Intratumoral injection of cyanoacrylate glue in head and neck paragangliomas.

BACKGROUND AND PURPOSE: Substantial intraoperative bleeding during surgical removal of head and neck paragangliomas may be a major problem in the management of these highly vascularized tumors. Traditional preoperative embolization via a transarterial approach has proved beneficial but is often limited by complex vascular anatomy and unfavorable locations. We report our experience with the preoperative devascularization of head and neck paragangliomas by using direct puncture and an intralesional injection of cyanoacrylate. METHODS: We retrospectively analyzed nine consecutive patients with head and neck paragangliomas who were referred for preoperative devascularization. Three patients were treated for carotid-body tumors; two for vagal lesions; and four, for jugular paragangliomas. Direct puncture of the lesion was performed by using roadmap fluoroscopic guidance. Acrylic glue was injected by using continuous biplane fluoroscopy. All patients underwent postembolization control angiography and immediate postoperative CT scanning. RESULTS: Angiograms showed that complete devascularization was achieved in all cervical glomus tumors, whereas subtotal devascularization was achieved in jugular paragangliomas. In this latter location, the injection of acrylic glue was limited by the potential risk of reflux into normal brain territory via feeders from the internal carotid or vertebral artery. The tumors were surgically removed and histologically examined. No technical or clinical complications related to the embolization procedure occurred. CONCLUSION: Percutaneous puncture of paragangliomas in the head and neck region and their preoperative devascularization by intralesional injection of acrylic glue is a feasible, safe, and effective technique.

Aortico-pulmonary bodies in the domestic fowl: ultrastructure, innervation and secretion.

In adult and immature domestic fowl, aggregations of large pale-staining cells were found in the wall of the aorta, and of the pulmonary trunk and arteries, in modified regions typified by interruption or loss of elastic laminae and smooth muscle cells. Encapsulated extramural aggregations of similar cells were identified either on the actual surface or well outside the arterial wall of the aorta, and pulmonary trunk and arteries. The electron microscope revealed that the pale cells in these intramural and extramural structures were granular cells characterised by dense-cored vesicles typically about 60-140 nm in diameter. Supporting cells partly invested the granular cells. These intramural and extramural structures are interpreted as aortico-pulmonary bodies. The extramural and to a lesser extent the intramural cells were associated with many axonal endings and fenestrated blood capillaries. The axonal endings formed presumptive afferent, efferent and reciprocal synapses with the granular cells. Both intra- and extramural granular cells displayed evidence of exocytosis and were also shown by autoradiography to handle amines. It is concluded that the ultrastructural features of these aortico-pulmonary bodies resemble those of the carotid body. It is therefore suggested that the aortico-pulmonary bodies of the domestic fowl have a chemoreceptor function similar to that of the carotid body. It is also suggested that they may have a general secretory function.

Quantitative studies of the aortic bodies of the cat. I. Point-counting analysis of tissue components.

Electron micrographs of cat aortic bodies were submitted to point-counting analysis to determine the volume/volume densities (vv%) of general tissue components. Paraganglia, enclosed by a perineural sheath (endoneural paraganglia), exhibit a significantly higher density of specific tissue elements (type-I cells, type-II cells, nerves) than those which covered by fibroblasts (exoneural paraganglia). Additional criteria which allowed distinction of these types of aortic bodies were not evident in this study. On average, type-I cells occupied 27.8 vv% if related to the entire organ, or 35.6 vv% if related to the blood vessel-free space. Comparing our data with those reported for the carotid body, we found an about twofold amount of type-I cells within aortic bodies. The relevance of this finding is discussed with respect to the known different electrophysiological properties of carotid and aortic body arterial chemoreceptors.

Role of arterial O2 flow in peripheral chemoreceptor excitation.

Assurance of adequate oxygen flow is a fundamental issue for all oxygen-consuming organisms. In higher organisms, aortic and carotid body chemoreceptors are known to sense arterial hypoxia, but the factors that allow aortic and carotid body chemoreceptors to sense the level of O2 circulation deserve further clarification. Experiments in the cat are presented in which the activity of chemoreceptor afferents from aortic and carotid bodies was monitored while arterial O2 flow was manipulated by i) lowering PaO2, ii) carboxyhemoglobinemia, iii) anemia, and iv) lowering systemic blood pressure. All of the above alterations stimulated aortic body chemoreceptors, indicating that hemoglobin-bound O2 participated in the maintenance of the receptor PO2 level. In contrast, most carotid body chemoreceptors were not stimulated by moderate carboxyhemoglobinemia, anemia and/or hypotension, indicating that hemoglobin-bound O2 normally did not influence the receptor tissue PO2. However, hypotension at a low O2 capacity did stimulate the receptors. In aortic body circulation, O2 flow was already critical, and therefore the chemoreceptors were sensitive to O2 transport capacity whereas carotid body chemoreceptors were not, presumably because of a large blood flow. Accordingly, aortic body chemoreceptors are more suited for monitoring circulatory O2 flow and carotid chemoreceptors for respiratory O2 flow.

The aortic bodies supplied by coronary arteries in the dog. Their contribution to the hypertensive response that follows serotonin injection.

I assessed the role of the chemoreceptors (aortic bodies) supplied by the coronary arteries in the hypertensive response induced by left atrial injection of (200 microgram serotonin) in adult anesthetized dogs. I compared the pressor response induced by serotonin during normal coronary circulation with that during exclusion of the central coronary segments from which the coronary blood supply to the aortic bodies arises. Exclusion of the central segments reduced the pressor response significantly from the control responses. Exclusion of the coronary blood supply of the aortic bodies resulted in a reduction of the control response of more than 50% in only two of the 21 dogs. I conclude that although the aortic bodies supplied by the coronary arteries play a significant role in the total hypertensive response to injected serotonin, their role usually is not predominant.