Continuous Interscalene Brachial Plexus Blocks: An Anatomical Challenge between Scylla and Charybdis?

Brachial plexus blocks at the interscalene level are frequently chosen by physicians and recommended by textbooks for providing regional anesthesia and analgesia to patients scheduled for shoulder surgery. Published data concerning interscalene single-injection or continuous brachial plexus blocks report good analgesic effects. The principle of interscalene catheters is to extend analgesia beyond the duration of the local anesthetic's effect through continuous infusion, as opposed to a single injection. However, in addition to the recognized beneficial effects of interscalene blocks, whether administered as a single injection or through a catheter, there have been reports of consequences ranging from minor side effects to severe, life-threatening complications. Both can be simply explained by direct mispuncture, as well as undesired local anesthetic spread or misplaced catheters. In particular, catheters pose a high risk when advanced or placed uncontrollably, a fact confirmed by reports of fatal outcomes. Secondary catheter dislocations explain side effects or loss of effectiveness that may occur hours or days after the initial correct function has been observed. From an anatomical and physiological perspective, this appears logical: the catheter tip must be placed near the plexus in an anatomically tight and confined space. Thus, the catheter's position may be altered with the movement of the neck or shoulder, e.g., during physiotherapy. The safe use of interscalene catheters is therefore a balance between high analgesia quality and the control of side effects and complications, much like the passage between Scylla and Charybdis. We are convinced that the anatomical basis crucial for the brachial plexus block procedure at the interscalene level is not sufficiently depicted in the common regional anesthesia literature or textbooks. We would like to provide a comprehensive anatomical survey of the lateral neck, with special attention paid to the safe placement of interscalene catheters.

Image Correlation Between Digitally Reconstructed Radiographs, C-arm Fluoroscopic Radiographs, and X-ray: A Phantom Study.

OBJECTIVE: Digitally reconstructed radiographs (DRRs) are planar two-dimensional (2D) X-rays derived from a three-dimensional (3D) computed tomography (CT) dataset. DRRs allow the simulation of radiographs of all desired views and facilitate preoperative planning. However, orthopedic surgeons rely on C-arm fluoroscopic imaging during surgery to verify fracture reduction and implant placement. Pincushion distortion represents a technical limitation of fluoroscopic imaging, resulting in a greater distance between points at the periphery of the image compared to the center. This project, therefore, aimed to assess the image correlation between digitally reconstructed radiographs (DRRs) and fluoroscopic imaging (C-arm) using conventional radiographs (X-ray) as a control. METHODS: A 3D-printed cubic prototype and an anatomical humerus bone model were used. C-arm fluoroscopic radiographs and conventional X-ray images were taken in an anteroposterior (AP) view at 10-degree steps while rotating the objects from 0 to 90 degrees. CT scans were made and used to compute and export DRRs in AP view at 10-degree rotational steps from 0 to 90 degrees. The surface area (cm2) was measured and compared between the different modalities. For automated image analysis of the anatomical humerus model, matching (%) between modalities was calculated using the structural similarity index (SSIM). RESULTS: The overall regression was statistically significant in all models, with an R2 >0.99 when comparing all three imaging modalities of the prototype. Surface correlation in the anatomical humerus model was R2 0.99 between X-ray and C-arm and R2 0.95 between C-arm and X-ray to DRRs, respectively. The SSIM was highest for comparing DRR and C-arm images (0.84±0.01%). CONCLUSIONS: The study indicates a strong agreement between digitally reconstructed radiographs and X-ray/C-arm images. DRRs, therefore, represent a valuable tool for research and clinical application.

Anti-tumor effects of ketogenic diets and their synergism with other treatments in mice: Bayesian evidence synthesis of 1755 individual mouse survival data.

