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1.
Int J Med Educ ; 13: 107-114, 2022 Apr 29.
Article de Anglais | MEDLINE | ID: mdl-35506483

RÉSUMÉ

Objectives: To evaluate student impressions of learning anatomy with mixed-reality and compare long-term information retention of female breast anatomy between students who learned with a mixed-reality supplement and their classmates who dissected cadavers. Methods: In Part 1, 38 first-year medical student volunteers, randomly divided into two groups, completed a mixed-reality module and cadaveric dissection on the female breast in a counterbalanced design. Participants also completed post-quizzes and surveys. Part 2 was a non-randomized controlled trial, 8-months after completing Part 1 and 6-months after a final exam on this content. The performance of twenty-two Part 1 participants and 129 of their classmates, who only dissected, was compared on a delayed post-quiz. Wilcoxon signed-rank test, Mann-Whitney U test, and 95% confidence intervals were used to analyze the data. Results: In Part 1, the Wilcoxon signed-rank test determined that participants expressed significantly more positive responses to mixed-reality and found mixed-reality easier for learning and teamwork. In Part 2, the Mann-Whitney U test found mixed-reality participants scored significantly higher on a delayed-post quiz than their classmates who only dissected (U = 928, p < .009). Conclusions:   This study suggests that medical students may prefer mixed-reality and that it may be an effective modality for learning breast anatomy while facilitating teamwork. Results also suggest that supplementing cadaveric dissection with mixed-reality may improve long-term retention for at least one anatomical topic. It is recommended that similar studies evaluate a larger sample and additional anatomical regions to determine the generalizability of these findings.


Sujet(s)
Étudiant médecine , Cadavre , Programme d'études , Évaluation des acquis scolaires/méthodes , Femelle , Humains , Apprentissage
2.
PLoS One ; 17(5): e0268075, 2022.
Article de Anglais | MEDLINE | ID: mdl-35511898

RÉSUMÉ

BACKGROUND: Short-stem implants in shoulder arthroplasty were recently developed and reported clinical outcomes are good. However, radiological analysis often reveals humeral stem misalignment in the frontal plane, along with high filling ratios that can lead to proximal bone remodeling under stress shielding. The aim of this cadaveric study was to test whether using compactors for standard-length (> 100 mm) stems to implant short (< 100 mm) stems reduces the risk of stem misalignment without compromising in terms of a higher filling ratio. METHODS: In a cadaveric study, twenty short stems were implanted using instrumentation for standard-length stems. Alignment and filling ratios were evaluated on anteroposterior radiographs for both the compactors and the stems. The angular deviations (α) from the humeral axis of the compactors and the short stems were measured. Misalignment was defined as |α| > 5°. Metaphyseal and diaphyseal filling ratios were calculated and defined as either high (≥ 0.7) or low (< 0.7). RESULTS: The median angular deviations of the compactors and the short stems were respectively 1.6° (range, 0.03 to 5.9°) and 1.3° (range, 0.3 to 9.6°). Nineteen of the 20 compactors (95%) and 17/20 short stems (85%) were correctly aligned. The proportions of correctly aligned compactors and stems were not significantly different (95% CI, -0.33 to 0.11; Z-test of proportions p = .60), and the respective angular deviations were significantly correlated (Spearman ρ = .60, p = 0.006). The diaphyseal and metaphyseal filling ratios of the compactors and the stems were all low. CONCLUSIONS: In this series of 20 implants in cadavers, the narrow short humeral stems implanted with compactors for standard-length stems were correctly aligned with the humeral axis. This approach may be a way to achieve both correct frontal alignment and low filling ratios.


Sujet(s)
Arthroplastie de l'épaule , Articulation glénohumérale , Prothèse d'épaule , Cadavre , Humains , Humérus/imagerie diagnostique , Humérus/chirurgie , Conception de prothèse , Articulation glénohumérale/chirurgie , Résultat thérapeutique
3.
BMC Musculoskelet Disord ; 23(1): 422, 2022 May 05.
Article de Anglais | MEDLINE | ID: mdl-35513813

