CD9 Expression on Lymphatic Vessels in Head and Neck Mucosa

CD9, a member of the transmembrane 4 superfamily, is involved in cell adhesion, migration, and tumor metastasis. Little is known about its vascular expression pattern. In this study, we investigated CD9 expression on endothelial cells in the mucosa of the head and neck and compared it with vascular tumors. Using immunohistochemistry, expression of CD9 was studied in 17 samples of head and neck mucosa and skin (laryngeal mucosa: n = 2, oral: n = 6, and epidermis: n = 9) and a variety of vascular tumors (lymphangiomas: n = 9, juvenile nasopharyngeal angiofibromas: n = 4, hemangiomas: n = 7, angiosarcomas: n = 5, and Kaposi's sarcomas: n = 7) and compared with the expression of CD34 and PAL-E (blood vessel markers) and the lymphatic marker podoplanin. Regular lymphatic endothelium and lymphangiomas were strongly positive for CD9 and podoplanin but were mostly negative for PAL-E and CD34. By contrast, blood vessel endothelium and hemangiomas were strongly positive for PAL-E and CD34 but were mostly negative for CD9 and podoplanin. Weak to moderate CD9 reactivity was also observed on EC of juvenile nasopharyngeal angiofibromas, angiosarcomas, and Kaposi's sarcomas. Expression of CD9 by lymphatic EC was confirmed by reverse-transcriptase PCR and Western blot analyses. CD9 may be useful as a marker for lymphatic EC. It could promote the adherence of inflammatory and tumor cells to lymphatic EC and participate in the growth and maintenance of the lymphatic capillary net.

Head and neck vascular malformations: time-resolved MR projection angiography

Extracranial vascular anomalies can be divided into haemangiomas and vascular malformations. The latter can be subdivided on the basis of the predominant type of vascular channels. Separation of high- and low-flow vascular malformations is of clinical importance. We report preliminary observations on time-resolved magnetic resonance projection angiography (MRPA) of vascular malformations of the head and neck. We examined eight patients with vascular anomalies of the head and neck. On MRPA the time between the early arterial phase and enhancement of the malformation could be used to distinguish high- and low-flow lesions. High-flow arteriovenous malformations showed early, intense enhancement. Venous malformations were either not visible on MRPA or showed late enhancement of veins. One patient was examined after embolisation of an arteriovenous fistula of the mandible. Normal MRPA was taken to indicate absence of a residual lesion.

Early experience with computed tomographic angiography in microsurgical reconstruction

Preoperative angiography is frequently used in the planning of microsurgical reconstruction. However, several potentially devastating complications can result from angiography, including arterial occlusion and pseudoaneurysm. Computed tomographic angiography is a relatively new technique that can provide detailed information about vascular anatomy as well as soft and bony tissue without the risks of traditional angiography. In addition, three-dimensional image reconstruction uniquely demonstrates anatomical relationships among blood vessels, bones, and soft tissue. Fourteen computed tomographic angiograms were obtained in 10 patients undergoing microsurgical reconstruction of the head and neck, lower extremity, or upper extremity. The average patient age was 46.9 years (range, 22 to 67 years). Charges related to the computed tomographic procedure were compared with those of conventional preoperative imaging for microsurgical repair. At our institution, the average computed tomographic angiogram charge was 1140 US dollars, whereas the average charge for traditional arteriography was 3900 US dollars. When compared with intraoperative evaluation, computed tomographic angiograms demonstrated clinically relevant surgical anatomy. No complications were noted for the radiographic procedure or after free flap reconstruction. Computed tomographic angiography provides high-resolution, three-dimensional arterial, venous, and soft-tissue imaging without the risks of traditional angiogram and at a lower cost.

Morphogenesis of blood vessels in the head muscles of avian embryo: spatial, temporal, and VEGF expression analyses

Adult skeletal muscle is a highly vascularized tissue, but the development of intramuscular endothelial networks has not been well studied. In quail embryos, QH1-positive angioblasts are present and moving throughout myogenic head mesoderm before the onset of primary myotube formation. On day 5 of incubation, concurrent with early myotube formation and aggregation, angioblasts establish a transient vascular plexus surrounding the myogenic condensations. Between days 5 and 9, the intramuscular vessels form an irregular network of endothelial cords and patent channels and only later are the parallel arrays of capillaries characteristic of adult muscles established. Microinjections using India ink, QH1, and Mercox resin reveal that these intramuscular capillaries are typically not connected to systemic vessels of the head until day 10, which is near the end of primary myogenesis and corresponds to the onset of muscular function. Morphometric analyses performed during primary myogenesis stages show a decrease in muscle cell density but no significant changes in intramuscular vascular density between days 5 and 9. This finding was surprising, as it is generally assumed that muscle growth requires elevated oxygen and nutrient levels. Moreover, there are no significant morphometric differences in vascular supply to embryonic fast and slow muscles. Endothelial tissue density is similar in slow muscles (oculorotatory, e.g., lateral rectus), fast muscles (mandibular depressor), and mixed muscles, in which the fiber types can be interspersed (jaw adductors) or segregated (branchiomandibular). Vascular endothelial growth factor (VEGF) protein is abundant in myotubes but not endothelial cells within both fast and slow head muscles at days 7 and 9. However, in some mixed muscles, only a minority of myotubes, which do not correspond to one specific fiber type, express VEGF. These results document a dynamic set of intramuscular and perimuscular angiogenic reorganizations during avian head myogenesis. Thus far, no vasculogenic distinctions between fast and slow muscles have been observed, although muscle heterogeneity in VEGF expression is evident.