BACKGROUND: Ketogenic diets (KDs) are high-fat diets with putative anti-tumor effects. The aim of this study was to synthesize the evidence for the anti-tumor effects of KDs in mice, with a focus on their possible synergism with chemotherapy (CT), radiotherapy (RT), or targeted therapies (TT). METHODS: Relevant studies were retrieved from a literature search. A total of 43 articles reporting on 65 mouse experiments fulfilled the inclusion criteria, and 1755 individual mouse survival times were collated from the study authors or the publications. The restricted mean survival time ratio (RMSTR) between the KD and control groups served as the effect size. Bayesian evidence synthesis models were used to estimate pooled effect sizes and to assess the impact of putative confounders and synergism between KD and other therapies. RESULTS: Overall, there was a significant survival-prolonging effect of KD monotherapy (RMSTR = 1.161 ± 0.040), which was confirmed in meta-regression accounting for syngeneic versus xenogeneic models, early versus late KD start and subcutaneous versus other organ growth. Combining the KD with RT or TT, but not CT, was associated with a further 30% (RT) or 21% (TT) prolongation of survival. An analysis accounting for 15 individual tumor entities showed that KDs exerted significant survival-prolonging effects in pancreatic cancer (all treatment combinations), gliomas (KD + RT and KD + TT), head and neck cancer (KD + RT), and stomach cancer (KD+RT and KD + TT). CONCLUSIONS: This analytical study confirmed the overall anti-tumor effects of KDs in a large number of mouse experiments and provides evidence for synergistic effects with RT and TT.

Gadolinium-Based Contrast Agents and Free Gadolinium Inhibit Differentiation and Activity of Bone Cell Lineages.

OBJECTIVES: Administration of gadolinium-based contrast agents (GBCA) in magnetic resonance imaging results in the long-term retention of gadolinium (Gd) in tissues and organs, including the bone, and may affect their function and metabolism. This study aims to investigate the effects of Gd and GBCA on the proliferation/survival, differentiation, and function of bone cell lineages. MATERIALS AND METHODS: Primary murine osteoblasts (OB) and osteoclast progenitor cells (OPC) isolated from C57BL/6J mice were used to test the effects of Gd 3+ (12.5-100 µM) and GBCA (100-2000 µM). Cultures were supplemented with the nonionic linear Gd-DTPA-BMA (gadodiamide), ionic linear Gd-DTPA (gadopentetic acid), and macrocyclic Gd-DOTA (gadoteric acid). Cell viability and differentiation were analyzed on days 4-6 of the culture. To assess the resorptive activity of osteoclasts, the cells were grown in OPC cultures and were seeded onto layers of amorphous calcium phosphate with incorporated Gd. RESULTS: Gd 3+ did not affect OB viability, but differentiation was reduced dose-dependently up to 72.4% ± 6.2%-73.0% ± 13.2% (average ± SD) at 100 µM Gd 3+ on days 4-6 of culture as compared with unexposed controls ( P < 0.001). Exposure to GBCA had minor effects on OB viability with a dose-dependent reduction up to 23.3% ± 10.2% for Gd-DTPA-BMA at 2000 µM on day 5 ( P < 0.001). In contrast, all 3 GBCA caused a dose-dependent reduction of differentiation up to 88.3% ± 5.2% for Gd-DTPA-BMA, 49.8% ± 16.0% for Gd-DTPA, and 23.1% ± 8.7% for Gd-DOTA at 2000 µM on day 5 ( P < 0.001). In cultures of OPC, cell viability was not affected by Gd 3+ , whereas differentiation was decreased by 45.3% ± 9.8%-48.5% ± 15.8% at 100 µM Gd 3+ on days 4-6 ( P < 0.05). Exposure of OPC to GBCA resulted in a dose-dependent increase in cell viability of up to 34.1% ± 11.4% at 2000 µM on day 5 of culture ( P < 0.001). However, differentiation of OPC cultures was reduced on day 5 by 24.2% ± 9.4% for Gd-DTPA-BMA, 47.1% ± 14.0% for Gd-DTPA, and 38.2% ± 10.0% for Gd-DOTA ( P < 0.001). The dissolution of amorphous calcium phosphate by mature osteoclasts was reduced by 36.3% ± 5.3% upon incorporation of 4.3% Gd/Ca wt/wt ( P < 0.001). CONCLUSIONS: Gadolinium and GBCA inhibit differentiation and activity of bone cell lineages in vitro. Thus, Gd retention in bone tissue could potentially impair the physiological regulation of bone turnover on a cellular level, leading to pathological changes in bone metabolism.