RÉSUMÉ

BACKGROUND: Suture anchors (SAs) made of human allogenic mineralized cortical bone matrix are among the newest developments in orthopaedic and trauma surgery. Biomechanical properties of an allogenic mineralized suture anchor (AMSA) are not investigated until now. The primary objective was the biomechanical investigation of AMSA and comparing it to a metallic suture anchor (MSA) and a bioabsorbable suture anchor (BSA) placed at the greater tuberosity of the humeral head of cadaver humeri. Additionally, we assessed the biomechanical properties of the SAs with bone microarchitecture parameters. METHODS: First, bone microarchitecture of 12 fresh frozen human cadaver humeri from six donors was analyzed by high-resolution peripheral quantitative computed tomography. In total, 18 AMSAs, 9 MSAs, and 9 BSAs were implanted at a 60° angle. All three SA systems were systematically implanted alternating in three positions within the greater tuberosity (position 1: anterior, position 2: central, position 3: posterior) with a distance of 15 mm to each other. Biomechanical load to failure was measured in a uniaxial direction at 135°. RESULTS: Mean age of all specimens was 53.6 ± 9.1 years. For all bone microarchitecture measurements, linear regression slope estimates were negative which implies decreasing values with increasing age of specimens. Positioning of all three SA systems at the greater tuberosity was equally distributed (p = 0.827). Mean load to failure rates were higher for AMSA compared to MSA and BSA without reaching statistical significance between the groups (p = 0.427). Anchor displacement was comparable for all three SA systems, while there were significant differences regarding failure mode between all three SA systems (p < 0.001). Maximum load to failure was reached in all cases for AMSA, in 44.4% for MSA, and in 55.6% for BSA. Suture tear was observed in 55.6% for MSA and in 22.2% for BSA. Anchor breakage was solely seen for BSA (22.2%). No correlations were observed between bone microarchitecture parameters and load to failure rates of all three suture anchor systems. CONCLUSIONS: The AMSA showed promising biomechanical properties for initial fixation strength for RCR. Since reduced BMD is an important issue for patients with chronic rotator cuff lesions, the AMSA is an interesting alternative to MSA and BSA. Also, the AMSA could improve healing of the enthesis.


Sujet(s)
Lésions de la coiffe des rotateurs , Ancres de suture , Adulte , Amsacrine , Phénomènes biomécaniques , Cadavre , Os cortical , Humains , Adulte d'âge moyen , Coiffe des rotateurs/imagerie diagnostique , Coiffe des rotateurs/chirurgie , Lésions de la coiffe des rotateurs/imagerie diagnostique , Lésions de la coiffe des rotateurs/chirurgie , Techniques de suture
4.
Neurol India ; 70(2): 612-617, 2022.
Article de Anglais | MEDLINE | ID: mdl-35532628

RÉSUMÉ

Background: The surgical skill practice in neurosurgery is being compromised in the recent past owing to the duty time constraint, patient safety concerns, and medico-legal issues. Surgical practice outside the operating room is essential to enhance a resident's operative skills and to gain confidence. Objective: To discuss the experience of establishing an 'in-house neurosurgery skills laboratory' and various training sessions conducted with cadaveric and non-cadaveric simulation modules. Methods: A skills laboratory was set up in the existing resident teaching hall with nine workstations. Each station has been equipped with an operating table, surgeon's chair, basic microscope, endoscope, high-speed drill system, and a suction machine. Vascular anastomosis, high-speed drilling, and basic neuroendoscopy were planned on low-cost non-cadaveric modules. Craniotomy and various surgical approaches were designed on cadaveric modules obtained from the anatomy department. Result: A total of 18 residents in divided groups during their initial three semesters had participated in the non-cadaveric simulation courses. Twenty-six residents had participated and 12 sessions were conducted on the cadaveric modules. Three workshops were conducted and 20 residents and faculty members from five other institutions had participated in the cadaveric hands-on training session. Conclusion: A well-equipped skills laboratory provides an opportunity for the residents to acquire operative expertise in a similar atmosphere to that of the operating theater. A structured program comprising various operative practice sessions should be incorporated into the resident training program.


Sujet(s)
Internat et résidence , Cadavre , Compétence clinique , Programme d'études , Enseignement spécialisé en médecine , Humains
5.
Sci Rep ; 12(1): 7602, 2022 May 09.
Article de Anglais | MEDLINE | ID: mdl-35534595

