Category: Vascular

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A 3-tier classification of cerebral arteriovenous malformations

J Neurosurg 114:842–849, 2011.DOI: 10.3171/2010.8.JNS10663

The authors propose a 3-tier classification for cerebral arteriovenous malformations (AVMs). The classification is based on the original 5-tier Spetzler-Martin grading system, and reflects the treatment paradigm for these lesions. The implications of this modification in the literature are explored.

Methods. Class A combines Grades I and II AVMs, Class B are Grade III AVMs, and Class C combines Grades IV and V AVMs. Recommended management is surgery for Class A AVMs, multimodality treatment for Class B, and observation for Class C, with exceptions to the latter including recurrent hemorrhages and progressive neurological deficits. To evaluate whether combining grades is warranted from the perspective of surgical outcomes, the 3-tier system was applied to 1476 patients from 7 surgical series in which results were stratified according to Spetzler- Martin grades.

Results. Pairwise comparisons of individual Spetzler-Martin grades in the series analyzed showed the fewest significant differences (p < 0.05) in outcomes between Grades I and II AVMs and between Grades IV and V AVMs. In the pooled data analysis, significant differences in outcomes were found between all grades except IV and V (p = 0.38), and the lowest relative risks were found between Grades I and II (1.066) and between Grades IV and V (1.095). Using the pooled data, the predictive accuracies for surgical outcomes of the 5-tier and 3-tier systems were equivalent (receiver operating characteristic curve area 0.711 and 0.713, respectively).

Conclusions. Combining Grades I and II AVMs and combining Grades IV and V AVMs is justified in part because the differences in surgical results between these respective pairs are small. The proposed 3-tier classification of AVMs offers simplification of the Spetzler-Martin system, provides a guide to treatment, and is predictive of outcome. The revised classification not only simplifies treatment recommendations; by placing patients into 3 as opposed to 5 groups, statistical power is markedly increased for series comparisons.

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Endovascular Therapy of Very Small Aneurysms of the Anterior Communicating Artery: Five-fold Increased Incidence of Rupture

Neurosurgery 68:731–737, 2011 DOI: 10.1227/NEU.0b013e3182077373

Intraprocedural rupture is a dangerous complication of endovascular treatment. Small ruptured anterior communicating artery (ACoA) aneurysms and microaneurysms present a challenge for both surgical and endovascular therapies to achieve obliteration. An understanding of the complication rates of treating ruptured ACoA microaneurysms may help guide therapeutic options.

OBJECTIVE: To report the largest cohort of ACoA microaneurysms treated with endovascular therapy over the course of the past 10 years.

METHODS: We performed a retrospective review of 347 ACoA aneurysms treated in 347 patients at Cleveland Clinic and Emory University over a 10-year period. Patient demographics, aneurysmal rupture, size, use of balloon remodeling, patient outcomes, intraprocedural rupture, and rerupture were reviewed.

RESULTS: Rupture rates were examined by size for all patients and subgroups and dichotomized to evaluate for size ranges associated with increased rupture rates. The highest risk of rupture was noted in aneurysms less than 4 mm. Of 347 aneurysms, 74 (21%) were less than 4 mm. The intraprocedural rupture rate was 5% (18/347) for ACoA aneurysms of any size. There was an intraprocedural rupture rate of 2.9% (8/273) among ACoA aneurysms greater than 4 mm compared with 13.5% (10/74) in less than 4-mm aneurysms. Procedural rupture was a statistically significant predictor of modified Rankin score after adjusting for Hunt and Hess grades (HH).

CONCLUSION: ACoA aneurysms less than 4 mm have a 5-fold higher incidence of intraprocedural rerupture during coil embolization. Outcome is negatively affected by intraprocedural rerupture after adjusting for HH grade.

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Advances in the Treatment and Outcome of Brainstem Cavernous Malformation Surgery: A Single-Center Case Series of 300 Surgically Treated Patients

Neurosurgery 68:403–415, 2011 DOI: 10.1227/NEU.0b013e3181ff9cde

Brainstem cavernous malformations (BSCMs) are relatively uncommon, low-flow vascular lesions. Because of their relative rarity, relatively little data on their natural history and on the efficacy and durability of their treatment.

OBJECTIVE: To evaluate the long-term durability of surgical treatment of BSCMs and to document patient outcomes and clinical complications.

