Geometric Cuts by an Autonomous Laser Osteotome Increase Stability in Mandibular Reconstruction With Free Fibula Grafts: A Cadaver Study.

BACKGROUND: Nonunion and plate exposure represent a major complication after mandibular reconstruction with free fibula flaps. These drawbacks may be resolved by geometric osteotomies increasing intersegmental bone contact area and stability. PURPOSE: The aim of this study was to compare intersegmental bone contact and stability of geometric osteotomies to straight osteotomies in mandibular reconstructions with free fibula grafts performed by robot-guided erbium-doped yttrium aluminum garnet laser osteotomy. STUDY DESIGN, SETTING, SAMPLE: This cadaveric in-vitro study was performed on fresh frozen human skull and fibula specimens. Computed tomography (CT) scans of all specimens were performed for virtual planning of mandibular resections and three-segment fibula reconstructions. The virtual planning was implemented in a Cold Ablation Robot-guided Laser Osteotome. PREDICTOR/EXPOSURE/INDEPENDENT VARIABLE: For predictor variables, straight and geometric puzzle-shaped osteotomies were designed at resection of the mandible and corresponding fibula reconstruction. MAIN OUTCOME VARIABLES: The primary outcome variable was the stability of the reconstructed mandible investigated by shearing tests. Moreover, secondary outcome variables were the duration of the laser osteotomies, the contact surface area, and the accuracy of the reconstruction, both evaluated on postsurgical CT scans. COVARIATES: Covariables were not applicable. ANALYSES: Data were reported as mean values (± standard deviation) and were statistically analyzed using an independent-sample t-test at a significance level of α = 0.05. Root mean square deviation was tested for accuracy. RESULTS: Eight skulls and 16 fibula specimens were used for the study. One hundred twelve successful laser osteotomies (96 straight and 16 geometrical) could be performed. Geometric osteotomies increased stability (110.2 ± 36.2 N vs 37.9 ± 20.1 N, P < .001) compared to straight osteotomies. Geometric osteotomy of the fibula took longer than straight osteotomies (10.9 ± 5.1 min vs 5.9 ± 2.2 min, P = .028) but could provide larger contact surface (431.2 ± 148.5 mm2 vs 226.1 ± 50.8 mm2, P = .04). Heat map analysis revealed a mean deviation between preoperational planning and postreconstructive CT scan of -0.8 ± 2.4 mm and a root mean square deviation of 2.51 mm. CONCLUSION AND RELEVANCE: Mandibular resection and reconstruction by fibula grafts can be accurately performed by a Cold Ablation Robot-guided Laser Osteotome without need for cutting guides. Osteotomy planning with geometric cuts offers higher stability and an increased bone contact area, which may enhance healing of the reconstructed mandible.

Is restoration of vertebral body height after vertebral body fractures and minimally-invasive dorsal stabilization with polyaxial pedicle screws just an illusion?

INTRODUCTION: Thoracolumbar spine fractures often require surgical treatment as they are associated with spinal instability. Optimal operative techniques and treatment are discussed controversially. Aim of our prospective cohort study was to investigate the sagittal alignment after reduction, the secondary loss of reduction and the subjective outcome as well as the causal correlation of these parameters after minimally invasive stabilization of thoracic and lumbar fractures with polyaxial pedicle screws. MATERIALS AND METHODS: In a single-center study, a total of 78 patients with an average age of 61 ± 17 years who suffered a fracture of the thoracic or lumbar spine were included and subjected to a clinical and radiological follow-up examination after 8.5 ± 8 months. The kyphotic deformity was measured by determining the vertebral body angle, the mono- and bi-segmental wedge angle at three time points. The patients' subjective outcome was evaluated by the VAS spine score. RESULTS: After surgical therapy, a significant reduction of the traumatic kyphotic deformity was shown with an improvement of all angles (vertebral body angle: 3.2° ± 4.4°, mono- and bi-segmental wedge angle: 3.1° ± 5.6°, 2.0° ± 6.3°). After follow-up, a significant loss of sagittal alignment was observed for all measured parameters with a loss of correction. However, no correlation between the loss of reduction and the subjective outcome regarding the VAS spine scale could be detected. CONCLUSION: The minimally invasive dorsal stabilization of thoracic and lumbar spine fractures with polyaxial pedicle screws achieved a satisfactory reduction of the fracture-induced kyphotic deformity immediately postoperatively with a floss of reduction in the further course. However, maybe the main goal of this surgical procedure should be the prevention of a complete collapse of the vertebral body instead of a long-lasting restoration of anatomic sagittal alignment. LEVEL OF EVIDENCE: II.