Head & neck vascular and cystic lesions of infancy and early childhood: challenges in diagnosis and management--update

A variety of vascular and cystic lesions exist in the head and neck area of infants and little children. The mode of evaluating these entities is evolving and new treatment modalities are added now and then. An updated knowledge of these lesions and their management is crucial to provide the best care for these patients.

Endovascular Therapy of Traumatic Vascular Lesions of the Head and Neck

Pseudoaneurysm and fistula formation are well-documented complications of arterial vascular injury and may be associated with significant morbidity and mortality. The purpose of this manuscript is to review the presentation and therapy of patients with traumatic vascular injuries of the head and neck. Eight patients were admitted to a Level 1 Trauma Center and diagnostic angiography of the carotid artery and vertebral circulation was performed. The mechanisms of injury included motor vehicle accident, gunshot wound, stab wound and aggravated assault. Cause of trauma, vascular lesion, endovascular therapy and outcome were analyzed retrospectively. The angiographic findings, clinical presentation and hospital course were reviewed. There were eight patients, seven males and one female, aged 17-65. Four patients (50%) had multiple lesions; four had pseudoaneurysms, two with fistula formation and two with active arterial hemorrhage. A total of 17 lesions were embolized using coils. Polyvinyl Alcohol (PVA), Gelfoam or a combination. Two of the 17 lesions received stents. Six of the eight patients remained clinically improved or stable at varying follow-up intervals. One of the four patients who presented with penetrating trauma and neurological deficits had resolution of right hemiplegia at the 8th month follow-up. One of the four patients who sustained blunt trauma and carotid-cavernous fistula presented with a new pseudoaneurysm at the 2-month post-embolization follow-up. The evolution of diagnostic neuroangiographic techniques provides opportunities for endovascular therapy of traumatic vascular lesions of the head and neck that are minimally invasive, attractive options in selected cases.

Effect of head elevation on cerebral blood flow velocity in post-cerebral operation patients

This pre-experimental research measured patients' mean blood velocity (MV), peak systolic velocity (PSV), and end-diastolic velocity (EDV) of the middle cerebral arteries by using transcranial Doppler (TCD) to understand the immediate changes in cerebral blood flow (CBF) when head elevation degree changed, and whether CBF will return to stability after 10 minutes of elevation. Ten patients who underwent cerebral surgery were selected from one medical centre by purposeful sampling within five months. One-way ANOVA was used to analyze the data. The study results showed that MV, PSV, and EDV had obviously changed when head elevation was 15 degrees, 30 degrees, or 45 degrees from the horizontal at 10 seconds, and then recovered gradually. This study examined four head elevation degrees that affected cerebral blood flow. The results are likely to help nurses in caring for these patients.

Infant seizures not so infantile: first-time seizures in children under six months of age presenting to the ED

Data regarding first-time seizures in children <or=6 months of age is limited. This retrospective study, therefore, reviews the presentation, management, and outcome of children <or=6 months of age presenting to a pediatric tertiary care facility with a first-time seizure. Charts for 31 patients were identified and reviewed. Nineteen patients (61%) received sepsis work-ups. Two of the 31 (7%) had infectious etiologies. One of these infants, a 3-month-old who presented with only a history of fever and eyes rolling back but otherwise appeared well on initial presentation, had pneumococcal meningitis. Neuroimaging studies were performed in 22 (71%) patients with 12 of 22 (54%) having abnormal findings. Electroencephalogram (EEGs) were performed on 22 patients (71%) with 11 (50%) showing seizure activity. Electrolytes were checked on 19 patients (61%) with 5 being clinically significant. Etiologies included idiopathic (32%), congenital anomalies (26%), inborn errors of metabolism (16%), electrolyte abnormalities (16%), infection (7%), and trauma (3%). In conclusion, unlike children >6 months of age in whom febrile seizures and idiopathic seizure disorders are most common, a large percentage of children <or=6 months of age presenting with first-time seizures have significant underlying pathology. This pathology often includes immediately life-threatening conditions in these children who may look deceptively well on initial evaluation.

[Indications for primary surgical therapy of vascular abnormalities in infancy]

LASER THERAPY: Since the introduction of laser therapy for treatment of hemangiomas and vascular malformations, primary surgical therapy has gradually lost importance. Particularly hemangiomas, but also venous malformations and lymphangiomas, are nowadays primarily treated by different types of lasers. Especially the Nd:YAG laser with a percutaneous or transcutaneous application technique often leads to satisfying results.

SURGICAL THERAPY

Surgical therapy is mostly used secondarily in late childhood or in adults after several laser applications for excision of residual scars or other corrective procedures. Despite these improvements in laser therapy, there is still an indication for primary surgical treatment in subcutaneous vascular malformations and in rapidly growing hemangiomas after unsuccessful laser therapy. Even in large vascular anomalies, safe excision with only a little blood loss is possible if the tumors are encapsulated.

CASE REPORTS

In this paper we want to point out the necessity of primary surgery in three children in whom complications such as loss of sight, facial nerve palsy, and a lethal outcome due to massive hemorrhage in a cystic lymphangioma could be avoided.

Rapid technique for imaging the blood vascular system using stereoangiography

Data on vascular anatomy traditionally have been derived from time-consuming gross dissection and histology, which has prevented the assembly of large sample sizes. Vascular injection of radiopaque medium (angiography) is a rapid technique, but, as typically performed, it has limitations (e.g., superimposition and poor subsequent dissectibility). We present a novel angiographic technique comprised of two elements: 1) a new, dissectible injection medium; and (2) stereoradiography. The injection medium consists of liquid barium (providing radiopacity) and latex (providing dissectibility). Domestic duck heads were the study system. The relative concentrations of barium and latex were varied, and the resulting radiographs were assayed for vessel radiopacity and the number of observable vessels. A wide range of barium percentages yielded excellent results, suggesting that preparation of the medium can be "eyeballed" for most applications, which enhances processing speed. The stereoradiographic element solved the superimposition problem, allowing stunning resolution of the spatial relationships of vessels to each other and to other tissues. Stereoangiography is a fast and easy technique that permits the acquisition of detailed anatomical data from many specimens, thereby enabling something rarely achieved: population-level anatomical studies.

