Vascular – Page 27 – Neurosurgery Blog

08/09/201507/09/2015

Venous Drainage–Based Classification System for Carotid Cavernous Fistulae

Neurosurgery 77:380–385, 2015

Carotid cavernous fistulae (CCFs) are most commonly classified based on arterial supply. Symptomatology and treatment approach, however, are largely influenced by venous drainage.

OBJECTIVE: To propose an updated classification system using venous drainage.

METHODS: CCFs with posterior/inferior drainage only, posterior/inferior and anterior drainage, anterior drainage only, and retrograde drainage into cortical veins with/without other drainage channels were designated as types 1, 2, 3, and 4, respectively. CCFs involving a direct connection between the internal carotid artery and cavernous sinus were designated as type 5. This system was retrospectively applied to 29 CCF patients.

RESULTS: Our proposed classification was significantly associated with symptomatology (P , .001). Type 2 was significantly associated with coexisting ocular/orbital and cavernous symptoms only (P , .001), type 3 with ocular/orbital symptoms only (P , .01), and type 4 demonstrated cortical symptoms with/without ocular/orbital and cavernous symptoms (P , .01), respectively. There was a significant association of our classification system with the endovascular treatment approach (P , .001). Types 1 and 2 were significantly associated with endovascular treatment through the inferior petrosal sinus (P , .01). Type 3 was significantly associated with endovascular treatment through the ophthalmic vein (P , .01) and type 5 with transarterial approach (P , .01), respectively. Types 2 (27.6%) and 3 (34.5%) were most prevalent in this series, whereas type 1 was rare (6.9%), suggesting that some degree of thrombosis is present, with implications for spontaneous resolution. Type 2 CCFs demonstrated a trend toward partial resolution after endovascular treatment (P = .07).

CONCLUSION: Our proposed classification system is easily applicable in clinical practice and demonstrates correlation with symptomatology, treatment approach, and outcome.

07/09/201506/09/2015

The 6 thalamic regions: surgical approaches to thalamic cavernous malformations, operative results, and clinical outcomes

J Neurosurg (123)3: 676-685

The ideal surgical approach to thalamic cavernous malformations (CMs) varies according to their location within the thalamus. To standardize surgical approaches, the authors have divided the thalamus into 6 different regions and matched them with the corresponding surgical approach.

METHODS
The regions were defined as Region 1 (anteroinferior), Region 2 (medial), Region 3 (lateral), Region 4 (posterosuperior), Region 5 (lateral posteroinferior), and Region 6 (medial posteroinferior). The senior author’s surgical experience with 46 thalamic CMs was reviewed according to this classification. An orbitozygomatic approach was used for Region 1; anterior ipsilateral transcallosal for Region 2; anterior contralateral transcallosal for Region 3; posterior transcallosal for Region 4; parietooccipital transventricularfor Region 5; and supracerebellar-infratentorial for Region 6.

RESULTS
Region 3 was the most common location (17 [37%]). There were 5 CMs in Region 1 (11%), 9 in Region 2 (20%), 17 in Region 3 (37%), 3 in Region 4 (6%), 4 in Region 5 (9%), and 8 in Region 6 (17%). Complete resection was achieved in all patients except for 2, who required a second-stage operation. The mean follow-up period was 1.7 years (range 6 months-9 years). At the last clinical follow-up, 40 patients (87%) had an excellent or good outcome (modified Rankin Scale [mRS] scores 0–2) and 6 (13%) had poor outcome (mRS scores 3–4). Relative to their preoperative condition, 42 patients (91%) were unchanged or improved, and 4 (9%) were worse.

CONCLUSIONS
The authors have presented the largest series reported to date of surgically treated thalamic CMs, achieving excellent results using this methodology. In the authors’ experience, conceptually dividing the thalamus into 6 different regions aids in the selection of the ideal surgical approach for a specific region.

03/09/201530/08/2015

Neuropsychological assessment after aneurysmal subarachnoid hemorrhage: Swiss recommendations