Powder Bed Thermal Diffusivity Using Laser Flash Three Layer Analysis.

The thermal diffusivity of powder bed plays a crucial role in laser powder bed fusion (LPBF) additive manufacturing. The mechanical properties of the parts built by LPBF are immensely influenced by the thermal properties of the powder bed. This study aims to measure the thermal diffusivity of metallic powder, nickel-based super alloy Inconel718 (IN718), in LPBF using laser flash three-layered analysis in a DLF1600 instrument, which incorporates a special powder cell to encapsulate the powdered sample. Measurements were performed at different temperatures. The thermal diffusivity of several reference samples was measured for the purpose of validating the test results, and it was compared to published data for identical measures. It was observed that experimental results for powder samples were smaller than the actual thermal diffusivity of the sample. R software analysis was used to analyze test data in order to obtain powder thermal diffusivity values that were close to the actual values.

MRI findings of traumatic and degenerative rotator cuff tears and introduction of the "cobra sign".

Background: A rotator cuff tear (RCT) is a common shoulder diagnosis and its etiology may be acute, traumatic, or chronic degenerative. Differentiation between the 2 etiologies may be important for multiple reasons, but remains difficult based on imaging. Further knowledge about radiographic and magnetic resonance findings to distinguish traumatic from degenerative RCT is needed. Methods: We analyzed magnetic resonance arthrograms (MRAs) of 96 patients with traumatic or degenerative superior RCT, which were matched according their age and the affected rotator cuff muscle into the 2 groups. Patients older than 66 years of age were excluded from the study to avoid including cases with pre-existing degeneration. In the case of traumatic RCT, the time between the trauma and MRA had to be less than 3 months. Various parameters of the supraspinatus (SSP) muscle-tendon unit were assessed (tendon thickness, presence of a remaining tendon stump at the greater tubercle, magnitude of retraction, layer appearance). The retraction of the 2 SSP layers were individually measured to determine the difference of retraction. Additionally, edema of the tendon and muscle, the tangent- and kinking-sign as well as the newly introduced Cobra-sign (bulging of the distal part of the ruptured tendon with slim configuration of the medial part of the tendon) were analyzed. Results: Edema within the SSP muscle (sensitivity 13%, specificity 100%, P = .011) or the tendon (sensitivity 86%, specificity 36%, P = .014) are more frequent in traumatic RCT. The same association was found for the kinking-sign (sensitivity 53%, specificity 71%, P = .018) and the Cobra sign (sensitivity 47%, specificity 84%, P = .001). Even though not statistically significant, tendencies were observed toward thicker tendon stumps in traumatic RCT, and greater difference in retraction between the 2 SSP layers in the degenerative group. The cohorts had no difference in the presence of a tendon stump at the greater tuberosity. Conclusion: Muscle and tendon edema, as well as tendon kinking appearance and the newly introduced cobra-sign are suitable MRA parameters to distinguish between traumatic and degenerative etiology of a superior RTC.

[Ultrasound-guided low-volume continuous cervical sympathetic nerve block for treatment of an electrical storm]. / Ultraschallgestützte kontinuierliche zervikale Sympathikusblockade mit Niedrigvolumina zur Therapie bei anhaltender ventrikulärer Tachykardie.

In addition to the treatment for complex regional pain syndrome (CRPS), the stellate ganglion block is a treatment option for refractory intermittent ventricular tachycardia (VT). Despite the use of imaging techniques, such as fluoroscopy and ultrasound, numerous side effects and complications have been reported. These are a result of the complex anatomical site and the volume of injected local anesthetics. This article reports on the catheter placement for continuous block of the cervical sympathetic trunk with high-resolution ultrasound imaging (HRUI) in a patient with intermittent VT. The tip of the cannula was placed on the anterior aspect of the longus colli muscle and 20 mg prilocaine 1% (2 ml) was injected. The VT stopped and a continuous infusion of 1 ml/h ropivacaine 0,2 % was started. Nevertheless, during the next hour the patient developed hoarseness and dysphagia, so that a block of the recurrent laryngeal nerve and the deep ansa cervicalis (C1-C3) was carried out. The infusion was paused and restarted later with 0.5 ml/h. The spread of the local anesthetic was controlled by ultrasound. Over the next 4 days the patient showed no VT or detectable side effects. After implantation of a defibrillator 1 day later the patient could then be discharged home on the following day. This case shows that the HRUI can be advantageously used in the catheter placement and also when adjusting the flow rate. In this way the risk of complications and side effects related to the puncture and local anesthetic volume can be reduced.

