Anatomy of the Great Posterior Radiculomedullary Artery.

BACKGROUND AND PURPOSE: Although considerable variability exists as to the overall caliber of radiculomedullary arteries, dominant radiculomedullary arteries such as the artery of Adamkiewicz exist. The existence of a great posterior radiculomedullary artery has attracted little attention and has been a matter of debate. The aim of this anatomic study was to determine the presence or absence of the great posterior radiculomedullary artery. MATERIALS AND METHODS: We performed microsurgical dissection on formaldehyde-fixed cadaveric human spinal cords. The artery of Adamkiewicz in the spinal cord specimens (n = 50) was injected with colored latex until the small-caliber arterial vessels were filled and the great posterior radiculomedullary artery was identified. The course, diameter, and location of great posterior radiculomedullary artery were documented. RESULTS: A great posterior radiculomedullary artery was identified in 36 (72%) spinal cord specimens. In 11 (22%) specimens, bilateral great posterior radiculomedullary arteries were present. In 13 cases (26%), a unilateral left-sided great posterior radiculomedullary artery was identified. In 11 cases (22%), a unilateral right-sided great posterior radiculomedullary artery was identified. In 1 specimen (2%), 3 right-sided great posterior radiculomedullary arteries were noted. The average size of the great posterior radiculomedullary arteries was 0.44 mm (range, 0.120-0.678 mm on the left and 0.260-0.635 mm on the right). CONCLUSIONS: A great posterior radiculomedullary artery is present in most (72%) individuals. The authors describe the microsurgical anatomy of the great posterior radiculomedullary artery with emphasis on its morphometric parameters as well as its implications for spinal cord blood supply. Variations of the arterial supply to the dorsal cord are of great importance due to their implications for ischemic events, endovascular procedures, and surgical approaches.

Local Hemodynamic Conditions Associated with Focal Changes in the Intracranial Aneurysm Wall.

BACKGROUND AND PURPOSE: Aneurysm hemodynamics has been associated with wall histology and inflammation. We investigated associations between local hemodynamics and focal wall changes visible intraoperatively. MATERIALS AND METHODS: Computational fluid dynamics models were constructed from 3D images of 65 aneurysms treated surgically. Aneurysm regions with different visual appearances were identified in intraoperative videos: 1) "atherosclerotic" (yellow), 2) "hyperplastic" (white), 3) "thin" (red), 4) rupture site, and 5) "normal" (similar to parent artery), They were marked on 3D reconstructions. Regional hemodynamics was characterized by the following: wall shear stress, oscillatory shear index, relative residence time, wall shear stress gradient and divergence, gradient oscillatory number, and dynamic pressure; these were compared using the Mann-Whitney test. RESULTS: Hyperplastic regions had lower average wall shear stress (P = .005) and pressure (P = .009) than normal regions. Flow conditions in atherosclerotic and hyperplastic regions were similar but had higher average relative residence time (P = .03) and oscillatory shear index (P = .04) than thin regions. Hyperplastic regions also had a higher average gradient oscillatory number (P = .002) than thin regions. Thin regions had lower average relative residence time (P < .001), oscillatory shear index (P = .006), and gradient oscillatory number (P < .001) than normal regions, and higher average wall shear stress (P = .006) and pressure (P = .009) than hyperplastic regions. Thin regions tended to be aligned with the flow stream, while atherosclerotic and hyperplastic regions tended to be aligned with recirculation zones. CONCLUSIONS: Local hemodynamics is associated with visible focal wall changes. Slow swirling flow with low and oscillatory wall shear stress was associated with atherosclerotic and hyperplastic changes. High flow conditions prevalent in regions near the flow impingement site characterized by higher and less oscillatory wall shear stress were associated with local "thinning" of the wall.

Flow Conditions in the Intracranial Aneurysm Lumen Are Associated with Inflammation and Degenerative Changes of the Aneurysm Wall.

