A kind of individualized mandibular nerve positioning and protection guide plate of dental support type mandibular ramus sagittal split osteotomy

Abstract

This invention relates to a tooth-supported sagittal split osteotomy of the mandibular ramus, featuring an individualized mandibular nerve localization and protection guide. The guide includes a tooth-supporting fixation structure, a guide body structure, a mandibular nerve localization structure, an osteotomy guidance structure, and a nerve protection structure. The inner surface morphology of the tooth-supporting fixation structure matches the patient's dentition shape, forming a stable three-dimensional positioning relationship with the dentition by covering the crowns. One end of the guide body structure is connected to the tooth-supporting fixation structure, and the other end is connected to the nerve protection structure. The guide body structure extends upwards to the mandibular ramus region via the mandibular nerve localization structure and to the mandibular body region via the osteotomy guidance structure. The mandibular nerve localization structure is positioned at a corresponding location on the guide body structure and marked based on the location and course of the mandibular nerve canal reconstructed from preoperative CT imaging data. The mandibular nerve localization structure corresponds to the medial osteotomy line position of the sagittal split osteotomy of the mandibular ramus, and the osteotomy guidance structure corresponds to the longitudinal osteotomy line position of the mandibular body osteotomy.

Description

Technical Field

[0001] This invention relates to the field of oral and maxillofacial surgical instruments, and more specifically to a tooth-supported mandibular ramus sagittal split osteotomy individualized mandibular nerve localization and protection guide. Background Technology

[0002] Bilateral sagittal split osteotomy (BSSO) of the mandibular ramus is one of the most widely used surgical procedures in orthognathic surgery. It is primarily used to correct maxillofacial developmental abnormalities such as mandibular prognathism, mandibular retrusion, facial asymmetry, and some obstructive sleep apnea disorders. This procedure involves a sagittal osteotomy in the mandibular ramus region, allowing the distal bone segment to be moved anteriorly, posteriorly, or rotated, thereby reconstructing the occlusal relationship and improving facial profile.

[0003] In traditional surgical techniques, medial osteotomy of the mandibular ramus is usually performed via an intraoral approach. Due to the relatively narrow anatomical space in this area, the procedure relies primarily on an indirect field of vision. The medial osteotomy line generally begins in the area anterior and superior to the mandibular foramen and extends anteroinferiorly into the mandibular body region. This area is adjacent to important anatomical structures—the mandibular nerve canal and its entrance (mandibular foramen). Inaccurate localization can easily lead to damage to the mandibular nerve, resulting in complications such as sensory abnormalities in the lower lip and chin.

[0004] Currently, the most commonly used clinical methods for nerve localization rely primarily on preoperative imaging measurements. For example, CBCT or CT images are used to measure the distance between the entrance of the mandibular nerve canal (mandibular foramen) and the anterior border of the mandibular ramus. This distance serves as an important reference for determining the medial osteotomy height and depth during surgery. During the operation, the surgeon empirically locates the nerve in the medial region of the mandibular ramus based on preoperative measurements and performs the osteotomy in conjunction with anatomical landmarks.

[0005] However, in actual surgical procedures, there are significant anatomical limitations on the medial side of the mandibular ramus. The lingula, located anterior to the mandibular foramen, is a crucial bony landmark covering it. Under intraoral access conditions, due to limited surgical field exposure and obstruction by the lingula and surrounding soft tissues, surgeons often struggle to accurately identify the mandibular foramen and mandibular canal under direct vision. Therefore, current techniques still primarily rely on surgeon experience and indirect localization to perform osteotomy, making it difficult to achieve precise positioning and effective protection of the mandibular nerve.

[0006] Although existing technologies have provided some reference for the localization of the mandibular nerve through preoperative imaging measurements, the following problems still exist in actual clinical applications: (1) It is difficult to achieve precise localization of the mandibular nerve during the operation. Current techniques primarily rely on preoperative imaging measurements to obtain the positional parameters of the mandibular foramen. However, these measurements are merely static data from two-dimensional or three-dimensional images. During actual surgery, due to soft tissue traction, changes in surgical positioning, and limitations in surgical field exposure, surgeons find it difficult to accurately translate the imaging measurements into specific intraoperative anatomical locations, thus affecting the accuracy of nerve localization.

[0007] (2) The surgical procedure is highly dependent on the surgeon's experience. Traditional osteotomy methods rely mainly on the surgeon's experience to determine the location and depth of the osteotomy. The experience of different surgeons varies greatly, which can easily lead to insufficient stability and repeatability of the surgical procedure and increase the risk of damage to the mandibular nerve.

[0008] (3) Limited visual exposure in the medial osteotomy area The anatomical space in the medial region of the mandibular ramus is narrow and obscured by the lingula, pterygomandibular ligament, and surrounding soft tissue structures, making it difficult to directly visualize and identify the mandibular foramen and mandibular nerve canal during surgery, further increasing the difficulty of nerve localization and protection.

[0009] (4) Lack of auxiliary tools that can simultaneously achieve "nerve localization and osteotomy guidance" Currently, there is a lack of specialized positioning and protection devices for the medial osteotomy area of ​​the mandibular ramus in clinical practice. Most existing surgical instruments are general-purpose bone cutters or oscillating saws, which can only perform osteotomy operations and cannot provide precise nerve positioning and protection during surgery.

