Device for fixing and restoring skull flap

Abstract

The utility model discloses a device for fixing and restoring skull bone flaps, and belongs to the technical field of bone fixing and repairing. The device comprises a skull fixator, the skull fixator comprises a skull side fixing end and a bone flap side fixing end which are fixedly connected, and the skull side fixing end is fixed to a skull through a fixing titanium nail; an adjusting boss with an internal thread is arranged on the bone flap side fixing end, the first titanium nail sequentially penetrates through the defective bone flap and the lifting structure and then is connected with the internal thread of the adjusting boss in a matched mode, and the defective bone flap and the bone flap side fixing end are fixed together. A new choice is provided for pure complete fixation and bone flap removal after the craniocerebral operation, the problem that the intracranial pressure is increased after pure skull fixation can be effectively solved, the risk caused by brain tissue swelling after the operation is reduced, and meanwhile the stability after bone flap reduction can be guaranteed.

Description

Technical Field

[0001] This utility model relates to the field of bone fixation and repair technology, specifically to a device for fixing and repositioning cranial bone flaps. Background Technology

[0002] In the field of bone fixation and repair, including neurosurgery, maxillofacial surgery, cardiothoracic surgery, and orthopedics, procedures such as craniotomy in neurosurgery involve the repositioning and fixation of the skull postoperatively. Originally, skull fixation primarily relied on sutures. Gradually, a method called skull locking fixation emerged, using two metal discs to lock the skull from both inside and outside the skull for fixation. However, this method carries the risk of postoperative epidural hematoma. Later, skull fixation employed bone connector fixation, where a free bone flap is fixed to the surrounding bone margin using bone screws and bone connectors. This typically involves using a manual screwdriver to first fix at least three connectors to the free bone flap with screws, then repositioning the skull, and finally using a manual screwdriver to fix the other end of the connector to the surrounding bone margin. After decades of development, the primary method currently remains the use of titanium alloy bone connectors, fixed internally to the bone tissue with screws.

[0003] Traditional fixation methods, while preserving the bone flap and skull structure, fail to achieve decompression. Around age 1.5, the cranial sutures typically close, transforming the cranial cavity into a closed, relatively fixed "large container." This "large container" primarily comprises brain tissue (1400g), cerebrospinal fluid (75ml), and blood (75ml). Under normal circumstances, the total volume of these three components maintains a dynamic balance with the total volume of the "large container," keeping intracranial pressure at a normal level. Because brain tissue volume is relatively constant, especially during acute intracranial hypertension, it cannot be compressed. Therefore, intracranial pressure is regulated by maintaining a balance between cerebral blood volume and cerebrospinal fluid volume. Cerebrospinal fluid is the most variable component, with approximately 75ml in the ventricles, cisterns, and subarachnoid space, accounting for about 5.5% of the cranial cavity volume. When intracranial hypertension occurs, the body first reduces cerebrospinal fluid secretion, increases absorption, and partially compresses it out of the skull to alleviate the increased intracranial pressure, subsequently compressing cerebral blood volume. Therefore, the compensatory volume available to relieve intracranial hypertension is approximately 8% of the cranial cavity volume. Thus, when pathological conditions such as cerebral hemorrhage, extensive cerebral contusion, severe cerebral edema, large-area cerebral infarction, diffuse cerebral edema, or brain tumors increase in volume beyond the compensatory volume of the cranial cavity, intracranial hypertension can occur. A continuous increase in intracranial pressure can impair the regulation of cerebral blood flow, leading to severe cerebral ischemia and hypoxia, exacerbating cerebral edema, increasing brain tissue volume, and further raising intracranial pressure. This can cause brain tissue displacement, resulting in brain herniation, ultimately leading to brainstem compression, respiratory and circulatory center failure, and death.

[0004] In clinical practice, decompressive craniectomy is performed for patients with severe intracranial pressure, while cranioplasty is performed for patients with milder conditions such as unruptured aneurysms. Maintaining normal intracranial pressure early on and reducing complications caused by high intracranial pressure are crucial for improving postoperative prognosis. However, for patients suspected of having delayed intracranial pressure after intracranial surgery, there is no device that can guarantee the stability of the normal skull repositioning structure while achieving primary decompression. The decision to retain or remove the bone flap is usually made by the surgeon based on the patient's actual condition and intraoperative findings. Among patients who retain the bone flap, there are those whose prognosis has declined due to increased intracranial pressure postoperatively, sometimes even requiring secondary surgery. Performing secondary cranioplasty after decompressive craniectomy not only causes secondary trauma and increases the risks of infection and anesthesia, but also places a heavier financial burden on the patient.

