A rostral neurovascular system in the mosasaur Taniwhasaurus antarcticus.

Mosasaurs were a cosmopolitan group of marine squamate reptiles that lived during the Late Cretaceous period. Tylosaurinae mosasaurs were characterized for having an edentulous rostrum anterior to the premaxillary teeth. External morphology of the snout of the tylosaurine Taniwhasaurus antarcticus from the Upper Cretaceous beds at James Ross Island (Antarctic Peninsula) shows a complex anatomy with diverse large foramina and bone sculpture. A computed tomography scan of the Taniwhasaurus rostrum revealed a complex internal neurovascular system of branched channels in the anteriormost part of the snout. Systems like this are present in extant aquatic vertebrates such as cetaceans and crocodiles to aid them with prey detection, and are inferred to have functioned in a similar manner for several extinct reptile clades such as plesiosaurs and ichthyosaurs. Thus, it is probable that Taniwhasaurus also was able to detect prey with an enhanced neural system located in its rostrum. This condition may be more widespread than previously thought among mosasaurs and other marine reptiles.

Vascularization in Craniofacial Bone Tissue Engineering.

Craniofacial bones, separate from the appendicular skeleton, bear a significant amount of strain and stress generated from mastication-related muscles. Current research on the regeneration of craniofacial bone focuses on the reestablishment of an elaborate vascular network. In this review, current challenges and efforts particularly in advances of scaffold properties and techniques for vascularization remodeling in craniofacial bone tissue engineering will be discussed. A microenvironment of ischemia and hypoxia in the biomaterial core drives propagation and reorganization of endothelial progenitor cells (EPCs) to assemble into a primitive microvascular framework. Co-culture strategies and delivery of vasculogenic molecules enhance EPCs' differentiation and stimulate the host regenerative response to promote vessel sprouting and strength. To optimize structural and vascular integration, well-designed microstructures of scaffolds are biologically considered. Proper porous structures, matrix stiffness, and surface morphology of scaffolds have a profound influence on cell behaviors and thus affect revascularization. In addition, advanced techniques facilitating angiogenesis and vaculogenesis have also been discussed. Oxygen delivery biomaterials, scaffold-free cell sheet techniques, and arteriovenous loop-induced axial vascularization strategies bring us new understanding and powerful strategies to manage revascularization of large craniofacial bone defects. Although promising histological results have been achieved, the efficient perfusion and functionalization of newly formed vessels are still challenging.

Current opinion in otolaryngology: update on vascular injuries in craniomaxillofacial fractures.

PURPOSE OF REVIEW: The primary purpose of this chapter is to define current recommendations for vascular work-up of patients with craniomaxillofacial (CMF) trauma with emphasis on imaging to include intraoperative fluorescence, angiography, and surgical exploration. The second goal is to review current management recommendations for observation versus surgical exploration based on the neck zones of injury. RECENT FINDINGS: Over the past two decades, endovascular techniques are increasingly utilized, particularly in zones I and III of the neck. Additionally, modern advances in radiographic technology have allowed for selective exploration of penetrating zone II injuries. A high suspicion for blunt cerebrovascular injury should be maintained for patients with high-speed deceleration mechanisms of injury, with a majority of patients managed with medical therapy or conservative monitoring over surgical intervention. SUMMARY: CMF fractures are associated with vascular injuries to the intracranial carotid system, extracranial carotid system, or vertebral artery system. A thorough understanding of at risk patients, optimal work-up, and timely treatment algorithms is imperative given the devastating sequellae of stroke and death.

[Prefabrication of vascularized facial bones]. / Präfabrikation vaskularisierter Gesichtsknochen.

Critical size defects in the craniomaxillofacial region often result from ablative tumor surgery, inflammation and posttraumatic deformities. To date, autologous bone grafts are still the gold standard for the reconstruction of these defects; however, they are frequently associated with severe donor site morbidity as well as functional and aesthetic compromises. In this context various resorbable and non-resorbable bone replacement materials have been developed and intensively investigated. Particularly in critical size defects these materials fail due to their lack of osteogenic potential and endogenous vascularization. The combination of alloplastic osteoconductive scaffolds, osteogenic cells, and axial prevascularization in bioartificial bone grafts might present an innovative approach for the microsurgical reconstruction of critical size defects.

Anatomical study of the vascular territories of the maxilla: role of the facial artery in allotransplantation.