[0010] (5) Complications of nerve injury still have a certain incidence rate. Due to the above factors, mandibular nerve traction, compression, or direct damage may still occur during sagittal split osteotomy of the mandibular ramus, leading to postoperative complications such as abnormal sensation in the lower lip and chin, which affects the patient's postoperative quality of life.

[0011] In summary, existing techniques still have certain limitations in locating and protecting the mandibular nerve during sagittal split osteotomy of the mandibular ramus. Therefore, there is an urgent need for an auxiliary device or technical solution that can achieve individualized mandibular nerve localization and simultaneously guide a safe osteotomy path to improve the accuracy and safety of the surgical procedure. Summary of the Invention

[0012] To address at least one of the aforementioned technical problems, a first aspect of the present invention provides a tooth-supported sagittal osteotomy guide plate for mandibular nerve localization and protection, comprising a tooth-supporting fixation structure, a guide plate main structure, a mandibular nerve localization structure, an osteotomy guiding structure, and a nerve protection structure. The inner surface morphology of the tooth-supporting fixation structure matches the shape of the patient's dentition. The tooth-supporting fixation structure forms a repeatable three-dimensional positioning relationship with the patient's dentition by covering at least a portion of the tooth crown. One end of the guide plate main structure is connected to the tooth-supporting fixation structure, and the other end is connected to the nerve protection structure. The guide plate main structure extends upward to the mandibular ramus region via the mandibular nerve localization structure and extends to the mandibular body region via the osteotomy guiding structure. The guide plate main structure is individually designed based on the patient's three-dimensional jawbone data, and at least a portion of it... The guide plate conforms to the anterior border of the mandibular ramus and the bone surface of the mandibular body to transmit tooth support positioning information to the osteotomy area. The mandibular nerve positioning structure is set at the corresponding position of the main structure of the guide plate and marked according to the position of the mandibular nerve entering the mandibular nerve foramen and its course in the mandibular body reconstructed from preoperative CT image data. This is used to convert the spatial position information of the mandibular nerve in preoperative imaging into a positioning reference that can be identified during surgery. The mandibular nerve positioning structure corresponds to the medial osteotomy line of the sagittal split osteotomy of the mandibular ramus and forms a guide to limit the movement path of the osteotomy instrument and provides a certain degree of surgical field exposure. The nerve protection structure is set on the guide plate in the corresponding course area of ​​the mandibular nerve canal in the mandibular body, forming a physical isolation of the nerve area to limit the displacement of the instrument into the mandibular nerve area during osteotomy.

[0013] According to a first aspect of the present invention, the tooth support fixing structure is a dental sleeve type snap-fit ​​structure, and its inner surface is provided with a plurality of receiving grooves that match the shape of the patient's mandibular crown.

[0014] According to a first aspect of the invention, the nerve protection structure is a nerve protection baffle or a nerve protection flange protruding toward the mandibular nerve canal, the nerve protection structure being located between the mandibular nerve positioning structure and the osteotomy guiding structure.

[0015] According to a first aspect of the present invention, the mandibular nerve positioning structure includes a nerve canal entrance positioning mark and a nerve canal course projection mark in the mandibular body, wherein the nerve canal entrance positioning mark corresponds to the area above and in front of the mandibular foramen, and the course projection mark is arranged along the extension direction of the mandibular nerve canal.

[0016] According to a first aspect of the present invention, the osteotomy guiding structure includes an osteotomy guide groove and an osteotomy guide surface, the osteotomy guide groove extending along the longitudinal osteotomy line of the mandibular body, and the osteotomy guide surface being used to limit the lateral displacement of the osteotomy instrument.

[0017] According to a first aspect of the present invention, the main structure of the guide plate is individually designed so that its shape conforms to the anterior edge and medial region of the ascending ramus of the patient's mandible, and at least partially conforms to the lateral bone surface of the body of the mandible, thereby ensuring that the overall spatial position of the guide plate is consistent with the preoperative design.

[0018] According to a first aspect of the invention, the guide plate osteotomy guiding structure is individually designed to fit the lateral region of the mandibular body of the patient, and its guiding surface guides the longitudinal osteotomy line of the mandibular body osteotomy, and the extension direction of the osteotomy guide groove is consistent with the preoperatively designed osteotomy path.

[0019] According to a first aspect of the present invention, the tooth support and fixation structure, the guide plate main structure, the mandibular nerve positioning structure, the osteotomy guidance structure and the nerve protection structure are integrally molded structures and are individually manufactured through digital design and 3D printing technology.

[0020] According to a first aspect of the present invention, the tooth support fixation structure, the guide plate main structure, the mandibular nerve positioning structure, the osteotomy guidance structure, and the nerve protection structure are integrally formed and individually manufactured using digital design and 3D printing technology.

