Survey data on public perceptions towards flying cars and flying taxi services.

An online survey was conducted to evaluate public perceptions towards an emerging transportation technology, namely the flying car, which is expected to join the existing traffic fleet within the following decades. Responses from 692 survey participants were collected. Approximately 84% of the participants were from the United States, and the remaining 16% were from the rest of the world. The data resulting from the survey include several aspects of public perceptions towards flying cars, as for example: willingness to use and pay for flying cars; willingness to use and pay for flying taxi services; perceptions towards potential benefits and concerns arising from the future use of flying cars; perceptions towards considering residence relocation; and perceptions towards potential security measures to improve operational safety of flying cars. In addition, information relating to several dimensions of driving and travel behaviours and habits, and socio-demographic information of the participants were also collected. The dataset can be used as a baseline to design future surveys on Advanced Air Mobility (AAM) and flying cars, and to compare consumer perceptions across different regions and during different time periods.

Inhibition versus activation of canonical Wnt-signaling, to promote chondrogenic differentiation of Mesenchymal Stem Cells. A review.

Canonical Wnt signaling regulation is essential for controlling stemness and differentiation of mesenchymal stem cells (MSCs). However, the mechanism through which canonical Wnt-dependent MSC lineage commitment leads to chondrogenesis is controversial. Some studies hypothesize that inhibition of canonical Wnt signaling induces MSC chondrogenic differentiation, while others support that the pathway should be activated to achieve MSC chondrogenesis. The purpose of the present review is to analyze data from recent studies to elucidate parameters regarding the role of canonical Wnt signaling in MSC chondrogenic differentiation.

Karyotyping and Chromosomal Microarray Analysis in Women Requesting Amniocentesis for Isolated Sonographic Soft Markers or Advanced Maternal Age.

BACKGROUND: Chromosomal microarray analysis (CMA) has gained acceptance in prenatal diagnosis, gradually replacing the traditional cytogenetic analysis following amniocentesis or chorionic villi sampling due to its higher resolution than traditional cytogenetics. OBJCTIVE: The present study investigated the prevalence of major and sub-chromosomal abnormalities in fetuses with isolated ultrasound findings during routine anatomy scan or pregnancies of advanced maternal age after maternal request without medical indication. METHODS: Total number of 126 cases were included in total, consisted of two groups; the first group with isolated sonographic soft markers (84 fetuses) and the second group of advanced maternal age (42 fetuses). The group of isolated sonographic markers was further divided per anatomical system affected. The prevalence of genetic aberrations via QF-PCR and CMA was noted. RESULTS: Clinically significant genetic abnormalities were detected in 12% of the first and 7% of cases in the second group. Interestingly, 40% and 67% of abnormal cases in the first and second group respectively, were identified only after CMA, and they would have missed diagnosis with standard karyotype or QF-PCR alone. Most genetic aberrations were detected in fetuses with findings in the central nervous, craniofacial, cardiovascular, and musculoskeletal system. Sub-microscopic chromosomal aberrations identified only after CMA were gathered in cases with short long bones and in one case with ventriculomegaly. CONCLUSION: Even in pregnancies with a first trimester screening low risk result, the risk of identifying a clinically significant CMA aberration is considerable, when an isolated sonographic marker is identified later on in pregnancy or maternal age is advanced.

Do High Visibility Enforcement programs affect aggressive driving behavior? An empirical analysis using Naturalistic Driving Study data.

