Anatomical Variability Research Articles

Advantages of customization of osseointegrated implants in transfemoral amputees: a comparative analysis of surgical planning

BackgroundCommercially available osseointegrated devices for transfemoral amputees are limited in size and thus fail to meet the significant anatomical variability in the femoral medullary canal. This study aimed to develop a customized osseointegrated stem to better accommodate a variety of femoral anatomies in transfemoral amputees than off-the-shelf stems. Customization is expected to enhance cortical bone preservation and increase the stem-bone contact area, which are critical for the long-term stability and success of implants.MethodsA customized stem (OsteoCustom) was designed based on the statistical shape variability of the medullary canal. The implantability of the OsteoCustom stem was tested via 70 computed tomography (CT) images of human femurs and compared to that of a commercial device (OFI-C) for two different resection levels. The evaluations included the volume of cortical bone removed and the percentage of stem-bone contact area for both resection levels. Statistical significance was analyzed using paired and unpaired t tests.ResultsThe OsteoCustom stem could be virtually implanted in all 70 femurs, while the OFI-C was unsuitable in 19 cases due to insufficient cortical thickness after implantation, further emphasizing its adaptability to varying anatomical conditions. The OsteoCustom stem preserved a greater volume of cortical bone than did the OFI-C. In fact, 42% less bone was removed at the proximal resection level (3.15 cm³ vs. 5.42 cm³, p ≤ 0.0001), and 33% less at the distal resection level (2.25 cm³ vs. 3.39 cm³, p = 0.003). The stem-bone contact area was also greater for the OsteoCustom stem, particularly at the distal resection level, showing a 20% increase in contact area (52.3% vs. 32.2%, p = 0.002) compared to that of the OFI-C.ConclusionsThe OsteoCustom stem performed better than the commercial stem by preserving more cortical bone and achieving a greater stem–bone contact area, especially at distal resection levels where the shape of the medullary canal exhibits more inter-subject variability. Optimal fit in the distal region is of paramount importance for ensuring the stability of osseointegrated implants. This study highlights the potential benefits of customized osseointegrated stems in accommodating a broader range of femoral anatomies, with enhanced fit in the medullary canal.

Morphological and morphometric analysis of the Sacral Hiatus using lumbosacral spine CT scans: clinical relevance in Caudal Epidural Analgesia.

To conduct a morphological and morphometric analysis of the sacral hiatus (SH) using lumbosacral spine CT scans and to evaluate its clinical relevance in caudal epidural analgesia (CEA). This retrospective study analyzed 77 lumbosacral spine CT scans from a diverse patient population. The shape of the SH was classified into common types: inverted U, inverted V, irregular, and bilobed. Morphometric measurements included the length, width, and depth at the apex of the SH. The apex level of the SH was also determined in relation to the sacral vertebrae, and statistical analysis was performed to identify any correlation between the apex level and the morphometric dimensions. The most frequent SH shape was inverted U (68.83%), followed by inverted V (20.77%), irregular (9%), and a single instance of a bilobed shape (1.29%). The apex of the SH was most commonly located at the level of the S4 vertebra (75.32%), followed by the S3 vertebra (20.77%), S5 in two (2.59) and S2 in one (1.29%). No significant correlation was found between the level of the apex and the length, width, or depth of the SH. These findings indicate a high degree of anatomical variability in the SH, independent of the apex level. The anatomical variability of the SH, as observed in this study, underscores the need for individualized assessment during CEA. The lack of correlation between the apex level and the morphometric dimensions of the SH highlights the importance of imaging modalities such as ultrasound or fluoroscopy to ensure precise localization and effective analgesia administration. These insights can improve clinical outcomes by enhancing the accuracy and safety of caudal epidural procedures.