RÉSUMÉ

Femoroplasty is a procedure where bone cement is injected percutaneously into a weakened proximal femur. Uncertainty exists whether femoroplasty provides sufficient mechanical strengthening to prevent fractures in patients with femoral bone metastases. Finite element models are promising tools to evaluate the mechanical effectiveness of femoroplasty, but a thorough validation is required. This study validated a voxel-based finite element model against experimental data from eight pairs of human cadaver femurs with artificial metastatic lesions. One femur from each pair was left untreated, while the contralateral femur was augmented with bone cement. Finite element models accurately predicted the femoral strength in the defect (R2 = 0.96) and augmented (R2 = 0.93) femurs. The modelled surface strain distributions showed a good qualitative match with results from digital image correlation; yet, quantitatively, only moderate correlation coefficients were found for the defect (mean R2 = 0.78) and augmented (mean R2 = 0.76) femurs. This was attributed to the presence of vessel holes in the femurs and the jagged surface representation of our voxel-based models. Despite some inaccuracies in the surface measurements, the FE models accurately predicted the global bone strength and qualitative deformation behavior, both before and after femoroplasty. Hence, they can offer a useful biomechanical tool to assist clinicians in assessing the need for prophylactic augmentation in patients with metastatic bone disease, as well as in identifying suitable patients for femoroplasty.


Sujet(s)
Ciments osseux , Maladies osseuses , Phénomènes biomécaniques , Cadavre , Fémur/imagerie diagnostique , Fémur/chirurgie , Analyse des éléments finis , Humains
6.
J Avian Med Surg ; 36(1): 28-38, 2022 May.
Article de Anglais | MEDLINE | ID: mdl-35526162

RÉSUMÉ

The objective of this study was to construct a calibration phantom for bone mineral density (BMD) measurements adapted to avian anatomy by quantitative computed tomography. The determination of BMD is important to assess avian osteoporosis in poultry at production facilities and to study biological features in association with flight patterns in birds. Quantitative computed tomography measured in Hounsfield units is a well-established technique for BMD measurements. Translation of Hounsfield units into the International System of Units (mg/cm3) requires the use of a calibration phantom. Although calibration phantoms for routine use in humans are commercially available, phantoms suited to avian anatomy are not. A liquid dipotassium hydrogen phosphate calibration standard was constructed out of commercially available materials, easily allowing for variations in size, bone diameter, and adaptation to avian skeletal anatomy. Periodically, quantitative computed tomography scans were performed to monitor constant correlation to the calibration standard over 3 months and to monitor for the potential influence of gas bubbling and water evaporation in the rods on BMD measurements. Finally, the calibration phantom was tested for BMD measurements with carcasses from 2 bird species, including 3 peregrine falcons (Falco peregrinus; 2 juvenile males, 1 adult female with inactive reproductive status) and 4 Eurasian kestrels (Falco tinnunculus; 1 juvenile and 2 adult males, 1 adult female with inactive reproductive status). Results demonstrated stability of the calibration phantom without the need to refill or replace rods, plus a stable correlation line (R 2 = .99) over the 3-month evaluation period. It was possible to place the phantom directly on the bird carcasses, close to the measured bones, to improve BMD analysis. As evaluated, the phantom appeared to be adaptive to avian skeletal anatomy. Moreover, it was possible to build the phantom within 24 hours from commercially available materials.


Sujet(s)
Densité osseuse , Tomodensitométrie , Animaux , Oiseaux , Cadavre , Femelle , Mâle , Fantômes en imagerie , Phosphates , Composés du potassium , Tomodensitométrie/médecine vétérinaire
7.
Biomed Res Int ; 2022: 8939359, 2022.
Article de Anglais | MEDLINE | ID: mdl-35419460

RÉSUMÉ

The aim of this study is to demonstrate the relationship between the proximal attachment of the coracobrachialis muscle and the short head of the biceps brachii and the distal attachment of the pectoralis minor. Their correlation with the bifurcated coracoid process (CP) will be also assessed. On the basis of these observations, a new classification of structures attached to the coracoid process is proposed. Classical anatomical dissection was performed on one hundred forty-five upper limbs. Three types of relationship between the coracobrachialis muscle and the short head of the biceps brachii were observed in the cadavers. In type I (occurring in 54%), the coracobrachialis and the short head of the biceps brachii created a common junction attached to a single CP. Type II was divided into two subtypes (a and b). Subtype IIa (frequency 10%) was represented by independent proximal attachments of the short head of the biceps brachii and the coracobrachialis muscles to the CP. In subtype IIb (frequency 5%), the coracobrachialis muscle was two-headed (the first head located under the second) and not connected to the short head of the biceps brachii; all heads were attached to a single CP. Type III (frequency 31%) was characterized by a two-headed coracobrachialis muscle, the first head originating from a bifurcated CP laterally to the short head of the biceps brachii and the second medially to this structure. Different variations connected with the mentioned structures could be problematic for surgeons during operations, so detailed knowledge of them could contribute to more efficient procedures.