BACKGROUND: Facial composite tissue allotransplantation has recently become a surgical option. The maxilla, which forms the upper jaw and plays an important role in facial allotransplantation, consists of the maxillary and facial arteries. The maxillary artery is located deep within the tissue and considered the main artery of the maxilla; however, the facial artery is easy to access. The objective of this study was to examine the territories of the maxillary and facial arteries within the maxilla. MATERIALS AND METHODS: We excised and examined 22 maxillae. Of these, 18 were injected with latex and four with India ink. RESULTS: We observed that the ascending palatine artery, which was collateral with the facial artery, vascularized the maxilla through its dorsal part. The facial artery vascularized the maxilla through its ventral part with the philtral and columellar branches of the superior labial artery. Therefore, the facial artery formed, through the nasal and palatine mucosa, an arterial circle with a dorsal and ventral pole. Angiosomes formed by both the facial and maxillary arteries were also observed. The India ink injected into the facial and maxillary arteries delineated specific territories for each artery. DISCUSSION: This study allowed us to determine the anatomical structures that provide vascularization to the maxilla and describe their different forms. The whole of the maxilla was vascularized by the facial artery, despite the caution imposed by several studies on the removal of the facial artery alone. Indeed, the removal technique was found to be safer when it preserved the anastomoses between the facial and maxillary arteries. Therefore, previous clinical experience and our anatomical study definitively demonstrate that the facial artery vascularizes the maxilla.

Complex rostral neurovascular system in a giant pliosaur.

Pliosaurs were a long-lived, ubiquitous group of Mesozoic marine predators attaining large body sizes (up to 12 m). Despite much being known about their ecology and behaviour, the mechanisms they adopted for prey detection have been poorly investigated and represent a mystery to date. Complex neurovascular systems in many vertebrate rostra have evolved for prey detection. However, information on the occurrence of such systems in fossil taxa is extremely limited because of poor preservation potential. The neurovascular complex from the snout of an exceptionally well-preserved pliosaur from the Kimmeridgian (Late Jurassic, c. 170 Myr ago) of Weymouth Bay (Dorset, UK) is described here for the first time. Using computed tomography (CT) scans, the extensive bifurcating neurovascular channels could be traced through the rostrum to both the teeth and the foramina on the dorsal and lateral surface of the snout. The structures on the surface of the skull and the high concentrations of peripheral rami suggest that this could be a sensory system, perhaps similar to crocodile pressure receptors or shark electroreceptors.

Surgical treatment of vascular malformations of the facial bones.

PURPOSE: To characterize intraosseous vascular malformations and describe the most appropriate approach for treatment according to clinical experience and a review of the published data. MATERIALS AND METHODS: We performed a retrospective review of 11 vascular malformations (7 venous and 4 arteriovenous) of the facial bones treated during a 10-year period using en bloc resection or intraoral aggressive curettage alone or preceded by endovascular embolization. Corrective surgery was planned to address any residual bone deformities. The cases were reviewed at a mean follow-up point of 6 years. RESULTS: Facial symmetry was restored in the cases requiring reconstruction. Tooth sparing was possible in the case of jaw and/or maxillary localization. Recanalization occurred in 14% of the venous and 33% of the arteriovenous malformations. CONCLUSIONS: Facial intraosseous venous malformations can be successfully treated using surgery alone. Facial intraosseous arteriovenous malformations will be better addressed using combined approaches. Aggressive curettage will obviate the need for extensive surgical resection in selected cases.

Vascularization of the facial bones by the facial artery: implications for full face allotransplantation.

BACKGROUND: The maxillary artery is recognized as the main vascular supply of the facial bones; nonetheless, clinical evidence supports a codominant role for the facial artery. This study explores the extent of the facial skeleton within a facial allograft that can be harvested based on the facial artery. METHODS: Twenty-three cadaver heads were used in this study. In 12 heads, the facial, superficial temporal, and maxillary arteries were injected. In one head, facial artery angiography was performed. Ten facial allografts were raised. The soft tissues were dissected to show the arterial anastomotic connections. Radiographs and computed tomographic scans were obtained. RESULTS: Constant anastomosis between the facial, inferior alveolar, and infraorbital arteries at the mental and infraorbital foramina were found. The facial artery vascularized the homolateral mandibular symphysis, body, and ramus. The condylar and coronoid processes were vascularized in 67 percent of the allografts. The homolateral maxilla was contrasted in all allografts. The alveolar and palatine processes contained the contrast in 83 percent of specimens. The maxillary process of the zygomatic bone was perfused in all allografts, followed by the body, frontal (83 percent), and temporal processes (67 percent). The nasal lateral wall and septum were vascularized in 83 percent of the allografts. The medial and lateral orbital walls and the orbital floor were stained in all specimens. The zygomatic process of the temporal bone was the least perfused bone. CONCLUSION: A composite allograft containing 90 to 95 percent of the facial bones can be based on bilateral facial arteries.

