Histological demonstration of healing in experimental aneurysms.

INTRODUCTION: Recanalisation of aneurysms after interventional therapy is still an unsolved problem. The aim of this study is to demonstrate the angiographic and histological evidence of healing after endovascular embolisation of experimental aneurysms. METHODS: We evaluated the healing reaction in experimental aneurysms treated with HydroCoils and platinum coils. After microsurgical construction of aneurysms in 24 rabbits, embolisation was performed. Four animals were sacrificed immediately after embolisation and 5 after 1 month, 3 months and 6 months, respectively, the remaining served as control group. Serial plastic-embedded ground sections of the parent arteries-aneurysm complexes were evaluated by light microscopy. RESULTS: Thrombus organisation in the aneurysms resulted in fibrovascular tissue formation between bare platinum and HydroCoils from the walls of the aneurysms towards the centre of the sac over time. In the clefts between HydroCoils only thin strands of granulation tissue were observed. From one month on, there was a neointimal layer covering the coil mass at the aneurysm orifice. CONCLUSION: Progressive occlusion by the expanding hydrogel polymers on the coils seemed to result in a durable healing reaction in the aneurismal sac in a short-term follow-up period.

Computerized Angiographic Occlusion Rating for Ruptured Clipped Aneurysms is Superior to Subjective Occlusion Rating.

BACKGROUND AND PURPOSE: The computerized occlusion rating to estimate angiographic occlusion of embolized aneurysms is superior to the subjective occlusion rating. In this study, we compared the 2 methods in the analysis of aneurysms clipped after subarachnoid hemorrhage. MATERIALS AND METHODS: The pre- and postoperative angiographic images (DSA) of 95 selected patients were analyzed and stratified in 4 grades (grade 0 for 100%, grade I for <99%-90%, grade II for <89%-70%, grade III for <70% occlusion) by using the subjective (angiographic) occlusion rating and the computerized (angiographic) occlusion rating. For the subjective occlusion rating, the occlusion rate was estimated; for the computerized occlusion rating, the "occluded" and "nonoccluded" aneurysm areas were automatically calculated in square millimeters after outlining the ideal occlusion line. RESULTS: With the subjective occlusion rating, 75 (78.9%), 12 (12.6%), 7 (7.4%), and 1 (1.1%) and with the computerized occlusion rating 45 (47.4%), 24 (25.3%), 20 (21.0%), and 6 (6.3%) patients had aneurysms stratified to grades 0, I, II and III, respectively. The interobserver variation was significant with the subjective occlusion rating but not with the computerized occlusion rating. The subjective occlusion rating overestimated aneurysm occlusion in 30 (31.6%) patients. Mean values were the following: subjective occlusion rating of 97.5 ± 6.3% and computerized occlusion rating of 93.5 ± 9.7%; P = < .001. No patient rebled, and 4 patients underwent retreatment during 36 ± 38.9 months; the predictive value (log-rank, Kaplan-Meier) of the subjective and computerized occlusion ratings with respect to retreatment was highly significant for both methods (subjective occlusion rating: χ(2), 29.65; P < .001; computerized occlusion rating: χ(2), 35.57, P < .001). CONCLUSIONS: The 2 methods showed remarkable differences in the estimation of the angiographic occlusion rates of clipped aneurysms. The clearly lower interobserver variation of the computerized versus subjective occlusion rating may indicate a superiority of the computerized occlusion rating.

Diagnostic and therapeutic approaches to carotid body tumors. Review of 24 patients.