[0021] A second aspect of the present invention provides a method for designing an individualized mandibular nerve localization and protection guide for sagittal split osteotomy of the mandibular ramus based on the first aspect, characterized by comprising the following steps: Acquire patient's head CT image data; A three-dimensional model of the mandible, dentition, and mandibular nerve canal was reconstructed based on the CT image data. The tooth support and fixation structure is designed based on the reconstructed three-dimensional morphology of the dentition. The mandibular nerve positioning structure and nerve protection structure are designed based on the reconstructed three-dimensional position and course of the mandibular nerve canal. The osteotomy guiding structure is designed according to the preoperatively planned osteotomy path; The above structures are integrated digitally to form a three-dimensional digital model of the guide plate; The guide plate is manufactured using 3D printing technology based on the three-dimensional digital model. Attached Figure Description

[0022] The accompanying drawings, which illustrate various embodiments of the present invention, are described below. In the drawings, the same reference numerals denote the same parts. The drawings are not necessarily drawn to scale, and some parts may be enlarged to show the details of the present invention.

[0023] Figure 1 This is a schematic diagram of the individualized mandibular nerve localization and protection guide plate for sagittal split osteotomy of the mandibular ramus with tooth support according to the present invention, observed from different orientations. Figure 2 The front and top views are of the individualized mandibular nerve localization and protection guide plate for sagittal split osteotomy of the mandibular ramus according to the present invention, installed in the mandible. Figure 3 This is a side view of the individualized mandibular nerve localization and protection guide plate for the sagittal split osteotomy of the mandibular ramus according to the present invention, installed in the mandible. Figure 4 This is an exploded view of the individualized mandibular nerve localization and protection guide plate for sagittal split osteotomy of the mandibular ramus according to the present invention, installed in the mandible. It shows the position of the mandibular nerve in the mandible and how the individualized mandibular nerve localization and protection guide plate for sagittal split osteotomy of the mandibular ramus according to the present invention locates, protects, and guides the osteotomy of the nerve. Detailed Implementation

[0024] The embodiments of this application will be further described in detail below with reference to the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to illustrate the principles of this application by way of example, but should not be used to limit the scope of this application. This application can be implemented in many different forms and is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

[0025] These embodiments are provided to make the application thorough and complete, and to fully express the scope of the application to those skilled in the art. It should be noted that, unless otherwise specifically stated, the relative arrangement of components and steps, material composition, numerical expressions and values ​​illustrated in these embodiments should be interpreted as merely exemplary and not as limiting.

[0026] All terms used in this application have the same meaning as understood by one of ordinary skill in the art to which this application pertains, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant art, and not as idealized or highly formalized, unless expressly defined herein.

[0027] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the specification.

[0028] Figure 1 This is a schematic diagram of the individualized mandibular nerve localization and protection guide for sagittal split osteotomy of the mandibular ramus according to the present invention, viewed from different orientations. (See diagram for reference.) Figure 1As shown, the individualized mandibular nerve localization and protection guide for sagittal split osteotomy of the mandibular ramus of the present invention with tooth support includes a tooth support and fixation structure 1, a guide body structure 2, a mandibular nerve localization structure 3, an osteotomy guiding structure 4, and a nerve protection structure 5, wherein: The dental support and fixation structure 1 is designed as a plate-like structure, its shape conforming to the patient's oral cavity. Its inner surface morphology is designed to match the shape of the patient's dentition, i.e., it has multiple groove structures that match the shape of the patient's dentition. In some preferred embodiments, the dental support and fixation structure 1 is a clip-on structure, with its multiple groove structures forming receiving portions adapted to the crowns of the premolars and molars on the same side of the patient's mandible. Through the covering, fitting, or snapping of the corresponding crowns by these receiving portions, the dental support and fixation structure 1 can achieve repeatable placement on the patient's dentition. That is, during multiple placement and removal processes, the guide plate can be reinstalled on the dentition with a basically consistent spatial position, thereby forming a stable three-dimensional positioning relationship. This structure can effectively improve the repeatability and stability of guide plate positioning and provide a unified spatial reference for subsequent mandibular nerve positioning, osteotomy guidance, and nerve protection.

[0029] like Figure 1 As shown in the lower right figure, a stable three-dimensional positioning relationship is formed with the dentition by covering the tooth crown. In use, the supporting fixation structure 1 is bitten down on by the patient's teeth, thus providing a stable positioning reference for the individualized mandibular nerve positioning and protection guide for sagittal split osteotomy of the mandibular ramus according to the present invention. This ensures the accurate spatial position of the guide after installation during surgery and prevents the guide from moving or rotating during the surgical procedure. Due to the high anatomical stability of the dentition, this tooth supporting fixation structure 1 can significantly improve the positioning accuracy of the guide.