Characterization of a cotton-wool like composite bone graft material.

Bone graft materials are applied in patients to augment bone defects and enable the insertion of an implant in its ideal position. However, the currently available augmentation materials do not meet the requirements of being completely resorbed and replaced by new bone within 3 to 6 months. A novel electrospun cotton-wool like material (Bonewool®, Zurich Biomaterials LLC, Zurich, Switzerland) consisting of biodegradable poly(lactic-co-glycolic) acid (PLGA) fibers with incorporated amorphous ß-tricalcium phosphate (ß-TCP) nanoparticles has been compared to a frequently used bovine derived hydroxyapatite (Bio-Oss®, Geistlich Pharma, Wolhusen, Switzerland) in vitro. The material composition was determined and the degradation behavior (calcium release and pH in different solutions) as well as bioactivity has been measured. Degradation behavior of PLGA/ß-TCP was generally more progressive than for Bio-Oss®, indicating that this material is potentially completely resorbable. Graphical abstract.

Single and double bundle posterior cruciate ligament reconstruction yield comparable clinical and functional outcomes: a systematic review and meta-analysis.

PURPOSE: To perform a systematic review and compare the functional and objective outcomes after single-bundle (SB) vs. double-bundle (DB) posterior cruciate ligament reconstruction (PCLR). Where possible to pool outcomes and arrive at summary estimates of treatment effect for DB PCLR vs. SB PCLR via an embedded meta-analysis. METHODS: A comprehensive PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) literature search identified 13 eligible studies evaluating clinical outcomes of both techniques for PCLR. Clinical outcome measures included in the meta-analysis were functional outcomes (Lysholm Score, Tegner Activity Scale) and objective measurements of posterior laxity of the operated knee (arthrometer and stress radiographs). RESULTS: The meta-analysis included 603 patients. Three hundred and fifteen patients were treated with SB and two hundred and eighty-eight patients with DB PCLR. There were no significant differences between SB and DB PCLR in postoperative functional Lysholm Scores (CI [- 0.18, 0.17]), Tegner Activity Scales (CI [- 0.32, 0.12]) and IKDC objective grades (CI [- 0.13, 1.17]). Regarding posterior stability using KT-1000 and Kneelax III arthrometer measurements, there were no differences between the SB and DB group. However, double-bundle reconstruction provided better objective outcome of measurement of posterior laxity (CI [0.02, 0.46]) when measured with Telos stress radiography. CONCLUSION: A systematic review was conducted to identify current best evidence pertaining to DB and SB PCLR. An embedded meta-analysis arrived at similar summary estimates of treatment effect for motion, stability and overall function for both techniques. There is no demonstrable clinically relevant difference between techniques based on the currently available evidence. LEVEL OF EVIDENCE: III.

The Effect of Breast Size on Spinal Posture.

Macromastia can cause various clinical symptoms, such as low back and shoulder pain as well as sacro-iliac disorders. Because of these symptoms, some women consider breast reduction surgery. So far there does not exist a clear correlation between breast size and back pain. Purpose of this study was to evaluate if increasing breast size has a measurable effect on women's posture using radiation free surface topography.A total of 100 women were grouped according to their breast cup size into four groups (Cup Size: A, B, C, D). All female subjects were measured with a surface topography system, and their spinal posture and pelvic position were analysed accordingly.Our results showed that cup size affects kyphotic angle (p = 0.027) and surface rotation (p = 0.039) significantly. Kyphotic angle increased with cup size. Multiple linear regression analysis, however, revealed that the body mass index has the greatest influence on woman's posture, showing significant correlation to kyphotic and lordotic angle (p < 0.01), as to trunk (p < 0.01) and pelvic inclination (p = 0.02).This is the first study that evaluates the influence of increasing breast size on posture using surface topography. The results match with previous studies using different measuring techniques. However, the great influence of BMI on posture is also confirmed. Therefore, in clinical practice these factors should be taken into account and be approached. Surface topography seems to be a promising tool to further investigate the influence of breast size on posture.Level of Evidence IV This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Paradata analyses to inform population-based survey capture of pregnancy outcomes: EN-INDEPTH study.

