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BackgroundThis study assesses the feasibility of real-time surgical navigation to plan and guide sequential steps during mandible reconstruction on a series of cadaveric specimens.MethodsAn image-guided surgical (IGS) system was designed including customized mandible and fibula fixation devices with navigation reference frames and an accompanied image-guided software. The mandibular and fibular segmental osteotomies were performed using the IGS in all five cadaveric patients. Procedural time and cephalometric measurements were recorded.ResultsFive real-time IGS mandibulectomy and fibular reconstruction were successfully performed. The mean Dice score and Hausdorff-95 distance between the planned and actual mandible reconstructions was 0.8 ± 0.08 and 7.29 ± 4.81 mm, respectively. Intercoronoid width, interangle width, and mandible projection differences were 1.15 ± 1.17 mm, 0.9 ± 0.56 mm, and 1.47 ± 1.62 mm, respectively.ConclusionThis study presents the first demonstration of a comprehensive image-guided workflow for mandibulectomy and fibular flap reconstruction on cadaveric specimens and resulted in adequate cephalometric accuracy.

Compositional changes can occur in the osteochondral junction (OCJ) during the early stages and progressive disease evolution of knee osteoarthritis (OA). However, conventional magnetic resonance imaging (MRI) sequences are not able to image these regions efficiently because of the OCJ region's rapid signal decay. The development of new sequences able to image and quantify OCJ region is therefore highly desirable. We developed a comprehensive ultrashort echo time (UTE) MRI protocol for quantitative assessment of OCJ region in the knee joint, including UTE variable flip angle technique for T1 mapping, UTE magnetization transfer (UTE-MT) modeling for macromolecular proton fraction (MMF) mapping, UTE adiabatic T1ρ (UTE-AdiabT1ρ) sequence for T1ρ mapping, and multi-echo UTE sequence for T2* mapping. B1 mapping based on the UTE actual flip angle technique was utilized for B1 correction in T1, MMF, and T1ρ measurements. Ten normal and one abnormal cadaveric human knee joints were scanned on a 3T clinical MRI scanner to investigate the feasibility of OCJ imaging using the proposed protocol. Volumetric T1, MMF, T1ρ, and T2* maps of the OCJ, as well as the superficial and full-thickness cartilage regions, were successfully produced using the quantitative UTE imaging protocol. Significantly lower T1, T1ρ, and T2* relaxation times were observed in the OCJ region compared with those observed in both the superficial and full-thickness cartilage regions, whereas MMF showed significantly higher values in the OCJ region. In addition, all four UTE biomarkers showed substantial differences in the OCJ region between normal and abnormal knees. These results indicate that the newly developed 3D quantitative UTE imaging techniques are feasible for T1, MMF, T1ρ, and T2* mapping of knee OCJ, representative of a promising approach for the evaluation of compositional changes in early knee OA.

The transverse sinus (TS) is often involved with pathology for structural reasons. The aim of this study was to improve understanding of the anatomy along the groove of the TS and sigmoid sinus (SS), to discuss the relationship between the bony features and pathologies affecting the TS. Seventy dry skulls (140 sides) were used for detailed observation of the TS and SS grooves using gross investigation coupled with transillumination. Bony features such as the mastoid foramen (MF), occipital foramen (OF), granular foveolae (GF), and absence of the TS groove were evaluated, and a classification based on numbers of findings was proposed. The most common internal groove finding was MF (79.3%), followed by absent TS groove (32.9%), and OF (14.3%). MF was statistically more frequent on the left side (91.4%) than the right (67.1%) (p = 0.036); OF was statistically more frequent on the right side (24.3%) than the left (4.3%) (p = 0.008). Absent TS groove was more prevalent on the left side (54.3%) than the right (11.4%) (p = 0.000). A bony prominence (BP) was identified in 15.7% (11 skulls) and there were significant differences from the controls. The type III class (three internal groove findings) was the most prevalent, followed by type II (two findings). The complex and integral role of the bony features described here, and their particularities in normal patients or in those with DVS pathologies, is not well understood.

