Highly oblique sagittal osteotomy guide device

Abstract

High oblique sagittal osteotomy (HOSO) guide device, comprising the following: I. Right and left arms, parallel to each other a. With a plug-in mechanism to secure the back of the arms behind the mandibular ramus, b. With angled guide strips for a cutting angle tailored to each patient, c. wherein the left arm consists of a flexible sleeve that facilitates the positioning of the arms around the lower jaw.

Description

Field of invention

[0001] The present invention relates to the field of orthognathic surgery. Background of the invention

[0002] Orthognathic surgery is a surgical technique used to correct malocclusions caused by mandibular prognathism, retrognathia, open bite, and asymmetries. 1 This treatment has a significant impact on the function of the stomatognathic system, improving various aspects such as nutrition and digestion, speech, periodontal disease, and lip incompetence. Changes in facial contours and aesthetics can also be observed, which has a major influence on the psychological development of patients. The most commonly used surgical design is the bilateral sagittal split osteotomy (BSSO). 2An alternative to the BSSO is the high oblique sagittal osteotomy (HOSO), which was originally called the Schlössmann osteotomy. 3 The HOSO procedure is performed intraorally and consists of a 45° angled osteotomy of the ascending mandibular ramus, ending above the alveolar foramen. 4,5 The most important described advantages of the HOSO technique include, for example, the simplicity of the operation, which facilitates learning, the reduced risk of neurosensory changes due to greater protection of the inferior alveolar nerve compared to the BSSO, and the impairment of temporomandibular joint function. 6 .

[0003] A recent computer study investigated the influence of the osteotomy angle during HOSO (hoof-overhead orthognathic surgery) on the stress distribution between the osteosynthesis plates and mandibular segments. The results showed that the osteotomy angle is a highly relevant parameter in planning orthognathic surgery, as the stress distribution is significantly affected by changes in the angle. Additionally, the resulting surface contact between bone segments varies depending on the osteotomy angle, increasing by 44.67% from 45° to 70° and decreasing by 22.05% when the angle is reduced to 30°. 7Furthermore, factors such as the anatomy of the mandible or the patient's physiological conditions can determine the minimum necessary contact area between bone segments to avoid impairing osteosynthesis. Therefore, the purpose of the invention is to provide an adjustable guide for the HOSO to accelerate the intraoperative procedure.

[0004] Further prior art is known as: DE 34 47 163 A1 and DE 60 2004 000 868 T2.

[0005] According to the aspect of the present invention, the method for guiding the high oblique sagittal osteotomy (Problem 1) comprises the following steps: (a) exposing the required mandibular bone structure; (b) fixing the positioning element and stabilizing support to the mandible; (c) assembling the anterior and posterior housings; (d) assembling the two arms to the previously fixed anterior and posterior housings; (e) assembling and securing the guide device by assembling the plug-in mechanism of the adjusting arms behind the ramus; (f) guiding the split by adjusting the desired cutting angle using the angle guide element from the guide device and then tightening the threaded nut to prevent the angle guide element from moving; (g) cutting the bone using the angle produced by the two faces of the adjustable arms;(h) Disassemble the insertion mechanism of the adjusting arms and remove them by pulling them out of the guides of the front and rear housings; (i) Unscrew and remove the stabilizing support together with the front and rear housings. This method can also be used in the case of a bilateral high oblique sagittal osteotomy.

[0006] According to another aspect of the present invention, a method for reducing the average time of orthognathic HOSO surgery is provided (Problem 2). The method comprises the following steps: (a) performing prior surgical planning according to the standard safety protocols for orthognathic surgery; (b) defining the desired angle prior to the operation; and (c) selecting the length of the adjusting arms according to the intraoral anatomy. This method can significantly reduce the average time of orthognathic HOSO surgery using the HOSO guide device.

[0007] According to another aspect of the present invention, a method for increasing reproducible results is provided (Problem 3). This method comprises the following steps: (a) Checking the accurate leveling of the stabilizing support during the drilling operation. (b) Checking the correct calibration of the angle guide element before the operation. This guarantees the desired cutting angle in every case.

[0008] Another aspect involves a procedure to reduce the cost of orthognathic HOSO surgery (Problem 4). This method includes the following steps: (a) using the HOSO guide device instead of expensive custom surgical guides; (b) disinfecting all components of the HOSO guide device after surgery and reusing it like any other reusable surgical instrument.

[0009] The foregoing summary serves only for illustration and is in no way intended to be limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent with reference to the drawings, the following detailed description, and the following claims. Subject matter of the invention

[0010] The HOSO guide device can be used to treat patients undergoing orthognathic HOSO surgery. The guide device significantly reduces the likelihood of unfavorable clefts, while simultaneously reducing the average time of orthognathic HOSO surgery, increasing the probability of reproducible results, and lowering the cost of orthognathic HOSO surgery. Objectives of the invention

[0011] The present invention aims to solve five (5) problems: 1. Performing the oblique sagittal osteotomy. 2. Reduction of the average time of the HOSO operation. 3. Increase in reproducible results. 4. Reduction of the costs for the HOSO operation. Specific description

[0012] The HOSO guide consists of a variable, angled positioning element (1) located between the stabilizing support (2), which supports the HOSO guide against the mandibular teeth, and the lower part of the housing (3). The head of the positioning element is angled to adjust the horizontal angle of the osteotomy. The positioning element rests on the stabilizing support and extends through the central opening of the lower housing part to provide structural rigidity. The connection is established by the magnet (2.1) of the stabilizing support and the magnetic fitting (4) in the front housing (5) and the rear housing (6). Fig. ).

