Introducing navigated transcranial magnetic stimulation as a refined brain mapping methodology

A major intrinsic limitation of transcranial magnetic stimulation (TMS) to map the human brain lies in the unclear relationship between the position of the stimulating coil on the scalp and the underlying stimulated cortex. The relationship between structure and function as the major feature constituting a brain mapping modality can therefore not be established. Recent advances in image processing allowed us to refine TMS by combining magnetic resonance imaging (MRI) modalities with TMS using a neuronavigation system to measure the position of the stimulating coil and map this position onto a MRI data set. This technique has several advantages over recent TMS mapping strategies. The position of the coil on the scalp can be held constant as verified by real time visual guidance. When evaluating higher cortical functions, the relationship between underlying cortical anatomy and the scalp stimulation site can be accurately assessed. Cortical motor output maps can be easily obtained for preoperative planning and decision making for mass lesions near rolandic cortex in patients. In conclusion, navigated TMS is a reliable alternative for localizing cortical functions and therefore may be a useful adjunct or in selected patients even a helpful alternative to other functional neuroimaging methods. Electronic Publication     

Staphylococcus aureus bacteremia after thermal injury: The clinical impact of methicillin resistance

Objective

To evaluate the impact of methicillin resistance in Staphylococcus aureus bacteremia (SAB) on mortality and length of stay in burn patients.

Design

Retrospective cohort study.

Setting

A 750-bed tertiary care university hospital in Cologne, Germany.

Patients

Patients registered in the database of the burn intensive care unit (BICU) between 1989 and 2009 with complete data sets (n = 1688).

Results

Over the 21-year study period, 74 patients with SAB were identified; 33 patients had methicillin-resistant S. aureus (MRSA) and 41 methicillin-susceptible S. aureus (MSSA). Comparing the MRSA with the MSSA population the following parameters were significantly different in the univariate analysis: BMI (27.2 kg/m² vs. 23.6 kg/m²; P = 0.05), extent of deep partial thickness burns (17.8% vs. 9.0% of total body surface area; P = 0.007), antibiotic requirement on admission (45.5% vs. 22.0%; P = 0.046), median length of hospitalization prior SAB (24 days vs. 7 days; P < 0.001), packed red blood cells administration (47.6 units vs. 26.1 units; P = 0.003), intubation requirement (100% vs. 80.5%; P = 0.007), intubation period (43.5 days vs. 26.8 days; P = 0.008), catecholamine requirement (90.9% vs. 61.0%; P = 0.004), sepsis (60.6% vs. 34.1%; P = 0.035) and organ failures (81.8% vs. 39.0%; P < 0.001). Regarding outcome parameters, methicillin resistance was not significantly related with mortality (adjusted OR 1.55, 95% CI 0.56–4.28; P = 0.40) and length of BICU stay after SAB (Kaplan–Meier analysis log-rank test P = 0.32; Cox's proportional hazards regression HR 1.22, 95% CI 0.65–2.27, P = 0.535) in the univariate and multivariate analyses.

Conclusion

Our data suggest that methicillin resistance is not associated with significant increases in mortality and length of BICU stay among burn patients with SAB.     

Predictors of mortality following primary hip and knee replacement in the aged: A single-center analysis of 1,998 primary hip and knee replacements for primary osteoarthritis

Background and purpose High age is associated with increased postoperative mortality, but the factors that predict mortality in older hip and knee replacement recipients are not known.

Methods Preoperative clinical and operative data on 1,998 primary total hip and knee replacements performed for osteoarthritis in patients aged ≥ 75 years in a single institution were collected from a joint replacement database and compoared with mortality data. Average follow-up was 4.2 (2.2–7.6) years for the patients who survived. Factors associated with mortality were analyzed using Cox regression analysis, with adjustment for age, sex, operated joint, laterality, and anesthesiological risk score.

Results Mortality was 0.15% at 30 days, 0.35% at 90 days, 1.60% at 1 year, 7.6% at 3 years, and 16% at 5 years, and was similar following hip and knee replacement. Higher age, male sex, American Society of Anesthesiologists risk score of > 2, use of walking aids, preoperative walking restriction (inability to walk or ability to walk indoors only, compared to ability to walk > 1 km), poor clinical condition preoperatively (based on clinical hip and knee scores or clinical severity of osteoarthritis), preoperative anemia, severe renal insufficiency, and use of blood transfusions were associated with higher mortality. High body mass index had a protective effect in patients after hip replacement.

