There is a mandible L in the upper part of the center of mandibular branch. In adults, the hole is approximately equivalent to the plane of mandibular molars, while in women, the hole is lower. There is a mandibular nerve groove behind the mandibular foramen, and the inferior alveolar nerve vascular bundle enters the mandibular foramen through this groove, which is the injection place of the inferior alveolar nerve intraoral block anesthesia. In the anterior lower part of mandibular foramen, there is a mandibular protuberance formed by the confluence of coracoid process and medial condyle. There are buccal nerve, lingual nerve and inferior alveolar nerve. Inject anesthetic into this protrusion and anesthetize these three nerves at the same time, so as to obtain anesthesia of one side of mandible, teeth and oral mucosa. A. Take the X-ray films of the forehead and curvature of mandible as the reference for mandibular classification and osteotomy.
B. Let the patient face the mirror, cover the lower part to be removed with the palms of both hands, analyze the types of mandibular angle hypertrophy with the patient, and the two sides reach an agreement on the surgical plan, including the scope of bone removal, whether to remove masseter muscle or buccal fat pad, etc. According to the shape and X-ray examination of mandible, mandible can be divided into three types, namely:
A. compound: people with the characteristics of the first two.
B. Eversion type: (front view) The mandibular angle is obviously outward, and the distance between mandibular angles exceeds the distance between cheekbones.
C. Back convex type: (side view) The mandibular angle is downward and backward convex, and the angle is often less than 1 10. A. Osteotomy: With the help of a light guide retractor, mark the mandibular angle with a pencil according to the preoperative prediction. Obliquely cut the outer plate of mandibular angle with crown eagle swing saw, and split the outer plate with bone chisel to make it thinner. For the kyphosis type, the inner and outer plates are cut by arc full thickness, and the mandibular angle is cut off full thickness; For the compound type, the combined osteotomy method of arc full-thickness osteotomy first and then thinning the outer plate was adopted.
B. Masseter muscle and buccal fat pad: if masseter muscle is hypertrophy, the posterior inferior masseter muscle should be thinned; For those whose cheeks are too plump, remove the buccal fat pad.
C. postoperative treatment: compression fixation with elastic bandage. Change the elastic jaw support after 5 days, and remove the stitches after 7 days. Follow the clue to 2w.
D. Local nerve block anesthesia: 2% lidocaine and1:200,000 epinephrine were used as anesthetics. Open your mouth wide, behind the molars, and the tip of the buccal fat pad is slightly outside the center of pterygomandibular fissure as the insertion point. Put the syringe between the 1 and the second bicuspid teeth of the opposite mandible, push it forward about 2.5cm, that is, reach the inferior alveolar nerve groove inside the mandibular ramus, and there is no blood withdrawal, then inject the alveolar nerve under the anesthesia of 1.5 ~ 2.0 ml anesthetic, and then retreat the needle to the muscular layer.
E. local infiltration anesthesia: in order to strengthen the anesthesia effect, percutaneous needle puncture was performed at the mandibular angle, close to the bone surface, and infiltration anesthesia was performed from the periosteum to the masseter and medial pterygoid muscle attachment area. Make an incision in the mouth from the lower front edge of the mandibular branch to the buccal gingival sulcus to the second bicuspid, all the way to the periosteum. The periosteum of the middle and lower segment of the lateral plate of the mandibular branch and the mandibular body, especially the mandibular angle and the lower edge of the mandibular angle, were completely peeled off under the periosteum without exposing the mental nerve.