Shaft Width Research Articles

Treatment concepts for the medial clavicle and the sternoclavicular joint

Medial clavicle fractures and injuries to the sternoclavicular joint are rare injuries but can have life-threatening consequences. There are no standardized treatment algorithms or guidelines for the diagnostics and treatment. This article provides an overview of the individual topographies as well as the conservative and surgical treatment strategies.Conservative treatment is preferred for medial clavicle fractures. The indications for surgical treatment are variable but this is frequently carried out if there is a fracture displacement > 1 cm or1 shaft width and high functional demands. In the case of accompanying injuries to neurovascular structures, an open fracture or the threat of perforation of the skin, surgical treatment is mandatory. Open reduction and internal fixation using (locking) plates is currently the preferred form of treatment.In the case of posterior dislocation of the sternoclavicular joint, an immediate closed reduction must be attempted with the patient under analgosedation and with emergency treatment on standby. This temporal urgency does not exist for anterior and superior dislocations. Surgical treatment is indicated in cases of unsuccessful reduction, persistent symptomatic instability or injuries of the neurovascular bundle. From a multitude of treatment options, arthrodesis with suture cerclage has shown good results. Tendon grafts as well as special hook plates are increasingly being used due to better biomechanical qualities. The surgical treatment of combined injuries is determined by the individual injury pattern.Despite the variety of treatment strategies, the long-term outcome has consistently been positively described.

Scanning electron microscopy and morphometric analysis of the hair in dromedaries with SEM-EDX in relation to age

BackgroundHair characterization is critical for determining animal individuality throughout life. This study aimed to assess the morphological features of dromedary camel hair in relation to age.Materials and methodsHair samples were obtained from the camel humps of 30 dromedary camels separated into three groups: G1 (n:10) aged one-year, G2 (n:10) aged 3–5 years, and G3 (n:10) at the age of 8–10 years. The hair was examined using light microscopy, SEM, and SEM-EDX.ResultsThe Maghrebi camel had varied medulla patterns and structures across the ages. In the G1 group 75% had continuous medulla patterns and amorphous medulla structures, compared to 70% in G2, and 90% in G3. The medulla index increased with age, rising from 0.3 to 0.77%. The shaft width grew in size from G1 to G2, then fell to approximately one-third of the G2 size at G3. The cortex and cuticle widths were also determined by age, and they increased in the G1 compared to G3 camels. The shape of the cuticle scales in G1 camels was wavy, like mountain tops with irregular edges, within G2 camels the scales were particularly long, oval-shaped scales with smooth, wavy borders. The scales of the older G3 camels were quite long and rectangular. SEM-EDX spectra recognized carbon, oxygen, nitrogen, sulfur, calcium, aluminum, silicon, and potassium at the medulla and cortex. Sulfur levels were highest in the G2 samples but lowest in the G1 samples.ConclusionThe dromedary camel’s hair structure and mineral content, particularly carbon and nitrogen, differed as camels aged.

Radiographic Features of the Metacarpal in Blauth Type III Thumb Hypoplasia

The purpose of this study was to investigate whether radiographs can be used to aid in the determination of Blauth IIIA and IIIB thumbs. Six pediatric hand surgeons were asked to evaluate the radiographs of 77 thumbs and classify the thumb as IIIA or IIIB and indicate which morphologic features influenced their decision. Quantitative measurements and ratios of radiographs were obtained and compared between IIIA and IIIB thumbs. The radiographic features selected for type IIIA thumbs include near-normal length and near-normal width and for type IIIB thumbs, abnormally short, tapered proximal end, and round proximal end. The six surveyed surgeons reached consensus in 82% (63/77) of thumbs, and this matched the enrolling surgeon's classification in 77% (59/77) cases. The ratio of the length of the thumb metacarpal compared with the length of the index metacarpal was different between IIIA and IIIB thumbs (66% ± 0.08% and 46% ± 0.18%, respectively). The ratio of the width of the thumb metacarpal shaft at its narrowest aspect to the width of the thumb metacarpal base was notably different between IIIA and IIIB (68% ± 0.13% and 95% ± 0.28%, respectively). Near-normal length and near-normal width of the metacarpal were used to predict IIIA and abnormally short, abnormally narrow, and a round or tapered base of the metacarpal were used to predict IIIB classification. The length of the thumb metacarpal relative to the index metacarpal is on average 66% of the length of the index metacarpal in IIIA thumbs compared with 46% in IIIB thumbs. The width of the shaft of the thumb metacarpal at its narrowest is 68% of the width of the thumb metacarpal base in IIIA thumbs, indicating a flared base. In IIIB thumbs, the shaft width was on average 95% of the base width, indicating a tapered base. Diagnostic level III.