Morphology and anatomical variability of the external auditory canal: A population-based MRI study

BackgroundThe external auditory canal (EAC) exhibits a complex morphology and strong inter-individual variations. However, these have not yet been comprehensively described in the literature. PurposeThis study aims to determine the width, height and cross-sectional area of the cartilaginous portion of the EAC and to describe the three-dimensional morphology and variability of different EACs. MethodsMagnetic resonance imaging was performed on 870 subjects (401 male, 469 female, resulting in 1740 EACs) who participated in the longitudinal, population-based cohort study ‘Study of Health in Pomerania–START-3’. The height and width were measured in the cartilaginous part of the EAC, between the first and second bend. The variability of the EAC morphology was visualized in three-dimensional models. ResultsThe mean height (vertical length) of the EAC was 8.62 mm (SD = 2.42) on the right, 8.47 mm (SD = 2.36) on the left. The width (horizontal length) was 4.08 mm (SD = 1.6) on the right, 3.93 mm (SD = 1.64) on the left. The EAC cross-section was 28.6 mm2 (SD = 15.19) on the right, 27.15 mm2 (SD = 14.33) on the left. The average cross-sectional area of the EAC in men was higher than in women. Subjects with larger body size had larger cross-sectional areas. Subjects with higher body mass index tended to have smaller cross-sections. Although the average EAC had an oval shape, a three-dimensional comparison of different EACs revealed strong individual variation in morphology. ConclusionThis study enhances the understanding of otolaryngologists and anatomists regarding the complex morphology and variability of the cartilaginous portion of the EAC.

MORPHOMETRIC CHARACTERISTICS OF NECK PARAMETERS IN THE PERINATAL PERIOD OF ONTOGENESIS

This study aims – to establish the normative morphometric parameters of the neckcircumference, anterior- posterior diameter, height, and width during the perinatal periodof ontogenesis, after which the parameters will be used to construct anatomical models. Material and Methods. The study was conducted on 63 human fetuses aged 4 to10 months and 7 newborns (including 5 isolated organ systems). To create anatomicalmodels, the well-known dimensions of the neck in all age groups were determined usinga centimeter tape and a caliper. The neck circumference was measured at the level of thehyoid bone. The anteroposterior neck diameter was defined as the distance between thebody of the hyoid bone and the VII spinous process of the cervical vertebra. Neck heightwas measured from the upper to the lower neck borders. Neck width was determined inthe frontal plane at the level of the hyoid bone between the lateral edges of the neck.Statistical analysis of the data was performed using the licensed program RStudio.Results. A morphometric analysis of the average values of the well-known neck parameters,namely its circumference, anterior- posterior diameter, height, and width, was conductedin the perinatal period of ontogenesis. The analysis revealed that these parameters exhibitnon-synchronous growth throughout the studied period of the development, with periodsof intensive and relative growth. A correlation analysis was conducted between allmorphometric parameters of the neck of fetuses and newborns. The results demonstratedthat the correlation coefficients between the values of all paired correlation coefficientswere positive and close to 1 (≥0.90), indicating a strong positive correlation between allstudied parameters. A statistical analysis of the data from the Conover- Iman test indicatesthat the median values of the morphometric parameters of the neck cannot be consideredreliable for the pairs «9 months – 10 months» and «10 months – Newborns». This isjustified by the fact that individual anatomical variability is inherent in each individual,and these periods of the development are critical for the neck area. The constructedstandard anatomical models of the morphometric parameters of the neck will serve asa norm for the subsequent determination of certain morphological deviations, which willthen be used to establish variants of the structure and developmental defects of the neck.Conclusions. 1. During the perinatal period of the development, the well-known parametersof the neck, namely its circumference, anterior- posterior diameter, height and width,increase asynchronously. 2. The average values of the morphometric parameters of the neckcircumference and anterior- posterior diameter during the perinatal period of ontogenesisindicate that one period of accelerated development is evident, occurring between the 7thand 9th month of intrauterine development for the neck circumference and between the 6thand 9th month of development for the anterior- posterior diameter of the neck. Two periods ofaccelerated development are observed for the parameters of neck height and width. For neckheight, these periods are from the 5th to the 7th month of development and from the 8th to the9th month of development. For neck width, the periods are from the 4th to the 5th month ofthe development and from the 7th to the 9th month of intrauterine development. In all otherperiods of development, the morphometric parameters of the neck exhibit a slight increase. 3.Based on the arithmetic mean data of the circumference, anterior- posterior diameter, height,and width of the neck, models for predicting the normative morphometric parameters of fetusesand newborns were constructed. The systematized data on the peculiarities of spatial andtemporal transformations of the morphometric parameters of the neck circumference, anteriorposterior diameter, neck height and width, followed by their construction of mathematicalmodels, will contribute to the individualization of the norm, improvement of early diagnosticmethods and development of new methods of surgical correction of congenital neck defects.