Bisphosphonate-related osteonecrosis of jaw (BRONJ): an anti-angiogenic side-effect?

Bisphosphonates are recommended in the treatment of osteoporosis and some cancers, in which case they prevent the appearance of bone metastasis. The patients taking bisphosphonates are at increased risk of developing bisphosphonate-related osteonecrosis of jaw (BRONJ) which is characterised by the presence of an un-healing wound after dental surgery. BRONJ might represent an anti-angiogenic side effect. However, the real number of patients with BRONJ might be higher than currently recorded. Considering the differential diagnosis which includes various primary and secondary cancers, a correct histopathological diagnosis is very important. The morphological criteria for diagnosis of BRONJ are highlighted in this material.

The emergency control of traumatic maxillofacial haemorrhage.

Maxillofacial trauma is common and may lead to haemorrhage that is associated with actual or impending airway compromise. This study briefly discusses the aetiology of midfacial haemorrhage and describes a simple effective technique of midface splintage for haemorrhage control, which may be applied in the prehospital and emergency environments. This technique has been used successfully by the London Helicopter Emergency Medical Service.

Laser-Doppler examination of the blood supply in pericranial flaps.

PURPOSE: The purpose of this investigation was to determine if there is evidence suggestive of blood flow within pericranial flaps. PATIENTS AND METHODS: An index of blood flow using laser-Doppler blood flowmetry was obtained in pericranial flaps from 10 patients who were undergoing a coronal flap for reconstructive procedures. The data were analyzed using fast Fourier transformation to indicate the presence or absence of blood flow. RESULTS: All but 1 pericranial flap showed evidence of blood flow within. Most flaps had blood flow even several centimeters distal to the origin of the flaps' pedicles. CONCLUSION: The data clearly indicate that pericranial flaps contain at least some blood flow. However, the quantity of blood flow could not be assessed using this technology.

[Evaluation of the usefulness of vascularized bone grafts for surgical reconstruction of the face]. / Ocena przydatnosci unaczynionych przeszczepów kostnych w rekonstrukcji chirurgicznej twarzy.

The process of healing of vascularised bone grafts was examined clinically and the use of vascularised bone grafts in face reconstruction surgery was assessed basing on author's experience with the surgical technique, availability of graft recipient and donor sites and final outcome. Patients enrolled in this study were treated at the Department of Maxillofacial Surgery, Pomeranian Academy of Medicine in Szczecin, for cancer, injuries, developmental anomalies and atrophic changes. In each case it was necessary to restore facial bone structures of functional and aesthetic importance, including: floor of the orbital cavity, alveolar process of maxilla, palate, malar bone and mandible (Tab. 2). Reconstruction was done mostly with parietal bone grafts pedicled on temporal fascia and muscle, coronoid process of the mandible pedicled on temporal muscle, and lower part of the diaphysis of mandible pedicled on masseter and pterygoid muscles. In some cases, reconstruction material consisted of a rib on greater pectoral muscle, clavicle on sternocleidomastoid muscle and scapular bone crest pedicled on trapezius muscle. Free microvascular flaps with some elements of fibula and radius were used in two patients for the reconstruction of mandible and soft tissues. In total, 41 vascularised grafts were performed in 40 patients. Graft healing was examined clinically and usefulness of this technique for face reconstruction surgery was assessed basing on author's experience with the preparation technique, intraoperative complications and extent of trauma to donor sites. The results of healing of specific grafts are enclosed in Table 1. The surgical technique for graft preparation and its transfer into the recipient site varied from case to case. The most difficult and effortful approach was with free bone grafts transferred from remote sites by means of a microsurgical technique (group V). Despite the complexity of the reconstruction method, no intraoperative complications occurred in the course of preparation of the radial and fibular bone grafts. In group IV, the most difficult grafts included those taken from ribs, clavicle and scapular bone. Parietal bone grafts were much less troublesome (subgroups Ia and Ib) although associated with the largest number of intraoperative complications. The easiest preparation method applied to the grafting of coronoid process and lower part of the body of mandible (group II and III). Clinical evaluation of vascularised bone grafts confirmed without reservations the value of this approach in face reconstruction surgery. However, the extent to which individual graft types proved to be usable varied. The most valuable ones included parietal bone grafts pedicled on temporal muscle and fascia used for restoring upper and central facial structures and the coronoid process of mandible pedicled on temporal muscle used for reconstructing the floor of the orbital cavity and alveolar process of the maxilla. Rib grafts pedicled on pectoral muscle were of limited use. The same applies to grafts from the lower part of the body of mandible pedicled on masseter and pterygoid muscles occasionally used for restoring the mental part of mandible. Grafts from remote sites (fibula, radius) should be used only when other reconstruction methods are unavailable.

