Vascular stability of brain arteriovenous malformations after partial embolization

INTRODUCTION

Brain arteriovenous malformation (bAVM) might have a higher risk of rupture after partial embolization, and previous studies have shown that some metrics of vascular stability are related to bAVM rupture risk.

OBJECTIVE

To analyze vascular stability of bAVM in patients after partial embolization.

METHODS

Twenty-four patients who underwent partial embolization were classified into the short-term, medium-term, and long-term groups, according to the time interval between partial embolization and surgery. The control group consisted of 9 bAVM patients who underwent surgery alone. Hemodynamic changes after partial embolization were measured by angiogram. The inflammatory infiltrates and cell-cell junctions were evaluated by MMP-9 and VE-cadherin. At the protein level, the proliferative and apoptotic events of bAVMs were analyzed by immunohistochemical staining of VEGFA, eNOS, and caspase-3. Finally, neovascularity and apoptotic cells were assessed by CD31 staining and TUNEL staining.

RESULTS

Immediately after partial embolization, the blood flow velocity of most bAVMs increased. The quantity of MMP-9 in the medium-term group was the highest, and VE-cadherin in the medium-term group was the lowest. The expression levels of VEGFA, eNOS, and neovascularity were highest in the medium-term group. Similarly, the expression level of caspase-3 and the number of apoptotic cells were highest in the medium-term group.

CONCLUSION

The biomarkers for bAVM vascular stability were most abnormal between 1 and 28 days after partial embolization.

Application of protective superficial temporal artery to middle cerebral artery bypass through the lateral supraorbital approach: Technical note

OBJECTIVE

The lateral supraorbital (LSO) approach is a minimally invasive craniotomy widely used in the surgical treatment of intracranial aneurysms (IAs). A protective bypass is considered a safety measure in high-risk and complex clipping procedures to maintain distal cerebral flow. However, the protective bypass has so far only been applied through a pterional or larger craniotomy. We aimed to describe the characteristics of the superficial temporal artery to middle cerebral artery (STA-MCA) bypass through the LSO craniotomy to treat complex IAs.

METHODS

We retrospectively identified six patients with complex IAs who underwent clipping and a protective STA-MCA bypass through the LSO approach between January 2016 and December 2020. The STA donor artery was harvested through the same curvilinear skin incision with a small extension, and it was anastomosed to the opercular segment of the MCA. Subsequently, aneurysm clipping followed standardized steps.

RESULTS

Anastomosis was successful in all patients. Despite requiring temporary occlusion of the parent artery, all aneurysms were successfully clipped without any neurological deterioration.

CONCLUSIONS

A protective STA-MCA bypass is feasible through the LSO approach with certain technical modifications. This technique helps protect distal cerebral flow for safe clip placement in the treatment of complex IAs with the associated benefits of a less invasive craniotomy.

Superficial Temporal Artery: Distal Posterior Cerebral Artery Bypass through the Subtemporal Approach: Technical Note and Pilot Surgical Cases

BACKGROUND: Posterior cerebral artery (PCA) aneurysms are rare and the majority are fusiform in shape. Proximal occlusion of PCA represents a treatment option for these lesions. However, this procedure carries a high risk of ischemic complications.

OBJECTIVE: To describe the technique of trapping a fusiform PCA aneurysm and revascularization of the distal PCA using a superficial temporal artery (STA) graft through the same microsurgical approach.

METHODS: From September 2012 to October 2014, we retrospectively identified 3 patients harboring a fusiform PCA aneurysm (P2 segment aneurysm) who underwent trapping of the aneurysm and reconstruction of the distal PCA through the same subtemporal approach. We analyzed immediate morbidity, surgical complications, and the patency of the bypass to determine the feasibility of this procedure.

RESULTS: All 3 patients underwent successful trapping of the fusiform PCA aneurysm and revascularization of the distal PCA. The origin of P3 segment or posterior temporal artery (PTA) served as recipient arteries. In all 3 cases, adequate blood flow was evident after performing the STA-P3/PTA bypass. None of the patients experienced a new permanent neurological deficit. At 1-year follow-up, the STA-PTA/PCA bypasses remained patent.

CONCLUSION: The STA-P3/PTA bypass through the subtemporal approach is a feasible option to maintain blood flow in cases of PCA fusiform aneurysms requiring trapping of the P2 segment.