VARIABILITY REGULARITIES OF THE CEPHALOMETRICAL PARAMETERS OF THE HUMAN FETAL SKULL

The purpose of the study – to find out the regularities of the age dynamics of cephalometricparameters and critical periods of the development of the skull of human fetuses.Material and methods. 60 preparations of skulls and 63 computer tomograms of theheads of human fetuses aged from 4 to 10 months of intrauterine development werestudied. A complex of morphological research methods was applied, which includedanthropometry, morphometry, three- dimensional reconstruction and statistical analysis.Linear and angular parameters of the skull were measured, and their ratios, characterizingthe constitutional and cephalometric parameters of the individual (cranial and facialindices), were determined. Results. The analysis of absolute cephalometric parameters (longitudinal, transversediameters, skull circumference, height dimensions) demonstrated the predominanceof logarithmic dynamics of their changes in human fetuses, that is explained by theiraccelerated growth during the 4th month of intrauterine development and a slowdownduring the 7th month with subsequent acceleration in the 8th month of prenatal development.A straight trend line is characteristic of the V-S height (distance from the Sella turcica tothe highest point of the skull), which is explained by the accelerated growth of the anteriorand posterior cranial fossae, while the sphenoid bone and the region of anterior fontanelledevelop in a consistent direction and pace. The linear pattern of growth is typical for theforamen magnum, hard palate, length of the orbit, body and ramus of the mandible, aswell as for relative cephalometric parameters that show a wide range of morphometricvariability. Analysis of the scatter diagram using the method of weighted least squaresdistances showed a decrease in the angle of the front part of the cranial base until the5th month of intrauterine development, followed by an increase in the 7th-8th months ofprenatal development. Multivariate regression analysis of the relationship between fetalage, cranial index and the value of the angle of the front part of the cranial base showedpronounced anatomical variability, which depended on the craniotype. Before the end ofintrauterine development, the N-S-Ba angle increases, but at the beginning of the fetal periodof ontogenesis, it decreases. It has the smallest values in dolichocephals compared to othercraniotypes. The largest values of this angle are found in mesocephals at the beginning of thefetal period, and in brachiocephals and mesocephals at the end of intrauterine development.Conclusions. 1. Critical periods of skull development in the fetal period of humanontogenesis are the 4-5th and 7-8th months, during which uneven changes in absoluteand relative craniometric parameters are observed. 2. The value of the angle of the frontpart of the cranial base can be a diagnostic and prognostic indicator in combinationwith the cranial index, which characterize the craniotype of the individual, during themonitoring of the normal development of the skull and brain of the fetus.

Hysteroscopic Management of Complete Vaginal and Uterine Septum with Double Cervix: Tips & Tricks for a Safe Surgery

The septate uterus is the most common uterine abnormality, comprising 35% of all identified uterine malformations. According to the ESHRE/ESGE 2013 classification, the class U2bC2V1 is a rare congenital malformation characterized by a complete septate uterus with double cervix and nonobstructive longitudinal vaginal septum. to share the decision-making process, the preoperative ultrasonographic assessment and our step-by-step hysteroscopic surgery technique to manage this complex malformation: including how to access the septate uterine cavity, the resection of the septum and its post-operative management. The goal of the surgical treatment is to restore the regular morphology of the vaginal canal and the uterine cavity with the right amount of myometrium. we present video footage of a hysteroscopic approach at a tertiary care academic medical center for managing a 21-year-old patient with a symptomatic uterine septum with double cervix and non-obstructive longitudinal vaginal septum. Both the Intraoperative and postoperative periods were uneventful: a complete resolution of the vaginal septum and creation of a single uterine cavity were obtained. Due to the significant anatomic variability of this condition, this type of surgery can be challenging. The goal of this video is also educational, aiming to illustrate a reproducible technique that can be utilized by younger or less experienced surgeons. In our experience, this hysteroscopic technique appears to be a valid option for patients with symptomatic Mullerian malformation or those with a history of recurrent miscarriages or unexplained infertility.