OBJECTIVE: To determine the clinical characteristics of carotid body tumors to define better a standardized proceeding in the management of carotid body tumors. DESIGN: Retrospective survey. Duration of postoperative follow-up was 4 months to 16 years (median, 57 months). SETTING: Institutional, tertiary care medical center. PATIENTS: Consecutive sample of 24 patients (10 men and 14 women) with 28 carotid body tumors treated in the University of Vienna (Austria) General Hospital in 35 years. INTERVENTIONS: Surgical resection, preoperative embolization. MAIN OUTCOME MEASURES: Initial signs, duration of symptoms, extension of the tumors, methods of investigations, and treatment modality, with special respect to the operative technique. RESULTS: Doppler color flow imaging and angiography provided essential mainstays for definite diagnosis. Computed tomography and magnetic resonance imaging contributed additional information about tumor extension. Nineteen patients (79%) underwent surgical resection of 22 tumors, 8 (42%) after preoperative embolization. There were no perioperative deaths. Hemiplegia occurred in 1 patient, and cranial nerve palsy occurred in 5 patients. Tumor recurrence was observed in 3 patients. Five patients refused surgery or tumors were unresectable. CONCLUSIONS: Our standard diagnostic procedure consists of establishing diagnosis by Doppler color flow sonography, angiography for detailing the vascularization of the tumor, and selective embolization to enable safer surgery with less bleeding. Early surgery is recommended to minimize major risks.

Repermeation of partially embolized cerebral arteriovenous malformations: a clinical, radiologic, and histologic study.

PURPOSE: To describe the pattern and time course of embolization-related tissue lesions and repermeation of the intranidal cast after endovascular embolization of cerebral arteriovenous malformations (AVMs) with N-butyl cyanoacrylate (NBCA). METHODS: We retrospectively reviewed the records of 26 patients who were treated by endovascular embolization with NBCA and subsequent surgical extirpation to look for embolization-related tissue lesions and repermeation of the cast. A residual flow through the malformation was identified on preoperative angiograms in every case. RESULTS: Pattern and time course of embolization-related tissue lesions were typical. Until 3 months after embolization, repermeation of embolized structures did not occur. In contrast, repermeation was found in every patient who had surgery later than 3 months after the first embolization (n = 13; 50%). In these cases, histologic examination of the resected nidus disclosed capillary structures inside the lumen of embolized vessels. Capillaries were traced immunohistochemically with antibodies against membrane-bound factor VIII. No parameter other than the interval between the first embolization and surgery was found to relate to the repermeation of the cast. CONCLUSION: Intranidal recapillarization can occur later than 3 months after the first embolization with NBCA if total and solid casting of the nidus was not accomplished.

Endovascular therapy of idiopathic cavernous aneurysms over 11 years.

PURPOSE: We report our experience with 42 patients with 48 cavernous carotid aneurysms, of whom 32 were treated with endovascular techniques and 10 were managed conservatively. METHODS: The 48 aneurysms were divided into two subgroups by location: 23 were at the C-3 portion of the carotid artery (small, saccular aneurysms with an epidural, partly intracavernous location) and 25 originated at the C4-5 segment (large or giant often fusiform aneurysms with a true intracavernous location). Morphologic features in both groups correlated well with differences in clinical presentation and also influenced therapy. Sixteen of the 25 C4-5 aneurysms (all large or giant) were treated by balloon occlusion of the parent artery, four (with narrow necks) were treated with Guglielmi detachable coils (GDCs), and five were not treated (asymptomatic or minimally symptomatic). Twelve of 13 C-3 aneurysms were treated with GDCs. Ten C-3 aneurysms were not treated. RESULTS: Ophthalmoplegia resolved or improved in nine of 12 patients treated with parent artery occlusion. All aneurysms treated by carotid occlusion thrombosed. Twelve of the 17 aneurysms treated with GDCs were 100% filled by the coils, four were 80% to 95% filled, and one was only 40% filled. Seven of the 100% filled aneurysms remained completely occluded, two showed slight coil compaction, and in three, follow-up angiography was not available. Among the incompletely filled aneurysms, two remained unchanged, one showed progressive thrombosis, a fourth revealed coil compaction, and in one, follow-up angiography was not available. One thromboembolic stroke and three transient ischemic attacks occurred perioperatively, for a permanent morbidity of 3.5% and a transient morbidity of 9%. There was no mortality. Mean clinical follow-up was 33 months; mean angiographic follow-up of patients treated with GDCs was 11 months. CONCLUSION: Surgically difficult cavernous aneurysms can be obliterated by embolization with excellent clinical results. Detachable coils have become an important endovascular tool, especially for narrow-necked cavernous aneurysms of the C-3 segment, which can be protected against rupture in the subarachnoid space in most cases.