METHODS: The charts of all patients undergoing surgical treatment of BSCM between 1985 and 2009 were reviewed retrospectively. The study population consisted of 300 patients who had surgery for BSCM. Forty patients were under 19 years of age at surgery; pediatric BSCMs have been reported separately. Patient demographics, lesion characteristics, surgical approaches, and patient outcomes were examined.

RESULTS: The study population consisted of 260 adult patients with a female-to-male ratio of 1.5 and mean age of 41.8 years. Of the 260 patients, 252 presented with a clinical or radiographic history of hemorrhage. The mean follow-up in 240 patients was 51 months. The mean Glasgow Outcome Scale on admission, at discharge, and at last follow-up was 4.4, 4.2, and 4.6. Postoperatively, 137 patients (53%) developed new or worsening neurological symptoms. Permanent new deficits remained in 93 patients 3(36%). There were perioperative complications in 74 patients (28%); tracheostomy, feeding tube placement, and cerebrospinal fluid leakage were most common. Eighteen patients (6.9%) experienced 20 rehemorrhages. Twelve patients required reoperation for residual/recurrent BSCM. The overall annual risk of postoperative rehemorrhage was 2%/patient.

CONCLUSION: Although BSCM surgery has significant associated risks, including perioperative complications, new neurological deficits, and death, most patients have favorable outcomes. Overall, surgery markedly improved the risk of rehemorrhage and related symptoms and should be considered in patients with accessible lesions.

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Risk of Hemorrhage in Patients With Untreated Spetzler-Martin Grade IV and V Arteriovenous Malformations: A Long-term Follow-up Study in 63 Patients

Neurosurgery 68:372–378, 2011 DOI: 10.1227/NEU.0b013e3181ffe931

Treatment of Spetzler-Martin Grade IV and V brain arteriovenous malformations (ie, high-grade AVMs) carries a high risk of morbidity and even mortality. However, little is known about the behavior of these lesions if left untreated.

OBJECTIVE: To investigate the natural history of patients with high-grade AVMs.

METHODS: Patients with untreated high-grade AVMs admitted to our center between 1952 and 2005 were followed from admission until death, AVM rupture, or initiation of treatment. Rates of rupture and various risk factors were analyzed using Kaplan-Meier life table analyses and Cox proportional hazards models. Functional outcome was assessed 1 year after possible AVM rupture using the Glasgow Outcome Scale.

RESULTS: Sixty-three patients with a mean follow-up time of 11.0 years (range, 1 month to 39.6 years) were identified. Twenty-three patients (37%) experienced a subsequent rupture. The average annual rate of rupture was 3.3%. In patients with hemorrhagic presentation, the annual rate was 6.0%, compared to 1.1% in patients with unruptured AVMs (P = .001, log-rank test; hazard ratio, 5.09 [1.40-18.5, 95% CI]; P = .013, multivariate Cox regression model). One year after the first subsequent rupture, 6 patients (26%) had died, and 9 (39%) had moderate or severe disability.

CONCLUSION: Untreated high grade AVMs presenting with hemorrhage have a significant risk of subsequent rupture, and their rupture carries a higher risk of case fatality and permanent morbidity than AVMs in general. The risks associated with their treatment should be appraised in light of perilous natural history.

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Aneurysm Volume-to-Ostium Area Ratio: A Parameter Useful for Discriminating the Rupture Status of Intracranial Aneurysms

Neurosurgery 68:310–318, 2011 DOI: 10.1227/NEU.0b013e3182010ed0

Slow or stagnant flow is a hemodynamic feature that has been linked to the risk of aneurysm rupture.

OBJECTIVE: To assess the potential value of the ratio of the volume of an aneurysm to the area of its ostium (VOR) as an indicator of intra-aneurysmal slow flow and, thus, in turn, the risk of rupture.

METHODS: Using a sample defined from internal databases, a retrospective analysis of aneurysm size, aspect ratio (AR), and VOR was performed on a series of 155 consecutive aneurysms having undergone 3-dimensional digital subtraction angiography as a part of their evaluation. Measurements were obtained from 3-dimensional digital subtraction angiography studies using commercial software. Aneurysm size, AR, and VOR were correlated with rupture status (ruptured or unruptured). A multiple logistic regression model that best correlated with rupture status was generated to evaluate which of these parameters was the most useful to discriminate rupture status. This model was validated using an independent database of 62 consecutive aneurysms acquired outside the retrospective study interval.

RESULTS: VOR showed better discrimination for rupture status than did size and AR. The best logistic regression model, which included VOR rather than size or AR, determined rupture status correctly in 80.6% of subjects. The reproducibility calculating AR and VOR was excellent.