[0030] The main structure 2 of the guide plate extends obliquely downward from one side of the tooth support and fixation structure 1 to the mandibular ramus region. One end of its extension connects to the mandibular nerve positioning structure 3, and the other end connects to the osteotomy guiding structure 4. Through individualized design, the main structure 2 conforms to the anterior and medial regions of the patient's mandibular ramus, ensuring that the overall spatial position of the main structure 2 is consistent with the preoperative design. Furthermore, in some embodiments, in addition to conforming to the anterior and medial regions of the mandibular ramus, the main structure 2 also conforms at least partially to the lateral surface of the mandibular body. The main structure 2 is individually designed based on the patient's three-dimensional reconstruction model of the jawbone, enabling it to overcome the spatial difference between the tooth support region and the osteotomy operation area, and stably transmit the positioning information formed by the tooth support and fixation structure 1 on the dentition to the mandibular ramus region and the mandibular body region. With this structure, the guide plate can achieve composite positioning on multiple anatomical contact surfaces during surgery, thereby further reducing positioning errors. The main structure 2 of the guide plate connects and supports various functional structures, and transmits the tooth support positioning information realized by the tooth support fixation structure 1 to the osteotomy area, thereby ensuring that the guide plate has stable spatial positioning in the surgical area.

[0031] In some embodiments of the present invention, the tooth support and fixation structure is preferably a clip-on structure with multiple receiving grooves on its inner surface that match the shape of the patient's tooth crowns. These receiving grooves correspond to the crown shapes of the premolars and molars on one side of the patient's mandible, respectively. By covering or clamping at least a portion of the crowns, the guide plate can form a stable and repeatable three-dimensional positioning relationship with the patient's dentition during wear. Because the dentition itself has high anatomical stability and repeatability, the tooth support and fixation structure can provide a reliable initial positioning reference for the entire guide plate, thereby reducing the risk of displacement, rotation, or tilting of the guide plate during surgery.

[0032] The mandibular nerve localization structure 3 is connected at one end to the main guide plate structure 2, and the other end is a free end, such as... Figure 1As shown, the free end is a slender, hook-shaped or beak-shaped protrusion that extends from the main structure 2 of the guide plate and is slightly arc-shaped, gradually tapering to a point at the end. The mandibular nerve positioning structure 3 is marked based on the location and course of the mandibular nerve canal reconstructed from preoperative CT image data. The markings of the mandibular nerve positioning structure 3 include: a nerve canal entrance positioning mark and a nerve canal course projection mark in the mandibular body. Its function is to provide osteotomy guidance under nerve protection conditions during surgery, transforming the spatial location of the mandibular nerve in imaging into an intraoperatively identifiable reference structure, helping the surgeon to accurately determine the nerve location area. In some preferred embodiments, the mandibular nerve positioning structure 3 includes an arc-shaped indicator arm extending from the main structure 2 of the guide plate to the medial side of the mandibular ramus. One end of the arc-shaped indicator arm is connected to the main structure 2 of the guide plate, and the other end is a free end extending towards the mandibular foramen region. The spatial position of this arc-shaped indicator arm is determined based on the three-dimensional model of the mandibular nerve canal reconstructed from the patient's preoperative CT or CBCT image data, which corresponds to the nerve canal entrance location and the mandibular nerve canal course projection within the mandible. Therefore, the spatial location information of the mandibular nerve obtained from preoperative imaging can be transformed into an identifiable and referable physical positioning structure during surgery. This allows the surgeon to intuitively determine the danger zone and safe osteotomy range of the mandibular nerve, even with an intraoral approach and limited field of vision. The arc-shaped indicator arm can be curved, hooked, or beak-shaped, and its shape should preferably adapt to the anatomical space of the medial side of the mandibular ramus and provide clear positioning guidance. This invention does not impose strict limitations on this.

[0033] One end of the osteotomy guiding structure 4 is connected to the main guide plate structure 2, and the other end is a free end, such as... Figure 1 As shown. The osteotomy guide structure 4 corresponds to the longitudinal osteotomy line position of the mandibular body osteotomy. The osteotomy guide structure may include an osteotomy guide groove and an osteotomy guide surface, the functions of which are: to guide the operating direction of the osteotome or oscillating saw; to control the osteotomy position; to standardize the osteotomy path and reduce operating errors. In some embodiments, the osteotomy guide structure 4 forms a guide portion for defining the movement path of the osteotomy instrument. The guide portion may include an osteotomy guide groove extending along the longitudinal osteotomy line of the mandibular body, and an osteotomy guide surface that cooperates with the osteotomy guide groove. The osteotomy guide groove can be used to define the entry position and extension direction of the osteotomy instrument, and the osteotomy guide surface can be used to limit the lateral displacement of the osteotomy instrument during operation, so that the osteotome, oscillating saw or other osteotomy instrument moves stably along the preoperatively designed osteotomy path, improving the consistency of the osteotomy position and direction. Preferably, the extension direction of the osteotomy guide groove is consistent with the preoperatively designed mandibular body osteotomy path, so that the actual osteotomy line formed during the operation is as close as possible to the preoperatively planned osteotomy line.