The Extended Lateral Supraorbital Approach and Extradural Anterior Clinoidectomy Through a Frontopterio-Orbital Window: Technical Note and Pilot Surgical Series

BACKGROUND

Lateral approaches to treat anterior cranial fossa lesions have evolved since the first frontotemporal approach described by Dandy in 1918. We describe a less invasive approach to perform extradural anterior clinoidectomy through a lateral supraorbital (LSO) approach for anterior circulation aneurysms and anterolateral skull base lesions.

METHODS

The extended LSO approach involves performing a standard lateral supraorbital craniotomy followed by drilling of the sphenoid wing and lateral wall of the orbit through the frontal bony opening of the LSO approach, without any temporal extension of the craniotomy. This creates a frontopterio-orbital window exposing the periorbita; superior, medial, and anterior aspect of the temporal dura mater; and superior orbital fissure. After unroofing the superior orbital fissure, the meningo-orbital fold is cut, and the temporal dura mater is peeled from the lateral wall of the cavernous sinus to expose the anterior clinoid process allowing a standard opening of the optic canal and anterior clinoidectomy.

RESULTS

The extended LSO approach and extradural anterior clinoidectomy allowed access to 4 sphenoid wing/anterior clinoidal meningiomas, 5 anterior circulation aneurysms, 2 temporomesial lesions, and 1 orbital/cavernous sinus abscess. Postoperatively, 2 patients had transient hemiparesis, 2 patients had transient third nerve palsy, and 1 patient had minimal visual field deterioration. All patients had a modified Rankin Scale score ≤1 at 8-week follow-up.

CONCLUSION

The extended LSO approach opens a new route (frontopterio-orbital window) to perform extradural anterior clinoidectomy safely and increases surgical exposure, angles, and operability of a less invasive keyhole craniotomy (LSO approach) to treat anterior cranial fossa lesions.

Factors Determining Surgical Approaches to Basilar Bifurcation Aneurysms and Its Surgical Outcomes

BACKGROUND:

The basilar bifurcation aneurysm (BBA) is still considered to be one of the most challenging aneurysms for micro- and endovascular surgery. Classic surgical approaches, such as subtemporal, lateral supraorbital (LSO), and modified presigmoid, are still reliable and effective.

OBJECTIVE:

To analyze the clinical and radiological factors that affect the selection of these classic surgical approaches and their outcomes.

METHODS:

A retrospective analysis was conducted on the clinical and radiological data from computed tomographic angiography of BBA that have been clipped in the Department of Neurosurgery of Helsinki University Central Hospital between 2004 and 2014. Statistical analyses were performed using parametric and nonparametric tests where values were considered significant below P = .05.

RESULTS:

One hundred four patients with BBA underwent surgical clipping in our department between 2004 and 2014. Eight patients were excluded from the study because of incomplete preoperative radiological evaluations, leaving 96 patients for further analysis. Multiple aneurysm clipping, mean basilar bifurcation angle, and aneurysm neck distance from posterior clinoid process were shown to be factors that determine the surgical approach. Unfavorable outcome is strongly associated with poor Hunt-Hess grade on admission, distance from aneurysm neck (the posterior clinoid process), thrombosis, and dome size.

CONCLUSION:

Microsurgery for BBA clipping can be performed safely with simple surgical approaches: subtemporal and LSO. There are several factors determining the approach selected. Poor patient outcome in BBA was highly associated with poor preoperative clinical grade and large size of aneurysm dome.

Contralateral Approach to Bilateral Middle Cerebral Artery Aneurysms: Comparative Study, Angiographic Analysis, and Surgical Results

BACKGROUND

Bilateral aneurysms located between the 2 middle cerebral artery (MCA) bifurcations may be approachable through a single unilateral approach.

OBJECTIVE

To identify anatomic parameters based on imaging that would favor a contralateral approach.

METHODS

From January 1998 to December 2013, we retrospectively identified 173 patients with bilateral intracranial aneurysms. Fifty-one patients had bilateral MCA aneurysms. A total of 38 patients underwent a single craniotomy with a contralateral microsurgical approach (group 1 or contralateral group) and 13 patients underwent bilateral craniotomies (group 2 or bilateral group). For both groups, we analyzed aneurysm characteristics, morphology, size, projections, and distance to the contralateral corridor, as well as surgical time, outcome, and postoperative complications.

