Riku Kivisaari

Routine cerebral angiography after surgery for saccular aneurysms: is it worth it?

OBJECTIVE: The objective of this study was to determine whether an angiographically proven rate of saccular intracranial aneurysm occlusion after surgical clipping suggests that postoperative angiography should continue to be used routinely or should be supplanted by intraoperative angiography. These data also should establish a basis for comparing surgery with new endovascular methods of treatment. METHODS: During a 3.5-year period, a consecutive series of 622 patients (955 aneurysms, 808 of which were surgically clipped) who underwent postoperative angiography were studied retrospectively. This series comprised 493 ruptured and 315 unruptured aneurysms. RESULTS: Complete aneurysm closure was achieved in 88% of aneurysms, a neck remnant was discovered in 9%, and a fundus remnant was revealed in 3%. Of 493 ruptured aneurysms, 86% were completely occluded. Of 315 unruptured aneurysms, 91% were completely occluded. The results for clipping of complex aneurysms, i.e., posterior circulation or large to giant aneurysms, were significantly inferior to those for small and anterior circulation aneurysms. In one-third of the large and giant aneurysms, a part of the base was left intentionally because of calcifications or strong wall or to prevent occlusion of any branches. In the series, a significant 5% complication rate of major vessel occlusion was detected. CONCLUSION: Our retrospective analysis revealed that ruptured, posterior circulation, and large/giant aneurysms are more prone to incomplete clipping. Therefore, these aneurysms require postoperative if not intraoperative evaluation with angiography. Many clippings of anterior circulation aneurysms experience unexpected failures, which suggests that intraoperative angiography could be beneficial. This series, which has no selection bias, can be used as a basis to compare the results of other series reporting surgical or endovascular treatment.

Anatomic risk factors for middle cerebral artery aneurysm rupture: computed tomography angiography study of 1009 consecutive patients.

BACKGROUND In a variety of surgical specialties, simulation-based technologies play an important role in resident training. The Congress of Neurological Surgeons (CNS) established an initiative to enhance neurosurgical training by developing a simulation-based curriculum to complement standard didactic and clinical learning. OBJECTIVE To enhance resident education in the management of traumatic brain injury by the use of simulation-based training. METHODS A course-based neurosurgical simulation curriculum was developed and offered at the 2012 CNS annual meeting. Within this curriculum, a trauma module was developed to teach skills necessary in the management of traumatic brain injury, including the performance of craniotomy for trauma. Didactic and simulator-based instruction were incorporated into the course. Written and practical pre- and posttests, as well as questionnaires, were used to assess the improvement in skill level and to validate the simulator as a teaching tool. RESULTS Fourteen trainees participated in the didactic section of the trauma module. Average performance improved significantly in written scores from pretest (75%) to posttest (87.5%, P < .05). Eight participants completed the trauma craniotomy simulator. Incision planning, burr hole placement (P < .02), and craniotomy size (P < .05) improved significantly. Junior residents (postgraduate years 1-3) demonstrated the most improvement during the course. CONCLUSION The CNS simulation trauma module provides a complementary method for residents to acquire necessary skills in the management of traumatic brain injury. Preliminary data indicate improvement in didactic and hands-on knowledge after training. Additional data are needed to confirm the validity of the simulator.BACKGROUND The middle cerebral artery (MCA) is the most frequent location for unruptured intracranial aneurysms. Controversy remains as to which unruptured MCA aneurysms should be treated prophylactically. OBJECTIVE To identify independent topographical and morphological variables that could predict increased rupture risk of MCA aneurysms. METHODS A retrospective analysis of computed tomography angiography data of 1009 consecutive patients with 1309 MCA aneurysms, referred between 2000 and 2009 to Helsinki University Hospital, was carried out. Morphological and topographical parameters examined for MCA aneurysms comprised aneurysm wall regularity, size, neck width, aspect ratio, bottleneck factor, height-width ratio, location along the MCA, side, distance from the internal carotid artery bifurcation, and dome projection in axial and coronal computed tomography angiography views. Univariate and multivariate logistic regression analyses were performed to determine independent risk factors for rupture. RESULTS Of the 1309 MCA aneurysms, 69% were unruptured and 31% were ruptured. Most unruptured MCA aneurysms were smaller than 7 mm (78%), with a smooth wall (80%) and a height-width ratio of 1 (47%) and were located at the main bifurcation (57%). Ruptured MCA aneurysms, mostly 7 to 14 mm in size (55%), had an irregular wall (78%) and a height-width ratio greater than 1 (72%) and were located at the main bifurcation (77%). Thirty-eight percent of MCA bifurcation aneurysms, 74% of large aneurysms, 64% of aneurysms with an irregular wall, and 49% of aneurysms with a height-width ratio greater than 1 were ruptured. CONCLUSION Location at the main MCA bifurcation, wall irregularity, and less spherical geometry were independently associated with rupture of MCA aneurysms with a correlation with aneurysm size. artery.