Sujet(s)
Apophyse coracoïde , Muscles pectoraux , Bras , Cadavre , Humains , Muscles squelettiques
8.
PLoS One ; 17(4): e0266426, 2022.
Article de Anglais | MEDLINE | ID: mdl-35404971

RÉSUMÉ

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic substantially undermined medical education and healthcare systems. Owing to the pandemic in South Korea, most medical schools needed to be flexible when conducting online and offline classes, but the guidelines did not reflect the specificity of medical schools. This study described the impact of modified anatomy education schedules at the Seoul National University College of Medicine (SNUCM) on students' academic performance and satisfaction. METHODS: Anatomy education in SNUCM is divided into three regional units (the upper and lower limbs, trunk, and head and neck). Owing to the COVID-19 pandemic, the schedule was mixed with simultaneous and rotating schedules. The authors conducted exceptions for online lectures, cadaver dissections, and written and practical examinations in three classes of approximately 50 students each. Furthermore, the authors assessed students' performance using three sets of written and practical examinations, and students completed a questionnaire regarding modified anatomy laboratory schedules. RESULTS: Despite the pandemic events in Seoul and South Korea during the laboratory sessions, all sessions were completed without any confirmed COVID-19 cases among the students, faculty, and staff. Most of the scores on the written and practical examinations significantly decreased in 2020 compared to those in 2019. However, in the trunk session that used the virtual anatomy application, the score on the practical examination in 2020 was significantly higher than that in 2019. Over 70% (79 and 77 out of 105 respondents on the upper and lower limbs and trunk, respectively) and 53% (55/105) students reported that there were no significant difficulties in studying anatomy in a face-to-face laboratory. CONCLUSIONS: In conclusion, an adequate education program for cadaver dissection should be developed and provided to overcome the pandemic restrictions. The study findings could serve as a reference for anatomy education during the COVID-19 pandemic.


Sujet(s)
Anatomie , , Enseignement à distance , Étudiant médecine , Anatomie/enseignement et éducation , /épidémiologie , Cadavre , Humains , Pandémies , République de Corée/épidémiologie
9.
Adv Appl Microbiol ; 118: 91-113, 2022.
Article de Anglais | MEDLINE | ID: mdl-35461664

RÉSUMÉ

The human body provides a complex ecosystem for symbiotic habitation of a huge number of microorganisms. These commensal microorganisms provide a huge benefit to the living host by acting against many deadly infections. Once the host dies, many changes in the complex ecosystem of the human body take place. The personalized microbes of a human body undergo successional change as many exogenous microbes attack the nutrient-rich cadaver after death. The succession pattern change of microbes in human cadaver allows postulating different models for estimation of Postmortem time interval (PMI). Estimation of PMI has a broad prospect from the criminal investigation point of view. Though many techniques are being used nowadays to estimate PMI, all of them have their pros and cons. With the advent of advanced molecular biological techniques, studies on the thanatomicrobiome of a human cadaver have gained pace and provide a superior alternative for conventional methods of PMI estimation. This chapter summarizes the recent advancements in the changes in signature microflora postmortem with change in human microenvironment to postulate a consensus model for estimation of PMI.


Sujet(s)
Microbiote , Modifications postmortem , Autopsie , Cadavre , Humains
10.
Vet Surg ; 51(4): 638-647, 2022 May.
Article de Anglais | MEDLINE | ID: mdl-35383980

RÉSUMÉ

OBJECTIVE: To evaluate the angiosomes of the superior and inferior labial arteries in the cat and describe the use of a musculomucosal axial pattern flap incorporating each artery for reconstruction of palatal defects in cats. STUDY DESIGN: Cadaveric study and a series of two clinical cases. SAMPLE POPULATION: Five feline cadavers and two client-owned cats. METHODS: The common carotid arteries of five feline cadavers were injected with barium sulfate. Radiographs of excised tissue specimens were examined to map the location of the superior and inferior labial arteries and to visualize each angiosome available for an axial pattern flap. Labial musculomucosal flaps were utilized to reconstruct palatal defects in two live cats. RESULTS: The superior and inferior labia were predominantly perfused by the superior and inferior labial arteries, respectively, and the angiosome of each artery encompassed the majority of its respective labium. Comparative positive contrast angiograms revealed the vascular supply was located within the musculomucosal layer. Reconstruction of recurrent palatal defects utilizing musculomucosal flaps based on these angiosomes in two clinical cases was successful with complete survival of the flaps. CONCLUSION: The upper and lower lips were found to have robust vascular supplies within the musculomucosal layer which can support musculomucosal axial pattern flaps. CLINICAL SIGNIFICANCE: This information provides the veterinary surgeon with additional surgical options for reconstruction of central and caudal palatal defects in the cat.