Acta Neurochirurgica 157 (9):1449-1458

In a high proportion of patients with favorable outcome after aneurysmal subarachnoid hemorrhage (aSAH), neuropsychological deficits, depression, anxiety, and fatigue are responsible for the inability to return to their regular premorbid life and pursue their professional careers. These problems often remain unrecognized, as no recommendations concerning a standardized comprehensive assessment have yet found entry into clinical routines.
Methods
To establish a nationwide standard concerning a comprehensive assessment after aSAH, representatives of all neuropsychological and neurosurgical departments of those eight Swiss centers treating acute aSAH have agreed on a common protocol. In addition, a battery of questionnaires and neuropsychological tests was selected, optimally suited to the deficits found most prevalent in aSAH patients that was available in different languages and standardized.
Results
We propose a baseline inpatient neuropsychological screening using the Montreal Cognitive Assessment (MoCA) between days 14 and 28 after aSAH. In an outpatient setting at 3 and 12 months after bleeding, we recommend a neuropsychological examination, testing all relevant domains including attention, speed of information processing, executive functions, verbal and visual learning/memory, language, visuo-perceptual abilities, and premorbid intelligence. In addition, a detailed assessment capturing anxiety, depression, fatigue, symptoms of frontal lobe affection, and quality of life should be performed.
Conclusions
This standardized neuropsychological assessment will lead to a more comprehensive assessment of the patient, facilitate the detection and subsequent treatment of previously unrecognized but relevant impairments, and help to determine the incidence, characteristics, modifiable risk factors, and the clinical course of these impairments after aSAH.

01/09/201529/08/2015

High Subarachnoid Hemorrhage Patient Volume Associated With Lower Mortality and Better Outcomes

Neurosurgery 77:462–470, 2015

High-volume centers have better outcomes than low-volume centers when managing complex conditions including subarachnoid hemorrhage (SAH).

OBJECTIVE: To quantify SAH volume-outcome association and determine the extent to which this association is influenced by aggressiveness of care.

METHODS: A serial cross-sectional retrospective study using the Nationwide Inpatient Sample for 2002 to 2010 was performed. Included were all adult (older than 18 years of age) discharged patients with a primary diagnosis of SAH admitted from the emergency department or transferred to a discharging hospital; cases of trauma or arteriovenous malformation were excluded. Survey-weighted descriptive statistics estimated temporal trends. Multilevel logistic regression estimated volume-outcome associations for inpatient mortality and discharge home. Models were adjusted for demographic characteristics, year, transfer status, insurance status, all individual Charlson comorbidities, intubation, and all patient-refined, diagnosis-related group mortality. Analyses were repeated, excluding cases in which aggressive care was not pursued.

RESULTS: A total of 32336 discharges were included; 13398 patients underwent clipping (59.1%) or coiling (40.9%). The inpatient mortality rate decreased from 32.2% in 2002 to 22.2% in 2010; discharge home increased from 28.5% to 40.8% during the same period. As SAH volume decreased from 100/year, the mortality rate increased from 18.7% to 19.8% at 80/year, 21.7% at 60/year, 24.5% at 40/year, and 28.4% at 20/ year. As SAH patient volume decreased, the probability of discharge home decreased from 40.3% at 100/year to 38.7% at 60/year, and 35.3% at 20/year. Better outcomes persisted in patients receiving aggressive care and in those not receiving aggressive care.

CONCLUSION: Short-term SAH outcomes have improved. High-volume hospitals have more favorable outcomes than low-volume hospitals. This effect is substantial, even for hospitals conventionally classified as high volume.

31/08/201529/08/2015

Isolated cortical vein thrombosis

J Neurosurg 123:427–433, 2015

Isolated cortical vein thrombosis (ICVT) accounts for less than 1% of all cerebral infarctions. ICVT may cause irreversible parenchymal damage, rendering early and accurate diagnosis critical. This case series and literature review presents the clinical and radiological findings in 7 patients with ICVT, and highlights risk factors and imaging modalities that may be most beneficial in rendering an accurate and timely diagnosis.

Methods Patients with CT and MRI findings consistent with ICVT examined between January 2011 and June 2014 were included in this retrospective review.

Results Seven patients (5 females, 2 males), ranging in age from 11 months to 34 years, met the inclusion criteria. The most common clinical presentations were headaches (n = 4) and seizures (n = 3). The most common comorbidities noted in these patients were hypercoagulable states (n = 4) and intracranial hypotension (n = 3). Five patients had intraparenchymal involvement. CT suggested the correct diagnosis in 4 patients, and MRI confirmed the diagnosis in all 7 patients. All patients who received anticoagulation therapy (n = 5) experienced complete resolution of their symptoms.

Conclusions The majority of these patients were adult females, consistent with published data. Seizures and headaches were the most common presenting symptoms. Hypercoagulable state and intracranial hypotension, both known risk factors for thrombosis, were the most commonly noted ICVT risk factors. Intraparenchymal involvement was prevalent in nearly all ICVT cases and presented as vasogenic edema, early intraparenchymal hemorrhage, or hemorrhagic venous infarction. Susceptibility-weighted imaging was the most sensitive imaging technique in diagnosing ICVT.

