Treatment of intraosseous high flow arteriovenous malformation of the mandible by temporary segmental ostectomy for extracorporal tumour resection: a case report

We present a case of intraosseous arteriovenous malformation of the mandible with temporary segmental resection, extracorporal removal of the vascular malformation from the osteotomized mandibular bone and intraoperative osteosynthetic replantation of the avascular bony remnant. In a follow-up after 1 year, when removing the titanium miniplates used for osteosynthesis, the mandibular bone was found to have remodelled completely. There is no recurrence of the lesion in a follow-up after 2 years.

Observations on the vascular structure of malignant tumours of the mandible using specimen arteriography

OBJECTIVES

To investigate the vascular structure of different malignant tumours of the mandible.

METHODS

Specimen arteriography was performed on seven cases of squamous cell carcinoma of gingiva and four sarcomas.

RESULTS

Malignant tumours could be divided into two groups: (1) the hypervascular sarcomas in in which the arteries were dilated, distributed evenly and arranged in a bush-like pattern; and (2) hypovascular squamous cell carcinoma with scanty arteries distributed unevenly without dilatation; in some areas, the shape of arteries was irregular and arranged in a network pattern.

CONCLUSIONS

The variation in vascular structure of malignant tumours of the mandible may be related to the outcome of regional chemotherapy.

Oral complications associated with sickle cell anemia: a review and case report

Sickle cell anemia is a multisystem disease that can affect the oral region. This article reviews previously reported oral complications associated with this disease and describes the cause of these problems. A case history describes a patient with multiple oral problems after a sickle cell crisis. The diagnostic and management problems of this case are highlighted. The need for a multidisciplinary approach to the care of these patients is emphasized.

The multipoint contact plate in fracture treatment of the atrophied mandible: animal study and clinical application

Rapid consolidation of osseous fractures requires stable immobilization of the fragments. In the atrophied mandible, the nutrient supply should be ensured by protecting the periosseous soft tissue, i.e., the periosteum. In the conventional placement of osteosynthesis plates, however, the subimplant nutrition is restricted because of the high surface pressure between the osteosynthesis plate and bone. In order to improve the subimplant nutrient supply, we designed a new osteosynthesis plate with a "knobbed" underside enabling multipoint contact. Histomorphologic comparative studies were conducted on 16 Göttingen minipigs with an average weight of 47.5 +/- 8 kg. In each minipig, one side of the mandible was fractured and one side was left intact. One side of each mandible was plated with a six-hole dynamic multipoint contact plate and the other side with a conventional plate. The plates were applied, either epiosseous or epiperiosteal, with bicortical screws under defined torque. The results demonstrate the advantages of multipoint contact plates over the conventional ones and create the clinical basis for a "bio-logical" plate design that allows callus to grow between the knobs and therefore provide adequate nutritional and vascular supply. The plate's knobbed profile also promotes extraosseous venous drainage without impeding intraosseous fluid flow. This plate is the logical choice for rapid fracture consolidation in the high-grade atrophied mandible.

Bilateral cervicofacial arteriovenous malformations: a case report with unusual complications

Arteriovenous malformations (AVM) of the craniofacial region are complex problems that require a multidisciplinary approach. Early recognition and proper treatment are essential for an acceptable longterm outcome. This article describes the case of an improperly handled AVM. During the course of retreatment, the left external carotid artery was reanastomosed to gain access for embolization in an attempt to treat the patient definitively. There is also a discussion of classification theories of formation, contemporary treatment, and complications.

[Arteriovenous malformation of the mandible. Apropos of a case in a 6-year-old child]

Arteriovenous malformations of the mandible are uncommon. Though characteristic clinical and radiological presentations are well described, management in the case of children is still a matter of debate. We report a mandibular angioma in a 6-year-old girl which was treated with superselective embolization. This method is the treatment of choice for mandibular arteriovenous malformations in children because of the low complication rate and the preservation of healthy tissue. When the malformation continues to develop despite repeated embolizations, surgical treatment may be necessary.

