External Carotid System Research Articles

Development of the facial midline.

"Intellectual excellence lies in having faith in the observation of apparently nontranscendental and unimportant facts. To observe an anatomic element calmly, with an open, analytical spirit, and with spiritual freedom, can lead to an explosive vortex of new knowledge."-Miguel Orticochea, M.D.(1) Traditional descriptive embryology based upon the interaction of frontonasal, lateral nasal, and medial nasal prominences is incapable of explaining the three-dimensional development of the facial midline. The internal structure of the nose and that of the oronasal midline can best be explained by the presence of paired A fields originating from the prechordal mesendoderm, associated with the nasal and optic placodes, supplied by the internal carotid artery, and sharing a common genetic coding with the prosomeres of the forebrain. Mesial drift of these fields leads to fusion of their medial walls; this in turn provides bilateral functional matrics within which form the orbits ethmoids, lacrimals, turbinates, premaxillae, vomerine bones, and the cartilages of the nose. This two-part paper reports six lines of evidence supporting the field theory model of facial development: (1) An apparent watershed exists in the midline of the base between the territories of the internal and external carotid systems. Isolation of the ICA in injected fetal specimens confirmed that the demarcation was distinct and restricted to the embryonic nasal capsule. (2) Field theory explains the developmental anatomy of the contents of the nasal capsule. (3) The neuromeric model of CNS development provides a genetic basis for the anatomy and behavior of fields. (4) Mutants for the Dlx5 gene demonstrate A field deletion patterns. These experiments relate the nasal placode to the structures of the A fields. (5) Separate regions of the original nasal placodes give rise to neurons, which are dedicated to separate sensory and endocrine systems. The A fields constitute the pathways by which these neurons reach the brain. (6) Non-cleft lip-related cleft palate, holoprosencephaly, and the Kallmann syndrome are clinical models that demonstrate the effects of anatomic disturbances within the A fields.

Steno-occlusive changes in the external carotid system in moyamoya disease.

To evaluate the steno-occlusive changes in the external carotid system in moyamoya disease, cerebral angiograms of 39 moyamoya patients were retrospectively reviewed. There were 26 females and 13 males, age ranged from 4 to 62 years with a mean of 26 years. Initial symptoms were ischaemia in 27 patients, haemorrhage in 9, and none in 3. Stenosis, occlusion, and dilatation in the external carotid system were analysed angiographically. No stenosis or occlusion of the superficial temporal artery, middle meningeal artery, or occipital artery was observed in either preoperative or postoperative follow-up angiograms in any patients. Steno-occlusive changes do not occur in the external carotid system, but are confined in the internal carotid system in moyamoya disease.

Asystole During Endovascular Embolization of a Dural Arterio-Venous Fistula in the Brain

Asystole During Endovascular Embolization of a Dural Arterio-Venous Fistula in the Brain

Reversible dementia due to dural arteriovenous fistula: A simple surgical option

Dural AVMs can produce a wide variety of symptoms related to raised intracranial pressure, venous congestion, and cerebral ischaemia. We present a unique case of reversible dementia, due to venous hypertension. The cerebral ischaemia was caused by extensive bilateral arteriovenous malformations of the external carotid system, which drained into the superior sagittal and transverse sinuses and resulted in venous hypertension. Although partial occlusion by endovascular embolization and ligation procedures had some effect, only 'scalping and silastic implantation' gave satisfactory amelioration of symptoms.

Cerebral blood flow measurement as an indicator for an indirect revascularization procedure for adult patients with moyamoya disease.

