Norberto Andaluz

Recent trends in the treatment of cerebral aneurysms: analysis of a nationwide inpatient database

OBJECT The most appropriate treatment for cerebral aneurysms, both ruptured and unruptured, is currently under debate, and updated guidelines have yet to be defined. The authors attempted to identify trends in therapy for cerebral aneurysms in the US as well as outcomes. METHODS The authors retrospectively reviewed data from the Nationwide Inpatient Sample hospital discharge database (Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality) for the period 1993-2003. Multiple variables were categorized and subjected to statistical analysis for International Classification of Diseases, 9th Revision, Clinical Modification codes related to subarachnoid hemorrhage (SAH), unruptured aneurysm, and clipping and endovascular treatment of cerebral aneurysm. RESULTS During the study period, the numbers of discharges remained stable for SAH but doubled for unruptured aneurysms. Concomitantly, the number of aneurysms treated with clip placement remained stable, and the number treated by means of endovascular procedures doubled. By the studys end, the mortality rates had decreased 20% for SAH and 50% for unruptured aneurysms. Increasing age was associated with increased mortality rates, mean length of hospital stay (LOS), and mean charges (p < 0.01). Endovascular treatment was used more often in older patients (p < 0.01). Teaching status and larger hospital size were associated with higher charges and longer hospital stays (although the association was not statistically significant) and with better outcomes (p < 0.05) and lower mortality rates (p < 0.05), especially in patients who underwent aneurysm clipping (p < 0.01). Endovascular treatment was associated with significantly higher mortality rates in small hospitals (p < 0.001) and steadily increasing morbidity rates (45%). Morbidity rates, mean LOS, and mean charges were higher for aneurysm clipping (p < 0.01). CONCLUSIONS From 1993 to 2003, endovascular techniques for aneurysm occlusion have been increasingly used, while the use of surgical clipping procedures has remained stable. Toward the end of the study period, better overall outcomes were observed in the treatment of cerebral aneurysms, both ruptured and unruptured. Large academic centers were associated with better results, particularly for surgical clip placement.

Experimental animal models of intracerebral hemorrhage.

Experimental animal ICH models are able to reproduce the overall important pathophysiologic events documented in human ICH, including edema development, markedly reduced metabolism, and tissue pathologic responses. Thus, ICH models serve as an important tool for new understanding of the mechanisms underlying brain injury after an intracerebral bleed. Currently, ongoing studies in several laboratories using these models investigating secondary inflammatory responses as well as intracellular signaling and molecular events are expected to provide therapeutic targets for treating ICH. Future studies should also be directed at one aspect of ICH modeling that has received little attention--potential differences in the hemostatic systems and physical and biochemical properties of clots in animals that might make their susceptibility to aspiration and/or fibrinolytic drugs and rates of rehemorrhage different than in human beings. Also, future efforts should be directed toward the development of a model that mimics the pathophysiologic processes that lead to spontaneous ICH, progression of hemorrhage, and the recurrence of bleeding in human beings. This model would not only provide better understanding of the dynamic events leading to ICH and tissue injury but should also lead to the development of highly effective pharmacologic and surgical treatments.

Yield of further diagnostic work-up of cryptogenic subarachnoid hemorrhage based on bleeding patterns on computed tomographic scans.

BACKGROUND Subarachnoid hemorrhage (SAH) is cryptogenic in 15% of cases. Despite reports of proven recurrence, additional diagnostic studies are not often recommended when no abnormalities were identified on the initial study with digital subtraction angiography (DSA). In our retrospective review of outcomes after cryptogenic SAH, we identify diagnostic strategies that most often yielded the source of bleeding. METHODS Of 719 patients admitted with SAH from 1998 to 2003, 92 (12.8%) patients had findings negative for a bleeding source on initial four-vessel DSA. Based on computed tomographic scans, SAH was categorized as perimesencephalic in 45 patients (mean age, 48 yr) and nonperimesencephalic in 47 patients (mean age, 53 yr). All underwent cerebral magnetic resonance imaging and magnetic resonance angiography; select patients underwent additional studies. Multiple variables were analyzed. Outcomes at the time of discharge were categorized according to the modified Rankin Scale. RESULTS After perimesencephalic SAH, 44 (97.8%) patients had good scores (0-2) on the modified Rankin Scale, and one patient (2.2%) was deceased. Six (13.3%) patients experienced complications, one (2.2%) experienced vasospasm, and two (4.4%) had hydrocephalus. Further studies in perimesencephalic SAH yielded a diagnosis in 13.9% of patients. After nonperimesencephalic SAH (mean Hunt and Hess score of 2.2), hospital and intensive care unit stays averaged 12 and 8.3 days, respectively. Outcomes were good in 30 (63.8%) patients, poor (modified Rankin Scale 3-5) in 11 (23.4%), and six (12.8%) died. Further studies in nonperimesencephalic SAH exhibited positive findings in 21.3% of patients. Eighteen (38.3%) patients had complications, nine (19.1%) experienced vasospasm, four (8.5%) had recurrent SAH, and 12 (25.5%) had hydrocephalus. CONCLUSION Compared with perimesencephalic SAH, nonperimesencephalic SAH was associated with significantly (P < 0.01) longer hospital and intensive care unit stays, greater complication rates, and worse outcomes. Positive findings after further work-up after initial negative DSA in 16% of our patient population confirms that cryptogenic SAH is not necessarily nonaneurysmal, but that a bleeding risk exists. Therefore, we advocate repeat DSA and/or computed tomographic angiography after cryptogenic SAH.

