RU223198U1 - Device for surgical treatment of deformity in the area of the base of the condylar process of the mandible - Google Patents

Abstract

The utility model relates to medicine, namely to maxillofacial surgery and surgical dentistry, and can be used for osteosynthesis of bone fragments in the surgical treatment of post-traumatic deformities in the area of the base of the condylar process of the mandible. The device is made according to the computed tomography data of a specific patient and repeats the correct anatomical shape of the lower jaw in the area of deformation. The device consists of two “ladders” with one common support corresponding to the ascending buttress of the mandible. The support of one of the “clamp ladders” for the posterior edge of the ramus of the mandible is located posterior to the condylar process of the mandible. The support of the other “ladder” is parallel to the coronoid notch of the mandible. The joints of the supports and rungs of the “stairs” are smoothed. At the intersection points of the supports and rungs of the “stairs” there are holes for fastening with screws. The device makes it possible to increase the positioning accuracy and stability of bone fragments during surgical treatment of deformity of the condylar process of the mandible.

Description

The utility model relates to medicine, namely to maxillofacial surgery and surgical dentistry, and can be used for osteosynthesis of bone fragments in the surgical treatment of deformities in the area of the base of the condylar process of the mandible.

The main method of surgical treatment of fractures and deformities of the lower jaw in the area of the base of the condylar process is osteotomy followed by reposition of bone fragments and osteosynthesis using standard titanium mini-plates. The location of the mini-plates and fixing screws is determined by the surgeon during surgery according to the preoperative X-ray examination and the ideal osteosynthesis lines in the area of the condylar process, drawn in accordance with the direction of the ascending mandibular buttress.

An individual surgical template is known (utility model patent RU 213082) for performing osteosynthesis for a fracture of the condylar process of the mandible, consisting of a body made of biocompatible plastic, made in the form of a plate 1.5 mm thick, with recesses in the area where titanium extra-bone mini-plates are located and holes for drilling and installation of screws and three clasps: in the area of the mandibular notch above the fracture line there is an upper clasp, on the posterior edge of the lower jaw branch below the fracture line there is a rear clasp, the upper and rear clasps have a bend of 5 mm, and the front clasp is made without a bend . Its disadvantage is that the direct fixation device is standard titanium mini-plates, which do not have additional clasps for more stable fixation and correct positioning of fragments of the lower jaw, which is necessary in the treatment of deformity.

An implant for osteosynthesis of fragments in case of a fracture of the condylar process of the mandible is known (patent RU 2676399). The known implant contains a base and a shoulder, each of which is made in the form of elongated links from disks with holes for placing fixation screws and flat plates connecting the disks to each other, while the shoulder is connected to the outermost disk of the base and is located on one side of the base perpendicular to the base, has continuation in the form of two additional links interconnected, one of which is located at a right angle to the shoulder at its end, and the other link is located at an acute angle to the base. The disadvantage of the device is the lack of landmarks in the device that allow accurately restoring the correct anatomy of the lower jaw, significant time costs for repositioning fragments, which lengthens the duration of the surgical intervention.

The problem to be solved by the utility model is the development of an individual device that ensures the accuracy of positioning and stability of bone fragments during the surgical treatment of deformities of the lower jaw in the area of the base of the condylar process.

The technical result of the proposed utility model is to increase the positioning accuracy and stability of bone fragments during surgical treatment of deformity of the condylar process of the mandible.

The technical result is achieved by an individual device made of titanium alloy, which is a curved body, made according to computed tomography data of a particular patient, repeating the correct anatomical shape of the lower jaw in the area of deformation, consisting of two “stairs” with one common support corresponding to the ascending buttress of the lower jaw , while the support of one of the “clasp ladders” is located along the posterior edge of the ramus of the lower jaw, and the support of the other “ladder” is parallel to the coronal notch of the lower jaw, the joints of the supports and crossbars of the “ladders” are smoothed, at the points of intersection of the supports and crossbars of the “ladders” There are holes for fastening with screws.