Treatment of proximal humeral fractures in childhood and adolescence : Consensus report of the pediatric traumatology section of the German Society for Trauma Surgery

Proximal humeral fractures are arelatively common injury in childhood and adolescence, accounting for 0.45-2% of all fractures [2, 18]. Treatment is usually conservative but is still the subject of ascientific debate [9, 12]. In addition to the S1-LL, there are different recommendations for the diagnostics and treatment of these fractures in the literature. As part of the 10thscientific meeting of the SKT of the DGU, the existing recommendations and the relevant or current literature were critically discussed by apanel of experts and aconsensus was formulated. An algorithm for the diagnostics, therapy and treatment was integrated into this. The measurement of axial deviation and tilt is not interobserver and intraobserver reliable [3]. The age limit for when complete correction is possible was set at an age of 10years, as the correction potential changes around this age. For diagnostic purposes, well-centered X‑ray images in 2planes (true AP and Y‑images without thoracic parts) is defined as the standard. At the age of less than 10years, any malposition can be treated conservatively with Gilchrist bandaging for 2-3weeks. Surgery can only be indicated in individual cases, e.g., in the event of severe pain or the need for rapid weight bearing. An ad latus displacement of more than half the shaft width should not be tolerated over the age of 10years. Due to the variance in the measurement results, it is not possible to recommend surgical treatment depending on the extent of the ad axim dislocation. As aguideline, the greater the dislocation and the closer the child is to growth joint closure, the more likely surgical treatment is indicated. The development should be taken into account. The gold standard is retrograde, radial and unilateral ESIN osteosynthesis using two intramedullary nails. Osteosynthesis does not require immobilization. Afollow-up X‑ray is planned for unstable fractures without osteosynthesis after 1week, otherwise optional for documentation of consolidation after 4-6weeks, e.g., if sports clearance is to be granted and before metal removal (12weeks). Recommendations for surgical indications based on the extent of tilt are not reproducible and seem difficult in view of the current literature [3, 9, 12]. Apragmatic approach is recommended. The prognosis of the fracture appears to be so good, taking the algorithm into account, that restitutio ad integrum can be expected in most cases.

Effect of unpowered ventilation caps and shaft parameters on fire smoke spread in the natural ventilation tunnel with shafts

Shaft-type natural ventilation offer a sustainable and cost-effective alternative to mechanical systems for the mitigation of smoke hazards. This study investigated the behavior of smoke with the application of unpowered ventilation caps in 1/15 scale shallow-buried urban road tunnels with shafts, and analyzed parameters such as the shaft axis wheelbase, shaft width, shaft width-to-height ratio, and heat release rate (HRR). The results show that the dimensionless HRR as an independent relationship with the dimensionless ceiling temperature rise in both the presence and absence of the unpowered ventilation cap. According to the experimental results, dimensionless length of smoke backlayering increases significantly with the increase of the HRR. In addition, the smoke backlayering length is positively correlated with the shaft width, and the backlayering length decreases and then increases with increases of the axis wheelbase. Moreover, the chimney effect is facilitated with the shaft height increase, which enhances exhaust effect, and the backlayering length decreases with the increase in the shaft height when the aspect ratio is greater than 0.5. Once the critical shaft width-to-height ratio is reached, the change in the shaft height no longer has an effect on the backlayering length. Finally, a dimensionless backlayering length calculation model based on the shaft parameters with different shaft exhaust effects is developed by combining the discriminant factors. The findings have crucial implications for fire prevention and safety management, and provide a valuable reference for future studies and engineering applications.