This paper investigates the effect of High Visibility Enforcement (HVE) programs on different types of aggressive driving behavior, namely, speeding, tailgating, unsafe lane changes and 'other' aggressive driving behavior types (occurrence of not-yielding right-of-way and red light or stop signs violations). For this purpose, the Second Strategic Highway Research Program (SHRP2) Naturalistic Driving Study (NDS) data are used, which include forward-facing videos and time series information with regard to trips conducted at or near the locations of HVE implementation. To capture the intensity and duration of speeding and tailgating, scaled metrics are developed. These metrics can capture varying levels of aggressive driving behavior enabling, thus, a direct comparison of the various behavioral aspects over time and among different drivers. To identify the effect of HVE and other trip, driver, vehicle or environmental factors on speeding and tailgating, while accounting for possible interrelationship among the behavior-specific scaled metrics, Seeming Unrelated Regression Equation (SURE) models were developed. To analyze the likelihood of occurrence of unsafe lane changes and 'other' aggressive driving behavior types, a grouped random parameters ordered probit model with heterogeneity in means and a correlated grouped random parameters binary logit model were estimated, respectively. The results showed that drivers' awareness of HVE implementation has the potential to decrease aggressive driving behavior patterns, especially unsafe lane changes and 'other' aggressive driving behaviors.

Analysis of stationary and dynamic factors affecting highway accident occurrence: A dynamic correlated grouped random parameters binary logit approach.

Traditional accident analysis typically explores non-time-varying (stationary) factors that affect accident occurrence on roadway segments. However, the impact of time-varying (dynamic) factors is not thoroughly investigated. This paper seeks to simultaneously identify pre-crash stationary and dynamic factors of accident occurrence, while accounting for unobserved heterogeneity. Using highly disaggregate information for the potential dynamic factors, and aggregate data for the traditional stationary elements, a dynamic binary random parameters (mixed) logit framework is employed. With this approach, the dynamic nature of weather-related, and driving- and pavement-condition information is jointly investigated with traditional roadway geometric and traffic characteristics. To additionally account for the combined effect of the dynamic and stationary factors on the accident occurrence, the developed random parameters logit framework allows for possible correlations among the random parameters. The analysis is based on crash and non-crash observations between 2011 and 2013, drawn from urban and rural highway segments in the state of Washington. The findings show that the proposed methodological framework can account for both stationary and dynamic factors affecting accident occurrence probabilities, for panel effects, for unobserved heterogeneity through the use of random parameters, and for possible correlation among the latter. The comparative evaluation among the correlated grouped random parameters, the uncorrelated random parameters logit models, and their fixed parameters logit counterpart, demonstrate the potential of the random parameters modeling, in general, and the benefits of the correlated grouped random parameters approach, specifically, in terms of statistical fit and explanatory power.

Intra-abdominal and intra-pelvic complications following operations around the hip: causes and management-a review of the literature.

Although successful and well-established procedures, hip operations whether elective or trauma are coupled with a variety of complications. Among the most uncommon complications are injuries to intra-abdominal or intra-pelvic organs which could prove potentially life-threatening. While there are various reports of such injuries in the literature, we aimed to perform a systematic review in order to examine the causes and relationships between intra-abdominal and intra-pelvic complications and the mechanism of injury, the pattern of presentation, identification, the course of management and outcomes. We identified 69 reports describing a total of 84 complications in intra-pelvic and intra-abdominal contents in 75 patients. These involved six major categories, including the intestinal tract, the urinary tract, the genital tract, the vascular system, the viscera and peripheral nerves. The most commonly injured system was the urinary (33.33%), followed by the vascular (29.76%) and the intestinal (22.62%). Among these systems, the most prevalent complications involved injury to the urinary bladder (32.14%), the large intestine (68.42%) and the external iliac artery (44%). The majority of recorded complications were postoperative with 71 incidents in 63 cases (84.52%). In intra-operative complications the most prevalent injury was due to hardware penetration (53.85%), while in postoperative it was due to hardware migration (92.06%). The management of injuries varied widely, with the most common approach being open exploration and direct repair (77.33%). The reported management outcomes included death (8%) and Girdlestone resection (2.67%), while the majority of the patients healed uneventfully (82.67%) owing mostly to immediate intervention. Despite being rare, such complications may still occur in a variety of settings and may subsequently lead to potential life-threatening situations. Thus, in order to avoid catastrophic outcomes we emphasize the need for prompt identification, immediate intervention and a multidisciplinary approach when necessary.