BACKGROUND: Dark-field radiography imaging exploits the wave character of x-rays to measure small-angle scattering on material interfaces, providing structural information with low radiation exposure. We explored the potential of dark-field imaging of bone microstructure to improve the assessment of bone strength in osteoporosis. METHODS: We prospectively examined 14 osteoporotic/osteopenic and 21 non-osteoporotic/osteopenic human cadaveric vertebrae (L2-L4) with a clinical dark-field radiography system, micro-computed tomography (CT), and spectral CT. Dark-field images were obtained in both vertical and horizontal sample positions. Bone microstructural parameters (trabecular number, Tb.N; trabecular thickness, Tb.Th; bone volume fraction, BV/TV; degree of anisotropy, DA) were measured using standard ex vivo micro-CT, while hydroxyapatite density was measured using spectral CT. Correlations were assessed using Spearman rank correlation coefficients. RESULTS: The measured dark-field signal was lower in osteoporotic/osteopenic vertebrae (vertical position, 0.23 ± 0.05 versus 0.29 ± 0.04, p

INTRODUCTION: Adjunctive suture augmentation of patellar plate fixation has yet to be investigated. Our biomechanical study sought to evaluate whether suture augmentation improves dorsal patellar locking plate fixation. Our hypothesis was that suture augmentation would improve fixation of this construct. METHODS: A transverse patella fracture in six matched cadaveric pairs was stabilized using a patellar locking plate with or without suture augmentation. Specimens were tested at 60° knee flexion with load placed through quadriceps. Cyclic loading followed by load to failure was done. Stiffness, deformation at peak, and nonrecoverable deformation were calculated. RESULTS: During cyclic loading, suture augmentation demonstrated a higher average stiffness throughout all loads. At the final cycle, deformation was markedly higher without suture augmentation. Average load to failure was higher with suture augmentation. Maximum load to failure occurred at 2500 N in both groups. CONCLUSION: Suture augmentation in a transverse patellar fracture model improved dorsal plate fixation, leading to less fracture displacement at the final load. Although suture augmentation demonstrated higher stiffness and lower deformation, these trends were not statistically significant. In both groups, plate fixation sustained very high loads, which reflects the fixation strength of the dorsal locking plate and screw construct in this fracture model.

BackgroundThe appropriate amount of cementation at the time of reverse total shoulder arthroplasty with significant proximal bone loss or resection is unknown. Extensive cementation of a humeral prosthesis makes eventual revision arthroplasty more challenging, increasing the risk of periprosthetic fracture. We analyzed the degree of subsidence and torque tolerance of humeral components undergoing standard cementation technique vs. our reduced polymethyl methacrylate (PMMA) protocol. Reduced cementation may provide sufficient biomechanical stability to resist physiologically relevant loads, while still permitting a clinically attainable torque for debonding the prosthesis.MethodsA total of 12 cadaveric humeri (6 matched pairs) underwent resection of 5 cm of bone distal to the greater tuberosity. Each pair of humeri underwent standard humeral arthroplasty preparation followed by either cementation using a 1.5-cm PMMA sphere at a location 3 cm inferior to the porous coating or standard full stem cementation. A 6-degree-of-freedom robot was used to perform all testing. Each humeral sample underwent 200 cycles of abduction, adduction, and forward elevation while being subjected to a physiologic compression force. Next, the samples were fixed in place and subjected to an increasing torque until implant-cement separation or failure occurred. Paired t tests were used to compare mean implant subsidence vs. a predetermined 5-mm threshold, as well as removal torque in matched samples.ResultsFully and partially cemented implants subsided 0.49 mm (95% CI 0.23-0.76 mm) and 1.85 mm (95% CI 0.41-3.29 mm), respectively, which were significantly less than the predetermined 5-mm threshold (P

Purpose: In this study, it was aimed to examine the relationship between the profunda brachii artery and the radial nerve at the entrance to and within the radial groove considering no comparable study was found in the literature. Method: Dissection was performed in 44 upper extremities (21 right and 23 left) of 24 fixed cadavers used for medical education at Istanbul University, Istanbul Medical Faculty, Department of Anatomy. Results: Profunda brachii artery was found to be a single artery in 39 extremities and a double artery in 5 extremities. In 27 cases with single PBA, the nerve was located superolateral to the PBA (Type A), and in 8 cases the nerve was located inferomedial to the PBA (Type B). In all 5 extremities with double profunda brachii artery, the proximal branch was superolateral (Type A) and the distal branch was inferomedial (Type B). Conclusions: This research will support surgeons understanding how to better anatomically and radiologically treat humeral fractures and lateral arm flap applications. [ABSTRACT FROM AUTHOR]