Facial translocation approach to the skull base: the viability of translocated facial bone graft.

OBJECTIVES: A retrospective review of 56 patients who were operated through a facial translocation approach was carried out to assess the viability of the translocated facial bone segment. METHODS: Eleven patients had preoperative radiotherapy, and 26 had postoperative radiotherapy. In 14 patients the translocated bone segment was kept attached to the anterior cheek, and in 42 patients the bone segment was detached and then implanted. A vascularized flap was used to obliterate the defect in the paranasal sinuses in 15 patients. RESULTS: Twelve (21.4%) patients had devitalized bone segment and required sequestrectomy. The incidence of devitalized bone segment was higher in the patients who received postoperative radiotherapy (P = 0.04) and lower in the patients in whom the defect in the paranasal sinuses was reconstructed with a vascularized flap (P = 0.006). CONCLUSIONS: The translocated facial bone segment should be kept attached to the cheek soft tissue when possible, or the defect in the paranasal sinuses should be reconstructed with a vascularized flap.

Late gestational vascular disruptions inducing craniofacial anomalies: a fetal lamb model.

We report our preliminary observations in six fetal lambs that were surgically manipulated in utero to impede the blood flow of the carotid arteries and their branches, including the laryngeal artery, the anastomotic branch between the vertebral artery and the occipital artery, the auricularis and the transverse facial arteries. Between 115 and 117 days of gestation (term pregnancy 147 days), all ewes were placed under general anesthesia and mechanical ventilation. Their fetuses were exteriorized and catheters were placed in their femoral artery for blood gas sampling. A balloon occluder and a blood flow probe were placed on one internal carotid while the contralateral side was completely ligated. On the third day post surgery, the balloon occluder was inflated three times for 30 minutes each time at 30 minute intervals in the experimental fetuses. PO2, PCO2, pH, lactate and glucose were monitored during the study. At 7 days post occlusion, all animals were sacrificed and tissues were collected. Craniofacial anomalies were obvious in three animals similar to those seen in hemifacial microsomia, Goldenhar syndrome and Pierre-Robin sequence. All three control animals had normal craniofacial structures. This preliminary data suggests that late gestation vascular disruptions may lead to significant craniofacial anomalies, as seen in our animal model.

Morphological study of the human maxillofacial venous vasculature: examination of venous valves using the corrosion resin cast technique.

BACKGROUND: The venous drainage in the human head and neck, structures located superior to the heart, generally does not counter the force of gravity. Accordingly, venous valves in the human head have been reported to be few or nonexistent, and therefore the direction of venous drainage is variable and obscure. METHODS: We investigated whether venous valves were present in 13 heads of human adult cadavers using scanning electron microscopic observation of corrosive resin casts in the human maxillofacial region. This technique afforded the observation of the venous valves. RESULTS: Venous valves were found throughout the facial region. In particular, there were many valves distributed in the lingual, upper and lower labial, facial and pharyngeal veins. The venous valves were particularly well formed at motile parts of the maxillofacial region. CONCLUSIONS: It is suggested that these valves may aid the venous blood return and permit the blood drainage in one direction.

Effects of prostaglandins on the skeleton.

Prostaglandins (PGs), particularly those of the E series, have potent effects on bone resorption in vitro and on bone formation, bone remodeling, and bone modeling in vivo. When given systemically, PGEs have powerful anabolic effects--increasing bone formation rates, bone modeling in the formation mode, and remodeling with a net increase in bone mass. When applied locally, PGE1 increases periosteal bone formation and alveolar bone mass, and appears to promote periodontal soft-tissue regeneration. PGs have potential clinical application in the local restoration or augmentation of bone mass, focal stimulation or bone formation, and the regeneration of soft tissues associated with osseous tissues, such as fibrous and ligamentous insertions into bone.

HMPAO scintigraphy, MRI, and CT of a vascular fibrous dysplasia of the craniofacial bones.

The authors present the case of a child with a predominantly unilateral craniofacial fibrous dysplasia and a substantial redirection of internal carotid blood flow to the dysplastic bone. The case illustrates the advantages of using multiple imaging modalities in the evaluation of this disorder. CT showed the diagnostic findings of fibrous dysplasia and demonstrated the extent of bony involvement. MRI showed the extent and vascularity of the intradiploic fibrous mass and best demonstrated the distortion of underlying cerebral structures. Tc-99m HM-PAO brain scintigraphy demonstrated adequate ipsilateral cerebral perfusion, thereby excluding any significant cerebral "steal."