Three-dimensional reconstruction of the upper limb from anatomical slices of the Korean visible human: simulation and educational application.

PURPOSE: Digital anatomy is a novel emerging discipline. Use of virtual reality brings a revolution in educational anatomy by improving retention and learning outcomes. Indeed, virtual dissection is a new learning tool for students and surgeons. Three-dimensional vectorial models of the human body can be created from anatomical slices obtained by lengthy series of cryosection from the visible human projects. The aim of this paper is to show how these mesh models could be embedded into an Acrobat® 3dpdf interface, to produce an easy-to-use fully interactive educational tool. METHODS: The learning of this method and its practical application were evaluated on a multicentric cohort of 86 people divided into 3 groups, according to the duration of their training (1, 2 or 3 days, respectively). Participants learned how to use the Mesh tool and how to model 3D structures from anatomical sections. At the end of the training, they were given a survey form. Participants were also asked to rate the training (Poor; Average; Good; Very Good; Excellent). RESULTS: Ninety four percent of the subjects rated the device as excellent and would continue to use digital anatomy in their practice. CONCLUSION: This result is the Diva3d® virtual dissection table, a powerful educational tool for anatomists and students. It could also be the basis of future simulation tools for hand surgeons training.

The transverse facial artery and the mandibular condylar process: An anatomic and radiologic study.

INTRODUCTION: In surgical approaches to condylar fractures, there is a risk of damage to the transverse facial artery (TFA) which may in turn account for impaired blood supply to the temporomandibular joint (TMJ). In order to investigate the risk of damage to the TFA, and prevent lesions to this artery resulting from TMJ surgical procedures, we studied the distance between the TFA and the head of the condylar process. METHODOLOGY: A dissection study was conducted on 10 fresh cadavers (20 condylar specimens dissected), involving fifty CT scans of the face with intravenous contrast. Vertical distance from the TFA to the top of the mandibular condyle head and distance from the TFA to the lateral aspect of the mandibular condyle were measured. RESULTS: The lateral aspect of the mandibular condyle is vascularized by branches emanating from the superficial temporal artery (STA) and the TFA. The TFA was located 1.84 ± 0.6 cm below the condylar process of the mandible and ran 1.09 ± 0.54 mm lateral to the head of the mandibular condyle. DISCUSSION: In order to spare the TFA in fractures involving the condylar neck, surgical approaches to the condyle should preserve the uppermost 2 cm of the lateral surface of the condyle during dissection. Due to the necessity for periosteal elevation of the lateral surface of the condyle in condylar head fractures, it is possible to spare the TFA, running lateral to the condylar neck, and the medial condylar surface in order to leave the branches that derive from the maxillary artery (MA) intact.

Avalanche statistics from data with low time resolution.

Extracting avalanche distributions from experimental microplasticity data can be hampered by limited time resolution. We compute the effects of low time resolution on avalanche size distributions and give quantitative criteria for diagnosing and circumventing problems associated with low time resolution. We show that traditional analysis of data obtained at low acquisition rates can lead to avalanche size distributions with incorrect power-law exponents or no power-law scaling at all. Furthermore, we demonstrate that it can lead to apparent data collapses with incorrect power-law and cutoff exponents. We propose new methods to analyze low-resolution stress-time series that can recover the size distribution of the underlying avalanches even when the resolution is so low that naive analysis methods give incorrect results. We test these methods on both downsampled simulation data from a simple model and downsampled bulk metallic glass compression data and find that the methods recover the correct critical exponents.

[3D modeling of the female pelvis by Computer-Assisted Anatomical Dissection: Applications and perspectives]. / Modélisation anatomique 3D du pelvis féminin par dissection anatomique assistée par ordinateur : applications et perspectives.