Sujet(s)
Maladies des chats , Procédures de chirurgie reconstructive , Angiographie , Animaux , Artères , Cadavre , Chats/chirurgie , Humains , Procédures de chirurgie reconstructive/médecine vétérinaire , Lambeaux chirurgicaux/médecine vétérinaire
11.
Mymensingh Med J ; 31(2): 406-411, 2022 Apr.
Article de Anglais | MEDLINE | ID: mdl-35383758

RÉSUMÉ

Spleen is a haemo-lymph organ and belongs to the reticuloendothelial system of human body, develops from mesodermal proliferation between the two leaves of dorsal mesogastrium. The microscopic structure of spleen is variable depending on the developmental stage of the organ, and the age and immune status of the individual. In our country, we depend on foreign data which came from the subjects of different races and from the individuals under different geographic conditions. So the study was carried out to minimize the dependency on foreign standards and to identify the diameter of white pulp in different age and sex of the Bangladeshi individuals with a view to establish local data bank related to spleen of Bangladeshi people. This cross-sectional descriptive study was performed on 65 postmortem human spleens (34 of male and 31 of female) to find out the number and diameter of white pulp of spleen of Bangladeshi people by purposive sampling technique. And done in Autopsy laboratory of the Department of Forensic Medicine of Mymensingh Medical College, Bangladesh from 16th October 2016 to 15th January 2017. The samples were divided into three age groups including Group A (5-20 years), Group B (21-40 years) and Group C (41-60 years). Dissection was performed according to standard autopsy techniques. For statistical analysis, unpaired student 't' test was done. The mean±SD number of white pulp of male spleen was greater than female spleen in Group A, B and C but mean±SD diameter of white pulp of female spleen was found greater than male spleen in all groups. Comparison of number of white pulp between sexes showed that statistically there was no significant difference within all the age groups at p>0.05 level. No age change was evident in diameter of white pulp but in between sexes, diameter is greater in females than males. Mean difference of diameter of white pulp between sexes showed no significant difference within the age groups at p>0.05.


Sujet(s)
Rate , Adolescent , Adulte , Autopsie , Bangladesh , Cadavre , Enfant , Enfant d'âge préscolaire , Études transversales , Femelle , Humains , Mâle , Jeune adulte
12.
Mymensingh Med J ; 31(2): 416-420, 2022 Apr.
Article de Anglais | MEDLINE | ID: mdl-35383760

RÉSUMÉ

This study was done to see the changes in the number of Purkinje cells per square mm in different age groups of Bangladeshi people. This cross-sectional descriptive type of study was done on total 40 postmortem human cerebellums, in the Department of Anatomy, Mymensingh Medical College, Bangladesh from July 2016 to June 2017. The specimens were collected from morgue in the department of Forensic Medicine, Mymensingh Medical College, by purposive sampling technique. All the specimens were grouped into four categories: Group A (20 to 29 years), Group B (30 to 39 years), Group C (40 to 49 years) and Group D (50 to 59 years). Paraffin blocks of cerebellum were cut at 4-5µm thickness and stained with routine "Haematoxylin and Eosin" (H & E) stain. Estimation of number of Purkinje cell was done by using the counting circle and examined under the light microscope. In the present study, the mean±SD number of Purkinje cell was found 128.67±25.15 per sq mm in Group A, 136.53±34.45 in Group B per sq mm, 135.55±29.44 per sq mm in Group C, 127.69±35.31 per sq mm in Group D.


Sujet(s)
Cellules de Purkinje , Autopsie , Bangladesh , Cadavre , Études transversales , Humains
13.
Sci Rep ; 12(1): 6182, 2022 Apr 13.
Article de Anglais | MEDLINE | ID: mdl-35418662

RÉSUMÉ

Treatment of posterior meniscal roots tears evolved after biomechanical evidence of increased pressures on the tibiofemoral cartilage produced by this lesion and the subsequent accelerated development of arthritis or osteonecrosis observed clinically. However, little is known about the consequences of the detachment of the anterior roots. This in-vitro study analyzes the biomechanical changes in the tibiofemoral joint caused by avulsion of the anterior root of the lateral meniscus. The effectiveness of surgical root re-insertion to restore the pre-injured conditions is also evaluated. Using cadaveric knees at flexion angles from 0° to 90°, results show that the lesion significantly reduces the contact area and raises the pressure on the tibiofemoral cartilage of the injured compartment at all angles. Said modifications become larger at low flexion angles, which are the most frequent positions adopted by the knee in daily and sports activities, where they result similar to total meniscectomy. In-situ repair partially restores the contact biomechanics. Consequently, careful attention should be paid to proper diagnosis and treatment of detached anterior roots since the observed altered knee contact might induce similar degenerative problems in the cartilage as with completely detached posterior roots.