Interpretation Postoperative mortality is low in healthy old joint replacement recipients. Comorbidities and functional limitations preoperatively are associated with higher mortality and warrant careful consideration before proceeding with joint replacement surgery.     

Bone Mass,Bone Microstructure and Biomechanics in Patients with Hand Osteoarthritis

The impact of primary hand osteoarthritis (HOA) on bone mass, microstructure, and biomechanics in the affected skeletal regions is largely unknown. HOA patients and healthy controls (HCs) underwent high-resolution peripheral quantitative computed tomography (HR-pQCT). We measured total, trabecular, and cortical volumetric bone mineral densities (vBMDs), microstructural attributes, and performed micro–finite element analysis for bone strength. Failure load and scaled multivariate outcome matrices from distal radius and second metacarpal (MCP2) head measurements were analyzed using multiple linear regression adjusting for age, sex, and functional status and reported as adjusted Z-score differences for total and direct effects. A total of 105 subjects were included (76 HC: 46 women, 30 men; 29 HOA: 23 women, six men). After adjustment, HOA was associated with significant changes in the multivariate outcome matrix from the MCP2 head (p < .001) (explained by an increase in cortical vBMD (Δz = 1.07, p = .02) and reduction in the trabecular vBMD (Δz = −0.07, p = .09). Distal radius analysis did not show an overall effect of HOA; however, there was a gender-study group interaction (p = .044) explained by reduced trabecular vBMD in males (Δz = −1.23, p = .02). HOA was associated with lower failure load (−514 N; 95%CI, −1018 to −9; p = 0.05) apparent in males after adjustment for functional status. HOA is associated with reduced trabecular and increased cortical vBMD in the MCP2 head and a reduction in radial trabecular vBMD and bone strength in males. Further investigations of gender-specific changes of bone architecture in HOA are warranted. © 2020 The Authors. Journal of Bone and Mineral Research published by American Society for Bone and Mineral Research.     

Monitoring of gliomas in vivo by diffusion MRI and 1H MRS during gene therapy‐induced apoptosis: interrelationships between water diffusion and mobile lipids

The measurement of water diffusion by diffusion‐weighted MRI (DWI) in vivo offers a non‐invasive method for assessing tissue responses to anti‐cancer therapies. The pathway of cell death after anti‐cancer treatment is often apoptosis, which leads to accumulation of mobile lipids detectable by ¹H MRS in vivo. However, it is not known how these discrete MR markers of cell death relate to each other. In a rodent tumour model [i.e. ganciclovir‐treated herpes simplex thymidine kinase (HSV‐tk) gene‐transfected BT4C gliomas], we studied the interrelationships between water diffusion (Trace{D}) and mobile lipids during apoptosis. Water diffusion and water‐referenced concentrations of mobile lipids showed clearly increasing and interconnected trends during treatment. Of the accumulating ¹H MRS‐visible lipids, the fatty acid ? CH ?CH ? groups and cholesterol compounds showed the strongest associations with water diffusion (r² = 0.30; P < 0.05 and r² = 0.48; P < 0.01, respectively). These results indicate that the tumour histopathology and apoptotic processes during tumour shrinkage can be interrelated in vivo by DWI of tissue water and ¹H MRS of mobile lipids, respectively. However, there is considerable individual variation in the associations, particularly at the end of the treatment period, and in the relative compositions of the accumulating NMR‐visible lipids. The findings suggest that the assessment of individual treatment response in vivo may benefit from combining DWI and ¹H MRS. Absolute and relative changes in mobile lipids may indicate initiation of tumour shrinkage even when changes in tissue water diffusion are still small. Conversely, greatly increased water diffusion probably indicates that substantial cell decomposition has taken place in the tumour tissue when the ¹H MRS resonances of mobile lipids alone can no longer give a reliable estimate of tissue conditions. Copyright © 2008 John Wiley & Sons, Ltd.     

Prediction of clinical outcomes in Crohn’s disease by using confocal laser endomicroscopy: results from a prospective multicenter study

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