Some adult patients with moyamoya disease have been treated successfully by indirect revascularization alone, although surgical indications and hemodynamic changes for these patients have not been fully explored. To examine surgical indications for this procedure, we studied the regional cerebral blood flow (rCBF) and angiographic findings in adult patients with moyamoya disease preoperatively and postoperatively. On 17 hemispheric sides of 12 adult patients with moyamoya disease treated surgically with a combination of various indirect procedures, mainly by encephaloduroarteriosynangiosis, we retrospectively evaluated changes in rCBF using xenon-133 single photon emission computed tomography, angiographic collateral formation, and clinical results. Preoperatively, the rCBF values in the cortices at the bypass site at rest and after acetazolamide loading were lower than normal. The rCBF values were significantly increased after revascularization, approaching normal, except for incomplete recovery of vascular reactivity. The extent of postoperative neovascularization from implanted tissues fed by the external carotid artery system was more developed, in parallel with the preoperative decrease in resting and loading rCBF values. One-third of the operated sides exhibiting both a low rCBF at rest and impaired vascular reactivity in the noninfarcted cortices achieved good revascularization over two-thirds of the middle cerebral artery territory, accompanied by rCBF improvement and moyamoya vessel regression. Enough potential for neovascularization in the noninfarcted cortices was indicated that the resting rCBF was lower than 50 ml/100 g per minute (below the normal value by 2 standard deviations) and did not increase more than that value after loading, even in a 40-year-old patient who presented with a hemorrhage. Clinically, 11 patients (92%) had good results at the 4-year follow-up, whereas 1 patient (8%) with unsatisfactory neovascularization and a lesser extent of moyamoya vessel reduction experienced rebleeding. We conclude that for the surgical treatment of adult patients with moyamoya disease, indirect procedures, mainly encephaloduroarteriosynangiosis, are recommended for patients with lower rCBF and no or negative vascular reactivity in the noninfarcted cortices, as well as for those who have no indication for the direct procedure. It is possible to determine these indications by a xenon-133 inhalation single photon emission computed tomographic study including an acetazolamide challenge test.

Angiographic study of Moyamoya disease and histological study in the external carotid artery system

A total of 13 cases of Moyamoya disease were verified by internal and external carotid artery angiography. The biopsy samples were taken from the superficial temporal arteries and middle meningeal arteries in 12 and six cases, respectively. Angiographical and histological studies revealed that both of the internal and external carotid system could be involved in Moyamoya disease. Our studies demonstrated that Moyamoya disease was a type of vascular disease not only confined to the cerebral vessels. We recommend angiography of external carotid system and extracranial segment of internal carotid artery while performing three vascular angiography. Whether superficial temporal artery has been involved in angiography can be used as an indication of indirect cerebrovascular bypass.

Dural arteriovenous fistulas including the transverse and sigmoid sinuses: results of treatment in 30 cases.

We report about the treatment and outcome of 30 patients with dural arteriovenous fistulas including the transverse and sigmoid sinuses treated between 1986 and 1995. All patients underwent panangiography for definitive diagnosis. The dAVF were supplied by the external carotid artery system alone (14 patients), both external and internal carotid systems (10 patients) or both anterior and posterior circulation (6 patients). Depending on the venous drainage the fistulas were classified following a modification of Djindjian's description with 18 patients revealing Type I (main sinus with antegrade flow), 5 Type II a (main sinus with reflux into the contralateral sinus). 5 Type II b (cortical veins), 1 Type II a+b (both) and 1 of Type III (direct cortical drainage). Bruit, pulsatile tinnitus and headaches were the most common symptoms. 6 patients presented with intracranial haemorrhage, 4 with progressive neurological deficit or seizures and 3 with dementia. Arterial embolization was performed in all cases except one, where a transvenous approach for balloon occlusion of the transverse sinus was performed. 21 patients were treated by single or repeated embolization alone. Only in 9/21 cases did arterial embolization result in complete occlusion of the fistula. In 12/21 patients incomplete occlusion was achieved. Following embolization 8 patients underwent additional surgery including coagulation of the feeding arteries and arterialized veins, sinus resection and reconstruction of the sinus. Overall, 18 patients were cured, 11 improved and 1 patient was unchanged. There was a total number of 5 complications including transient stroke, transient facial nerve palsy, and a small necrotic skin area following embolization. Venous infarction of the occipital lobe was induced by transvenous occlusion and surgical resection of the transverse sinus in one patient each, respectively. From our results we conclude that the endovascular therapy alone is the treatment of choice in case of Type I fistulas. In dAVF of Type II and III repeated endovascular treatment seems not to be sufficient and additional surgery is necessary.