CONCLUSION: Determination of VOR was easily done and reproducible using widely available commercial equipment. It may be a more robust parameter to discriminate rupture status than AR.

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Microsurgical treatment of temporal lobe cavernomas

Acta Neurochir (2011) 153:261–270. DOI 10.1007/s00701-010-0812-5

Cavernomas of the temporal lobe occur in 10– 20% of patients with cerebral cavernomas. They frequently cause epileptic seizures, some of which tend to become refractory to medical therapy. Surgical removal of safely achievable symptomatic lesions has been frequently consistent with good long-term outcome. In the present study, a postoperative outcome is assessed.

Methods Of our 360 consecutive patients with cerebral cavernomas, 53 (15%) had a single cavernoma in the temporal lobe. Forty-nine patients were treated surgically and were included in the study. All data were analyzed retrospectively. The cavernomas were allocated into three groups based on the temporal lobe site: medial, anterolateral, and posterolateral. To collect follow-up data, all available patients were interviewed by phone. Seizure outcome was assessed using the Engel classification and general outcome using the Glasgow Outcome Scale (GOS).

Results Patients’ median age at presentation was 37 (range, 7–64) years, with a female/male ratio of 2.5:1. Epileptic seizures occurred in 40 patients (82%). Median duration of seizures preoperatively was 3 (range, 0.1–23) years. In addition, four patients (10%) had memory disorder. Three patients without history of seizures (6%) complained of headache and two (4%) had memory problems. Three patients (6%) had an incidental cavernoma. Hemorrhage occurred in nine patients (18%) preoperatively. Median postoperative follow-up time was 6 (range, 0.2–26) years. Favorable seizure outcome (Engel class I and II) was registered in 35 patients (90%). Ten patients (25%) who had only a single seizure before surgery were seizure free during postoperative follow-up. Good general outcome (GOS, 4.5) was detected in 46 patients (96%). Two patients (4%) developed a new mild memory deficit after surgery, and in two patients existing memory deficits worsened.

Conclusions Microsurgical removal of temporal lobe cavernomas is a safe and effective method to improve seizure outcome in patients with medically intractable epilepsy and to prevent deterioration caused by hemorrhage.

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Ruptured anterior paraclinoid aneurysms

Neurosurg Rev (2011) 34:49–55. DOI 10.1007/s10143-010-0272-7

The purpose of this study was to evaluate cases of subarachnoid hemorrhage (SAH) from ruptured anterior (dorsal) paraclinoid aneurysms. Anterior paraclinoid aneurysms are defined as aneurysms arising from the anterolateral wall of the proximal internal carotid artery without any relationship to an arterial branch.

Between 1991 and 2008, a total of 159 patients with 169 paraclinoid aneurysms were treated at the Shinshu University Hospital and its affiliated hospitals. A retrospective analysis was carried out using charts, operation records, operation videos, and neuroimagings. Twenty six patients had anterior paraclinoid aneurysm. Six patients presented with SAH. Three aneurysms were saccular and the others were blister-like aneurysms based on operative findings. Neck laceration or premature rupture frequently happened during the clipping surgery even though the aneurysm was saccular type.

The treatment of a ruptured anterior paraclinoid aneurysm is quite difficult. Trapping and bypass would be recommended for such fragile aneurysms.

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Chronic subdural hematoma in the elderly: not a benign disease

J Neurosurg 114:72–76, 2011. (DOI: 10.3171/2010.8.JNS10298)

Chronic subdural hematoma (CSDH) is perceived to be a “benign,” easily treated condition in the elderly, but reported follow-up periods are brief, usually limited to acute hospitalization.

Methods. The authors conducted a retrospective review of data obtained in a prospectively identified consecutive series of adult patients admitted to their institution between September 2000 and February 2008 and in whom there was a CT diagnosis of CSDH. Survival data were compared to life-table data.

