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.

The orbitozygomatic stich: A technical modification of the lateral supraorbital approach.

BACKGROUND: The lateral supraorbital approach (LSO) provides access to a variety of pathologies including anterior and some posterior circulation aneurysms, sellar and suprasellar lesions, and anterior fossa tumors. Technical modifications of LSO improve the surgical exposure of the skull base. METHODS: We retrospectively analyzed 73 consecutive patients treated by the senior author (Juha A. Hernesniemi), at the Department of Neurosurgery, Helsinki University Hospital in Helsinki, Finland from May 2013 to October 2013. This study cohort underwent a modified LSO to access anterior circulation aneurysms, sellar and suprasellar tumors, and anterior fossa tumors. The studied population comprised 30 men and 43 women, with a mean age at treatment of 54 years (9-83 years). RESULTS: LSO was successfully used to access anterior circulation aneurysms in 59 (81%) patients, 10 (14%) patients with anterior cranial fossa tumors, and 4 (5%) patients with suprasellar tumors. The skull base drilling provided a mean of 6.8 mm (1.7-22 mm) in increased exposure. CONCLUSION: LSO provides adequate access to vascular and neoplastic lesions of the anterior cranial fossa, by drilling approximately 6.8 mm (1.7-22 mm) of the lateral orbital wall and sphenoid wing. This enhances surgical exposure and trajectory. An additional trick while performing an LSO is to place a single or multiple stiches (orbitozygomatic stich) at the base of the dura once opened, eliminating the dead space between the dura and anterior skull base.

Posterior Cerebral Artery Aneurysms: Treatment and Outcome Analysis in 121 Patients.

OBJECTIVE: Aneurysms of the posterior cerebral artery (PCA) are uncommon. Because of their low incidence, only 5 series with more than 30 patient cases have been reported. The treatment of PCA aneurysms is challenging because of the high frequency of fusiform aneurysms and closeness to important neuroanatomic structures. METHODS: A total of 121 patients with 135 PCA aneurysms were reviewed. The clinical and radiologic data, treatment strategies, and 1-year outcomes were analyzed. Patients with giant aneurysms, associated aneurysms, and aneurysms on arteriovenous malformation-feeding PCAs were considered as complex cases. Outcomes were categorized into 3 groups: good (modified Rankin Scale [mRS], score 0-1), moderate (mRS score, 2-4), and poor (mRS score, 5-6). RESULTS: There were 52 ruptured (39%) and 83 unruptured (61%) PCA aneurysms in 121 patients, with the following distribution: P1 (n = 53), P1/2 (n = 39), P2 (n = 28), and P3 (n = 15). The incidence of fusiform PCA aneurysms was high (24%). Microsurgical treatment was applied to 63 aneurysms and endovascular treatment to 19 aneurysms; 55 aneurysms were treated conservatively. The following treatment results were achieved: for patients with unruptured PCA aneurysms, n = 19; 12 good outcomes, 63%; 6 moderate, 31%; 1 poor, 1%; for patients with ruptured PCA aneurysms, n = 27; 10 good, 37%; 9 moderate, 33%; 8 poor, 30%; and for patients with complex neurovascular diseases and PCA aneurysms, n = 96; 42 good, 43%; 40 moderate, 42%; 14 poor, 15%. CONCLUSIONS: Aneurysms of the PCA are infrequent and often associated with other vascular diseases. Microsurgery and endovascular treatment are effective for the occlusion of PCA aneurysms. The preservation or reconstruction of the parent vessel is crucial for favorable treatment outcomes.

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.

Transient Cardiac Arrest Induced by Adenosine: A Tool for Contralateral Clipping of Internal Carotid Artery-Ophthalmic Segment Aneurysms.

BACKGROUND: The disadvantages of a contralateral approach (CA) include deep and narrow surgical corridors and inconsistent ability to achieve proximal control of the supraclinoid internal carotid artery (ICA). However, a CA remains as a microsurgical option for selected ICA-ophthalmic (opht) segment aneurysms. OBJECTIVE: To describe transient cardiac arrest induced by adenosine as an alternative tool to obtain proximal vascular control and soften the aneurysm sac in selected patients while performing a CA. METHODS: From January 1998 to December 2013, we retrospectively identified 30 patients with ICA-opht segment aneurysms treated through a CA. Of those, 8 patients received an intravenous bolus of adenosine to induce transient cardiac arrest for softening of the aneurysm sac. We reviewed preoperative clinical status, characteristics of the contralateral aneurysm, adenosine doses, asystole time, recovery of normal circulation, outcome, and complications. RESULTS: No preoperative cardiac or pulmonary pathologies were found in the study population. All contralateral ICA-opht segment aneurysms were unruptured, small, and saccular in shape. Transient cardiac arrest was induced because it was impossible to apply a temporary clip on the parent contralateral supraclinoid ICA. The median dose of adenosine was 22.5 mg (range, 5-50 mg) and the asystole time ranged from 20 to 40 seconds. All patients (n = 8) had good postoperative outcomes. No brain infarction or cardiac complications appeared postoperatively. CONCLUSIONS: In selected patients, transient cardiac arrest induced by adenosine during a contralateral approach allows a brief flow arrest and softening of the aneurysm for safer exposure and clipping.

