A systematic review identifying outcome measures used in evaluating adults sustaining cervical spine fractures.

OBJECTIVE: To assess the outcome measures used in studies investigating cervical spine fractures in adults, with or without associated spinal cord injury, to inform development of a core outcome set. METHODS: Medline, Embase and Scopus were searched for relevant studies until May 28, 2022, without a historic limit on study date. Study characteristics, population characteristics and outcomes reported were extracted and analyzed. RESULTS: Our literature search identified 536 studies that met criteria for inclusion, involving 393,266 patients. Most studies were single center (87.3%), retrospective studies (88.9%) and involved a median of 40 patients (range 6-167,278). Treatments assessed included: surgery (55.2%), conservative (6.2%), halo immobilization (4.9%), or a mixture (33.2%). Median study duration was 84 months (range 3-564 months); the timing of clinical and/or radiological follow-up assessment after injury was reported in 56.7%. There was significant heterogeneity in outcomes used, with 79 different reported outcomes measures. Differences in use were identified between smaller/larger, retro-/prospective and single/multicenter cohorts. Over time, the use of radiological outcomes has declined with greater emphasis on patient-reported outcome measures (PROMs). Studies of conservative management were more likely to detail PROMs and mortality, whereas surgical studies reported Frankel/ASIA grade, radiological fusion, complication rates, duration of hospital stay and re-operation rates more frequently. In studies assessing the elderly population (> 65 years), use of PROMs, mortality, hospital stay and discharge destination were more common, whereas fusion was reported less often. Response rates for outcome assessments were lower in studies assessing elderly patients, and studies using PROMs. CONCLUSIONS: We have classified the various outcome measures used for patients with cervical spine fractures based on the COMET outcome taxonomy. We also described the contexts in which different outcomes are more commonly employed to help guide decision-making when designing future research endeavors

Statistical analysis plan for the Dex-CSDH trial: a randomised, double-blind, placebo-controlled trial of a 2-week course of dexamethasone for adult patients with a symptomatic chronic subdural haematoma

Abstract Background The incidence of chronic subdural haematoma (CSDH) is increasing. Although surgery remains the mainstay of management for symptomatic patients, uncertainty remains regarding the role of steroids. Hence, the Dex-CSDH trial was launched in the UK in 2015 aiming to determine whether, compared to placebo, dexamethasone can improve the 6-month functional outcome of patients with symptomatic CSDH by reducing the rate of surgical intervention and recurrence rate. Methods and design Dex-CSDH is a multi-centre, pragmatic, parallel group, double-blind, randomised trial assessing the clinical utility of a 2-week course of dexamethasone following a CSDH. Seven hundred fifty patients were randomised to either dexamethasone or placebo. The primary outcome is the modified Rankin Scale at 6 months which is dichotomised to favourable (a score of 0–3) versus unfavourable (a score of 4–6). Conclusions This paper and the accompanying additional material describe the statistical analysis plan for the trial. Trial registration ISRCTN, ISRCTN80782810. Registered on 7 November 2014. http://www.isrctn.com/ISRCTN80782810. EudraCT, 2014-004948-35. Registered on 20 March 2015. </jats:sec

Cyclical hydraulic pressure pulses reduce breakdown pressure and initiate staged fracture growth in PMMA

Using unique experimental equipment on large bench-scale samples of Polymethylmethacrylate, used in the literature as an analogue for shale, we investigate the potential benefits of applying cyclical hydraulic pressure pulses to enhance the near-well connectivity through hydraulic fracturing treatment. Under unconfined and confined stresses, equivalent to a depth of up to 530 m, we use dynamic high-resolution strain measurements from fibre optic cables, complemented by optical recordings of fracture development, and investigate the impact of cyclical hydraulic pressure pulses on the number of cycles to failure in Polymethylmethacrylate at different temperatures. Our results indicate that a significant reduction in breakdown pressure can be achieved. This suggests that cyclic pressure pulses could require lower power consumption, as well as reduced fluid injection volumes and injection rates during stimulation, which could minimise the occurrence of the largest induced seismic events. Our results show that fractures develop in stages under repeated pressure cycles. This suggests that Cyclic Fluid Pressurization Systems could be effective in managing damage build-up and increasing permeability. This is achieved by forming numerous small fractures and reducing the size and occurrence of large fracturing events that produce large seismic events. Our results offer new insight into cyclical hydraulic fracturing treatments and provide a unique data set for benchmarking numerical models of fracture initiation and propagation

Rate-dependence of the compressive and tensile strength of granites

The strength and rupture of geomaterials are integral to subsurface engineering practices, such as those required to optimise geothermal energy extraction. Of particular importance is the time- and strain-rate-dependence of material strength, which dictates the energy released upon failure, and impacts the magnitude of induced seismicity, fracture architecture and thus hydraulic conductivity and system permeability. Here, we performed a series of uniaxial compression and Brazilian tensile strength measurements at a range of deformation rates in order to constrain the impact of strain rate on the strength of G603 granite. The dense, low permeability, medium-grained granites were mechanically tested at 4 strain rates (or diametric equivalent strain rates in the case of Brazilian tests) from 10−5 to 10−2 s−1, such that sample failure was achieved in anything from below 1s at the fastest rate in tension, to over 1000s at the slowest rate in compression. The applied rates encompassed those recommended by ISRM and ASTM material testing standards for compressive and Brazilian tensile testing. We found a significant rate strengthening effect, whereby compressive and tensile strength both increased by approximately 35 % across the 4 orders of magnitude of strain rate tested. We found that the static Young's modulus remained relatively constant across this range of deformation rates, however variability was reduced at faster rates, owing to the reduced time for equilibration of the system to imposed stresses. The lower strength at slower strain rates causes smaller stress drops, indicating that rocks driven to compressive and tensile failure at slower rates release less energy upon failure. Such constraints of the strain-rate-dependence of material strength, in contrast to the use of standardised material characteristics conventionally used in Engineering Geology applications, will prove useful as we develop increasingly sophisticated strategies such as cyclic soft stimulation to access resources using less energy, whilst reducing environmental risk and producing less waste