Fenestration of the lamina terminalis as a valuable adjunct in aneurysm surgery.

OBJECTIVE: Hydrocephalus, vasospasm, and frontobasal injury are common complications after aneurysmal subarachnoid hemorrhage (SAH) from anterior communicating artery aneurysms. Previous studies have suggested that fenestration of the lamina terminalis (FLT) during surgery may be associated with reduced rates of shunt-dependent hydrocephalus and vasospasm. We report 106 patients affected by anterior communicating artery aneurysms and Fisher Grade 3 aneurysmal SAH and the affect of FLT on shunt-dependent hydrocephalus, vasospasm, and frontobasal injury. METHODS: During a 3-year period, 53 patients underwent FLT and 53 did not. We prospectively evaluated admission and discharge clinical grades, hydrocephalus at admission, occurrence of clinical vasospasm, need for interventional vasospasm therapy, frontobasal hypodensity incidence, and permanent ventriculoperitoneal shunting requirement. Follow-up ranged from 3 to 35 months (mean, 17.9 mo). RESULTS: Shunting incidence after aneurysmal SAH with hydrocephalus was 4.25% in patients who underwent FLT and 13.9% in patients who did not (P < 0.001). Clinical cerebral vasospasm occurred in 29.6% of patients who underwent FLT and in 54.7% of patients who did not (P < 0.001). Frontobasal hypodensity was identified postoperatively in 0% of patients who underwent FLT and in 5% of patients who did not. Good outcome was reported in 69.81% of patients who underwent FLT and in 33.96% of patients who did not (P < 0.001). Poor outcome was associated with higher Hunt and Hess grades, need for ventricular drainage, elevated intracranial pressure, and multiple interventional vasospasm therapies. No complications were linked to FLT. CONCLUSION: FLT was associated with statistically significant decreases in shunting rates, incidence of vasospasm, and better outcomes. We recommend its routine use in patients with Fisher Grade 3 anterior communicating artery aneurysmal SAH.

Recent trends in the treatment of spontaneous intracerebral hemorrhage: analysis of a nationwide inpatient database.

OBJECT Recently updated guidelines failed to reflect significant progress in the treatment of intracerebral hemorrhage (ICH). Using data from a nationwide hospital database, the authors identified recent trends in therapy and outcomes for ICH, as well as the effect of associated comorbidities and procedures, including surgery. METHODS Data from the Nationwide Inpatient Sample hospital discharge database (Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality) for the period 1993-2005 was retrospectively reviewed. Multiple variables were categorized and subjected to statistical analysis for codes related to ICH from the International Classification of Diseases, 9th revision, Clinical Modification. Data linked by the Nationwide Inpatient Sample database to associated diagnoses and procedures were also retrieved and analyzed. RESULTS The number of discharges remained constant for ICH. The mortality rate remained unchanged at an average of 31.6%, whereas routine discharges (home) steadily declined by 25%, and discharges other than home doubled (p < 0.01). By the end of the study, length of hospital stay decreased by 30% (p < 0.01), and mean hospital charges steadily increased to more than twice the original figures. Arterial hypertension was the most frequently associated comorbidity. Seizures were associated with longer hospital stays and higher mean hospital charges. Craniotomy was associated with decreased mortality rates but also with worse outcomes and lower rates of patients discharged home (p < 0.01). No geographic differences in treatment and outcomes were noted. CONCLUSIONS From 1993 to 2005, no significant progress in treatment and prevention of ICH was noted. There were no regional differences in the treatment and outcome of ICH. The role of surgery for ICH remains uncertain, and large-scale controlled studies are greatly needed to clarify this role.