Leech therapy for patients with surgically unsalvageable venous obstruction after revascularized free tissue transfer

OBJECTIVE

To assess the efficacy and associated complications of a leech therapy protocol used for patients with a head and neck free tissue transfer in whom flap viability is threatened because of surgically unsalvageable venous obstruction.

DESIGN

Medical record review of a prospective protocol.

SETTING

Tertiary care academic medical center.

PATIENTS

Of the 450 free tissue transfers to the head and neck region performed by our microvascular program from January 1, 1995, to October 31, 2000, 8 patients (1.8%) developed venous obstruction not considered salvageable by conventional surgical or thrombolytic therapy.

INTERVENTIONS

All 8 patients were placed on a protocol using leeches (Hirudo medicinalis), intensive care unit monitoring, antithrombotic pharmacotherapy, frequent hematologic evaluation, blood transfusions as needed, and antibiotic prophylaxis for Aeromonas hydrophila.

MAIN OUTCOME MEASURES

Flap salvage rate, number of leeches used per patient, time needed for inosculation, duration of intensive care unit admission, transfusion requirement per patient, and complications during leech therapy.

RESULTS

All 8 flaps survived with the application of this protocol. An average of 215 leeches were used per patient, and the average time needed for inosculation was 6.6 days. The average duration in the intensive care unit was 9.6 days. The morbidity of our protocol was substantial, with intensive care unit psychosis, prerenal azotemia, and large transfusion requirements being the most frequent complications. An average of 13 U of packed red blood cells per patient was necessary.

CONCLUSIONS

Aggressive application of the presented leech therapy protocol can salvage free tissue transfers with venous obstruction that are otherwise unsalvageable. The associated morbidity can be marked. Thus, judicious application of this protocol for flap preservation is essential.

Disruption ofacvrl1increases endothelial cell number in zebrafish cranial vessels

The zebrafish mutant violet beauregarde (vbg) can be identified at two days post-fertilization by an abnormal circulation pattern in which most blood cells flow through a limited number of dilated cranial vessels and fail to perfuse the trunk and tail. This phenotype cannot be explained by caudal vessel abnormalities or by a defect in cranial vessel patterning, but instead stems from an increase in endothelial cell number in specific cranial vessels. We show that vbg encodes activin receptor-like kinase 1 (Acvrl1; also known as Alk1), a TGFβ type I receptor that is expressed predominantly in the endothelium of the vessels that become dilated in vbg mutants. Thus, vbg provides a model for the human autosomal dominant disorder, hereditary hemorrhagic telangiectasia type 2, in which disruption of ACVRL1 causes vessel malformations that may result in hemorrhage or stroke.

Movies available on-line

Quantitative evaluation of the relative contribution ratio of cerebral tissue to near-infrared signals in the adult human head: a preliminary study

Combining spatially- and time-resolved spectroscopies. we attempted to quantitatively evaluate the contribution ratio of the partial mean pathlength of cerebral tissue to the observed overall mean pathlength, in which haemoglobin concentrations were selectively changed by administration of acetazolamide. When acetazolamide was administered, the observed increases in oxygenated haemoglobin depended on the probe distance, which became progressively larger at distances of 2, 3 and 4 cm. Increases in oxygen saturation were detected at 3 and 4 cm spacing, but not at 2 cm. Assuming that the modified Lambert-Beer's law can exist in the inhomogeneous structure of the head, then, we could estimate the contribution ratio of the cerebral tissue to optical signals at the probe distances of 2, 3 and 4 cm as 33%, 55% and 69%, respectively. Using these values, we recalculated acetazolamide-induced concentration changes in oxygenated-haemoglobin in the cerebral tissue, which resulted in the same values at distances of 2, 3 and 4 cm as expected. Thus, our present method opened the door to the possibility of selectively obtaining optical signals attributed to cerebral tissue.

Transient orthostatic hypotension is common in adolescents

OBJECTIVES

We hypothesized that transient hypotension associated with the symptom of lightheadedness with standing is a common phenomenon in healthy adolescents but may be mistaken for orthostatic intolerance.

STUDY DESIGN

We studied 23 healthy adolescents, combining upright tilt to 70 degrees and to 35 degrees (in 12 patients) with continuous heart rate and blood pressure (BP) measurements. We measured peripheral blood flow and venous pressure in the arms and legs by using venous plethysmography.

RESULTS

Healthy subjects with normal vasoconstrictive responses to sustained upright tilt uniformly have a transient fall in BP during 70 degrees upright tilt that varies from almost undetectable to large decreases in BP easily exceeding the 20-mm Hg threshold for orthostatic hypotension. Large decreases are associated with short-lived symptoms of lightheadedness and are most marked in those with the largest calf blood flow. The higher the flow, the lower the BP falls. There is appropriate reflex tachycardia.

CONCLUSIONS

We conclude that transient orthostatic hypotension is common in many healthy adolescents, especially after prolonged recumbency, and is related to dependent vascular tone.

