Investigation of Head Kinematics and Brain Strain Response During Soccer Heading Using a Custom-Fit Instrumented Mouthguard.

Association football, also known as soccer in some regions, is unique in encouraging its participants to intentionally use their head to gain a competitive advantage, including scoring a goal. Repetitive head impacts are now being increasingly linked to an inflated risk of developing long-term neurodegenerative disease. This study investigated the effect of heading passes from different distances, using head acceleration data and finite element modelling to estimate brain injury risk. Seven university-level participants wore a custom-fitted instrumented mouthguard to capture linear and angular acceleration-time data. They performed 10 headers within a laboratory environment, from a combination of short, medium, and long passes. Kinematic data was then used to calculate peak linear acceleration, peak angular velocity, and peak angular acceleration as well as two brain injury metrics: head injury criterion and rotational injury criterion. Six degrees of freedom acceleration-time data were also inputted into a widely accepted finite element brain model to estimate strain-response using mean peak strain and cumulative strain damage measure values. Five headers were considered to have a 25% concussion risk. Mean peak linear acceleration equalled 26 ± 7.9 g, mean peak angular velocity 7.20 ± 2.18 rad/s, mean peak angular acceleration 1730 ± 611 rad/s2, and 95th percentile mean peak strain 0.0962 ± 0.252. Some of these data were similar to brain injury metrics reported from American football, which supports the need for further investigation into soccer heading.

[Prevalence and Risk Factors of Chlamydia Trachomatis Infection Among Women Consulting at the Sexually Transmitted Infection Centre in la Reunion: A Cross-Sectional Study]. / Prévalence et Déterminants de L'infection à Chlamydia Trachomatis chez les Femmes Consultant en Centres de Dépistage à la Réunion: Une Étude Transversale.

Introduction: Chlamydia trachomatis (CT) infection is the commonest bacterial sexually transmitted infection (STI) in the world. Often asymptomatic, it can lead to significant complications in women. In France, since 2003, systematic screening for CT in STI center has been recommended for women aged less than 25 year. The main objective of this study was to determine CT prevalence in patients attending STI centers in Reunion Island. The second objective was to explore the determinants of this infection. Method: A cross-sectional survey using an anonymous questionnaire was conducted among women attending STI center in two hospitals in western and southern Reunion Island during one year. All women who had performed a CT PCR, based on vaginal self-swabs, were included. Results: Among the 620 patients tested, the prevalence of infection was 6.6% (95% CI [4.7-8.6]). By age group, the highest prevalence was between 12 and 17 years with 14.3% positive tests compared to 7.5% and 3.9% respectively in 18-24 and 25-67 year age group (p = 0.003). The risk factors for CT were a young age (p = 0.02), a first sexual intercourse between 11 and 14 years old (p = 0.01), lack of previous STI screening history (p = 0.02), and the following motives for seeking screening: "partner unfaithfulness" (p = 0.01) and "infected partner" (p = 0.02). Conclusion: This study highlights the high prevalence of CT among Reunionese minors. A more systematic screening and a reinforcement of STI awareness among young people in Reunion Island seem to be essential.

Risk factors associated with severe perineal tears: A five-year study.