Anatomic and clinical study of the orbitopterional approach to anterior communicating artery aneurysms

OBJECTIVE To evaluate the orbitopterional approach to anterior communicating artery (AComA) aneurysms, on the basis of the quantification of this surgical exposure, compared with the pterional approach, in a cadaveric study and a retrospective review of data for 40 patients who underwent clipping of AComA aneurysms via the orbitopterional approach. METHODS In an anatomic study, four cadaveric heads underwent pterional craniotomies on the left side and orbitopterional craniotomies on the right side. A fifth head was initially subjected to bilateral pterional craniotomies and then underwent bilateral orbital osteotomies, for direct comparison of these approaches. Using frameless stereotaxy, we quantified the angles of exposure and surgical field depths provided by the pterional and orbitopterional craniotomies. In a clinical study, 40 patients who underwent clipping of AComA aneurysms via orbitopterional approaches were evaluated for basal brain injury, the need for resection of the gyrus rectus, dissection of the sylvian fissure, and approach-related complications. The incidence of postoperative hydrocephalus among patients with subarachnoid hemorrhage who underwent lamina terminalis fenestration was also reviewed. RESULTS The angles of observation were increased 46% in the axial plane (orbitopterional, 72.92 +/- 6.57 degrees; pterional, 49.75 +/- 2.27 degrees; P < 0.01) and 137.5% in the projection plane (orbitopterional, 8 +/- 2.19 degrees; pterional, 19 +/- 1.78 degrees; P < 0.01). The surgical window depth was decreased 13% with the orbitopterional approach (P < 0.05). Clinically, there was no incidence of frontobasal hypodensities on postoperative computed tomographic scans. Three patients (7.5%) required resection of the gyrus rectus. No patient required sylvian fissure dissection for aneurysm exposure. Two of 29 patients (6.9%) who survived subarachnoid hemorrhage required ventriculoperitoneal shunts despite lamina terminalis fenestration. No approach-related complications were recognized. CONCLUSION The orbitopterional approach improved the observation of the AComA complex and seemed to decrease the risk of intraoperative brain damage.

Inverse neurovascular coupling to cortical spreading depolarizations in severe brain trauma

Cortical spreading depolarization causes a breakdown of electrochemical gradients following acute brain injury, and also elicits dynamic changes in regional cerebral blood flow that range from physiological neurovascular coupling (hyperaemia) to pathological inverse coupling (hypoperfusion). In this study, we determined whether pathological inverse neurovascular coupling occurred as a mechanism of secondary brain injury in 24 patients who underwent craniotomy for severe traumatic brain injury. After surgery, spreading depolarizations were monitored with subdural electrode strips and regional cerebral blood flow was measured with a parenchymal thermal diffusion probe. The status of cerebrovascular autoregulation was monitored as a correlation between blood pressure and regional cerebral blood flow. A total of 876 spreading depolarizations were recorded in 17 of 24 patients, but blood flow measurements were obtained for only 196 events because of technical limitations. Transient haemodynamic responses were observed in time-locked association with 82 of 196 (42%) spreading depolarizations in five patients. Spreading depolarizations induced only hyperaemic responses (794% increase) in one patient with intact cerebrovascular autoregulation; and only inverse responses (-24% decrease) in another patient with impaired autoregulation. In contrast, three patients exhibited dynamic changes in neurovascular coupling to depolarizations throughout the course of recordings. Severity of the pathological inverse response progressively increased (-14%, -29%, -79% decrease, P < 0.05) during progressive worsening of cerebrovascular autoregulation in one patient (Pearson coefficient 0.04, 0.14, 0.28, P < 0.05). A second patient showed transformation from physiological hyperaemic coupling (44% increase) to pathological inverse coupling (-30% decrease) (P < 0.05) coinciding with loss of autoregulation (Pearson coefficient 0.19 → 0.32, P < 0.05). The third patient exhibited a similar transformation in brain tissue oxygenation, a surrogate of blood flow, from physiologic hyperoxic responses (20% increase) to pathological hypoxic responses (-14% decrease, P < 0.05). Pathological inverse coupling was only observed with electrodes placed in or adjacent to evolving lesions. Overall, 31% of the pathological inverse responses occurred during ischaemia (<18 ml/100 g/min) thus exacerbating perfusion deficits. Average perfusion was significantly higher in patients with good 6-month outcomes (46.8 ± 6.5 ml/100 g/min) than those with poor outcomes (32.2 ± 3.7 ml/100 g/min, P < 0.05). These results establish inverse neurovascular coupling to spreading depolarization as a novel mechanism of secondary brain injury and suggest that cortical spreading depolarization, the neurovascular response, cerebrovascular autoregulation, and ischaemia are critical processes to monitor and target therapeutically in the management of acute brain injury.