[0034] A nerve protection structure 5 is positioned on the guide plate in the region corresponding to the mandibular nerve canal, as shown in the figure. Its location is on the downward extension of the main guide plate structure 2, between the mandibular nerve positioning structure 3 and the osteotomy guiding structure 4. This nerve protection structure 5 provides physical isolation to the mandibular nerve region. The nerve protection structure 5 can take the form of a nerve protection baffle or a nerve protection flange, but the invention is not limited to these. The main function of the nerve protection structure 5 is to provide mechanical protection to the mandibular nerve during osteotomy, preventing the osteotome or saw blade from entering the nerve region and reducing the risk of nerve injury during surgery. In some preferred embodiments, the nerve protection structure 5 is located between the mandibular nerve positioning structure 3 and the osteotomy guiding structure 4, and is positioned on the guide plate in the region corresponding to the mandibular nerve canal, forming a safety barrier between the osteotomy instrument's operating path and the area where the nerve is located. The nerve protection structure 5 can be a plate-shaped nerve protection baffle or a nerve protection flange protruding towards the mandibular nerve canal. Regardless of the form used, it can serve as a physical limiting structure during osteotomy. When the instrument deviates from the predetermined osteotomy path and moves toward the nerve region, the nerve protection structure 5 can block, guide, or limit the instrument to restrict its movement toward the mandibular nerve region.

[0035] In some embodiments of the present invention, the nerve protection structure is disposed on the guide plate in the region corresponding to the mandibular nerve canal and located between the mandibular nerve positioning structure and the osteotomy guiding structure. During osteotomy, this nerve protection structure can act as a physical barrier or safety boundary for instrument movement. When the osteotome, saw blade, or other osteotomy instruments deviate from the predetermined path and approach the nerve region, the nerve protection structure can block or limit the instrument, thereby restricting its displacement towards the mandibular nerve region and reducing the risk of direct nerve damage during surgery.

[0036] The aforementioned tooth support and fixation structure 1, guide plate main structure 2, mandibular nerve positioning structure 3, osteotomy guiding structure 4, and nerve protection structure 5 are integrated into a single guide plate device, which is then individually manufactured using digital design and 3D printing technology.

[0037] In some embodiments of the present invention, the main structure of the guide plate is individually designed based on the patient's three-dimensional jawbone data, and at least part of its shape conforms to the anterior border of the mandibular ramus, the medial bone surface of the mandibular ramus, and the lateral bone surface of the mandibular body. Through this conformation, the spatial positioning information established by the tooth support fixation structure on the dentition can be stably transmitted to the osteotomy area and the nerve protection area via the main structure of the guide plate, thereby ensuring that the functional structure of the guide plate in the surgical area is consistent with the preoperative design position and improving the positioning accuracy of the guide plate in complex anatomical areas.

[0038] Figure 2These are front and top views of the individualized mandibular nerve localization and protection guide plate for sagittal split osteotomy of the mandibular ramus according to the present invention, installed in the mandible. Figure 3 This is a side view of the individualized mandibular nerve localization and protection guide plate for sagittal split osteotomy of the mandibular ramus according to the present invention, with the plate installed in the mandible. Figure 4 This is an exploded view of the individualized mandibular nerve localization and protection guide plate for sagittal split osteotomy of the mandibular ramus according to the present invention, installed in the mandible. It illustrates the position of the mandibular nerve within the mandible and how the individualized mandibular nerve localization and protection guide plate for sagittal split osteotomy of the mandibular ramus according to the present invention locates, protects, and guides the nerve during osteotomy. Figures 2 to 4 As shown, after the tooth support and fixation structure 1 is installed on the same side of the patient's mandibular dentition, the main guide structure 2 extends along the tooth support area to the mandibular surgical area, and is respectively attached to the anterior border of the mandibular ramus, the medial bone surface of the mandibular ramus, and the lateral bone surface of the mandibular body. The mandibular nerve positioning structure 3 is located on the upper part of the main guide structure 2 and extends to the medial side of the mandibular ramus. The nerve protection structure 5 is set between the mandibular nerve positioning structure 3 and the osteotomy guidance structure 4. The osteotomy guidance structure 4 is located on the lateral side of the mandibular body and corresponds to the preoperatively designed longitudinal osteotomy line. The above structures cooperate with each other in space, so that the guide can simultaneously provide stable positioning, nerve positioning, instrument guidance, and nerve protection functions during the operation. With the help of the positioning relationship established between the tooth support and fixation structure 1 and the dentition, the main guide structure 2 can transmit the stable positioning information of the dentition area to the mandibular ramus and mandibular body surgical area far away from the dentition, thereby ensuring the spatial accuracy of each functional structure during the operation.

[0039] In some embodiments of the present invention, the mandibular nerve localization structure is not merely used to mark the approximate anatomical region, but is individually set based on the three-dimensional spatial location of the mandibular nerve canal reconstructed from the patient's preoperative CT or CBCT imaging data. This structure allows the location of the mandibular nerve canal entrance, its course, and its spatial relationship with surrounding bony structures, obtained from preoperative imaging, to be transformed into a directly identifiable localization reference during surgery. This enables the surgeon to accurately determine the nerve's location and safe operating range even under limited exposure conditions.

