As part of an overall effort to develop durability and damage tolerance methodology for graphite-epoxy composites, coupon specimens have been developed to measure the fundamental static fracture and subcritical growth behavior of delaminations. Two basic designs, one for the tensile opening mode (Mode I) and one for the forward shear mode (Mode II), are described. These specimens were used to characterize the behavior of two types of interfaces (0/0 and 0/90) for static fracture, constant amplitude fatigue, and spectrum fatigue. Fracture mechanics technology was applied through the principles of strain-energy release rate. Three-dimensional finite-element analyses were employed to interpret the experimental results. A simple growth law was shown to correlate the constant-amplitude and spectrum-growth data. It was found that the applied cyclic load must be nearly equal to the critical static load to obtain observable growth in the tensile opening mode. On the other hand, the graphite-epoxy delamination growth rate in the forward shear mode is comparable to the aluminum growth rate in tension, which suggests that shear is the chief subcritical growth mode for graphite-epoxy.

OBJECTIVES Postoperative cognitive decline (POCD) is a well-recognised neurological phenomenon following major surgery. Most commonly seen in elderly patients, it has direct links to increased long-term morbidity and reduced quality of life. Its incidence following open and endovascular abdominal and thoracic aneurysm surgery is unclear. The purpose of this systematic review is to collate available evidence for POCD following abdominal and thoracic aortic surgery, and to identify continuing controversies directing future research. METHODS A MEDLINE search was conducted following the recommendations of the PRISMA guidelines. Terms searched for included but were not limited to: aortic surgery, delirium, postoperative cognitive decline/dysfunction thoracic aortic surgery, abdominal aortic surgery. Reference lists were searched for additional studies. RESULTS Five observational studies were identified from the literature search. Variation in study methods, cognitive test batteries and thresholds set by the study coordinators did not allow for pooled results. In those studies that did find evidence of decline, risk was linked to age over 65 years, presence of postoperative delirium and decreased years in education. CONCLUSIONS Evidence thus far suggests that POCD can affect patients following major aortic, non-cardiothoracic as well as cardiothoracic surgery. Future research should focus on using a validated repeatable battery of cognitive tests and a single defined threshold for POCD to allow pooled analysis and more robust conclusions. Larger, adequately powered studies are required to reevaluate the effect of aortic aneurysm surgery on postoperative cognitive function.

What are the implications of reduced endovascular treatments on patients and staff at UK trusts?

Introduction The coronavirus (COVID-19) pandemic continues to affect the NHS. The Vascular and Endovascular Research Network (VERN) COvid Vascular sERvice (COVER) study has prospectively shown the significant global impact of the COVID-19 pandemic on vascular surgery. The aim of this study is to investigate the way in which this second wave has affected surgeons’ ability to treat patients with urgent vascular conditions, using contemporaneous snapshot data from 30 UK vascular centres. Methods This is a contemporary (18–28 January 2021) re-run of the Tier 1 COVER survey. This used closed and open questions, related to centres’ provision of common vascular services, threshold for treatment, imaging, screening, staff and theatre availability, multidisciplinary team input, clinics, personal protective equipment, vaccination policies and case-backlogs. The survey was disseminated to clinicians via email. A service reduction score was calculated. Results Forty-two complete responses were received from 30 vascular centres (England, Northern Ireland, Scotland and Wales). Overall, 56.7% of units are performing only urgent procedures. The threshold for abdominal aortic aneurysm (AAA) repair has increased in the majority of UK centres (60%). One in six AAA screening programmes have stopped all screening activity: 30% having a significantly reduced programme and only half running as normal. Waiting lists are increasing for AAA, lower limb revascularisation and venous disease. Conclusion Overall, these data suggest that vascular care in the NHS is facing unprecedented pressures due to COVID-19. Vascular stakeholders will have to urgently address these issues in the coming months. Study registration number ISRCTN 80453162 (registered prospectively).

modate large canal diameters and provide excellent pressurisation. TECHNIQUEThe technique involves the application of Spongostan ® foam on to a Surgicel ® mesh, which is rolled on to the Spongostan ® foam, forming a uniform cylindrical structure. The diameter of the restrictor is adjusted to the desired femoral canal diameter by increasing the thickness of the Spongostan ® foam. The restrictor is inserted into the medullary canal and guided to the appropriate position using a standard cement restrictor inserter, where it expands uniformly, creating an effective restrictor. Bone cement is applied and pressurisation commenced prior to implant insertion. The bespoke restrictor glides with minimal resistance and maintains its form during insertion. DISCUSSIONNumerous plug designs and materials are available, ranging from nonresorbable to resorbable. All restrictors should avoid intramedullary cement leakage and plug migration during cement and stem insertion to ensure adequate intramedullary pressures. The use of the Surgicel ® -Spongostan ® haemostatic restrictor overcomes some of the limitations of standard cement restrictors. These include the ability to bypass a narrow femoral isthmus, accommodate large femoral canals (particularly in revision procedures), and the flexibility of adjusting the restrictor to the desired diameter of the medullary canal, providing a bespoke cement restrictor.