Long-term outcome of 114 children with cerebral aneurysms

OBJECT Population-based data on pediatric patients with aneurysms are limited. The aim of this study is to clarify the characteristics and long-term outcomes of pediatric patients with aneurysms. METHODS All pediatric patients (≤ 18 years old) with aneurysms among the 8996 aneurysm patients treated at the Department of Neurosurgery in Helsinki from 1937 to 2009 were followed from admission to the end of 2010. RESULTS There were 114 pediatric patients with 130 total aneurysms during the study period. The mean patient age was 14.5 years (range 3 months to 18 years). The male:female ratio was 3:2. Eighty-nine patients (78%) presented with subarachnoid hemorrhage. The majority of the aneurysms (116 [89%]) were in the anterior circulation, and the most common location was the internal carotid artery bifurcation (36 [28%]). The average aneurysm diameter was 11 mm (range 2-55 mm) with 16 giant aneurysms (12%). Eighty aneurysms (62%) were treated microsurgically, and 37 (28%) were treated conservatively due to poor medical and neurological status of the patient or due to technical reasons during the early years of the patient series. No connective tissue disorders common to pediatric aneurysm patients were diagnosed in this series, with the exception of 1 patient with tuberous sclerosis complex. The mean follow-up duration was 24.8 years (range 0-55.8 years). At the end of follow-up, 71 patients (62%) had a good outcome, 3 (3%) were dependent, and 40 (35%) had died. Twenty-seven deaths (68%) were assessed to be aneurysm-related. Factors correlating with a favorable long-term outcome were good neurological condition of the patient on admission, aneurysm location in the anterior circulation, complete aneurysm closure, and absence of vasospasm. Six patients developed symptomatic de novo aneurysms after a median of 25 years (range 11-37 years). Fourteen patients (12%) had a family history of aneurysms. There was no increased incidence for cardiovascular diseases in long-term follow-up. CONCLUSIONS Most aneurysms were ruptured and of medium size. Internal carotid artery bifurcation was the most frequent location of the aneurysms. There was a male predominance of pediatric patients with aneurysms. Most patients experienced good recovery, with 91% of the long-term survivors living at home independently without assistance and meaningfully employed. Altogether, almost a third of these patients finished high school and one-fifth had a college or university degree. Pediatric patients had a tendency to develop de novo aneurysms.

High risk population isolate reveals low frequency variants predisposing to intracranial aneurysms

3% of the population develops saccular intracranial aneurysms (sIAs), a complex trait, with a sporadic and a familial form. Subarachnoid hemorrhage from sIA (sIA-SAH) is a devastating form of stroke. Certain rare genetic variants are enriched in the Finns, a population isolate with a small founder population and bottleneck events. As the sIA-SAH incidence in Finland is >2× increased, such variants may associate with sIA in the Finnish population. We tested 9.4 million variants for association in 760 Finnish sIA patients (enriched for familial sIA), and in 2,513 matched controls with case-control status and with the number of sIAs. The most promising loci (p<5E-6) were replicated in 858 Finnish sIA patients and 4,048 controls. The frequencies and effect sizes of the replicated variants were compared to a continental European population using 717 Dutch cases and 3,004 controls. We discovered four new high-risk loci with low frequency lead variants. Three were associated with the case-control status: 2q23.3 (MAF 2.1%, OR 1.89, p 1.42×10-9); 5q31.3 (MAF 2.7%, OR 1.66, p 3.17×10-8); 6q24.2 (MAF 2.6%, OR 1.87, p 1.87×10-11) and one with the number of sIAs: 7p22.1 (MAF 3.3%, RR 1.59, p 6.08×-9). Two of the associations (5q31.3, 6q24.2) replicated in the Dutch sample. The 7p22.1 locus was strongly differentiated; the lead variant was more frequent in Finland (4.6%) than in the Netherlands (0.3%). Additionally, we replicated a previously inconclusive locus on 2q33.1 in all samples tested (OR 1.27, p 1.87×10-12). The five loci explain 2.1% of the sIA heritability in Finland, and may relate to, but not explain, the increased incidence of sIA-SAH in Finland. This study illustrates the utility of population isolates, familial enrichment, dense genotype imputation and alternate phenotyping in search for variants associated with complex diseases.

Basal brain injury in aneurysm surgery.