BACKGROUND AND PURPOSE: Saccular intracranial aneurysm is a common disease that may cause devastating intracranial hemorrhage. Hemodynamics, wall remodeling, and wall inflammation have been associated with saccular intracranial aneurysm rupture. We investigated how saccular intracranial aneurysm hemodynamics is associated with wall remodeling and inflammation of the saccular intracranial aneurysm wall. MATERIALS AND METHODS: Tissue samples resected during a saccular intracranial aneurysm operation (11 unruptured, 9 ruptured) were studied with histology and immunohistochemistry. Patient-specific computational models of hemodynamics were created from preoperative CT angiographies. RESULTS: More stable and less complex flows were associated with thick, hyperplastic saccular intracranial aneurysm walls, while slower flows with more diffuse inflow were associated with degenerated and decellularized saccular intracranial aneurysm walls. Wall degeneration (P = .041) and rupture were associated with increased inflammation (CD45+, P = .031). High wall shear stress (P = .018), higher vorticity (P = .046), higher viscous dissipation (P = .046), and high shear rate (P = .046) were associated with increased inflammation. Inflammation was also associated with lack of an intact endothelium (P = .034) and the presence of organized luminal thrombosis (P = .018), though overall organized thrombosis was associated with low minimum wall shear stress (P = .034) and not with the flow conditions associated with inflammation. CONCLUSIONS: Flow conditions in the saccular intracranial aneurysm are associated with wall remodeling. Inflammation, which is associated with degenerative wall remodeling and rupture, is related to high flow activity, including elevated wall shear stress. Endothelial injury may be a mechanism by which flow induces inflammation in the saccular intracranial aneurysm wall. Hemodynamic simulations might prove useful in identifying saccular intracranial aneurysms at risk of developing inflammation, a potential biomarker for rupture.

Ultrasound Screening of Men with Coronary Artery Disease for Abdominal Aortic Aneurysms: A Prospective Dual Center Study.

BACKGROUND AND AIMS: According to the heterogeneous results of previous studies, the prevalence of abdominal aortic aneurysm seems high among men with coronary artery disease. The associating risk factors for abdominal aortic aneurysm in this population require clarification. Our objective was to assess the prevalence of non-diagnosed abdominal aortic aneurysms in men with angiographically verified coronary artery disease and to document the associated co-morbidities and risk factors. MATERIAL AND METHODS: Altogether, 407 men with coronary artery disease were screened after invasive coronary angiography in two series at independent centers. Risk factor data were recorded and analyzed. RESULTS AND CONCLUSION: The mean age of the study cohort was 70.0 years (standard deviation: 11.0). The prevalence of previously undiagnosed abdominal aortic aneurysms in the whole screened population of 407 men was 6.1% (n = 25/407). In a multivariate analysis of the whole study population, the only significant risk factors for abdominal aortic aneurysm were age (odds ratio: 1.04, 95% confidence interval: 1.00-1.09) and history of smoking (odds ratio: 3.13, 95% confidence interval: 1.26-7.80). Non-smokers with abdominal aortic aneurysm were significantly older than smokers (mean age: 80.7 (standard deviation: 8.0) vs 68.0 (standard deviation: 11.1), p = 0.003), and age was a significant risk factor only among non-smokers (p = 0.011; p = 0.018 for interaction). Among smokers, the prevalence of abdominal aortic aneurysm was 8.8%, and 72% (n = 18/25) of all diagnosed abdominal aortic aneurysm patients were smokers. Prevalence of undiagnosed abdominal aortic aneurysms among patients with coronary artery disease is high, and history of smoking is the most significant risk factor for abdominal aortic aneurysm. Effectiveness of selective screening of abdominal aortic aneurysm in male patients with coronary artery disease warrants further studies.

Stroke volume-directed administration of hydroxyethyl starch or Ringer's acetate in sitting position during craniotomy.