Clinical and angiographic results of endosaccular coiling treatment of giant and very large intracranial aneurysms: a 7-year, single-center experience.

OBJECTIVE: To evaluate whether the objectives of surgical treatment, i.e., prevention of aneurysmal rebleeding, relief of aneurysmal mass effect, and prevention of embolic complications, are met by endosaccular coiling treatment applied to giant and very large wide-necked aneurysms. METHODS: Thirty patients with 31 giant or very large aneurysms were considered to show unacceptable risk/benefit ratios for open surgery and were treated using the Guglielmi detachable coil (GDC) method between 1992 and 1998. RESULTS: With endosaccular GDC treatment, 73.3% of the population experienced excellent to good recoveries (Glasgow Outcome Scale scores of 4 or 5), with a 13.3% procedure-related morbidity rate and a 6.7% procedure-related mortality rate. Two hemorrhaging episodes occurred after GDC treatment (annual bleeding rate, 2.5%; 2 hemorrhaging episodes/79.2 patient-yr). Symptoms related to aneurysmal mass effect were improved for 45.5% of the patients presenting with signs of neural compression. Among 23 patients with 24 aneurysms who were available for angiographic follow-up assessment, complete or nearly complete occlusion was observed for 17 aneurysms (71%; angiographic follow-up period, 24.3 +/- 19.6 mo, mean +/- standard deviation). A single total embolization served as definitive treatment for only 12.5% of the giant aneurysms and 31% of the very large aneurysms. CONCLUSION: Endosaccular GDC treatment of giant and very large aneurysms was accomplished with procedure-related morbidity and mortality rates comparable to those for open surgery performed by experts. However, because coil stability was unsatisfactory, we suggest that the GDC method should currently be reserved for individuals who are considered poor candidates for open surgery.

Chronic shunt-dependent hydrocephalus after early surgical and early endovascular treatment of ruptured intracranial aneurysms.

OBJECTIVE: The goal of this study was to document the influence of the treatment method (early surgery versus early endovascular treatment) on the development of chronic shunt-dependent hydrocephalus in a series of 242 patients treated within 7 days after aneurysmal subarachnoid hemorrhage (SAH). METHODS: The following parameters were prospectively recorded in a computerized database and retrospectively analyzed for association with chronic shunt-dependent hydrocephalus: 1) Hunt and Hess grade, 2) Fisher computed tomographic grade, 3) incidence of repeat SAH, 4) aneurysm location, and 5) treatment method (early surgery versus early endovascular treatment). RESULTS: Forty of 187 patients (21.4%) who survived the SAH and its neurological and/or medical sequelae underwent definitive shunting for treatment of chronic hydrocephalus. The rate of shunt dependency was positively correlated with a higher Hunt and Hess grade (P < 0.001), a higher Fisher computed tomographic grade (P = 0.003), the occurrence of intraventricular hemorrhage (P < 0.001), repeat SAH (P = 0.003), and aneurysms arising at the anterior communicating artery (P < 0.001). CONCLUSION: The results of the present study indicate that the treatment method used does not affect the risk of the later development of chronic shunt-dependent hydrocephalus (early surgery, 23.2% [29 of 125]; early endovascular treatment, 17.7% [11 of 62]; P = 0.45).

Evaluation of cerebral vasospasm after early surgical and endovascular treatment of ruptured intracranial aneurysms.