The effect of CO2 and apnea on cochlear and middle ear blood flow in guinea pigs

The effect of 10% CO2 (in air) and apnea on cochlear blood flow (CBF) and middle ear blood flow (MEBF), capillary vessel diameters and blood pressure (BP) were investigated in guinea pigs. Intravital microscopic techniques (IVM) using video system, and laser Doppler flowmetry (LD) were used. MEBF was measured in the blood vessels of the middle ear mucosa over the cochlea and CBF was measured in the lateral wall vessels in the second or third cochlear turn. During 10% CO2 respiration for 10 min, the highest vessel diameter dilated about 11% in the middle ear and 5% in the cochlea. During 5 minutes apnea, the highest vessel diameter constricted about 30% in the middle ear and 5% in the cochlea. Elevation of PCO2 dilate blood vessels with constant PO2, but constriction of blood vessels as observed in extremely low PO2 range even if PCO2 was elevated. The ratio of the change in blood flow volume to the change in BP was obtained after the change in blood flow volume was calculated from blood flow velocity and blood vessel diameter. The mean change of ratio in MEBF was a 10% decrease with 10% CO2, 28% decrease with apnea in IVM. The mean change of ratio in CBF was a 44% increase with 10% CO2, 14% increase with apnea in IVM, 67% increase with 10% CO2, 42% increase with apnea, in LD. The change of CBF in LD was about 20% larger than in IVM. Our results showed that CBF belonging to vertebral artery system was more strongly maintained in association with autoregulation even under conditions of low PO2 or high PCO2 compared to MEBF in the external carotid artery system. It was suggested that blood flow behavior was significantly different between the middle ear and inner ear.

Dural Arteriovenous Shunts Involving the Sphenoparietal Sinus

A 40-year-old male suffered transient global amnesia and was diagnosed as having a very rare location of dural arteriovenous shunt (dAVS) involving the right sphenoparietal sinus. The feeding pedicles of dAVS were not only arising from the right external carotid system, including the middle meningeal artery, but also the right internal carotid system including the ophthalmic artery. The dAVS drained into the right sphenoparietal sinus, right vein of Labbe, and right basal vein of Rosenthal through numerous dilated temporal cortical veins. The arteriovenous shunt itself was located at the dura around the right superior ophthalmic fissure and a large varix received direct shunting blood flow from the right sphenoparietal sinus. The dAVS was cured by drainer clipping following transarterial embolisations. A dAVS with cortical venous drainage is considered to have a higher risk of haemorrhage and venous infarction than the others and thus warrants treatment even if the clinical symptom is minimal. If the dAVS has a single drainer, it will be easily cured by way of drainer clipping. Preoperative embolisation makes clipping easier and safer. Intraoperative angiography is useful because preoperative angiography may not necessarily show the complete angioarchitecture around the lesion.

Angiography and transcatheter arterial embolization of vascular injuries of the face and neck.

The condition of patients sustaining penetrating neck trauma often appears deceptively stable, even when major structures have been injured. The clinician must identify patients who require treatment and limit invasive procedures in those without significant injuries. Angiography is often used to search for vascular damage following penetration of the neck and face. The charts of 401 hemodynamically stable patients with penetrating cervicofacial wounds who were evaluated by angiography followed, when necessary by either transcatheter arterial embolization and observation or surgery were reviewed. One hundred twelve patients (27.9%) had 131 vascular injuries identified by angiography; 77 (68.8%) of these patients sustained injuries to zone III of the neck or the face. The most commonly injured vessels were the internal carotid artery (ICA), the vertebral artery, and the external carotid artery (ECA) system. Multiple vessel injuries were seen in 17 (15.2%) of 112 patients and were more likely in patients with wounds in zone III or above than in those wounded in zone II or below (20.8% vs. 2.9%, respectively; P < .025). Injuries to the internal maxillary artery (IMA) (60%), ECA (53.3%), and the ICA (30.8%) were also significantly more likely to be accompanied by additional vascular injuries (P < .005). No clinically significant venous injuries were missed. Complications were noted in only 4 patients, and no deaths occurred as a result of angiography. Angiography is a safe, effective modality in the head and neck trauma setting. Particular scrutiny should be given to patients with zone III or facial wounds, particularly those with documented ICA, IMA, and ECA injuries, since these patients have a higher incidence of multiple vascular injuries.

Pitfalls during the Embolization and Evaluation after the Embolization for the Skull Base Meningiomas

Pitfall during the embolization and evaluation after the embolization for skull base meningiomas supplied by meningeal arteries of internal carotid artery (ICA) are reported. This study includes 15 cases of skull base meningiomas (two males and 13 females) that supplied by meningeal branches of internal carotid artery. The preoperative embolization was performed by these feeders. MRI findings and serum levels of C-reactive protein (CRP) after the embolization were examined. In ten patients among 15 patients the meningeal branches of ICA were dominant feeders. In ten patients out of 15 patients, the embolization from the meningeal branches of ICA was possible. Eight patients out of these ten patients were suffered from high fever and increase of serum level of CRP after the embolization. During the embolization for skull base meningiomas, the existence of collateral pathways between the ICA system and external carotid artery system were identified. The increase of serum levels of CRP might be recognized in the patients that effective embolization were performed.