Finite Element Analysis of Skin Deformation and Puncture for Microneedle Array Design.

The mechanics of microneedle insertion have thus far been studied in a limited manner. Previous work has focused on buckling and failure of microneedle devices, while providing little insight into skin deformation, puncture, and the final positioning of needle tips under full microneedle arrays. The current study aims to develop a numerical approach capable of evaluating deformation and puncture conditions for full microneedle array designs. The analysis included a series of finite element submodels used to calibrate the microneedle-epidermal interface for failure properties using traction-separation laws. The single needle model is validated using experimental data and imaging, including results from a customized nanoindentation procedure to measure loads and displacements during microneedle insertion. Upon validation, full microneedle arrays are implemented in a 3 D finite element model and a design framework is developed, allowing evaluation of different design variables (i.e. needle shape, material, spacing) with respect to outputs relevant to successful microneedle performance. Results from the model include skin deformation, force to puncture, penetration depth, and the punctured state at each microneedle tip. In addition to microneedle parameters, patient parameters such as subcutaneous tissue thickness are included to evaluate the sensitivity of different microneedle designs to expected patient and anatomical region variability.

Predictors of discordance between CT-derived fractional flow reserve (CT-FFR) and △CT-FFR in deep coronary myocardial bridging

ObjectiveTo compare the performance between CT-derived fractional flow reserve (CT-FFR) and ΔCT-FFR measurements in patients with deep myocardial bridging (MB) along the left anterior descending artery, and explore the potential predictors of discordance. Methods175 patients with deep MB who underwent coronary computed tomography angiography (CCTA) and CT-FFR assessment were included. Clinical, anatomical and atherosclerotic variables were compared between patients with concordant and discordant CT-FFR and ΔCT-FFR. Results30.9 % patients were discordantly classified, in which 94.4 % patients were classified as CT-FFR+/△CT-FFR-. The discordant group showed significantly higher upstream stenosis degree, distance from MB to the aorta, △CT-FFR (P 0.007, 0.009 and 0.002, respectively), and lower CT-FFR (P < 0.001). In multivariate analysis, upstream stenosis degree (P 0.023, OR 1.628, 95 % CI: 1.068–2.481) and distance from MB to the aorta (P 0.001, OR 1.04, 95 % CI: 1.016–1.064) were independent predictors for discordance between CT-FFR and ΔCT-FFR. ConclusionThe discordance between CT-FFR and ΔCT-FFR measurements underscores the challenges in clinical decision-making, necessitating tailored approaches for MB evaluation.

SPECTRAL-DOMAIN OCT INSIGHTS INTO IDIOPATHIC EPIRETINAL MEMBRANE SURGERY OUTCOMES.

This study aims to assess the prognostic value of a classification system that includes the presence of ectopic inner foveal layers (EIFL) and other anatomical variables identified in spectral-domain optical coherence tomography (SD-OCT) for idiopathic epiretinal membrane (ERM) surgery. A descriptive-analytic, longitudinal, retrospective study was conducted on patients with idiopathic ERMs treated with pars plana vitrectomy (PPV) from January 2017 to December 2021. Clinical data and SD-OCT images were reviewed pre-surgery and 12 months post-surgery. The primary outcome measured was best corrected visual acuity (BCVA) before and after surgery, analyzing the impact of anatomical factors on BCVA in patients undergoing ERM surgery. The study included 342 eyes from 323 patients. Post-surgical evaluations showed significant reductions in central foveal thickness (CFT) across all ERM stages, with most stage 4 ERMs regressing to stage 3. The mean improvement in BCVA was significant for all stages, with earlier stages showing better results. Presence of macular edema (ME) and ellipsoid zone (EZ) disruption were significant predictors of post-surgical BCVA, while disorganization of the retinal inner layer (DRIL) showed association with visual recovery but was not conclusively predictive. The study highlights the importance of SD-OCT in assessing retinal changes in idiopathic ERMs, demonstrating the prognostic value of EIFL stage scheme and other anatomical variables like EZ disruption and ME presence on BCVA. These findings offer insights for surgical prognostication and the potential for personalized treatment strategies.