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.

Subtemporal approach to posterior cerebral artery aneurysms.

OBJECTIVE: Aneurysms of the posterior cerebral artery (PCA) are rare, and therefore the individual and institutional experience of their microsurgical management is usually limited. In the present article, we describe our experience with the subtemporal approach to aneurysms arising from the PCA. METHODS: We reviewed 34 patients diagnosed with 37 PCA aneurysms, all microsurgically managed using the subtemporal approach between 1980 and 2012 at 2 Finnish neurosurgical centers (Helsinki and Kuopio). The following procedures were applied using the subtemporal approach: neck clipping (n = 24); proximal occlusion (n = 7); trapping (n = 2); wrapping (n = 1); aneurysmoraphy (n = 1); bypass bridging/trapping (n = 1); and a complex excimer laser-assisted nonocclusive anastomosis procedure (n = 1). RESULTS: Of these 34 patients, 16 presented with acute subarachnoid hemorrhage as a result of PCA aneurysm rupture, and 11 of the 16 had good outcome (modified Rankin scale 0-2) at 3 months The remaining 18 patients were treated microsurgically for incidentally diagnosed unruptured aneurysms, and 14 of the 18 had a good outcome. The most common serious complication in this series was an ipsilateral PCA infarction (12/34; 35%), mostly after proximal occlusion (n = 7) and/or trapping (n = 2). CONCLUSIONS: The subtemporal approach is a suitable approach to aneurysms of the segments P1, P1-P2 junction, and P2, as well as the anterior P3 segment of the PCA. Using the subtemporal approach, the cerebrospinal fluid is released before retraction is necessary to prevent temporal lobe injury. The subtemporal approach can provide enough space for revascularization procedures. The most encountered complications were not related to the subtemporal approach but to the specific nature of PCA aneurysms.

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.

Optimization of high-resolution USPIO magnetic resonance imaging at 4.7 T using novel phantom with minimal structural interference.

PURPOSE: To characterize the effect of ultrasmall superparamagnetic iron oxides (USPIOs) on magnetic resonance imaging (MRI) signal at 4.7 T, and to find the highest sensitivity pulse sequence for high-resolution USPIO MRI. MATERIALS AND METHODS: A novel phantom was constructed for optimization of sequence parameters for neuroradiological MR applications, and a wide range of dilutions of the USPIO ferumoxtran-10 was imaged using T(2)/T(1)-, T(1)-, T(2)-, T* (2)-, and PD-weighted sequences. The effect of varying sequence parameters was investigated using phantom measurements and simulations. RESULTS: The relaxivities r(1), r(2), and r*(2) of ferumoxtran-10 at 4.7 T (21°C) were 5.1, 82.2, and 148.4 mmol(-1) L s(-1), respectively. Gradient echo sequences produced superior susceptibility artifacts at high concentrations; susceptibility artifacts were seen down to a concentration of 137 nmol Fe/mL. A concentration of 17.5 µmol Fe/mL caused a signal void independently of sequence and parameters, and at concentrations ≤273 nmol Fe/mL no signal void was caused. Signal enhancement on T(1)-weighted imaging was seen only at concentrations 137-547 nmol Fe/mL. For the same effective echo time T(2)-weighted rapid acquisition with relaxation enhancement (RARE) yielded significantly higher contrast-to-noise ratio with RARE factor 16 than with RARE factor 8. CONCLUSION: At nanomolar concentrations of USPIO, steady-state free precession offers an alternative to T(2)- and T*(2)-weighted sequences. Optimum parameters depend highly on USPIO concentration.

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.

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: an alternative to conventional ventriculostomy.

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.

Occlusion of neck remnant in experimental rat aneurysms after treatment with platinum- or polyglycolic-polylactic acid-coated coils.

BACKGROUND: Neck remnants and aneurysm recurrences are marked limitations of endovascular treatment of cerebral artery aneurysms. We compared the evolution of neck remnants of experimental arterial rat aneurysms after treatment with either platinum- or PGLA-coated coils. METHODS: We created 20 standard-size aneurysms in the abdominal aortas of male Wistar rats. Aneurysms were embolized with either PGLA-coated coils or platinum coils, with care taken to leave a neck remnant. Neck remnant size and shape was closely monitored to detect progressive enlargement or occlusion. Using a 4.7 T MR scanner, we acquired high-resolution MR images 6 times during the 4-week follow-up. For quantitative measurements, we used a high-resolution 3D-TOF angiography sequence. Results were verified by endoscopy and histology. RESULTS: Aneurysms treated with PGLA coils showed, on average, a 12.9% reduction of neck remnant size (P = .044) and significant disappearance of dog ears, the blood-filled spaces between coils and aneurysm wall. The aneurysms treated with platinum coils lacked these changes. In endoscopy, neointima was found to cover both PGLA and platinum coils but was more often incomplete or translucent in the platinum group. In histology, thrombus organization and inflammatory cell infiltration were higher with PGLA. CONCLUSION: Use of PGLA-coated coils was followed by a moderate progressive reduction of the neck remnant size and a better angiographic outcome, seen as disappearance of dog ears during follow-up. The rat model proved to be suitable for comparison of different coil types.

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.