[0005] In summary, traditional cranioplasty systems can only reduce and fix bone flaps. Since there is no third option, surgeons often remove bone flaps to ensure patient safety. In patients who retain bone flaps, brain tissue may be restricted by the bone flaps during the recovery process of cerebral edema, thus affecting the prognosis. Utility Model Content

[0006] The purpose of this invention is to provide a device for fixing and reducing cranial bone flaps. This device can not only completely replace traditional simple fixation devices, but also reduce the adverse consequences caused by intracranial pressure after surgery, and stabilize intracranial pressure without the need for a second surgery.

[0007] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0008] A device for fixing and reducing a cranial bone flap includes a cranial fixator and a defective bone flap. The cranial fixator is used to fix the defective bone flap to the skull. The cranial fixator includes a cranial side fixation end, a first titanium screw, a lifting structure, an adjusting boss, a bone flap side fixation end, and a fixing titanium screw. The adjusting boss is a cylindrical structure with internal threads. The lifting structure is a spring made of medical-grade stainless steel or titanium alloy, which is placed between the defective bone flap and the adjusting boss. The cranial side fixation end is fixedly connected to the bone flap side fixation end. The cranial side fixation end is fixed to the skull by the fixing titanium screw. The adjusting boss is disposed on the bone flap side fixation end. The first titanium screw passes through the defective bone flap and the lifting structure in sequence and is screwed together with the adjusting boss, thereby fixing the defective bone flap to the bone flap side fixation end.

[0009] Furthermore, the cranial side fixation end is a semi-cylindrical structure with a radius of 5 mm, and a cranial fixation hole is provided in its center. The fixing titanium nail fixes the cranial side fixation end to the skull through the fixing hole. The arc-shaped surface of the cranial side fixation end faces the skull side, and a semi-cylindrical through groove adapted to it is opened at the corresponding position of the skull. The cranial side fixation end is embedded in the through groove and then fixed by the fixing titanium nail. The fixing titanium nail extends out of the cranial side fixation end and is fixed into the skull.

[0010] Furthermore, the fixation end on the bone flap side has a scale-like structure and an adjustment boss is provided at its center; the first titanium nail fixes the fixation end on the bone flap side to the defective bone flap by screwing it into the adjustment boss.

[0011] Furthermore, the number of cranial fixators is 3-6, preferably 3, and they are installed in a three-point (triangle) or multi-point symmetrical manner. This can be dynamically adjusted according to the patient's condition to meet the needs of different patients.

[0012] Furthermore, the skull-side fixation end is a semi-cylindrical structure with a radius of 5 mm; the bone flap-side fixation end is a scale-like structure with a length of 10 mm and a width of 8 mm; the adjusting boss has an inner diameter of 3 mm, an outer diameter of 4 mm, and a height of 6 mm; the lifting structure is a spring with an inner diameter of 4.5 mm and a minimum compression length of 2 mm; the adjusting boss has a 6 mm limit to prevent damage to brain tissue caused by excessive tightening force or excessive rotation stroke of the first titanium nail.

[0013] Furthermore, the cylindrical end radius of the first titanium nail and the fixed titanium nail is 1.5 mm and the length is 8 mm; by adjusting the rotation of the first titanium nail (clockwise or counterclockwise) to achieve different degrees of compression and lifting structure, the defective bone flap can be raised or lowered; the maximum elevation is 6 mm, and the descent does not exceed the lowest point of the skull fixator.

[0014] Furthermore, the lifting structure can lift the bone defect by rotating the first titanium nail clockwise, using its elasticity; and by rotating the first titanium nail counterclockwise, it can compress the lifting structure to lower the bone defect, thereby reducing the distance between the bone defect and the skull; the diameter of the first titanium nail head should be larger than the diameter of the lifting structure; and the maximum elasticity of the lifting structure should be less than the maximum bearing capacity of the first titanium nail.

[0015] Furthermore, the cranial side fixation end, the first titanium nail, the lifting structure, the adjusting boss, the bone flap side fixation end, and the fixation titanium nail are all made of medical-grade titanium alloy.

[0016] The above-mentioned device is used for the fixation and reduction of cranial bone flaps. The method involves dynamically adjusting the cranial fixator according to the patient's physical condition, using three-point or multi-point symmetrical fixation, and fixing each cranial fixator to the defective bone flap and the skull respectively; then adjusting the first titanium screw to rotate clockwise or counterclockwise to drive the defective bone flap to rise or fall, thereby adjusting the distance between the defective bone flap and the skull.

