Three-dimensional hindfoot alignment measurements based on biplanar radiographs: comparison with standard radiographic measurements

Objective: To establish a hindfoot alignment measurement technique based on low-dose biplanar radiographs and compare with hindfoot alignment measurements on long axial view radiographs, which is the current reference standard. Materials and methods: Long axial view radiographs and low-dose biplanar radiographs of a phantom consisting of a human foot skeleton embedded in acrylic glass (phantom A) and a plastic model of a human foot in three different hindfoot positions (phantoms B1-B3) were imaged in different foot positions (20° internal to 20° external rotation). Two independent readers measured hindfoot alignment on long axial view radiographs and performed 3D hindfoot alignment measurements based on biplanar radiographs on two different occasions. Time for three-dimensional (3D) measurements was determined. Intraclass correlation coefficients (ICC) were calculated. Results: Hindfoot alignment measurements on long axial view radiographs were characterized by a large positional variation, with a range of 14°/13° valgus to 22°/27° varus (reader 1/2 for phantom A), whereas the range of 3D hindfoot alignment measurements was 7.3°/6.0° to 9.0°/10.5° varus (reader 1/2 for phantom A), with a mean and standard deviation of 8.1° ± 0.6/8.7° ± 1.4 respectively. Interobserver agreement was high (ICC = 0.926 for phantom A, and ICC = 0.886 for phantoms B1-B3), and agreement between different readouts was high (ICC = 0.895-0.995 for reader 1, and ICC = 0.987-0.994 for reader 2) for 3D measurements. Mean duration of 3D measurements was 84 ± 15/113 ± 15s for reader 1/2. Conclusion: Three-dimensional hindfoot alignment measurements based on biplanar radiographs were independent of foot positioning during image acquisition and reader independent. In this phantom study, the 3D measurements were substantially more precise than the standard radiographic measurement

CT-guided cervical nerve root injections: comparing the immediate post-injection anesthetic-related effects of the transforaminal injection with a new indirect technique

Objective: To describe an "indirect” cervical nerve root injection technique with a dorsal approach that should carry less inherent risk than the "direct” cervical transforaminal injection approach, and to compare the immediate post-injection results of the two procedures. Materials and methods: The indirect and direct cervical nerve root injection procedures are described in detail. Fifty-three consecutive patients receiving the indirect nerve root injections during 2009-2010 were age- and gender-matched to 53 patients who underwent direct transforaminal nerve root injections performed in 2006. Pain level data were collected immediately before and 20-30min after each procedure. The percentages of pain change in the two groups were compared using the unpaired Student'st test. Results: Fifty-two men (mean age 49) and 54 women (mean age 55) were included. The mean percentage of pain reduction for patients receiving indirect nerve root injections was 38.4% and for those undergoing the direct nerve root injections approach it was 43.2%. This was not significantly different (P = 0.455). No immediate or late adverse effects were reported after either injection procedure. Conclusions: The indirect cervical nerve root injection procedure is a potentially safer alternative to direct cervical transforaminal nerve root injections. The short-term pain reduction is similar using the two injection method

A comprehensive environmental assessment of petrochemical solvent production

Background, aim, and scope: Organic solvents are used in large quantities in the chemical, metal and electronics industries as well as in many consumer products, such as coatings or paints, and are therefore among the most important chemicals. The petrochemical production of organic solvents is a relevant environmental issue because fossil resources are needed (crude oil and natural gas), synthesis processes are energy-intensive and cause considerable amounts of emissions. So far, comprehensive data on the environmental impact are rather scarce. The aim of this paper is to therefore present a systematical environmental assessment of the main petrochemical solvent production routes using the Life Cycle Assessment (LCA) method. Methods: Fifty organic solvents were selected covering the most important representatives from the various chemical groups (e.g., alcohols, esters, ketones). To conduct the LCA, 40 new Life Cycle Inventories (LCI) were established and existing LCI were improved. The petrochemical solvent production was structured into four production routes. In these production routes, the single chemical unit processes (e.g. esterification, carbonylation or hydrogenation) were analyzed in order to determine characteristic environmental impacts. Results and discussion: The four solvent production routes including the unit processes and intermediates are presented. Additionally, energy profiles of these production routes are shown using the Cumulative Primary Energy Demand (CED) as an indicator for the environmental impact. The results were cross-checked with the Global Warming Potential and the Eco-indicator 99 method and good correlations were found. Processes that show high environmental impacts are the dehydration of butylene glycol to tetrahydrofuran, the carbonylation of methanol to methyl formate, the hydrogenation of acetone to methyl isobutyl ketone, and the Reppe synthesis of formaldehyd/acetylene to butylene glycol. Based on the energy profiles, ranges of environmental impacts are determined for all unit processes. On the one hand, esterification and alkylation processes cause high CED values because complex ancillaries are needed and hydroformylation and carbonylation processes are energy-intensive. On the other hand, in hydration, hydrogenation, hydrolysis, and oxidation processes, ancillaries with low CED are added to the chemical structure that result in low CED ranges for these unit processes. Dehydrogenation and molecular sieve separation processes seem to be energy efficient and no ancillaries are required. Therefore, these unit processes cause the lowest CED values. Perspectives: Subject of further research in this field should be the environmental analysis of further process steps that include the presented unit processes and a subsequent statistical analysis in order to derive reliable data ranges for all unit processes. Such statistically robust ranges could be used in the approximation of missing life-cycle inventory data of other chemical products and intermediate