BACKGROUND: Paradata are (timestamped) records tracking the process of (electronic) data collection. We analysed paradata from a large household survey of questions capturing pregnancy outcomes to assess performance (timing and correction processes). We examined how paradata can be used to inform and improve questionnaire design and survey implementation in nationally representative household surveys, the major source for maternal and newborn health data worldwide. METHODS: The EN-INDEPTH cross-sectional population-based survey of women of reproductive age in five Health and Demographic Surveillance System sites (in Bangladesh, Guinea-Bissau, Ethiopia, Ghana, and Uganda) randomly compared two modules to capture pregnancy outcomes: full pregnancy history (FPH) and the standard DHS-7 full birth history (FBH+). We used paradata related to answers recorded on tablets using the Survey Solutions platform. We evaluated the difference in paradata entries between the two reproductive modules and assessed which question characteristics (type, nature, structure) affect answer correction rates, using regression analyses. We also proposed and tested a new classification of answer correction types. RESULTS: We analysed 3.6 million timestamped entries from 65,768 interviews. 83.7% of all interviews had at least one corrected answer to a question. Of 3.3 million analysed questions, 7.5% had at least one correction. Among corrected questions, the median number of corrections was one, regardless of question characteristics. We classified answer corrections into eight types (no correction, impulsive, flat (simple), zigzag, flat zigzag, missing after correction, missing after flat (zigzag) correction, missing/incomplete). 84.6% of all corrections were judged not to be problematic with a flat (simple) mistake correction. Question characteristics were important predictors of probability to make answer corrections, even after adjusting for respondent's characteristics and location, with interviewer clustering accounted as a fixed effect. Answer correction patterns and types were similar between FPH and FBH+, as well as the overall response duration. Avoiding corrections has the potential to reduce interview duration and reproductive module completion by 0.4 min. CONCLUSIONS: The use of questionnaire paradata has the potential to improve measurement and the resultant quality of electronic data. Identifying sections or specific questions with multiple corrections sheds light on typically hidden challenges in the survey's content, process, and administration, allowing for earlier real-time intervention (e.g.,, questionnaire content revision or additional staff training). Given the size and complexity of paradata, additional time, data management, and programming skills are required to realise its potential.

Meta-analysis of the validity and reliability of rasterstereographic measurements of spinal posture.

OBJECTIVE: We provide a meta-analysis for clinicians and researchers regarding reliability and validity of rasterstereographic measurement of the spinal posture. METHOD: A comprehensive PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) literature search identified 19 eligible studies evaluating reliability and validity of static rasterstereographic measurements in healthy subjects and patients with different spinal pathologies. RESULTS: Our meta-analysis suggests that rasterstereography is a reliable and valid instrument to assess spinal posture parameters, especially thoracic kyphosis, lumbar lordosis, and scoliosis, reliability overall effect sizes rs > .91, ps < .001, validity overall effect sizes rs > 70, ps < .001, when compared to traditional radiological imaging techniques. Validity is higher in scoliosis patients compared with healthy controls. Limitations are a lack of reported statistics of the included studies and small sample sizes. CONCLUSION: The first meta-analysis on reliability and validity of rasterstereography shows satisfactory results. Rasterstereography thus presents a reliable and valid alternative to classic radiological imaging technique to assess and evaluate spinal posture in patients with spinal pathologies. Further studies are needed, focusing on the measurement properties of both static and dynamic rasterstereographic measurements.

Three anchor concepts for rotator cuff repair in standardized physiological and osteoporotic bone: a biomechanical study.