Predictors for thoracic aortic growth in patients with type B aortic dissection after thoracic endovascular aortic repair.

To identify independent predictors of thoracic aortic growth in patients with type B aortic dissection (TBAD) undergoing thoracic endovascular aortic repair (TEVAR). A retrospective analysis of the patients undergoing TEVAR for TBAD or intramural hematoma (IMH) from April 2014 to April 2023 was performed. The baseline morphological data of TBAD was established through computed tomography angiography (CTA) before discharge. Patients were divided into two groups based on aortic growth: growth and no growth. Aortic growth defined as an increase ≥5mm in thoracic maximal aortic diameter during any serial follow-up CTA measurement. Logistic regression following propensity score matching (PSM) was used to identify independent predictors for aortic growth. Receiver operating characteristic curve and cutoff value of independent predictors were calculated. Linear regression was used to establish a correlation between anatomical variables and follow-up aortic diameter. A total of 145 patients with TBAD (n = 122) or IMH (n = 23) undergoing TEVAR were included, with a male of 83.4% and a mean age of 56 ± 14.1years. Patients in growth group and no growth group was 26 (17.9%) and 119 (80.1%), respectively. After using PSM method, matched regression analysis showed residual maximal tear diameter (OR = 0.889, 95% CI 0.830-0.952, p = 0.001) and follow-up aortic diameter (OR = 0.977, 95% CI 0.965-0.989, p < 0.001) were independent predictors for aortic growth. The cutoff value was 8.55mm for residual tear diameter and 40.65mm for follow-up maximal aortic diameter. The residual maximal tear diameter showed a linear correlation with follow-up aortic diameter (DW = 1.74, R2 = 6.2%, p = 0.033). This study suggested that residual maximal tear diameter >8.55mm and follow-up aortic diameter >40.65mm could predict aortic growth in patients with TBAD undergoing TEVAR.

Variations of the abductor pollicis longus tendon and its insertion in the Thai population: Cadaveric study with clinical relevance

BackgroundThe abductor pollicis longus (APL) tendon exhibits significant anatomical variability, which is crucial for understanding its clinical implications in surgeries involving the thumb. While several studies have documented these variations in different populations, a systematic classification providing insights for surgical interventions targeting the thumb and its associated anatomical structures is rare. MethodsThis cadaveric study involved the dissection of 87 upper extremities from 44 embalmed cadavers (22 males, 22 females). The APL tendons were meticulously dissected, and the number of tendons slips and their insertion sites were recorded. Data were analyzed using Chi-square and Fisher's exact tests to assess differences in insertion sites between sexes and sides. ResultsThe number of APL tendon slips distal to the first extensor compartment ranged from 1 to 5, with double slips being the most common configuration. The primary insertion site was consistently the base of the first metacarpal bone, observed in all specimens. Secondary insertion sites included the abductor pollicis brevis muscle (67.82 %), trapezium (17.24 %), opponens pollicis muscle (5.75 %), and proximal phalanx (2.30 %). Statistical analysis showed no significant differences in the insertion sites between sides and sexes. A new classification system for APL tendon slips was developed, categorizing them into three main types (Type I, II, III), and two minor types (Type IV and V), based on the number and insertion sites of the tendons. Type II with double tendon slips was the most prevalent (48.28 %). Symmetrical findings were found in 21 cases (48.84 %), with subtype IIb being the most common pattern. ConclusionThis study highlights significant anatomical variations of the APL tendon in the Thai population, with important clinical implications for surgical planning and treatment of thumb-related conditions. The proposed classification system provides a structured framework for understanding these variations, aiding in the diagnosis and surgical management.

