of various lengths (from 350 to 700 mm) and diameter (from 4.0 to 7.0 mm, table 1) were tested. Table 2 presents the dimensions of the massive (threadless) part of the transpedicular screw of the proposed device.

The theoretical justification for solving the problem. Maximum stresses in the transpedicular screw occur at the implant-bone interface. Based on our research in the field of dynamic mechanical testing, it was found that the fracture area of the transpedicular screws was 1-1.5 cm from the screw head (result of 15 tests). Figure 2 presents the fracture zone of the transpedicular screw, where 5 is the fracture zone; 1 - threaded part of the screw; 2 - massive (threadless) part of the screw; 3 - screw head; 4 - a nut; 6 - longitudinal rods designed to connect screws and fix adjacent vertebrae; 7 - transverse beam, designed for additional fixation of longitudinal rods.

The essence of the proposed device is illustrated by the graphic material shown in figure 3. The device consists of a threaded (1) and a threaded massive (2) parts that are inserted through the legs of the arches into the vertebral bodies. The head (3) of the device is designed to insert a screw and connect to the longitudinal rods, and the nut (4) is used to fix the longitudinal rods.

Practical examples

Example 1

A 55-year-old patient S. was admitted to the traumatology and orthopedic department of the Design Bureau No. 2 of Tyumen with a diagnosis of Closed compression-comminuted unstable not complicated fracture of the body of the L _III vertebra. After preoperative preparation and preoperative planning, an operation was performed: transpedicular fixation of L _II- L _IV vertebrae with the proposed device. Four transpedicular screws were selected: two with a diameter of 5.5 mm and a length of 500 mm .; the second two screws with a diameter of 6.0 mm and a length of 550 mm. The length of the massive (threadless) part of the used screws was 167 and 183 mm, respectively. The patient in a position on the abdomen has access to the posterior structures of the spinal column, then the pedicle screws are inserted and the pedicle system is installed. The operation is completed by drainage and suturing of the wound. The patient began work 6 months after the operation.

Example 2

A 23-year-old patient M. was admitted to the traumatology and orthopedic department of the Design Bureau No. 2 of Tyumen with a diagnosis of Closed complicated compression-comminuted unstable fracture of the body of the L _I vertebra. After preoperative preparation and preoperative planning, an operation was performed: laminectomy L _I transpedicular fixation of Th _XII- L _II vertebrae by the proposed device. Four transpedicular screws were selected: two - with a diameter of 4.5 mm and a length of 400 mm; the diameter of the second two screws was 5.0 mm with a length of 450 mm. The length of the massive (threadless) part of the screws was 133 and 150 mm, respectively. The patient in the position on the abdomen had access to the posterior structures of the spinal column, after laminectomy L _I , the introduction of transpedicular screws and installation of the transpedicular system were performed.

In the postoperative period, a regression of neurological symptoms was noted. The patient began work 11 months after the operation.

Example 3

A 58-year-old patient A. was admitted to the traumatology and orthopedic department of Tyumen Design Bureau No. 2 with a diagnosis of Closed compression-comminuted unstable uncomplicated fracture of the L _II vertebral body, compression fracture of the L _I vertebral body, against osteoporosis. After preoperative preparation and preoperative planning, an operation was performed: transpedicular fixation of Th _XII -L _I -L _III vertebrae by the proposed device. Six transpedicular screws were selected, two with a diameter of 4.5 mm and a length of 400 mm; two - with a diameter of 5.0 mm and a length of 450 mm; two - with a diameter of 5.5 mm and a length of 500 mm. The length of the massive (threadless) part of the screws was 133, 150 and 167 mm, respectively. The patient in a position on the abdomen had access to the posterior structures of the spinal column, then the pedicle screws were inserted and the transpedicular system was installed. The operation ended with drainage and suturing of the wound. The patient was discharged in satisfactory condition.

The given examples illustrate the possibility of an isolated application of the device for stabilization of the spine without additional stabilizing operations. The device was implemented on the basis of the Tyumen Design Bureau No. 2, GLPUTOOB No. 3, Tobolsk. Using this device, 26 operations were performed.

Evaluation of the economic and positive effect of the proposed device is carried out in comparison with the prototype and is presented in table 3. The economic efficiency of the device compared to the prototype was 18,000-54,000 thousand rubles, depending on the number of transpedicular screws used during the operation.

Table 1 Dimensions of transpedicular screws used according to the proposed device Diameter (in mm) Screw length (in mm) Diameter (in mm) Screw length (in mm) Diameter (in mm) Screw length (in mm) 4.0 350 4.5 350 5,0 350 4.0 400 4.5 400 5,0 400 4.0 450 4.5 450 5,0 450 4.0 500 4.5 500 5,0 500 4.0 550 4.5 550 5,0 550 4.0 600 4.5 600 5,0 600 4.0 650 4.5 650 5,0 650 4.0 700 4.5 700 5,0 700 Diameter (in mm) Screw length (in mm) Diameter (in mm) Screw length (in mm) Diameter (in mm) Screw length (in mm) 5.5 350 6.0 350 6.5 350 5.5 400 6.0 400 6.5 400 5.5 450 6.0 450 6.5 450 5.5 500 6.0 500 6.5 500 5.5 550 6.0 550 6.5 550 5.5 600 6.0 600 6.5 600 5.5 650 6.0 650 6.5 650 5.5 700 6.0 700 6.5 700 Diameter (in mm) Screw length (in mm) 7.0 350 7.0 400 7.0 450 7.0 500 7.0 550 7.0 600 7.0 650 7.0 700 table 2 The length of the massive part of the transpedicular screw in the proposed device Screw length (in mm) The length of the massive part of the screw (in mm) 350 117 400 133 450 150 500 167 550 183 600 200 650 217 700 233

Table 3 Assessment of the positive and economic effect compared to the prototype Sign Prototype Device The cost of one transpedicular screw 6500 rubles 2000 rubles Traumatism Moderate Minimum Minimally invasive surgery Impossible Available The use of additional stabilizing operations Are needed Are excluded Revision Surgery Are possible Not carried out Fractures in the rehabilitation period Are possible Not observed

Claims (1)

The transpedicular screw device, characterized in that the length of the threaded massive part of the selected device size is increased by one third of the total screw body length.