BACKGROUND: Previous biomechanical studies used single-pull destructive tests in line with the anchor and are limited by a great variability of bone density of cadaver samples. To overcome these limitations, a more physiological test setting was provided using titanium, bioresorbable, and all-suture anchors. METHODS: In this controlled laboratory study, 3 anchor constructs were divided into 2 groups: physiological and osteoporotic. Sixty standardized artificial bone specimens (=10 for each anchor in each group) were used for biomechanical testing. The anchors were inserted at a 45° angle as during surgery. Cyclic loading for 1000 cycles followed by ultimate load-to-failure (ULTF) testing was performed. Elongation, ultimate load at failure, and the mode of failure were noted. RESULTS: In the physiological group, the ULTF for the all-suture anchor (mean [standard deviation], 632.9 [96.8 N]) was found to be significantly higher than for the other anchors (titanium, 497.1 [50.5] N, and bioresorbable, 322.4 [3.1 N], P < .0001). The titanium anchor showed a significantly higher ULTF than the bioresorbable anchor (P < .0001). In the osteoporotic group, the all-suture anchor again showed a higher ULTF compared to the bioresorbable anchor (500.9 [50.6] N vs. 315.1 [11.3] N, P < .0001). In the osteoporotic group, cyclic loading revealed a higher elongation after 1000 loading cycles for the bioresorbable (0.40 [0.12] mm) compared to the titanium (0.22 [0.11] mm; P = .01) as well as the all-suture anchor (0.19 [0.15] mm, P = .003). CONCLUSION: Regarding ULTF, the all-suture anchor outperformed the other anchors in physiological bone, but in osteoporotic bone, significance was reached only compared to the bioresorbable anchor. Although cyclic loading revealed significant differences, these might not be clinically relevant.

The new LassoLoop360° technique for biomechanically superior tissue grip.

PURPOSE: Suprapectoral tenodesis is a frequently used technique for treating pathologies of the long head of the biceps brachii (LHBB) tendon. However, so far, no Gold Standard treatment exist. Hence, the arthroscopic LassoLoop360 (LL360) technique is introduced aiming to provide secure fixation and improved biomechanical properties. It was hypothesized, that the LL360 technique would show superior biomechanical response to cyclic loading and ultimate load-to-failure testing compared to the commonly used simple Lasso Loop (SLL). METHODS: Twenty-two porcine superficial flexor digitorum tendons were prepared using a No. 2 suture according to either the SLL or the LL360 technique. Displacement after cyclic loading (1.000 cycles) between 5 and 30 N, ultimate load-to-failure (ULTF), mode of failure as well as the construct stiffness were tested. RESULTS: Significantly less displacement was found in the LL360 group (SLL 2.25 ± 0.51 mm; LL360 1.67 ± 0.37 mm; p = 0.01). Ultimate Load to Failure was significantly higher in the LL360 (168.6 ± 29.6 N) as compared to the SLL (124.1 ± 25.8 N, p = 0.02). The LL360 also revealed a significant higher stiffness compared to the SLL (SLL 13.1 ± 0.9 N/mm vs. LL360 19.1 ± 1.0 N/mm, p < 0.001). The most common mode of failure was the suture cutting through the tendon, with a significantly less suture cutting through for the LL360 compared with the SLL (p < 0.05). CONCLUSION: The LassoLoop360-technique offers superior biomechanical characteristics regarding the tendon-suture-interface compared to the SLL. In the initial healing phase, the suture-tendon-interface is the most vulnerable part of the tendon-suture-anchor construct, the aim of this new technique is to reduce this weakest part of the chain (Ponce et al., Am J Sports Med 39:188-194, 2011). This technique may therefore be beneficial for arthroscopic suprapectoral biceps tenodesis at the entrance of the bicipital groove.

A new model of implant-related osteomyelitis in the metaphysis of rat tibiae.