Metabolic factors associated with the prognosis of oligometastatic patients treated with stereotactic body radiotherapy.

Over the past two decades, it has been established that cancer patients with oligometastases, i.e., only a few detectable metastases confined to one or a few organs, may benefit from an aggressive local treatment approach such as the application of high-precision stereotactic body radiotherapy (SBRT). Specifically, some studies have indicated that achieving long-term local tumor control of oligometastases is associated with prolonged overall survival. This motivates investigations into which factors may modify the dose-response relationship of SBRT by making metastases more or less radioresistant. One such factor relates to the uptake of the positron emission tomography tracer 2-deoxy-2-[18F]fluoro-D-glucose (FDG) which reflects the extent of tumor cell glycolysis or the Warburg effect, respectively. Here we review the biological mechanisms how the Warburg effect drives tumor cell radioresistance and metastasis and draw connections to clinical studies reporting associations between high FDG uptake and worse clinical outcomes after SBRT for oligometastases. We further review the evidence for distinct metabolic phenotypes of metastases preferentially seeding to specific organs and their possible translation into distinct radioresistance. Finally, evidence that obesity and hyperglycemia also affect outcomes after SBRT will be presented. While delivered dose is the main determinant of a high local tumor control probability, there might be clinical scenarios when metabolic targeting could make the difference between achieving local control or not, for example when doses have to be compromised in order to spare neighboring high-risk organs, or when tumors are expected to be highly therapy-resistant due to heavy pretreatment such as chemotherapy and/or radiotherapy.

Powder Spreading Mechanism in Laser Powder Bed Fusion Additive Manufacturing: Experiments and Computational Approach Using Discrete Element Method.

Laser powder bed fusion (LPBF) additive manufacturing (AM) has been adopted by various industries as a novel manufacturing technology. Powder spreading is a crucial part of the LPBF AM process that defines the quality of the fabricated objects. In this study, the impacts of various input parameters on the spread of powder density and particle distribution during the powder spreading process are investigated using the DEM (discrete element method) simulation tool. The DEM simulations extend over several powder layers and are used to analyze the powder particle packing density variation in different layers and at different points along the longitudinal spreading direction. Additionally, this research covers experimental measurements of the density of the powder packing and the powder particle size distribution on the construction plate.

Brooke-Spiegler syndrome: radiotherapy as the last resort?

PURPOSE: To describe the case of successful radiotherapeutic treatment of a woman suffering from Brooke-Spiegler syndrome who had multiple disfiguring cylindromas on the entire scalp and further tumors on the trunk. METHODS: After decades of treatment with conventional therapies including surgery and topically applied salicylic acid, the 73-year-old woman agreed to undergo radiotherapeutic treatment. She received 60 Gy to the scalp and 36 Gy to painful nodules in the lumbar spine region. RESULTS: Over a follow-up period of 14 and 11 years, respectively, the scalp nodules almost completely regressed, while the lumbar nodules became painless and considerably smaller. Apart from alopecia, no late adverse effects of treatment remain. CONCLUSION: This case should remind us of the potential role that radiotherapy could play in treating Brooke-Spiegler syndrome. The required dose for treatment of such extensive disease is still a matter of debate due to the scarcity of radiotherapeutic experience. This case demonstrates that for scalp tumors, 30â€¯× 2 Gy can result in long-term tumor control, while other dose prescriptions may be adequate for tumors in other locations.

Measurement of body composition by DXA, BIA, Leg-to-leg BIA and near-infrared spectroscopy in breast cancer patients - comparison of the four methods.