Neuroectodermal origin of brain pericytes and vascular smooth muscle cells

The origin of vascular pericytes (PCs) and smooth muscle cells (vSMCs) in the brain has hitherto remained an open question. In the present study, we used the quail-chick chimerization technique to elucidate the lineage of cranial PCs/vSMCs. We transplanted complete halves of brain anlagen, or dorsal (presumptive neural crest [NC]) or ventral cranial neural tube. Additional experiments included transplantations of neuroectoderm into limb mesenchyme, and of head mesoderm or limb mesenchyme into paraxial head mesoderm. After interspecific transplantation of quail brain rudiment, graft-derived vSMCs were found in the vessel walls of the grafted brain. Notably, transplanted ventral neural tube also gave rise to vSMCs. After grafting of quail head mesoderm, quail endothelial cells were found in the host brain, but no vSMCs of donor origin. Grafting of quail whole or ventral neural tube into the limb bud led to endowment of graft and host vessels with graft-derived vSMCs. Quail limb bud mesenchyme contributed to vSMCs in the ectopic neural graft, but, when transplanted into paraxial head mesenchyme, it did not form intraneural vSMCs. After orthotopic transplantation of cranial NC, graft-derived vSMCs were not only found in meninges and brain of the operated side, but also on the contralateral side. Our results show that 1) avian cranial neuroectoderm is able to differentiate into vSMCs of the brain; 2) this potential is not restricted to the prospective NC; and 3) neither cranial mesoderm nor cranially transplanted limb bud mesoderm can give rise to brain vSMC.

Thymus size and head circumference at birth and the development of allergic diseases

BACKGROUND

The positive association between a large head circumference at birth and total serum IgE levels has been suggested to be due to negative associations between head circumference at birth and thymus development and between thymus development and total serum IgE levels.

OBJECTIVES

To examine the associations between head circumference and thymus size at birth and the development of allergic disease.

METHODS

The size of the thymus was assessed by sonography during the first week of life in 149 healthy term infants. Information on birth characteristics and mode of delivery was collected at delivery. The presence of allergic disease was assessed 5 years later by mailed questionnaires, which were returned by 85% of the eligible families.

RESULTS

At birth, head circumference was positively associated with thymus size (P < 0.001). In all, 27 (23%) of the children had developed at least one allergic disease. Multivariate analysis revealed that both parental allergy (Prevalence Ratio and 95% CI) = 3.18 (1.49-6.78)) and caesarean delivery (2.62 (1.48-4.64)) were independently correlated with allergic disease, whereas thymus size was not.

CONCLUSIONS

Our study does not support that a large head circumference is associated with a small thymus size, nor that a small thymus size is associated with allergic disease. Whether thymus size at birth is related to total serum IgE levels still remains to be elucidated.

Current concepts in the classification, diagnosis and treatment of hemangiomas and vascular malformations of the head and neck

There are many different classifications of vascular anomalies. As the correct classification of the vascular lesion has a direct influence on therapy it is difficult to decide which treatment should be considered as the treatment of choice. Based on an extensive review of the literature and personal experience of the treatment of more than 200 patients with hemangiomas or vascular malformations of the head and neck, a clinical classification is described that allows vascular lesions to be categorized in order to plan purposeful treatment. In general, hemangiomas represent the main group of vascular lesions in infancy and childhood. They are usually apparent a few weeks after birth and are characterized by an initially rapid growth of epithelial cells, followed by spontaneous involution. Hemangiomas should be differentiated from vascular malformations that are present at birth but may not be evident clinically. Spontaneous involution of vascular malformations has never been reported, whereas laser therapy can induce involution of hemangiomas at an early stage in a majority of cases. In certain situations steroids or surgical removal may seem to be the appropriate therapy of choice. In contrast, vascular malformations have to be treated according to their histopathology and location, as well as their hemodynamic features as shown radiographically with angiography. The accurate diagnosis of vascular anomalies is essential for further treatment, as shown by clinical experience at the University of Marburg.

The angiosome concept applied to arteriovenous malformations of the head and neck

Arteriovenous malformations remain a difficult clinical problem. There is very little understanding of the underlying pathogenesis of these lesions, and therapy frequently involves considerable risks with suboptimal outcomes. Recently, a comprehensive description of the angiosomes of the head and neck was completed in the authors' unit. It was noticed that the location of several clinically observed arteriovenous malformations in the head and neck seemed to correspond to the anatomic location of the choke anastomotic zones linking the angiosomes. Therefore, selective clinical angiograms were compared with those from the authors' previously performed fresh cadaver injection studies, in which they defined the angiosomes of the head and neck. In each patient, the location of the arteriovenous malformation corresponded directly to the choke vessel anastomotic zone linking two or more adjacent angiosomes. Clinical and pathologic ramifications of this observation are discussed.

Vascular anomalies of the head and neck

Vascular abnormalities of the head and neck are relatively uncommon lesions. An understanding of these anomalies based on their pathogenesis and natural history clearly divides them into hemangiomas and vascular malformations. Treatment strategies that are reasonable and predictable can then be devised based on the aforementioned factors.

[Perthes syndrome. The classical symptom triad as a rarity in trauma surgery practice]

Perthes syndrome or traumatic asphyxia is a condition characterised by subconjunctival hemorrhage, cervicofacial petechiae and cyanosis caused by severe compression of the chest. Diagnosis is made by history and clinical examination. Associated injuries such as intrathoracic or abdominal lesions can be life-threatening and must be strictly assessed. This report demonstrates an illustrative case of this rare injury.

[Diagnostic values of MRI in combination with DSA in vascular malformations of the head and neck]

OBJECTIVE

To evaluate prospectively diagnostic values of magnetic resonance imaging (MRI) as the initial examination for vascular malformations of the head and neck, and establish a flowchart based on radiodiagnostic features.

METHODS

45 patients with vascular malformations of the head and neck were evaluated prospectively with MRI. MRI was followed by angiography in 15 patients, contrast-enhanced CT in 15 patients. MRI was performed by using spin-echo pulse sequences with Philips Gyroscan NT 1.0 Teslaunit.