Flow reduction due to arterial catheterization during stroke treatment - A computational study using a distributed compartment model.

The effectiveness of various stroke treatments depends on the anatomical variability of the cerebral vasculature, particularly the collateral blood vessel network. Collaterals at the level of the Circle of Willis and distal collaterals, such as the leptomeningeal arteries, serve as alternative avenues of flow when the primary pathway is obstructed during an ischemic stroke. Stroke treatment typically involves catheterization of the primary pathway, and the potential risk of further flow reduction to the affected brain area during this treatment has not been previously investigated. To address this clinical question, we derived the lumped parameters for catheterized blood vessels and implemented a corresponding distributed compartment (0D) model. This 0D model was validated against an experimental model and benchmark test cases solved using a 1D model. Additionally, we compared various off-center catheter trajectories modeled using a 3D solver to this 0D model. The differences between them were minimal, validating the simplifying assumption of the central catheter placement in the 0D model. The 0D model was then used to simulate blood flows in realistic cerebral arterial networks with different collateralization characteristics. Ischemic strokes were modeled by occlusion of the M1 segment of the middle cerebral artery in these networks. Catheters of different diameters were inserted up to the obstructed segment and flow alterations in the network were calculated. Results showed up to 45% maximum blood flow reduction in the affected brain region. These findings suggest that catheterization during stroke treatment may have a further detrimental effect for some patients with poor collateralization.

Anatomic variability of tricuspid leaflets and right ventricle in Ebstein's anomaly: Anatomic and morphogenetic considerations

Anatomic variability of tricuspid leaflets and right ventricle in Ebstein's anomaly: Anatomic and morphogenetic considerations

Anatomy of Inferior Mesenteric artery: A Cadaveric Study

Introduction: A comprehensive knowledge of the varied anatomy of the inferior mesenteric artery (IMA) can be important in surgeries in the region of the colon and rectum.Methods: We analyzed 50 fresh cadavers in the department of Anatomy, Faculty of Medicine Ragama from 2022 to 2024. Latarjet’s classification was used for the IMA branching pattern. The anatomical relationships of the IMA left colic artery (LCA), sigmoidal artery (SA), and superior rectal artery (SRA) were observed, and the length from the origin of the IMA to the point of branching into the LCA or common trunk of LCA and SA was measured. The relationship between LCA and inferior mesenteric vein (IMV) was also observed. The data was presented as the value / percentage.Results: Majority showed Type A branching pattern 35/50 (70%). The respective lengths from the origin of the IMA to the beginning of LCA were measured and expressed as (mm) (mean ± SD) for each type; Type A 33.4 ± 4.7, Type B 36.5 ± 5.4, Type C 39.2 ± 8.6. The number of LCA under IMV in type A (51%); type B (54%); type C (62%) respectively. There was no statistically significant difference among the three types.Conclusion: Our study showed that type A branching pattern of LCA was the commonest. It is also observed that almost similar incidence of LCA traversing above and beneath the IMV.

Three-dimensional anatomic features of the mitral valve that predict systolic anterior motion occurring during dobutamine stress echocardiography.