Sujet(s)
Maladies du cartilage , Traumatismes du genou , Lésions du ménisque externe , Phénomènes biomécaniques , Cadavre , Humains , Traumatismes du genou/chirurgie , Articulation du genou/chirurgie , Ménisques de l'articulation du genou/chirurgie , Amplitude articulaire , Lésions du ménisque externe/chirurgie
14.
BMC Anesthesiol ; 22(1): 107, 2022 04 15.
Article de Anglais | MEDLINE | ID: mdl-35428204

RÉSUMÉ

BACKGROUND: Modified thoracoabdominal nerves block through perichondrial approach (M-TAPA) was first described as a peripheral nerve block by Tulgar in 2019. This technique provides an analgesic effective range from Th7-11 with a single puncture per side. Although the efficacy and effective duration of M-TAPA have been reported, further examination is required. Therefore, this study aimed to evaluate the analgesic range and effective duration of M-TAPA in open gynecologic surgery. METHODS: Following approval, 10 adult female patients scheduled for open radical hysterectomy via a vertical incision or laparotomy using a midline incision from under the xiphoid process to the symphysis pubis were enrolled. The primary outcome was the number of anesthetized dermatomes at 2 and 24 h postoperatively. Secondary outcomes included numerical rating scale scores and the total amount of fentanyl used. Cadaveric evaluation was performed to assess the spread of the dye. RESULTS: The median numbers (interquartile range) of anesthetized dermatomes at 2 and 24 h postoperatively were 6 (5-7) and 6.5 (5-7) in the anterior cutaneous branch area and 5 (4-7) and 7 (5-7) in the lateral cutaneous branch area, respectively. There was an 85% chance of simultaneously acquiring analgesia in areas innervated by Th8-11, including complete block in areas innervated by the anterior cutaneous branches of Th9-10. Cadaveric evaluation showed the spread of the dye in Th8-11. CONCLUSIONS: M-TAPA may have analgesic effects in the areas supplied by the anterior cutaneous branches of Th8-11. TRAIL REGISTRATION: IRB approval (No.2700; registered on July 10, 2020) and registration (UMIN Clinical Trials Registry: UMIN000041137 ; registered on July 17, 2020).


Sujet(s)
Analgésiques , Douleur postopératoire , Adulte , Cadavre , Femelle , Procédures de chirurgie gynécologique , Humains , Douleur postopératoire/prévention et contrôle , Projets pilotes , Études prospectives , Échographie interventionnelle/méthodes
15.
J Biomech ; 136: 111069, 2022 May.
Article de Anglais | MEDLINE | ID: mdl-35381503

RÉSUMÉ

Advancements in technology and finite element software have made it possible to develop simulation-based exploration of subject-specific tibiofemoral joint kinematics. In this study, the goal was to develop baseline knee models that accurately predict anterior tibial displacement when undergoing a Lachman and pivot shift test. A total of 22 subject-specific adolescent tibiofemoral joint finite element representations were developed using FEBio. The models were subject to loading conditions established in the literature to simulate the two clinical tests. Anterior tibial translations that were measured through clinical, historical controls were used to validate the proposed models. A 95% confidence interval showed that the simulated Lachman and pivot shift tests of the juvenile knee models were not statistically different from the historical controls and were in accordance with the anterior tibial translations that were measured experimentally. Clinically, simulations are important in advancing the field of knee finite element modeling, particularly in pediatric applications where the surgeon must balance restoring full function in a patient who is skeletally immature and where the growth plate is vulnerable. The methodologies created in developing these foundational models can be utilized to build more anatomically complex finite element representations that can both predict ligament stresses in response to dynamic activities and analyze the effects of different insertion sites.