Objective documentation of hypospadias anatomy with three-dimensional scanning

The absence of a standardized classification of hypospadias hinders understanding of the anatomic differences among patients and the evaluation of outcomes following surgical repair. In working towards a standardized, objective method of recording patients' hypospadias anatomy, we describe our initial experience using a non-invasive three-dimensional scanner. An Artec3D Space Spider scanner was used to obtain 3D scans in 29 patients undergoing hypospadias repair. Measurements of the urethral plate width, urethral plate length, glans width, penile shaft length, and penile shaft width were made by 2 pediatric urology attendings and 1 pediatric urology fellow. Measurements were compared and inter-rater reliability was calculated. A total of 435 measurements were made on 29 successfully generated 3D scans, ranging from distal to proximal hypospadias. The inter-rater reliability of measurements from the generated 3D models shown good inter-rater reliability of urethral plate width (ICC0.87 [95%CI:0.76,0.93]), penile shaft length (ICC0.87 [95%CI:0.70,0.94]) and glans width (ICC0.83 [95%CI:0.68,0.92]), excellent inter-rater reliability of urethral plate length (ICC0.96) and moderate inter-rater reliability of penile shaft width (ICC0.69 [95%CI:0.44,0.84]). There was a high degree of reliability of measurements made across multiple users. Calculation of the ratio of the urethral plate length/total penile shaft length objectively defined the initial position of the urethral meatus. When compared to the 3-dimensional volume of the glans, a more proximally positioned urethral meatus was associated with a lower glans volume. 3D scanning offers a rapid, reproducible, and non-invasive method of documenting hypospadias anatomy. The ability to evaluate three dimensional features (i.e. glans volume) offers an exciting opportunities for robust investigation of hypospadias outcomes and further understanding of the relationship between a patient's genotype and phenotype.

Biomechanical Evaluation of 4th Generation Minimally Invasive Distal First Metatarsal Osteotomy-Akin Osteotomy Technique on First Ray Articular Contact Properties

Category: Bunion; Basic Sciences/Biologics Introduction/Purpose: Hallux valgus is a common deformity encountered, but remains a complex clinical entity. Fourth generation minimally invasive (MIS) techniques consisting of a percutaneous distal metatarsal transverse osteotomy combined with an Akin osteotomy have been utilized to address mild to severe hallux valgus deformities. Benefits of a MIS approach include improved cosmesis, faster recovery, lower opiate requirement, immediate weightbearing, and favorable outcomes relative to a traditional, open procedure. An understudied area with respect to hallux valgus correction is the effect that osteotomies can have on the articular contact properties of the first ray following correction. Methods: Sixteen paired cadaveric specimens were dissected to include the first ray and tested in a customized apparatus. Specimens were randomized to receive a distal transverse osteotomy translated either 50% or 100% of the width of the first metatarsal shaft. The osteotomy was performed with either a 00or 200 distal angulation of the burr relative to the shaft in the axial plane. Specimens were tested in the intact state and following the distal first metatarsal osteotomy for peak pressure, contact area, contact force and center of pressure at the first metarsophalangeal joint (MTP) and first tarsometatarsal joint (TMT). An Akin osteotomy was then performed on each specimen and peak pressure, contact area, contact force and center of pressure were recalculated. Results: There was a notable decrease in peak pressure, contact area, and contact force across the TMT joint with greater shifts of the capital fragment. However, at 100% translation of the capital fragment, distal angulation of the osteotomy by 200 appears to improve loading across the TMT joint. Addition of the Akin osteotomy at 100% translation also aids in increasing the contact force across the TMT joint. The MTP joint is less sensitive to changes in shifts and angulation of the capital fragment. The Akin osteotomy also leads to increased contact force across the MTP joint when the capital fragment is translated 100%. Conclusion: While the clinical significance is unknown, larger shifts of the capital fragment lead to greater load alterations at the level of the TMT joint than the MTP joint. Distal angulation of the capital fragment and the addition of an Akin osteotomy can aid in reducing the size of those changes. The Akin can lead to increased contact forces at the MTP joint with 100% translation of the capital fragment.