BACKGROUND: Animal models serve as an important tool to understand peri-implant infection. Most of the models use high bacterial loads (>10(4) colony forming units, CFU) to provide high infection rates. Therefore these animals evolve rather similarly, making comparison between groups and statistical analysis possible. On the other hand, to mimic clinical constellation of surgery-related infections the use of low amounts of bacteria would be more advantageous. METHODS: We developed a metaphyseal rat model of peri-implant bone infection with low amount of bacterial loads (10(2) and 10(3) CFU of Staphylococcus aureus) and investigated osseointegration of the implants coated with hydroxyapatite (HA) and low-dosed HA-silver (HA-Ag). Non-infected implants served as controls. After 6 weeks rats were sacrificed and implants evaluated for osseointegration and infection. RESULTS: Infection of implanted devices was reliably induced, independently whether 10(2) or 10(3) CFU of S. aureus were inoculated and HA or HA-Ag coated implants were used. No systemic infection was present in any of the animals at the time of sacrifice, and no animal developed acute infection requiring premature sacrifice. All CFU counts of the implant and the bone at sacrifice were significantly higher than the inoculated load (p < .05). All sterilely inserted implants showed excellent osseointegration and no infection. CONCLUSIONS: Our present study of a rat tibia model reliably induced osteomyelitis in the metaphysis with low-doses of bacteria. The addition of low-dosed Ag to the implant coating was not able to reduce the infection rates. The results demonstrate that it is possible to develop a model of implant-related osteomyelitis in rats with low amounts of bacteria to better mimic clinical constellations. No other promoters of infection besides insertion of the screw implant were used in this model.

The Arabidopsis DELLA RGA-LIKE3 is a direct target of MYC2 and modulates jasmonate signaling responses.

Gibberellins (GAs) are plant hormones involved in the regulation of plant growth in response to endogenous and environmental signals. GA promotes growth by stimulating the degradation of nuclear growth-repressing DELLA proteins. In Arabidopsis thaliana, DELLAs consist of a small family of five proteins that display distinct but also overlapping functions in repressing GA responses. This study reveals that DELLA RGA-LIKE3 (RGL3) protein is essential to fully enhance the jasmonate (JA)-mediated responses. We show that JA rapidly induces RGL3 expression in a CORONATINE INSENSITIVE1 (COI1)- and JASMONATE INSENSITIVE1 (JIN1/MYC2)-dependent manner. In addition, we demonstrate that MYC2 binds directly to RGL3 promoter. Furthermore, we show that RGL3 (like the other DELLAs) interacts with JA ZIM-domain (JAZ) proteins, key repressors of JA signaling. These findings suggest that JA/MYC2-dependent accumulation of RGL3 represses JAZ activity, which in turn enhances the expression of JA-responsive genes. Accordingly, we show that induction of primary JA-responsive genes is reduced in the rgl3-5 mutant and enhanced in transgenic lines overexpressing RGL3. Hence, RGL3 positively regulates JA-mediated resistance to the necrotroph Botrytis cinerea and susceptibility to the hemibiotroph Pseudomonas syringae. We propose that JA-mediated induction of RGL3 expression is of adaptive significance and might represent a recent functional diversification of the DELLAs.

Spinal posture and pelvic position during pregnancy: a prospective rasterstereographic pilot study.

PURPOSE: Despite the high prevalence of low back pain during pregnancy there is still a lack in the understanding of its aetiology. Changes of the spinal posture due to the anatomical changes of the pregnant body seem to be in part responsible for the back pain. In this pilot study we assessed the potential to accurately measure the spinal posture and pelvic position during pregnancy without any harmful radiation using a spine and surface topography system. METHODS: Thirteen pregnant women were examined during the second and third trimester of their pregnancy, and postpartum. Twenty female, non-pregnant volunteers comprised the control group. The spinal posture and pelvic position were measured with a radiation-free spine and surface topography system. RESULTS: We found a significant increase in thoracic kyphosis during the course of pregnancy, but no increased lumbar lordosis. The lateral deviation of the spine also decreased significantly. However, we did not measure significant changes of the pelvic position during or after pregnancy. CONCLUSIONS: The results of our study show that pregnancy has an effect on the spinal posture, and that spine and surface topography can be used to measure these changes three-dimensionally and without any harmful radiation. In future studies this technique could allow to further evaluate the relationship between posture and low back pain during pregnancy, helping to understand the aetiology of low back pain in pregnancy as well as to identify methods for its prevention and treatment.