[0040] like Figures 2-4 As shown, the tooth support and fixation structure 1 is fixed to the patient's dentition to provide overall stability and protection for the guide plate. The main guide plate structure 2 extends downwards from the anterior side of the tooth support and fixation structure 1 and fits against the bone surface of the lateral aspect of the mandibular body and the anterior border of the mandibular ramus. One end of the mandibular nerve positioning structure 3 is connected to the main guide plate structure 2, and the other end is an arc-shaped extension segment. In the figure, this arc-shaped extension segment fits against the medial bone surface of the mandibular ramus. The mandibular nerve positioning structure 3 is marked according to the location and course of the mandibular nerve canal reconstructed from preoperative CT image data, as shown below. Figure 4As shown. The osteotomy guiding structure 4 is located on the lateral side of the mandibular body. It extends from the main guide plate structure 2 and forms an osteotomy guiding groove and osteotomy guiding surface on it, thus providing a clear operating path for the osteotome or oscillating saw. The nerve protection structure 5 is set on the positioning and protection guide plate in the area corresponding to the mandibular nerve canal, forming a physical isolation of the mandibular nerve area. The nerve protection structure 5 can take the form of a nerve protection baffle or a nerve protection flange, such as... Figure 4 As shown.

[0041] In some embodiments of the present invention, the osteotomy guiding structure forms a guide portion for defining the movement path of the osteotomy instrument. The guide portion may be constructed by means of a guide groove, a guide surface, or a combination of both, and is used to limit the entry position, extension direction, and lateral deviation of the osteotome, oscillating saw, or other osteotomy instruments, so that the actual osteotomy path is as consistent as possible with the preoperative design path, reducing osteotomy deviations caused by human judgment errors.

[0042] The individualized mandibular nerve localization and protection guide for sagittal split osteotomy of the mandibular ramus according to the present invention is designed using digital technology. Its basic process includes: 1) acquiring CT images of the patient's skull; 2) three-dimensional reconstruction of the mandible and mandibular canal structure; 3) designing a tooth support structure based on the dentition morphology; 4) designing a localization and protection structure in conjunction with the nerve location; 5) designing an osteotomy guide structure; and 6) manufacturing the guide using 3D printing technology. Individualized design of the guide can be achieved through the above process.

[0043] In some preferred embodiments, the tooth support fixation structure 1 is a clip-on structure with multiple receiving grooves on its inner surface that match the crown shape of the premolars and molars on the same side of the patient's mandible. By covering or snapping onto at least part of the crowns, the guide plate can be repeatedly positioned on the dentition and a stable three-dimensional positioning relationship can be formed. The main body structure 2 of the guide plate is individually designed based on the three-dimensional model of the patient's jawbone. At least part of its shape conforms to the anterior edge of the mandibular ramus, the medial bone surface of the mandibular ramus, and the lateral bone surface of the mandibular body, thereby stably transmitting the spatial positioning information established by the tooth support fixation structure 1 to the osteotomy area. The mandibular nerve positioning structure 3 may include an arc-shaped indicator arm extending from the main body structure 2 down to the medial side of the mandibular ramus. Its free end extends toward the mandibular foramen region and, combined with the nerve canal entrance positioning mark and the nerve course projection mark, transforms the spatial position information of the mandibular nerve obtained from preoperative imaging into a positioning reference that can be identified during surgery. The osteotomy guiding structure 4 can form a guide portion for defining the movement path of the osteotomy instrument. The guide portion includes an osteotomy guiding groove and / or an osteotomy guiding surface, wherein the osteotomy guiding groove extends along the preoperatively designed longitudinal osteotomy path of the mandibular body, and the osteotomy guiding surface is used to limit lateral deviation of the instrument. The nerve protection structure 5 is located between the mandibular nerve positioning structure 3 and the osteotomy guiding structure 4, and is set on the guide plate in the area corresponding to the mandibular nerve canal. It can be in the form of a plate-shaped nerve protection baffle or a nerve protection flange protruding towards the mandibular nerve canal, so as to block, guide, or limit the instrument approaching the nerve area during osteotomy, thereby reducing the risk of mandibular nerve injury.

[0044] Compared with the prior art, the individualized mandibular nerve localization and protection guide for sagittal split osteotomy of the mandibular ramus provided by the present invention has the following technical effects: (1) Achieve individualized and precise localization of the mandibular nerve to improve the accuracy of intraoperative localization. This invention utilizes preoperative CT imaging data for three-dimensional reconstruction and provides individualized analysis and design of the spatial location of the mandibular nerve canal. This ensures that the nerve localization structure accurately reflects the actual location of the mandibular nerve within the mandible. Through nerve localization markers or structures on the surgical guide, imaging data can be transformed into intraoperatively identifiable localization references, significantly improving the accuracy of mandibular nerve localization and reducing errors caused by experience-based judgment.

[0045] (2) To provide stable guidance for osteotomy operations and to standardize the position and direction of osteotomy. This invention incorporates an osteotomy guidance structure on a guide plate, providing a clear operating path for the osteotome or oscillating saw via guide grooves or surfaces, ensuring that the position and direction of the osteotomy line remain consistent with the preoperative design. This structure effectively controls the osteotomy height and direction, improving the controllability and repeatability of the surgical procedure.

[0046] (3) Provides physical protection for the mandibular nerve, reducing the risk of nerve damage. The present invention incorporates a nerve protection structure on the guide plate, creating a safe interval or physical barrier between the osteotomy area and the area where the nerve is located. This provides mechanical protection for the mandibular nerve during the osteotomy procedure, preventing the bone cutter or saw blade from entering the nerve area and thus reducing the probability of damage to the inferior alveolar nerve.