RESULTS

All aneurysms approached contralaterally were unruptured and without wall calcifications. Of the contralaterally approached aneurysms, 97% were smaller than 14 mm. The median length of the contralateral A1 was 13.2 mm (range: 6-19.8 mm) and the median length of the contralateral M1 was 14.2 mm (range: 4.6-21 mm). The contralateral group had a good postoperative outcome (modified Rankin Scale 0-3) in 80% of ruptured cases and 86% of unruptured cases. The median surgical time was 120 minutes (range: 75-255 minutes), 43% shorter than the bilateral group.

CONCLUSION

The contralateral approach for bilateral MCA aneurysms in selected patients is feasible in experienced hands, with acceptable morbidity and mortality. The contralateral approach requires a meticulous preoperative analysis of the characteristics of the aneurysms to be clipped and of the anatomic constraints of the microsurgical operative corridor.

ABBREVIATIONS

A1, anterior cerebral artery proximal segmentbMCA, bilateral middle cerebral arteryCTA, computed tomographic angiographyHH, Hunt-Hess scaleIA, intracranial aneurysmsICA, internal carotid arteryICAbif, internal carotid artery bifurcationMCA, middle cerebral arteryM1, middle cerebral artery proximal segmentmRS, modified Rankin ScaleSAH, subarachnoid hemorrhage.

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

BACKGROUND

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.

Visualization of luminal thrombosis and mural Iron accumulation in giant aneurysms with Ex vivo 4.7T magnetic resonance imaging

Background:

Better diagnostic tools to identify rupture-prone saccular intracranial aneurysms (sIA) are needed. Inflammation and luminal thrombus associate with degeneration and rupture of the sIA wall. Iron-uptake has been detected in the inflammatory cells of the sIA wall and thrombus is the likely source of this iron. We investigated ex vivo the use of magnetic resonance imaging (MRI) to detect iron accumulation and luminal thrombus in giant sIAs.

Methods:

Giant sIAs (n = 3) were acquired from microsurgical operations, fixed with formalin, embedded in agar and imaged at 4.7T. Samples were sectioned maintaining the orientation of the axial plane of MRI scans, and stained (hematoxylin-eosin and Prussian blue).

Results:

All three giant sIAs showed a degenerated hypocellular wall with both mural and adventitial iron accumulation and displayed different degrees of luminal thrombus formation and thrombus organization. Signal intensity varied within the same sIA wall and associated with iron accumulation in all tested sequences. Wall areas with iron accumulation had significantly lower signal to noise ratio (SNR) compared with areas without iron accumulation (P = 0.002). Fresh and organizing thrombus differed in their MRI presentation and differed in signal intensity of the aneurysm wall (P = 0.027).

Conclusion:

MRI can detect ex vivo the accumulation of iron in giant sIA wall, as well as fresh and organizing luminal thrombus. These features have been previously associated with fragile, rupture-prone aneurysm wall. Further studies of iron accumulation as a marker of rupture-prone aneurysm wall are needed.

High-resolution TOF MR angiography at 4.7 Tesla for volumetric and morphologic evaluation of coiled aneurysm neck remnants in a rat model

BACKGROUND

Detection of morphologic and volumetric changes in aneurysm necks is important when evaluating the effects of endovascular devices for aneurysm occlusion.

PURPOSE

To optimize high-resolution 3D-TOF MRA at 4.7 T in order to achieve the best aneurysm-to-background contrast in experimental rat aneurysms, and to quantify the volume of the aneurysm neck by imaging.

MATERIAL AND METHODS

Saccular aneurysms in the abdominal aorta of rats were coiled with platinum coils. Tissue relaxation times were measured, and used in a mathematical simulation. To optimize 3D-TOF angiography, imaging parameters were varied within the range obtained from the simulations. Tissue contrast and contrast-to-noise ratio were measured from MR images. TOF images were compared to conventional spin echo and gradient echo images and to endoscopic and histological analyses.

RESULTS

Parameters yielding the best aneurysm-to-background contrast and contrast-to-noise ratio were determined. The agreement between the results from in vivo imaging and simulation was good. The optimized 3D-TOF MRA sequence (TR/TE/FA = 60 ms/6.6 ms/20°) had an isotropic voxel size of 117 µm, which enabled measurement of the aneurysm neck volume.

CONCLUSION

High-resolution 3D-TOF angiography enables non-invasive quantification of changes in neck remnants of endovascularly coiled experimental aneurysms. In this model innovations like bioactive coils can be accurately tested for their efficacy for aneurysm occlusion.