OBJECTIVES: To achieve a 3D vectorial model of a female pelvis by Computer-Assisted Anatomical Dissection and to assess educationnal and surgical applications. MATERIALS AND METHOD: From the database of "visible female" of Visible Human Project(®) (VHP) of the "national library of medicine" NLM (United States), we used 739 transverse anatomical slices of 0.33mm thickness going from L4 to the trochanters. The manual segmentation of each anatomical structures was done with Winsurf(®) software version 4.3. Each anatomical element was built as a separate vectorial object. The whole colored-rendered vectorial model with realistic textures was exported in 3Dpdf format to allow a real time interactive manipulation with Acrobat(®) pro version 11 software. RESULTS: Each element can be handled separately at any transparency, which allows an anatomical learning by systems: skeleton, pelvic organs, urogenital system, arterial and venous vascularization. This 3D anatomical model can be used as data bank to teach of the fundamental anatomy. CONCLUSION: This 3D vectorial model, realistic and interactive constitutes an efficient educational tool for the teaching of the anatomy of the pelvis. 3D printing of the pelvis is possible with the new printers.

Universality of slip avalanches in flowing granular matter.

The search for scale-bridging relations in the deformation of amorphous materials presents a current challenge with tremendous applications in material science, engineering and geology. While generic features in the flow and microscopic dynamics support the idea of a universal scaling theory of deformation, direct microscopic evidence remains poor. Here, we provide the first measurement of internal scaling relations in the deformation of granular matter. By combining macroscopic force fluctuation measurements with internal strain imaging, we demonstrate the existence of robust scaling relations from particle-scale to macroscopic flow. We identify consistent power-law relations truncated by systematic pressure-dependent cutoff, in agreement with recent mean-field theory of slip avalanches in elasto-plastic materials, revealing the existence of a mechanical critical point. These results experimentally establish scale-bridging relations in the flow of matter, paving the way to a new universal theory of deformation.

Effect of compression stockings on cutaneous microcirculation: Evaluation based on measurements of the skin thermal conductivity.

OBJECTIVE: To study of the microcirculatory effects of elastic compression stockings. MATERIALS AND METHODS: In phlebology, laser Doppler techniques (flux or imaging) are widely used to investigate cutaneous microcirculation. It is a method used to explore microcirculation by detecting blood flow in skin capillaries. Flux and imaging instruments evaluate, non-invasively in real-time, the perfusion of cutaneous micro vessels. Such tools, well known by the vascular community, are not really suitable to our protocol which requires evaluation through the elastic compression stockings fabric. Therefore, we involve another instrument, called the Hematron (developed by Insa-Lyon, Biomedical Sensor Group, Nanotechnologies Institute of Lyon), to investigate the relationship between skin microcirculatory activities and external compression provided by elastic compression stockings. The Hematron measurement principle is based on the monitoring of the skin's thermal conductivity. This clinical study examined a group of 30 female subjects, aged 42 years ±2 years, who suffer from minor symptoms of chronic venous disease, classified as C0s, and C1s (CEAP). RESULTS: The resulting figures show, subsequent to the pressure exerted by elastic compression stockings, an improvement of microcirculatory activities observed in 83% of the subjects, and a decreased effect was detected in the remaining 17%. Among the total population, the global average increase of the skin's microcirculatory activities is evaluated at 7.63% ± 1.80% (p < 0.0001). CONCLUSION: The results from this study show that the pressure effects of elastic compression stockings has a direct influence on the skin's microcirculation within this female sample group having minor chronic venous insufficiency signs. Further investigations are required for a deeper understanding of the elastic compression stockings effects on the microcirculatory activity in venous diseases at other stages of pathology.

Carboplatin versus alternating carboplatin and doxorubicin for the adjuvant treatment of canine appendicular osteosarcoma: a randomized, phase III trial.

Despite numerous published studies describing adjuvant chemotherapy for canine appendicular osteosarcoma, there is no consensus as to the optimal chemotherapy protocol. The purpose of this study was to determine whether either of two protocols would be associated with longer disease-free interval (DFI) in dogs with appendicular osteosarcoma following amputation. Dogs with histologically confirmed appendicular osteosarcoma that were free of gross metastases and underwent amputation were eligible for enrollment. Dogs were randomized to receive either six doses of carboplatin or three doses each of carboplatin and doxorubicin on an alternating schedule. Fifty dogs were included. Dogs receiving carboplatin alone had a significantly longer DFI (425 versus 135 days) than dogs receiving alternating carboplatin and doxorubicin (P = 0.04). Toxicity was similar between groups. These results suggest that six doses of carboplatin may be associated superior DFI when compared to six total doses of carboplatin and doxorubicin.