Results. Of the 209 cases analyzed, 63% were men and the mean age was 80.6 years (range 65–96 years). Primary surgical interventions performed were bur holes in 21 patients, twist-drill closed-system drainage in 44, and craniotomies in 72. An additional 72 patients were simply observed. Reoperations were recorded in 5 patients—4 who had previously undergone twist-drill drainage and 1 who had previously undergone a bur hole procedure (p = 0.41, chi-square analysis). Thirty-five patients (16.7%) died in hospital, 130 were discharged to rehabilitation or a skilled care facility, and 44 returned home. The follow-up period extended to a maximum of 8.3 years (median 1.45 years). Six-month and 1-year mortality rates were 26.3% and 32%, respectively. In the multivariate analysis (step-wise logistic regression), the sole factor that predicted in-hospital death was neurological status on admission (OR 2.1, p = 0.02, for each step). Following discharge, the median survival in the remaining cohort was 4.4 years. In the Cox proportional hazards model, only age (hazard ratio [HR] 1.06/year, p = 0.02) and discharge to home (HR 0.24, p = 0.01) were related to survival, whereas the type of intervention, whether surgery was performed, size of subdural hematoma, amount of shift, bilateral subdural hematomas, and anticoagulant agent use did not affect the long- or short-term mortality rate. Comparison of postdischarge survival and anticipated actuarial survival demonstrated a markedly increased mortality rate in the CSDH group (median survival 4.4 vs 6 years, respectively; HR 1.94, p = 0.0002, log-rank test). This excess mortality rate was also observed at 6 months postdischarge with evidence of normalization only at 1 year.

Conclusions. In this first report of the long-term outcome of elderly patients with CSDH the authors observed persistent excess mortality up to 1 year beyond diagnosis. This belies the notion that CSDH is a benign disease and indicates it is a marker of other underlying chronic diseases similar to hip fracture

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Ruptured anterior paraclinoid aneurysms

Neurosurg Rev (2011) 34:49–55. DOI 10.1007/s10143-010-0272-7

The purpose of this study was to evaluate cases of subarachnoid hemorrhage (SAH) from ruptured anterior (dorsal) paraclinoid aneurysms.

Anterior paraclinoid aneurysms are defined as aneurysms arising from the anterolateral wall of the proximal internal carotid artery without any relationship to an arterial branch.

Methods. Between 1991 and 2008, a total of 159 patients with 169 paraclinoid aneurysms were treated at the Shinshu University Hospital and its affiliated hospitals. A retrospective analysis was carried out using charts, operation records, operation videos, and neuroimagings.

Results. Twenty six patients had anterior paraclinoid aneurysm. Six patients presented with SAH. Three aneurysms were saccular and the others were blister-like aneurysms based on operative findings. Neck laceration or premature rupture frequently happened during the clipping surgery even though the aneurysm was saccular type.

Conclusions. The treatment of a ruptured anterior paraclinoid aneurysm is quite difficult. Trapping and bypass would be recommended for such fragile aneurysms.

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Microsurgery for Previously Coiled Aneurysms: Experience With 81 Patients

Neurosurgery 68:140–154, 2011 DOI: 10.1227/NEU.0b013e3181fd860e

Residual and recurrent intracranial aneurysms after endovascular treatment with Guglielmi detachable coils may necessitate a microsurgical occlusion.

OBJECTIVE: To analyze the microsurgical technique and describe how the location, morphology, and appearance of the coiled aneurysm affect the technique.

METHODS: We retrospectively analyzed 81 patients with 82 previously coiled aneurysms treated microsurgically at 2 Finnish neurosurgical university hospitals in Helsinki and Kuopio between July 1995 and August 2009. Seven videos were selected to demonstrate the microsurgical strategy in various locations.

RESULTS: Fifty-eight aneurysms (71%) were located at anterior circulation and 24 (29%) at posterior circulation. Fifteen patients were operated on within the first month (early surgery) after coiling, whereas 66 were treated later (late surgery). Complete or partial removal of coils during surgery may facilitate clipping, but is significantly (P, .001) more difficult to accomplish in late surgery. Removal of coils may also increase the chance of poor outcome. Chance of poor outcome also increased with intraoperative aneurysm rupture, size of the aneurysm, and posterior circulation location. Good clinical outcome (same or better clinical condition 3 months after surgery) was achieved in 71 patients (88%). After microsurgery, 4 patients were severely disabled and 6 patients died, 3 of them because of poor clinical condition.

CONCLUSION: Complete microsurgical occlusion of the residual aneurysm is possible. However, in large or giant aneurysms direct microsurgery is a challenging high-risk procedure, and we recommend that these patients be referred to a dedicated neurovascular center to minimize surgical complications. Even in experienced hands, use of different bypass procedures may be the best option for demanding growing lesions, especially those in the posterior circulation.