Microsurgical removal of Onyx HD-500 from an aneurysm for relief of brainstem compression. Case report

The authors report the successful removal of Onyx HD-500 from an aneurysm sac by means of ultrasonic aspiration. This 46-year-old woman presented with progressive spasms of her left arm and leg due to mass effect and compression on the right cerebral peduncle 5 years after endovascular treatment of an unruptured giant posterior communicating artery aneurysm with Onyx HD-500. No filling of the aneurysm was detected on angiography. The patient underwent a right pterional craniotomy and the aneurysm was opened to remove the Onyx mass. However, contrary to expectations, the aneurysm was still patent, filling with blood between the Onyx mass and the aneurysm wall. Under temporary clipping of the carotid artery, the Onyx mass within the aneurysm was removed in a piecemeal fashion using an ultrasonic aspirator and the aneurysm was then successfully clipped. The patient experienced significant improvement of the spasm after surgery. Angiography showed complete occlusion of the posterior communicating artery aneurysm. It is rarely necessary to remove embolization material such as Onyx HD-500, and little is known about the most appropriate surgical technique. This case report demonstrates that removal can be safely accomplished by means of ultrasonic aspiration.

Relationship of the Met allele of the brain-derived neurotrophic factor Val66Met polymorphism to memory after aneurysmal subarachnoid hemorrhage

OBJECTIVE

The brain-derived neurotrophic factor (BDNF) Val66Met polymorphism has been shown to be related to variability in episodic memory. We studied whether the Met allele is associated with poor learning and memory in survivors of aneurysmal subarachnoid hemorrhage (SAH).

METHODS

Ninety-six patients were examined with a neuropsychological test battery approximately 1 year after SAH. Their deoxyribonucleic acid samples were genotyped for the BDNF Val66Met polymorphism. The Met carriers were compared to the Val/Val homozygous patients on the test performances.

RESULTS

In the total sample, there was no difference between the genotype groups. However, among the patients with no cerebral infarction, the Met carriers had inferior learning and memory performance than the Val/Val homozygotes, but the groups did not differ on the nonmemory test performances. The patients with left and bilateral infarctions had deficits in verbal memory, which may have concealed the effect of the BDNF Val66Met polymorphism on memory in the total sample.

CONCLUSION

As a whole, the BDNF Val66Met polymorphism was not associated with learning and memory performance in patients recovering from SAH. However, the Met allele might predict poor memory function among patients with SAH not complicated by a cerebral infarction. These findings support earlier reports of an association between the Met allele and low memory performance. Longitudinal studies comparing functional recovery from SAH between Met and Val/Val patients without cerebral infarctions are warranted.

Long-term excess mortality in 623 patients with brain arteriovenous malformations

OBJECTIVE

Long-term follow-up studies in patients with brain arteriovenous malformations (AVM) have been scarce and without proper statistical estimates of mortality. We performed a retrospective survival study in 623 consecutive patients with AVMs admitted to the Department of Neurosurgery in Helsinki University Hospital between 1951 and 2005.

METHODS

Patients were followed from admission until death or the end of 2005. Patient survival was estimated using the relative survival ratio, which provides a measure of the excess mortality experienced by the patients compared with the general Finnish population matched by age, sex, and calendar time.

RESULTS

Median follow-up was 11.9 years, and total follow-up was 10,165 person-years. Treatment was conservative in 155 patients. Total AVM occlusion was attained in 356 patients, and partial occlusion was obtained in 94 patients. Overall, 206 deaths were observed. Of these, 100 were related to AVMs. Diagnosis of AVM was associated with significant long-term excess mortality, with cumulative relative survival ratios of 0.85 (95% confidence interval, 0.81-0.88) and 0.69 (95% confidence interval, 0.62-0.75) at 10 and 30 years after admission, respectively. Men had higher excess mortality than women. The excess in mortality was highest in conservatively treated patients, intermediate in patients with partially occluded AVMs, and lowest in those with totally occluded AVMs. The subgroup with the best outcome consisted of those with totally occluded unruptured AVMs, which did not demonstrate excess mortality after the first year.

CONCLUSION

AVMs are associated with long-term excess mortality that may be reduced by active, even partial, treatment. Male patients have a higher excess mortality rate than female patients.

Vascular clamp-assisted clipping of thick-walled giant aneurysms

OBJECTIVE

The prognosis of giant aneurysms remains poor despite recent advances in microneurosurgery. Thick-walled and partially calcified giant aneurysms with an atheromatic base are difficult to clip safely. Special techniques allowing reshaping of the base and ensuring the stability of clips are often needed. We present our experience with direct clipping of thick-walled giant aneurysms with the aid of the DeBakey cardiovascular clamp (Aesculap, Tuttlingen, Germany).