The utility model is illustrated by figures, where

in fig. Figure 1 shows a model of the patient’s lower jaw with the correct anatomy of the condylar process of the mandible and the device restored (sagittal projection);

in fig. 2 - model of the patient’s lower jaw with the correct anatomy of the condylar process of the mandible and the device restored (transversal projection).

The proposed individual device is planned on the basis of multislice computed tomography of the bones of the facial skeleton. A 3D modeling program creates a 3D model of the patient's lower jaw. A virtual osteotomy is performed (Fig. 1, item 1) and comparison of bone fragments in the deformation zone, thereby ensuring the restoration of the correct anatomy of the lower jaw. The proposed device is modeled in such a way that the common support of the two “stairs” (Fig. 1, item 2) forming the device is located anterior to the posterior edge of the lower jaw branch and in accordance with the ascending buttress of the lower jaw according to the restored anatomy of the lower jaw. Another support of the “clasp ladder” is modeled along the posterior edge of the lower jaw branch (Fig. 1, item 3, Fig. 2, item 3). The crossbars of the “clasp ladder” (Fig. 1, item 4) are modeled taking into account the course of the osteotomy line and the anatomy of the mandibular nerve canal so that the osteotomy line remains between the crossbars, the angle between the supports and the crossbars is 90°. The support of the other “staircase” is modeled parallel to the coronal notch of the mandible (Fig. 1, item 5), and its crossbars are modeled at the same levels of common support as the crossbars of the “clasp ladder” for the posterior edge of the mandibular ramus at an angle of 90° to the common support (Fig. 1, item 6). Smooth out the joints of the supports and rungs of the “stairs” to increase the area of their intersection. The supports and rungs of the “stairs” repeat the relief of the restored anatomy of the lower jaw. At the intersection points of the supports and rungs of the “stairs,” holes for fastening with screws are modeled.

The device is used as follows:

perform a traditional retromaxillary surgical approach to the condylar process of the mandible. Osteotomy of the lower jaw is performed in accordance with preoperative planning. Bone fragments of the jaw are reduced to the correct anatomical position under bite control. The proposed device is applied, which allows precise reduction and positioning of fragments in accordance with preoperative planning, and also provides reliable rigid fixation of osteotomized bone fragments of the condylar process of the mandible. Secure the device with screws.

The “clasp ladder,” made in accordance with the correct anatomical shape of the condylar process and the ramus of the mandible, allows you to control the correct reposition and position, increase the stability of the fixation of bone fragments, which ultimately reduces the operation time.

Clinical example of using the device.

Patient G., 51 years old. History: suffered a domestic injury. The patient turned to the maxillofacial surgeon of the city clinical hospital, was examined by the doctor on duty, an X-ray examination was performed and a closed fracture of the lower jaw was diagnosed at the base of the right condylar process with displacement of the fragments. The patient underwent intermaxillary fixation in the department of maxillofacial surgery of the city clinical hospital, was prescribed antibiotic prophylaxis, symptomatic treatment, an individual diet, physiotherapeutic procedures and was referred to a dental surgeon for outpatient treatment. After 1 week, the patient began to notice pain in the area of the right temporomandibular joint, and a persistent feeling of improper closure of the teeth appeared. 4 weeks after removal of the intermaxillary fixation, pain in the area of the right temporomandibular joint and the feeling of improper closure of the teeth persisted, and difficulty chewing food appeared. The patient was consulted by a maxillofacial surgeon, and MSCT of the maxillofacial area was performed. Deformation of the lower jaw in the area of the base of the right condylar process was diagnosed, and surgical treatment was recommended. The proposed individual device was manufactured. Based on MSCT data, a three-dimensional model of the patient’s lower jaw was created in a graphic editor, a virtual osteotomy was performed and bone fragments were compared in the area of post-traumatic deformity, and the correct anatomy of the lower jaw was restored. The common support of the two “ladders” forming the device was placed anterior to the posterior edge of the condylar process and the ramus of the mandible on the anterior surface of the ramus in accordance with the ascending buttress in accordance with the restored anatomy of the mandible (Fig. 3).