Fractures around the shoulder in the skeletally immature: A scoping review.

Fractures around the shoulder girdle in children are mainly caused by sports accidents. The clavicle and the proximal humerus are most commonly involved. Both the clavicle and the proximal humerus have a remarkable potential for remodeling, which is why most of these fractures in children can be treated conservatively. However, the key is to understand when a child benefits from surgical management. Clear indications for surgery of these fractures are lacking. This review focuses on the available evidence on the management of clavicle and proximal humerus fractures in children. The only strict indications for surgery for diaphyseal clavicle fractures in children are open fractures, tenting of the skin with necrosis, associated neurovascular injury, or a floating shoulder. There is no evidence to argue for surgery of displaced clavicle fractures to prevent malunion since most malunions are asymptomatic. In the rare case of a symptomatic malunion of the clavicle in children, corrective osteosynthesis is a viable treatment option. For proximal humerus fractures in children, treatment is dictated by the patient's age (and thus remodeling potential) and the amount of fracture displacement. Under ten years of age, even severely displaced fractures can be treated conservatively. From the age of 13 and onwards, surgery has better outcomes for severely displaced (Neer types III and IV) fractures. Between 10 and 13 years of age, the indications for surgical treatment are less clear, with varying cut-off values of angulation (30-60 degrees) or displacement (1/3 - 2/3 shaft width) in the current literature.

Current standard of care for distal femur fractures in Germany and Switzerland

BackgroundDistal femur fractures occur with an incidence of 4.5/100,000 and show a prevalence of 0.4%. Causes include low-impact trauma in older patients and high-impact trauma in younger patients without pre-existing medical conditions. The aim of this study was to perform a comprehensive evaluation of trauma mechanisms, trauma-promoting factors, comorbidities, medication history and type of surgical care to provide an overview of the causes of injury and the most appropriate therapeutic approach. MethodsIn this multicenter cohort study a retrospective analysis of 229 patients who sustained a distal femur fracture between January 2011 and December 2020 was performed. Individual fracture patterns, fracture predisposing factors, concomitant disease profiles, medication history, treatment strategy and associated complications were analyzed. Results229 patients were included in the retrospective analysis. A total of 113-type 33 A, 50-type 33 B and 66-type 33 C fractures were diagnosed, of whom 92% received a lateral locking plate osteosynthesis. There was a complication in 14.4% of all cases, of which 6.1% were attributable to infection. Significant risk factors for developing a complication were an increased BMI (29.9 ± 8.5 kg/m2; p = 0.04), fracture displacement of over half a shaft width (p < 0.001) and AOC fractures (p < 0,016), specifically C2 fractures (p < 0,008). ConclusionIn this multicenter retrospective cohort study, lateral locking plate osteosynthesis was the method of choice and was selected in over 90% of cases, regardless of the fracture classification and risk factors. A complication rate of 14.4% emphasizes the necessary analysis of patient- and care-specific risk factors and a resulting adjustment of the therapy strategy. An increased BMI (29.9 ± 8.5 kg/m2; p = 0.04), fracture displacement of over half a shaft width (p < 0.001) and AOC fractures (p < 0,016), specifically C2 fractures (p < 0,008) increase the risk of developing a complication and should prompt an early switch to a treatment strategy that provides more stability.

Biomechanical Evaluation of Fourth Generation Minimally Invasive Distal First Metatarsal Osteotomy-Akin Osteotomy Technique on First Ray Articular Contact Properties.