Sujet(s)
Lésions du ligament croisé antérieur , Instabilité articulaire , Adolescent , Ligament croisé antérieur/physiologie , Phénomènes biomécaniques/physiologie , Cadavre , Enfant , Humains , Articulation du genou/physiologie , Amplitude articulaire/physiologie , Rotation
16.
J Biomech ; 136: 111074, 2022 May.
Article de Anglais | MEDLINE | ID: mdl-35413514

RÉSUMÉ

This short communication provides details on customized Tekscan Analysis Programs (TAP) which extract comprehensive contact mechanics metrics from piezoelectric sensors in articulating joints across repeated loading cycles. The code provides functionality to identify regions of interest (ROI), compute contact mechanic metrics, and compare contact mechanics across multiple test conditions or knees. Further, the variability of identifying ROIs was quantified between seven different users and compared to an expert. Overall, the contribution of four variables were studied: two knee specimens; two points in the gait cycle; two averaging methods; and seven observers, to determine if variations in these values played a role in accurately quantifying the ROI. The relative error between the force ratio from each observer's ROI and the expert ROI was calculated as the output of interest. A multivariate linear mixed effects model was fit to the four variables for the relative error with an observer- and knee-specific random intercept. Results from the fitted model showed a statistically significant difference at the 0.05 level in the mean relative errors at the two gait points. Additionally, variability in the relative errors attributed to the observer, knee, and random errors was quantified. To reduce variability amongst users, by ensuring low inter-observer variability and increasing segmentation accuracy of knee contact mechanics, a training module and manual have been included as supplemental material. By sharing this code and training manual, we envisage that it can be used and modified to analyze outputs from a range of sensors, joints, and test conditions.


Sujet(s)
Démarche , Articulation du genou , Phénomènes biomécaniques , Cadavre , Humains , Genou
17.
Int J Implant Dent ; 8(1): 17, 2022 Apr 11.
Article de Anglais | MEDLINE | ID: mdl-35411479

RÉSUMÉ

PURPOSE: Many points concerning the structure of osseointegration and the surrounding jaw bone remain unclear, and its optimal histological form has yet to be identified. The aim of this study was to clarify the structural characteristics of peri-implant jaw bone on the micro- and nano-scales by quantitatively evaluating bone quality. METHODS: Five samples of human mandibular bone containing dental implants and one dentate sample that had been in place for some years while the donors were still alive were collected. Bulk staining was performed, and 100-µm-thick polished specimens were prepared. The osteon distributions in peri-implant bone and mandibular cortical bone were measured, after which alignment analysis of biological apatite (BAp) crystallites and anisotropy analysis of collagen fiber orientation using second-harmonic generation imaging were carried out. RESULTS: Osteons in the vicinity of the implant body ran parallel to it. In the cortical bone at the base of the mandible, however, most osteons were oriented mesiodistally. The preferential alignment of BAp crystallites was generally consistent with osteon orientation. The orientation of collagen fibers in peri-implant jaw bone resembled the concentric rings seen in normal cortical bone, but there were also fibers that ran orthogonally across these concentric fibers. CONCLUSIONS: These results suggest that the mechanical strain imposed by implants causes the growth of cortical bone-like bone in areas that would normally consist of cancellous bone around the implants, and that its structural characteristics are optimized for the load environment of the peri-implant jaw bone.


Sujet(s)
Implants dentaires , Apatites , Cadavre , Collagène/composition chimique , Humains , Mandibule/imagerie diagnostique , Ostéo-intégration
18.
Curr Biol ; 32(9): 2110-2119.e3, 2022 May 09.
Article de Anglais | MEDLINE | ID: mdl-35390283

RÉSUMÉ

Autophagy is a conserved quality control pathway that mediates the degradation of cellular components by targeting them to the lysosomes or vacuoles.1 Autophagy has been implicated in the regulation of some regulated cell death processes in animal systems.2 However, its function in developmentally controlled programmed cell death (dPCD) in plants remains little studied and controversial.3 Some studies have reported autophagy pro-survival roles,4,5 while others have suggested pro-death functions for autophagy,6,7 calling for further detailed investigations. Here, we investigated the role of autophagy in dPCD using the Arabidopsis root cap as an accessible and genetically tractable model system.8 In Arabidopsis, dPCD is an integral part of root cap differentiation, restricting root cap organ size to the root meristem.9 The root cap consists of two distinct tissues: the proximally positioned columella that is located at the very root tip and the lateral root cap (LRC) that flanks the root meristem up to its distal end at the start of the root elongation zone.10 We show that autophagic flux strongly increased prior to dPCD execution in both root cap tissues and depends on the key autophagy genes ATG2, ATG5, and ATG7. Systemic and organ-specific mutation of these genes shows delayed PCD execution and lack of postmortem corpse clearance in the columella but no defects in dPCD execution or corpse clearance in the distal LRC. Our results reveal a high degree of cell-type specificity in autophagy functions and suggest that autophagy roles in dPCD can considerably diverge between different cell types of the same plant organ.