Effects of athletic training on the spinal curvature in child athletes.

The purpose of this study was to examine the spinal posture in young athletes depending on training intensity. The spinal curvature of 245 children, age 8 to 12 years, was evaluated using rasterstereography. According to their weekly training time group 1 (mean age: 9.54 ± 1.18) did 2-6, group 2 (mean age: 9.49 ± 0.87) did 6-15 and group 3 (mean age: 9.68 ± 0.87) did over 15 hours of training. Group 1 had a significantly higher weight (p = 0.028) (33.86 ± 7. kg) than those of the more active groups (30.67 ± 6.49 kg and 29.46 ± 4.33 kg). The mean kyphotic angle decreased significantly (p < 0.001) with the amount of training per week from 46.86 ± 8.2° in group 1 to 40.08 ± 8° in group 3. We also found a significant decrease (p = 0.047) in lateral deviation with training from group 1 with 5.3 ± 3 mm to group 2 with 4.1 ± 1.6 mm. The results of our study suggest that higher training time can be associated with lower weight and decreases in thoracic kyphosis and lateral deviation of the spine.

DELLAs regulate chlorophyll and carotenoid biosynthesis to prevent photooxidative damage during seedling deetiolation in Arabidopsis.

In plants, light represents an important environmental signal that triggers the production of photosynthetically active chloroplasts. This developmental switch is critical for plant survival because chlorophyll precursors that accumulate in darkness can be extremely destructive when illuminated. Thus, plants have evolved mechanisms to adaptively control plastid development during the transition into light. Here, we report that the gibberellin (GA)-regulated DELLA proteins play a crucial role in the formation of functional chloroplasts during deetiolation. We show that Arabidopsis thaliana DELLAs accumulating in etiolated cotyledons derepress chlorophyll and carotenoid biosynthetic pathways in the dark by repressing the transcriptional activity of the phytochrome-interacting factor proteins. Accordingly, dark-grown GA-deficient ga1-3 mutants (that accumulate DELLAs) display a similar gene expression pattern to wild-type seedlings grown in the light. Consistent with this, ga1-3 seedlings accumulate higher amounts of protochlorophyllide (a phototoxic chlorophyll precursor) in darkness but, surprisingly, are substantially more resistant to photooxidative damage following transfer into light. This is due to the DELLA-dependent upregulation of the photoprotective enzyme protochlorophyllide oxidoreductase (POR) in the dark. Our results emphasize the role of DELLAs in regulating the levels of POR, protochlorophyllide, and carotenoids in the dark and in protecting etiolated seedlings against photooxidative damage during initial light exposure.

Does age affect the response of pelvis and spine to simulated leg length discrepancies? A rasterstereographic pilot study.

PURPOSE: The purpose of this study was to investigate age differences in the response of the spine and pelvis to simulated leg length inequalities (LLIs). METHODS: A total of 107 subjects, separated into three age groups (group 1: 20-39 years, group 2: 40-59 years, group 3: >60 years), were used to evaluate for any age effects in the response to LLIs. LLIs of +10, +20, and +30 mm were simulated with a simulation platform on both sides, and the respective changes of pelvic position (pelvic obliquity, pelvic torsion) and spinal posture (lateral deviation, surface rotation, kyphotic, and lordotic angles) were measured with a rasterstereographic system. RESULTS: In all three age groups an increase in LLI led to significant changes in the pelvic position as measured by the parameters of pelvic obliquity and torsion. No significant differences in the response of the pelvis to the LLIs were found between the age groups. In all age groups an increase in surface rotation and lateral deviation of the spine with increasing LLIs was found. However, none of these parameters responded significantly different between the three age groups. CONCLUSIONS: Under static conditions, LLIs lead to significant changes of the pelvic position and spinal posture. Despite all known age-related changes, no significant differences of the measured pelvic and spinal parameters in elderly patients as a response to the simulated LLIs occurred.