OBJECTIVE: Our aim was to describe risk factors associated with 34DPT in operative and non-operative vaginal deliveries, over a five-year period. STUDY DESIGN: This was a retrospective cohort study including 39,227 vaginal deliveries from 2013 to 2017 in a single French University Hospital. Annual characteristics of the analyzed population were recorded. Univariate logistic regression was used to evaluate the association between these characteristics and 34DPT. Multivariate analysis was used to identify combinations of risk factors associated with instrumental delivery. RESULTS: The rate of perineal tears was constantly rising but rate of 34DPT was stable, ranging between 0.8 and 1.4% over the study period. Cesarean section rate was stable between 18.8% and 19.6%. Rate of diabetes, preeclampsia and obesity (BMI < 40) was increasing and episiotomy rate decreasing (from 19.8% to 11.8%). Operative deliveries rate remained stable between 11 and 12.8%. Multivariate regression showed that gestational age over 39 weeks (aOR 1.18, 95% CI [1.02; 1.35]), birth weight over 3500 g (aOR 1.62, 95% CI [1.05; 2.49]) were associated with 34DPT in patients without operative vaginal deliveries but not episiotomy. Gestational age (aOR 1.71, 95% CI [1.18; 2.47]), episiotomy (aOR 0.55, 95% CI [0.38; 0.79]) and diabetes (aOR 1.73, 95% CI [1.15; 2.61]) were associated with 34DPT among patients with operative vaginal deliveries. CONCLUSION: In a tertiary medical center model with low cesarean section rate, factors associated with 34DPT were different among patients with or without operative vaginal delivery. The question of the protective effect of mediolateral episiotomy against 34DPT in case of operative delivery deserves further investigations.

An in-vitro animal bone model study to predict spiral fracture strength of long bones in the young infant.

INTRODUCTION: The risk of fracture from a non-accidental injury is highest in the infant age group. A spiral fracture of the long bone can occur equally from accidental and non-accidental causes, meaning the clinical judgement of non-accidental injury in an infant is particularly challenging. This study aimed to assist in differentiating accidental, from non-accidental, injury in infants, by establishing whether correlation exists between geometry and torsional strength in the immature long bone. METHODS: Immature porcine third and fourth metacarpals (n = 21) were imaged with a dual energy x-ray absorptiometry (DEXA) scanner to measure their linear bone mineral content (BMCL), bone mineral density (BMD) and section modulus (Z). The specimens were then subjected to a torque of one degree per second until failure. The failure strength and the three DEXA measures were analyzed for a correlation. RESULTS: The mean failure strength of 11 successful tests was 13.71Nm (+/-SD 2.42Nm), with correlation to BMCL, BMD and Z described by r2 = 0.81, 0.283 and 0.75 respectively. CONCLUSION: This study is a novel attempt at estimating torsional strength of long bones in a specific paediatric age group using a size-matched animal bone model. It found a strong correlation between bone and fracture strength parameters over the BMCL range of 0.59-0.77 g/cm.

Development and validation of a physical model to investigate the biomechanics of infant head impact.

Head injury in childhood is the single most common cause of death or permanent disability from injury. However, despite its frequency and significance, there is little understanding of the response of a child's head to injurious loading. This is a significant limitation when making early diagnoses, informing clinical and/or forensic management or injury prevention strategies. With respect to impact vulnerability, current understanding is predominantly based on a few post-mortem-human-surrogate (PMHS) experiments. Researchers, out of experimental necessity, typically derive acceleration data, currently an established measure for head impact vulnerability, by calculation. Impact force is divided by the head mass, to produce a "global approximation", a single-generalised head response acceleration value. A need exists for a new experimental methodology, which can provide specific regional or localised response data. A surrogate infant head, was created from high resolution computer tomography scans with properties closely matched to tissue response data and validated against PMHS head impact acceleration data. The skull was 3D-printed from co-polymer materials. The brain, represented as a lumped mass, comprised of an injected gelatin/water mix. High-Speed Digital-Image-Correlation optically measured linear and angular velocities and accelerations, strains and strain rates. The "global approximation" was challenged by comparison with regional and local acceleration data. During impacts, perpendicular (at 90°) to a surface, regional and local accelerations were up to three times greater than the concomitant "global" accelerations. Differential acceleration patterns were very sensitive to impact location. Suture and fontanelle regions demonstrated ten times more strain (103%/s) than bone, resulting in skull deformations similar in magnitude to those observed during child birth, but at much higher rates. Surprisingly, perpendicular impacts produced significantly greater rotational velocities and accelerations, which are closer to current published injury thresholds than expected, seemingly as a result of deformational changes to the complex skull geometry. The methodology has proven a significant new step in characterising and understanding infant head injury mechanics.