Sujet(s)
Protéines d'Arabidopsis , Arabidopsis , Apoptose , Arabidopsis/métabolisme , Protéines d'Arabidopsis/génétique , Protéines d'Arabidopsis/métabolisme , Autophagie , Cadavre , Régulation de l'expression des gènes végétaux , Racines de plante/métabolisme , Plantes/métabolisme
19.
J Orthop Surg (Hong Kong) ; 30(1): 10225536221082343, 2022.
Article de Anglais | MEDLINE | ID: mdl-35388728

RÉSUMÉ

Purpose: This study aimed to determine the anatomical parameters of successful Sustentaculum Tali (ST) screw placement in the Asian population. Method: CT scans of unilateral feet of 110 participants were reviewed, retrospectively. The 3 D reconstruction of the calcaneus and morphometric measurements were performed by Mimics Research 19.0 and 3-Matic Research 11.0. Finally, six cadaveric feet were used for verification of the accuracy of the measurements. Results: We discovered a method to help place ST screw successfully: (1) The entry point located at the middle section of the lateral wall of posterior talar articular surface (PTAS), and the perpendicular distance from the entry point to the lateral edge of PTAS (PDEL) was 10.78 mm, (2) Screw was perpendicular to the z-axis, 66.98° to the y-axis (the longitudinal axis of the foot), (3) The length of the ST screw should be approximately 44.74 mm in male and 41.14 mm in female, and (4) The diameter of the ST screw should be approximately 4.0 mm in male and 3.5 mm in female. With this new method, all screws in six cadaveric feet were placed successfully into the middle of ST. Conclusions: In this study, we discovered a general approach to safely place ST screws in the Asian population, which may potentially help surgeons improve their success rate in surgical practice.


Sujet(s)
Calcanéus , Fractures osseuses , Vis orthopédiques , Cadavre , Calcanéus/imagerie diagnostique , Calcanéus/chirurgie , Femelle , Ostéosynthèse interne/méthodes , Fractures osseuses/chirurgie , Humains , Mâle , Études rétrospectives
20.
J Orthop Surg Res ; 17(1): 248, 2022 Apr 24.
Article de Anglais | MEDLINE | ID: mdl-35462535

RÉSUMÉ

BACKGROUND: Because of the broad anatomic variation in the course of the axillary nerve, several cadaveric studies have investigated the acromion-axillary nerve distance and its association with the humeral length to predict the axillary nerve location. This study aimed to analyze the acromion-axillary nerve distance (AAND) and its relation to the arm length (AL) in patients who underwent internal plate fixation for proximal humerus fractures. METHODS: The present prospective study involved 37 patients (15 female, 22 male; the mean age = 51 years, age range 19-76) with displaced proximal humerus fractures treated by open reduction and internal fixation. After anatomic reduction and fixation were achieved, the following parameters were measured in each patient before wound closure without making an extra incision or dissection: (1) the distance from the anterolateral edge of the acromion to the course of the axillary nerve was recorded as the acromion-axillary nerve distance and (2) the distance from the anterolateral edge of the acromion to the lateral epicondyle of the humerus was recorded as arm length. The ratio of AAND to AL was then calculated and recorded as the axillary nerve index (ANI). RESULTS: The mean AAND was 6 ± 0.36 cm (range 5.5-6.6), and the mean arm length was 32.91 ± 2.9 cm (range 24-38). The mean axillary nerve ratio was 0.18 ± 0.02 (range 0.16 to 0.23). There was a significant moderate positive correlation between AL and AAND (p = 0.006; r = 0.447). The axillary nerve location was predictable in only 18% of the patients. CONCLUSION: During the anterolateral deltoid-splitting approach to the shoulder joint, 5.5 cm from the anterolateral edge of the acromion could be considered a safe zone to prevent possible axillary nerve injury.


Sujet(s)
Acromion , Fractures de l'épaule , Adulte , Sujet âgé , Bras , Cadavre , Femelle , Ostéosynthèse interne , Humains , Humérus/chirurgie , Mâle , Adulte d'âge moyen , Études prospectives , Fractures de l'épaule/chirurgie , Jeune adulte
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