[0017] The design principle and beneficial effects of this utility model patent are as follows:

[0018] 1. This utility model relates to a device for fixing and reducing skull bone flaps, and also to a device and method for pre-elevation fixation within the bone hole during craniocerebral surgery. It solves the problem of decompression in traditional skull fixation systems. Furthermore, this device is stronger than traditional plate-and-screw fixation systems and skull locking systems, ensuring stability after bone flap reduction. The device can elevate the defective bone flap by adjusting the first titanium screw, and can be reduced normally along the rotation path. It has a certain tension and is unaffected by gravity or other forces when intracranial pressure is normal. Considering the patient's skull thickness, a titanium mesh can be used to replace the skull for primary repair. Stable fixation is achieved after 3 months post-surgery with connective tissue encapsulation.

[0019] 2. This utility model device has improved fixation stability: Traditional nail systems use a three-point fixation method with a single titanium plate, while this utility model uses a three-point or multi-point symmetrical fixation method. Each device is fixed to the bone defect flap and skull respectively, resulting in greater stability. It is connected by a first titanium nail and a fixing titanium nail, making it stronger than traditional fixation systems.

[0020] 3. This utility model device has an adjustable lifting function, which can effectively reduce brain damage caused by increased intracranial pressure after surgery, enhance postoperative rehabilitation, and reduce intracranial pressure.

[0021] 4. This novel device effectively reduces the reliance on empirical judgment regarding bone flap retention or removal, providing a completely new option for postoperative patients and giving surgeons greater confidence in their treatment. For patients with intraoperative brain injury, this device can completely replace the traditional screw-and-plate system for craniotomy, reducing postoperative complications, increasing surgeon confidence, and lowering the difficulty of the procedure. It offers new options and approaches for most patients, placing them between bone flap surgery and minimally invasive surgery, and has a very positive effect on the treatment of brain injury patients.

[0022] 5. This utility model device allows for primary cranioplasty. In surgeries without infection risk, titanium mesh can replace primary cranioplasty, reducing the risk of postoperative intracranial hypertension and the associated risks and financial burden of secondary cranioplasty. For patients with mild to moderate postoperative cerebral edema, the device can elevate the skull by approximately 6 millimeters, effectively achieving decompression. Especially for patients with moderate cerebral edema, the decompression-enhancing bone flap combined with traditional dehydration therapy can provide the best prognosis, faster recovery, and better results without the need for bone flap removal. For patients in primary hospitals with minimal intraoperative cerebral edema but unable to determine the postoperative risk of cerebral edema, this utility model can replace traditional bone flaps, ensuring surgical efficacy.

[0023] 6. This invention can also be applied to patients with mild symptoms, achieving decompression at the earliest stage. It can also achieve early decompression for acute complications such as postoperative acute bleeding and drainage tube blockage, thus buying time for a second surgery and improving the patient's survival rate.

[0024] 7. The device of this utility model has a simple structure and controllable cost, which is conducive to practical application and promotion. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the installation of the device for fixing and repositioning cranial bone flaps according to this utility model.

[0026] Figure 2 This is a schematic diagram of the device for fixing and repositioning cranial bone flaps according to the present invention.

[0027] In the figure: 100-skull fixator, 101-skull side fixation end, 102-first titanium nail, 103-lifting structure, 104-adjusting boss, 105-bone flap side fixation end, 106-fixation titanium nail, 200-defect bone flap, 300-skull. Detailed Implementation

[0028] To further understand this utility model, it will be described in detail below.

[0029] This utility model provides a device for fixing and reducing skull bone flaps, such as... Figure 1 As shown. The device includes a cranial fixator 100 and a bone defect flap 200. The cranial fixator 100 is used to fix the bone defect flap 200 to the skull 300. The number of cranial fixators 100 is 3-6, preferably 3, and they are installed in a three-point (when there are 3) or multi-point symmetrical manner.

[0030] like Figure 2As shown, the cranial fixator 100 includes a cranial side fixation end 101, a first titanium nail 102, a lifting structure 103, an adjusting boss 104, a bone flap side fixation end 105, and a fixing titanium nail 106; the cranial side fixation end 101, the first titanium nail 102, the lifting structure 103, the adjusting boss 104, the bone flap side fixation end 105, and the fixing titanium nail 106 are all made of medical-grade titanium alloy.