Hallux valgus is a common deformity encountered but remains a complex clinical entity. Fourth-generation minimally invasive surgery (MIS) techniques consisting of a percutaneous distal metatarsal transverse osteotomy combined with an Akin osteotomy have been used to address mild to severe hallux valgus deformities. The benefits of an MIS approach include improved cosmesis, faster recovery, lower opiate requirement, immediate weightbearing, and favorable outcomes relative to a traditional, open procedure. An understudied area with respect to hallux valgus correction is the effect that osteotomies can have on the articular contact properties of the first ray following correction. Sixteen paired cadaveric specimens were dissected to include the first ray and tested in a customized apparatus. Specimens were randomized to receive a distal transverse osteotomy translated either 50% or 100% of the width of the first metatarsal shaft. The osteotomy was performed with either a 0° or 20° distal angulation of the burr relative to the shaft in the axial plane. Specimens were tested in the intact state and following the distal first metatarsal osteotomy for peak pressure, contact area, contact force and center of pressure at the first metatarsophalangeal (MTP) and first tarsometatarsal (TMT) joints. An Akin osteotomy was then performed on each specimen, and peak pressure, contact area, contact force, and center of pressure were recalculated. There was a notable decrease in peak pressure, contact area, and contact force across the TMT joint with greater shifts of the capital fragment. However, at 100% translation of the capital fragment, distal angulation of the osteotomy by 20° appears to improve loading across the TMT joint. Addition of the Akin osteotomy at 100% translation also aids in increasing the contact force across the TMT joint. The MTP joint is less sensitive to changes in shifts and angulation of the capital fragment. The Akin osteotomy also leads to increased contact force across the MTP joint when the capital fragment is translated 100%. While the clinical significance is unknown, larger shifts of the capital fragment lead to greater load alterations at the level of the TMT joint than the MTP joint. Distal angulation of the capital fragment and the addition of an Akin osteotomy can aid in reducing the size of those changes. The Akin can lead to increased contact forces at the MTP joint with 100% translation of the capital fragment. Not applicable, Biomechanical study.

Simulation research on fretting wear of train axles with interference fit based on press-fitted specimen

Based on dimensional analysis and similarity theorem, this paper deduces the scaling relationship considering the fretting fatigue problem of the wheel and axle, and verifies it through finite element simulation analysis. A finite element model of a 1/10 reduction ratio press-fit specimen was established to simulate the fretting characteristics of the interference fit of the train axle, and the ABAQUS finite element software combined with the Fortran wear subroutine Umeshmotion was used to apply the rotational bending load. Only considering the cumulative effect of fretting wear in the slip zone, the variation characteristics of the wear width and depth of the specimen shaft with the number of load cycles were studied. The simulation results show that the fretting wear area and wear depth increase with the increase of the number of load cycles, and the axial width of the wear area of the contact surface is about 0.2 mm; the existence of the overlap of the specimen hub can restrain the position of the contact edge of the specimen shaft fretting wear effect. This makes the maximum wear depth of the specimen shaft occur at 0.03 mm from the contact edge, while the maximum wear depth of the specimen hub contact area occurs at the contact edge.

Influence of Underground Excavation Expansion on Surrounding Rock Characteristics at Intersection of Ventilation Shaft and Tunnel: A Case Study

Existing railways can no longer meet transportation requirements, and it is an urgent need to expand old tunnels. However, the existence of ventilations shaft makes expansions face greater risks. This study analyzed the tangential stress change trend during the expansion process through field monitoring, and numerical simulation was used to analyze the changes in stress and displacement under different shaft depths and width–span ratios. The results show that as one approaches the tunnel face, the tangential stress in the arch foot and side wall of the J-2 and J-3 sections gradually increased, and the tangential stress in the arch foot and side wall of the J-1 section gradually decreased. The distance of the tunnel expansion’s influence on tangential stress is about 0.91 to 1.45 times the tunnel span. The largest value of vertical displacement had a linear relationship with shaft depth, and the largest value of horizontal displacement had a quadratic relationship with shaft depth. Changes in the width–span ratio only had a greater impact on the ventilation shaft section. These results can provide a reference for similar in situ expansion projects.