RESULTS

In all cases, MRI demonstrated usefully, and there was no other single imaging modality that could provide information about internal structures and flow characteristics as much as MRI. It made differentiation between high-flow and low-flow lesions obvious, however MRI was inferior to angiography in delineation of feeder vessels.

CONCLUSION

MRI can be used as the initial methods for diagnosis of vascular malformations in the head and neck, and could be combined with angiography in cases with high-flow or combined-flow lesions.

Ischemia/reperfusion injury in microvascular surgery

Ischemia/reperfusion injury is often the final and irreversible factor causing flap failure in microvascular surgery for head and neck defects. This paper begins with a detailed review of flap physiology and ischemia/reperfusion injury at the cellular level. Subsequently, the pharmacotherapeutic agents used clinically and experimentally to avoid or reverse ischemia/reperfusion injury are discussed. The goal of this review is to provide a framework for understanding the expanding body of literature relevant to ischemia/reperfusion injury in microvascular surgery.

Endovascular treatment of acute and subacute hemorrhage in the head and neck

OBJECTIVE

Acute and subacute hemorrhage in the head and neck often represent a life-threatening situation. The goal of this study is to evaluate the indications for and contributions of endovascular techniques in the diagnosis and management of such severe cases.

DESIGN

Seventy-two patients with acute or subacute intractable hemorrhage of the head and neck were treated over a period of 5 years: 2 patients had experienced trauma; in 6 cases the cause of bleeding was iatrogenic; and in 2 patients intraosseous arteriovenous malformations were manifested. Fifteen patients had tumors, 9 of whom had prior radiotherapy. Forty-seven patients presented with epistaxis (41 idiopathic and 6 during anticoagulation therapy). The endovascular therapy was performed using polyvinyl alcohol particles, fibered platinum or electrolytically detachable coils (Guglielmi detachable coils; Target Therapeutics, Fremont, Calif), a stent, glue (Ethibloc; Ethicon GmbH, Norderstedt, Germany, and Histoacryl; B. Braun Melsungen AG, Melsungen, Germany), or with a combination of these different embolic materials.

RESULTS

The acute bleeding was successfully controlled in all cases. Fourteen patients (7 with epistaxis, 5 with tumors, and 2 with arteriovenous malformations) had to be embolized more than once before the bleeding could be controlled. The idiopathic, traumatic, iatrogenic, and remaining tumoral cases were treated only once. The long-term morbidity was 1.9%.

CONCLUSIONS

Owing to the recent continuous advances in interventional radiologic techniques, it is possible to treat both acute and subacute life-threatening head and neck hemorrhage most efficiently. In many cases the endovascular therapy complements surgery.

The angiosomes of the head and neck: anatomic study and clinical applications

The angiosome concept was introduced over a decade ago by Taylor and Palmer, whereby the body was considered to be composed anatomically of multiple three-dimensional composite blocks of tissue supplied by particular source arteries. Since then, detailed studies of the forearm and leg have been examined by Taylor and his coworkers. This study focuses on another region--the head and neck. Six fresh head and neck cadaver specimens were examined after infusion with a radio-opaque lead oxide mixture and correlated with over 24 previous body studies. The vascular anatomy of the skin, superficial musculoaponeurotic system (SMAS), muscles, brain, dura, and bone was examined. Each layer was painstakingly removed, photographed, labeled, and mapped to the respective arteries and veins. A radiologic subtraction technique was used to allow successive layers to be compared. This information was then scanned into a computer, analyzed, color coded, and labeled, thereby producing a three-dimensional study of the head and neck region to identify the respective angiosomes. As in previous detailed examinations of the leg and forearm, the angiosomes were found to be connected usually within tissues, such as muscle, skin, specialized organs or glands, rather than between the tissues. The muscles usually had vessels of two or more angiosomes supplying them and fell into three major groups based on the similarity of their arterial supply. In some areas, the midline anastomoses were rich, especially in the integument of the scalp, forehead, and lips. In other regions, the midline vascular connections were poor, especially in the tongue and palate. No fewer than 13 angiosomes of the head and neck, supplied by the branches of the external carotid, internal carotid, and subclavian arteries, have been defined, mapping their three-dimensional territories in the skin, the deep soft tissues, and the bones. Although most angiosomes spanned between skin and bone, three territories, those of the vertebral, lingual, and ascending pharyngeal vessels, were confined to the deep tissues without cutaneous representation. Finally, this study provides additional data for the surgeon to help plan safer incisions and better reconstructive flap procedures. It also gives information that may help explain the etiology and treatment of head and neck arteriovenous vascular malformations.

[Effective dose and dose to the crystalline lens during angiographic procedures]

Interventional radiology presents the highest dose levels for the staff and for the patient. For a total of 34 angiographic examinations the doses at the forehead and at the neck of a radiologist have been measured. The effective dose and the dose to the eye lens have been estimated over a period of one year. Doses to the lens of the eye close to the limit of 150 mSv proposed by the ICRP have been observed. There is an imminent need for the radiologist to wear also lead glasses to avoid formation of cataracts at long term.

Calibration of near-infrared frequency-domain tissue spectroscopy for absolute absorption coefficient quantitation in neonatal head-simulating phantoms

Frequency-domain tissue spectroscopy is a method to measure the absolute absorption coefficient of bulk tissues, assuming that a representative model can be found to recover the optical properties from measurements. While reliable methods exist to calculate absorption coefficients from source-detector measurements less than a few centimeters apart along a flat tissue volume, it is less obvious what methods can be used for transmittance through the larger tissue volumes typically associated with neonatal cerebral monitoring. In this study we compare the use of multiple distance frequency-domain measurements processed with (i) a modified Beer-Lambert law method, (ii) an analytic infinite-medium diffusion theory expression, and (iii) a numerical finite element solution of the diffusion equation, with the goal of recovering the absolute absorption coefficient of the medium. Based upon our observations, the modified Beer-Lambert method provides accurate absolute changes in the absorption coefficient, while analytic infinite-medium diffusion theory solutions or finite element-based numerical solutions can be used to calculate the absolute absorption coefficient, assuming that the data can be measured at multiple source-detector distances. We recommend that the infinite-medium multi-distance method or the finite element method be used across large tissue regions for calculation of the absolute absorption coefficient using frequency-domain near-infrared measurements at multiple positions along the head.