Posterior subdeltoid and external rotators preserving approach for reduction and fixation of displaced extra-articular fractures of the scapula.

BACKGROUND: Operative management of scapular body fractures, when indicated, typically involves extensive exposure through a posterior approach. We present our experience with a deltoid preserving approach that allows excellent exposure of the fracture lines for reduction and fixation while minimizing muscle detachment and overall tissue trauma. TECHNIQUE: Exposure of the scapula was obtained through a posterior incision. The posterior deltoid was exposed and retracted superiorly while the arm was abducted in accordance with Brodsky et al. The scapula was exposed in the interval between infraspinatus and teres minor. PATIENTS AND METHODS: Six patients were treated using this approach and were retrospectively reviewed. All were men with a mean age of 34 years (range 24-45 ± 6.7 years). The injuries involved two 14-A3.1 and four 14-A3.2 AO/OTA types of fractures. The mean follow-up after surgery was 28 months (range 21-36 ± 4.93 months). RESULTS: All fractures could be anatomically reduced and healed without compromise. The mean Constant score was 93.8 (range 91-97 ± 2.13), while range of motion and strength returned to levels equal to the uninjured shoulder. All patients returned to their previous level of activity. We did not observe atrophy of the posterior muscles or hardware complications, and none required hardware removal. CONCLUSION: The deltoid and external rotators preserving posterior approach permitted good visualization of the fractures while allowing reduction and fixation without extensive muscular dissection and provided excellent functional outcomes. We consider that it offers obvious advantages over more aggressive muscle detaching approaches. LEVEL OF EVIDENCE: Therapeutic study, IV.

Survivorship of a Porous Tantalum Monoblock Acetabular Component in Primary Hip Arthroplasty With a Mean Follow-Up of 18 Years.

BACKGROUND: The use of porous tantalum for the acetabular component in primary total hip arthroplasty (THA) has demonstrated excellent short-term and midterm results. However, long-term data are scarce. The purpose of this prospective study is to report the long-term clinical and radiologic outcome following use of an uncemented porous tantalum acetabular component in primary THA with a minimum follow-up of 17.5 years, in a previously studied cohort of patients. METHODS: We prospectively followed 128 consecutive primary THAs in 140 patients, between November 1997 and June 1999. A press-fit porous tantalum monoblock acetabular component was used in all cases. All patients were followed clinically and radiographically for a mean of 18.1 years (range, 17.5-19 years). RESULTS: Mean age of patients at the time of operation was 60.4 years. Harris hip score, Oxford hip score, and range of motion were dramatically improved in all cases (P < .001). At last follow-up, all cups were radiographically stable with no evidence of migration, gross polyethylene wear, progressive radiolucencies, osteolytic lesions, or acetabular fractures. The survivorship with reoperation for any reason as end point was 92.8% and the survivorship for aseptic loosening as an end point was 100%. CONCLUSION: The porous tantalum monoblock cup in primary THA demonstrated excellent clinical and radiographic outcomes with no failures because of aseptic loosening at a mean follow-up of 18.1 years.

Results from the surgical resection of severe heterotopic ossification of the hip: a case series of 26 patients.

INTRODUCTION: Surgical resection of heterotopic ossification (HO) around the hip joint is often challenging. The aim of this study is to evaluate the clinical and radiological outcomes following surgical resection of Brooker's type III and IV HO of the hip. METHODS: We retrospectively reviewed clinical and radiological data, between November 2006 and January 2013, of all patients who underwent surgical resection of severe HO of the hip. Brooker's grading, range of motion and the Harris Hip Score before and after surgery were recorded in all cases. The combined radiation (700 cGy preoperatively) and indomethacin regimen was used to prevent heterotopic ossification recurrence. RESULTS: Twenty-six patients (22 males and 4 females) were included in our study. Mean patient age was 47.38 years (range 24-72). The HO was graded as Brooker grade III in 3 patients (11.5%) and Brooker grade IV in 23 patients (88.5%). Mean time interval between HO development and resection was 40.8 months (range 13-156 months). All patients had CT scans prior to surgery. Mean follow-up was 31.4 months (range 24-40 months). There was no severe HO recurrence. Complications included one intraoperative injury of a femoral artery branch, one intraoperative femoral neck fracture treated with intramedullary nailing, one sciatic nerve injury and one superficial infection treated conservatively. CONCLUSIONS: Surgical resection of severe HO of the hip along with preoperative radiation and indomethacin provides excellent results; however, the complication rate is relatively high. Careful evaluation of the preoperative CT scan and wide exposure are required in order to identify all the involved neurovascular structures.