Design of three-section microneedle towards low insertion force and high drug delivery amount using the finite element method

A microneedle has been greatly recognized as one of the most promising devices for novel transdermal drug delivery system due to its capacity of piercing the protective stratum corneum with a minimally invasive and painless manner. During the past two decades, although numerous achievements have been made in the structure and material combination of microneedles, they mostly focus on the pharmacology and functionality of microneedles, and little is reported about how to design the shape of microneedles to reduce insertion force and especially improve penetration efficiency. Using the developed finite element method, we designed three-section microneedles (TSMN) with various sizes and evaluated their maximum insertion force, penetration efficiency, drug delivery amount and strength. The simulation results demonstrate that the well-designed TSMN with shaft width of 60 μm exhibits a lower maximum insertion force of 116.68 mN relative to 167.92 mN of conical microneedle and an effective penetration length of 81.6% relative to 71.38% of conical microneedle. Besides, the optimized TSMN with shaft width of 80 μm shows similar maximum insertion force and 2.3 times the drug delivery amount compared to conical microneedle. These excellent properties are attributed to the optimized design of the shape curve of TSMN sidewall. Such results may provide an inspiration of microneedle design for low insertion force and high penetration efficiency.

Clavicle shaft fractures in childhood and adolescence : Consensus report of the Pediatric Traumatology Section of the German Society for Trauma Surgery

Clavicle shaft fractures are among the most common fractures in childhood and adolescence. In the past they were almost exclusively treated conservatively but in recent years there has been an increase in surgical treatment. Nevertheless, exact recommendations for the choice of diagnostics and for the treatment regimen do not yet exist. Therefore, our aim was to develop aconsensus within the 7th scientific working meeting of the section for pediatric traumatology in the German Society for Trauma Surgery based on expert opinion. Single-plane radiographic imaging is considered the gold standard diagnostic tool. Children younger than 10years are primarily treated conservatively, and the type of immobilization is secondary. In girls older than 12years and boys older than 14years, fractures dislocated by more than the shaft width and shortened by > 2 cm should be treated by open reduction and stabilized by osteosynthesis, followed by free-functional follow-up treatment. In addition to X‑rays, diagnostics using ultrasound must be further established. Treatment continues to be primarily conservative, but surgical treatment is also important, especially in adolescents. If the indications are correct, agood outcome can be expected regardless of the choice of treatment.

Performance scanning electron microscopic investigations and elemental analysis of hair of the different animal species for forensic identification.

Veterinary forensics have attracted less attention compared with human forensics. Animal hair morphological examination using scanning electron microscopy (SEM) and hair mineral analysis using energy-dispersive X-ray fluorescence (ED-XRF) provide reference databases for animal hair identification used in forensic investigations. This study was performed on four different animal species: large ruminants (buffalo and cattle), small ruminants (goat and sheep), carnivores (cat and dog), and equines (donkey and horse). The hair scale pattern, scale margin type, and distance between scales were identified. The hair scale pattern was imbricate in large ruminants, goat, and horse; coronal (crown-like) in carnivores and donkey; and spinous in sheep. The morphometric measurements, including cuticle layer thickness, cuticle scale height, cortex diameter, and hair shaft width were recorded. The highest cuticle thickness was found in horse, and the highest cuticle hair scale was detected in cattle. Moreover, the largest cortex diameter was measured in buffalo, whereas the smallest one was in cat. With regard the content of hair elements, some elements were specific for the hair of certain tested animals, such as bromine in sheep and magnesium and phosphorus in buffalo. In addition, vanadium and titanium were found only in cattle and dog, and the latter element was also detected in sheep. In conclusion, this study provides two techniques for animal hair identification that can be used in forensic investigations. RESEARCH HIGHLIGHTS: Hair scale pattern was imbricate in (large ruminants, goat, and horse); coronal in (carnivores and donkey); and spinous in (sheep) with different scale margins type. Hair shaft width in all tested animal species ranged from 23.78 ± 1.24 μm to 85.51 ± 1.14 μm.