Fertility after surgery for deep infiltrating endometriosis.

OBJECTIVES: The population of Reunion Island has a high prevalence of endometriosis impacting fertility. The aim of this series is to assess the fertility of women undergoing surgical approach of deep infiltrating endometriosis and to study the characteristics of the pregnancy outcomes. MATERIAL AND METHODS: This is a retrospective 2 centers study, including all women wanting to be pregnant and operated for deep endometriosis in any of the 2 hospitals of the CHU of Reunion Island between January 2012 and May 2013. RESULTS: Sixty-three women were included. Twenty-four (38%) had more than one operation and 16 (25.4%) experienced one or more complications. Fifty-eight (92%) had complete resection of the endometriosis. Twenty-seven (42.9%) women became pregnant at least once, spontaneously in 44.4%. Average delay for first pregnancy was 14.2 months. Twenty-two (34.9%) women became pregnant before 24 months. Among the 34 pregnancies, 20 ended with a live newborn. Premature delivery rate was 35%, cesarean section rate 10% and average birth weight was at 45th percentile. CONCLUSION: Fertility remains good after surgery for deep infiltrating endometriosis but the delay between operation and pregnancy is increased when a surgical complication occurs. Premature delivery rate is high. No pregnancy occurred in case of incomplete resection or after age of 36.

Vein grafts to augment flexor tendon repairs: a biomechanical study on strength and gap resistance.

The ultimate tensile repair strength and gap formation of the pig extensor tendons repaired with a standard 4-strand Savage with epitendinous suture repair, was compared with a new technique of adding a vein sleeve. Force and displacement data were recorded, and video images during linear cyclic loading up to failure. At 35 N, video-graphic observation detected significantly smaller gap lengths in the standard and vein repair specimens compared with standard repair specimens (p = 0.047). The incidence of 3 mm gaps between the repaired tendon ends in the standard repair group was 20 %, but no 3 mm gaps were seen in the standard and vein specimens. The addition of a vein sleeve increased the ultimate tensile strength of the standard repair from 50.4 N (4.5) to 55.4 N (4.5); this was statistically significant (p = 0.03). This study demonstrated that the addition of a vein graft prevented gap formation and increased ultimate tensile strength of tendon repair.

The potential effects of floor impact surfaces on infant head injury outcome during a short fall.

When considering cases of infant head injury as a result of a short fall, investigators often have to base their opinions on the potential severity of a head injury on a scene description and/or photographic evidence of the potential impact surfaces. While variation in the attenuation properties of typical domestic surfaces and underlying support structures have been reported in the literature, this study investigates whether there is a need to consider the nature and composition of specific potential impact floor surfaces/sites, within a scene, prior to providing an opinion about the likely head impact injury outcome. An instrumented headform was impacted within a suspected crime scene to determine whether different potential impact sites posed different risks of producing head injury. The impact acceleration-time waveform, for the headform, was shown to vary considerably across the floor. By applying recognized head impact injury risk measures (peak g and head injury criterion), it was illustrated that the risk of an infant sustaining a significant head injury could vary considerably, depending upon the exact point of impact with the floor. This study highlights the potential for variation in impact force across a scene and illustrates the need to consider surface composition at specific sites across the entire potential impact area, since the risk of head injury can vary significantly. Caution should therefore be exercised when expressing opinions based solely on verbal, written or photographic evidence of head impact surfaces, without due consideration of the specific area onto which a head might have impacted.

The bio-tribological characteristics of synthetic tissue grafts.