26/08/201525/08/2015

Clinical characteristics and long-term outcomes in patients with ruptured posterior inferior cerebellar artery aneurysms

J Neurosurg 123:441–445, 2015

Subarachnoid hemorrhage (SAH) from ruptured posterior inferior cerebellar artery (PICA) aneurysms is uncommon, and long-term outcome data for patients who have suffered such hemorrhages is lacking. This study investigated in-hospital and long-term clinical data from a prospective cohort of patients with SAH from ruptured PICA aneurysms enrolled in a randomized trial; their outcomes were compared with those of SAH patients who were treated for other types of ruptured intracranial aneurysms. The authors hypothesize that PICA patients fare worse than those with aneurysms in other locations and this difference is related to the high rate of lower cranial nerve dysfunction in PICA patients.

Methods The authors analyzed data for 472 patients enrolled in the Barrow Ruptured Aneurysm Trial (BRAT) and retrospectively reviewed vasospasm data not collected prospectively. In the initial cohort, 57 patients were considered angiographically negative for aneurysmal SAH source and did not receive treatment for aneurysms, leaving 415 patients with aneurysmal SAH.

Results Of 415 patients with aneurysmal SAH, 22 (5.3%) harbored a ruptured PICA aneurysm. Eight of them had dissecting/ fusiform-type aneurysms while 14 had saccular-type aneurysms. Nineteen PICA patients were treated with clipping (1 crossover from coiling), 2 were treated with coiling, and 1 died before treatment. When comparing PICA patients to all other aneurysm patients in the study cohort, there were no statistically significant differences in age (mean 57.6 ± 11.8 vs 53.9 ± 11.8 years, p = 0.17), Hunt and Hess grade median III [IQR II–IV] vs III [IQR II–III], p = 0.15), Fisher grade median 3 [IQR 3–3] vs 3 [IQR 3–3], p = 0.53), aneurysm size (mean 6.2 ± 3.0 vs 6.7 ± 4.0 mm, p = 0.55), radiographic vasospasm (53% vs 50%, p = 0.88), or clinical vasospasm (12% vs 23%, p = 0.38). PICA patients were more likely to have a fusiform aneurysm (36% vs 12%, p = 0.004) and had a higher incidence of lower cranial nerve dysfunction and higher rate of tracheostomy/percutaneous endoscopic gastrostomy placement compared with non-PICA patients (50% vs 16%, p < 0.001). PICA patients had a significantly higher incidence of poor outcome at discharge (91% vs 67%, p = 0.017), 1-year follow-up (63% vs 29%, p = 0.002), and 3-year follow-up (63% vs 32%, p = 0.006).

Conclusions Patients with ruptured PICA aneurysms had a similar rate of radiographic vasospasm, equivalent admission Fisher grade and Hunt and Hess scores, but poorer clinical outcomes at discharge and at 1- and 3-year followup when compared with the rest of the BRAT SAH patients with ruptured aneurysms. The PICA’s location at the medulla and the resultant high rate of lower cranial nerve dysfunction may play a role in the poor outcome for these patients. Furthermore, PICA aneurysms were more likely to be fusiform than saccular, compared with non-PICA aneurysms; the complex nature of these aneurysms may also contribute to their poorer outcome.

24/08/201523/08/2015

Suture retraction technique to prevent parent vessel obstruction following aneurysm tandem clipping

J Neurosurg 123:472–474, 2015

With large or giant aneurysms, the use of multiple tandem clips can be essential for complete obliteration of the aneurysm. One potential disadvantage, however, is the considerable cumulative weight of these clips, which may lead to kinking of the underlying parent vessels and obstruction of flow.

The authors describe a simple technique to address this problem, guided by intraoperative blood flow measurements, in a patient with a ruptured near-giant 2.2 × 1.7–cm middle cerebral artery bifurcation aneurysm that was treated with the tandem clipping technique. A total of 11 clips were applied in a vertical stacked fashion. The cumulative weight of the clips caused kinking of the temporal M2 branch of the bifurcation with reduction of flow. A 4-0 Nurolon suture tie was applied to the hub of one of the clips and was tethered to the dura of the sphenoid ridge by a small mini-clip and reinforced by application of tissue sealant. The patient underwent intraoperative indocyanine green videoangiography as well as catheter angiography, which demonstrated complete aneurysmal obliteration and preservation of vessel branches. Postoperative angiography confirmed patency of the bifurcation vessels with mild vasospasm. The patient had a full recovery with no postoperative complications and was neurologically intact at her 6-month follow-up.

The suture retraction technique allows a simple solution to parent vessel obstruction following aneurysm tandem clipping, in conjunction with the essential guidance provided by intraoperative flow measurements.