OBJECTIVE: To document the influence of the treatment modality (early surgery versus early endovascular treatment) on measures of cerebral vasospasm in a nonrandomized series of 156 patients treated within 72 hours of aneurysmal subarachnoid hemorrhage. METHODS: The following parameters were prospectively collected in a computerized data base and retrospectively analyzed for association with vasospasm-related ischemic infarctions: 1) Hunt and Hess (H&H) grade, 2) Fisher grade, 3) highest mean cerebral blood flow velocity (CBFVMAX) and maximum percent change in mean CBFV (%deltaCBFV) as recorded by transcranial Doppler ultrasound, 4) incidence of repeat subarachnoid hemorrhage, 5) incidence of delayed ischemic neurological deficits, 6) incidence of delayed ischemic infarctions, and 7) Glasgow Outcome Scale score. RESULTS: Forty-one patients (26.3%) suffered ischemic infarctions. The ischemic infarction rate was correlated with higher H&H grade (P = 0.002), higher Fisher grade (P = 0.05), higher CBFVMAX (P < 0.001) and %deltaCBFV (P = 0.01), occurrence of repeat subarachnoid hemorrhage, occurrence of delayed ischemic neurological deficits, and endovascular treatment (P = 0.02). CONCLUSION: The infarction rate was higher with endovascular treatment versus surgery (37.7 versus 21.6%), as a result of a skewed Fisher Grade 4 infarction pattern in the endovascular treatment group versus the surgery treatment group (66.7 versus 24.5%). We suspect that unremoved subarachnoid/intracerebral clots contributed to the higher infarction rate with endovascular treatment. When patients with Fisher Grade 4 and H&H Grade V were excluded from analysis, the difference in infarct incidence between the treatment groups no longer reached statistical significance (Fisher Grades 1-3, P = 0.49; H&H Grades I-IV, P = 0.96).

Endothelial lesions after temporary clipping. A comparative study.

The effect of temporary clipping on the arterial endothelium of rats was examined with scanning electron microscopy. The opening pressure of four Heifetz clips was modified by changing the springs. Four different clip forces (20, 35, 45, and 65 gm), four periods of clipping (10, 30, 60, and 180 minutes), and three vessel diameters (smaller than 1 mm, 1.1 to 1.3 mm, and 1.4 to 2 mm) were compared. Different grades of endothelial damage were observed. On gross examination the damage involved a detachment of endothelium and the adherence of platelets to the subendothelial tissue. The duration of clipping seemed to be of more importance than the clip force, whereas the vessel diameter had no recognizable influence.

Gross and microscopic histopathological findings in aneurysms of the human brain treated with Guglielmi detachable coils.

OBJECT: The histopathological characteristics of aneurysms obtained at autopsy or surgery 3 days to 54 months after being treated with Guglielmi detachable coils (GDCs) were assessed. METHODS: Seventeen aneurysms were obtained at autopsy and one was removed at surgery. Fourteen were examined histologically with the coils in situ. Naked coils embedded in an unorganized thrombus were found in those aneurysms that had been treated with coils within 1 week earlier. An incomplete replacement of the intraluminal blood clot by fibrous tissue and a partial membranous covering at the aneurysm orifice were observed in those aneurysms that had been treated with coils between 2 and 3 weeks prior to examination. One small aneurysm treated 6 weeks before harvesting showed formation of an endothelium-lined layer of connective tissue at the orifice. Collagen-rich vascularized tissue surrounding the coils was found in an aneurysm removed at surgery 54 months after coil implantation. Interestingly, six (50%) of 12 aneurysms (two small, three large, and one giant) that had been deemed 100% occluded on initial angiography showed tiny open spaces between the coils at the neck on gross examination. CONCLUSIONS: Endothelialization of the aneurysm orifice following placement of GDCs can occur; however, it appears to be the exception rather than the rule. In large aneurysms the process of intraaneurysm clot organization seems to be delayed and incomplete; tiny open spaces between the coils and an incomplete membranous covering in the region of the neck are frequently encountered. Further longitudinal studies are required to establish the spectrum of healing profiles that may direct our efforts in modifying the GDC system to produce a more stable long-term result.