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The Association Between Weather and Spontaneous Subarachnoid Hemorrhage: An Analysis of 155 US Hospitals

Neurosurgery 68:132–139, 2011 DOI: 10.1227/NEU.0b013e3181fe23a1

A seasonal and meteorological influence on the incidence of spontaneous subarachnoid hemorrhage (SAH) has been suggested, but a consensus in the literature has yet to emerge.

OBJECTIVE: This study examines the impact of weather patterns on the incidence of SAH using a geographically broad analysis of hospital admissions and represents the largest study of the topic to date.

METHODS: We retrospectively analyzed SAH admissions to 155 US hospitals during the calendar years 2004 to 2008 (N = 7758). Daily weather readings for temperature, pressure, and humidity were obtained for the same period from National Oceanic and Atmospheric Administration weather stations located near each hospital. The daily values of each weather variable were associated with the daily volume of SAH admissions using a combination of correlation and time-series analyses.

RESULTS: No seasonal trends were observed in the monthly volume of SAH admissions during the study period. No significant correlation was detected between the daily SAH admission volume and the day’s weather, the previous day’s weather, or the 24-hour weather change.

CONCLUSION: This study represents the most comprehensive investigation of the association between weather and spontaneous SAH to date. The results suggest that neither season nor weather significantly influences the incidence of SAH.

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A Novel Aneurysm Clip Design for Atheromatous, Thrombotic, or Previously Coiled Lesions

Neurosurgery 67[ONS Suppl 2]:ons333–ons341, 2010 DOI: 10.1227/NEU.0b013e3181f7451b

Large and giant lesions often have thicker, atheromatous walls as well as intra-aneurysmal thrombus that combine to prevent traditional clips from closing properly in some cases.

OBJECTIVE: To report the development and use of a novel clip design specifically tailored to treat atheromatous, thrombotic, or previously coiled aneurysms.

METHODS: We retrospectively reviewed the records of 6 patients with complex aneurysms not amenable to simple neck clipping and not considered appropriate for endovascular therapy who were treated using a novel ‘‘compression’’ clip design. We describe the development and use of a novel aneurysm clip design with blades that are not opposed at rest to allow direct clipping of atheromatous, thrombotic, and previously coiled aneurysms.

RESULTS: Four patients had recurrent, previously coiled aneurysms; one of these also had a large thrombotic component. Two patients had complex lesions with heavy atheroma involving a portion of their aneurysms. There were no complications related to the use of the clip, and all patients did well without neurological complications. In every case, the clip allowed straightforward obliteration of the aneurysm without the need for temporary vascular occlusion, aneurysmorrhaphy, or removal of an intra-aneurysmal coil mass. All patients underwent intraoperative angiography to confirm obliteration of the aneurysm with preservation of the normal vasculature.

CONCLUSION: Atheromatous, thrombotic, and previously coiled aneurysms may not be treatable with simple neck clipping and may not be curable with endovascular therapy. For such cases, we designed a novel ‘‘compression’’ clip that has been used safely and successfully in our experience with good short-term follow-up.

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Cavernous Malformations of the Brainstem Presenting in Childhood: Surgical Experience in 40 Patients

Neurosurgery 67:1589–1599, 2010 DOI: 10.1227/NEU.0b013e3181f8d1b2

Brainstem cavernous malformations (BSCMs) are believed to compose 9% to 35% of all cerebral cavernous malformations, but these lesions have been reported in children in very limited numbers.

OBJECTIVE: To review surgical outcomes of pediatric patients with BSCMs treated at 1 institution.

METHODS: We retrospectively analyzed the course of 40 pediatric patients (19 males, 21 females; age range, 10 months to 18.9 years; mean, 12.3 years) who underwent surgery between 1984 and 2009. Age, sex, presenting symptoms, location of lesion, surgical approach, new postoperative deficits, Glasgow Outcome Scale score, recurrences, and resolution of baseline symptoms were recorded.

RESULTS: Thirty-nine patients experienced hemorrhage before surgery. Lesion locations included the pons (n = 22), midbrain (n = 4), midbrain and thalamus (n = 4), pontomesencephalic junction (n = 3), medulla (n = 3), pontomedullary junction (n = 3), and cervicomedullary junction (n = 1). Mean lesion size was 2.3 cm. Mean length of hospital stay was 10.7 days. The average clinical follow-up was 31.9 months in 36 patients with follow-up after discharge. At last follow-up, 5 patients had experienced symptoms and/ or imaging consistent with rehemorrhage, either from a residual that enlarged or true recurrence (5.25% annual rebleed risk per patient after surgery); 2 required reoperation for further resection of cavernoma. Mean Glasgow Outcome Scale score was 4.2 on admission, 4.05 at discharge, and 4.5 at latest follow-up. Preoperative symptoms and deficits improved in 16 patients (40%). New neurological deficits developed in 19 patients (48%) and resolved in 9, leaving 10 patients (25%) with new permanent deficit.