12/08/201520/04/2020

Pericallosal aneurysm: A difficult challenge for microsurgery and endovascular treatment

Neurochirurgie 61 (2015) 244–249

Pericallosal artery aneurysms (PAA) represent 2 to 9% of intracranial aneurysms and their management remains difficult.

Objective. We aimed to report our experience to evaluate the outcome of patients with ruptured and unruptured PAA, when the treatment modality is decided in a multidisciplinary fashion.

Materials and methods. In this retrospective study, we included 28 patients (8 men and 20 women) treated for a PAA in our institution between 2002 and 2012, among the 2430 patients who underwent the treatment of an intracranial aneurysm in the same period. Fifteen patients harbored a ruptured aneurysm while 13 benefited from a prophylactic treatment. The mean age at diagnosis was 52 years (range 37 to 75 SD: ±5) in patients with ruptured aneurysm and 54.2 years (range 35 to 66 SD: ±5) in patients with unruptured aneurysm. Endovascular treatment has been performed in 9 patients while 19 patients underwent a microsurgical treatment. Clinical outcome has been assessed using the modified Rankin scale (mRS) at 3 months. Long-term imaging follow-up included a CT angiography at 36 months for clipped aneurysms and MR angiography at 6, 18 and 36 months for coiled aneurysms.

Results. The median follow-up was 3.4 years (range 2.8 to 4.2). The mRS was ≤ 2 in all patients with unruptured aneurysms. In patients with ruptured aneurysm, the mRS was ≤ 2 at 3 months in 13 patients (87%). Persistent cognitive disorders were noted in 8 patients with ruptured aneurysm, 2 of them were considered as possibly related to the treatment. Aneurysm recurrence has been depicted in 4 patients (at 6 months in 3 patients and 1 year in 1 patient) requiring further treatment in all cases; all of them had an aneurysm remnant on immediate conventional angiography. No recurrence was noted in patients without remnant on immediate post-treatment angiography.

Conclusion. Both endovascular and microsurgical treatment are challenged in this location. Multidisciplinary discussion is essential to optimize the management of patients with PAA

10/08/201509/08/2015

Validation of a System to Predict Recanalization After Endovascular Treatment of Intracranial Aneurysms

Neurosurgery 77:168–174, 2015

With increasing use of endovascular techniques in the treatment of ruptured and unruptured aneurysms, the issue of obliteration efficacy has become increasingly important. We have previously reported the Aneurysm Recanalization Stratification Scale, which uses accessible predictors including aneurysm-specific factors (size, rupture, and intraluminal thrombosis) and treatment-related features (treatment modality and immediate angiographic result) to predict retreatment risk after endovascular therapy.

OBJECTIVE: To assess the external validity of the Aneurysm Recanalization Stratification Scale.

METHODS: External validity was assessed in independent cohorts from 4 centers in the United States and Canada where endovascular and open neurovascular procedures are performed, and in a multicenter cohort of 1543 patients. Probability of retreatment stratified by risk score was derived for each center and the combined multicenter cohort.

RESULTS: Despite moderate variability in retreatment rate among centers (29.5%, 9.9%, 9.6%, 26.3%, 19.7%, and 18.3%), the Aneurysm Recanalization Stratification Scale demonstrated good predictive value with C-statistics of 0.799, 0.943, 0.780, 0.695, 0.755, and 0.719 for each center and the combined cohort, respectively. Probability of retreatment stratified by risk score for the combined cohort is as follows: -2, 4.9%; -1, 5.7%; 0, 5.8%; 1, 13.1%; 2, 19.2%; 3, 34.9%; 4, 32.7%; 5, 73.2%; 6, 89.5%; and 7, 100.0%.

CONCLUSION: Surgical decision-making and patient-centered informed consent require comprehensive and accessible information on treatment efficacy. The Aneurysm Recanalization Stratification Scale is a valid prognostic index. This is the first comprehensive model that has been developed to quantitatively predict retreatment risk following endovascular therapy.

28/07/201526/07/2015

Serial Imaging Surveillance for Patients With a History of Intracranial Aneurysm: Risk of De Novo Aneurysm Formation

Neurosurgery 77:32–43, 2015

Although rare, de novo intracranial aneurysms (DNIAs) may develop in patients with a history of intracranial aneurysms (IAs).

OBJECTIVE: To evaluate the benefit of routine radiographic screening for DNIAs.

METHODS: Data for 2153 patients with IAs were retrospectively analyzed. A total of 185 patients underwent screening for DNIAs at frequent intervals.

