Method for preventing the formation of marginal defects of the lower jaw in the osteotomy area during orthognathic surgery

Abstract

FIELD: medicine; maxillofacial surgery.SUBSTANCE: invention is intended for use in orthognathic surgery. An incision is made in the mucous membrane of the lower arch of the oral cavity, 0.5 cm from the edge of the attached gingiva, from the projection of tooth 3.5 to the middle third of the pterygoid fold on the left and from the projection of tooth 4.5 to the middle third of the pterygoid fold on the right. Skeletalisation of the outer and inner surfaces of the body and branches of the lower jaw on the right is performed, and osteotomy of the cortical plate of the inner surface of the lower jaw branch on the right is performed using a bur. Next, the osteotomy continues downwards on the body of the lower jaw on the right, parallel to its oblique line, and the cortical plate of the outer surface of the body of the lower jaw on the right is cut . Then, the body and branch of the lower jaw on the right are split along the osteotomy lines. A similar procedure is performed on the body and branch of the lower jaw on the left. Thus, the distal fragment of the lower jaw is mobilised. A custom-made stereolithographic template is placed on the occlusal surface of the upper and lower jaw teeth, and wire ligature intermaxillary fixation is performed, thus placing the distal fragment in the pre-planned position. The right proximal fragment of the lower jaw is positioned. Next, passive fixation of the osteotomised fragments of the lower jaw is performed using two mini-plates and eight mini-screws, with one of the mini-plates being placed and fixed along the edge of the lower jaw. A similar procedure is performed on the opposite side. Then, fragmentation and modelling of the allogenic iliac bone block is performed, taking into account the size and shape of the defects formed in the osteotomy areas. The resulting blocks are placed in the defect areas of the mandible on both sides.EFFECT: prevention of marginal defects of the lower jaw in the osteotomy area resulting from mandibular displacement during orthognathic surgery, thereby increasing aesthetic satisfaction with the outcome of surgical treatment.1 cl, 3 dwg, 1 ex

Description

[0001] The invention relates to the field of medicine, namely, to maxillofacial surgery and is intended for use in performing orthognathic surgery.

[0002] Bilateral sagittal split osteotomy (BSSO) of the mandible can be performed as a standalone surgical procedure or as part of a bimaxillary orthognathic surgery to achieve mandibular advancement. With significant mandibular displacement, consolidation of the mandibular fragments may be accompanied by the formation of a visual and palpable marginal defect of the mandible in the area of ​​the osteotomy, which alters the contour of the mandible and reduces aesthetic satisfaction with the surgical outcome.

[0003] A known method for modifying bilateral sagittal split osteotomy of the mandible, in which the vertical osteotomy of the outer surface of the mandible is performed to a level of 0.5-0.8 cm from the edge of the mandible, and the horizontal osteotomy of the outer surface of the mandible is performed in the anteroposterior direction, along the edge of the mandible, retreating 0.5-0.8 cm from it. After splitting the fragments, the angle of the mandible completely remains as part of the distal fragment of the mandible, which helps maintain the continuity of the edge of the body of the mandible [Mont'Alverne ALF, Xavier FG, Meneses A M, Santos E S, Franco J M P L. Is Bilateral Sagittal Split Osteotomy of the Mandible With No Step Possible? A Modification in the Technique. J Craniofac Surg. 2019 Oct;30(7):2275-2276].The disadvantages of this method are the high risk of an uncontrolled fracture of the lower jaw in the absence of experience of the surgeon and the limitation of the extension of the maxillomandibular complex due to technical difficulties in fixing the fragments and the high risks of their unsatisfactory consolidation.

[0004] A method for performing bilateral sagittal split osteotomy of the mandible modified by Epker with simultaneous elimination of the resulting defects of the mandible in the osteotomy area using an autograft from the iliac crest is known [Raffaini M, Magri A, Giuntini V, Nieri M, Pantani C, Conti M, How to Prevent Mandibular Lower Border Notching Following Bilateral Sagittal Split Osteotomies or Major Advancements: Analysis of 168 Osteotomies, Journal of Oral and Maxillary Surgery, 2020]. The disadvantage of this method is the need for intervention in the donor area, which carries the risk of intra- and postoperative complications.

[0005] The objective of the claimed method is to eliminate the above mentioned disadvantages and to develop a simple and reliable method for preventing the formation of a marginal defect of the lower jaw in the osteotomy area.

[0006] The technical result of the claimed method is achieved by performing a bilateral sagittal split osteotomy of the mandible and fixing the distal fragment of the mandible in the planned position. The proximal fragments of the mandible are positioned and passively fixed. Fixation is achieved using two miniplates on each side, with one miniplate placed and secured along the margin of the body of the mandible on both sides. The allogeneic ilium block is then fragmented and modeled, taking into account the size and shape of the resulting defect in the osteotomy area. The resulting block is then installed into the defect area of ​​the mandible on both sides.

[0007] The claimed method is illustrated by drawings. Figure 1 is a schematic representation of the mandible fragments after performing a bilateral sagittal split osteotomy and fixing the distal fragment of the mandible in the planned position, where 1 is the mandible defect in the area of ​​the osteotomy. Figure 2 is a schematic representation of the mandible after fixation of the osteotomized fragments, where 2 are mini-plates and mini-screws. Figure 3 is a schematic representation of the mandible after eliminating the resulting defect in the osteotomy area with an allogeneic bone block, where 3 is the allogeneic bone block.