BACKGROUND: To determine the volumes required for stable haemodynamics and possible effects on the coagulation, we studied stroke volume (SV)-directed administration of hydroxyethyl starch (HES 130 kDa/0.4) and Ringer's acetate (RAC) in neurosurgical patients operated on in a sitting position. METHODS: Thirty craniotomy patients were randomised to receive either HES or RAC. Before positioning, SV, measured by arterial pressure waveform analysis, was maximised by boluses of fluid until SV did not increase more than 10%. SV was maintained by repeated administration of fluid. RAC 3 ml/kg/h was infused in both groups during surgery. RESULTS: Comparable haemodynamics were achieved with the mean [standard deviation (SD)] cumulative doses of HES or RAC 271 (47) or 264 (50) ml (P = 0.699) before the sitting position. Mean (SD) doses of HES or RAC at 30 min after the positioning were 343 (94) or 450 (156) ml (P = 0.036), and at the end of surgery 464 (284) or 707 (425) ml, respectively (P = 0.087). The intraoperative fluid balance was more positive in the RAC than in the HES group [P = 0.044, 95% confidence interval (CI) -978 to -14]. Cardiac and stroke volume indexes [CI and stroke volume index (SVI)] increased in the HES group (P < 0.05) but not in the RAC group [non significant (N.S.)]. Neither coagulation profile nor blood loss differed between the groups. CONCLUSION: Fluid filling with HES boluses resulted in a positive response in CI and SVI during the sitting position. The 34% smaller volume of HES than crystalloid and less positive fluid balance in the HES group might be important in craniotomy patients with decreased brain compliance.

Health-related quality of life and cost-effectiveness of treatment in subarachnoid haemorrhage.

BACKGROUND: Treatment of aneurysmal subarachnoid haemorrhage (SAH) demands high healthcare resource utilization. Case fatality and disability remain as common outcomes of SAH. The purpose of this study was to perform a treatment cost-effectiveness analysis of patients with SAH. METHODS: We performed a long-term follow-up of the SAH patients treated in our institution over a 3-year period starting February 1998. Outcome 10 years after the SAH and treatment costs were evaluated. The health-related quality of life was evaluated using the EuroQol (EQ-5D) questionnaire and visual-analogue scale (VAS). The cost of a quality-adjusted life year (QALY) was calculated. RESULTS: Median follow-up time of the 178 patients was 10.8 years. Overall mortality rate was 24%. Of the 43 non-survivors, 42% died within 6 months. For the 135 survivors, the median EQ-5D index value was 1.00, which is similar to that for normal population. The median VAS value was 80, which is comparable to normal population's value. Of the survivors, 88% (119/135) were able to live at home and 63% (85/135) returned to work after SAH. The cost of neurosurgical treatment for one QALY was 1700€. CONCLUSION: Long-term outcome of survivors after aneurysmal SAH was relatively good: most of them lived at home, 63% had returned to work and 36% were still working. The quality of life index of the survivors was similar to that of normal populations, and the survivors were as satisfied with their health as people in general are. Cost of neurosurgical treatment and cost of a QALY gained were acceptable.

Post-traumatic frontal and parieto-occipital extradural haematomas: a retrospective analysis of 41 patients and review of the literature.

BACKGROUND: The purpose of this study was to analyse the differences between patients with frontal (FEDH) or parieto-occipital (POEDH) epidural haematomas and evaluate possible statistically significant prognostic factors. MATERIAL AND METHODS: In this retrospective study of a group of 41 patients with a FEDH (17) or POEDH (24 individuals), the authors analysed the influence of gender, age, type of injury, clinical presentation, Glasgow coma scale (GCS) score on admission, radiological findings, and time interval from trauma to surgery on outcomes. A good recovery and moderate disability were considered a "good" or "favourable outcome", whereas severe disability, a vegetative state or death was a "poor outcome". RESULTS: In the POEDH subgroup, a higher GCS score on admission and a younger age were statistically significant prognostic factors for a better outcome (p=0.006, rs=0.702). In the subgroup of patients with FEDHs, the results were not significant. However, patients with FEDHs more frequently had "good outcomes" than members of the POEDH subgroup (88.2 vs. 70.9%). Children (≤ 18 years old) constituted a smaller portion of the POEDH subgroup (12.5%) than those in the FEDH subgroup (41.2%). The evaluation of time intervals between the accident and surgery (≤ 24 h vs. > 24 h) showed no significant influence on outcomes in any of the studied subgroups. However, patients undergoing surgery within 24 h of their injury had a less favourable GCS score on admission than those operated on more than 24 h after their injury. Subacute and chronic clinical courses predominated in patients with a FEDH (10/17 FEDH vs. 11/22 POEDH). Different accompanying intradural lesions occurred in 12 patients of the POEDH subgroup, but only in 2 of the FEDH subgroup (50 vs. 11.8%). However, the presence of such lesions did not significantly deteriorate surgical outcomes in either of the subgroups.