BACKGROUND & AIMS: Body composition plays a crucial role in therapy adherence and the prognosis of cancer patients. The aim of this work was to compare four measurement methods for determining body composition regarding their validity, reliability and practicability in order to be able to draft a practical recommendation as to which method is most suitable as a standard measurement method in oncology. METHODS: Fat mass (FM) and fat-free mass (FFM) was estimated for 100 breast cancer patients with ages of 18-70 years during a defined 20-week inpatient and outpatient rehabilitation process after primary therapy or follow-up rehabilitation. The four methods used were dual energy X-ray absorptiometry (DXA), bioelectrical impedance analysis (BIA), leg-to-leg BIA and near-infrared spectroscopy (NIRS). At baseline (t0) and after 20 weeks (t20) the agreement between the four body composition analysis methods was quantified by pairwise method comparisons using Bland-Altman bias and limits of agreement estimates, t-tests and Lin's concordance correlation coefficients (CCCs). RESULTS: CCCs and Bland-Altman plots indicated that DXA and BIA, DXA and NIRS as well as BIA and NIRS showed an excellent agreement concerning FM estimation at both time points (CCC>0.9). In contrast, no methods agreed with a CCC higher than 0.9 with respect to FFM estimation. However, most estimates were also significantly different between two methods, except for BIA and NIRS which yielded comparable FFM and FM estimates at both time points, albeit with large 95% limits of agreement intervals. The agreement between DXA and BIA was best in the lowest BMI tertile and worsened as BMI increased. Significant differences were also found for FFM changes measured with DXA versus BIA (mean difference -0.4 kg, p = 0.0049), DXA versus to Leg-to-leg BIA (-0.6 kg, p = 0.00073) and for FM changes measured with DXA versus Leg-to-leg BIA (0.5 kg, p = 0.0011). CONCLUSIONS: For accurate and valid body composition estimates, Leg-to-leg BIA cannot be recommended due to its significant underestimation of FM or significant overestimation of FFM, respectively. BIA and NIRS results showed good agreement with the gold standard DXA. Therefore both measurement methods appear to be very well suitable to assess body composition of oncological patients and should be used more frequently on a routine basis to monitor the body composition of breast cancer patients.

[Ultrasound-guided peripheral venepuncture under poor venous conditions]. / Ultraschallgesteuerte periphere Venenpunktion bei schlechtem Venenstatus.

Placement of a peripheral indwelling venous catheter is a routinely performed invasive procedure, in which complications are often underestimated. In difficult venous conditions multiple puncture attempts are often required, which are time consuming, unnecessarily painful for the patients and nevertheless not always successful. Due to the close anatomical relationship between superficial veins and peripheral nerves in the arm, puncture-related nerve injury is not uncommon. Despite limited data it could be shown that ultrasound-guided peripheral venepunctures are superior to traditional landmark techniques in terms of success rates, time saving, avoidance of complications and patient satisfaction. In order to successfully integrate the sonographic puncture technique for vascular access into routine processes, a structured training and further education are prerequisites. This must include anatomical knowledge, basic knowledge of ultrasound formation and training in sonographic needle guidance techniques.

SEIR models in the light of Critical Realism - A critique of exaggerated claims about the effectiveness of Covid 19 vaccinations.

In a recent modeling study Watson et al. (Lancet Infect Dis 2022;3099:1-10) claim that Covid-19 vaccinations have helped to prevent roughly 14-20 million deaths in 2021. This conclusion is based on an epidemiological susceptible-exposed-infectious-recovered (SEIR) model trained on partially simulated data and yielding a reproduction number distribution which was then applied to a counterfactual scenario in which the efficacy of vaccinations was removed. Drawing on the meta-theory of Critical Realism, we point out several caveats of this model and caution against believing in its predictions. We argue that the absence of vaccinations would have significantly changed the causal tendencies of the system being modelled, yielding a different reproduction number than obtained from training the model on actually observed data. Furthermore, the model omits many important causal factors. Therefore this model, similar to many previous SEIR models, has oversimplified the complex interplay between biomedical, social and cultural dimensions of health and should not be used to guide public health policy. In order to predict the future in epidemic situations more accurately, continuously optimized dynamic causal models which can include the not directly tangible, yet real causal mechanisms affecting public health appear to be a promising alternative to SEIR-type models.