The use of synthetic connective tissue grafts became popular in the mid-1980s, particularly for anterior cruciate ligament reconstruction; however, this trend was soon changed given the high failure rate due to abrasive wear. More than 20 years later, a vast range of grafts are available to the orthopaedic surgeon for augmenting connective tissue following rupture or tissue loss. While the biomechanical properties of these synthetic grafts become ever closer to the natural tissue, there have been no reports of their bio-tribological (i.e. bio-friction) characteristics. In this study, the bio-tribological performance of three clinically available synthetic tissue grafts, and natural tendon, was investigated. It was established that the natural tissue exhibits fluid-film lubrication characteristics and hence is highly efficient when sliding against opposing tissues. Conversely, all the synthetic tissues demonstrated boundary or mixed lubrication regimes, resulting in surface-surface contact, which will subsequently cause third body wear. The tribological performance of the synthetic tissue, however, appeared to be dependent on the macroscopic structure. This study indicates that there is a need for synthetic tissue designs to have improved frictional characteristics or to use a scaffold structure that encourages tissue in-growth. Such a development would optimize the bio-tribological properties of the synthetic tissue and thereby maximize longevity.

[Ogilvie's syndrome following cesarean section: Just think! Report of two cases and review of the literature]. / Syndrome d'Ogilvie après césarienne : savoir y penser ! À propos de deux cas post-césarienne et revue de la littérature.

OBJECTIVES: To identify clinical and radiological signs of the post-cesarean Ogilvie's syndrome in order to establish the appropriate treatment. PATIENTS AND METHODS: Based on the Medline research, we listed 41 cases of Ogilvie's syndrome after cesarean section. We analyzed the patient's age, the clinical and radiological signs, the time to diagnosis, and the treatments and their efficiency. RESULTS: The clinical signs generally appear in the first 72 h after cesarean. Diagnosis of Ogilvie's syndrome is based on a clinical picture of acute obstruction of the large bowel and by X-ray showing a large caecum without pathological lesion. If the caecal diameter is under 12 cm, conservative treatment is done with colonoscopic decompression when necessary, however if there are signs of peritonitis surgery is recommended. CONCLUSION: Ogilvie's syndrome after cesarean section is uncommon. Diagnosis must be fast in order to avoid the caecum to burst causing faecal peritonitis, which carries slight mortality rate.

Medical engineering at Cardiff University. Part 1: Undergraduate programmes of study.

Cardiff University has offered a medical engineering undergraduate programme since 2001 and hence delivers one of the longest-running and most established medical engineering programmes within the UK. It currently offers BEng (Hons) and MEng (Hons) programmes that are both accredited by the Institution of Mechanical Engineers and include the option to undertake a year in industrial employment. The admissions policy ensures that the intake consists of a diverse range of students and is typically very successful in attracting female students. The programmes consist of six key academic threads which ensure that the content is both relevant and continuous, with all threads tailored to provide a patient-focused learning environment. Students initially learn core and fundamental principles in years 1 and 2, supported by a range of laboratories and practical experimentation. The latter years then encourage the students to corroborate and apply this knowledge, including involvement in a range of project-based learning exercises. The programme is delivered by a core of experienced academic medical engineers, with support from other engineering colleagues, as well as colleagues from the School of Biosciences, the School of Medicine, and the National Health Service. Thus, the programme delivers a wide range of modules which guarantee that graduating students have a thorough understanding of all possible career options. These two factors are significant in making it possible for students to follow their chosen career path upon graduation.

Medical engineering at Cardiff University. Part 2: Postgraduate programmes of study.

The Medical Engineering team within the School of Engineering, Cardiff University, delivers two postgraduate programmes of study. Established over 10 years ago, the part-time MSc programmes in Orthopaedic Engineering and Clinical Engineering offer the opportunity of further study while remaining within full-time employment. Both programmes deliver 120 taught credits over two academic years via a series of residential weekends, with successful completion enabling the student to undertake and then defend a 60-credit research dissertation. Fulfilling a specific role on the career pathway for both student cohorts, the strength of each programme is indicated by the consistent number of applicants.

Optical calibration for both out-of-plane and in-plane displacement sensitivity of acoustic emission sensors.

