Michel Lonjon

Metagenomic Analysis of Brain Abscesses Identifies Specific Bacterial Associations

BACKGROUND The bacterial flora involved in brain abscess is often complex. In a previous study, using a metagenomic approach based on 16S ribosomal DNA (rDNA) amplification, we demonstrated that the diversity of the microbial flora involved in these infections was underestimated. METHODS We performed a 16S rDNA-based metagenomic analysis of cerebral abscesses from patients diagnosed from 2006 through 2010. All bacteria present in brain abscess specimens were identified, in view of the clinical and epidemiological characteristics of the patients. RESULTS Fifty-one patients were included in our study. By detecting polymicrobial infections in 19 patients, our strategy was significantly more discriminatory and enabled the identification of a greater number of bacterial taxa than did culture and conventional 16S rDNA polymerase chain reaction (PCR) and sequencing, respectively (P < 10(-2)). Data mining discriminated 2 distinct bacterial populations in brain abscess from dental and sinusal origin. In addition, of the 80 detected bacterial species, we identified 44 bacteria that had never been found in brain abscess specimens, including 22 uncultured bacteria. These uncultured agents mostly originated from the buccal or sinusal floras (P < 10(-2)) and were found in polymicrobial specimens (P < 10(-2)). CONCLUSIONS Cloning and sequencing of PCR-amplified 16S rDNA is a highly valuable method to identify bacterial agents of brain abscesses.

Occipitocervical Fixation Using Hooks and Screws for Upper Cervical Instability

OBJECTIVES Occipitocervical fixation is used for the treatment of nontraumatic upper cervical instabilities. To date, plates have been fixed with screws or wires. However, these devices are not indicated in the treatment of patients with severe osteoporosis or in instances of significant thinning of the occipital bone. We performed a clinical trial of a new type of fixation that uses cervical interlaminar hooks and occipital claws with hooks or with screws (CCD type; Sofamor-Danek, Roissy, France) for the treatment of nontraumatic upper cervical instabilities. METHODS Five women and one man ranging in age from 28 to 72 years (average age, 54 yr) were thus treated. The CCD type material had two rod plates and hooks allowing the proper placement of interlaminar and occipital claws. The occipital plate can also be directly screwed to the bone. Occipital hooks were used in four patients. The other two patients, who had occipitocervical congenital abnormalities that required an occipitocervical opening and an additional dural enlargement, underwent occipital screw fixation because of the previous opening of the foramen magnum. A cancellous iliac autograft allowed the usual fusion. RESULTS No postoperative complications were observed, and all patients experienced significant improvement of their neck pain. Four patients had neurological symptoms. The condition of two patients improved, and the condition of the other two stabilized. CONCLUSION This report confirms the interest of the CCD method to correct all types of upper cervical instabilities, even in cases of unusual thinning of the occipital bone or in osteoporotic states.

Endodermal cyst of the foramen magnum: case report and review of the literature.

Abstract The majority of endodermal cysts occur in the cervicothoracic spine, ventral to the cord. Intracranial locations are rare. We report a case involving the foramen magnum in a 14-year-old child, which was an incidental finding following a traumatic head injury. A review of the literature revealed six other cases involving this same location. These lesions are asymptomatic for a long time, and may cause brain stem medullary compression. Treatment is surgical. Effective simple removal can be achieved by a posterior approach.

Endovascular treatment of recurrent coiled aneurysms: assessment of complications and rebleeding during a decade in a single center.

Recurrence is the main drawback of aneurysmal coiling. Additional coiling must sometimes be considered in patients with reopened aneurysms and expose the patient to the risk of a new procedure. Our purpose was to assess the procedural complications of additional endovascular treatments in patients with previously coiled but recurrent aneurysms treated by two neurointerventionalists during a decade in a single center. Between 1999 and 2009, 637 intracranial aneurysms were coiled and had a clinical and angiographic follow-up at our institution. Following the first embolization, 44 aneurysms were retreated with coils and 11 were retreated a second time. Retreatment was decided when a recurrence showed at angiographic follow-up. Early retreatments, performed in the first month after an incomplete or failed initial coiling, were excluded. We retrospectively analysed the procedural complications, rebleeding, clinical and angiographic outcomes of the retreatments. No death or bleeding occurred in these 55 additional procedures. We had three periprocedural thromboembolic complications and the procedural permanent morbidity was 1.8%. Clinical and angiographic follow-ups ranged from six months to nine years (mean: 37 months, median: 36 months). Thirty-seven of the 44 retreated aneurysms (84%) showed a stable occlusion at follow-up. Seven showed a recurrence but were not retreated due to the stability of the packing. No rebleeding was observed during the follow-up period. Our results show that endovascular treatment of recurrent aneurysms is associated with a low procedural risk.