Photon migration through fetal head in utero using continuous wave, near-infrared spectroscopy: development and evaluation of experimental and numerical models

In this work experimental tissue phantoms and numerical models were developed to estimate photon migration through the fetal head in utero. The tissue phantoms incorporate a fetal head within an amniotic fluid sac surrounded by a maternal tissue layer. A continuous wave, dual-wavelength (lambda = 760 and 850 nm) spectrometer was employed to make near-infrared measurements on the tissue phantoms for various source-detector separations, fetal-head positions, and fetal-head optical properties. In addition, numerical simulations of photon propagation were performed with finite-difference algorithms that provide solutions to the equation of radiative transfer as well as the diffusion equation. The simulations were compared with measurements on tissue phantoms to determine the best numerical model to describe photon migration through the fetal head in utero. Evaluation of the results indicates that tissue phantoms in which the contact between fetal head and uterine wall is uniform best simulates the fetal head in utero for near-term pregnancies. Furthermore, we found that maximum sensitivity to the head can be achieved if the source of the probe is positioned directly above the fetal head. By optimizing the source-detector separation, the signal originating from photons that have traveled through the fetal head can drastically be increased.

Photon migration through fetal head in utero using continuous wave, near infrared spectroscopy: clinical and experimental model studies

Near infrared (NIR) measurements were made from the maternal abdomen (clinical studies) and laboratory tissue phantoms (experimental studies) to gain insight into photon migration through the fetal head in utero. Specifically, a continuous wave spectrometer was modified and employed to make NIR measurements at 760 and 850 nm, at a large (10 cm) and small (2.5/4 cm) source-detector separation, simultaneously, on the maternal abdomen, directly above the fetal head. A total of 19 patients were evaluated, whose average gestational age and fetal head depth, were 37 weeks +/- 3 and 2.25 cm +/- 0.7, respectively. At the large source-detector separation, the photons are expected to migrate through both the underlying maternal and fetal tissues before being detected at the surface, while at the short source-detector separation, the photons are expected to migrate primarily through the superficial maternal tissues before being detected. Second, similar NIR measurements were made on laboratory tissue phantoms, with variable optical properties and physical geometries. The variable optical properties were obtained using different concentrations of India ink and Intralipid in water, while the variable physical geometries were realized by employing glass containers of different shapes and sizes. Third, the NIR measurements, which were made on the laboratory tissue phantoms, were compared to the NIR measurements made on the maternal abdomen to determine which tissue phantom best simulates the photon migration path through the fetal head in utero. The results of the comparison were used to provide insight into the optical properties and physical geometry of the maternal and fetal tissues in the photon migration path.

Traumatic aneurysms and arteriovenous fistulas of the extracranial vessels in war injuries

BACKGROUND

Extracranial vessel injuries are potentially devastating complications of penetrating head and neck wounds associated with war conflicts. These vasculopathies may be occlusive or they may lead to formation of traumatic aneurysms (TA) and arteriovenous fistulae (AVF). Even though these penetrating injuries are usually clinically silent and often appear only as small superficial wounds, they may lead to catastrophic hemorrhage or vascular insult. In this study, we attempted to elucidate signs, symptoms and circumstances present in these victims who are at risk of harboring an occult vasculopathy, excluding the occlusive ones and concentrating primarily on TAs and AVFs.

MATERIALS AND METHODS

In a prospective study conducted during 8 years of war between Iran and Iraq, we encountered 13 cases of traumatic vasculopathies of the extracranial carotid and vertebral arteries. The type and number of injuries were: carotid-jugular fistula (CJF) 3, carotid trunk or branch aneurysm (CA) 2, superficial temporal artery aneurysm (STA) 3, vertebral artery aneurysm (VA) 2, vertebral arteriovenous fistula (VAVF) 1, ophthalmic artery aneurysm (Oph. An.) 1, and lingual artery aneurysm (Lin. An.) 1. Angiography was performed between the 5th and 30th day after the injury and surgical intervention was performed in all cases.

RESULTS

The Glasgow outcome scale (GOS) score was 13-15 in all victims at the time of discharge from the base hospital without any additional neurological deficit. The follow-up period varied from 5 to 8 years in all cases in whom no further morbidity or mortality occurred. Single photon emission computed tomography was the noninvasive tool used for measurement of cerebral blood flow in the cases in which a major vessel ligation was performed; no remarkable change in cerebral blood flow was noted.

CONCLUSION

Early recognition of stigmas suggesting possible formation of extracranial traumatic vasculopathies such as TAs or AVFs in the difficult situation of war frontier hospitals should be highlighted for attending physicians or younger neurosurgeons. Performing angiography promptly in suspected cases can pick up such traumatic vascular lesions earlier. Using simpler surgical techniques in situations in which more sophisticated endovascular equipment is unavailable can be life-saving for these usually young victims.

Selected interventional procedures for pediatric head and neck vascular lesions

Although vascular malformations are commonly seen in children, they are lesions managed best by an experienced multidisciplinary team. Recognizing, investigating, and diagnosing the type of vascular malformation is critical to determining treatment modality and pathway. Generic identification-despite Mulligan's excellent classification-or confusing vascular malformations with hemangiomas are both inappropriate because treatment is quite different for these separate groups of diseases. Additionally, an understanding of the recognition and classification of vascular malformations is essential for effective family counseling and management of these childhood lesions.