Treatment of basilar artery bifurcation aneurysms by using Guglielmi detachable coils: a 6-year experience.

OBJECT: The authors retrospectively analyzed the results of their 6-year experience in the treatment of basilar artery (BA) bifurcation aneurysms by using Guglielmi detachable coils (GDCs). METHODS: This analysis involved 45 BA tip aneurysms in 16 men and 29 women who ranged in age from 23 to 78 years (mean 50 years). Seventy-five percent of the aneurysms had ruptured and 25% remained unruptured. Of the group whose aneurysms hemorrhaged, 14 patients were Hunt and Hess Grade I or II and 20 were Hunt and Hess Grades III to V; 32 patients were treated within 2 weeks of their subarachnoid hemorrhage (SAH). Initially, treatment with GDCs was limited to poor-grade high-risk patients who refused surgery or patients in whom surgery proved unsuccessful. Later in the study, good-grade patients with narrow-necked aneurysms were also treated using GDCs. The length of clinical follow up ranged from 1 to 72 months (average 27.4 months) in the 37 surviving patients. In 33 of the 45 aneurysms treated with coil placement, good to excellent results were achieved. There were 12 poor results (27%) including one in a patient from the non-SAH group who suffered a thrombotic complication due to an underlying vasculitis. Eight deaths were recorded in this group of 45 patients. One of these deaths was caused by a complication related to anesthesia, one by unknown causes, and six resulted from complications of the disease. One patient rebled on the 2nd day after the endovascular procedure. The mortality and permanent morbidity rates directly related to the intervention were 2.2% and 4.4%, respectively. Angiographic studies obtained immediately postintervention demonstrated 99 to 100% occlusion in 30 (67%) of the aneurysms; nine (20%) were more than 90% occluded; and six (13%) were less than 90% occluded by the GDCs. Follow-up angiograms were obtained in 31 patients between 2 and 72 months after coil placement. Nineteen (61%) of the follow-up angiograms revealed stable results (that is, no change from initial treatment). Twelve of the 31 showed coil compaction, but only eight of these lesions could accept additional coils. In large aneurysms recanalization was seen in 57%, and some of the larger lesions required as many as four embolizations (mean 1.7) to achieve optimal occlusion. When small-necked aneurysms were analyzed as a subset, a stable angiographic result was seen in 92%. CONCLUSIONS: Use of GDCs led to excellent clinical and angiographic results in the majority of patients with BA tip aneurysms included in this limited follow-up study. Rebleeding was encountered in one of the 34 previously ruptured BA aneurysms treated with GDCs, and no hemorrhages have been documented in the 11 unruptured aneurysms treated with GDCs in this series. Long-term follow-up studies are necessary before it is possible to compare adequately the treatment of aneurysms with coil placement to the gold standard of aneurysm clipping.

Pulmonary function and radiographic abnormalities related to neurological outcome after aneurysmal subarachnoid hemorrhage.

OBJECT: This observational study is based on a consecutive series of 207 patients with aneurysmal subarachnoid hemorrhage who were treated within 7 days of their most recent bleed. The purpose of the study was to evaluate the effect of respiratory failure on neurological outcome. METHODS: Pulmonary function was assessed by determination of parameters describing pulmonary oxygen transport and exchange, by using composite scores for quantification of lung injury (lung injury score [LIS]) and mechanical ventilator settings (PIF score). Pulmonary function was related to the Hunt and Hess (H & H) grade assigned to the patient at hospital admission (p < 0.001). The pattern and time course of lung injury differed significantly between patients with H & H Grade I or II, Grade III, and Grade IV or V. Hunt and Hess grade, Fisher computerized tomography grade, intracranial pressure, cerebral perfusion pressure, LIS, ratio of PaO2 to the fraction of inspired oxygen (FiO2), and the ratio of the alveolar-minus-arterial oxygen tension difference (AaDO2) to FiO2 were related to neurological outcome (p < 0.001). The LIS on the day of maximum lung injury remained an independent predictor of outcome (p = 0.01) in a stepwise logistic regression analysis. The probability of poor neurological outcome significantly increased with both decreasing cerebral perfusion pressure and increasing severity of lung injury. CONCLUSIONS: The overall mortality rate was 22.2% (46 of 207 patients). Subarachnoid hemorrhage and its neurological sequelae accounted for the principal mortality in this series. Medical (nonneurological and nontreatment-related) complications accounted for 37% of all deaths. Systemic inflammatory response syndrome with associated multiple organ dysfunction syndrome was the leading cause of death from medical complications. The authors conclude that respiratory failure is related to neurological outcome, although it is not commonly the primary cause of death from medical complications.