Experimental evaluation and clinical use in the head and neck of a 3M/Precise microvascular anastomotic device

Microvascular reconstructions in the head and neck are usually long operating time procedures. Mechanical anastomotic devices help to reduce operating time and can reduce anastomotic failures avoiding foreign bodies in the lumen of the vessel. One of these systems is the 3M/Precise microvascular anastomotic device, it is a non-absorbable device, however, criticisms of this system have been directed to the fact that pulsation of the vessel wall against a rigid structure could lead to thinning of the vessel wall and aneurysm formation. No aneurysms have been found previously in other experimental models. Our experimental study on the aorta and vena cava of the rat comprises 25 arterial and 25 venous anastomoses. In the arteries, four proximal aneurysms were found, two of these were failures. In the venous anastomoses, no failures were found nor aneurysm formation. The system is very useful for performing clinical end to end venous anastomosis helping to reduce anastomotic failures. Aneurysms have been found in arteries although four different ring sizes were available. The device is less easy to use in them than in veins and sometimes can be difficult to apply, making manual suturing a better choice for clinical arterial anastomosis.

Tomographic studies of human jaws to assess potentials for preserving the blood supply in rim mandibulectomies

Rim mandibulectomy, resecting the aveolar segment of the mandible while preserving the inferior cortical arch, has been shown to be a biologically and surgically sound procedure. In order to study the surgical anatomy of the mandible and determine the reproducibility of the anatomic markers and neurovascular supply, we studied serial tomographic cuts of 50 living human mandibles (21 males, 29 females; ages 17 to 87). The dentition was complete in 13, partial in 30, and edentulous in 7. The review showed that the location of anatomic structures was symmetrical in all these adult patients regardless of age, sex, or extent of dentition. (The only significant difference was in the height of the alveolus, which was decreased in edentulous patients.) The data show that in performing a rim mandibulectomy, the blood supply may be preserved in most patients if at least 11 mm of vertical height is preserved of the inferior cortex of the body of the mandible.

Delay method of implantation enhances implant-bone binding: a comparison with the conventional method

This report compares the conventional and delay methods of implantation, evaluating the bone formation around a dense apatite implant. In the conventional method, the implant is placed immediately after the cavity is prepared. In the delay technique, the implant is placed 2 weeks after preparation. This study found that many new thin trabeculae and capillaries formed around the cavity during the delay period, while none had formed at the time of implantation using the conventional method. The delay method showed earlier and wider bone formation, and less surrounding fibrous encapsulation. These results indicate that the delay technique can be an efficient method for establishing good bone binding.

Anatomical study on valves of human facial veins

The valves of the facial veins of 39 sides from 20 cadavers, aged 54-95 years, were investigated. Anatomical study of the valves is important, because the facial veins can be used for microvascular anastomosis in reconstruction in the head and neck. The present study confirmed that valves existed in the human facial veins, and were most frequently observed around the lower border of the mandible. When valves were classified into 5 types according to the morphology of the lobules, bicuspid valves were the most common (93.5%), followed by traced valves (4.1%), valve preparation (1.3%), and unicuspid valves (0.9%). However, no tricuspid valves were observed. Valves appeared most often (82.9%) at confluences with the facial veins. The length of valves in the trunk of the facial veins was twice the size of the inner diameter of the vessels in 78.4% of the cases. Therefore, when valves were observed at the anastomosis sites, the present results indicated that these valves could be avoided by resecting a length of about twice the inner diameter.

Percutaneous internal maxillary arterial embolization with ethylcellulose microspheres. Results in an animal model

RATIONALE AND OBJECTIVES

To investigate the use of ethylcellulose microspheres as long-term and peripheral emboli for percutaneous maxillofacial arterial embolization.

METHODS

Eight mongrel dogs were selected randomly for internal maxillary artery embolization with ethylcellulose microspheres. After embolization, angiographic, microangiographic, and histologic examinations were performed.