Quantifying cup overhang after total hip arthroplasty: standardized measurement using reformatted computed tomography and association of overhang distance with iliopsoas impingement

OBJECTIVES Currently, there is no standardized measurement method for evaluating cup overhang (CO) in patients undergoing total hip arthroplasty (THA). We propose a novel, standardized method of measuring overhang distance in patients following primary total hip arthroplasty (THA) on computed tomography (CT) images after multiplanar reformation and compare it to a previously proposed measurement method on sagittal CT images. MATERIALS AND METHODS This retrospective study included patients who underwent primary THA with an anterior approach. Patients with cup overhang (CO) and iliopsoas impingement (IPI) were identified by clinical and imaging data. Uncorrected overhang distance (OD$_{u}$) was evaluated on orthogonal sagittal CT images while corrected overhang distance (OD$_{c}$) was evaluated on reformatted sagittal CT images corrected for pelvic rotation and aligned with the plane of the cup face. RESULTS Out of 220 patients with THA, 23 patients (10.4%) with CO and 16 patients (7.3%) with IPI were identified. CO was significantly associated to IPI (p < 0.001). The inter- and intrareader agreement was almost perfect for OD$_{c}$ (κ = 0.822, κ = 0.850), whereas it was fair and moderate for OD$_{u}$ (κ = 0.391, κ = 0.455), respectively. The discriminative ability of OD$_{c}$ was excellent (area under the curve (AUC) = 0.909 (95% confidence interval (CI) 0.784-1.000)) in the receiver operating characteristic analysis. Conversely, AUC for OD$_{u}$ was poor, measuring 0.677 (95% CI 0.433-0.921). CONCLUSION We implemented a novel measurement method for CT images reformatted at the plane of the cup face to assess overhang distance in patients with CO following THA. CLINICAL RELEVANCE STATEMENT While further validation is necessary, the proposed method is characterized by its high reproducibility and might be used to predict the occurrence of iliopsoas impingement in patients with cup overhang following total hip arthroplasty. KEY POINTS • A novel, standardized method of measuring cup overhang distance in patients following primary total hip arthroplasty on CT images is proposed. • Cup overhang was associated to iliopsoas impingement. The proposed method was reproducible and showed excellent prediction of iliopsoas impingement in patients with cup overhang. • This method can be implemented in clinical practice when assessing CT images of patients with cup overhang for iliopsoas impingement

Bone marrow edema of the medioplantar talar head is associated with severe ligamentous injury in ankle sprain

PURPOSE To investigate the predictive value of talar head edema (THE) in acute ankle sprain for the presence of concomitant ligament injuries. METHODS This retrospective study was approved by the ethics committee and informed consent was obtained. One hundred patients (mean age: 37 years ± 14 [standard deviation], range 13-77 years) with MRI of the ankle after acute trauma were included. The cohort in this matched-pair study consisted of 50 patients with THE (group 1) and 50 patients without THE (group 2). Two readers independently evaluated presence and size of bone marrow edema of the talus head and injuries of the lateral, medial, talonavicular, and spring ligament complex. Statistics included intraclass correlation coefficient (ICC) and Kappa statistics as well as parametric and non-parametric tests. RESULTS On average, patients with THE demonstrated significantly more ligament injuries in comparison to patients without THE (3.7 vs. 1.3, p ≤ 0.01). Also, in patients with THE, the number of injured ligaments was significantly higher at the lateral (p = 0.03), medial (p ≤ 0.01), and talonavicular (p ≤ 0.01) compartment in comparison to patients without THE. The most frequently injured ligaments in patients with THE were the anterior talofibular ligament (60%) and the anterior tibiotalar ligament (42%). There was no significant correlation between edema size and the number of injured ligaments or compartments (p = 0.5). CONCLUSION THE is associated with more extensive ligamentous ankle injury, in particular to the medial and lateral collateral ligament complex, and therefore indicative of severe ankle trauma