Influence of dietary supplementation of selenium and vitamin E on bone morphometry and mineralization in broiler chicken under heat stress

A study on bone development under the influence of selenium and vitamin E supplementation was under taken in broiler chicken. Three levels of each selenium (0.15, 0.35, and 0.45 mg/kg diet) and vitamin E (50, 100, and 150 IU/ kg diet) were taken to formulate nine treatment groups in the form of broiler starter and finisher to evaluate the bone morphometry and bone mineralization of broiler chicken. The experiment was conducted in a high temperature humidity index (83.94) during the August-September period. The results revealed that bone morphometry parameters such as tibia bone proximal width, mid shaft width, distal width, and length were not influenced by dietary selenium and vitamin E supplementation. Similarly, the mean tibia bone weight (g), bone moisture (%), bone calcium (%), bone phosphorus (%), total ash (%), and bone Zn content (mg/kg) did not differ significantly due to selenium and vitamin E levels in the diet. Therefore, it can be concluded that the bone morphometry and bone mineralization in broiler chicken is not affected by different levels of selenium and vitamin E in the diet.

Blue light-emitting diodes in hair regrowth: the first prospective study.

Different studies highlight photo-receptors' presence on the hair follicle that seems to be capable of eliciting hair growth. This study aims to demonstrate blue light's effectiveness on hair growth in patients affected by androgenetic alopecia. Twenty patients enrolled at Magna Graecia University Unit of Dermatology, affected by androgenetic alopecia, were treated with a blue LED light device at 417 ± 10nm, fluence of 120J/cm2, and power intensity of 60 mW/cm2 ± 20%. The treatments were performed twice a week for ten consecutive weeks. Patients were evaluated before and 1month after the end of therapy clinically using standardized global photographs and dermoscopically estimating hair density and hair shaft width. An increase in hair density and hair shaft width was recorded in 90% of patients after 10weeks. Photographic improvement was noted in 80% of the patients. No serious adverse events have been reported. The only side effect consisted in a darkening of the hair, perhaps due to melanic stimulation due to blue light in 2 patients. Blue light therapy is a promising therapy for patients affected by androgenetic alopecia and other diseases characterized by hair loss. Further studies will be necessary to confirm the findings of this preliminary study.

C-arm orbits for metal artifact avoidance (MAA) in cone-beam CT

Metal artifacts present a challenge to cone-beam CT (CBCT) image-guided surgery, obscuring visualization of metal instruments and adjacent anatomy—often in the very region of interest pertinent to the imaging/surgical tasks. We present a method to reduce the influence of metal artifacts by prospectively defining an image acquisition protocol—viz., the C-arm source-detector orbit—that mitigates metal-induced biases in the projection data. The metal artifact avoidance (MAA) method is compatible with simple mobile C-arms, does not require exact prior information on the patient or metal implants, and is consistent with 3D filtered backprojection (FBP), more advanced (e.g. polyenergetic) model-based image reconstruction (MBIR), and metal artifact reduction (MAR) post-processing methods. The MAA method consists of: (i) coarse localization of metal objects in the field-of-view (FOV) via two or more low-dose scout projection views and segmentation (e.g. a simple U-Net) in coarse backprojection; (ii) model-based prediction of metal-induced x-ray spectral shift for all source-detector vertices accessible by the imaging system (e.g. gantry rotation and tilt angles); and (iii) identification of a circular or non-circular orbit that reduces the variation in spectral shift. The method was developed, tested, and evaluated in a series of studies presenting increasing levels of complexity and realism, including digital simulations, phantom experiment, and cadaver experiment in the context of image-guided spine surgery (pedicle screw implants). The MAA method accurately predicted tilted circular and non-circular orbits that reduced the magnitude of metal artifacts in CBCT reconstructions. Realistic distributions of metal instrumentation were successfully localized (0.71 median Dice coefficient) from 2–6 low-dose scout views even in complex anatomical scenes. The MAA-predicted tilted circular orbits reduced root-mean-square error (RMSE) in 3D image reconstructions by 46%–70% and ‘blooming’ artifacts (apparent width of the screw shaft) by 20–45%. Non-circular orbits defined by MAA achieved a further ∼46% reduction in RMSE compared to the best (tilted) circular orbit. The MAA method presents a practical means to predict C-arm orbits that minimize spectral bias from metal instrumentation. Resulting orbits—either simple tilted circular orbits or more complex non-circular orbits that can be executed with a motorized multi-axis C-arm—exhibited substantial reduction of metal artifacts in raw CBCT reconstructions by virtue of higher fidelity projection data, which are in turn compatible with subsequent MAR post-processing and/or polyenergetic MBIR to further reduce artifacts.