Indications for endovascular therapy for refractory vasospasm after aneurysmal subarachnoid hemorrhage: Experience at the University of Cincinnati

BACKGROUND Transluminal balloon angioplasty (TBA) and intra-arterial papaverine (IAP) appear to be valuable alternatives for the treatment of aneurysmal subarachnoid hemorrhage (SAH)-induced vasospasm refractory to maximal medical therapy. Although widely used, guiding principles for the implementation of TBA and IAP are not yet established. Based on our retrospective analysis, we define guidelines for endovascular therapy for refractory vasospasm based on our clinical results, adverse effects, and pattern of vasospasm. METHODS Medical records of 62 patients who experienced aneurysmal SAH-induced vasospasm refractory to hypervolemic, hypertensive, hyperdynamic therapy, and who were treated with IAP or TBA were reviewed. Fifty patients met the inclusion criteria for analysis. After careful scrutiny, two types of responses to endovascular treatment were identified. On the basis of that grouping, patients were divided into two groups according to the number of arterial segments involved, that is, monoterritorial and multiterritorial vasospasm. Multiple variables were analyzed. RESULTS Patients undergoing multiple endovascular procedures exhibited the worst outcomes. Patients in the monoterritorial group experienced a higher incidence of clinical improvement and better outcomes after endovascular treatment. Elevated intracranial pressure (ICP) and ICP-related deaths were more prominent in the multiterritorial group of patients. Sustained ICP elevation after administration of IAP was strongly associated with poor outcome in the multiterritorial group. CONCLUSIONS IAP is indicated as an early potential single-dose infusion in distal monoterritorial vasospasm, if angioplasty is impossible or unsafe. The use of IAP in bilateral diffuse vasospasm is discouraged because of the high susceptibility of these patients to develop elevated ICP. Multiple IAP infusions seem to have no significant impact on patient outcome. Balloon angioplasty seems to be indicated at an early juncture in patients with multiterritorial proximal vasospasm.

The Insertion and Management of External Ventricular Drains: An Evidence-Based Consensus Statement : A Statement for Healthcare Professionals from the Neurocritical Care Society.

Abstract External ventricular drains (EVDs) are commonly placed to monitor intracranial pressure and manage acute hydrocephalus in patients with a variety of intracranial pathologies. The indications for EVD insertion and their efficacy in the management of these various conditions have been previously addressed in guidelines published by the Brain Trauma Foundation, American Heart Association and combined committees of the American Association of Neurological Surgeons and the Congress of Neurological Surgeons. While it is well recognized that placement of an EVD may be a lifesaving intervention, the benefits can be offset by procedural and catheter-related complications, such as hemorrhage along the catheter tract, catheter malposition, and CSF infection. Despite their widespread use, there are a lack of high-quality data regarding the best methods for placement and management of EVDs to minimize these risks. Existing recommendations are frequently based on observational data from a single center and may be biased to the authors’ view. To address the need for a comprehensive set of evidence-based guidelines for EVD management, the Neurocritical Care Society organized a committee of experts in the fields of neurosurgery, neurology, neuroinfectious disease, critical care, pharmacotherapy, and nursing. The Committee generated clinical questions relevant to EVD placement and management. They developed recommendations based on a thorough literature review using the Grading of Recommendations Assessment, Development, and Evaluation system, with emphasis placed not only on the quality of the evidence, but also on the balance of benefits versus risks, patient values and preferences, and resource considerations.

Spreading depression in continuous electroencephalography of brain trauma

Cortical spreading depolarizations are a pathophysiological mechanism and candidate target for advanced monitoring in acute brain injury. Here we investigated manifestations of spreading depolarization in continuous electroencephalography (EEG) as a broadly applicable, noninvasive method for neuromonitoring.