[0008] The method is carried out as follows: in an operating room, under combined endotracheal anesthesia, after antiseptic treatment of the surgical field, infiltration and mandibular anesthesia on both sides with an articaine solution with the addition of an epinephrine solution at a concentration of 1:200000, an incision is made in the mucous membrane of the lower fornix of the vestibule of the oral cavity, 0.5 cm from the edge of the attached gum, from the projection of the tooth 3.5 to the middle third of the pterygomaxillary fold on the left and from the projection of the tooth 4.5 to the middle third of the pterygomaxillary fold on the right. Skeletonization of the outer and inner surfaces of the body and branches of the lower jaw on the right is performed, an osteotomy of the cortical plate of the inner surface of the branch of the lower jaw on the right is performed using a bur. Then the osteotomy continues downwards onto the body of the lower jaw on the right parallel to its oblique line, a cut is made in the cortical plate of the outer surface of the body of the lower jaw on the right.Next, the body and ramus of the mandible on the right are split along the osteotomy lines. A similar procedure is performed with the body and ramus of the mandible on the left. This mobilizes the distal fragment of the mandible. A custom-made stereolithographic template is placed on the occlusal surfaces of the teeth of the upper and lower jaws, and wire ligature intermaxillary fixation is applied, thereby positioning the distal fragment in the pre-planned position. The right proximal fragment of the mandible is positioned. Next, passive fixation of the osteotomized fragments of the mandible is performed using two miniplates and eight miniscrews, with one of the miniplates positioned and secured along the edge of the body of the mandible. A similar procedure is performed on the opposite side.The allogeneic iliac bone block is then fragmented and shaped, taking into account the size and shape of the resulting osteotomy defects. The resulting blocks are then placed in the defect areas of the mandible on both sides. The orthognathic surgery proceeds as usual.

[0009] Clinical case 1. Patient M., 25 years old. Admitted to the hospital with the diagnosis: "Combined deformation of the jaws, skeletal dysgnathia class II." Complaints on admission: difficulty biting and chewing food. Medical history: malocclusion has been noted since early adolescence. Consulted with a maxillofacial surgeon and orthodontist, comprehensive orthodontic and surgical treatment was recommended. Decompensation of the dentition was performed as part of orthodontic preparation for the surgical stage of treatment. Objectively: general condition is satisfactory, consciousness is clear, position is active. Respiratory rate 16 bpm. Heart rate 70 bpm. Blood pressure 110 / 78 mmHg. Local status: facial configuration is unchanged, disproportion is noted due to insufficient projection of its lower zone due to lower micrognathia. When viewed from the front, the bridge, tip of the nose, philtrum and the lowest point of the chin correspond to the conventionally drawn line of the face.Upon examination in profile, the jaw base relationship is determined according to skeletal class II. From the oral cavity perspective, fixed orthodontic appliances (brackets) are fixed on the upper and lower dental arches. The relationship of the dental arches is determined according to Angle class II, as well as sagittal incisor disocclusion. In the operating room, under combined endotracheal anesthesia, the following surgical intervention was performed: "Bimaxillary orthognathic surgery." During the surgical intervention, after performing a bilateral sagittal split osteotomy of the mandible and applying intermaxillary ligature fixation, the proximal fragments of the mandible were positioned. Next, fixation of the osteotomized fragments of the mandible on the right was performed using mini-plates (x2) and mini-screws (x8); during fixation, the lower mini-plate was installed along the edge of the body of the mandible on the right. The fixation of the osteotomized fragments of the lower jaw on the left was carried out in a similar manner.Following the manipulations performed, mandibular defects measuring 16 x 11 x 5 mm on the right and 14 x 12 x 5 mm on the left were identified in the osteotomy area. The allogeneic ilium bone block was fragmented and modeled, taking into account the size and shape of the resulting defects in the osteotomy area. The resulting allogeneic bone blocks were installed in the mandibular defects on both sides. The postoperative period was uneventful. A multispiral computed tomography scan of the skull performed on the first postoperative day demonstrated satisfactory fixation of the mandibular fragments and the integrity of the bone blocks. The patient was discharged on the seventh postoperative day in satisfactory condition for outpatient follow-up.According to the multispiral computed tomography of the skull, 6 months after the operation, satisfactory consolidation of bone tissue was noted in the area of ​​the bilateral osteotomy of the lower jaw, the edge of the body of the lower jaw is clear, even on both sides, and no bone steps are detected.

[0010] The proposed technique is technically simple, does not require donor site damage, and prevents the formation of marginal defects of the mandible in the osteotomy area caused by mandibular displacement during orthognathic surgery, thereby increasing aesthetic satisfaction with the surgical outcome. The proposed method has been implemented at the Federal State Budgetary Institution National Medical Research Center "Central Research Institute of Maxillofacial Surgery" of the Ministry of Health of the Russian Federation in Moscow. Ten successful surgeries have been performed.

Claims

A method for preventing the formation of a marginal defect of the lower jaw in the area of ​​an osteotomy during orthognathic surgery, which includes performing a bilateral split osteotomy of the lower jaw followed by the application of intermaxillary fixation in the planned occlusion, positioning the distal fragments and passive fixation of the osteotomized fragments of the lower jaw using two mini-plates and eight mini-screws, in which the installation of one of the mini-plates is carried out along the edge of the lower jaw, characterized in that after fixation of the osteotomized fragments of the lower jaw, fragmentation and modeling of the allogeneic block of the ilium are carried out taking into account the size and shape of the defects formed in the area of ​​the osteotomy and the installation of the obtained bone allografts in the area of ​​the defects of the lower jaw on both sides.

Images