Symmetrical mutant phenotypes of the receptor EphB4 and its specific transmembrane ligand ephrin-B2 in cardiovascular development

Ephrin-B2 is a transmembrane ligand that is specifically expressed on arteries but not veins and that is essential for cardiovascular development. However, ephrin-B2 is also expressed in nonvascular tissues and interacts with multiple EphB class receptors expressed in both endothelial and nonendothelial cell types. Thus, the identity of the relevant receptor for ephrin-B2 and the site(s) where these molecules interact to control angiogenesis were not clear. Here we show that EphB4, a specific receptor for ephrin-B2, is exclusively expressed by vascular endothelial cells in embryos and is preferentially expressed on veins. A targeted mutation in EphB4 essentially phenocopies the mutation in ephrin-B2. These data indicate that ephrin-B2-EphB4 interactions are intrinsically required in vascular endothelial cells and are consistent with the idea that they mediate bidirectional signaling essential for angiogenesis.

Heating of tissue by near-field exposure to a dipole: a model analysis

We report a numerical study of the induced electric fields and specific absorption rate (SAR) produced by microwave radiation from a half-wavelength dipole near tissue models, and the resulting transient and steady-state temperature rises. Several models were explored, including a uniform semi-infinite plane of tissue, uniform sphere, a phantom model of the head filled with tissue-equivalent material, a numerical model of the head with uniform dielectric properties (obtained from a digitized computed tomography image), and a numerical model of the head with different dielectric properties corresponding to various tissues. The electromagnetic calculations were performed for half-wave dipoles radiating at 900 and 1900 MHz at various distances from the model, using the finite-difference-time-domain (FDTD) method. The resulting temperature rises were estimated by finite element solution of the bioheat equation. The calculated SAR values agree well with an empirical correlation due to Kuster. If the limiting hazard of such exposures is associated with excessive temperature increase, present exposure limits are very conservative and guidelines that are easier to implement might provide adequate protection.

Clinical experience in end-to-side venous anastomoses with a microvascular anastomotic coupling device in head and neck reconstruction

BACKGROUND

Microvascular anastomosis remains one of the most technically sensitive aspects of free-tissue transfer reconstructions. Despite the availability of various mechanical anastomotic coupling systems for human clinical use during the last 8 years, reported clinical series remain rare.

OBJECTIVE

To describe a clinical experience in applying a mechanical microvascular anastomotic coupling device (MACD) to end-to-side anastomotic configurations in head and neck free-flap reconstruction.

METHODS

The MACD is a readily available high-density polyethylene ring-stainless steel pin system that has been found to be highly effective in clinical studies of end-to-end arterial and venous anastomosis and in laboratory studies of end-to-side anastomosis of rabbit arteries.

RESULTS

Thirty-seven end-to-side venous anastomoses were attempted, of which 33 (89%) were completed. Of these, 9 patients had critical anastomoses (only 1 venous anastomosis per patient). In patients undergoing parallel venous anastomoses, 6 had both anastomoses performed using the MACD; in the remaining 12 patients, 1 of the anastomoses was performed using the MACD. A variety of donor flaps and clinical contexts were encountered. Flap survival in the MACD series was 100%. Four anastomoses were converted to conventional suture technique intraoperatively.

CONCLUSIONS

The MACD is well suited to end-to-side venous anastomosis when carefully and selectively used by experienced microvascular surgeons. The most common clinical situation requiring this configuration and technique was the lack of ipsilateral recipient veins for end-to-end anastomosis or a ligated internal jugular vein stump that required this approach for device application. Previous radiation therapy does not appear to be a contraindication to its use.

[Usefulness of percutaneous sclerosing treatment for low-flow vascular lesions]

Peripheral vascular lesions may occur as a result of various clinical problems, cosmetic or dysfunctional causes, or bleeding. In severe cases, coagulopathy and congestive heart failure may occur. Although the efficacy of transarterial embolization (TAE) for arterial vascular lesions is well known, TAE has no effect on low-flow vascular lesions (venous malformations, venous angiomas, and venous components of arteriovenous malformation). Therefore, in such cases, a percutaneous approach is the best method, and we consider sclerotherapy to be the most useful conservative treatment. The primary objective of this study was to confirm the efficacy of percutaneous sclerosing treatment for peripheral low-flow vascular lesions. Lesions were classified on the basis of state of blood flow and morphologic features, and infiltration was classified on the basis of angiographic features and magnetic resonance imaging (MRI) findings. In sclerosing treatment, we used 5% solutions of polidocanol, absolute ethanol, and N-butyl-2-cyanoacrylate (NBCA) as sclerosing agents. Each type of lesion, static or slow-flow, cystic, or localized, showed remarkable improvement after sclerosing treatment with only polidocanol. However, for moderate-to-fast-flow lesions, another sclerosing agent (absolute ethanol/NBCA) was needed. With diffuse infiltrative lesions, surgical repair might be needed, but we recognize the usefulness of sclerosing treatment for functional or cosmetic improvement in these cases.

Characterization of human head vasculature by percolation parameters

A data reduction procedure, originally proposed for characterization of fractals and random percolation clusters, has been used to evaluate the vascular system of the human head. The motivation behind this study arose from the wish to study empirically transport properties of vascular systems and to find a suitable formalism for their description. MR angiographic data acquired by a standard 3D inflow method were used. The evaluated parameters refer to the backbone fractal dimensionality and the correlation length. The fractal dimensionality of the backbone was found to be 1.71 for the human head vasculature. This value fits the theoretical range of random percolation networks. It is concluded that concepts of percolation theory might have some value for characterizing the structure and transport properties of the vascular system.