CONCLUSION: Compared with adults, pediatric patients with BCSMs tend to have larger lesions and higher rates of recurrence (regrowth of residual lesion). Given the greater life expectancy of children, surgical treatment seems warranted in those with surgically accessible lesions that have bled. Outcomes were similar to those in our adult series of patients with BSCMs.

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Partially thrombosed intracranial aneurysms: symptoms, evolution, and therapeutic management

Acta Neurochir (2010) 152:2133–2142. DOI 10.1007/s00701-010-0772-9

Partially thrombosed intracranial aneurysms (PTIAs) are different from saccular or nonthrombosed giant or large aneurysms, as they are characterized by multiple intramural thrombotic phenomena related to recurrent vessel wall dissections.

Methods We retrospectively reviewed clinical and radiological files of 23 consecutive patients with PTIAs (mean age 49.3 years). Twenty-two lesions were studied by magnetic resonance imaging (MRI). Patients were managed by endovascular treatments, medically with steroids, or conservatively.

Results Thirteen patients presented with progressive neurological symptoms. Subarachnoid hemorrhage was suspected but not proven in three. At MRI, 90.9% of PTIAs caused mass effect; perilesional T2 hypersignal compatible with edema was evident in 13.6%. Aneurysmal wall enhancement was detectable in 63.2% of the PTIAs and considered a marker of inflammatory processes. Parent artery occlusion was performed in seven patients with clinical improvement in six. Selective coiling was proposed in three patients (one improved, one remained stable, and one experienced symptoms progression). Three patients were treated with steroids and improved. Ten patients were managed conservatively: eight because spontaneous thrombosis of the lesion had been diagnosed and two because of clinical and radiological stability.

Conclusions The natural history of PTIAs is different from other aneurysms. They most commonly present with progressive neurological symptoms due to mass effect. MRI properly diagnoses PTIAs and allows precise followup, more accurately than angiography because it detects prominent “abluminal” features indicating inflammation and neovascularization. Spontaneous thrombosis is part of the natural history of PTIAs and it should be taken in consideration when discussing the therapeutic management.

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Visualization of the Anterior Cerebral Artery Complex With a Continuously Variable-View Rigid Endoscope: New Options in Aneurysm Surgery

Neurosurgery 67[ONS Suppl 2]:ons321–ons324, 2010 DOI: 10.1227/NEU.0b013e3181f74548.

Neuroendoscopy is increasingly used as an adjunctive tool in intracranial aneurysm surgery.

OBJECTIVE: To assess the versatility of a prototype continuously variable-view rigid endoscope in visualizing the anterior cerebral artery complex.

METHODS: In 5 formaldehyde-fixed, arterially injected specimens, a standard frontolateral approach was used on both sides. After meticulous microsurgical dissection using this approach, the prototype of a multivariable rigid endoscope (EndoCAMeleon; Karl Storz GmbH & Co, Tuttlingen, Germany) was inserted. It is a rigid endoscope that is capable of changing its angle of view while remaining stationary and shape invariant. We inspected the anterior cerebral artery complex, using and testing the capabilities of the device.

RESULTS: The continuously variable viewing mechanism enables the surgeon to adjust the field of view continuously and to optimize the visualization of the neurovascular structures. Because of the rigid tip combined with the continuously variable viewing mechanism, the need to move the endoscope within the surgical field was minimal. The field of view changes, but the tip itself hardly moves. The EndoCAMeleon was able to enhance both the visibility of the anterior cerebral artery complex and the accessibility of the A1 and A2 arterial walls to a range of approximately 270 degrees.

CONCLUSION: The EndoCAMeleon enhances the visibility of the anterior cerebral artery complex and facilitates endoscope-assisted inspection, planning of clip application, and clip control.

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Clinical presentation and treatment of distal posterior inferior cerebellar artery aneurysms

Neurosurg Rev. DOI 10.1007/s10143-010-0296-z

Aneurysms located at the distal portion of the posterior inferior cerebellar artery (PICA) are rare, and their clinical features are not fully understood. We report the clinical features and management of 30 distal PICA aneurysms in 28 patients treated during the past decade at Kagoshima University Hospital and affiliated hospitals.

