Extraoral approach for vertical osteotomy of the ascending mandibular ramus

Oral approach for mandibular ascending vertical osteotomy for surgical correction of mandibular deformities. Curing disease: Indication Oral approach for mandibular ascending branch vertical osteotomy for mandibular ascending branch osteotomy is suitable for mandibular deformity, mandibular deformity, small jaw deformity, partial jaw deformity, first arch syndrome and other maxillofacial deformities Common surgery. Preoperative preparation 1. X-ray cranial positioning piece measures the relationship between mandible and skull base plane, ear plane and jaw plane, determines the way of ascending branch osteotomy, moving distance and direction, and performs paper-cutting to predict the degree of postoperative deformity correction. 2. Model surgery transfers the joint and intraoral occlusal relationship to the Korean jaw. The sawing study model rearranges the occlusal relationship of the upper and lower jaw teeth, and observes the moving distance of the osteotomy block in the three-dimensional space of up, down, front, back, and left and right. 3. Plate making, on the basis of model surgery, the self-condensing plastic is used to make the jaw plate. 4. On the basis of the preoperative fixed appliance, the arch wire is bent into a hook plate with a feasible intermaxillary traction and ligated and fixed. Or a band loop on the canines on both sides of the upper and lower jaws and the teeth on the second molars, and the hook plate is placed and the splint is respectively ligated on each tooth for the intraoperative and postoperative operation of the jaw including the jaw plate. fixed. Surgical procedure Incision and approach Arc incision in the submandibular region, incision of the skin, subcutaneous tissue and platysma, cutting the submandibular gland capsule, flipping up the tissue flap, ligating the external maxillary artery and the anterior vein at the lower edge of the mandible, paying attention to protecting the mandibular branch of the facial nerve . 2. Reveal the lateral surface of the mandibular ascending branch The periosteum and the chewing muscle were cut at the lower edge of the mandible, and the chewing muscle was lifted under the periosteum until the sigmoid notch. 3. Ascending vertical osteotomy Place the deep hook on the sigmoid notch. Used for a saw or swing saw to vertically saw the rear 1/3 junction of the lift. 4. Bone fixation After reconstructing the occlusion relationship according to the design requirements and the plate record, the two bone pieces were re-fixed with the micro-plate screws. 5. Stitching The muscle periosteum, platysma and skin were layered and the semi-tube drainage strips were placed. complication Airway obstruction Acute obstruction of the respiratory tract and even suffocation are the most serious complications. During general anesthesia, due to vomiting aspiration, secretion obstruction, improper position, tongue fall, tracheal edema after tracheal intubation, and subsequent local tissue edema, plus intermaxillary fixation and other factors may cause respiratory obstruction. Measures should be taken to prevent it from happening. Close observation of the condition and elimination of factors that may cause acute obstruction of the respiratory tract. If signs of dyspnea appear (such as nasal agitation, three concave signs, etc.), it should be treated in time to prevent the occurrence of asphyxiating complications. 2. Bleeding Intraoperative injury to larger blood vessels can cause more serious bleeding, such as the maxillary LeFortI osteotomy when the internal maxillary artery or the aorta is injured, and the mandibular ascending branch is used to damage the inferior alveolar artery. Therefore, in the LeFortI type osteotomy, the osteotome can not be placed too high during the process of breaking off the distal end of the maxilla and the wing, and the direction of the incision cannot be upward to prevent damage to the internal artery of the jaw. When cutting the inner wall of the maxillary sinus, care should be taken to avoid damage to the aorta near the posterior end. It is often possible to use a bone knife to cut the bone and not to reach the trailing edge while retaining part of the bone to avoid accidental injury to the aorta. After the maxilla is broken down by the technique and the instrument, the posterior bone is trimmed. When the mandibular ascending branch is sagittal and osteotomy, the osteotome should not be too deep to avoid damage to the inferior alveolar artery. After the ascending branch is opened by the "cracking" method, the bone piece is opened and the bone piece is opened. Deeply repair the bone under direct vision. When the mandibular ascending longitudinal osteotomy (vertical or oblique osteotomy) is performed, the osteotomy line should remain behind the mandibular hole to prevent damage to the inferior alveolar artery. 3. Nerve damage For example, the mandibular nerve may be accidentally injured in the sagittal split osteotomy of the mandibular ascending branch. Precautions during osteotomy are the same as prevention of damage to the inferior alveolar artery. When the osteotomy and the moving bone segment are completed for fixation, care should be taken to avoid the occurrence of postoperative nerve injury symptoms caused by the compression of the inferior alveolar nerve by the bone segment. 4. Segmental necrosis The reason is mostly caused by excessive peeling of soft tissue or damage to the supply of blood vessels. Therefore, the separation and exposure of the bone surface should not be too large, especially in the distal heart segment (the bone segment near the gingival direction), the surface soft tissue should not be excessively separated, but the soft tissue should be kept as much as possible to maintain blood circulation and ensure bone. Healing. 5. Damaged root tip and pulp necrosis Because the transverse osteotomy line is too low (too close to the cutting edge or Face) causes the roots to be cut off at the same time. Therefore, the possible position of the root tip should be judged. The method includes: preoperative photographing of the X-ray film to detect the position and length of the root, and referring to the data of the normal normal root length, the intraoperative observation shows that the alveolar bone surrounded by the root has a slight elevation. After estimating the root length and the position of the root tip, a transverse osteotomy line is designed in the telecentric direction of the root tip of 4 to 5 mm (the maxilla is above the apex of the maxillary root and the mandible is below the root tip of the mandible). 6. Unconnected bone or poor bone healing Mainly due to poor fixation, insufficient contact of the bone segment, and poor blood supply. Therefore, the bone must be well fixed during and after surgery. Generally, inter-bone fixation (ligation fixation or micro-plate strong internal fixation) is used, supplemented by intermaxillary fixation, suspension fixation, and external stent fixation. In addition, the osteotomy design should consider maximizing the contact wounds when the bone segments (blocks) are connected, and prevent excessive peeling of the soft tissue and the like during the operation.