Management of Orbital and Periorbital Arteriovenous Malformations

Arteriovenous malformations (AVMs) of the orbit are progressively enlarging communications between arteries and veins that bypass normal capillary beds. In contrast to arteriovenous fistulas (AVFs), AVMs are congenital lesions with multiple large feeding arteries, a central nidus, and numerous dilated draining veins. Management of AVMs of the orbit may be difficult due to the threat of hemorrhage, vascular occlusion during treatment, and collateral damage to surrounding organs. We managed AVM of the orbit and periorbital tissues in four patients. Neuroimaging studies, clinical decision making, operative experience, and long-term postoperative results were retrospectively reviewed. Four cases of AVM of the orbit and periorbital tissues were successfully treated with preoperative embolization and subsequent excision of the central nidus of the AVM. There was no evidence of recurrence in any of the cases over follow up ranging from 2 to 5 years. We conclude that identification of all arterial feeders, from both internal and external carotid systems, is critical in developing a therapeutic plan. AVMs may be treated by surgical excision alone, or embolization alone. However, in the hands of an experienced interventional neuroradiologist and an appropriately chosen surgical team, most AVMs can and should be treated by a combined approach of preoperative embolization followed by surgical excision of the vascular mass. The goal of therapy is closure of the low-resistance shunt.

Facial arteriovenous malformation associated with consumption coagulopathy treated by embolization: Report of case

A rare case of facial arteriovenous malformation (AVM) associated with consumption coagulopathy is reported. The AVM was fed solely by the external carotid arterial system with an extensive arteriovenous shunt. Laboratory testing showed prolongation of the partial thromboplastin time (PTT), and low factor VIII. The level of factor VIII became normalized after multiple embolizations concomitant with reduction of the AVM. Although embolization of facial AVM is controversial, it is one of the treatments of choice, especially when there is an associated coagulation abnormality.

Effect of multiple ligations of the external carotid artery and its branches on blood flow in the internal maxillary artery in dogs

The effect of occlusion of the external carotid system on blood flow of the internal maxillary artery was investigated in 16 dogs. The external carotid system was occluded by ligation or clamping at different levels separately or simultaneously and the blood flow of the internal maxillary artery was measured with an electromagnetic flowmeter before and after each occlusion. The ligation of the external carotid artery below (low ligation) and above (high ligation) the origin of the occipital, lingual, and facial arteries reduced the blood flow by 61.1% and 71.5%, respectively. Low ligation together with ligation of the lingual artery reduced the blood flow by 73.5%. Multiple ligations (high and low ligations combined with ligations of the occipital, lingual, and facial arteries) reduced the blood flow by 81.8%. The internal maxillary artery was sectioned after the multiple ligations, and retrograde flow from the distal segment was studied. The flow was only a trace and could not be measured with the flowmeter. Total blood loss from both ends almost equaled the blood flow of the proximal segment, 18.2% of normal. Multiple occlusion appears to be the most effective treatment for hemorrhage from the initial part of the internal maxillary artery.

Detection of Carotid Stenosis by Physicial Examination

To the Editor. — In their recent article, 1 Dr Sauve and colleagues discuss the relationship between high-grade stenosis and carotid bruit, stating, Unfortunately, however, this relation is not strong enough for the clinician to be able to use the presence of a bruit to rule in, or the absence of a bruit to rule out, high-grade carotid stenosis. This is an erroneous statement. Clinicians understand that some patients with high-grade stenosis do not have a carotid bruit. However, most competent neurologists who diagnose and treat vascular disease of the brain are aware that a carotid bruit extending into diastole indicates a high degree of stenosis in the carotid artery. The examiner cannot differentiate whether the high-grade stenosis is in the external carotid system or the internal carotid system, but most often it is in the latter system. The misleading statement in this article will reduce the use of carotid