[0013] The front housing has an angled guide strip for the left arm (5.2) and a guide hole for the right arm (5.3). The rear housing (6) has an angled guide strip for the left arm (6.1) and a guide hole for the right arm (6.2), which serve as guides and provide stability for the right arm (7) and the left arm (8). The complete left angled guide strip, which is adapted to the front and rear housings, allows the cutting angle required for the HOSO osteotomy to be individually adjusted for each patient in the range of 30 to 70°. The cutting guide strip (7.1) is located longitudinally along the right arm. At the end of the right arm is a plug (7.2) that fits into (8.2) the socket of the left arm. The right arm can only be rotated around its own axis. The cutting guide strip (8.1) is located longitudinally along the left arm. At the end of the left arm is a socket (8.2) that fits into (7.2) the plug from the right arm fits. A flexible sleeve (8.3) served as a bridge between the segment of the left arm with the cutting guide strip and the left arm (8.4). The flexible sleeve allows the arms to be positioned around the mandible. By manipulating the left arm, the cutting angle between the cutting guide strips of the right and left arms can be adjusted. The synchronized movement between the left and right arms is controlled by the angle guide element (9). Fig. The angle guide element (9) is mounted on the front of the front housing using the left arm, the right arm, and the threaded bolt of the front housing (5.1). The angle guide element only allows the angular displacement amplitude for which it was designed. After assembly, the angle guide element is positioned according to the required cutting angle. When the desired angle is reached, a threaded nut (10) is used to prevent the angle guide element from moving. The threaded nut is tightened with the threaded screw from the front housing ( Fig. The HOSO guide device can be manufactured in various sizes and materials. Brief description of the drawing Fig. Figure 1 is a frontal view showing the HOSO guide device. Fig. Figure 2 is a half-section view of the HOSO guide device. Fig. Figure 3 is an isometric lower right view of the HOSO guide device. Fig. Figure 4 is an isometric upper right view of the HOSO guide device. Fig. Figure 5 is an isometric rear view of the HOSO guide device. Fig. Figure 6 is an isometric upper left view of the HOSO guide device. Cited non-patent literature 1. Kuehle R, Berger M, Saure D, Hoffmann J, Seeberger R. High oblique sagittal split osteotomy of the mandible: assessment of the positions of the mandibular condyles after orthognathic surgery based on cone-beam tomography. Br J Oral Maxillofac Surg. 2016;54(6):638-642. doi:10.1016 / j.bjoms.2016.03.017 2. Böckmann R, Meyns J, Dik E, Kessler P. The modifications of the sagittal ramus split osteotomy: A literature review. Plast Reconstr Surg - Glob Open. 2014;2(12):1-7. doi:10.1097 / GOX.0000000000000127 3. Herrera-Vizcaíno C, Herrera Vizcaino M, Pelliccioni O. Biomechanical simulation of different bone fixation methods with osteosynthesis material used in Schlössmann modified osteotomy. XIII Congr Int Metodos Numéricos en Ing y Ciencias. 2016;XIII:113. 4. Landes C, Tran A, Ballon A, Santo G, Schübel F, Sader R. Low to high oblique ramus piezoosteotomy: A pilot study. J Cranio-Maxillofacial Surg. 2014;42(6):901-909. doi:10.1016 / j.jcms.2014.01.008 5. Kaduk WMH, Podmelle F, Louis PJ. Revisiting the Supraforaminal Horizontal Oblique Osteotomy of the Mandible. J Oral Maxillofac Surg. 2012;70(2):421-428. doi:10.1016 / j.joms.2011.02.027 6. Herrera-Vizcaino C, Seifert L, Berdan M, et al. Revision of 116 orthognathic surgery patients operated on with the high-oblique sagittal osteotomy (HOSO): a retrospective case series (PROCESS-compliant article). Clin Oral Investig. 2020. doi:https: / / doi.org / 10.1007 / s00784-020-03653-2 7. Herrera-Vizcaino C, Baselga Lahoz M, Pelliccioni Monrroy O, Udeabor E S, Robert S, Lukas Benedikt S. Stress distribution is susceptible to the angle of the osteotomy in the high oblique sagittal osteotomy (HOSO): biomechanical evaluation using finite element analyses. Comput Methods Biomech Biomed Engin. 2020;0(0):1-9. doi:10.1080 / 10255842.2020.1810242

Claims

[1] High oblique sagittal osteotomy (HOSO) guide device comprising: I. Right and left arms, parallel to each other a. With a plug-in mechanism to secure the back of the arms behind the mandibular ramus, b. With angled guide strips for a cutting angle tailored to each patient, c. wherein the left arm consists of a flexible sleeve that facilitates the positioning of the arms around the lower jaw. [2] A magnetic positioning element a. wherein the head of the magnetic positioning element is angled and this angle can range from 0° to 30° with respect to the central axis, b. with a magnetic adjustment mechanism that stabilizes the housings. [3] A stabilizing support a. With a design that allows adaptation to the anatomy of the lower jaw to generate support for the housing. b. With a magnet on the surface to provide stability to the positioning element. [4] A front and rear housing that serves as a guide for mounting the right and left arms. a. With a curved strip that allows the angle of the osteotomy to be changed in a range of 30° to 70°. b. wherein a threaded bolt and a threaded nut prevent the angle guide element and the arms from moving.

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