Left ventricular outflow tract obstruction related to systolic anterior motion (SAM) of the mitral valve is a common complication of dobutamine stress echocardiography (DSE). However, the mechanisms underlying SAM have not been fully characterized. The objective of the present study was to use three-dimensional echocardiography to identify anatomic features of the mitral valve that predispose to SAM during DSE. We retrospectively evaluated consecutive patients included prospectively in our database and who had undergone 3D echocardiography (including an assessment of the mitral valve) before DSE. Patients who had developed SAM during DSE (the SAM+ group) were matched 2:3 with patients who did not (the SAM- group). One hundred patients were included (mean age: 67±10). Compared with SAM- patients (n=60), SAM+ patients (n=40) had a lower mitral annular area, a smaller perimeter, and a smaller diameter (p<.01 for all, except the anteroposterior diameter). The SAM+ group had also a narrower mitral-aortic angle (126±12° vs. 139±11° in the SAM- group; p<.01) and a higher posterior mitral leaflet length (1.4±.27cm vs. 1.25±.29, respectively; p<.01). Furthermore, the mitral annulus was more spherical, more flexible, and more dynamic in SAM+ patients than in SAM- patients (p<.05 for all). In a multivariate analysis of anatomic variables, the mitral-aortic angle, the mitral annular area, and posterior leaflet length were independent predictors of SAM (p ≤ .01 for all). In a multivariate analysis of standard echo and hemodynamic variables, the presence of wall motion abnormalities at rest (p<.01) was an independent predictor of SAM. SAM during DSE is multifactorial. In addition to the pharmacologic effects of dobutamine on the myocardium, 3D echocardiographic features of the mitral valve (a smaller mitral annulus, a narrower mitral-aortic angle, and a longer posterior leaflet) appear to predispose to SAM.

High-throughput analysis of dendrite and axonal arbors reveals transcriptomic correlates of neuroanatomy

Neuronal anatomy is central to the organization and function of brain cell types. However, anatomical variability within apparently homogeneous populations of cells can obscure such insights. Here, we report large-scale automation of neuronal morphology reconstruction and analysis on a dataset of 813 inhibitory neurons characterized using the Patch-seq method, which enables measurement of multiple properties from individual neurons, including local morphology and transcriptional signature. We demonstrate that these automated reconstructions can be used in the same manner as manual reconstructions to understand the relationship between some, but not all, cellular properties used to define cell types. We uncover gene expression correlates of laminar innervation on multiple transcriptomically defined neuronal subclasses and types. In particular, our results reveal correlates of the variability in Layer 1 (L1) axonal innervation in a transcriptomically defined subpopulation of Martinotti cells in the adult mouse neocortex.

The Incidence of Obstructive Sleep Apnea in Patients with Dento-Skeletal Malformation.

Purpose: The aim of this article is to analyze the incidence of undiagnosed obstructive sleep apnea (OSA) in patients affected by dento-skeletal malformation. We also evaluated the patterns most affected by the condition and calculated the post surgical changes. Methods: We conducted a retrospective cohort study on 71 patients including 35 men and 36 women. The patients studied were affected by dento-skeletal class II and III malformations and underwent bimaxillary orthognathic surgery in all cases. Patients were evaluated with polysomnography before surgery and at least 6 months after surgery to assess any improvement or worsening of the apnea hypopnea index (AHI) index. Regarding AHI evaluation criteria, an AHI > 5 was considered indicative of OSA, 4 < AHI < 5 was considered borderline and AHI < 4 was considered indicative of non-OSA. We also considered demographic variables like age at the time of intervention and gender, and anatomical variables like the pattern of the dento-skeletal deformity and the presence or absence of maxillary hypoplasia. Qualitative variables were described as absolute and relative frequencies, while quantitative variables were summarized as mean and standard deviation. To quantitatively express the relationship between two variables, the correlation coefficient was calculated. The covariance array was used to evaluate multiple correlations. Results: Our study shows that there is a significant percentage (33%) of patients who undergo orthognathic surgery with an AHI > 5 and also a percentage of patients (11%) who can be considered to be "borderline." It emerges that the pattern most at risk is the one characterized by retruded maxilla and patients with dento-skeletal class II. Considering the post surgical period, the statistical analysis shows that after surgery, only 8% of malformed patients present an AHI > 5, compared to the 20.5% described in the Italian population. Conclusions: In patients who receive orthognathic surgery, the presence of obstructive sleep apnea is significantly higher than in the general population. When planning the surgical correction of a dento-skeletal malformation, the surgeon must aim not only for the esthetics results, but also for proper stomatognathic and respiratory function; this cannot be achieved without taking polysomnography information into account.