Our series includes 20 women and eight men. Of their 30 aneurysms, 24 were ruptured, and six were unruptured; there were 27 saccular and two fusiform aneurysms; one was dissecting. Their location was at the anterior-medullary (n=4), lateral-medullary (n=9), tonsillomedullary (n=7), telovelotonsillar (n=6), and cortical (n =4) segment of the PICA. In 18 patients, angiographic features suggested hemodynamic stress including an absent contralateral PICA or ipsilateral anterior inferior cerebellar artery, termination of the vertebral artery (VA) at the PICA, and hyperplasia or occlusion of the contralateral VA.

As three patients died before surgery, 27 aneurysms in 25 patients were surgically treated. Of these, 6 were unruptured aneurysms; 20 were clipped via midline or lateral suboccipital craniotomy, and 5 were embolized with Guglielmi coils; in one, the PICA flow was reconstructed by OA-PICA anastomosis, and in the other one, the PICA was resected.

Of the 25 surgically treated patients, 22 (88%) had good outcomes. The predominant contributor to the development of distal PICA aneurysms is thought to be increased hemodynamic stress attributable to anomalies in the PICA and related posterior circulation. Both direct clipping and coil embolization yielded favorable outcomes in our series. However, considering the difficulties that may be encountered at direct clipping in the acute stage and the availability of advanced techniques and instrumentation, aneurysmal coiling is now the first option to address these aneurysms.

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Surgical Treatment of Spinal Dural Arteriovenous Fistulae: A Consecutive Series of 154 Patients

Neurosurgery 67:1350–1358, 2010 DOI: 10.1227/NEU.0b013e3181ef2821

Embolization of spinal dural arteriovenous fistulae (SDVAFs) has emerged as an alternative to surgery. However, surgical disconnection is a simple and effective procedure.

OBJECTIVE: To review results and complications of surgical treatment of 154 consecutive SDAVFs.

METHODS: The records of 154 consecutive patients with SDAVFs were retrospectively reviewed.

RESULTS: There were 120 males and 34 females (male/female ratio 3.5:1, mean age 63.6 years). The SDAVFs were located at the thoracic level in 92 patients and at the lumbar and sacral spine levels in 45 and 15 patients, respectively. The most common presenting symptoms were motor dysfunction (65 patients), sensory loss (31 patients), and paresthesias without sensory loss (13 patients). The mean interval from symptom onset to definitive diagnosis was 24.7 months (median 12 months). Surgery resulted in complete exclusion of the fistula at first attempt in 146 patients (95%). There were no deaths or major neurological complications related to the surgery. Six percent of patients experienced subjective or objective worsening of preoperative symptoms and signs by the time of discharge that persisted at follow-up. Other surgical complications consisted of wound infection in 2 patients and deep venous thrombosis in 3. Eight patients were lost to follow-up; 141 patients (96.6%) experienced improvement (120 patients, 82.2%) or stability (21 patients, 14.4%) of motor function at last follow-up compared with their preoperative status. Other symptoms such as numbness, sphincter dysfunction, and dysesthesias/neuropathic pain improved in 51.5%, 45%, and 32.6%, respectively.

CONCLUSION: Surgical obliteration of SDAVFs is safe and very effective. Prognosis of motor function is favorable after surgical treatment.

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Treatment of Giant Cerebral Arteriovenous Malformation: Hypofractionated Stereotactic Radiation as the First Stage

Neurosurgery 67:1253–1259, 2010 DOI: 10.1227/NEU.0b013e3181efbaef

Treatment of giant cerebral arteriovenous malformations (AVMs) remains a challenge.

OBJECTIVE: To propose hypofractionated stereotactic radiotherapy (HSRT) as a part of staged treatment, and evaluate its effect by analyzing AVM volume changes.

METHODS: From 2001 to 2007, 20 AVMs larger than 5 cm were treated by HSRT and followed up using magnetic resonance imaging. Patients’ median age was 34 years (8–61 years). Eleven patients presented with hemorrhage and 9 with seizure. Ten patients had previous embolization and radiosurgery had failed in 4. Thirteen AVMs (65%) were classified as Spetzler-Martin grade V and 7 as grade IV. Median pretreatment volume was 46.84 cm3 (12.51-155.38 cm3). Dose was 25 to 30 Gy in 5 to 6 daily fractions. Median follow-up was 32 months.