Endovascular management of patients with cerebral arteriovenous malformations.

The endovascular management of brain arteriovenous malformations (AVMs) is a part of the therapeutic AVM strategy. In selected cases, endovascular therapy may lead to a total and permanent cure, but in most cases it will be an adjunctive therapy to microsurgery or radiosurgery. Embolization of brain AVMs is still a technical challenge that requires experience and skill on the part of the physician and requires a further improvement of tools, but it has made brain AVMs curable.

Extensive facial vascular malformations and haemangiomas: a review of the literature and case reports.

We present 6 selected cases of extensive facial vascular anomalies extending to the skull base or actually involving it. These patients are compared with other cases in the literature. The spontaneous course of these vascular lesions is different and so variable treatment modalities are suggested depending on the age of the patient and the type of lesion. In young children, haemangiomas are common and spontaneous involution is characteristic. Conservative treatment in the sense of a wait-and-see approach is thereby favoured if there is no urgent indication such as involvement of essential structures, e.g. blockage of an orifice as demonstrated in one case or complications such as excessive bleeding. Vascular malformations most commonly appear in adults, there is no tendency to spontaneous involution and resection is usually necessary, especially in arteriovenous malformations. Nowadays, preoperative superselective embolization is recommended to minimize intraoperative blood loss. Superselective embolization is the treatment of choice in cases of a-v fistulae. Proximal ligation of the supplying arteries should be avoided because this may make embolization more difficult, and may be responsible for the common occurrence of rapid revascularization.

Radiosurgery in the treatment of cerebral AVMs.

Radiosurgery of AVM's is gaining in popularity and is advocated by many for the treatment of lesions less than 3 cm in diameter. During a 17 month period 33 patients with cerebral AVM's were treated with radiosurgery. All regions of the brain were represented in the series including brain stem. A mean follow-up of 10.8 months revealed a 6% rebleed rate and a 9% total complication rate. Multimodality therapy including embolization and surgery is recommended for the treatment of AVM's and radiosurgery is seen as an important adjunctive treatment option.

Evaluation of big endothelin-1 concentrations in serum and ventricular cerebrospinal fluid after early surgical compared with nonsurgical management of ruptured intracranial aneurysms.

OBJECT: Whereas the removal of subarachnoid blood is possible during early-stage aneurysm surgery, this cannot be achieved in aneurysms treated by endovascular means. The levels of potential spasmogens in the cerebrospinal fluid (CSF) in patients receiving endovascular treatment might therefore be higher, with the potential for more severe post-subarachnoid hemorrhage (SAH) vasospasm. METHODS: Serum and CSF concentrations of big endothelin (ET)-1 were serially measured in patients with SAH receiving one of the following treatments: 1) early (within 72 hours of SAH) aneurysm surgical treatment (15 patients), 2) early endovascular treatment (17 patients), or 3) no intervention in the acute phase (12 patients). In patients suffering delayed infarctions higher levels of big ET-1 CSF were demonstrated than in those without infarctions (p = 0.01). In patients in whom surgery was performed in the acute phase lower big ET-1 CSF concentrations were demonstrated than in those who received embolization treatment or no treatment (p = 0.02). Subgroup analysis demonstrated that in patients receiving early endovascular treatment, higher big ET-1 CSF concentrations were revealed than in those undergoing early aneurysm surgery; this was true for patients with (microsurgerytreated, 1.84 +/- 0.83 pg/ml; and embolization-treated 2.19 +/- 0.54 pg/ml) and without (microsurgery-treated 1.76 +/- 0.61 pg/ml; and embolization-treated 2.01 +/- 0.48 pg/ml) delayed infarctions. CONCLUSIONS: Among patients with SAH who received treatment during the acute phase, those undergoing early aneurysm surgery were shown to have lower big ET-1 CSF levels than those receiving embolization and no treatment (that is, the nonsurgical treatment groups). The clinical significance of this finding remains to be established in future clinical trials, because in the present study the trend toward lower levels of big ET-1 CSF in the microsurgically treated group was not paralleled by a lower delayed stroke rate or an improvement in neurological outcome.

