Biomechanical Analysis of Reducing Sacroiliac Joint Shear Load by Optimization of Pelvic Muscle and Ligament Forces

Effective stabilization of the sacroiliac joints (SIJ) is essential, since spinal loading is transferred via the SIJ to the coxal bones, and further to the legs. We performed a biomechanical analysis of SIJ stability in terms of reduced SIJ shear force in standing posture using a validated static 3-D simulation model. This model contained 100 muscle elements, 8 ligaments, and 8 joints in trunk, pelvis, and upper legs. Initially, the model was set up to minimize the maximum muscle stress. In this situation, the trunk load was mainly balanced between the coxal bones by vertical SIJ shear force. An imposed reduction of the vertical SIJ shear by 20% resulted in 70% increase of SIJ compression force due to activation of hip flexors and counteracting hip extensors. Another 20% reduction of the vertical SIJ shear force resulted in further increase of SIJ compression force by 400%, due to activation of the transversely oriented M. transversus abdominis and pelvic floor muscles. The M. transversus abdominis crosses the SIJ and clamps the sacrum between the coxal bones. Moreover, the pelvic floor muscles oppose lateral movement of the coxal bones, which stabilizes the position of the sacrum between the coxal bones (the pelvic arc). Our results suggest that training of the M. transversus abdominis and the pelvic floor muscles could help to relieve SI-joint related pelvic pain

Risk factors for pelvic girdle pain postpartum and pregnancy related low back pain postpartum:a systematic review and meta-analysis

Contains fulltext : 221001.pdf (Publisher’s version ) (Closed access)BACKGROUND: Although pelvic girdle pain postpartum and pregnancy related low back pain postpartum (combined and named PGPP in this study) have a natural favourable course, there is a subgroup of women who have persistent complaints. The objective of this study was to identify personal-, (pre)pregnancy-, obstetric-, and child related risk factors on PGPP by means of a systematic literature review and meta-analysis. METHODS: Literature searches of PubMed, EMBASE, CINAHL and Cochrane up to October 2018 were conducted. Prospective cohort studies in English or Dutch describing three or more risk factors for PGPP were included. We assessed articles for inclusion and risk of bias. Studies with high risk of bias were excluded from data extraction. Data was extracted and checked for accuracy confirming to the CHARMS-checklist. Homogeneous variables were pooled. RESULTS: Twelve full text studies were assessed. Seven studies were excluded due to high risk of bias. Data was extracted from five studies. Multivariate analysis was not possible due to heterogeneity in included risk factors as well as outcome measures on risk factor per study. Pooled univariate significant risk factors on PGPP were: a history of low back pain, pre-pregnancy body mass index >25, pelvic girdle pain in pregnancy, depression in pregnancy, and a heavy workload in pregnancy. No significant obstetric and child related risk factors were reported. CONCLUSIONS: Risk factors on PGPP have been identified. Since multivariate analysis was not possible the outcome should be treated with care, because interaction between risk factors could not be analysed

Boomwortels: de verschillende ondergrondse strategieën van bomen

Planten kunnen zich aanpassen aan veranderende omstandigheden. Zo kunnen bomen grotere bladeren maken in de schaduw, of dikkere bij droogte. Hoe en of een boom ook de wortels kan aanpassen, is veel min- der duidelijk. Wij keken daarom in een onderzoek of je bij verschillende boomsoorten en onder verschillende omstandigheden andere wortels aan- treft in de bodem

Local quantification of mesoporous silica microspheres using multiscale electron tomography and lattice Boltzmann simulations

The multiscale pore structure of mesoporous silica microspheres plays an important role for tuning mass transfer kinetics in technological applications such as liquid chromatography. While local analysis of a pore network in such materials has been previously achieved, multiscale quantification of microspheres down to the nanometer scale pore level is still lacking. Here we demonstrate for the first time, by combining low convergence angle scanning transmission electron microscopy tomography (LC-STEM tomography) with image analysis and lattice Boltzmann simulations, that the multiscale pore network of commercial mesoporous silica microspheres can be quantified. This includes comparing the local tortuosity and intraparticle diffusion coefficients between different regions within the same microsphere. The results, spanning more than two orders of magnitude between nanostructures and entire object, are in good agreement with bulk characterization techniques such as nitrogen gas physisorption and add valuable local information for tuning mass transfer behavior (in liquid chromatography or catalysis) on the single microsphere level

Clinical consequences of consecutive self-expanding transcatheter heart valve iterations