Latissimus Dorsi Transfer in Posterior Irreparable Rotator Cuff Tears.

BACKGROUND: Massive rotator cuff tears pose a difficult and complex challenge even for the experienced surgeon; inability to repair these tears by conventional means designates them as irreparable, while management becomes quite taxing. Several operative options have been suggested for the management of such lesions with varying degrees of success, while it is imperative to match patient demands and expectations to the predicted outcome. METHODS: Research articles are examined and key concepts are discussed, in order to provide an evidence based review of the available literature. The anatomy and pathomechanics along with the indications, contraindications and surgical techniques are reported. RESULTS: Transfer of the Latissimus dorsi has been used with success to restore shoulder function in deficits of the posterior rotator cuff. Although it can be used in a variety of settings, the ideal patient for a Latissimus dorsi tendon transfer is a young and active individual, with no glenohumeral osteoarthritis that has a severe disability and weakness related to an irreparable posterior cuff tear. CONCLUSION: Tendon transfers have proved to be a successful treatment option in salvaging this difficult problem, providing pain relief and restoring shoulder function. Despite the excellent functional outcomes and pain suppression following operation, a variety of factors may affect the outcome; thus making indications and preoperative assessment a valuable component.

A long term clinical outcome of the Medial Pivot Knee Arthroplasty System.

BACKGROUND: The ideal total knee arthroplasty (TKA) should provide maximum range of motion and functional stability for all desired daily activities and, if possible, to replicate normal knee kinematics and function. The ADVANCE® Medial Pivot (AMP) Knee System was designed with a highly congruent medial compartment and a less conforming lateral compartment to more closely mimic the kinematics of the normal knee and to offer more stability through out of range of motion (ROM). The purpose of this study was to evaluate the long-term clinical and radiographic outcomes of this TKA system. METHODS: Three hundred and twenty-five (325) patients (347 knees) with knee osteoarthritis underwent a TKA using the AMP prosthesis in our Department. For evaluation, objective and subjective clinical rating systems along with radiograph series were used. The average follow-up was 15.2years. RESULTS: All patients showed a statistically significant improvement (p<0.0005) in the Knee Society clinical rating system, Western Ontario and McMaster Universities Osteoarthritis Index questionnaire, SF-12® questionnaire, and Oxford knee score. The majority of patients (94%) were able to perform age-appropriate activities with a mean knee flexion of 120° (range, 105°-135°) at final follow-up. Survival analysis showed a cumulative success rate of 98.8% at 17years. CONCLUSION: The obtained results demonstrate excellent long-term clinical outcome for this knee design.

Surgical management of congenital torticollis in children older than 7 years with an average 10-year follow-up.

The aim of the present study is to present the results of the surgical management of late presenting cases of congenital muscular torticollis. Between 1990 and 2010, 31 cases of late presenting congenital muscular torticollis were managed surgically in our department. Postoperatively, head halter traction was applied for 10 days; a cervical brace was applied for 5 weeks, followed by a soft one collar for 3 months. The final result was assessed on the basis of the criteria of Cheng and Tang. In total, 84% of patients achieved an excellent final result and 16% of the patients achieved a good result. Our results indicated that in children older than 7 years, surgical release combined with appropriate orthosis and a structured physiotherapy regime can lead to satisfactory results.

Nerve injuries in total hip arthroplasty with a mini invasive anterior approach.