Rate-dependence of the compressive and tensile strength of granites

The strength and rupture of geomaterials are integral to subsurface engineering practices, such as those required to optimise geothermal energy extraction. Of particular importance is the time- and strain-rate-dependence of material strength, which dictates the energy released upon failure, and impacts the magnitude of induced seismicity, fracture architecture and thus hydraulic conductivity and system permeability. Here, we performed a series of uniaxial compression and Brazilian tensile strength measurements at a range of deformation rates in order to constrain the impact of strain rate on the strength of G603 granite. The dense, low permeability, medium-grained granites were mechanically tested at 4 strain rates (or diametric equivalent strain rates in the case of Brazilian tests) from 10−5 to 10−2 s−1, such that sample failure was achieved in anything from below 1s at the fastest rate in tension, to over 1000s at the slowest rate in compression. The applied rates encompassed those recommended by ISRM and ASTM material testing standards for compressive and Brazilian tensile testing. We found a significant rate strengthening effect, whereby compressive and tensile strength both increased by approximately 35 % across the 4 orders of magnitude of strain rate tested. We found that the static Young's modulus remained relatively constant across this range of deformation rates, however variability was reduced at faster rates, owing to the reduced time for equilibration of the system to imposed stresses. The lower strength at slower strain rates causes smaller stress drops, indicating that rocks driven to compressive and tensile failure at slower rates release less energy upon failure. Such constraints of the strain-rate-dependence of material strength, in contrast to the use of standardised material characteristics conventionally used in Engineering Geology applications, will prove useful as we develop increasingly sophisticated strategies such as cyclic soft stimulation to access resources using less energy, whilst reducing environmental risk and producing less waste.</p

Study Protocol on Defining Core Outcomes and Data Elements in Chronic Subdural Haematoma

Abstract BACKGROUND Core Outcome Sets (COSs) are necessary to standardize reporting in research studies. This is urgently required in the field of chronic subdural hematoma (CSDH), one of the most common disease entities managed in neurosurgery and the topic of several recent trials. To complement the development of a COS, a standardized definition and baseline Data Elements (DEs) to be collected in CSDH patients, would further improve study quality and comparability in this heterogeneous population. OBJECTIVE To, first, define a standardized COS for reporting in all future CSDH studies; and, second, to identify a unified CSDH Definition and set of DEs for reporting in future CSDH studies. METHODS The overall study design includes a Delphi survey process among 150 respondents from 2 main stakeholder groups: healthcare professionals or researchers (HCPRs) and Patients or carers. HCPR, patients and carers will all be invited to complete the survey on the COS, only the HCPR survey will include questions on definition and DE. EXPECTED OUTCOMES It is expected that the COS, definition, and DE will be developed through this Delphi survey and that these can be applied in future CSDH studies. This is necessary to help align future research studies on CSDH and to understand the effects of different treatments on patient function and recovery. DISCUSSION This Delphi survey should result in consensus on a COS and a standardized CSDH Definition and DEs to be used in future CSDH studies. </jats:sec

Evaluation of nationwide referral pathways, investigation and treatment of suspected cauda equina syndrome in the United Kingdom.

Purpose: Cauda equina syndrome (CES) is a spinal emergency with clinical symptoms and signs that have low diagnostic accuracy. National guidelines in the United Kingdom (UK) state that all patients should undergo an MRI prior to referral to specialist spinal units and surgery should be performed at the earliest opportunity. We aimed to evaluate the current practice of investigating and treating suspected CES in the UK. Materials and Methods: A retrospective, multicentre observational study of the investigation and management of patients with suspected CES was conducted across the UK, including all patients referred to a spinal unit over 6 months between 1st October 2016 and 31st March 2017. Results: A total of 28 UK spinal units submitted data on 4441 referrals. Over half of referrals were made without any previous imaging (n = 2572, 57.9%). Of all referrals, 695 underwent surgical decompression (15.6%). The majority of referrals were made out-of-hours (n = 2229/3517, 63.4%). Patient location and pre-referral imaging were not associated with time intervals from symptom onset or presentation to decompression. Patients investigated outside of the spinal unit experienced longer time intervals from referral to undergoing the MRI scan. Conclusions: This is the largest known study of the investigation and management of suspected CES. We found that the majority of referrals were made without adequate investigations. Most patients were referred out-of-hours and many were transferred for an MRI without subsequently requiring surgery. Adherence to guidelines would reduce the number of referrals to spinal services by 72% and reduce the number of patient transfers by 79%

Estimating geological CO2 storage security to deliver on climate mitigation

Carbon capture and storage (CCS) can help nations meet their Paris CO2 reduction commitments cost-effectively. However, lack of confidence in geologic CO2 storage security remains a barrier to CCS implementation. Here we present a numerical program that calculates CO2 storage security and leakage to the atmosphere over 10,000 years. This combines quantitative estimates of geological subsurface CO2 retention, and of surface CO2 leakage. We calculate that realistically well-regulated storage in regions with moderate well densities has a 50% probability that leakage remains below 0.0008% per year, with over 98% of the injected CO2 retained in the subsurface over 10,000 years. An unrealistic scenario, where CO2 storage is inadequately regulated, estimates that more than 78% will be retained over 10,000 years. Our modelling results suggest that geological storage of CO2 can be a secure climate change mitigation option, but we note that long-term behaviour of CO2 in the subsurface remains a key uncertainty