METHODS

Eighty-two patients with a giant aneurysm (>/=25 mm) were treated actively at the Department of Neurosurgery, Helsinki University Central Hospital, Helsinki, Finland, between 1997 and 2007. The vascular clamp technique was used in 8 of 50 patients in whom direct clipping was performed. The remaining patients were treated with bypass and trapping, trapping only, proximal occlusion, coiling, or explorative surgery.

RESULTS

The vascular clamp (DeBakey in 5 cases, Crile forceps [Medicon Medizin-Technik, Tuttlingen, Germany] in 2 cases, and Halsted-Mosquito forceps [Medicon Medizin-Technik, Tuttlingen, Germany] in 1 case) was used in 7 saccular middle cerebral artery aneurysms and 1 fusiform basilar bifurcation aneurysm. Two patients had postoperative infarctions, 1 attributable to occlusion of perforators by a clip and the other caused by clips sliding down the calcified base, occluding a major branch. Six patients had no neurological sequelae, 1 patient had transient upper limb paresis, and the patient with the occluded major branch died.

CONCLUSION

The DeBakey vascular clamp is helpful in assisting direct clipping of thick-walled giant aneurysms with a partially calcified atheromatic base. Some practical features of this instrument require further refinement.

THIRD VENTRICULOSTOMY THROUGH THE FENESTRATED LAMINA TERMINALIS DURING MICRONEUROSURGICAL CLIPPING OF INTRACRANIAL ANEURYSMS

OBJECTIVE

Fenestration of the lamina terminalis (LT) is an alternative means of cerebrospinal fluid (CSF) drainage during acute or emergency surgery of ruptured intracranial aneurysms in patients with high-grade subarachnoid hemorrhage. External ventricular drainage allows drainage of CSF and also measurement of intracranial pressure after the surgery. Catheterization of the third ventricle via the fenestrated LT after clipping the aneurysm is an alternative to conventional ventriculostomies. This method has been used by the senior author (JAH) since 2001. The authors describe their experience with this technique, which can be used safely in selected cases of high-grade subarachnoid hemorrhage.

METHODS

Seventy-eight patients with aneurysmal subarachnoid hemorrhage underwent third ventriculostomy via the LT between March 2001 and December 2005. Clinical and radiological data of these consecutive patients were retrospectively reviewed.

RESULTS

There were no procedure-related complications. Eight patients (10%) later required a conventional ventriculostomy, 7 because of catheter occlusion and 1 because of catheter displacement. In 7 patients (9%), a positive CSF culture was found.

CONCLUSION

Ventriculostomy via the fenestrated LT performed during aneurysm surgery is a practical way for later CSF removal and intracranial pressure monitoring. The catheter can be applied via the same craniotomy without the need for an additional intervention. No procedure-related complications were observed in the present series. This technique can be suggested as a safe alternative to a classical ventriculostomy.

Dizygotic twins with a colloid cyst of the third ventricle: case report

OBJECTIVE AND IMPORTANCE

Colloid cysts of the third ventricle are rare benign tumors of endodermal origin accounting for 1% of all intracranial tumors. Interestingly, a few familial cases have been reported previously. We present the first case of dizygotic twins with a symptomatic colloid cyst of the third ventricle.

CLINICAL PRESENTATION

A 10-year-old boy was admitted to a local hospital in 1993 because of severe progressive headache. Computed tomographic and magnetic resonance imaging scans revealed acute obstructive hydrocephalus attributable to a third ventricular colloid cyst, which was removed after emergent ventricular drainage. Fourteen years later, a nonidentical twin brother complained of continuous headache with nausea and vomiting. A magnetic resonance imaging scan showed obstructive hydrocephalus and a third ventricle colloid cyst, which was removed by use of the transcallosal approach.

INTERVENTION

Both twins underwent complete removal of the cyst by the interhemispheric transcallosal approach without postoperative complications.

CONCLUSION

On the basis of a literature review, 2 cases of colloid cysts of the third ventricle in monozygotic twins and a few familial cases have been reported. Our case is the first in dizygotic twin brothers. These findings suggest that the prevalence of colloid cyst may be higher in twins than in the general population. We believe that the presence of this lesion in a twin necessitates magnetic resonance imaging of the other twin, and a clinical follow-up would be recommended in all other first-degree relatives.