RESULTS

Ethylcellulose microspheres were trapped in the peripheral arterioles from 24 hours to 6 months after embolization. Degenerative changes of maxilla, mandible, and dental pulp occurred after the embolization of the internal maxillary artery with the microspheres. No evidence of whole or focal necrosis of the bones and surrounding soft tissues was found between 24 hours and 6 months after embolization.

CONCLUSION

Ethylcellulose microspheres can be used as an alternative long-term and peripheral embolic agent, with potential for percutaneous maxillofacial arterial embolization.

Hypothermia and cardiopulmonary bypass during resection of extensive arteriovenous malformation followed by microvascular reconstruction

A patient is presented in whom hypothermic hypoperfusion and cardiopulmonary bypass were used to aid in resection of a mandibular arteriovenous malformation. This was followed by immediate microvascular reconstruction using a fibular osteocutaneous microvascular free tissue transfer. Prior attempted resection after highly selective embolization had proved inadequate. We found that the operative field, using hypothermic hypoperfusion was bloodless and enabled safe, rapid excision of the malformation. After patient rewarming, microvascular reconstruction was readily performed. No neurologic sequelae resulted, and no recurrence of the malformation has been noted.

Relationships between cellular condensation, preosteoblast formation and epithelial-mesenchymal interactions in initiation of osteogenesis

Initiation of osteogenesis or bone formation is dependent on cell and tissue interactions. We investigated the events between 4 and 7 days of incubation that translate epithelial-mesenchymal signalling into overt differentiation of osteoblasts and deposition of bone in the mandibles of chick embryos. Condensation of mandibular mesenchyme (the membranous skeleton), visualized with PNA-lectin, occurred at H.H. mid-26 (5.75 days), lasted 12 h and preceded osteoblast differentiation by 1.5 days. As determined from 3D-reconstruction all mandibular membrane bones arose from a single condensation closely associated with the stomodeal epithelium. The finding that the osteogenic condensation in the mandibular arch is a major branch of a common condensation that provides osteogenic mesenchyme to both maxillary and mandibular arches establishes a closer link between mechanisms controlling development of the skeleton in these two arches than previously suspected. Preosteoblasts (alkaline phosphatase-positive cells) form in the mandible at H.H. early 25, which is before condensation but after the epithelial-mesenchymal interaction upon which preosteoblast formation and condensation depend--neither form in isolated mesenchyme, whereas both form after recombination of mesenchyme and epithelium. Tenascin was present in the mandibular epithelium only at H.H. stage 19 but not in the mesenchyme at any age. Therefore, the epithelial-mesenchymal interaction controls initiation of osteogenesis at the preosteoblast stage. Preosteoblasts then condense, transform into osteoblasts and deposit bone matrix. Differentiation of preosteoblasts precedes condensation which amplifies their number. This is in contrast with chondrogenesis where condensation triggers prechondroblast differentiation.

Mandibular arteriovenous malformation diagnosed by MR and MRA: a case report

A case of mandibular arteriovenous malformation (AVM) is presented. Prompt diagnosis and appropriate management are essential due to massive bleeding or even death after dental extraction or biopsy. Angiography remains the gold standard in detecting the lesion. Magnetic resonance (MR) imaging with spin-echo sequences reveals the vascular malformation as signal-void. MR angiography can demonstrate the nidus, dilated artery and vein. MR imaging and MR angiography can supplement angiography in the diagnosis of mandibular AVM.

Facial intraosseous arteriovenous malformations: CT and MR features

OBJECTIVE

To present the CT and MR findings of two patients with maxillofacial intraosseous arteriovenous malformations (AVMs) before and after endovascular therapy.

MATERIALS AND METHODS

Two young girls suffering from AVMs in the maxilla and mandibula with spontaneous bleeding in the oral cavity were examined by CT and MR on a 1.5 T GE unit before and after selective endovascular embolization.