Abductor tendon tears are associated with hypertrophy of the tensor fasciae latae muscle

Objective: To evaluate the association between hypertrophy of the tensor fasciae latae muscle and abductor tendon tears. Materials and methods: Thirty-five patients who underwent MRI of the abductor tendons of the hip were included in this retrospective study. A subgroup of 18 patients was examined bilaterally. The area of the tensor fasciae latae muscle and the area of the sartorius muscle (size reference) were quantified at the level of the femoral head, and a ratio was calculated. Two radiologists assessed the integrity of the gluteus medius and minimus tendon in consensus. Data were analyzed with a Mann-Whitney U test. Results: Sixteen out of 35 patients (46%) had a tear of the gluteus medius or minimus tendon. The ratio of the area of the tensor fasciae latae to the sartorius muscle was significantly higher (p = .028) in the group with an abductor tendon tear (median 2.25; Interquartile Range [IQR] = 1.97-3.21) compared to the group without any tears (median 1.91; IQR = 1.52-2.26). The bilateral subanalysis showed that in patients without a tear, the ratio of the two areas did not differ between each side (p = .966), with a median of 1.54 (primary side) and 1.76 (contralateral side). In patients with an abductor tendon tear the ratio was significantly higher (p = .031) on the side with a tear (median 2.81) compared to the contralateral healthy side (1.67). Conclusion: Patients with abductor tendon tears showed hypertrophy of the tensor fasciae latae muscle when compared to the contralateral healthy side and to patients without a tea

Ligaments of the Lisfranc joint in MRI: 3D-SPACE (sampling perfection with application optimized contrasts using different flip-angle evolution) sequence compared to three orthogonal proton-density fat-saturated (PD fs) sequences

Purpose: To compare the detection rate and visibility of the ligaments in the Lisfranc joint with a single 3D (−SPACE) MR sequence and three orthogonal PD fat-saturated sequences. Materials and methods: Thirty-one asymptomatic feet and 15 patients with posttraumatic pain in the Lisfranc joint were evaluated with a 3D-SPACE-sequence (0.5mm section thickness, acquisition time 10:22min, secondary reformations) and three orthogonal PD fs sequences (2mm section thickness, 9:20min). The Lisfranc-ligament, the dorsal and plantar tarsometatarsal ligaments (TMT), the dorsal, interosseous, and plantar intermetatarsal ligaments (IMT) (24 ligaments for each foot) were assessed. Results: In asymptomatic feet, 692 ligaments were detected with the SPACE sequence, thereof 90.6% exhibited normal signal, and most (96.9%) were completely visible on one single image. A total of 659 ligaments were detected with the PD fs sequence, thereof 86.6% yielded normal signal, and 28.5% were completely visible on one single image. In patients, 327 ligaments were detected with SPACE, thereof 50.6% appeared completely visible with high signal. On PD fs, 308 ligaments were detected, 42.2% of the ligaments had high signals. Conclusions: The ligaments of the Lisfranc joint are better detected with a single 3D-SPACE sequence and secondary reformations than with three orthogonal PD fs sequence

Relating remotely sensed forest damage data to wind data: storms Lothar (1999) and Vivian (1990) in Switzerland

This study compares the surface wind speed and forest damage data of two exceptionally severe winter storms, Vivian 1990 and Lothar 1999. The study area comprises the region that suffered damage in Switzerland. The wind speed data were derived from simulations of MeteoSwiss (Federal Office of Meteorology and Climatology), measurements during the storm periods and expert analyses of the data. The remotely sensed forest damage data were provided by the Federal Office for the Environment and the forest cover data by Swiss Federal Statistical Office. We compared data on the peak gust and maximum average wind speed, with data on the spatially related forest area and forest damage area, and found some clear differences in the correlations between the different wind data and forest damage. Our results point generally to the damage-causing role of near-surface gusts at maximum wind speeds during the storm. These tended to be spatially distributed on a fine scale. In only a few cases were the results statistically significant. However, these results could probably be improved with better wind data. For example, gust measurements spatially closer to forests or simulations of gusts at maximum wind speed could be produced with a spatially higher resolutio