Determining recovery of marine water quality of the Rio Doce using statistical and temporal comparisons with nearby river systems.

The Fundão dam breach affected the Rio Doce's estuarine and marine environments with water, tailings, scoured soil and/or sediments, and other debris. Time series and standard exceedance analyses are typically used to assess water quality recovery to baseline conditions after deteriorating water quality events. In the absence of historical measurements, impacts to water quality from the Fundão Event were compared with measurements of nearby rivers. Similar river systems with available water quality measurements were grouped into affected and unaffected estuarine and marine waters. Statistical and temporal comparisons of marine waters unaffected by the Rio Doce with those affected by the Rio Doce were evaluated for systematic differences. Multivariate statistical techniques were also used to assess water quality differences. Our results demonstrate that the Fundão dam breach had a short-term water quality impact on marine waters near the Rio Doce mouth. Principal component and comparative time series analyses clearly demonstrated this impact during the 2015/2016 and 2016/2017 wet seasons. The ephemeral effects of the breach, however, did not compromise marine water quality. Exceedances of CONAMA standards for metals remained either at zero or at very low levels during the affected period (<5.7%). Before the start of the next wet season in October 2017, water quality impacts from the Event were statistically indistinguishable from unaffected marine waters, indicating recovery to baseline conditions. Integr Environ Assess Manag 2024;20:99-116. © 2023 NewFields Companies, LLC. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Applying multivariate techniques to fingerprint water quality impact of the Fundão Dam breach within the Rio Doce basin.

The Fundão Dam breach on 5 November 2015 (the "Event") released tailings, water, soil and/or sediments, and other debris to downstream watercourses. This breach included both direct and indirect impacts from scouring of soils and sediments along and within the affected courses. Multivariate statistical techniques were used to determine the potential of fingerprinting the impact of the breach compared to pre-Event water quality conditions and unaffected watercourses. The selection of key parameters is an important first step for multivariate analyses. Analysis of too many parameters can mask important trends and relationships, while analysis of too few may miss significant water quality indicators. A two-phased selection process was used to identify key parameters that indicated impact from the Event: (a) unbiased, principal component analysis to extract chemically dominant profiles among all measured parameters and (b) comparison of metals' concentrations between unaffected soils and/or sediments and tailings samples. Radar charts of key parameters along with statistical comparisons to pre-Event and not-affected waterways were then aggregated over space and time to assess impact and potential recovery to pre-Event conditions. Nine parameters were identified that characterize tailings-related (direct) and background soil and/or sediment-related (indirect) impacts. Spatially and temporally aggregated radar charts and nonparametric Mann-Whitney U tests were used to assess the statistical significance of these impacts during each wet season since the breach. Indirect parameters, like aluminum and lead, returned to pre-Event levels in the first wet season after the Event. By the 2018/2019 wet season, most of the direct and indirect parameters had returned to pre-Event levels. Integr Environ Assess Manag 2024;20:133-147. © 2023 NewFields Companies, LLC. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Using spatiotemporal ratio analyses to quantitatively estimate water quality recovery of the Rio Doce.

The Fundão Dam breached on 5 November 2015 (the "Event"), resulting in the release of tailings, water, scoured sediment and/or soil, and other debris to downstream watercourses. Statistical analyses using historical and recent water quality measurements were conducted to assess the extent to which water quality in the Rio Doce was recovering to baseline conditions. A review of station- and/or parameter-specific water quality time series in the Rio Doce revealed two challenges: pre-Event data imbalance and seasonality. Due to the combined effects of these two factors, data gathered from Rio Doce water quality stations before the Event likely underestimated concentration ranges and limited the usefulness of common recovery assessment techniques such as times series and water quality standard exceedance analyses. These challenges were addressed by calculating quarterly and watershed-specific river-to-tributary ratios. R code was used to produce spatiotemporal time series for 44 investigated parameters that were measured both before and after the Event. The water quality recovery durations shown by the parameter- and/or region-specific river-to-tributary ratio time series indicated that (a) turbidity provides the most conservative measure for water quality recovery; (b) chemical parameters associated with the tailings, like manganese and iron recovered faster than turbidity; and (c) other investigated parameters unrelated to the tailings showed either no discernable impact or rapid recovery after the Event. The resulting parameter- and/or region-specific river-to-tributary ratio time series provided reliable and quantifiable estimates of water quality recovery durations. The water quality in the region furthest from Fundão Dam, in Espírito Santo, recovered one year after the Event, while water quality in the closest region to Fundão Dam, upstream of Risoleta Neves (Candonga) Dam, recovered 4.2 years after the Event. Integr Environ Assess Manag 2024;20:74-86. © 2023 Newfields Companies, LLC. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Patient-specific implants made of 3D printed bioresorbable polymers at the point-of-care: material, technology, and scope of surgical application.