RESULTS: Median AVM volume decreased to 13.51 cm3 (range, 0.55-147.14 cm3). Residual volume varied from 1.5% to 98%. Volume decreased 44% every year on average. We noted that 6-Gy fractions were more effective (P = .040); embolized AVM tended to respond less (P = .085). After HSRT, we reirradiated 4 AVMs, with 3 amenable to single dose and one with fractions. After HSRT, one patient had an ischemic stroke and one had increased seizure frequency. One AVM bled during follow-up (2.06%/year). No complete obliteration was confirmed.

CONCLUSION: HSRT can turn some giant AVMs manageable for single-dose radiosurgery. Six-Gray fractions were better than 5-Gy and routine embolization seemed unhelpful. There was no increase in bleeding risk with this approach. Future studies with longer follow-up are necessary to confirm our observation.

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Surgical Treatment of Giant Intracranial Arteriovenous Malformations

Neurosurgery 67:1359–1370, 2010 DOI: 10.1227/NEU.0b013e3181eda216

The treatment of giant arteriovenous malformations (AVMs) remains a challenge in the neurosurgical field. Microsurgery is one of the most effective ways for eliminating giant cerebral AVMs.

OBJECTIVE: To review surgical outcomes in treating the disease, and form conclusions regarding the indications for and outcomes of surgical treatment in giant intracranial AVMs.

METHODS: We studied 40 consecutive cases of giant AVMs treated in Beijing Tiantan Hospital between 2000 and 2008. The radiologic and clinical features were analyzed. The Spetzler-Martin grading system was used to classify the patients. All patients were surgically treated, and the final outcomes of the patients were gathered for analysis.

RESULTS: The major presenting symptoms were seizures, headaches, hemorrhage, and neurological deficits. The mean AVM diameter was 6.3 cm. According to the Spetzler- Martin grading system, 5 patients had grade III lesions, 21 had grade IV lesions, and 14 had grade V lesions. Out of the total 40 patients, 31 (77.5%) demonstrated excellent or good outcome. Complications included hemiparalysis, aphasia, hemianopia, cranial nerve dysfunction, and seizures. After follow-up, 27 of 30 (90%) surviving patients presented normal function or minimal symptoms.

CONCLUSION: Presurgical evaluation of every candidate and treatment choice is the determining factor in therapy for giant AVMs. For giant cerebral AVMs located superficially or not involving critical components, a good outcome can be expected through surgical resection. The obliteration and recurrence rates were satisfying, and the complication rate was acceptable.

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Capillary telangiectasias: clinical, radiographic, and histopathological features

J Neurosurg 113:709–714, 2010. DOI: 10.3171/2009.9.JNS09282

Brain capillary telangiectasias (BCTs) are small, clinically benign, angiographically occult lesions that are usually incidental findings. Large capillary telangiectasias have not been reported previously as most BCTs are very small. Symptomatic BCTs are also rare, with few reports in the literature. The authors review the clinical manifestations, imaging, and histopathological characteristics of BCTs to further elucidate the diagnostic and clinical features of these vascular malformations.

Methods. The authors completed a retrospective radiological review of all cases of BCTs in the neuroradiology database at the University of Utah involving patients treated between January 1993 and December 2007. The MR imaging scans were reviewed, and the BCT was measured in 2 dimensions. They arbitrarily chose > 1 cm to define a large BCT as a majority of these lesions were smaller than that. The medical chart and the electronic database were used to gather each patient’s clinical information.

Results. One hundred thirty patients were identified in the archived neuroradiology database of capillary telangiectasias. Cases involving 105 patients with definite capillary telangiectasias were reviewed, and from these, 7 patients were identified to have a large capillary telangiectasia measuring > 1 cm. Upon further review, 2 of these patients were identified as having symptoms likely related to their capillary telangiectasia. These 2 cases are reported in the article. No patients with smaller BCTs were found to have symptoms related to their lesion.

Conclusions. Brain capillary telangiectasias are small vascular malformations that rarely cause symptoms. They are often overlooked on imaging because of their clinically benign nature; however, they have been misdiagnosed as glial tumors in the past. Specific MR imaging sequences (T1-weighted postcontrast and gradient refocused echo) are valuable in aiding diagnosis, as histopathological diagnosis is often not possible. These cases highlight that BCTs can cause symptoms, a finding that may actually be related to the size of the lesion (28.6% of large BCTs in this series were symptomatic, whereas none of the small ones were).

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