The carpometacarpal joint of the thumb: MR appearance in asymptomatic volunteers

Purpose: To prospectively characterize the MR appearance of the carpometacarpal (CMC) joint of the thumb in asymptomatic volunteers. Materials and methods: Thirty-four asymptomatic volunteers (17 women, 17 men, mean age, 33.9 ± 9.2years) underwent MR imaging of the thumb after approval by the local ethical committee. Two musculoskeletal radiologists independently classified visibility and signal intensity (SI) characteristics of the anterior oblique (AOL/beak ligament), the posterior oblique (POL), the intermetacarpal (IML), and the dorsoradial ligaments (DRL) on a three-point Likert scale. The thickness of all ligaments, cartilage integrity, and presence of joint fluid were assessed. The alignment of the first metacarpal base with the trapezium was quantified on sagittal and coronal planes. Results: The ligaments of the CMC joint were constantly visible in all volunteers for the POL and IML, and in all but one for the AOL and DRL. On intermediate-weighted fat-saturated images the POL (65%/74% reader 1/reader 2) and DRL (58%/64%) were commonly of increased SI, while the IML had a striated appearance in 91%/76% of subjects. The AOL showed a variable SI (36%/42% low, 27%/27% increased, 36%/30% striated). The IML was the thickest ligament with a mean of 2.9mm/3.1mm and the DRL the thinnest (1.2mm/1.4mm). There was a mean dorsal subluxation of 1.8mm/2.0mm and radial subluxation of 2.8mm/3.4mm of the metacarpal base. The AOL was significantly thicker in men (1.7mm) than in women (1.2mm; p = 0.02). Radial subluxation was significantly larger in men (3.4mm) than in women (2.2mm; p = 0.02). No subluxation in palmar or ulnar direction was seen. Conclusions: Radial and dorsal subluxation of the CMC joint can be a normal finding in a resting position at MR imaging. The CMC ligaments showed a considerable variability of signal intensity with a typically striated IML; thickness of the AOL is typically less than 2.2mm, of the POL typically less than 2.9m

Factors associated with non-carbapenemase mediated carbapenem resistance of Gram-negative bacteria: a retrospective case-control study

Infections with carbapenemase-producing Gram-negative bacteria are related to increased morbidity and mortality, yet little is known regarding infections caused by non-beta-lactamase mediated carbapenem-resistant bacteria. Our objective was to identify risk factors for, and the clinical impact of infections caused by carbapenem-resistant carbapenemase-negative Enterobacterales and Pseudomonas aeruginosa. This retrospective matched case-control study was performed at the University Hospital of Basel, Switzerland, in 2016. We focused on other resistance mechanisms by excluding laboratory-confirmed carbapenemase-positive cases. Carbapenem resistance was set as the primary endpoint, and important risk factors were investigated by conditional logistic regression. The clinical impact of carbapenem resistance was estimated using regression models containing the resistance indicator as explanatory factor and adjusting for potential confounders. Seventy-five cases of infections with carbapenem-resistant, carbapenemase-negative bacteria were identified and matched with 75 controls with carbapenem-susceptible infections. The matched data set was well-balanced regarding age, gender, and comorbidity. Duration of prior carbapenem treatment (OR 1.15, [1.01, 1.31]) correlated with resistance to carbapenems. Our study showed that patients with carbapenem-resistant bacteria stayed 1.59 times (CI [0.81, 3.14]) longer in an ICU. The analyzed dataset did not provide evidence for strong clinical implications of resistance to carbapenems or increased mortality. The duration of prior carbapenem treatment seems to be a strong risk factor for the development of carbapenem resistance. The higher risk for a longer ICU stay could be a consequence of a carbapenem resistance. In contrast to carbapenemase-producers, the clinical impact of carbapenamase-negative, carbapenem-resistant strains may be limited. Trial registration: The study design was prospectively approved by the local Ethics Commission on 10.08.2017 (EKNZ BASEC 2017-00222)