Has the introduction of antibiotic-impregnated external ventricular drain catheters changed the nature of the microorganisms cultured in patients with drain-related infection? A single neurosurgical centre's experience.

BACKGROUND: The introduction of antibiotic-impregnated catheters (AICs) has significantly reduced external ventricular drain (EVD) infection rates, inhibiting in particular Gram-positive microbial infection. There is a theoretical increased risk of selection of resistant and Gram-negative microorganisms. The aim of this study is to look at the impact of the introduction of AICs on microorganism susceptibility of infected EVDs and to determine whether the use of such devices results in shift from Gram-positive to Gram-negative microorganisms. A secondary aim is to determine if a change in routine empiric antimicrobial therapy is required because of a change in the microorganism(s) causing infection. METHODS: Retrospective analysis of EVDs inserted as a primary procedure or part of a concomitant neurosurgical procedure in 2006 (pre-AIC) and 2012 (post-AIC Codman Bactiseal(©) impregnated with clindamycin 0.15% and rifampicin 0.054%). EVD-related infection was defined as a cerebral spinal fluid sample with a positive culture with some patients having one or more microorganisms infecting the same EVD at the same time. Sixty-five EVDs over 843 days and 66 EVDs over 619 days were inserted respectively in each cohort. RESULTS: In 2006, 9 of 35 patients developed EVD-related infection and 13 microorganisms were cultured; 8 of which were Gram-positive and 4 Gram-negative. Four of 49 patients developed EVD-related infection in 2012 and six microorganisms were cultured; four Gram-positive and two Gram-negative. The cumulative incidence of EVDs becoming infected is 18.5% (12/65) and 6.1% (4/66; p = 0.03) in 2012. The EVD-associated infection rate was 14.2 per 1000 EVD days and 6.5 per 1000 EVD days in 2012. There was no change in mortality. CONCLUSIONS: The study demonstrates that within a single neurosurgical centre there have been neither changes in susceptibility of microorganisms nor a change from predominately Gram-positive to Gram-negative microorganisms infecting EVDs following the switch to AIC. The infection rate has significantly reduced due to change in catheter type.

The longitudinal profile of CSF markers during external lumbar drainage.

BACKGROUND: External lumbar drainage (ELD) is known as a good predictor of favourable outcome in shunting patients suffering from idiopathic normal pressure hydrocephalus (iNPH). METHODS: Eleven patients suffering from iNPH had a lumbar drain (LD) inserted for 72 h and participated in a research study to quantify any improvement in their clinical symptoms. The lumbar cerebrospinal fluid (CSF) levels of lactate, 8-isoprostane, vascular endothelial growth factor (VEGF), glial fibrillar acidic protein (GFAP), neurofilament (heavy chain) protein (NF (h)), Abeta(1-42) (beta-amyloid) and total tau were assayed samples from all three time points. RESULTS: The concentrations of lactate, VEGF, GFAP and tau increased significantly during the 72 h of drainage. There were also increases in 8-isoprostane and Abeta(1-42) (non significant). The concentration of NF (h) was reduced significantly following 72 h of drainage. There was a significant positive correlation between Abeta(1-42) and total tau in the first sample. GFAP was negatively correlated in a significant fashion with both Abeta(1-42) and total tau. NF (h) was negatively correlated with VEGF. CONCLUSION: Evidence is provided that ELD is producing measurable changes in the CSF composition of patients with iNPH. The present paper discusses how such changes may be implicated in the pathophysiology of the condition.

Does conservative management for brain stem cavernomas have better long-term outcome?

There has been a controversy in the last 15 years on the correct management of brain stem cavernomas. We have reviewed our experience of the last 10 years in a single Institution and reviewed related literature published in the last 15 years. We recorded the demographics, clinical presentation, rebleeding episodes, incidence of neurological events and outcome assessed by recording the change of the modified Rankin scale in 21 cases. Univariate analysis was applied to test the effect of demographics, and presentation on the incidence and timing of rebleeding, chance of having a new neurological event, the number of subsequent neurological events and outcomes. Six cases were treated with surgery and 15 cases were managed conservatively. We obtained follow-up data in 20 patients (95%). Mean follow-up period was 79.7 months (range: 6-244, median 70 months). There were 0.05 rebleeding events per patient-year and 0.1 episodes of neurological deterioration per patient-year. No mortality was noted in either the surgical or the non-surgical group. Three of the six surgical cases had a reoperation. The outcome was improved in one patient, unchanged in 1, and worse in 3 surgical patients. In the case of conservative management the outcome was improved in two patients, unchanged in five patients, and worse in eight patients. Outcome was worse in the case of multiple cavernomas (p = 0.012). Our findings suggest that conservative management may be appropriate in individual cases when compared with surgery, but this difference was not statistically significant enough in order to support a change in practice. The natural history of brain stem cavernomas appears more benign than previously thought.

Evolution in practice: how has British neurosurgery changed in the last 10 years?

INTRODUCTION: Neurosurgery is a fast-evolving surgical subspecialty driven by technological advances, socio-economic factors and patient expectations. In this study, we have compared the work-load volume in a single institution in the years of 1994 and 2004 and commented on the possible reasons for the changes and the impacts they may have for the future. PATIENTS AND METHODS: A retrospective, log-book review of all operations performed in the years 1994 and 2004 in a single, tertiary, neurosurgical centre was performed. RESULTS: Neurosurgical practice has evolved over this period. Current practice has moved away from clipping of aneurysms and towards coil embolisation performed by interventional radiologists. Electrode stimulation of deep brain regions for movement disorders is the current practice, whereas 10 years ago the same disorders were dealt with by lesioning of the relevant regions. In spinal neurosurgery, instrumentation is increasingly favoured currently. In the field of neuro-oncology, current practice favours minimal access to the target area by the use of stereotactic localisation. CONCLUSIONS: Changes were most pronounced in the subspecialties of vascular, functional and spinal neurosurgery within this 10-year period. Knowledge of such dynamics is valuable in health resource management as well as planning for neurosurgical training programmes.

A comparison of magnetic resonance angiography and constructive interference in steady state-three-dimensional Fourier transformation magnetic resonance imaging in patients with hemifacial spasm.

Although the decision to perform a microvascular decompression of the facial nerve is based on clinical history and assessment, preoperative imaging of the neurovascular relationships at the REZ is important to exclude a non-vascular cause or identify dolichoectatic vessels that might influence the surgical approach. We designed the current study to compare the specificity and sensitivity of gadolinium-enhanced 3D fast inflow with steady state precession (FISP) MRA with CISS. The imaging findings of 47 patients that had microvascular decompression for hemifacial spasm were retrospectively reviewed in a single blind fashion. The 47 non-symptomatic sides served as controls. Neurovascular contact could be seen in 13/47 (27.6%) in routine T2 axial scans, in 22/35 (62.8%) in high resolution T2W, in 18/34 (52.9%) in the case of MRA, and in all cases (13) when the CISS sequence was used. This study demonstrated 56.2% sensitivity and 50% specificity for MRA with gadolinium enhancement, whereas the CISS sequence can achieve a sensitivity of 100% in correctly demonstrating neurovascular compression in HFS. Overall accuracy of the two methods was 55.8 and 100% for MRA and CISS, respectively. The CISS sequence is superior in identifying neurovascular compression when compared with MRA. Preoperative knowledge of the compressing vessel has counselling implications and the higher risk of complications should be communicated to the patient. Due to cost and time implications we suggest that MR-CISS imaging replace the enhanced MRA sequence in the detailed preoperative MR assessment of hemifacial spasm.