NATURAL HISTORY OF BRAIN ARTERIOVENOUS MALFORMATIONS

OBJECTIVE

Long-term follow-up studies in patients with brain arteriovenous malformations (AVM) have yielded contradictory results regarding both risk factors for rupture and annual rupture rate. We performed a long-term follow-up study in an unselected, consecutive patient population with AVMs admitted to the Department of Neurosurgery at Helsinki University Central Hospital between 1942 and 2005.

METHODS

Patients with untreated AVMs were followed from admission until death, occurrence of AVM rupture, initiation of treatment, or until the end of 2005. Patients with at least 1 month of follow-up were included in further analysis. Annual and cumulative incidence rates of AVM rupture as well as several potential risk factors for rupture were analyzed using Kaplan-Meier life table analyses and Cox proportional hazards regression models.

RESULTS

We identified 238 patients with a mean follow-up period of 13.5 years (range, 1 month–53.1 years). The average annual risk of hemorrhage from AVMs was 2.4%. The risk was highest during the first 5 years after diagnosis, decreasing thereafter. Risk factors predicting subsequent AVM hemorrhage in univariate analysis were young age, previous rupture, deep and infratentorial locations, and exclusively deep venous drainage. Previous rupture, large AVM size, and infratentorial and deep locations were independent risk factors according to multivariate models.

CONCLUSION

According to this long-term follow-up study, AVMs with previous rupture and large size, as well as with infratentorial and deep locations have the highest risk of subsequent hemorrhage. This risk is highest during the first few years after diagnosis but remains significant for decades.

Distal anterior cerebral artery aneurysms: treatment and outcome analysis of 501 patients

OBJECTIVE

This study presents the combined experience of two Finnish neurosurgical centers in the treatment of 501 consecutive patients with distal anterior cerebral artery (DACA) aneurysms. Our aim was to compare treatment outcomes of these lesions with intracranial aneurysms in general and to identify factors predicting the outcome.

METHODS

We analyzed the clinical and radiological data of all 501 patients and focused on the 427 patients treated between 1980 and 2005, the era of microsurgery and computed tomographic imaging. No patients were lost to follow-up. We compared treatment and outcome of ruptured DACA aneurysms (n = 277) with all consecutive ruptured aneurysms from the Kuopio Cerebral Aneurysm Database (n = 2243) and used multivariate analysis to identify factors predicting 1-year outcome.

RESULTS

DACA aneurysms accounted for 6% of all intracranial aneurysms. They were smaller (median, 6 versus 8 mm), more frequently associated with multiple aneurysms (35 versus 18%), and presented more often with intracerebral hematomas (53 versus 26%) than ruptured aneurysms in general. Their microsurgical treatment showed the same complication rates (treatment morbidity, 15%; treatment mortality, 0.4%) as for other ruptured aneurysms. At 1 year after subarachnoid hemorrhage, they had similar favorable outcome (Glasgow Coma Scale score >or=4) as other ruptured aneurysms (74 versus 69%), but their mortality rate was lower (13 versus 24%). Factors predicting unfavorable outcome for ruptured DACA aneurysms were advanced age, Hunt and Hess grade greater than or equal to III, rebleeding before treatment, intracerebral hematoma, intraventricular hemorrhage, and severe preoperative hydrocephalus.

CONCLUSION

Despite their specific features, with modern treatment methods, ruptured DACA aneurysms have the same favorable outcome and lower mortality at 1 year as ruptured aneurysms in general.

Taming the Cavernous Sinus: Technique of Hemostasis Using Fibrin Glue

Objective:

Improved understanding of the microsurgical anatomy of the cranial base region has made surgery in and through the cavernous sinus safer. However, continuous venous oozing that occurs during cavernous sinus surgery can cause significant blood loss and poor visualization. We describe a technique that will help minimize cavernous sinus bleeding and improve the safety of the surgical steps.

Methods:

The lateral wall of the cavernous sinus is exposed. Cavernous sinus access windows between the V1 and V2 branches of the trigeminal nerve and posterior to the clinoidal internal carotid artery are used to inject fibrin glue into the different cavernous sinus compartments. Postoperative follow-up cerebral angiography in basilar apex aneurysms clipped using the transcavernous approach were evaluated for cavernous sinus patency during the venous phase.