Slip statistics of dislocation avalanches under different loading modes.

Slowly compressed microcrystals deform via intermittent slip events, observed as displacement jumps or stress drops. Experiments often use one of two loading modes: an increasing applied stress (stress driven, soft), or a constant strain rate (strain driven, hard). In this work we experimentally test the influence of the deformation loading conditions on the scaling behavior of slip events. It is found that these common deformation modes strongly affect time series properties, but not the scaling behavior of the slip statistics when analyzed with a mean-field model. With increasing plastic strain, the slip events are found to be smaller and more frequent when strain driven, and the slip-size distributions obtained for both drives collapse onto the same scaling function with the same exponents. The experimental results agree with the predictions of the used mean-field model, linking the slip behavior under different loading modes.

Anatomy of the Hunter's canal and its role in the venous outlet syndrome of the lower limb.

BACKGROUND: The "Adductor canal syndrome" has been described as an unusual cause of acute arterial occlusion inside the Hunter's canal in young sportsmen. It may also produce a compressive neuropathy of the saphenous nerve. To our knowledge, femoral vein compression in the canal has never been reported. OBJECTIVE: To describe the anatomy, to propose a physiology of this canal, and to show that the femoral vein is much more exposed than the artery to compression inside this adductor hiatus, particularly at the outlet. MATERIAL AND METHODS: The whole adductor canal was exposed in 100 limbs for anatomical study following latex injection. A series of 200 phlebographies and 100 CT venograms were also analyzed. RESULTS: Anatomically, we found a musculotendinous band called the "vastoadductor membrane," which jointed the adductor tendon to the vastus medialis in all the cases. The femoral vein, located more posteriorly, was frequently narrowed at this level. This band can create a notch with a venous stenosis at the outlet of the Hunter's canal, usually located 12-14 cm above the femoral condyle. Two femoral valves constitute the landmark of the canal on the venograms: the lower is just below the outlet, 9 cm above the condyle. The second valve is 3 cm higher inside the canal.Functionally, the cadaveric simulations showed that the contraction of the adductor longus closes the hiatus, while the adductor magnus opens it. Our hypothesis is that Hunter's canal prevents femoropopliteal axis reflux by synchronizing with calf pump ejection during ambulation. CONCLUSION: Compression of the femoral vein inside the adductor's canal is an underestimated and misdiagnosed cause of postural stenosis of the femoral vein. Ultrasound investigation of both limbs in patients with chronic venous disease (CVD) should be systematically carried out at this precise level in order to prevent future occlusion and onset of acute deep vein thrombosis.

Relationship between medical compression and intramuscular pressure as an explanation of a compression paradox.

BACKGROUND: Using standing magnetic resonance imaging (MRI), we recently showed that medical compression, providing an interface pressure (IP) of 22 mmHg, significantly compressed the deep veins of the leg but not, paradoxically, superficial varicose veins. OBJECTIVE: To provide an explanation for this compression paradox by studying the correlation between the IP exerted by medical compression and intramuscular pressure (IMP). MATERIAL AND METHODS: In 10 legs of five healthy subjects, we studied the effects of different IPs on the IMP of the medial gastrocnemius muscle. The IP produced by a cuff manometer was verified by a Picopress® device. The IMP was measured with a 21G needle connected to a manometer. Pressure data were recorded in the prone and standing positions with cuff manometer pressures from 0 to 50 mmHg. RESULTS: In the prone position, an IP of less than 20 did not significantly change the IMP. On the contrary, a perfect linear correlation with the IMP (r = 0.99) was observed with an IP from 20 to 50 mmHg. We found the same correlation in the standing position. CONCLUSION: We found that an IP of 22 mmHg produced a significant IMP increase from 32 to 54 mmHg, in the standing position. At the same time, the subcutaneous pressure is only provided by the compression device, on healthy subjects. In other words, the subcutaneous pressure plus the IP is only a little higher than 22 mmHg-a pressure which is too low to reduce the caliber of the superficial veins. This is in accordance with our standing MRI 3D anatomical study which showed that, paradoxically, when applying low pressures (IP), the deep veins are compressed while the superficial veins are not.