RESULTS: Overall, DNIAs were detected in 26 patients (1.2%). Of the 185 patients with surveillance, DNIAs developed in 9 (4.9%). The risk of DNIA detection was 1.14% per person-year of follow-up (95% confidence interval: 0.6%-2.2%). Patients with imaging follow-up had a significantly higher rate of DNIA detection compared with patients without regular imaging surveillance (4.9% vs 0.86%; P , .001), but surveillance was associated with smaller lesions (with surveillance: 3.8 6 1.8 mm, without: 7.0 6 4.4 mm, mean 6 standard deviation; P = .026). A unimodal distribution of time to detection was found in those with surveillance, with a peak between 0 and 2 years. There was a trend toward an association of cigarette smoking and DNIA detection within 10 years (P = .06); 6 of the 26 patients (23.1%) with DNIAs had a history of cigarette smoking, with all 6 patients continuing to smoke up to the detection of the DNIAs, which were detected in 2.5 6 1.8 years.

CONCLUSION: The low 1.14% per-person year risk of DNIA detection and small DNIA size at detection cannot justify routine screening for DNIAs in all patients with a personal history of IAs. If imaging follow-up is considered for selected patients, early screening will likely yield the most benefit in patients who continue to smoke cigarettes.

14/07/201513/07/2015

Bur hole craniostomy for chronic subdural hematoma

J Neurosurg 123:65–74, 2015

There is inconsistency among the perioperative management strategies currently used for chronic subdural hematoma (cSDH). Moreover, postoperative complications such as acute intracranial bleeding and cSDH recurrence affect clinical outcome of cSDH surgery. This study evaluated the risk factors associated with acute intracranial bleeding and cSDH recurrence and identified an effective perioperative strategy for cSDH patients.

Methods A retrospective study of patients who underwent bur hole craniostomy for cSDH between 2008 and 2012 was performed.

Results A consecutive series of 303 cSDH patients (234 males and 69 females; mean age 67.17 years) was analyzed. Postoperative acute intracranial bleeding developed in 14 patients (4.57%) within a mean of 3.07 days and recurrence was observed in 37 patients (12.21%) within a mean of 31.69 days (range 10–104 days) after initial bur hole craniostomy. The comorbidities of hematological disease and prior shunt surgery were clinical factors associated with acute bleeding. There was a significant risk of recurrence in patients with diabetes mellitus, but recurrence did not affect the final neurological outcome (p = 0.776). Surgical details, including the number of operative bur holes, saline irrigation of the hematoma cavity, use of a drain, and type of postoperative ambulation, were not significantly associated with outcome. However, a large amount of drainage was associated with postoperative acute bleeding.

Conclusions Bur hole craniostomy is an effective surgical procedure for initial and recurrent cSDH. Patients with hematological disease or a history of prior shunt surgery are at risk for postoperative acute bleeding; therefore, these patients should be carefully monitored to avoid overdrainage. Surgeons should consider informing patients with diabetes mellitus that this comorbidity is associated with an increased likelihood of recurrence.

13/07/201520/04/2020

Contralateral Approach to Internal Carotid Artery Ophthalmic Segment Aneurysms: Angiographic Analysis and Surgical Results for 30 Patients

Neurosurgery. 77(1):104-112, July 2015

Contralateral aneurysm clipping can be applied to bilateral intracranial aneurysms of the anterior circulation and to selected aneurysms on the medial wall of the internal carotid artery (ICA).

OBJECTIVE: To identify anatomic and radiological parameters that would favor a contralateral microsurgical approach to ICA–ophthalmic segment (ICA-opht) aneurysms.

METHODS: For the period January 1957 to December 2012, we retrospectively analyzed 268 patients with ICA-opht aneurysms treated in our institution. Of these patients, 30 underwent a contralateral approach; 15 patients (50%) had multiple intracranial aneurysms, and 15 patients had a single aneurysm on the contralateral side of the craniotomy.

RESULTS: Thirty saccular aneurysms located on the contralateral ICA were treated. Six aneurysms (20%) were present in patients with a subarachnoid hemorrhage due to associated aneurysms, whereas 24 aneurysms (80%) had no history of bleeding. Contralateral aneurysms were smaller than 14 mm and showed no wall irregularities, calcifications, or secondary pouches. Projections of the aneurysms were superomedial (n = 23, 77%), medial (n = 4, 13%), and superior (n = 3, 10%). The median prechiasmatic distance was 5.7 mm (range, 3.4-8.7 mm), the median interoptic distance was 10.5 mm (range, 7.6-15.9 mm), and the median distance between both ICAs was 14.7 mm (range, 10.4-21.4 mm).

CONCLUSION: The contralateral approach for ICA-opht aneurysms remains a treatment option for intracranial aneurysms. Its feasibility depends on specific anatomic parameters related to the aneurysm itself and to the prechiasmatic distance, interoptic distance, and relationship of the ICA with the anterior clinoid process.