OBJECTIVE The goal of this study was to determine the frequency of lesions in the basal frontotemporal area that were related to surgical damage to the brain tissue. METHODS A prospective series of 101 patients with ruptured intracranial aneurysms were examined with high-field magnetic resonance imaging, 2 to 6 years (mean, 3.3 yr) after early surgery. RESULTS Lesions in the basal frontotemporal region, on the side of the pterional approach, were observed for 36 patients. These lesions were not visible in computed tomographic scans obtained pre- or postoperatively or 3 months after subarachnoid hemorrhage. Patients with ruptured aneurysms in the anterior communicating artery exhibited fewer of these lesions than did patients with aneurysms in the internal carotid artery or middle cerebral artery; this difference was not statistically significant. The age of the patient, the duration and depth of hypotension, the amount of blood or ventricular enlargement in pre- and postoperative computed tomographic scans, and the incidence and severity of angiographic vasospasm in pre- and postoperative angiograms did not predict the existence of these lesions. The clinical conditions of the patients, as assessed using the Glasgow Outcome Scale, at 3 months after surgery and at the time of magnetic resonance imaging did not predict the existence of these lesions. Nine of the 10 patients who underwent surgical treatment of unruptured aneurysms on the contralateral side exhibited no signs of tissue damage. CONCLUSION Surgical treatment of ruptured intracranial aneurysms seems to cause damage in the basal frontotemporal region in one-third of patients. The significance of these lesions remains unclear.

Long-term outcome of patients with multiple cerebral cavernous malformations.

OBJECTIVEMultiple cerebral cavernous malformations (MCCMs) typically occur in patients with a family history of these lesions. Literature on MCCMs is scarce, and little is known about their natural history. METHODSOf 264 consecutive patients with cerebral cavernomas treated at the Department of Neurosurgery, Helsinki University Central Hospital, in the past 27 years, 33 patients had MCCMs. Lesions were categorized according to the Zabramski classification scale. Follow-up questionnaires were sent to all patients. Outcome was assessed using the Glasgow Outcome Scale, and amelioration of epilepsy was assessed using the Engel scale. All clinical data were analyzed retrospectively. RESULTSThe mean age of patients at diagnosis was 44 years. Sex presentation was almost equal. Nine percent of all patients had a family history of the disease. Patients presented with epilepsy, acute headache, and focal neurological deficits. MCCMs were incidental findings in 2 patients. Altogether, 416 cavernomas were found: 70% supratentorial and 30% infratentorial. Fifteen patients had symptomatic hemorrhage before admission to our department. Surgery was performed on 18 patients. In most cases, the largest cavernoma was removed. Postoperatively, 1 patient experienced temporary hemiparesis, and another developed permanent motor dysphasia. No mortalities occurred. The mean follow-up time was 7.7 years. Twenty-six patients (79%) were in good condition. Among patients with epilepsy who underwent lesionectomy, 70% had an Engel class I outcome. On follow-up magnetic resonance imaging, 52 de novo cavernomas were found. CONCLUSIONSurgical treatment of patients with MCCMs is safe. An extirpation of the clinically active cavernoma prevents further bleedings and improves outcome of epilepsy.

Transition From Microscopic to Endoscopic Transsphenoidal Surgery for Nonfunctional Pituitary Adenomas

OBJECTIVE At our institution, a total of 320 patients were operated on between 2000 and 2010 for a newly diagnosed pituitary adenoma. In an attempt to improve quality of tumor resection, the transsphenoidal microscopic technique was replaced by the endoscopic technique in June 2008. This retrospective single center study compares the outcomes after microscopic (n = 144) and endoscopic (n = 41) tumor surgery of all patients operated on for a nonfunctional pituitary adenoma. METHODS Tumor size and location, Knosp grade, prevalence of anterior hypopituitarism, diabetes insipidus, visual acuity/fields, complication rates, and operation time were compared between the groups. RESULTS At the 3-month follow-up, hypopituitarism had improved in 7% of patients in the microscopic group and in 9% in the endoscopic group, and had further impaired in 13% and 9%, respectively. At the 3-month follow-up magnetic resonance imaging, a total tumor removal was achieved in 45% versus 56% of patients, respectively (P = not significant [NS]). Visual fields had normalized or improved in 90% versus 88% of patients, respectively (P = NS). Postoperative cerebrospinal fluid leak occurred in 3.5% versus 2.4% (P = NS), and diabetes insipidus (transient or permanent) in 7.6% versus 4.9% (P = NS) of cases, respectively. Larger tumor size (P < 0.0005) and endoscopic technique (P = 0.03) were independent predictors of increased mean operative time. CONCLUSIONS Initial results with the endoscopic technique were statistically similar to those achieved with the microscopic technique. However, there was a trend toward improved outcomes and fewer complications in the endoscopic group.