Three-dimensional reconstruction of the lower limb's venous system in human fetuses using the computer-assisted anatomical dissection (CAAD) technique.

OBJECTIVE: The aim of the present study was to show the feasibility and describe the first results of a 3D reconstruction of the venous network of the lower limbs in human fetus using the computer-assisted anatomical dissection (CAAD) technique. MATERIALS AND METHODS: We used limbs from two human fetuses, respectively, 14 and 15 weeks gestation old. Specimens were fixed in 10% formalin, embedded in paraffin wax and serially sectioned at 10 m. The histological slices were stained using HES and Masson Trichrome for soft tissues identification. Immunolabeling techniques using the Protein S-100 marker and the D2-40 marker were used to identify nerves and vessels, respectively. Stained slices were aligned manually, labeled and digitalized. The segmentation of all anatomical structures was achieved using the WinSurf(®) software after manual drawing. RESULTS: A 3D interactive vectorial model of the whole leg, including skin, bone, muscles, arteries, veins, and nerves was obtained. In all limbs, we observed the presence of a big axial vein traveling along the sciatic nerve. In addition, the femoral vein appeared as a small plexus. Although this is a common anatomical feature at the end of organogenesis, this feature is observed in only 9% of adults. Usually interpreted as an "anatomical variation of the femoral vein" it should be considered as a light truncular malformation. These observations bring further support to our proposed "angio-guiding nerves" hypothesis. CONCLUSION: This preliminary study shows that the CAAD technique provided an accurate 3D reconstruction of the fetal leg veins anatomy. It should bring a new insight for the understanding of the different steps of development of the human venous system.

Inhibition controls for qualitative real-time PCR assays: are they necessary for all specimen matrices?

A retrospective analysis of 386,706 specimens representing a variety of matrix types used in qualitative real-time PCR assays determined the overall inhibition rate to be 0.87% when the inhibition control was added preextraction to 5,613 specimens and 0.01% when the inhibition control was added postextraction but preamplification in 381,093 specimens. Inhibition rates of ≤ 1% were found for all specimen matrix types except urine and formalin-fixed, paraffin-embedded tissue.

[Computerized three-dimensional reconstruction of the retrohepatic segment of inferior vena cava of a 20 mm human embryo]. / Reconstruction tridimensionnelle informatisée du segment rétrohépatique de la veine cave inférieure d'un embryon humain de 20mm.

The subdiaphragmatic venous drainage of the embryo is provided by the two caudal cardinal veins to which is added the subcardinal vein system, draining the mesonephros, the perispinal supracardinal veins and the umbilical and vitelline venous system. The anastomosis of certain segments of the embryonic venous structures and the disappearance of others are at the origin of the inferior vena cava. Since the 19th century, three-dimensional reconstruction of solid models from histological sections were developed. At present, the development of computerized three-dimensional reconstruction techniques allowed to operate a multitude of techniques of image processing and modeling in space. Three-dimensional reconstruction is a tool for teaching and research very useful in embryological studies because of the obvious difficulty of dissection and the necessity of introducing time as the fourth dimension in the study of organogenesis. This method represents a promising alternative compared to previous three-dimensional reconstruction techniques including Born technique. The aim of our work was to create a three-dimensional computer reconstruction of the retrohepatic segment of the inferior vena cava of a 20mm embryo from the embryo collection of Saints-Pères institute of anatomy (Paris Descartes university, Paris, France) to specify the path relative to the liver and initiate a series of computerized three-dimensional reconstruction that will follow the evolution of this segment of the inferior vena cava and this in a pedagogical and morphological research introducing the time as the fourth dimension.

Venous symptoms in C0 and C1 patients: UIP consensus document.

This UIP document provides an update on venous symptoms in CO and C1 patients. The correlation between venous symptoms and the presence of telangiectases and/or reticular veins is one of the most controversial topics in chronic venous disorders. As symptoms may be non-specific of chronic venous disease, it is important to differentiate venous symptoms from symptoms of other causes. Some data from the Bonn Vein Study suggest that the risk to develop venous symptoms is increased in women, advanced age and obesity. Treatment is based on physical advice, elastic compression, venoactive drugs, sclerotherapy, correction of foot static disorders and reduction of body weight. Future research should be promoted on venous symptoms in epidemiological and follow-up studies, about the relationship between female hormone levels and symptomatic telangiectasias, and between venous pain and foot static disorders in C0s C1s patients.