OBJECTIVE: To compare early clinical outcomes after transcatheter aortic valve implantation (TAVI) with three consecutive generations of self-expanding valves (SEVs). METHODS: Clinical endpoints of consecutive patients who underwent TAVI with CoreValve, Evolut R or Evolut PRO were included in a prospective database. RESULTS: TAVI was performed with CoreValve (n = 116), Evolut R (n = 160) or Evolut PRO (n = 92). Evolut R and Evolut PRO showed a tendency towards lower permanent pacemaker implantation (PPI) rates compared to CoreValve (CoreValve 27% vs Evolut R 16% vs Evolut PRO 18%, p = 0.091). By multivariable regression analysis CoreValve had a significantly higher risk for PPI (odds ratio (OR) 2.79, 95% confidence interval (CI) 1.31–5.94, p = 0.008) compared to Evolut R, while Evolut R and PRO were similar. Severe paravalvular leakage (PVL) occurred only with CoreValve, but no significant difference was observed in moderate PVL (10% vs 8% vs 6%, p = 0.49). CoreValve had a tendency towards a higher risk for more-than-mild PVL as compared with the Evolut platform (R + PRO) (OR 2.46, 95% CI 0.98–6.16, p = 0.055). No significant differences in all-cause mortality (7% vs 4% vs 1%, p = 0.10), stroke (6% vs 3% vs 2%, p = 0.21) or major vascular complications (10% vs 12% vs 4%, p = 0.14) were observed. CONCLUSIONS: TAVI with self-expanding valves was safe, and device iterations may result in a lower need for PPI. More-than-mild PVL seemed to occur less often with repositionable technology. SUPPLEMENTARY INFORMATION: The online version of this article (10.1007/s12471-021-01568-5) contains supplementary material, which is available to authorized users

Incidence, determinants and consequences of delirium in older patients after transcatheter aortic valve implantation

Background: delirium is an event leading to negative health outcomes and increased mortality in patients. The aim of this study is to investigate the incidence, determinants and consequences of post-operative delirium (POD) in older patients undergoing transcatheter aortic valve implantation (TAVI). Methods: The TAVI Care and Cure program is a prospective, observational registry in patients referred for TAVI at Erasmus University Medical Centre. The presence of delirium was evaluated by daily clinical assessment by a geriatrician pre- and up to 3 days post-TAVI. Mortality data were obtained from the Dutch Civil Registry. Results: A total of 543 patients underwent TAVI between January 2014 and December 2017. Overall, the incidence of POD was 14% (75/543 patients) but declined from 18% in 2014 to 7% in 2017 (P = 0.009). Patients who developed POD were older (81.9 ± 5.8 versus 78.6 ± 8.3 years, P < 0.001), had higher prevalence of renal dysfunction and prior stroke (54% versus 40%, P = 0.02; 31% versus 18%, P = 0.01) and were more often frail (32% versus 25%, P = 0.02). From a procedural perspective, general anesthesia (odds ratios (OR), 2.31; 95% CI, 1.40–3.83; P = 0.001), non-transfemoral access (OR, 2.37; 95% CI, 1.20–4.70; P = 0.01) and longer procedural time (OR, 1.01; 95% CI, 1.01–1.02; P < 0.001) were significantly associated with POD. One-year survival rate was 68% among patients who had suffered a POD and was 85% in patients without a POD (hazard ratio’s 1.8 (95% CI 1.01–3.10), P = 0.045). Conclusion: POD frequently occurs after TAVI and is associated with increased mortality. It might be speculated that patient selection and the minimalistic approach of TAVI may reduce the frequency of delirium

Pelvic floor muscle function in a general female population in relation with age and parity and the relation between voluntary and involuntary contractions of the pelvic floor musculature

Contains fulltext : 80525.pdf (publisher's version ) (Closed access

Short-term changes of blood pressure and aortic stiffness in older patients after transcatheter aortic valve implantation

Background: Both aortic valve stenosis and aortic stiffness are moderators of arterio ventricular coupling and independent predictors of cardiovascular morbidity and mortality. Studies on the effect of transcatheter aortic valve implantation (TAVI) on aortic functional properties are limited. We performed a study to investigate the possible short-term changes in aortic stiffness and other aortic functional properties after TAVI in older patients. Methods: TAVI Care&Cure is an observational ongoing study including consecutive patients undergoing a TAVI procedure. Central and peripheral hemodynamic measurements were measured non invasively 1 day before (T-1) and 1 day after (T+1) TAVI using a validated oscillometric method using a br