Neuroendoscopy can be learnt by assisting or doing live human surgery, cadaver dissection with or without augmented pulsatile vessel and cerebrospinal fluid (CSF) perfusion, and practicing on live animal, dead animal model, synthetic models, three-dimensional printing model with or without augmentation with animal, cadaver tissue, pulsatile vessel and reconstructed CSF model, virtual reality (VR) simulator, and hybrid simulators (combined physical model and VR model). Neurosurgery skill laboratory with basic and advanced learning should be there in all teaching hospitals. Skills can be transferred from simulation model or VR to cadaver to live surgery. Staged learning (first with simple model to learn basic endoscopic technique, then animal model, and then augmented cadavers) is the preferred method of learning. Although most surveys favor live surgery and practice on animal models and cadavers as the most preferred training model now, in future VR may also become a favored method of learning. This article is based on our experience in over 10,000 neuroendoscopic surgeries, and feedback from over 950 neuroendoscopic fellows or consultants who attended workshops conducted every 6 monthly since 2010. A literature search was done on PubMed and Google Scholar using (neuroendoscopy) AND (learning), and (neuroendoscopy) AND (training), which resulted in 121 and 213 results, respectively. Out of them, 77 articles were finally selected for this article. Most of the training programs typically focus on microneurosurgical training. There is lack of learning facilities for neuroendoscopy in most centers. Learning of neuroendoscopy differs greatly from microneurosurgery; switching from microneurosurgery to neuroendoscopy can be challenging. Postgraduate training centers should have well-equipped neuroendoscopy skill laboratory and the surgical educational curriculum should include neuroendoscopy training. Learning endoscopy is about taking advantages of the technique and overcoming the limitations of endoscopy by continuous training. [ABSTRACT FROM AUTHOR]

Purpose: The anatomy of the extraocular rectus muscle insertions is clinically relevant in the field of ophthalmology. This descriptive cadaveric study determines the relative degree orientation of the superior, lateral, and inferior rectus muscles with respect to the medial rectus and investigates the distances between the rectus muscle insertions. Method: Thirty cadavers (50% female, mean age = 81.86 years, SD 12.16) were included for a total of 60 eyes. For each eye, a lateral canthotomy and cantholysis were performed followed by a peritomy. Muscle hooks were then used to access and isolate the rectus muscles. The degree orientation was determined by marking the muscle midpoints at insertion, using the center of the cornea as the vertex, and measuring the angle with the Angle Meter 360 application (© Alexey Kozlov) (Figure 1). The distances between rectus muscles were measured from the same muscle midpoints using calipers. Results: The degree orientations with respect to the medial rectus are displayed in Figure 2 and were as follows: superior rectus (mean = 93.14, SD = 3.04, min. 82.3, max. 100.3), lateral rectus (mean = 180.21, SD = 5.65, min. 170.5, max. 190.6), and inferior rectus (mean = 90.57, SD = 4.47, min. 84.0, max. 98.9). The distances (measured in mm) between rectus muscle midpoints at insertion included medial rectus to inferior rectus (mean = 13.64, SD = 0.54), inferior rectus to lateral rectus (mean = 13.79, SD = 0.75), lateral rectus to superior rectus (mean = 13.54, SD = 0.63), and superior rectus to medial rectus (mean = 13.83, SD = 0.75). The relative distances between the midpoints of the extraocular muscles observed in males versus females showed statistically significant differences in medial rectus to inferior rectus (13.8 vs. 13.5, p =.01), inferior rectus to lateral rectus (14.1 vs. 13.5, p =.03), and superior rectus to medial rectus (14.0 vs. 13.5, p =.04), respectively (Table 1). Conclusion: This is an important study of the extraocular muscle degree orientation performed with an innovative measuring approach. The degree orientation of the insertions relative to the medial rectus may have surgical application in the field of ophthalmology. [ABSTRACT FROM AUTHOR]