PURPOSE: Minimal invasive techniques in total hip arthroplasty (THA) have become increasingly popular during recent years. Despite much debate over the outcome of several minimal invasive techniques, complications arising from the use of anterior minimally invasive surgery (AMIS) for THA on a traction table are not well documented. Our study aims to focus on nerve damage during the AMIS procedure and the possible explanations of these injuries. METHODS: We reviewed all primary THAs performed with the AMIS technique using a traction table, over 5 years and recorded all intraoperative and postoperative complications up to the latest follow-up. We focused on nerve injuries and nerve function impairment following the aforementioned technique. RESULTS: Our study included 1,512 THAs performed with the AMIS technique in 2 major hip reconstruction centres (KAT General Hospital, Athens, Greece and University Hospital of Geneva, Switzerland), on 1,238 patients (985 women, 253 men; mean age 65.24 years). Mean follow-up was 29.4 months. We observed 51 cases of transient lateral femoral cutaneous nerve neuropraxia (3.37%), 4 cases of femoral nerve paralysis (3 permanent, 1 transient [0.26%]) and 1 case of permanent sciatic nerve paralysis (0.06%). No case of obturator or pudendal nerve injury was noticed. Mean age of these cases was 68.97 years. Sciatic and femoral nerve injuries were confirmed by electromyography, showing axonotmesis of the damaged nerve. CONCLUSIONS: Neurological injuries are a rare but distinct complication of THAs using the AMIS technique. Possible explanations for such referred nerve injuries are direct nerve injury, extreme traction, hyperextension, extreme external rotation of the leg, use of retractors and coexisting spinal deformities. Controlled use of traction in hip extension, cautious use of retractors and potential use of dynamometers may be useful, so that neurological damage can be avoided. Further studies are needed to fully elucidate the role of the above factors in AMIS neurological complications.

The necessity to restore the anatomic hip centre in congenital hip disease.

Total hip replacement (THR) is the treatment of choice for the patient suffering from end-stage hip osteoarthritis. In the presence of deformities due to congenital hip disease (CHD), THR is, in most of the cases, a difficult task, since the technique of performing such an operation is demanding and the results could vary. We present our experience and preferred strategies focusing on challenges and surgical techniques associated with reconstructing the dysplastic hip.

THA following deformities due to congenital dislocation of the hip joint.

Total hip replacement is the treatment of choice for the patient suffering from end-stage hip osteoarthritis. Excellent long-term results have been published. In the presence of deformities due to congenital hip dislocation, total hip replacement is, in most of the cases, a difficult task, since the technique of performing such an operation is demanding and the results could vary. This paper presents our experience and preferred strategies focusing on challenges and surgical techniques associated with reconstructing the dysplastic hip.

A two stage re-implantation protocol for the treatment of deep periprosthetic hip infection. Mid to long-term results.

Deep periprosthetic hip infection is a devastating complication. Goal of treatment is infection eradication and durable functional reconstruction. Two-stage re-implantation is the standard of treatment. From January 1998 to December 2004 we treated 38 patients with an infected THA. There were 24 females and 14 males, with a mean age of 67 years (61-75). The infection occurred 13 months to 15 years (mean: 7.2 years) after the index operation. The mean follow-up was 11.6 years (7 to 14). 35 patients were available for review. Almost one third of the patients had been treated before with antibiotics. In 5 cases more than one pathogen were present. In 3 cases, it was not possible to isolate a causative organism. In 15 cases (43%), a resistant pathogen was isolated. We used a two stage re- implantation protocol. Spacer was not used in any of the cases. Femoral revision was performed with uncemented implants, 21 of distal (wagner type) fixation and 14 of modular type with proximal fixation. 24 press fit shells (17 oTMT cups) and 11 Muller rings were used. In 33 cases (94%) eradication of infection was achieved. The mean HHS improved from a mean of 38.2 preoperatively to a mean of 88.6 at final follow-up (p<0.001). There was no case of implant loosening or migration. Chronic late infection can be managed successfully with a two stage re-implantation protocol, without interim spacer, including neglected cases, previous long term antibiotics and cases with resistant pathogens.