Another support of the “clasp ladder” for the posterior edge of the mandibular ramus was modeled along the posterior edge of the condylar process and the mandibular ramus. The crossbars of the “clasp ladder” were modeled taking into account the course of the osteotomy line and the anatomy of the mandibular nerve canal so that the osteotomy line remained between the crossbars, the distance from the first crossbar to the osteotomy line was at least 2 mm and there were 2 fixation points (2 holes each) with each side of the osteotomy line, the angle between the supports and crossbars was 90° (Fig. 4).

The support of the other “ladder” was modeled parallel to the coronoid notch of the mandible, departing from its edge by at least 2 mm, and 1 fixation point (1 hole) was formed on each side of the osteotomy line at a distance of at least 2 mm, and its crossbars were modeled on the same levels of the common support as the crossbars of the “clasp ladder” for the posterior edge of the lower jaw branch at an angle of 90° to the common support (Fig. 5).

The joints of the supports and crossbars of the “stairs”, repeating the relief of the restored anatomy of the lower jaw, were smoothed to increase the area of their intersection. At the intersection points of the supports and rungs of the “stairs,” holes for fastening with screws were modeled. The proposed device was manufactured by laser sintering of titanium powder followed by surface treatment. Disinfection and sterilization of the device was carried out before surgery.

Surgical protocol: under endotracheal anesthesia, a linear skin incision was made in the right retromaxillary region L = 3.5 cm, 1.0 cm from the posterior edge of the mandibular branch. The skin and subcutaneous fat were dissected in layers. The capsule of the parotid salivary gland was dissected, the soft tissues of the parotid salivary gland were bluntly and sharply passed through, the branches of the right facial nerve in the surgical wound were not visualized, the fascia and the masticatory muscle itself were dissected to the bone. The branch of the lower jaw was skeletonized to the neck of the condylar process and the base of the coronoid process, the deformation of the lower jaw was visualized, in which the consolidated fragments of the condylar process occupy an incorrect position - the articular process is displaced outward and anteriorly, the head is located on the posterior slope of the articular tubercle. An osteotomy was performed along the “old” fracture line using a piezosurgical device. The fragments were reduced to the correct position: a tight fit of the posterior edge of the condylar process and the ramus of the mandible to the “clasp ladder” of the reconstructive plate was visualized, as well as a congruent fit of the plate to the ramus of the mandible and the condylar process over the entire area of contact. The bite was restored, intermaxillary fixation was performed using orthoscrews in the oral cavity. The device itself is fixed with screws. Visual control of the position and stability of fragments and the device, vertical and transversal movements of the lower jaw was carried out. The soft tissues of the surgical wound were sutured in layers, and an aseptic dressing was applied. The postoperative period passed without complications. The sutures were removed on the 7th day. The intermaxillary traction was removed and the orthoscrews were removed on the 10th day. On the control X-ray examination, the fixation was stable (Fig. 6 a, b).

Claims (1)

A device for surgical treatment of deformity in the area of the base of the condylar process of the mandible in the form of a curved perforated body, repeating the correct anatomical shape of the mandible in the area of deformation, characterized in that it is made according to computed tomography data of a specific patient and consists of anterior and posterior halves with a common supporting part , made in accordance with the projection of the ascending buttress of the lower jaw, both halves have a cellular structure, while the posterior half is formed in accordance with the posterior part of the condylar process of the lower jaw, formed by vertical supports and horizontal crossbars, taking into account the course of the osteotomy line and the anatomy of the mandibular nerve canal so, so that the osteotomy line remains between the crossbars, the anterior half is formed with a support parallel to the coronoid notch of the lower jaw, the crossbars of both halves, in relation to the common support, are formed at the same levels at an angle of 90°, the joints of the supports and crossbars are smoothed, and at the points of intersection of the supports and crossbars there are holes for fastening the device with screws.