Standardized multi-planar reformation improves the reliability of the assessment of the anterolateral ligament in ACL-deficient knees.

PURPOSE: The anterolateral ligament (ALL) is an important structure for controlling anterolateral rotatory stability of the knee. Its assessment, however, is difficult using standardized MRI images. The goal of this study was to assess the reliability of judging the integrity of the ALL on multi-planar reformatted (MPR) MRI images and on standard coronal reformatted (SCR) MRI images in knees with an anterior cruciate ligament (ACL) rupture. METHODS: Forty-eight patients (14 females, 34 males, 30 ± 6 years (mean age ± standard deviation)) with acute ACL ruptures (< 2 weeks) and no additional knee injuries (except segond fractures) were included. Images were assessed by two independent raters twice with at least a 2-week interval in between. The assessment was first performed on SCR images and thereafter on MPR images. Images were judged for assessability of the ALL and then the integrity of the ALL was rated. RESULTS: Depending on rater and read, the ALL was judged as "torn" in between 5 (10.4%) and 11 (22.9%) patients out of 48 patients on SCR images. On MRP images, the ALL was judged as "torn" in between 5 (10.4%) and 6 (12.5%) patients out of 48 patients, depending on rater and read. Inter- and intra-rater reliability for the assessment of the ALL using MPR images was "substantial" to "almost perfect". Inter- and intra-rater reliability for the assessment using SCR was "fair" to "substantial". CONCLUSION: MPR images should be used when assessing the integrity of the ALL. Assessment quality is independent of patient positioning during MRI acquisition and the ALL can be displayed in full length on one image. LEVEL OF EVIDENCE: Level III.

Effect of Ketogenic Diets on Cardio-Metabolic Outcomes in Cancer Patients: A Systematic Review and Meta-Analysis of Controlled Clinical Trials.

In this systematic review and meta-analysis of clinical controlled trials (CCTs) we aimed to investigate the efficacy of KDs as an adjuvant therapy on cardiometabolic outcomes in patient with cancer compared to conventional non-ketogenic diets. Only CCTs involving cancer patients that were assigned to either a KD or a standard diet control group were selected. Two reviewers independently extracted the data, and a meta-analysis was performed using a random effects model to estimate weighted mean differences (WMDs) and confidence intervals (CIs) in body composition, metabolite, lipid profile, liver and kidney function parameters and quality of life. This meta-analysis showed a significant reduction in body weight (WMD= -2.99 kg; 95% CI: -4.67, -1.31; and P < 0.001), BMI (WMD= -1.08 kg/m2; 95% CI: -1.81, -0.34; P ≤ 0.002) and fat mass (WMD= -1.48 kg; 95% CI: -2.56, -0.40; and P = 0.007) by a KD. KDs significantly decreased glucose (WMD= -5.22 mg/dl; 95% CI: -9.0, -1.44; and P = 0.007), IGF-1 (WMD= -17.52 ng/ml; 95% CI: -20.24, -14.8; and P ˂0.001) and triglyceride (WMD= -24.46 mg/dl; 95% CI: -43.96, -4.95; and P = 0.014) levels. Furthermore, KDs induced ketosis by increasing ß-hydroxybutyrate (WMD= 0.56 mmol/l; 95% CI: 0.37, 0.75; and P < 0.001). There were non-significant pooled effects of KDs on improving insulin, C-reactive protein and cholesterol levels and kidney and liver function. Emotional functioning was even increased significantly in the KD compared to the SD groups. In summary we found that KDs result in a greater reduction in glucose, IGF-1, triglycerides, body weight, BMI, and fat mass in cancer patients compared to traditional non-ketogenic diets and improved emotional functioning. The quality of evidence in the meta-analysis was moderate according to the Nutrigrade assessment.

The robustness of glenohumeral centering measurements in dependence of shoulder rotation and their predictive value in shoulders with rotator cuff tears.