A New Radiographic Method for Estimating Tibial Malrotation

Background: Diaphyseal tibial fractures are the most frequent bone fractures in the body and are usually treated with intramedullary nailing method. However, this approach is responsible for 41% of the rotational deviation. Objectives: This study aimed to provide a radiographic evaluation method to determine tibial malrotation in closed fixation of tibia bone fractures during or after the operation. Methods: This study was conducted in a university hospital from May 2015 to March 2016. All patients referring to the hospital with the complaints of minor trauma around the ankle and knee requiring radiographic evaluation of both joints were enrolled in the study. The inclusion criteria included being 20 and 50 years old; having normal axial, sagittal, and coronal lower limb alignment; lacking previous lower limb injury (such as fractures of the tibia or fibula), ankle or knee sprain; not having previous lower limb surgery, metabolic or congenital bone diseases, or malignancy. In all cases, a standard Anteroposterior (AP) radiograph of the knee was taken, and then, without changing the limb position or image setting, an AP radiograph of the ankle was obtained. The overlap between the distal tibia and fibula was measured in the PACS program environment. Results: Fifty cases were included in this study. The Mean±SD ages of males and females were 29.08±2.49 years and 31.46±2.04 years, respectively. The range of distal tibia-fibula overlap one centimeter above the tibiotalar joint line was 7.81 to 9.09 mm (confidence interval of 95%), and its percentage to the fibula shaft width at the same level was 49.43% to 54.35%. Conclusion: According to the results, distal tibia-fibula overlap when the knee is in the true AP position, regardless of the side and gender, is 7.81 to 9.09 mm or 49.43% to 54.35%.

Experimental study on the performance of hybrid ventilation system combining forced longitudinal flow and shaft natural ventilation in tunnels

The hybrid ventilation system combining forced longitudinal flow and shaft natural ventilation has the advantages of both ventilation strategies; for example, it can discharge buoyant smoke through the nearest downstream shaft and can actively constrain backlayering flow. A series of brine-water experiments were conducted to investigate the effects of the longitudinal velocity and shaft dimensions on the performance of the hybrid ventilation system in urban traffic tunnels. A light attenuation technique was used to obtain the width-averaged density distribution in the entire tunnel. Subsequently, ventilation efficiency and the backlayering length were easily determined. The results indicated that the extraction efficiency of the buoyant fluid decreases with increasing longitudinal velocity, particularly when the ventilation shaft is short and the longitudinal velocity is large. Moreover, the existence of a stable backlayering flow is useful for improving the extraction efficiency. For ordinary urban traffic tunnels that allow only passenger cars to pass through, the optimal height and width of the ventilation shaft were determined to be 9 and 7 m, respectively. From the results of the backlayering length and extraction efficiency, we observed that the acceptable longitudinal velocity corresponding to the optimal shaft dimensions approximately varies from 1.8 to 2.3 m/s. The study can provide useful information for the design of such hybrid ventilation systems in urban traffic tunnels.