[0031] The skull-side fixation end 101 is a semi-cylindrical structure with a radius of 5 mm and a skull fixation hole is opened at its center; the bone flap-side fixation end 105 is a scale-shaped structure and an adjustment boss 104 is provided at its center. The adjustment boss 104 is a cylindrical structure with internal threads.

[0032] The lifting structure 103 is a spring made of medical stainless steel or titanium alloy, which is sleeved on the first titanium nail 102 and placed between the defective bone flap 200 and the adjusting boss.

[0033] The lower end of the skull-side fixation end 101 is welded and fixed together with the thicker end of the bone flap-side fixation end 105; preferably, the angle between the axis (height direction) of the skull-side fixation end 101 and the length direction of the bone flap-side fixation end 105 is 60-120°. The bottom surface of the adjustment boss 104 is welded and fixed to the bone flap-side fixation end 105.

[0034] The skull-side fixation end 101 is fixed to the skull 300 by fixing titanium nails 106. Specifically, the arc-shaped surface of the skull-side fixation end faces the skull side, and a semi-cylindrical through groove adapted to it is opened at the corresponding position of the skull. After the skull-side fixation end is inserted into the semi-cylindrical through groove, the fixing titanium nail 106 passes through the skull fixation hole on the skull-side fixation end 101, extends out of the skull-side fixation end, and is fixed into the skull.

[0035] The bone flap-side fixing end 105 is fixed to the defective bone flap 200 by a first titanium nail 102. Specifically, the first titanium nail 102 passes through the defective bone flap 200 and the lifting structure 103 in sequence and is screwed into the adjusting boss 104 to fix the defective bone flap 200 and the bone flap-side fixing end 105 together.

[0036] The skull-side fixation end 101 is preferably a semi-cylindrical structure with a radius of 5 mm.

[0037] The fixation end 105 on the bone flap side is preferably a scale-like structure with a length of 10 mm and a width of 8 mm.

[0038] The adjusting boss 104 preferably has an inner diameter of 3 mm, an outer diameter of 4 mm, and a height of 6 mm; the adjusting boss 104 preferably has a 6 mm limit to prevent damage to brain tissue caused by excessive tightening force or excessive rotation stroke of the first titanium nail 102.

[0039] The lifting structure 103 is preferably a spring with an inner diameter of 4.5 mm and a minimum compression length of 2 mm;

[0040] The first titanium nail 102 and the fixing titanium nail 106 preferably have a cylindrical end radius of 1.5 mm and a length of 8 mm. Different degrees of compression and lifting of the structure 103 are achieved by adjusting the rotation of the first titanium nail 102, thereby raising or lowering the bone defect 200. For example, the lifting structure 103 can raise the bone defect 200 by rotating the first titanium nail 102 clockwise, using its elasticity; and lower the bone defect 200 by rotating the first titanium nail 102 counterclockwise, thereby reducing the distance between the bone defect 200 and the skull 300. The diameter of the first titanium nail 102 head should be larger than the diameter of the lifting structure 103. The maximum elasticity of the lifting structure 103 should be less than the maximum bearing capacity of the first titanium nail 102. The maximum lifting displacement is 6 mm, and the lowering displacement does not exceed the lowest point of the skull fixator 100.

[0041] When using this device for fixing and reducing skull bone flaps, three skull fixators are installed in a triangular positioning configuration to fix the defective bone flap 200 onto the skull 300. The number of fixators can be dynamically adjusted according to the patient's condition. For example, if the wound is large, the number of skull fixators 100 needs to be increased, such as selecting 4, 5, or 6, to meet the needs of different patients. Each skull fixator 100 is fixed to the defective bone flap and the skull respectively. Then, the first titanium screw is adjusted to rotate clockwise or counterclockwise to raise or lower the defective bone flap, thereby adjusting the distance between the defective bone flap and the skull.

[0042] This invention provides a new means and method for the reduction and fixation of bone flaps after craniocerebral surgery, offering a new option between simple complete fixation and bone flap removal. For patients considering the possibility of increased intracranial pressure postoperatively, this fixation device effectively addresses the issue of increased intracranial pressure after simple skull fixation, helping to control the risks associated with postoperative brain tissue swelling. Furthermore, this device is stronger than traditional screw-plate fixation systems and cranial locking systems, ensuring stability after bone flap reduction. The device allows for the elevation of the defective bone flap 200 by adjusting the first titanium screw 102, and can be reduced normally along the rotation path with a certain tension. A thinner titanium mesh can be used to replace the skull on the bone flap side. For non-open surgeries without significant infection, it achieves primary repair of the postoperative skull. After 3 months postoperatively, with connective tissue encapsulation, the effect is indistinguishable from existing cranial fixation systems on the market.