Microsurgical technique for previously coiled aneurysms.

Since the introduction of Guglielmi detachable coils to treat intracranial aneurysms in 1991, the number of patients undergoing endovascular coiling has continuously risen as well as the number of those residual and recurrent previously coiled aneurysms that necessitate a microsurgical occlusion. Between July 1995 and August 2009 we retrospectively analyzed 81 patients with 82 previously coiled aneurysms treated microsurgically at two Finnish Neurosurgical University Hospitals, Helsinki and Kuopio. Fifty-eight aneurysms (71%) were located at anterior circulation and 24 (29%) at posterior circulation. Fifteen patients were operated on within the first month (early surgery) after coiling, whereas 66 were treated later (late surgery). Complete or partial removal of coils during surgery may facilitate clipping, but is significantly (P<0.001) more difficult to accomplish in late surgery. Removal of coils may also increase the chance for poor outcome. Chance of poor outcome increased also with intraoperative aneurysm rupture, size of the aneurysm and posterior circulation location. Good clinical outcome, three months after surgery, was achieved in 71 patients (88%); four patients were severely disabled, and six patients died (three of them due to poor clinical condition). Complete microsurgical occlusion of the residual previously coiled aneurysm is a high-risk procedure in large and giant aneurysms, and these patients should be referred to a dedicated neurovascular center to minimize surgical complications. Bypass procedures may be the best option for demanding growing lesions, especially those in posterior circulation.

Cost-effectiveness of decompressive craniectomy in traumatic brain injuries.

BACKGROUND AND PURPOSE: Decompressive craniectomy (DC) is used regularly in traumatic brain injury (TBI). There are, however, no cost-effectiveness studies of the procedure. METHODS: We evaluated the outcomes and treatment costs of all decompressive craniectomies performed between the 2000 and 2006 in a single institution to lower intractable intracranial pressure after TBI. The health-related quality of life was evaluated on the Euroqol (EQ-5D) questionnaire and on the visual-analogue scale (VAS), and cost of a quality-adjusted life year (QALY) was calculated. RESULTS: In this study of 54 patients, the median follow-up time was 5.6 years. Overall mortality rate was 41%. Of the 22 non-survivors, 73% died within 30 days. For 32 survivors, the median EQ-5D index value was 0.85, which is equal to the normal population. The median VAS value was 73, whilst normal population's value is 80. Of the survivors, 81% (26/32) were able to live at home and 31% (10/32) returned to work. The cost of neurosurgical treatment for one QALY was 2400 €. Estimation for all medical costs, including rehabilitation and anticipated future costs, resulted cost of a QALY 17,900 €. CONCLUSION: Mortality after severe TBI leading to DC was high, but amongst the survivors, the health-related quality of life was equal to normal population. Most survivors were able to live at home and were almost as satisfied with their health as in general people are. Cost of neurosurgical treatment was low, and also including all evaluated costs, cost of a QALY gained was acceptable.

Cost-effectiveness of decompressive craniectomy in non-traumatic neurological emergencies.

BACKGROUND: Decompressive craniectomy is used regularly in traumatic brain injury (TBI) and malignant middle cerebral artery infarction. Its benefits for other causes of non-traumatic brain swelling, if any, are unclear, especially after a devastating primary event. METHODS: We evaluated the outcomes as well as treatment costs of all emergency decompressive craniectomies performed between the 2000 and 2006 in a single institution to lower intractable intracranial pressure, excluding the standard indications TBI and malignant middle cerebral infarction. The health-related quality of life (HRQoL) was evaluated on the Euroqol (EQ-5D) scale, and cost of a quality-adjusted life year (QALY) calculated. RESULTS: The overall 3-year mortality rate was 62% for subarachnoid haemorrhage (SAH, 29 patients) and 31% for other neurological emergencies (13 patients). Patients with SAH were on average 13 years older than the other indications mean. Of the non-survivors, 45% died within a month and 95% within 1 year. Median EQ-5D index values were poor (0.15 for SAH and 0.62 for the other emergencies, versus 0.85 for the normal population), but of the survivors, 73% and 89% were able to live at home. The cost of neurosurgical treatment for one QALY was 11,000 € for SAH and 2000 € for other emergencies. CONCLUSION: Mortality after non-traumatic neurological emergencies leading to decompressive craniectomy was high, and the HRQoL index of the survivors was poor. Most survivors were, however, able to live at home, and the cost of neurosurgical treatment for a QALY gained was acceptable.

