Arteriovenous malformation of the mandible is a rare and life-threatening lesion. The gold standard treatment is to extirpate the lesion surgically after endovascular embolization. Preoperative endovascular embolization is widely accepted, but there are limitations to the treatment. The authors introduce a technique in which the lesion is divided into parts and filled with bone wax, then curetted step by step. This gradual curettage method is effective and could be used instead of the standard treatment especially in hospitals with limited facilities for endovascular embolization.
Arteriovenous malformations (AVMs) of the mandible are rare in clinical practice. Often they are found by chance when teeth in the area are extracted. Under these circumstances, bleeding is unavoidable and may be life-threatening. If there is no obvious trauma, the lesion may grow slowly, destroying the surrounding tissue, and bleeding may occur at any time.
The gold standard treatment for AVM is to extirpate the lesion surgically after endovascular embolization, but many hospitals do not have the equipment to carry out presurgical embolization. The authors introduce a surgical technique that does not require presurgical embolization. The result is satisfactory and the authors think it will be helpful to hospitals that do not have the equipment for presurgical embolization.
Materials and methods
The operation should be performed under general anaesthesia. Before AVM treatment begins, temporary ligation of the external carotid artery is used to reduce possible bleeding.
On the surface of the mandibular lesion, where the mucosa and the buccal cortex are completed, a cut is made along the buccal alveolar bone. The soft tissues are carefully elevated from the surface of the bone until a bony window is reached, when the bleeding begins.
The bleeding must be controlled rapidly by applying digital pressure over the hole. Simultaneously, 0.5–1.0 cm plugs of bone wax are pushed into the bone cavity or AVM through the bone window until the bleeding ceases. The bony window is extended with rongeurs or a bur along the lesion, according to the panoramic radiograph and the operator’s practical judgement.
The height of the cortices of the bony cavity is then slightly reduced to facilitate visual and mechanical access. As the bony window is amplified more bleeding occurs, and more wax is used to control the bleeding. When a corner or a part of the lesion is completely filled with wax, there is usually no further obvious bleeding and the local lesion and wax can be curetted along the bone cavity. Amplification of this bony window continues, using wax to control the bleeding. The curetted wax can be re-used to pack other areas of the cavity. This procedure is repeated until the entire lesion is removed and the involved teeth are extracted. After curettage of the lesion, contouring is performed with burs.
The main artery feeding the lesion (e.g. inferior alveolar artery (IAA) or lingual artery) should be ligated to avoid relapse. The blood vessels can be determined using computed tomography (CT) angiography and can be found via the amplified bony window after curettage.
The ligation of external carotid artery is then relaxed to check whether there is bleeding in the bony window and on the surface of the bony wound. A slight haemorrhage is acceptable, but areas with obvious haemorrhage should be packed with wax and curetted again.
A 14-year-old boy presented to a hospital with pain in the right mandible; the diagnosis was pericoronitis of the wisdom tooth and he received anti-infection treatment, which was ineffective. Subsequently, in the authors’ hospital, it was found that the shape of the patient’s jaw and face was normal, and the left lower molar teeth were loose, but there was no haemorrhage or infection. An apparent blowing murmur could be heard through the stethoscope in the anterior region of the gonial angle. A panoramic radiograph confirmed the presence of a radiolucency in the left posterior mandible and the ramus ( Fig. 1 ). A CT scan revealed a cavity in the left mandible ( Fig. 2 ); slight gingival bleeding was present occasionally.
The patient was diagnosed with AVM of the mandible and intraoral curettage was advised. For more accurate diagnosis and treatment, a CT angiograph (CTA) was recommended to determine the size of the lesion and the condition of the artery. The operation was undertaken following the procedure described above.
According to the CTA, the IAA was the main feeding artery. In order to avoid relapse, the neurovascular bundle was found at the bottom of the cavity and ligation of the IAA at its proximal part, outside the mandibular foramen was carried out. A drainage tube was placed from the cervix incision to the bone cavity to avoid hematocele. The soft tissues were closed.
The patient recovered well after operation. There was little drainage and the tube was removed in 24 h. There was no bleeding and swelling in the surgical area. The appearance of the face was normal. A postoperative CT at 6 months showed that the continuity of the mandible was maintained although there is a bony defect ( Fig. 3 ). 1 year after surgery, the healing of the bony defect is satisfactory ( Fig. 4 ).