# Complicated Mandible Fracture Treatment with Xenogenic Bone Graft
## 2 Materials and Methods  
The present case report followed the CARE guidelines. Patient, 39 years old, female (height--178 cm, weight--58 kg), was admitted to the Department of Maxillofacial Surgery of Sechenov University, with complaints of pain on the left side of the mandible, swelling of the left cheek, limited mouth opening, and malocclusion. An extraoral physical exam revealed altered facial configuration due to soft tissue edema in the left buccal, parotid, and submandibular regions. The skin color was physiological. Pain and fragments of mobility at the left mandibular angle were noted during palpation. Regional lymph nodes were not enlarged. The mouth could open less than 20 mm. There was no evidence of dysphagia. During intraoral checkup, lacerations and swelling of the mucosa around the left third lower molar were noted; the crown of the tooth was grossly decayed. Swallowing was free and painless. The occlusion was significantly altered due to fragment dislocations. The orthopantomogram showed a fracture line in the area of tooth 3.8 and an oval-shaped area of radiolucency with teeth 3.7 and 3.8, with root involvement (Figure 1). After a primary checkup and radiological evaluation, intermaxillary fixation was performed; the bite was stabilized with a physiological occlusion using arch bars and rubber elastics. The patient was examined in a standard pre-surgical volume, using laboratory (blood and urine tests) and instrumental (EKG and chest X-ray) studies. Multi-spiral computed tomography of the lower jaw determined an oval-shaped bone lesion at the root level of teeth 3.7 and 3.8, with dimensions of 20 \(\times\) 16 \(\times\) 16 mm. The bone was swollen at the level of teeth 3.6-3.8, a periosteal reaction was noted, the contours of the jaw were enlarged, and the cortical plates were thinned. Pathological fracture of the lower jaw, with fragment displacement, occurred; the fracture line passed through the sockets of teeth 3.7 and 3.8 (Figure 2). Under general anesthesia (nasotracheal intubation), the patient underwent extraction of teeth 3.6, 3.7 and 3.8, cystectomy, and osteosynthesis. The angular fracture of the lower jaw was reduced and stabilized with two 6-hole titanium bone mini-plates and 10 mm mini-screws (\"Connet\", Moscow, Russia). The bone defect was filled with xenograft \"Collost\" (\"BIOPHARMHOLDING\", Moscow, Russia). The external approach was chosen due to the prolonged violation of the integrity of the mucosa in the area of the fracture line, as well as the need to remove the cyst, reposition the fragments of the lower jaw, and fix them. The patient was treated with \"Collost\" osteoporropic material (xenogenic collagen osteotropic material, type I, with a 3D structure, obtained from the skin of cattle; \"BIOPHARMHOLDING\", Moscow, Russia). We used this material in the following 2 forms: 2 spheres (each 8 mm in diameter) and a membrane (30 \(\times\) 20 \(\times\) 3 mm in size). According to the manufacturing company's instructions, the material was sterilized with all necessary methods for biological materials, and, in addition, with \(\gamma\)-radiation from a flacon. Before implantation in the wound, the material was placed in sterile saline at 25 \({}^{\circ}\)C for 15 min; the average volume increased by 20% for both the spheres and membranes. Figure 1: Orthopantomogram before surgery. Figure 2: Patient’s CBCT at admission. A bone cyst, 20 \(\times\) 15 mm in size, was determined. Cystectomy was performed and small bone fragments, d = 3 \(\times\) 5 mm, were removed (Figure 3b). Stage 2. After preliminary marking, an incision was made in the submandibular region on the left, departing from the edge of the lower jaw by 2.0 cm, up to 2.5 cm long. The skin and subcutaneous fatty tissue were dissected in layers, m. platysma, the own fascia of the neck.