Anatomic variability of the human femur and its implications for the use of artificial bones in biomechanical testing.

Aside from human bones, epoxy-based synthetic bones are regarded as the gold standard for biomechanical testing os osteosyntheses. There is a significant discrepancy in biomechanical testing between the determination of fracture stability due to implant treatment in experimental methods and their ability to predict the outcome of stability and fracture healing in a patient. One possible explanation for this disparity is the absence of population-specific variables such as age, gender, and ethnicity in artificial bone, which may influence the geometry and mechanical properties of bone. The goal of this review was to determine whether commercially available artificial bones adequately represent human anatomical variability for mechanical testing of femoral osteosyntheses. To summarize, the availability of suitable bone surrogates currently limits the validity of mechanical evaluations of implant-bone constructs. The currently available synthetic bones neither accurately reflect the local mechanical properties of human bone, nor adequately represent the necessary variability between various populations, limiting their generalized clinical relevance.

A deep learning anthropomorphic model observer for a detection task in PET.

Lesion detection is one of the most important clinical tasks in positron emission tomography (PET) for oncology. An anthropomorphic model observer (MO) designed to replicate human observers (HOs) in a detection task is an important tool for assessing task-based image quality. The channelized Hotelling observer (CHO) has been the most popular anthropomorphic MO. Recently, deep learning MOs (DLMOs), mostly based on convolutional neural networks (CNNs), have been investigated for various imaging modalities. However, there have been few studies on DLMOs for PET. The goal of the study is to investigate whether DLMOs can predict HOs better than conventional MOs such as CHO in a two-alternative forced-choice (2AFC) detection task using PET images with real anatomical variability. Two types of DLMOs were implemented: (1) CNN DLMO, and (2) CNN-SwinT DLMO that combines CNN and Swin Transformer (SwinT) encoders. Lesion-absent PET images were reconstructed from clinical data, and lesion-present images were reconstructed with adding simulated lesion sinogram data. Lesion-present and lesion-absent PET image pairs were labeled by eight HOs consisting of four radiologists and four image scientists in a 2AFC detection task. In total, 2268 pairs of lesion-present and lesion-absent images were used for training, 324 pairs for validation, and 324 pairs for test. CNN DLMO, CNN-SwinT DLMO, CHO with internal noise, and non-prewhitening matched filter (NPWMF) were compared in the same train-test paradigm. For comparison, six quantitative metrics including prediction accuracy, mean squared errors (MSEs) and correlation coefficients, which measure how well a MO predicts HOs, were calculated in a 9-fold cross-validation experiment. In terms of the accuracy and MSE metrics, CNN DLMO and CNN-SwinT DLMO showed better performance than CHO and NPWMF, and CNN-SwinT DLMO showed the best performance among the MOs evaluated. DLMO can predict HOs more accurately than conventional MOs such as CHO in PET lesion detection. Combining SwinT and CNN encoders can improve the DLMO prediction performance compared to using CNN only.

Clinical Anatomy of the Lower Extremity Veins—Topography, Embryology, Anatomical Variability, and Undergraduate Educational Challenges

Veins of the lower extremity can be categorized into three hierarchically ordered groups: the epifascial, the interfascial, and the deep ones. In the past, the interfascial veins, e.g., the great saphenous vein, were categorized as superficial veins. But nowadays, experts recommend regarding these veins as a separate group because of their unique topography and clinical relevance. In order to better understand the venous anatomy of the lower limbs, which is highly variable, one should also comprehend their embryological development. Venous embryogenesis in the lower limb consists of three stages. During the first stage the primitive fibular vein is the main vein of the extremity. During the second stage it is replaced by the axial vein and finally by the femoral vein. In some adult individuals this embryonic or fetal venous anatomy is still present. Unfortunately, current anatomical textbooks and atlases, as well as traditional cadaver dissections, are not very useful regarding these issues. Therefore, undergraduate teaching of anatomy can be challenging. New educational tools, such as ultrasonography, seem indispensable to teach the anatomy of these veins properly.