Comparison of the use of ventricular access devices and ventriculosubgaleal shunts in posthaemorrhagic hydrocephalus: systematic review and meta-analysis.

INTRODUCTION: Ventricular access devices (VAD) and ventriculosubgaleal shunts (VSGS) are currently both used as temporising devices to affect CSF drainage in neonatal posthaemorrhagic hydrocephalus (PHH), without clear evidence of superiority of either procedure. In this systematic review and meta-analysis, we compared the VSGS and VAD regarding complication rates, ventriculoperitoneal shunt conversion and infection rates, and mortality and long-term disability. METHODS: The review was registered with the PROSPERO international prospective register of systematic reviews (registration number CRD42015019750) and was conducted in accordance with PRISMA guidelines. RESULTS AND CONCLUSIONS: The literature search of five databases identified 338 publications, of which 5 met the inclusion criteria. All were retrospective cohort studies (evidence class 3b and 4). A significantly lower proportion of patients with a VSGS required CSF tapping compared to patients with a VAD (log OR -4.43, 95% CI -6.14 to -2.72). No other significant differences between the VAD and VSGS were identified in their rates of infection (log OR 0.03, 95% CI -0.77 to 0.84), obstruction (log OR 1.25, 95% CI -0.21 to 2.71), ventriculoperitoneal shunt dependence (log OR -0.06, 95% CI -0.93 to 0.82), subsequent shunt infection (log OR 0.23, 95% CI -0.61 to 1.06), mortality (log OR 0.37, 95% CI -0.95 to 1.70) or long-term disability (p = 0.9). In all studies, there was a lack of standardised criteria, variations between surgeons in heterogeneous cohorts of limited sample size and a lack of neurodevelopmental follow-up. This affirms the importance of an ongoing multicentre, prospective pilot study comparing these two temporising procedures to enable a more robust comparison.

Mechanisms for collective inversion-symmetry breaking in dabconium perovskite ferroelectrics.

Dabconium hybrid perovskites include a number of recently-discovered ferroelectric phases with large spontaneous polarisations. The origin of ferroelectric response has been rationalised in general terms in the context of hydrogen bonding, covalency, and strain coupling. Here we use a combination of simple theory, Monte Carlo simulations, and density functional theory calculations to assess the ability of these microscopic ingredients-together with the always-present through-space dipolar coupling-to account for the emergence of polarisation in these particular systems whilst not in other hybrid perovskites. Our key result is that the combination of A-site polarity, preferred orientation along 〈111〉 directions, and ferroelastic strain coupling drives precisely the ferroelectric transition observed experimentally. We rationalise the absence of polarisation in many hybrid perovskites, and arrive at a set of design rules for generating FE examples beyond the dabconium family alone.

Corrigendum: Age-Related Vestibular Loss: Current Understanding and Future Research Directions.

[This corrects the article on p. 231 in vol. 7, PMID: 28066316.].

Reporting of patient-reported health-related quality of life in adults with diffuse low-grade glioma: a systematic review.

BACKGROUND: Patient-reported health-related quality of life (HRQoL) analysis can provide important information for managing the balance between treatment benefits and treatment-related adverse effects on quality of life (QoL). This systematic review sought to identify the range of HRQoL measures used for patients with diffuse hemispheric WHO grade II glioma (DLGG) and assess the quality of HRQoL reporting. METHODS: This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Databases were searched for full-text English articles reporting HRQoL outcomes in adult patients with DLGG. RESULTS: Eleven different QoL measures were used across the 26 included studies, none of which has been validated in patients with DLGG. Heterogeneity of study design prevented pooled analysis of data investigating the effect of interventions or establishing long-term HRQoL. Low rates of participation at baseline (mean: 64.0%) and high rates of subsequent dropout (2.1% per month) were identified. Five studies gave statistical methods to deal with missing data or provided evidence of clinical significance of HRQoL results. CONCLUSIONS: The results demonstrate a paucity and heterogeneity of reporting of HRQoL in the DLGG literature, highlighting the need for a standardized assessment schedule and set of validated quality-of-life measures for future studies.