A study of factors affecting highway accident rates using the random-parameters tobit model.

A large body of previous literature has used a variety of count-data modeling techniques to study factors that affect the frequency of highway accidents over some time period on roadway segments of a specified length. An alternative approach to this problem views vehicle accident rates (accidents per mile driven) directly instead of their frequencies. Viewing the problem as continuous data instead of count data creates a problem in that roadway segments that do not have any observed accidents over the identified time period create continuous data that are left-censored at zero. Past research has appropriately applied a tobit regression model to address this censoring problem, but this research has been limited in accounting for unobserved heterogeneity because it has been assumed that the parameter estimates are fixed over roadway-segment observations. Using 9-year data from urban interstates in Indiana, this paper employs a random-parameters tobit regression to account for unobserved heterogeneity in the study of motor-vehicle accident rates. The empirical results show that the random-parameters tobit model outperforms its fixed-parameters counterpart and has the potential to provide a fuller understanding of the factors determining accident rates on specific roadway segments.

A multivariate tobit analysis of highway accident-injury-severity rates.

Relatively recent research has illustrated the potential that tobit regression has in studying factors that affect vehicle accident rates (accidents per distance traveled) on specific roadway segments. Tobit regression has been used because accident rates on specific roadway segments are continuous data that are left-censored at zero (they are censored because accidents may not be observed on all roadway segments during the period over which data are collected). This censoring may arise from a number of sources, one of which being the possibility that less severe crashes may be under-reported and thus may be less likely to appear in crash databases. Traditional tobit-regression analyses have dealt with the overall accident rate (all crashes regardless of injury severity), so the issue of censoring by the severity of crashes has not been addressed. However, a tobit-regression approach that considers accident rates by injury-severity level, such as the rate of no-injury, possible injury and injury accidents per distance traveled (as opposed to all accidents regardless of injury-severity), can potentially provide new insights, and address the possibility that censoring may vary by crash-injury severity. Using five-year data from highways in Washington State, this paper estimates a multivariate tobit model of accident-injury-severity rates that addresses the possibility of differential censoring across injury-severity levels, while also accounting for the possible contemporaneous error correlation resulting from commonly shared unobserved characteristics across roadway segments. The empirical results show that the multivariate tobit model outperforms its univariate counterpart, is practically equivalent to the multivariate negative binomial model, and has the potential to provide a fuller understanding of the factors determining accident-injury-severity rates on specific roadway segments.

An empirical assessment of fixed and random parameter logit models using crash- and non-crash-specific injury data.

Traditional crash-severity modeling uses detailed data gathered after a crash has occurred (number of vehicles involved, age of occupants, weather conditions at the time of the crash, types of vehicles involved, crash type, occupant restraint use, airbag deployment, etc.) to predict the level of occupant injury. However, for prediction purposes, the use of such detailed data makes assessing the impact of alternate safety countermeasures exceedingly difficult due to the large number of variables that need to be known. Using 5-year data from interstate highways in Indiana, this study explores fixed and random parameter statistical models using detailed crash-specific data and data that include the injury outcome of the crash but not other detailed crash-specific data (only more general data are used such as roadway geometrics, pavement condition and general weather and traffic characteristics). The analysis shows that, while models that do not use detailed crash-specific data do not perform as well as those that do, random parameter models using less detailed data still can provide a reasonable level of accuracy.

A note on modeling vehicle accident frequencies with random-parameters count models.

In recent years there have been numerous studies that have sought to understand the factors that determine the frequency of accidents on roadway segments over some period of time, using count data models and their variants (negative binomial and zero-inflated models). This study seeks to explore the use of random-parameters count models as another methodological alternative in analyzing accident frequencies. The empirical results show that random-parameters count models have the potential to provide a fuller understanding of the factors determining accident frequencies.