10/07/201509/07/2015

Smoking and Intracranial Aneurysm Morphology

Neurosurgery 77:59–66, 2015

Smoking is a well-known independent risk factor for both aneurysm formation and rupture. There is mounting evidence that aneurysm morphology beyond size can have a significant role in aneurysm formation and rupture risk by its effects on aneurysmal hemodynamics.

OBJECTIVE: To study the variation in aneurysm morphology between smokers and nonsmokers and delineate how changes in these factors might affect aneurysm formation and rupture.

METHODS: We generated 3-dimensional models of aneurysms and their surrounding vasculature by analyzing preoperative computed tomography angiograms with Slicer software. We then examined the association between smoking status and intrinsic, transitional, and extrinsic aspects of aneurysm morphology in both univariate and multivariate statistical analyses.

RESULTS: From 2005 to 2013, 199 cerebral aneurysms in never smokers and current smokers were evaluated/treated at a single institution with available computed tomography angiograms (102 in never smokers and 97 in current smokers). Multivariate analysis of current smokers vs never smokers demonstrated that aneurysms in current smokers were significantly associated with multiple aneurysms (odds ratio [OR]: 2.15, P = .03), larger daughter vessel diameters (OR: 3.13, P = .01), larger size ratio (OR: 1.78, P = .01), and location at the basilar apex (OR: 6.26, P = .02).

CONCLUSION: The differences in aneurysm morphology between smoking and nonsmoking patient populations may elucidate the effects of smoking on aneurysm formation and eventual rupture. We identified several aspects of aneurysm morphology significantly associated with smoking status that may provide the morphological basis for how smoking leads to increased aneurysm rupture.

25/06/201524/06/2015

Viability of Anastomoses With Coupler in Extra-Intracranial Bypass

Operative Neurosurgery 11:235–242, 2015

The time required to perform an anastomosis in extra-intracranial bypass is approximately 20 to 60 minutes. The search for alternative methods to reduce the ischemic time remains vital.

OBJECTIVE: To evaluate Coupler anastomosis for extra-intracranial bypass in cadavers.

METHODS: In 8 fresh adult cadavers, the saphenous vein and radial artery were used as donor vessels. The superficial temporal and the extracranial internal and external carotid arteries were dissected. A wide craniotomy with a sylvian fissure opening was performed, exposing the middle cerebral and supraclinoid internal carotid arteries. The Coupler devices were tested in all 8 cadavers. The diameter of the donor and recipient vessels as well as the time required to perform the anastomosis were measured. Bypass permeability was evaluated by injecting saline solution under pressure, checking for leaks.

RESULTS: The anastomoses were successfully performed in all specimens. The size of the head of the fitting Coupler required the performance of a wide craniotomy (6 · 6 cm) and a wide opening of the sylvian fissure. The time required to perform each anastomosis ranged from 4 to 7 minutes, being easier with the radial artery than with the saphenous vein.

CONCLUSION: Coupler devices are helpful to perform the anastomoses, because they significantly reduce ischemia time. Their use is easier at the M1 segment, just before the bifurcation and after takeoff of the lenticulostriate arteries, and in the M2 segment. It would be advisable to have a smaller coupling system, allowing maneuverability in the deeper areas where space is limited.

24/06/201521/06/2015

Intraoperative Flow Measurement by Microflow Probe During Surgery for Brain Arteriovenous Malformations

Operative Neurosurgery 11:268–273, 2015

Intraoperative quantitative flow measurement by a microvascular ultrasonic flow probe is an established methodology in aneurysm surgery.

OBJECTIVE: To test the present flow measurement procedure in brain arteriovenous malformation (AVM) surgery.

METHODS: Data from 25 patients with brain AVMs who consecutively underwent microsurgical resection with the assistance of flow measurement by a microflow probe were retrospectively analyzed. Flowmetry was performed on arterial feeders, potentially transit arteries, and venous drainage of AVM in different phases of resection.

RESULTS: A quantitative flow measurement was performed 203 times on 92 vessels. Flowmetry was able to define the flow direction of AVM vessels in all cases, thereby discriminating between arterial feeders and venous drainages, both superficially and deeply located. During AVM dissection, flowmetry identified a transit artery in 12% of cases by detecting a flow drop between 2 points of the same vessel. At the final stage of resection, a residual nidus, potentially missed at surgical dissection, was detected when the flow value of venous drainage was greater than 4 mL/min (20% of patients). Preresection microflow probe measurements were concordant with indocyanine green videoangiography data on AVM angioarchitecture in all cases. No microflow probe– induced AVM vessel injury was reported. Complete AVM resection was achieved in all cases with a low morbidity (modified Rankin Scale score #1).