De Novo and Recurrent Aneurysms in Pediatric Patients With Cerebral Aneurysms

Background and Purpose— Long-term angiographic follow-up studies on pediatric aneurysm patients are scarce. Methods— We gathered long-term clinical and angiographic follow-up data on all pediatric aneurysm patients (⩽18 years at diagnosis) treated at the Department of Neurosurgery, Helsinki University Central Hospital, between 1937 and 2009. Results— Fifty-nine patients with cerebral aneurysms in childhood had long-term clinical and radiological follow-up (median, 34 years; range, 4–56 years). Twenty-four patients (41%) were diagnosed with altogether 25 de novo and 11 recurrent aneurysms, with 9 (25%) of the aneurysms being symptomatic. New subarachnoid hemorrhage occurred in 7 patients; 4 of these patients died. Eight patients (33%) had multiple new aneurysms. The annual rate of hemorrhage was 0.4%, and the annual rate for the development of de novo or recurrent aneurysm was 1.9%. There were no de novo aneurysms in 7 patients with previously unruptured aneurysms. However, 1 recurrent aneurysm was diagnosed. Current and previous smoking (risk ratio, 2.44; 95% confidence interval, 1.07–5.55) was the only statistically significant risk factor for de novo and recurrent aneurysm formation in patients with previous subarachnoid hemorrhage, whereas hypertension, sex, or age at onset had no statistically significant effect. Smoking was also a statistically significant risk factor for new subarachnoid hemorrhage. Conclusions— Patients with ruptured intracranial aneurysms in childhood have a high risk for new aneurysms and new subarachnoid hemorrhage, especially if they start to smoke as adults. Life-long angiographic follow-up is mandatory.

A new, more accurate classification of middle cerebral artery aneurysms: computed tomography angiographic study of 1,009 consecutive cases with 1,309 middle cerebral artery aneurysms.

BACKGROUND Classification of middle cerebral artery (MCA) aneurysms is sometimes difficult because the identification of the main MCA bifurcation, the key for accurate classification of MCA aneurysms, is inconsistent and somewhat subjective. OBJECTIVE To use the meeting point of the M1 and M2 trunks as an objective, generally accepted, and angiographically evident hallmark for identification of MCA bifurcation and more accurate classification of MCA aneurysms. METHODS We reviewed the computed tomographic angiography data of 1009 consecutive patients with 1309 MCA aneurysms. The M2 trunks were followed proximally until their meeting with the M1 trunk at the main MCA bifurcation. The aneurysms were classified according to their relative location: proximal, at, or distal to the MCA bifurcation. The M1 aneurysms were further subgrouped into M1 early cortical branch aneurysms and M1 lenticulostriate artery aneurysms, extending the classic 3-group classification of MCA aneurysms into a 4-group classification. RESULTS The main MCA bifurcation was the most common location for MCA aneurysms, harboring 829 aneurysms (63%). The 406 M1 aneurysms comprised 242 M1 early cortical branch aneurysms (60%) and 164 M1 lenticulostriate artery aneurysms (40%). We found 106 MCA aneurysms (8%) at the origin of large early frontal branches simulating M2 trunks liable to be misclassified as MCA bifurcation aneurysms. Even though 51% of the 407 ruptured MCA aneurysms were associated with an intracerebral hematoma, this did not affect the classification. CONCLUSION Studying MCA angioarchitecture and applying the 4-group classification of MCA aneurysms is practical and facilitates the accurate classification of MCA aneurysms, helping to improve surgical outcome.

Hyperoxemia and long-term outcome after traumatic brain injury

IntroductionThe relationship between hyperoxemia and outcome in patients with traumatic brain injury (TBI) is controversial. We sought to investigate the independent relationship between hyperoxemia and long-term mortality in patients with moderate-to-severe traumatic brain injury.MethodsThe Finnish Intensive Care Consortium database was screened for mechanically ventilated patients with a moderate-to-severe TBI. Patients were categorized, according to the highest measured alveolar-arterial O2 gradient or the lowest measured PaO2 value during the first 24 hours of ICU admission, to hypoxemia (<10.0 kPa), normoxemia (10.0 to 13.3 kPa) and hyperoxemia (>13.3 kPa). We adjusted for markers of illness severity to evaluate the independent relationship between hyperoxemia and 6-month mortality.ResultsA total of 1,116 patients were included in the study, of which 16% (n = 174) were hypoxemic, 51% (n = 567) normoxemic and 33% (n = 375) hyperoxemic. The total 6-month mortality was 39% (n = 435). A significant association between hyperoxemia and a decreased risk of mortality was found in univariate analysis (P = 0.012). However, after adjusting for markers of illness severity in a multivariate logistic regression model hyperoxemia showed no independent relationship with 6-month mortality (hyperoxemia vs. normoxemia OR 0.88, 95% CI 0. 63 to 1.22, P = 0.43; hyperoxemia vs. hypoxemia OR 0.97, 95% CI 0.63 to 1.50, P = 0.90).ConclusionHyperoxemia in the first 24 hours of ICU admission after a moderate-to-severe TBI is not predictive of 6-month mortality.