Bioresorbable screw

Abstract

The utility model relates to medicine, in particular to traumatology, orthopedics and maxillofacial surgery, and can be used for fixation of bone fragments in fractures, reconstructive surgeries and osteosynthesis of the bones of the facial skeleton and extremities. The technical result consists in increasing the strength of fixation of bone fragments. The said technical result is achieved in that the bioresorbable screw, comprising a cylindrical head and a screw body with an external thread, has a triangular cutting thread profile, a groove for a tool is made in the end of the head, according to the solution, a support platform is formed between the head and the screw body; cutting grooves are made in the apical part of the screw body, forming a self-tapping tip; the profile of the cutting grooves has a trapezoidal shape. 3 c.p. phyl., 4 fig.

Description

[0001] Technical field

[0002] The utility model relates to medicine, in particular to traumatology, orthopedics and maxillofacial surgery, and can be used for fixing bone fragments in fractures, reconstructive surgeries and osteosynthesis of the bones of the facial skeleton and limbs.

[0003] Technology Level

[0004] A known screw for maxillofacial surgery and surgical dentistry is known from the level (see patent RU 187498, IPC A61C 8 / 00, published 11.03.2019), comprising a head with a groove for a screwdriver and a working part with threads, made of a titanium-containing alloy. The screw additionally contains a smooth polished part between the head and the working part with threads, with an overall screw length of 3.3-8 mm and a cap thickness of 0.4-0.6 mm, the thread diameter is 1.2-1.8 mm with a thread pitch of 0.6-0.9 and a cap width of 2.5-5.0 mm, and a leg length of 3.1-6.8, while the groove for a screwdriver is made cross-shaped, and the leg passes into the head at a right angle.

[0005] A dental screw for fixing bone tissue is known (see patent RU 238381, IPC A61C 8 / 00, published 28.10.2025), designed as a rod with a rounded head. The head is designed as a disk with a screw rotation element, with holes evenly distributed around the head circumference, and the tip of the rod is threaded, with the screw rotation element being a cross-shaped recess in the head.

[0006] A bioresorbable screw is known (see patent RU 2782108, IPC A61F 2 / 28, A61B 17 / 86, A61C 8 / 00, published 21.10.2022), containing a thread for screwing into a bone, a head having a cap and a drive part, wherein the cap contains a substantially flat contact surface for the implant, and between the drive part and the cap there is a predetermined fracture point, which is made in the form of a narrowing between the upper side of the cap and the drive part, wherein the screw rod increases in thickness in the direction of the cap, the thread is made so that the thread teeth are made flat or rounded on the outside, and the base of the tooth with a rounding passes into the lateral surfaces of the tooth.

[0007] The closest comparable device to the claimed device is an orthodontic mini-screw (see patent RU 221591, IPC A61C 8 / 00, published 11 / 13 / 2023), comprising a cylindrical head and a mini-screw body, the lower portion of which is provided with an external thread. The thread profile at the tip is triangular in shape, and towards the upper portion, the thread profile transitions to a trapezoidal cross-section, aligning with the body of the mini-screw. The upper portion of the head is provided with an annular cutout, and the end of the head has an internal triangular hole for a socket wrench.

[0008] However, the above devices provide weak fixation of bone fragments.

[0009] Disclosure of the essence of the utility model

[0010] The technical problem is to develop a bioresorbable self-tapping screw that provides reliable fixation of bone fragments without the need for repeated surgical removal of the structure.

[0011] The technical result consists in increasing the strength of fixation of bone fragments.

[0012] The stated technical result is achieved by a bioresorbable screw comprising a cylindrical head and a screw body with an external thread, the thread profile of which is made triangular cutting, a groove for a tool is formed in the end of the head, according to the solution, a support platform is formed between the head and the screw body; cutting grooves are formed in the apical part of the screw body, forming a self-tapping tip; the profile of the cutting grooves is trapezoidal.

[0013] The groove is made in a star or cross shape.

[0014] The screw is made by thermoplastic molding from a bioresorbable polymer material based on polylactic acid, or polyglycolide, or their copolymers.

[0015] Brief description of drawings

[0016] The utility model is explained by drawings, where Fig. 1 shows a general view of the claimed device, Fig. 2 shows a longitudinal section (A-A) of the claimed device, Fig. 3 shows a screw head (top view), Fig. 4 shows a cross-section of a screw head (B-B).