CONCLUSION: Multistage intraoperative quantitative flow measurement proved to be a feasible, safe, repeatable, and reliable methodology to assist surgery in different phases of AVM resection. Further studies are needed to assess the impact of this approach on AVM patient outcomes.

18/06/201517/06/2015

Morphological Parameters Associated With Middle Cerebral Artery Aneurysms

Neurosurgery 76:721–727, 2015

Morphological factors contribute to the hemodynamics of the middle cerebral artery (MCA).

OBJECTIVE: To identify image-based morphological parameters that correlated with the presence of MCA aneurysms.

METHODS: Image-based anatomic parameters obtained from 110 patients with and without MCA bifurcation aneurysms were evaluated with Slicer, an open-source image analysis software, to generate 3-dimensional models of the aneurysms and surrounding vascular architecture. We examined segment lengths, diameters, and vessel-to-vessel angles of the parent and daughter vessels at the MCA bifurcation. In order to reduce confounding by genetic and clinical risk factors, 2 control groups were selected: group A (the unaffected contralateral side of patients with unilateral MCA bifurcation aneurysms) and group B (patients without intracranial aneurysms or other vascular malformations). Univariate and multivariate analyses were performed to determine statistical significance.

RESULTS: One hundred ten patients who were evaluated from 2007 to 2014 were analyzed (73 patients with MCA aneurysms and 37 control patients). Multivariate analysis revealed that a smaller parent artery diameter (group A: odds ratio [OR] 0.20, P < .01, group B: OR 0.23, P < .01) and a larger daughter-to-daughter branch angle (group A: OR 1.01, P = .04, group B: OR 1.02, P = .04) were most strongly associated with MCA aneurysm presence after adjusting for other morphological factors.

CONCLUSION: Smaller parent artery diameter and larger daughter-to-daughter branch angles are associated with the presence of MCA bifurcation aneurysms. These easily measurable parameters may provide objective metrics to assess aneurysm formation and growth risk stratification in high-risk patients.

08/06/201506/06/2015

Integration of Indocyanine Green Videoangiography With Operative Microscope: Augmented Reality for Interactive Assessment of Vascular Structures and Blood Flow

Operative Neurosurgery 11:252–258, 2015

Preservation of adequate blood flow and exclusion of flow from lesions are key concepts of vascular neurosurgery. Indocyanine green (ICG) fluorescence videoangiography is now widely used for the intraoperative assessment of vessel patency.

OBJECTIVE: Here, we present a proof-of-concept investigation of fluorescence angiography with augmented microscopy enhancement: real-time overlay of fluorescence videoangiography within the white light field of view of conventional operative microscopy.

METHODS: The femoral artery was exposed in 7 anesthetized rats. The dissection microscope was augmented to integrate real-time electronically processed near-infrared filtered images with conventional white light images seen through the standard oculars. This was accomplished by using an integrated organic light-emitting diode display to yield superimposition of white light and processed near-infrared images. ICG solution was injected into the jugular vein, and fluorescent femoral artery flow was observed.

RESULTS: Fluorescence angiography with augmented microscopy enhancement was able to detect ICG fluorescence in a small artery of interest. Fluorescence appeared as a bright-green signal in the ocular overlaid with the anatomic image and limited to the anatomic borders of the femoral artery and its branches. Surrounding anatomic structures were clearly visualized. Observation of ICG within the vessel lumens permitted visualization of the blood flow. Recorded video loops could be reviewed in an offline mode for more detailed assessment of the vasculature.

CONCLUSION: The overlay of fluorescence videoangiography within the field of view of the white light operative microscope allows real-time assessment of the blood flow within vessels during simultaneous surgical manipulation. This technique could improve intraoperative decision making during complex neurovascular procedures.

29/05/201527/05/2015

Radiosurgery for symptomatic cavernous malformations: A multi‑institutional retrospective study in Japan

Surg Neurol Int 2015;6:S249-57

A group study for symptomatic cavernous malformation (CM) treated with gamma knife (GK) surgery was performed.

Methods: A total of 298 cases collected from 23 GK centers across Japan were included. Hemorrhage was the most common manifestation, followed by seizures and neurological deficits. Most of the lesions were located in the brainstem and basal ganglia, followed by the cerebral or cerebellar hemispheres. The CMs, which had a mean diameter of 14.8 mm, were treated using GK surgery with a mean marginal dose of 14.6 Gy.