The use of piezoelectric sensors for acoustic emission (AE) monitoring provides an extremely sensitive detection method of AE events. The sensors are used to detect the stress waves, resulting from an AE event, which arrive at the surface of a structure. The sensors provide high sensitivity, and are generally based on a high-Q design where the sensor is used to detect AE events around its resonance. Sensitivity calibration of these sensors is essential for accurate assessment of the AE measurement and particularly important for sensors mounted on safety critical structures. This paper proposes an optical method which enables both the out-of-plane and in-plane displacement sensitivity of an AE sensor to be established independently from each other. In the method, a laser homodyne interferometer is used to measure the out-of-plane and in-plane displacement of the surface of a large test block excited by a repeatable source transducer. The out-of-plane displacement is measured by aligning the laser beam perpendicular to the surface with time gating of the receive waveform used to isolate only the direct arrival of the longitudinal wave produced by the piston source transducer. For the in-plane displacement measurement, the laser beam is aligned parallel to the surface to intersect a small optically reflective step with the time waveform being gated to measure only the direct shear arrival produced using a normal incidence shear wave source transducer. In each case, the interferometer measurement is followed by coupling the sensor under test to the measurement surface, which is then exposed to the same acoustic field and the sensor output signal measured. This substitution method allows the sensor sensitivity to be obtained in terms of volts per unit displacement for both the out-of-plane and the in-plane surface displacement. The method provides a comprehensive description of an AE sensor response to different planes of displacement and offers the potential for a traceable sensor calibration to units of length.

Utilization of carbon nanofibers for airborne ultrasonic acoustic field detection using heterodyne interferometry.

Carbon nanofibers and nanotubes are currently being utilized as active elements in acoustic sensors for emerging microelectromechanical systems and nanoelectromechanical systems technologies. A methodology for measuring the displacement of carbon nanofibers in combination with heterodyne interferometry is reported here. Experimental results show that ultrasonic field detection is possible using this technique, and results are presented for measurements in the ultrasonic frequency range. This approach could potentially lead to new calibration methods for ultrasonic sensors. A different approach to that of interferometry is also reported for future investigation.

[Posterior IVS: feasibility and preliminary results in a continuous series of 108 cases]. / Colpopexie infracoccygéale translévatorienne postérieure (IVS): faisabilité et premiers résultats d'une série continue de 108 cas.

OBJECTIVE: We present a continuous series of 108 patients operated for genital prolapse by vaginal route using the Posterior Intravaginal Slingplasty (PIVS) technique (IVS 02 Tyco Healthcare, polypropylene multifilament band), associated to prosthetic repair of cystocele and/or rectocele if present by interposition of a mesh (Surgipro Mesh Tyco Healthcare). PATIENTS AND METHODS: Inclusion criteria were C and/or D point superior to -1 cm. The main criterion is the assessment of feasibility, morbidity and anatomical results obtained for the treatment of level 1 genital prolapse with an average follow-up of 19 months. The secondary criterion is to assess the same elements for the treatment of associated cystocele and rectocele. RESULTS: Seventy-three patients presented with a cystocele (Ba>-1 cm) and eighty-seven with a rectocele (Bp>-1 cm). Nineteen patients had a hysterectomy, twenty had amputation of the cervix and forty-nine were treated for stress urinary incontinence by anterior IVS. Perioperative complications consisted of seven bladder injuries, one injury to the lower rectum during dissection. Postoperative complications were: a loss more than 2 g haemoglobin for seven patients, two haematomas in the cave of Retzius, one haematoma of the pararectal fossa with secondary superinfection requiring mesh removal. Three erosions occurred: two in front of the vesicovaginal prosthesis and one in front of the recto-vaginal prosthesis. The latter became secondarily super infected and had to be removed. With regard to the anatomical result, one failure was noted for the Posterior IVS excluding the two patients in whom the prosthetic material had to be removed. For the anterior compartment, eight failures occurred. From a functional perspective, we noted one case of dyspareunia due to fibrous retraction and seven patients complained of de novo stress urinary incontinence and eight of moderate voiding obstruction. DISCUSSION AND CONCLUSIONS: The technical feasibility is excellent. Feasibility of level 2 repair, anterior or posterior, but results on cystocele are insufficient in case of lateral defect.