Ruptured intracranial aneurysms in the elderly

Spontaneous subarachnoid hemorrhage (SAH) is often a devastating condition and a significant cause of worldwide morbidity and mortality. Because the percentage of senior citizens is increasing in many countries and because of the increased incidence of SAH in elderly patients, ruptured intracranial aneurysm is an increasingly frequent pathology in western countries. Twenty years ago, older people were considered to have such a poor prognosis that they were frequently excluded from active treatment on the unique basis of their advanced age. Improving results published in recent studies showed that the classic fatalistic attitude associated with age and intracranial aneurysm (IA) should be reconsidered. Therefore, because of improvements in surgical results and neuro-intensive care, the appearance of interventional neuroradiology, and more aggressive rehabilitation programs, the management of ruptured IA in the elderly is changing. This article aims to review epidemiology, emphasize the specific aspects of the disease in the elderly, and present the current management of SAH in an elderly population.

Prasugrel versus clopidogrel in stent-assisted coil embolization of unruptured intracranial aneurysms

Background Thromboembolic complications are the main problem in stent-assisted coil embolization of unruptured intracranial aneurysms. The combination of aspirin and clopidogrel is generally used to decrease these complications, but some patients do not respond to clopidogrel and have a higher risk of stent thrombosis. In cardiology, clinical trials have shown that prasugrel reduced the incidence of ischaemic events in patients with acute coronary syndrome compared with clopidogrel but, according to several authors, prasugrel would produce an increased risk of cerebral haemorrhagic complications. Objective The purpose of this study was to determine whether prasugrel would be more effective than clopidogrel in reducing procedural events in patients with an unruptured aneurysm treated endovascularly with coils and stent. Materials and methods Two hundred consecutive patients with intracranial aneurysms were treated using coiling and stenting procedures. The first 100 patients were administered a dual antiplatelet of aspirin and clopidogrel, while the remaining 100 patients were administered a dual antiplatelet of aspirin and prasugrel. In each group data were collected on procedural and periprocedural haemorrhagic and ischaemic complications. Results Aneurysmal occlusion and haemorrhagic complications rates were identical in both groups. The number of thromboembolic events observed in the two groups of our study did not differ significantly, but the prasugrel group included more wide-neck aneurysms and more flow-diverted stents. Moreover, complications in the prasugrel group were more benign, explaining the significant difference in clinical outcomes between the two groups on Day 30. Conclusions Prasugrel reduces the clinical consequences of thromboembolic complications of endovascular treatment with stenting and coiling of unruptured intracranial aneurysms.

Epidemiology, genetic, natural history and clinical presentation of giant cerebral aneurysms

Giant cerebral aneurysms represent 5% of intracranial aneurysms, and become symptomatic between 40 and 70 years with a female predominance. In the paediatric population, the giant aneurysm rate is higher than in the adult population. Classified as saccular, fusiform and serpentine, the natural history of giant cerebral aneurysms is characterized by thrombosis, growth and rupture. The pathogenesis of these giant aneurysms is influenced by a number of risk factors, including genetic variables. Genome-wide association studies have identified some chromosomes highlighting candidate genes. Although these giant aneurysms can occur at the same locations as their smaller counterparts, a predilection for the cavernous location has been observed. Giant aneurysms present with symptoms caused by a mass effect depending on their location or by rupture; ischemic manifestations rarely reveal the aneurysm. If the initial clinical descriptions have been back up by imagery, the clinical context with a pertinent analysis of the risk factors remain the cornerstone for the management decisions of these lesions. Five year cumulative rupture rates for patients with giant aneurysm were 40% for those located on the anterior part of circle of Willis and 50% for those on the posterior part. The poor outcome of untreated patients justifies the therapeutic risks.

Boron Neutron Capture Enhancement (BNCE) of Fast Neutron Irradiation for Glioblastoma: Increase of Thermal Neutron Flux with Heavy Material Collimation, A Theoretical Evaluation

Despite the fact that fast neutron irradiation of glioblastoma has shown on autopsies an ability to sterilize tumors, no therapeutic windows have been found for these particles due to their toxicity toward normal brain. Therefore, the Boron Neutron Capture Enhancement (BNCE) of fast neutron beam has been suggested. This paper addresses the problem of fast neutron beam collimation, which induces a dramatic decrease of the thermal neutron flux in the depth of the tissues when smaller irradiation fields are used. Thermoluminescent dosimeter TLD-600 and TLD-700 were used to determine the thermal neutron flux within a Plexiglas phantom irradiated under the Nice Biomedical Cyclotron p(60)+Be(32) fast neutron beam. A BNCE of 4.6% in physical dose was determined for a 10×10 cm2 field, and of 10.4% for a 20×20 cm2 one. A Dose Modification Factor of 1.19 was calculated for CAL 58 glioblastoma cells irradiated thanks to the larger field. In order to increase the thermal flux in depth while shaping the beam, heavy material collimation was studied with Monte Carlo simulations using coupled FLUKA and MCNP-4A codes. The use of 20 cm width lead blocks allowed a 2 fold thermal neutron flux increase in the depth of the phantom, while shielding the fast neutron beam with a fast neutron dose transmission of 23%. Using the DMF of 1.19, a BNCE of 40% was calculated in the beam axis. This enhancement might be sufficient to open, at least theoretically, a therapeutic window.