Results: In terms of hemorrhage‑free survival (HFS), a marked dissociation was confirmed between the hemorrhage and seizure groups, while no obvious difference was noted between sexes. Superficial CMs located in cerebellum or lobar regions responded to the treatment better than deeply located CMs in the basal ganglia or brainstem. No significant difference of dose‑dependent response was seen for three different ranges of marginal dose: Less than 15 Gy, between 15 and 20 Gy, and more than 20 Gy. Complications were more frequent after a marginal dose of over 15 Gy and in patients with lesions more than 15 mm in diameter. The rates of annual hemorrhage were estimated to be 7.4% during the first 2 years after radiosurgery and 2.8% thereafter. The overall hemorrhage rate after radiosurgery was 4.4%/year/patient.

Conclusion: The risk of hemorrhage is considerably reduced after GK treatment. The HFS as well as annual hemorrhage rate after GK treatment was apparently superior to that after conservative treatment for symptomatic CMs. To optimize the success of GK treatment, it is important to reduce the incidence of complications.

27/05/201524/05/2015

Long-term Functional Outcomes and Predictors of Shunt-Dependent Hydrocephalus After Treatment of Ruptured Intracranial Aneurysms in the BRAT Trial: Revisiting the Clip vs Coil Debate

Neurosurgery 76:608–615, 2015

Acute hydrocephalus is a well-known sequela of aneurysmal subarachnoid hemorrhage (SAH). Controversy exists about whether open microsurgical methods serve to reduce shunt dependency compared with endovascular techniques.

OBJECTIVE: To determine predictors of shunt-dependent hydrocephalus and functional outcomes after aneurysmal SAH.

METHODS: A total of 471 patients who were part of a prospective, randomized, controlled trial from 2003 to 2007 were retrospectively reviewed. All variables including demographic data, medical history, treatment, imaging, and functional outcomes were included as part of the trial. No additional variables were retrospectively collected.

RESULTS: Ultimately, 147 patients (31.2%) required a ventriculoperitoneal shunt (VPS) in our series. Age, dissecting aneurysm type, ruptured vertebrobasilar aneurysm, Fisher grade, Hunt and Hess grade, admission intraventricular hemorrhage, admission intraparenchymal hemorrhage, blood in the fourth ventricle on admission, perioperative ventriculostomy, and hemicraniectomy were significant risk factors (P < .05) associated with shunt-dependent hydrocephalus on univariate analysis. On multivariate analysis, intraventricular hemorrhage and intraparenchymal hemorrhage were independent risk factors for shunt dependency (P< .05). Clipping vs coiling treatment was not statistically associated with VPS after SAH on both univariate and multivariate analyses. Patients who did not receive a VPS at discharge had higher Glasgow Outcome Scale and Barthel Index scores and were more likely to be functionally independent and to return to work 72 months after surgery (P < .05).

CONCLUSION: There is no difference in shunt dependency after SAH among patients treated by endovascular or microsurgical means. Patients in whom shunt-dependent hydrocephalus does not develop after SAH tend to have improved long-term functional outcomes.

25/05/201524/05/2015

Treatment Outcomes of Unruptured Arteriovenous Malformations With a Subgroup Analysis of ARUBA Eligible Patients

Neurosurgery 76:563–570, 2015

The design and conclusions of A Randomized Trial of Unruptured Brain Arteriovenous Malformations (ARUBA) trial are controversial, and its structure limits analysis of patients who could potentially benefit from treatment.

OBJECTIVE: To analyze the results of a consecutive series of patients with unruptured brain arteriovenous malformations (BAVMs), including a subgroup analysis of ARUBAeligible patients.

METHODS: One hundred five patients with unruptured BAVMs were treated over an 8-year period. From this series, 90 adult patients and a subgroup of 61 patients determined to be ARUBA eligible were retrospectively reviewed. A subgroup analysis for Spetzler-Martin grades I/II, III, and IV/V was performed. The modified Rankin Scale was used to assess functional outcome.

RESULTS: Persistent deficits, modified Rankin Scale score deterioration, and impaired functional outcome occurred less frequently in ARUBA-eligible grade I/II patients compared with grade III to V patients combined (P = .04, P = .04, P = .03, respectively). Twenty-two of 39 patients (56%) unruptured grade I and II BAVMs were treated with surgery without and with preoperative embolization, and all had a modified Rankin Scale score of 0 to 1 at the last follow-up. All patients treated with surgery without and with preoperative embolization had radiographic cure at the last follow-up.

CONCLUSION: The results of ARUBA-eligible and unruptured grade I/II patients overall show that excellent outcomes can be obtained in this subgroup of patients, especially with surgical management. Functional outcomes for ARUBA-eligible patients were similar to those of patients who were randomized to medical management in ARUBA. On the basis of these data, in appropriately selected patients, we recommend treatment for low-grade BAVMs.

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