Lubrication regime of the contact between fat and bone in bovine tissue.

Fat pads are masses of encapsulated adipose tissue located throughout the human body. Whilst a number of studies describe these soft tissues anatomically little is known about their biomechanics, and surgeons may excise them arthroscopically if they hinder visual inspection of the joint or bursa. By measuring the coefficient of friction between, and performing Sommerfeld analysis of, the surfaces approximating the in vivo conjuncture, this contact has been shown to have a coefficient of friction of the order of 0.01. The system appears to be lubricated hydrodynamically, thus possibly promoting low levels of wear. It is suggested that one of the functions of fat pads associated with subtendinous bursae and synovial joints is to generate a hydrodynamic lubricating layer between the opposing surfaces.

[Surgical treatment for female stress urinary incontinence by transobturator tape (outside in). Study of 70 cases]. / Cure chirurgicale de l'incontinence urinaire d'effort de la femme par bandelette transobturatrice (de dehors en dedans). Etude de 70 cas.

OBJECTIVES: To evaluate the feasibility, the efficacy and the innocuousness of suburethral transobturator support using multifilament polypropylene transobturator tape (TOT) inside out for stress urinary incontinence in women. MATERIALS AND METHODS: The study concerns 70 patients representing our team's first experience of this technique. The inclusion criterion was persistent SUI despite perineal rehabilitation. There were no exclusion criteria. Among the 70 patients, 22 (31%) presented with associated genital prolapse. Mean parity was 2.6 (extremes ranging from 0 to 6). Thirty-five patients were menopaused (50%), of whom 12 (34%) were under hormone replacement therapy. We retained five judgement criteria to evaluate this surgical act: duration of surgery and hospitalisation, per- and postoperative complications and functional results on SUI (via a telephone questionnaire). RESULTS: The rate of positive results (healing or improvement) was 84% with a mean follow-up of 14.5 months. The rate of peroperative complications was very low: 1.4% (only one case of bladder injury). The mean duration of surgery was 23 minutes. The mean duration of hospitalisation in the case of isolated TOT was 1.25 days. CONCLUSION: The transobturator approach is a feasible, safe and efficient short-term surgical technique. Results inferior to those observed in the literature are probably due to the learning curve in a university hospital unit. None of the preoperative data (age, parity, body mass index, history of SUI treatment or hysterectomy, hormonal status, associated prolapse, mean urethral closure pressure, clinical vesical hyperactivity syndrome) appears to influence results; however, the study strength is poor due to the small study population.

[Laparoscopic management of pelvic mass in pregnancy]. / Prise en charge coelioscopique des masses latéro-utérines pendant la grossesse.

OBJECTIVES: To determine the feasibility, safety and limiting factors of laparoscopic management of pelvic mass in pregnancy. MATERIAL: and methods. During a 10-year period, 21 laparoscopic procedures were performed in patients with pelvic masses in pregnancy after exclusion of appendicitis and ectopic pregnancy. Laparoscopic surgery was done during the first trimester of pregnancy in 8 cases, the second trimester in 12 cases and the third trimester in one case. All the procedures were performed with general anesthesia and the laparoscopic cystectomies were performed with the intraperitoneal technique. RESULTS: The indications were: persistent or sonographically abnormal ovarian cyst (12 cases), torsion of ovarian cyst (5 cases), and symptomatic pelvic mass (4 cases: 2 painful cysts and 2 infarction of fibroma). One borderline tumor were discovered. The laparoscopic procedure could not be performed in two cases due to difficulty of access to the lesion. No patient encountered complications during the intra- and post-operative periods. The mean hospital stay was 4.5 days. The outcome of the pregnancy was normal in all cases. CONCLUSION: Laparoscopic management of pelvic masses in pregnancy by an experienced team, is a safe and effective procedure.