[0047] (4) Improve surgical stability and reduce reliance on the surgeon's experience. In traditional sagittal split osteotomy of the mandibular ramus, the determination of the osteotomy location largely depends on the surgeon's experience. This invention achieves stable positioning of the guide plate on the dentition through a tooth support structure, and accurately transfers the preoperatively designed osteotomy path and nerve location information to the intraoperative procedure through the guide plate, thereby improving the consistency and repeatability of the surgical procedure.

[0048] (5) Improve surgical safety and reduce the incidence of complications Because this invention can simultaneously achieve three functions—nerve localization, osteotomy guidance, and nerve protection—it can effectively reduce the risks of intraoperative nerve damage and osteotomy deviation, help reduce postoperative complications such as sensory abnormalities in the lower lip and chin, and improve the quality of postoperative recovery for patients.

[0049] (6) It has good clinical promotion value and economic benefits. This invention enables personalized manufacturing through digital design and 3D printing technology, resulting in a relatively simple production process. It allows for rapid design and fabrication based on the anatomical structures of different patients. This device can be widely used in orthognathic surgery, demonstrating significant clinical application value and economic benefits.

[0050] (7) Shorten the operation time and improve the efficiency of the operation. This invention uses preoperative digital design to pre-determine the location of the mandibular nerve and the osteotomy path, and uses a guide plate to achieve precise guidance during the operation. This reduces the number of steps the surgeon needs to repeatedly measure, judge and adjust the osteotomy position during the operation, thereby shortening the operation time and improving the overall surgical efficiency.

[0051] (8) Improve the efficiency of surgical resource utilization and reduce medical costs. Because this invention can improve the accuracy and stability of surgical procedures, reduce additional treatment and postoperative complication management caused by osteotomy deviation or nerve damage, it helps to reduce surgical risks and related medical costs. At the same time, the shortened operation time can improve operating room turnover efficiency, allowing for more efficient use of medical resources.

[0052] (9) Improve surgical safety and enhance patients' postoperative quality of life. By accurately locating and effectively protecting the mandibular nerve, the incidence of complications such as sensory abnormalities in the lower lip and chin caused by inferior alveolar nerve injury can be reduced, thereby improving postoperative functional recovery, enhancing patients' quality of life and medical satisfaction.

[0053] (10) Promote the application of digitalization and precision medicine in orthognathic surgery This invention combines three-dimensional imaging reconstruction, digital design, and 3D printing technology to realize the design and application of personalized surgical aids. This contributes to promoting the application and development of digital medical technology in oral and maxillofacial surgery and has a positive impact on improving the precision of orthognathic surgery. The personalized mandibular nerve localization and protection guide for sagittal split osteotomy of the mandibular ramus according to this invention is designed using digital technology, and its basic process may include: 1) Obtain the patient's head CT or CBCT imaging data, and, if necessary, obtain digital model data of the dental arch; 2) Reconstruct a three-dimensional model of the patient's mandible, dentition, and mandibular nerve canal based on the image data; 3) Design a dental support and fixation structure based on the three-dimensional model of the dentition to form a receiving groove that matches the patient's crown and a positioning relationship that allows for repeated placement; 4) Design the mandibular nerve localization structure based on the three-dimensional model of the mandibular nerve canal, and determine the location of its corresponding mandibular foramen region and the projection of the nerve course; 5) Design nerve protection structures based on the location of the mandibular nerve canal and the predetermined safety boundaries; 6) Design an osteotomy guide structure based on the preoperative osteotomy plan, ensuring that its guiding path is consistent with the preoperative planned osteotomy path; 7) The tooth support and fixation structure, the main structure of the guide plate, the mandibular nerve positioning structure, the osteotomy guidance structure and the nerve protection structure are modeled as a whole, and individualized manufacturing is carried out using 3D printing technology.

[0054] Through the above process, the guide plate can simultaneously meet the comprehensive needs of tooth support positioning, nerve positioning, nerve protection, and osteotomy path guidance.

[0055] Based on the repeatable positioning characteristics of the tooth support structure, a stable spatial reference is achieved. This invention establishes a repeatable three-dimensional positioning relationship between the tooth support fixation structure and the patient's dentition through a dental brace-type tooth support fixation structure, and uses the main structure of the guide plate to stably transfer this positioning relationship to the mandibular ramus and mandibular body osteotomy area, which helps to improve the accuracy of guide plate installation and stability during operation.

[0056] The embodiments of this application have now been described in detail. To avoid obscuring the concept of this application, some details known in the art have not been described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein based on the above description.

[0057] While specific embodiments of this application have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of this application. Those skilled in the art should understand that modifications can be made to the above embodiments or equivalent substitutions can be made to some technical features without departing from the scope and spirit of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any manner.