Three-dimensional modelling of the venous system by direct multislice helical computed tomography venography: technique, indications and results.

The aim of multislice helical computed tomography venography (CTV) is to provide a precise, global and three-dimensional (3D) anatomical depiction of the venous network of the lower limbs. A multislice and multidetector spiral CT acquisition of the lower limbs with contrast injection of the dorsal foot produces about 1000 slices in 30 seconds. Dedicated volume-rendering software can compute a realistic and interactive 3D model of the venous system in realtime. This new tool furnishes an accurate 3D representation of the whole venous system of the lower limb with a realistic 3D model of the limbs, providing a road map of the varicose networks complementary to the duplex ultrasound (DUS). CTV allows a complete morphological study of the deep veins, including the detection of anatomical variations and proximal venous obstruction, not easily detectable by DUS. In the case of deep vein thrombosis, it has been shown to be a good diagnostic tool, well correlated with sonography. It also demonstrates, in some cases, haemodynamic patterns which are not available by DUS, particularly for perforator veins and congenital vascular malformations. The use of virtual reality techniques enables a complete anatomical study of both deep and superficial veins including a virtual dissection of the limbs. CTV is also a great educational tool to learn anatomy of the venous system and a powerful research tool to improve our knowledge of venous anatomy.

Anatomy of the foot venous pump: physiology and influence on chronic venous disease.

The aim of this paper is to demonstrate the location of the venous foot pump using an anatomical study. Four hundred cadaveric feet were injected with green neoprene latex followed by a dissection. A coloured segmentation of the venous system was achieved. The Lejars' concept of the venous sole of the foot is incorrect: the true blood venous reservoir of the foot is located deeply in the plantar veins, between the plantar muscles. The medial and mostly lateral plantar veins converge into the plexus shaped calcaneal crossroad, where the blood is ejected upwards into the two posterior tibial veins. In addition, the several medial perforators of the foot directly connect the deep system (medial plantar veins) to the superficial venous system (medial marginal vein). This forms a true 'medial functional unit' which is unique in the limb given its directional flow is from deep to superficial. In conclusion, the plantar veins play an important role in the physiology of the venous return since a venous reservoir of 25 mL of blood is mobilized upwards with each step during walking. Therefore, the impairment of the foot pump by a static foot disorder should be considered as an important risk factor for chronic venous disease, and should be evaluated and corrected in any patient with venous insufficiency.

Static foot disorders: a major risk factor for chronic venous disease?

OBJECTIVE: To study the relationship between the static foot disorders (SFDs) and chronic venous disease (CVD). MATERIAL AND METHODS: A retrospective study of 824 feet in unselected 412 patients seen by one phlebologist using a standardized record form. A complete clinical, aetiological, anatomical and pathological elements (CEAP) classification was determined. Alleged venous symptoms were recorded using a 10-point visual analogue scale and scored using a customized questionnaire. A standardized measurement of the Djian-Annonier angle was used to quantify and identify the presence of any static disorder of the foot. RESULTS: There were 156 men (37.8%) and 256 women (62.2%) who were included in this study. A majority of patients (59.3%) had a CEAP classification of C3 or greater. Static disorders of the feet were found to be very common in the study population: 137 feet were hollow feet (16.6%) and 120 flat feet (14.5%). Thus, 31% of all of the feet had some form of SFD. A significant correlation was found between the incidence of SFD and body mass index (P < 0.01), the presence of symptoms (P<0.001) and prolonged standing during the day (>5 hours, P < 0.05). The severity of the CVD, represented by the CEAP clinical classes, was also found to be very significantly related to the SFD (P < 0.001). This correlation was found to be independent of age. CONCLUSION: Static disorders of the foot can be considered as an important risk factor that negatively affects CVD. In daily practice, it is often underestimated. This emphasizes the crucial importance of the detection of SFD during the clinical exam of all CVD patients. Correction of static disorders of the feet will improve symptoms due to the SFD, as well as those related to venous stasis. These results can easily be explained by improvement of foot pump efficacy during walking.