Results:

Fibrin glue injection between V1 and V2 obliterated the lateral cavernous sinus compartment. Fibrin glue injection posterior to the clinoidal segment of the internal carotid artery obliterated the medial compartment of the cavernous sinus. These steps were used in 217 surgical procedures (95 benign and 9 malignant neoplastic lesions; 113 aneurysms). There were no significant clinical side effects. Follow-up angiographic controls of basilar aneurysms operated on via the transcavernous approach consistently showed the reestablishment of flow within the cavernous sinus as early as 2 to 3 months postoperatively.

Conclusion:

Presently, the use of hemostatic agents and the better understanding of the microsurgical anatomy of the cranial base and cavernous sinus enable us to tame the cavernous sinus and operate in and around it with a high degree of safety.

Magnetic resonance angiographic screening for asymptomatic intracranial aneurysms: the problem of false negatives: technical case report

To emphasize the limitations of magnetic resonance angiographic screening for intracranial aneurysms, we present the case of a patient with a false-negative screening result, unfortunately advancing to rupture of the aneurysm. An asymptomatic woman underwent magnetic resonance angiographic screening in an investigational setting. Three years later, she had an onset of sudden headache, after which her condition rapidly deteriorated. Severe subarachnoid hemorrhage and an intracerebral hematoma were diagnosed. Conventional angiography detected a small ruptured middle cerebral artery trifurcation aneurysm and two very small aneurysms. There are still limitations in the ability of magnetic resonance angiography to detect small or very small aneurysms. Even small-probability findings should always be confirmed or excluded by conventional angiography.

Intracranial aneurysms: MR angiographic screening in 400 asymptomatic individuals with increased familial risk

PURPOSE

To evaluate the accuracy and limitations of magnetic resonance (MR) angiographic screening for incidental intracranial aneurysms (IAs) in healthy individuals with a family history of IA.

MATERIALS AND METHODS

Four hundred asymptomatic individuals in 68 families with a history of aneurysmal subarachnoid hemorrhage underwent MR angiography. Six families also had a history of polycystic kidney disease. A multislab, three-dimensional, time-of-flight sequence was used. Conventional angiography was performed to confirm positive MR angiographic findings.

RESULTS

IAs were detected with MR angiography in 37 individuals, 32 of whom underwent conventional angiography. Intraobserver consistency was excellent (kappa = 0.96), and interobserver reproducibility was good to excellent (kappa = 0.59-0.82). Both techniques showed similar results in the evaluation of size, localization, and orientation of aneurysms and visibility of the aneurysm neck.

CONCLUSION

MR angiography is an accurate and feasible method of noninvasive screening for IAs in individuals at high risk. Conventional angiography is still necessary before operative treatment.

Contribution of non-neurologic disturbances in acute physiology to the prediction of intensive care outcome after head injury or non-traumatic intracranial haemorrhage

OBJECTIVE

To study the additional contribution of non-neurologic disturbances in acute physiology and chronic health to the prediction of intensive care outcome in patients with head injury or non-traumatic intracranial haemorrhage.

DESIGN

A nationwide study in Finland with prospectively collected data on all adult patients admitted to intensive care after head trauma or non-traumatic intracranial haemorrhage during a 14-month period. Two-thirds of the patients were randomly selected to derive predictive models, and the remaining one third constituted the validation sample.

SETTING

A total of 25 medical and surgical ICUs in Finland (13 in tertiary referral centers).

PATIENTS

901 consecutive adult patients with head injury or non-traumatic intracranial haemorrhage.

MEASUREMENTS AND RESULTS

Variables of the APACHE II including Glasgow Coma Score were collected at the time of ICU admission. Two predictive models were created to explain hospital mortality. The addition of variables describing acute physiology to a predictive model consisting of Glasgow Coma Score, age, diagnosis of head injury and the type of ICU admission did not increase its performance in discriminating between survivors and nonsurvivors, but the calibration accuracy of the predictive model especially at the high ranges of risk was improved.

CONCLUSIONS

The non-neurologic disturbances in acute physiology have prognostic significance in the prediction of intensive care outcome in patients with head injury or non-traumatic intracerebral haemorrhage. The created predictive model may supplement clinical judgement of this patient group.

Quantitative metabolite patterns of human brain tumors: detection by 1H NMR spectroscopy in vivo and in vitro

OBJECTIVE

The aim of the present study was to investigate quantitative metabolite patterns in human brain tumors by 1H nuclear MR spectroscopy (1H MRS).