[Glomus caroticum chemodectoma. Review on current diagnosis and therapy]. / Glomus caroticum--Chemodectom. Ubersicht über die aktuelle Diagnostik und Therapie.

Carotid body tumors are rare neoplasms arising from the small chemoreceptor organ in the adventitia of the common carotid bifurcation. Patients with carotid body tumours usually present with a gradually enlarging non-tender anterolateral neck mass. Differential diagnosis includes metastatic lymph nodes, carotid artery aneurysm, salivary gland tumour, branchial cleft cyst, and neurogenic or thyroid tumours. When such a lesion is suspected, a non-invasive Doppler colour flow ultrasonography enables the clinician to arrive at a definite diagnosis. Subsequent arteriography is mandatory, because the finding of an intensely blushing hypervascular mass spreading into the carotid bifurcation further supports the diagnosis and provides accurate preoperative information concerning arterial blood supply. Computed tomography scanning is appropriate to delineate the relation of the tumour to adherent structures, while magnetic resonance tomography demonstrates the relation of the tumour to the adjacent internal jugular vein and the carotid artery. Selective embolization should be performed for safe surgical removal with less bleeding. Early surgery is the treatment of choice and is recommended in order to minimize major risks. Subadventitial resection is the most established technique. Radical resection prevents local recurrence and has the best long-term results. Removal of the internal or common carotid arteries can become mandatory in selected cases of extensive disease. Surgical treatment by an experienced team is associated with considerably low mortality and morbidity.

Visual worsening after incomplete coiling of a small asymptomatic aneurysm: case report and review of the literature.

OBJECTIVE: Complications with increased mass effect on surrounding structures have as yet only been noted after coiling of large, giant, and thrombosed aneurysms. We describe a case of optic chiasm compression after incomplete coil embolization of a small ICA aneurysm and discuss the potential mechanisms causing this phenomenon. CASE REPORT: A 57-year-old male presented with an incidental, 7-mm diameter, C2 segment, ICA aneurysm. Endovascular intervention with platinum coils resulted in 80% obliteration. Approximately three weeks later the patient developed visual changes which progressed over 10 days to a homonymous hemianopsia with a central scotoma. A pterional craniotomy was performed to decompress and to definitively clip the aneurysm. Histological evaluation of the aneurysm showed sinusoidal vessels, filled with proliferated endothelial cells and being encapsulated by fibrous tissue, suspicious for exposure to systemic blood pressure. CONCLUSION: Even small aneurysms undergoing incomplete coil embolization may affect surrounding, eloquent neural structures due to unexpected tissue formation in the aneurysm.

Accidental transtumoral microparticle embolization of eloquent brain areas in a case of large temporofrontal meningioma.

SUMMARY: We report a case of transtumoral diapedesis of microparticles during preoperative embolization of a large symptomatic temporofrontal meningioma, resulting in severe neurological deficit. In retrospective analysis of angiographic images, the pattern of supply to the tumour was found to be predictive for wide anastomotic channels connecting the dural and pial supply, thereby increasing the risk of the procedure. Recognising this pattern can prevent this rare cause of complication in a still controversial procedure.