Posterior fossa extradural haematomas.

BACKGROUND: Posttraumatic epidural haematoma (EDH) of the temporal region is the most common site of supratentorial extradural bleeding; other locations are considered atypical. We reviewed 24 patients with EDH located in the posterior cranial fossa (PFEDH) treated at two neurosurgical centres between January 2000 and November 2006. MATERIAL AND METHODS: In the retrospective study we analysed gender and age distribution, type of injury, clinical presentation, Glasgow Coma Scale (GCS) score on admission, radiological images, interval between trauma and surgery, and outcome. RESULTS: 24 patients with PFEDH constituted 11.5% of 209 surgically treated individuals with EDH. The best outcomes were obtained by patients with GCS scores of 15-14 on admission. Patients in the fourth to seventh decade of life had less favourable outcomes than younger ones. More than half of the patients with PFEDH had associated intradural lesions. Only patients with concomitant brain contusion had a more favourable recovery. The 3 worst levels on the Glasgow Outcome Scale (GOS) were observed in patients suffering from subdural or intracerebral haematoma, or both, associated with the PFEDHs. The majority of patients with concurrent lesions and supratentorial extension of the haemorrhage were in the subgroup undergoing craniotomy between 24 and 72 h after injury. Patients treated in this time interval also had the most unfavourable outcomes. A classical lucid interval was observed only in one patient. The mortality rate in the series was 4.2%. CONCLUSION: The most significant factors influencing outcome in our patients were GCS on admission, age, and associated intradural lesions.

Management of dural arteriovenous fistulas - Helsinki and Kuopio experience.

Dural arteriovenous fistulas (DAVFs) are complex disorders, some of them with aggressive clinical behaviour. During past decades their treatment strategy has changed due to increased knowledge of their pathophysiology and natural history, and advances in treatment modalities. In asymptomatic cases or cases with mild symptoms in the absence of cortical venous drainage (CVD) no treatment is necessarily required, whereas aggressive DAVFs should be treated promptly by endovascular or microsurgical means.In our series of 323 patients with 333 fistulas, treated in two neurosurgical units in Finland since 1944, there were 265 true DAVFs and 68 Barrow type A caroticocavernous fistulas. Among the DAVFs there was a slight female predominance, 140 women (55%) and 115 men (45%), and the majority of the cases were located in the area of transverse and sigmoid sinuses. Mode of treatment in the early series was proximal ligation of feeding artery, and later craniotomy, endovascular treatment and radiosurgery, or combination of these treatments, with total occlusion rate being 53%.

Historical landmarks in vascular neurosurgery "On July 10th 2006, at the 70th Anniversary of the Department of Neurosurgery of Zürich Medical School".

Direct aneurysm surgery started more than 70 years ago. Introduction of cerebral angiography by Moniz in 20s and operating microscope by Yasargil in 60s were the real cornerstones in vascular neurosurgery. Since then the development of neuroanestesiology and further development of non-invasive imaging (MRA and CTA) together with the latest development of operating microscopes with intraoperative ICG angio have shifted vascular microneurosurgery to a different level to still compete with the 'non-invasiness' of endovascular therapy. There is an increasing demand to perform the already forgotten bypasses mastered only by few and with the high-flow techniques (e.g. ELANA) we can treat lesions that some time ago were considered impossible. Endovascular embolization to reduce the flow in AVM before surgery is very helpful in those cases that can not be treated by embolization or radiosurgery alone. We still need to find a way to detect aneurysms before they rupture and especially those thin-walled that are in an increased risk of rupture. Recent data on the pathobiology of the aneurysm wall may help us to better understanding of the growth mechanisms and it might be possible to develop more potent local or systemic pharmaceutical therapy to induce myo-intimal hyperplasia occluding the aneurysm and strengthening the wall to prevent rupture.