OBJECTIVE: De-centering of the shoulder joint on radiographs is used as indicator for severity of rotator cuff tears and as predictor for clinical outcome after surgery. The objective of the study was to assess the effect of malrotation on glenohumeral centering on radiographs and to identify the most reliable parameter for its quantification. SUBJECTS AND METHODS: In this retrospective study (2014-2018), 249 shoulders were included: 92 with imaging-confirmed supra- and infraspinatus tears (rupture; 65.2 ± 9.9 years) and 157 without tears (control; 41.1 ± 13.0 years). On radiographs in neutral position and external rotation, we assessed three radiographic parameters to quantify glenohumeral centering: acromiohumeral distance (ACHD), craniocaudal distance of the humeral head and glenoid center (Deutsch), and scapulohumeral arch congruity (Moloney). Non-parametric statistics was performed. RESULTS: In both positions, only the distance parameters ACHD (< 0.5 mm) and Deutsch (< 1 mm) were comparable in the two study groups rupture and control. Comparing the parameters between the study groups revealed only ACHD to be significantly different with a reduction of more than 2 mm in the rupture group. Among the parameters, ACHD ≤ 6 mm was the only cut-off discriminating rupture (12-21% of the shoulders with ACHD ≤ 6 mm) and control (none of the shoulders with ACHD ≤ 6 mm). Ninety percent of shoulders with ACHD ≤ 6 mm presented with a massive rotator cuff tear (defined as ≥ 67% of the greater tuberosity exposed). CONCLUSION: Glenohumeral centering assessed by ACHD and Deutsch is not affected by rotation in shoulders with and without rotator cuff tear. An ACHD ≤ 6 mm has a positive predictive value of 90% for a massive rotator cuff tear.

The relationship between the lateral cutaneous antebrachial nerve and the superficial branch of the radial nerve and its impact on regional anesthetic and pain blocks of the thumb; What is more important: Nerves or dermatomes?

BACKGROUND: Innervation of the thumb and radial part of the dorsum of the hand is achieved primarily by the radial nerve, which is usually blocked for hand surgery. Inefficient blocks occur because the lateral antebrachial cutaneous nerve also extends into this area. The question then arises, whether skin innervation and peripheral blocking techniques should be directed at from the innervation by these nerves or more by the dermatome and its spinal segments. METHODS: In 68 human upper limbs embalmed with Thiel's method, the topography of the lateral antebrachial cutaneous nerve (LACN), the superficial branch of the radial nerve (sbRN) and communicating branch (CB) were investigated by meticulous dissection from the cubital fossa to the most distal macroscopically dissectible branch, and the areas reached by these nerves were compared to the described dermatome. RESULTS: In 52.9% of all specimens, the LACN was found proximal to the rascetta, in 35.3% it extended to the base of the thumb, and in 8 cases (11.8%) it extended distally to the base of the thumb. In 50%, the LACN was anterolateral to the brachioradialis muscle, and in 38.2%, strictly lateral. Only in 8 cases (11.8%) the LACN presented itself running more dorsally and laterally. A CB was observed in 28 specimens (41.2%). Both investigated nerves were found to innervate the dermatomes of C6 and C7. CONCLUSIONS: The LACN should be considered for individual targeted blocks for surgical procedures and pain therapy within the wrist and thumb region as all nerves that might contribute to innervation of a targeted dermatome should be blocked.

Broadband infrared confocal imaging for applications in additive manufacturing.

We address new measurement challenges relating to 3D printing in metal powder using the powder bed fusion technique. Using a combination of confocal microscopy principles and fast, sensitive mid-infrared collection techniques, we present a compact and versatile method of measuring and analyzing broadband thermal emissions from the vicinity of the molten metal pool during the additive manufacturing process. We demonstrate the benefits of this instrumentation and potential for scientific research as well as in situ monitoring. Our compact microscope collection optics can be implemented in various powder bed fusion machines under vacuum or inert atmospheric environments to enable extensions such as multi-color pyrometry or spectroscopic studies of additive manufacturing processes.