[0043] The above embodiments are only for illustrating the technical concept and features of this utility model, and are intended to enable those skilled in the art to understand the content of this utility model and implement it. They cannot be used to limit the protection scope of this utility model. All equivalent changes or modifications made based on the essence of this utility model shall fall within the protection scope of this utility model.

Claims

1. A device for fixing and reducing skull bone flaps, characterized in that: The device includes a cranial fixator (100) and a bone defect flap (200), the cranial fixator (100) being used to fix the bone defect flap (200) to the skull (300); The cranial fixator (100) includes a cranial side fixation end (101), a first titanium screw (102), a lifting structure (103), an adjusting boss (104), a bone flap side fixation end (105), and a fixing titanium screw (106); the adjusting boss (104) is a cylindrical structure with internal threads; the lifting structure (103) is a spring made of medical stainless steel or titanium alloy, which is placed between the defective bone flap (200) and the adjusting boss; The skull-side fixation end (101) is fixedly connected to the bone flap-side fixation end (105); the skull-side fixation end (101) is fixed to the skull (300) by a fixing titanium nail (106); the adjustment boss (104) is set on the bone flap-side fixation end (105), and the first titanium nail (102) passes through the defective bone flap (200) and the lifting structure (103) in sequence and is screwed together with the adjustment boss (104) to fix the defective bone flap (200) and the bone flap-side fixation end (105) together.

2. The device for fixing and reducing skull bone flaps according to claim 1, characterized in that: The cranial fixation end (101) is a semi-cylindrical structure with a radius of 5 mm and a cranial fixation hole in its center. The fixing titanium nail (106) fixes the cranial fixation end (101) to the skull through the fixing hole. The arc-shaped surface of the cranial fixation end faces the skull and a semi-cylindrical through groove is opened at the corresponding position of the skull. The cranial fixation end is embedded in the through groove and then fixed by the fixing titanium nail. The fixing titanium nail (106) extends out of the cranial fixation end and is fixed into the skull.

3. The device for fixing and reducing skull bone flaps according to claim 1, characterized in that: The bone flap side fixation end (105) has a scale-like structure and an adjustment boss (104) is provided in its center; the first titanium nail (102) fixes the bone flap side fixation end (105) to the defective bone flap by screwing into the adjustment boss (104).

4. The device for fixing and reducing skull bone flaps according to claim 1, characterized in that: The number of cranial fixators (100) is 3-6, and they are installed in a symmetrical manner at three or more points.

5. The device for fixing and reducing skull bone flaps according to claim 1, characterized in that: The cranial fixation end (101) is a semi-cylindrical structure with a radius of 5 mm; the bone flap fixation end (105) is a scale-like structure with a length of 10 mm and a width of 8 mm; the adjusting boss (104) has an inner diameter of 3 mm, an outer diameter of 4 mm, and a height of 6 mm; the lifting structure (103) is a spring with an inner diameter of 4.5 mm and a minimum compression length of 2 mm; the adjusting boss (104) has a 6 mm limit to prevent damage to brain tissue caused by excessive tightening force and excessive rotation stroke of the first titanium nail (102).

6. The device for fixing and reducing skull bone flaps according to claim 5, characterized in that: The first titanium nail (102) and the fixed titanium nail (106) have a cylindrical end radius of 1.5 mm and a length of 8 mm. By adjusting the rotation of the first titanium nail (102) to compress and elevate the structure (103) to different degrees, the defective bone flap (200) can be raised or lowered. The maximum elevation is 6 mm, and the descent does not exceed the lowest point of the skull fixator (100).

7. The device for fixing and reducing skull bone flaps according to claim 6, characterized in that: The lifting structure (103) can lift the defective bone flap (200) by rotating the first titanium nail (102) clockwise and using its elasticity; by rotating the first titanium nail (102) counterclockwise and compressing the lifting structure (103), the defective bone flap (200) is lowered, thereby reducing the distance between the defective bone flap (200) and the skull (300); the diameter of the head of the first titanium nail (102) should be greater than the diameter of the lifting structure (103); the maximum elasticity of the lifting structure (103) should be less than the maximum bearing capacity of the first titanium nail (102).

8. The device for fixing and reducing skull bone flaps according to claim 1, characterized in that: The cranial side fixation end (101), the first titanium nail (102), the lifting structure (103), the adjusting boss (104), the bone flap side fixation end (105), and the fixing titanium nail (106) are all made of medical titanium alloy.

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