Claims

1. A personalized mandibular nerve localization and protection guide for sagittal split osteotomy of the mandibular ramus supported by teeth, comprising a tooth-supporting fixation structure, a guide body structure, a mandibular nerve localization structure, an osteotomy guiding structure, and a nerve protection structure. The inner surface morphology of the tooth support and fixation structure matches the shape of the patient's dentition. The tooth support and fixation structure forms a repeatable three-dimensional positioning relationship with the patient's dentition by covering at least a portion of the tooth crown. One end of the guide plate main structure is connected to the tooth support and fixation structure, and the other end is connected to the nerve protection structure. It extends upwards to the mandibular ramus region via the mandibular nerve positioning structure and to the mandibular body region via the osteotomy guiding structure. The guide plate main structure is individually designed based on the patient's three-dimensional jawbone data, and at least a portion of its shape conforms to the anterior border of the mandibular ramus and the bone surface of the mandibular body to transmit tooth support positioning information to the osteotomy area. The mandibular nerve positioning structure is located at the... The corresponding positions of the main structure of the guide plate are marked according to the location of the mandibular nerve entering the mandibular foramen and its course in the mandibular body reconstructed from preoperative CT image data. This is used to convert the spatial location information of the mandibular nerve in preoperative imaging into a identifiable positioning reference during surgery. The mandibular nerve positioning structure corresponds to the medial osteotomy line of the sagittal split osteotomy of the mandibular ramus and forms a guide part to limit the movement path of the osteotomy instrument and provides a certain degree of surgical field exposure. The nerve protection structure is set on the guide plate in the corresponding course area of ​​the mandibular canal in the mandibular body, forming a physical isolation of the nerve area to limit the displacement of the instrument into the mandibular nerve area during osteotomy.

2. The individualized mandibular nerve localization and protection guide plate for sagittal split osteotomy of the mandibular ramus as described in claim 1, wherein the tooth support fixation structure is a tooth sleeve type snap-fit ​​structure, and its inner surface is provided with multiple receiving grooves that match the shape of the patient's mandibular crown.

3. The individualized mandibular nerve location and protection guide for sagittal split osteotomy of the mandibular ramus supported by the teeth according to claim 1, wherein, The nerve protection structure is a nerve protection baffle or a nerve protection flange protruding toward the mandibular nerve canal, and the nerve protection structure is located between the mandibular nerve positioning structure and the osteotomy guiding structure.

4. The individualized mandibular nerve location and protection guide for sagittal split osteotomy of the mandibular ramus supported by the teeth according to claim 1, wherein, The mandibular nerve localization structure includes a nerve canal entrance location marker and a nerve canal course projection marker in the mandibular body, wherein the nerve canal entrance location marker corresponds to the area above and in front of the mandibular foramen, and the course projection marker is set along the extension direction of the mandibular nerve canal.

5. The individualized mandibular nerve localization and protection guide for sagittal split osteotomy of the mandibular ramus with tooth support as described in claim 1, wherein, The osteotomy guiding structure includes an osteotomy guide groove and an osteotomy guide surface. The osteotomy guide groove extends along the longitudinal osteotomy line of the mandibular body, and the osteotomy guide surface is used to limit the lateral displacement of the osteotomy instrument.

6. The individualized mandibular nerve localization and protection guide for sagittal split osteotomy of the mandibular ramus with tooth support as described in claim 1, wherein, The main structure of the guide plate is designed individually to fit the anterior edge and medial region of the mandibular ramus, and at least partially fit the lateral surface of the mandibular body, thereby ensuring that the overall spatial position of the guide plate is consistent with the preoperative design.

7. The individualized mandibular nerve localization and protection guide for sagittal split osteotomy of the mandibular ramus with tooth support as described in claim 1, wherein, The guide plate osteotomy guiding structure is individually designed to fit the lateral region of the patient's mandibular body. Its guiding surface guides the longitudinal osteotomy line of the mandibular body osteotomy, and the extension direction of the osteotomy guide groove is consistent with the preoperatively designed osteotomy path.

8. The individualized mandibular nerve localization and protection guide for sagittal split osteotomy of the mandibular ramus with tooth support as described in claim 1, wherein, The tooth support and fixation structure, the guide plate main structure, the mandibular nerve positioning structure, the osteotomy guidance structure, and the nerve protection structure are all integrally molded structures, and are individually manufactured through digital design and 3D printing technology.

9. The individualized mandibular nerve positioning and protection guide plate for sagittal split osteotomy of the mandibular ramus with tooth support as described in claim 1, wherein the tooth support fixation structure, the main structure of the guide plate, the mandibular nerve positioning structure, the osteotomy guidance structure and the nerve protection structure are integrally formed and individually manufactured through digital design and 3D printing technology.

10. A method for designing an individualized mandibular nerve localization and protection guide for sagittal split osteotomy of the mandibular ramus with tooth support as described in any one of claims 1 to 9, characterized in that, Includes the following steps: Acquire patient's head CT image data; A three-dimensional model of the mandible, dentition, and mandibular nerve canal was reconstructed based on the CT image data. The tooth support and fixation structure is designed based on the reconstructed three-dimensional morphology of the dentition. The mandibular nerve positioning structure and nerve protection structure are designed based on the reconstructed three-dimensional position and course of the mandibular nerve canal. The osteotomy guiding structure is designed according to the preoperatively planned osteotomy path; The above structures are integrated digitally to form a three-dimensional digital model of the guide plate; The guide plate is manufactured using 3D printing technology based on the three-dimensional digital model.

Images