Is the Network of World Economic Forum Young Global Leaders Associated With COVID-19 Non-Pharmaceutical Intervention Severity?

Background TheWorld Economic Forum (WEF) has spawned a global network of elites called Young Global Leaders (YGLs) with significant influence on large corporations, politics, academia, and media. This article scrutinizes the idea that through this network, the WEF had a significant influence on the scale and scope of the non-pharmaceutical interventions (NPIs) implemented in response to the COVID-19 crisis. We tested for associations between the country-level distribution of YGLs and the intensity and duration of the implemented NPIs summarized by the Government Response Severity Index (GRSI). Materials and methods The number and category of YGLs per country was extracted from the WEF website. We also extracted the maximum and median GRSI values for three time periods: (i) the beginning of the first wave of the pandemic (March 1, 2020, to April 30, 2020), (ii) the height of the second wave in Europe (December 1, 2020, to January 31, 2021), and (iii) the approximate first year (March 1, 2020, to January 31, 2021). Being a precondition for causality, any association between the total or category-specific number of YGLs and the GRSI values in each time period was evaluated using Spearman's ρ correlation coefficients and polynomial regression, respectively. Results There was a highly significant positive correlation between the total number of YGLs in a country and the median (ρ = 0.36, p = 2.5×10-7) and maximum (ρ = 0.34, p = 1.6×10-6) GRSI during the second wave of the pandemic, but not during the first wave. The total number of YGLs was also a significant predictor of higher median GRSI during the second wave of the pandemic in the best-fitting (four-degree) polynomial regression model (p<0.01); additional significant and positive predictor in this model was a country's location within Europe or South America, respectively (p<0.01). Investigating an influence-weighted number of YGLs in business, politics, and civic society separately yielded no significant associations with NPI severity for any of the three time periods. Conclusions As there were significant correlations during the second, but not the first wave of the pandemic, we conclude that the WEF might not have been the origin of but rather an echo-chamber or amplifier for certain opinions and strategies that were formed and implemented during or before the first months of the COVID-19 crisis. Future qualitative studies may reveal putative causal mechanisms underlying our observed correlations.

Treatment of Knee Dislocation With Primary Repair and Suture Augmentation: A Viable Solution.

Background: Different surgical techniques have been described for the treatment of knee dislocation (KD). Nonoperative approaches are frequently combined with surgical reconstruction using auto- or allograft. Purpose: To evaluate the midterm results of primary surgical repair and suture augmentation to treat KD. Study Design: Case series; Level of evidence, 4. Methods: A total of 22 patients (5 women, 17 men; mean age, 45 ± 15 years) with KD were evaluated at a mean of 49 ± 16 months after surgical treatment that included primary repair and suture augmentation. Magnetic resonance imaging, stress radiographs, and outcome scores were obtained at the follow-up. Clinical examination including hop tests and force measurements for flexion and extension was performed. Results: The mean difference in pre- to postinjury Tegner scores was -2 ± 1. The outcome scores showed mean values of 84 ± 15 (Lysholm), 73 ± 15 (International Knee Documentation Committee) and 65 ± 25 (Anterior Cruciate Ligament-Return to Sport after Injury scale). Compared with the uninjured knee, the range of motion of the injured knee was reduced by 21° ± 12°. Twelve patients felt fit enough to perform hop tests and showed a mean deficit of 7% ± 17%° compared with the uninjured leg. The mean force deficit was 19% ± 18% for extension and 8% ± 16% for flexion. Stress radiographs revealed an 11 ± 7-mm higher anteroposterior translation on the injured side. Four patients had secondary ligament reconstructions due to persistent instability and 7 underwent arthroscopic arthrolysis due to stiffness. A significant increase of osteoarthritis was found for the medial, lateral, and patellofemoral compartments (P = .007, .004, and .006, respectively). Conclusion: Primary repair and suture augmentation of KD led to satisfactory clinical midterm results despite persistent radiological instability and a significant increase in osteoarthritis. This technique allows the return to activities of daily living without subjective instability in most nonathletic patients. Secondary ligament reconstructions should be performed if relevant instability persists to decrease the risk of secondary meniscal and cartilage damage.