Effect of subcutaneous sumatriptan on head temperature in migraines

Sumatriptan, a selective 5-hydroxy-triptamine (5-HT1) receptor agonist, has been used recently in the treatment of acute migraine. Some in vitro experiments suggested that sumatriptan has vasoactive properties in vascular beds distinct from cerebral circulation. In view of this we investigated the vascular effects of the standard 6 mg subcutaneous (s.c.) dose of sumatriptan, on the surface areas of the head using thermography, a simple and reliable method for detecting temperature changes. The head temperature of 127 patients (double-blind), 102 migraines (52 during headache attack and 50 headache-free) and 25 healthy control subjects were evaluated using thermography in basal condition and 30, 60, 90, and 120 min after s.c. sumatriptan injection of placebo. During the entire observation period systemic blood pressure (SBP), heart rate (HR) and continuous electrocardiogram (ECG) were detected automatically. A significant head temperature decrease was observed after s.c. sumatriptan administration, in both healthy controls and migraine subjects; placebo administration did not show any change of temperature. In migraine patients during headache attack, head temperature reduction corresponded to the relief of headache symptoms. This vasoconstrictor effect detected with thermography is not isolated to cranial circulation but it is also systemic. In fact, we observed a significant increase (p < 0.05) in both systolic and diastolic systemic blood pressure. No significant changes in heart rate and ECG abnormalities were otherwise detected. These findings suggest that sumatriptan is effective in the treatment of migraine attack, but it must be used with caution in migraines with concomitant hypertension.

Head and neck vascular anomalies of childhood

Vascular anomalies of the head and neck are common lesions of childhood. The vascular anomalies can be divided into hemangiomas and vascular malformations. Each of these lesions has a characteristic imaging appearance. Correctly classifying the anomaly is essential in directing the treatment of these lesions.

Blood flow velocity changes in carotid and vertebral arteries with stellate ganglion block: measurement by magnetic resonance imaging using a direct bolus tracking method

BACKGROUND AND OBJECTIVES

Stellate ganglion block (SGB) leads to vasodilation of the head and neck, as a result of a regional sympathetic blockade. However, in such cases, controversy remains concerning changes in cerebral and extracerebral blood flow in the head. We estimated the effect of SGB on blood flow in the head by measuring the blood flow velocity in cervical vessels, using magnetic resonance imaging and the direct bolus tracking method. This noninvasive method is free from potential artifacts of bones and other connective tissues.

METHODS

Seven adult patients with acute or chronic pain in the head or neck underwent SGBs, using an anterior paratracheal approach with 6-8 mL of 1% mepivacaine (3 right and 4 left SGBs). Blood flow velocity in common carotid and vertebral arteries (CCA and VA) was measured simultaneously before and after SGB, using the direct bolus tracking method.

RESULTS

On the side of SGB, blood flow velocity in CCA significantly increased (P < .002), whereas velocity in VA was unchanged after SGB. On the side contralateral to the SGB, significant changes in blood flow velocity in CCA and VA were never observed.

CONCLUSIONS

Blood from the VA flows primarily to cerebral vessels, whereas that from CCA goes to both cerebral and extracerebral vessels. Given the presumed differences in blood flow distribution through the VA and CCA, we assume that the observed CCA blood flow increases, ipsilateral to the SGB, primarily as a result of vasodilation of extracerebral vessels and independent of changes in brain blood flow.

[Magnetic resonance angiography in diagnosis of head and neck vessels diseases]

Aiming to study diagnostic potential of MRA 286 patients have bean observed with pathology of the brain vessels. High efficiency of MRA has been confirmed: sensitivity and specificity with vascular malformations were 98% and 96%, with arterial aneurysm it was 97% and 82%, with stenosis of more than 50% it was 98% and 46%, with stenosis of less than 50% it was 96% and 84%, with thrombosis--100% and 100%. It was noted that TOF method is the most informative nature to estimate the arterial bed. We have managed to study with the PC method venous component of malformation, residual flow in huge thrombosed aneurysm, condition of the external carotid arteries and their branches.

Evaluation and treatment of head and neck venous vascular malformations

Congenital venous vascular malformations of the head and neck are low-flow, nonproliferative lesions that should be distinguished from hemangiomas. The characteristic history and clinical findings can establish the diagnosis. Direct percutaneous puncture and contrast injection at the time of treatment delineate the lesion and its drainage pattern. Treatment must be individualized according to lesion extent, patient tolerance and physician experience. Sclerotherapy with ethanol has proved to be a successful treatment modality for these lesions, as demonstrated in this study of 57 patients. Surgery is used for treatment of clinically significant residual disease. A multidisciplinary approach to evaluation and treatment is key to successful management.

Ephrin-A1 is expressed at sites of vascular development in the mouse

B61 (ephrin-A1), a ligand for eph receptor-protein tyrosine kinases, possesses angiogenic and endothelial cell chemoattractant activity. We report the expression profile of ephrin-A1 during mouse embryogenesis (7.25 to 10.5 days post-coitum (dpc)). Ephrin-A1 expression was first detected in the caudal end of the primitive streak and the developing allantois. At mid head fold stage, ephrin-A1 transcripts were observed in the anterior pharyngeal endoderm that underlies the site of the future heart. In 8.0 to 8.5 dpc embryos, ephrin-A1 was expressed in presumptive endocardial cells, the dorsal aorta, and the primary head veins. In 9.5 to 10.5 dpc embryos, ephrin-A1 RNA was detected in intersomitic vessels and the limb bud vasculature. Each site of ephrin-A1 expression corresponded to regions of vasculogenesis and/or angiogenesis.