吸収性縫合糸polydioxanone (PDS) を用いた連続縫合によるSTA-MCA吻合術

To minimize the temporary occlusion time during bypass surgery, continuous absorbable sutures with 9-0 polydioxanone (PDS) were employed in the superficial temporal artery-middle cerebral artery (STA-MCA) anastomoses. Two cases of internal carotid artery occlusion and 4 cases of its stenosis were operated on in the chronic stage, and one case of MCA occlusion in the superacute stage. In all cases, a cold xenon-enhanced CT revealed the reduction of local cerebral blood flow (LCBF) preoperatively. Postoperative courses were uneventful and there were no anastomotic complications. The follow-up period ranged from 6 to 14 months. In 5 of the 6 cases in the chronic stage, all STAs and anastomotic sites grew remarkably in diameter 3 months after the surgery, when PDS had already lost tensile strength, and thereafter gradually increased in size. These changes were correlated with the improvement of LCBF. In the remaining one in the chronic stage, the STA showed less growing due to increased collateral flow via the external carotid artery system. In the case of MCA occlusion, growing of STA did not occur due to the low bypass-flow that resulted from the spontaneous recanalization of the occluded MCA. Previous studies suggested that absorbable PDS does not elicit inflammatory response, wall thickening, hyalinoid degeneration or calcification, which occasionally occur in use of nonabsorbable polypropylene sutures. In conclusion, PDS seems to be suitable for anastomosing small vessels and continuous PDS sutures are available for extracranial-intracranial arterial bypass surgery in which anastomotic sites grow corresponding to the increases of the bypass-flow.

Variations of the middle meningeal artery: Significance for surgery and practice

AbstractThe origin and branching of the middle meningeal artery (MMA), as well as the length and development of its three main branches, were analyzed by following the arterial sulci on skull bones. We examined 186 macerated skulls (128 male and 58 female). Variations were classified into nine types. Some of the previously ignored communications of the branches of MMA with other arteries of the external carotid systems such as the deep temporal a., deep auricular a., occipital a., and anterior tympanic a. are described. © 1993 Wiley‐Liss, Inc.

Recipient vessels for microvascular transplants in patients with hemifacial microsomia.

Hemifacial microsomia is a developmental abnormality involving structures derived from the first and second branchial arches. Microvascular transplants are increasingly being used to improve facial contour in patients with this condition. We have reviewed 9 patients with this abnormality to determine which recipient vessels have been used. In 6 patients, the facial vessels were located and used for flap revascularization. In 3 patients, the facial vessels could not be identified intraoperatively, and the occipital artery and a branch of the external jugular vein were used as recipient vessels. In this series of hemifacial microsomia patients, therefore, the facial vessels could not be located in 3 patients. We recommend that surgeons performing microsurgical transplants in cases of hemifacial microsomia be prepared to explore the external carotid and external jugular systems for recipient vessels.

Childhood moyamoya disease before and after encephalo-duro-arterio-synangiosis: an angiographic study.

Encephalo-duro-arterio-synangiosis (EDAS) is a new surgical operation for childhood moyamoya disease, and its effects have been studied by comparing pre- and postoperative angiograms in 27 patients. The development of collaterals from the external carotid arterial system into the territory of the middle cerebral artery was excellent in 16 of 54 cerebral hemispheres after EDAS, good in 25, and poor in 13. The development of collaterals after EDAS increased as the stenotic process in the internal carotid artery on preoperative angiograms increased except in the most advanced cases, where it seemed to decrease in comparison with the group with middle grade stenosis. After EDAS, not only the superficial temporal artery, but also the adjacent middle meningeal artery participated in forming collateral pathways. Furthermore, decrease of abnormal net-like vessels was observed when there was good to excellent development of collateral vessels. Stenotic lesions in the internal carotid and posterior cerebral arteries were often seen to progress, indicative of the rapidly progressive nature of childhood moyamoya disease. These results appear to suggest that EDAS should be performed as early as possible in childhood moyamoya disease before the occurrence of an irreversible ischaemic state and/or permanent neurological defects.

Carotid Endarterectomy

Many factors influence cerebral circulation in addition to carotid blood flow. The brain accounts for less than 2% of body weight but consumes 20% of the total circulation. Cerebral blood is not transported passively. Rather, complex control systems in the brain vasculature maintain almost constant total cerebral blood flow within a wide range of levels of systemic blood pressure and distribute circulation within the brain unevenly according to local metabolic needs. Signals that originate in pressure sensors in supply arteries initiate changes in systemic blood pressure and adjust resistance in cranial vasculature. These reflexes modify the direction of flow in extracranial arteries. Collateral channels bridge internal to external carotid and vertebral systems. Intracranial arteries link hemispheres, connect carotid and basilar artery territories, and—on the brain surface—join branches of middle cerebral, anterior cerebral, and posterior cerebral arteries. Within these vascular territories, blood flow is coupled to local brain metabolism. Parenchymal arteriolar