Heterogeneity of cerebral perfusion 1 week after haemorrhage is an independent predictor of clinical outcome in patients with aneurysmal subarachnoid haemorrhage.

BACKGROUND AND PURPOSE: Aneurysmal subarachnoid haemorrhage (aSAH) can be associated with acute global and regional decrease in cerebral perfusion. Furthermore, cerebral vasospasm may lead to development of delayed ischaemic deficits. The aim of the study was to find out whether cerebral perfusion heterogeneity, an indicator of cerebral microvascular function and autoregulation, measured by single-photon emission tomography (SPET), is able to predict the long-term clinical outcome of aSAH. METHODS: The perfusion SPET data of 55 patients with aSAH were analysed by dividing the brain into 384 regions of interest. Spatial perfusion heterogeneity was assessed by calculating the relative dispersions (RD, coefficient of variation) from the SPETs performed before treatment (RD1) and 1 week after early surgical or endovascular treatment of the ruptured aneurysm (RD2). Both RDs were compared to the clinical outcome (Glasgow Outcome Scale, GOS), neuropsychological test scores and late ischaemic findings in MRI 1 year after SAH. RESULTS: High RD2 (OR 1.96; 95% CI 1.18-3.26; p = 0.009) and poor clinical condition (Hunt and Hess grade) on admission (OR 6.60; 95% CI 1.78-24.52; p = 0.005) proved to be independent predictors of poor or moderate clinical outcome (GOS 1-4). RD2 was higher in patients with ischaemic findings in 12-month MRI than in those without ischaemic findings (p = 0.008). RD2 also correlated with neuropsychological outcome 1 year after aSAH. CONCLUSIONS: Perfusion heterogeneity is an independent predictor of the clinical outcome of aSAH and may thus be a valuable measure in the assessment of the disease.

Toll-like receptor 4 polymorphism is associated with coronary stenosis but not with the occurrence of acute or old myocardial infarctions.

OBJECTIVE: Atherosclerosis is considered to be a chronic inflammatory disease. Toll-like receptor 4 (TLR-4), a key mediator in activating inflammatory cascade, has an A-to-G functional polymorphism that changes aspartic acid to glycine at position 299. TLR-4 is activated by, for example, lipopolysaccharides. The purpose of this study was to investigate the role of a common Asp299Gly polymorphism of the TLR-4 gene in atherosclerosis. MATERIAL AND METHODS: The study comprised autopsy material from 657 men (the Helsinki Sudden Death Study; mean age 53, range 33-70 years). RESULTS: Fewer G-allele carriers had 3-vessel coronary artery disease compared with AA homozygotes (OR 0.32; 95 % CI, 0.12-0.88, p = 0.027), and they also had a lower mean value for maximal coronary stenosis (p = 0.019). TLR-4 polymorphism was not significantly associated with the occurrence of acute or old myocardial infarction (MI). CONCLUSIONS: The G allele of the TLR-4 gene, which is associated with a lower inflammation response, was associated with a lower risk of coronary stenosis but not with the occurrence of MI and hence is not a major factor in the development of coronary atherosclerosis.

Lateral supraorbital approach as an alternative to the classical pterional approach.

OBJECTIVE: The standard pterional approach has been used to approach aneurysms of the anterior circulation and the basilar tip, suprasellar tumors, cavernous lesions. The senior author (JH) established a lateral supraorbital approach as an alternative to the pterional approach after continuous trial and error. We describe the techniques of this approach based on clinical experiences. METHODS: The lateral supraorbital approach is more subfrontal and anterior than the pterional approach. This approach has been regularly used by the senior author (JH) in the last decade in more than 2000 operations for mostly aneurysms of anterior circulation, but also for tumors of the anterior fossa and parasellar area as well as the sphenoid wing area. RESULTS: This approach can be used to operate on most cases, in which the classical pterional approach would be used. There are almost no craniotomy-related complications with this approach. This approach is not suitable in certain lesions which need to be exposed from a more temporal perspective. CONCLUSION: This approach is simpler, faster, safer and less invasive than the classical pterional approach.