RESULTS

Computed tomography using a high-resolution algorithm and two-dimensional reconstructions demonstrated the morphology of the bony lesions as well as the regrowth of the bone after successful embolization. Magnetic resonance was the best imaging technique to show vessel structures and the accompanying soft tissue changes. Angiography showed the exact angioarchitecture of the AVM and was essential for therapy planning.

CONCLUSION

Because selective endovascular embolization of maxillofacial AVMs is gaining in importance, CT and MRI are, therefore, essential for diagnosis and therapy planning as well as for follow-up imaging.

[A case of mandibular retromolar canal: elements of nerves and arteries in this canal]

The large bilateral mandibular retromolar canals were found in a 47-year-old Japanese man. This paper presents the nature and distribution of the elements of nerves and arteries in the left retromolar canal which were able to examined. The left mandibular retromolar canal arose from the bifurcation of the mandibular canal at 18 mm anterior to the mandibular foramen and it opened on the surface of the retromolar fossa at 13 mm posterior to the third mandibular molar. The total length of the retromolar canal from the bifurcation to the retromolar foramen was about 16 mm, and 2.5-2.6 mm in diameter. The radiographic image of this retromolar canal was a liner shadow with thin radiopaque anterior and posterior borders cast on a lateral radiography of the left half of the head. Within the retromolar canal, the artery that was branched from the inferior alveolar artery ran through the canal forwards and joined with the branches of the buccal artery and the facial artery, and then gave off the superior and inferior labial arteries. The nerve (R. retromolaris) in the retromolar canal derived from the inferior alveolar nerve trunk and branched off to the following areas: the third mandibular molar, the mucosa of retromolar triangle, the buccal mucosa, and the buccal gingiva of the mandibular premolar and molar region. The retromolar canals and foramina were found in 8 out of 41 Japanese skulls. Clinically, if the arteries in the retromolar canal become injured, complications may arise such as bleeding, and iatrogenic nerve damage may lead to paralysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Post-irradiation changes in the blood vessels of the adult human mandible

Changes in the inferior alveolar artery and periosteal vessels of the post-irradiation mandible have been investigated. The inferior alveolar artery underwent comparatively little change, stenosis being noted in just over half the specimens examined. The number of periosteal arteries and veins increased, the changes being most marked on the body where the effective tissue dose of radiation was highest. The increase in periosteal vessels was independent of stenosis of the inferior alveolar artery.

Assessment of Bone Formation during Osteoneogenesis: A Canine Model

Distraction osteoneogenesis, callotasis, has been demonstrated to be an effective means of lengthening long bones. A variation of Ilizarov's technique produces a transport disk from one cut surface of bone within a defect and advances the disk to the opposite surface to close the defect. This process, previously described by Costantino et al. (Arch Otolaryngol Head Neck Surg 1990; 116:535–45), demonstrated bone formation within the distraction site. The precise mechanism of bone formation has not yet been described for the mandible. Four conditioned beagles were studied, with one control dog maintained in neutral fixation and three dogs distracted at 0.25 mm every 8 hours. A two-cm defect was closed, and dogs were kept in fixation for 1 week after closure, after which they were killed. Three sites were evaluated: (1) the distraction seam, (2) the interface of the cortical and distracted bone, and (3) the cortexes at the closed defect. Each site was bisected, and one half was decalcified for immunohistochemical and hematoxylin and eosin pathologic evaluation. The vascular basement membrane was labeled for laminin and type IV collagen. Both of these substances demonstrate the differentiation of the vascular matrix component predisposing primary bone formation. Labels were intense at the distraction seam where intense angiogenesis occurred. No hyalin cartilage was observed at the distraction site, which indicates that the fixation was stable and that ossification occurred primarily without intermediate callous formation. This model demonstrated that osteoclasts within the canine model produce bone through primary bone formation within an angiogenic matrix rich in basement membrane laminin and type IV collagen. Likewise, bone is species specific in mineral composition for dog mandible. Understanding the formation and composition of distracted bone is essential for understanding application of this technique within the clinical setting.