BACKGROUND: Bioresorbable patient-specific additive-manufactured bone grafts, meshes, and plates are emerging as a promising alternative that can overcome the challenges associated with conventional off-the-shelf implants. The fabrication of patient-specific implants (PSIs) directly at the point-of-care (POC), such as hospitals, clinics, and surgical centers, allows for more flexible, faster, and more efficient processes, reducing the need for outsourcing to external manufacturers. We want to emphasize the potential advantages of producing bioresorbable polymer implants for cranio-maxillofacial surgery at the POC by highlighting its surgical applications, benefits, and limitations. METHODS: This study describes the workflow of designing and fabricating degradable polymeric PSIs using three-dimensional (3D) printing technology. The cortical bone was segmented from the patient's computed tomography data using Materialise Mimics software, and the PSIs were designed created using Geomagic Freeform and nTopology software. The implants were finally printed via Arburg Plastic Freeforming (APF) of medical-grade poly (L-lactide-co-D, L-lactide) with 30% ß-tricalcium phosphate and evaluated for fit. RESULTS: 3D printed implants using APF technology showed surfaces with highly uniform and well-connected droplets with minimal gap formation between the printed paths. For the plates and meshes, a wall thickness down to 0.8 mm could be achieved. In this study, we successfully printed plates for osteosynthesis, implants for orbital floor fractures, meshes for alveolar bone regeneration, and bone scaffolds with interconnected channels. CONCLUSIONS: This study shows the feasibility of using 3D printing to create degradable polymeric PSIs seamlessly integrated into virtual surgical planning workflows. Implementing POC 3D printing of biodegradable PSI can potentially improve therapeutic outcomes, but regulatory compliance must be addressed.

Determination of the amount of leg length inequality that alters spinal posture in healthy subjects using rasterstereography.

PURPOSE: Leg length inequalities (LLIs) can result in an increased energy consumption, abnormal gait or osteoarthritis of the hip. In a previous study we simulated different LLIs of up to 15 mm and evaluated their effects on the pelvic position and spinal posture. We found a correlation between LLIs and resulting changes of the pelvic position. Despite suggestions in the literature we were not able to detect significant changes of the spinal posture. Therefore, the purpose of this study was to determine the amount of LLI that would in fact alter the spinal posture. METHODS: The subjects were placed on a simulation platform, whose height could be precisely controlled by the measuring device, to simulate different LLIs of up to 20 mm. For LLIs >20 mm, additional precision-cut wooden blocks were used under one foot. After an adaptation period the resulting changes of the pelvis and spine were measured with a rasterstereographic device. RESULTS: We found a significant correlation between platform height changes and changes of the pelvic position. The frontal spinal parameters surface rotation and lateral deviation changed significantly when simulating differences greater than 20 mm. No changes of the sagittal spinal curvature were measured, however, a trend to decreasing kyphotic angles was noted. CONCLUSIONS: Our study has shown for the first time that LLIs >20 mm will lead to significant changes in the spinal posture of healthy test subjects. However, these changes were only found in frontal (surface rotation and lateral flexion) spinal parameters, but not in sagittal parameters. Here for the kyphotic angle only a tendency to decreasing angles was noted. We have also found a significant correlation between different leg lengths and changes of the pelvic position. Further, females and males seem to react in the same way to LLIs.