MATERIALS AND METHODS

Single voxel 1H MRS was used in studying metabolites in 23 primary brain tumors in vivo. The T2 relaxation times and saturation factors were determined for N-acetylaspartate (NAA), total creatine (Cr), choline-containing compounds (Cho), and water, which was used as an internal standard in computations of metabolite concentrations in vivo. Metabolites in biopsy specimens from 75 tumors were quantified by means of 1H MRS in vitro.

RESULTS

The NAA concentrations were lower in brain tumors than in normal tissue in vitro and in vivo, irrespective of the histological type. The NAA was some threefold higher in vivo than in vitro, which could be due to partial volume effect and/or contributions from other metabolites to the peak at 2.02 ppm in vivo. Ratios of Cho to Cr concentrations were elevated in tumors relative to normal brain in vivo. Absolute Cho was some 50% higher in both benign astrocytomas and oligodendrogliomas in vivo than in normal brain. However, Cho concentration in vitro was significantly higher only in pituitary adenomas than in healthy white matter. Total creatine was approximately 50% lower in malignant astrocytomas and meningiomas than in normal brain.

CONCLUSION

It is concluded that absolute concentrations of metabolites in vivo yield a different picture of tumor metabolites than that derived from uncorrected metabolite ratios.

Early surgery for ruptured vertebrobasilar aneurysms

The authors present a series of 1767 patients with aneurysms of the vertebrobasilar circulation, most of whom were operated on 14 days or more following their last subarachnoid hemorrhage (SAH). Since 1970, 206 patients with vertebrobasilar aneurysms have been surgically treated within 7 days after their last SAH (day of SAH = Day 0). Of patients with a good preoperative grade (Botterell Grade 1 or 2), a good or excellent outcome was obtained in 80% during the first postsurgical month, irrespective of the timing of surgery. All except one of the Grade 5 patients died, and 70% of the Grade 4 patients were significantly disabled or dead. The overall operative mortality rate was the same whether surgery took place in the 1st week after SAH or was delayed. The frequency of rupture of the aneurysm during early surgery was not higher than during late surgery. Thirteen percent of patients developed a delayed ischemic neurological deficit as a consequence of reactive arterial narrowing (vasospasm). The authors recommend early surgery for patients with a good preoperative grade, whose aneurysm does not present a particular technical difficulty because of size, configuration, or location, and occasionally in patients whose lives appear to be in jeopardy because of recurrent hemorrhage.

De novo aneurysms: special multiple intracranial aneurysms

Very few patients develop completely new intracranial aneurysms during long-term follow-up after successfully treated subarachnoid hemorrhages. Aneurysms appearing after therapeutic ligation of proximal major vessels or failed surgery and the growth of previously noticed infundibular widenings or small aneurysms must be excluded to find true de novo aneurysms. Twenty-nine true cases of de novo aneurysms were reported in the literature, and 13 additional cases of our own are described. The incidence of de novo aneurysm formation and rupture is 63 per 100,000 per year in patients known to have a subarachnoid hemorrhage. Young patients could benefit from long-term neuroradiological follow-up.

One-year outcome in early aneurysm surgery: prediction of outcome

Predictors of one-year outcome were studied in patients treated for ruptured intracranial aneurysm. A total of 929 patients, who were treated conservatively or surgically, and 839 patients as a part of this population who were surgically treated, were randomly divided into two groups in order to create predictive models by logistic regression and to validate them. The models were derived from two-thirds of these two patient groups and the remaining one-thirds were used for validation. The pre-operative variables of both conservatively and surgically treated patients were studied by Model A. The pre-operative Grade (Hunt and Hess), age, and the presence of vasospasm on angiography were the three most important predictors of the one-year outcome (Glasgow Outcome Scale 1-2/3-5). Model B consisted of pre- and per-operative, and Model C pre-, per-, and post-operative variables collected from the surgically treated group. The pre-operative Grade, ligation of a major vessel and age were the three most powerful determinants of outcome in Model B. In Model C high Grade, post-operative CT-hypodensities and ligation of a major vessel were most closely associated with poor outcome. Model A, based on pre-operative data, most accurately predicted good outcome. All the 59 patients in the validation sample (n = 310) who were predicted to have a less than 5% probability of poor outcome had a favourable outcome (positive and negative predictive value 100%). Model C determined that 22 of 280 patients would have a more than 80% probability of poor outcome.(ABSTRACT TRUNCATED AT 250 WORDS)