[0017] The following positions are indicated on the figures: 1 - screw head; 2 - groove; 3 - support platform; 4 - threaded part of the screw; 5 - cutting edges of the thread; 6 - spiral thread profile; 7 - cutting grooves in the apical part; 8 - self-tapping tip.

[0018] Implementation of a utility model

[0019] The bioresorbable screw comprises a cylindrical head 1 and a screw body with external thread 4 (Figs. 1, 2). The thread profile is made with a triangular cutting profile. A groove 2 for an instrument is made in the end of the head 1 (Figs. 3, 4). A support platform 3 is formed between the head 1 and the screw body. In the apical part of the screw body, cutting grooves 7 are made, forming a self-tapping tip 8. The profile of the cutting grooves 7 has a trapezoidal shape.

[0020] Screw head 1 provides support for the instrument and transmits torque. Groove (slotted drive) 2 has a star or cross shape. The groove ensures reliable interaction with the instrument and reduces the risk of slippage. Support pad 3 ensures tight adherence of the fixed membrane or tissue to the bone surface. The threaded portion of the screw 4 ensures secure fixation in the bone tissue. The cutting edges of the thread 5 form a threaded channel in the bone tissue during screw insertion. The helical profile of the thread 6 reduces torque and ensures uniform load distribution. Cutting grooves in the apical portion 7 ensure self-tapping when passing through the cortical plate and reduce the risk of bone fracture. The self-tapping tip with a pointed shape 8 facilitates screw insertion and centering at the installation point.

[0021] The screw is made by thermoplastic molding from a bioresorbable polymer material based on polylactic acid, polyglycolide or their copolymers, which are biocompatible and capable of gradual hydrolytic breakdown in body tissues.

[0022] The threaded part of the screw is designed with the ability to independently form a thread in the bone tissue when the screw is inserted without the use of an additional tap.

[0023] The device operates as follows.

[0024] After the bone fragments are repositioned, a guide channel of the appropriate diameter is created in the bone tissue. A screw is then inserted into the prepared channel using a surgical screwdriver. As the screw rotates, its self-tapping end forms a thread in the bone tissue, and the threaded portion ensures a tight connection and compression of the bone fragments. This ensures stable fixation of the fracture site or bone defect.

[0025] During the postoperative period, the screw maintains the mechanical strength necessary for primary bone tissue healing. As the bone regenerates, the screw material gradually undergoes hydrolytic biodegradation, forming biocompatible breakdown products that are naturally metabolized by the body.

[0026] After the bone tissue regeneration processes are completed, the screw is completely or partially resorbed, which eliminates the need for repeated surgical intervention to remove the fixing structure.

[0027] Example.

[0028] A patient with a maxillary alveolar bone defect undergoes guided bone regeneration surgery. After local anesthesia, a mucoperiosteal flap is created and the surgical site is prepared. Bone grafting material and a resorbable barrier membrane are placed in the bone defect. The membrane is secured with the device described in the invention. A pilot hole with a diameter smaller than the outer diameter of the screw thread is made in the cortical plate. The screw is inserted directly into the bone using a rotary motion using a dental screwdriver.

[0029] When the screw is inserted, the cutting grooves and self-tapping profile of the apical portion create a thread in the bone tissue without the need for an additional tap. The thread design ensures gradual load distribution as it penetrates the cortical plate, achieving primary fixation stability. Once the required insertion depth is reached, the membrane and bone grafting material are firmly fixed to the bone surface. The postoperative wound is sutured.

[0030] In the postoperative period, the screw maintains mechanical stability throughout the period of bone tissue regeneration, after which it gradually undergoes biodegradation and resorption without the need for repeated surgical intervention to remove the product.

Claims

1. A bioresorbable screw comprising a cylindrical head and a screw body with external threads, the thread profile being triangular in shape and cutting, with a groove for a tool formed in the end of the head, characterized in that a support surface is formed between the head and the screw body; cutting grooves are formed in the apical portion of the screw body, forming a self-tapping tip; the profile of the cutting grooves is trapezoidal.

2. A screw according to item 1, characterized in that the groove is star-shaped.

3. A screw according to item 1, characterized in that the groove is made in a cross-shaped form.

4. A screw according to claim 1, characterized in that it is manufactured by thermoplastic molding from a bioresorbable polymer material based on polylactic acid or polyglycolide or their copolymers.

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