French collaborative group series on giant intracranial aneurysms: Current management

OBJECTIVES Giant intracranial aneurysms represent a major therapeutic challenge for each surgical team. The aim of our study was to extensively review the French contemporary experience in treating giant intracranial aneurysms in order to assess the current management. PATIENTS AND METHODS This retrospective multicenter study concerned consecutive patients treated for giant intracranial aneurysms (2004-2008) in different French university hospitals (Bordeaux, Caen, Clermont-Ferrand, Lille, Lyon, Nice, Paris-Lariboisière, Rouen et Toulouse). Different variables were analyzed: the diagnostic circumstances, the initial clinical status based on the WFNS scale, aneurysmal features and exclusion procedure. At 6 months, the outcome was evaluated according to the modified Rankin Scale (mRS): favorable (mRS 0-2) and unfavorable (mRS 3-6). A multivariate logistic regression model included all the independent variables with P<0.25 in the univariate analysis (P<0.05). RESULTS A total of 79 patients with a mean age of 51.5 ± 1.6 years (median: 52 years; range: 16-79) were divided into two groups, with the ruptured group (n=26, 32.9%) significantly younger (P<0.05, Students-t-test) than the unruptured group (n=53, 67.1%). After SAH, the initial clinical status was good in 12 patients (46.2%), and in the unruptured group, the predominant diagnosis circumstance was a pseudo-tumor syndrome occurring in 22 (41.5%). The first procedure of aneurysm treatment in the global population was endovascular in 42 patients (53.1%), microsurgical in 29 (36.7%) and conservative in 8 (10.2). An immediate neurological deterioration was reported in 38 patients (48.1%) after endovascular treatment in 19 (45.2% of endovascular procedures), after miscrosurgical in 15 (51.7% of microsurgical procedures) and after conservative in 4 (the half). At 6 months, the outcome was favorable in 45 patients (57%) and after multivariate analysis, the predictive factors of favorable outcome after management of giant cerebral aneurysm were the initial good clinical status in cases of SAH (P<0.002), the endovascular treatment (P<0.005), and the absence of neurological deterioration (P<0.006). The endovascular procedure was obtained as a predictive factor because of the low risk efficacy of indirect procedures, in particular a parent vessel occlusion. CONCLUSION The overall favorable outcome rate concerned 57% of patients at 6 months despite 53.8% of poor initial clinical status in cases of rupture. The predictive factors for favorable outcome were good clinical status, endovascular treatment and the absence of postoperative neurological deterioration. Endovascular treatment should be integrated into the therapeutic armenmatarium against giant cerebral aneurysms but the durability of exclusion should be taken into account during the multidisciplinary discussion by the neurovascular team.

Modification of cerebral vascular anatomy induced by Leo stent placement depending on the site of stenting: A series of 102 cases

Background and purpose Recent studies demonstrated the capacity of stents to modify cerebral vascular anatomy. This study evaluates arterial anatomy deformation after Leo stent placement according to the stenting site and the impact on the immediate postoperative and six-month degree of aneurysmal occlusion. Materials and methods A total of 102 stents were placed against the neck of aneurysms situated in the anterior cerebral circulation. Aneurysms were classified into two groups: The first was called the distal group (n = 62) and comprised aneurysms situated in the middle cerebral and anterior communicating arteries and the second was called the proximal group (n = 40) and comprised aneurysms in other sites. The stented arterial segment was classified as deformed or non-deformed by blinded review and superimposition of anonymised films before and after stenting. The degree of occlusion was determined immediately postoperatively and at six months. Results Significantly, anatomical deformity was observed in the distal group compared to the proximal group (85% vs 28%). No significant difference was observed between the two groups in terms of postoperative degree of occlusion. At six months, a significant difference was observed between the two groups: three recurrences in the distal group vs 10 recurrences in the proximal group. Two (3%) recurrences were observed in the deformed group vs 11 (31%) recurrences in the non-deformed group. Conclusions Arterial deformity induced by stenting is even more marked for distal aneurysms. The recurrence rate is smaller when the stent placement results in an arterial anatomical change. The percentage of recurrence is lower when anatomy was amended by stent implantation.