Background: There is no consensus as to the best technique for percutaneous trigger finger release. Methods: This assessor-blinded study compared three ultrasound-guided percutaneous trigger finger release techniques using a needle (N), a needle-knife (NK), and a specially designed knife (K). Three physicians simulated A1 pulley release surgery on 56 fingers of 14 fresh-frozen hand cadaver body donors. Both the physicians and the fingers included were randomly selected. Results: The results of repeated-measures ANOVA revealed significantly longer cuts for the NK and K techniques, than for the N technique, both absolute (mean ± SD) (NK = 5.55 ± 3.07 mm, K = 6.29 ± 4.07 mm, and N = 2.02 ± 3.46 mm; N vs. NK p = 0.015, N vs. K p = 0.002, and NK vs. K p = 1.000), and cut percentage in relation to the total pulley length (NK = 51.61 ± 28.34%, K = 54.63 ± 33.72% and N = 18.24 ± 31.09%; N vs. NK p = 0.008, N vs. K p = 0.003, and NK vs. K p = 1.000). No neurovascular bundle injuries were found upon dissection. The overall complication rate was 11%, with no significant differences among the three techniques. Only one major tendon injury occurred in the NK group. Conclusions: In this cadaveric study, the NK and K techniques were more effective at releasing the A1 pulley than the N technique. All three techniques have emerged as equally safe. [ABSTRACT FROM AUTHOR]

Purpose: The main objective was to study the anatomy of the adductor longus by ultrasound and cadaveric dissection, correlate the findings with the different approaches described, and evaluate the feasibility of defining a "safe window" for interventional musculoskeletal procedures. Methods: The anatomical study was performed on six cadaveric pieces, while ultrasound evaluations were performed on both lower limbs of 26 subjects (n = 52). Ultrasound variables included the number of saphenous veins, the location of the saphenous vein in relation to the proximal myotendinous junction, the number of vessels within or superficial to the adductor longus, and the distance between the dermis and the inferior border of the adductor longus to the anterior branch of the obturator nerve. Results: Key anatomic risk factors identified in cadavers included the great saphenous vein, the anterior branch of the obturator nerve, and the vascular network traversing the adductor longus. Ultrasound findings revealed that 91.4% of cases had at least one vessel at the proximal myotendinous junction in the cross-sectional area, almost 60% showed two to five vessels within the thickness of the muscle, and the anterior branch of the obturator nerve was located at a mean depth of 3.63–3.93 cm. Conclusions: It was not possible to define a "safe" approach area without the risk of damaging any neurovascular bundle due to the high anatomical variability both in number and in the route of these along the adductor longus. Therefore, the use of ultrasound to guide any interventional musculoskeletal procedure is highly recommended. [ABSTRACT FROM AUTHOR]

Background: While MRI is the gold standard for meniscal assessment, its cost and accessibility limitations have led to growing interest in ultrasound, though its validity for quantifying meniscal tissue remains unclear. To validate the use of ultrasound in quantifying meniscal tissue across the anterior, middle, and posterior regions of both menisci (medial and lateral) in longitudinal and transverse planes by comparison with cadaveric dissection. Methods: A cross-sectional study was conducted on ten cryopreserved anatomical donors, obtaining a total of 120 ultrasound scans from the different meniscal regions. Following ultrasound imaging, cadaveric dissection was performed to facilitate photometric measurements, thereby enabling validation of the ultrasound findings. The intra-examiner reliability of the ultrasound measurements was also assessed. Results: The intra-examiner reliability of ultrasound measurements ranged from moderate to excellent. A strong and statistically significant positive correlation was observed between ultrasound and photometric measurements across all meniscal regions (r > 0.821; p < 0.05). In the medial meniscus, ultrasound visualized 99.1% of the anterior region (8.71 mm with ultrasound; 8.64 mm with photometry), 96.3% of the middle region (9.09 mm with ultrasound; 9.39 mm with photometry), and 98.5% of the posterior region (10.54 mm with ultrasound; 10.61 mm with photometry). In the lateral meniscus, ultrasound visualized 107.1% of the anterior region, 105.1% of the middle region, and 97.8% of the posterior region. The observed excess in tissue visualization in some regions likely reflects the inclusion of adjacent connective tissue, indistinguishable from meniscal tissue on ultrasound. Conclusions: Ultrasound is a valid and reliable modality for visualizing most meniscal tissue across regions, with a measurement discrepancy under 0.7 mm compared to anatomical dissection. However, caution is advised as adjacent connective tissue may sometimes be misidentified as meniscal tissue during evaluations. [ABSTRACT FROM AUTHOR]

The emergence of SARS-CoV-2, responsible for the COVID-19 pandemic, has prompted extensive research into its transmission dynamics; yet, a critical aspect that remains underexplored is the post-mortem infectivity of the virus within cadaveric tissues. Understanding the mechanisms by which SARS-CoV-2 maintains infectivity after death is essential, as it raises significant concerns regarding public health and forensic practices. Research indicates that the virus can persist in various tissues, including lung, liver, and kidney tissues, with studies showing that factors such as the time elapsed since death, the presence of underlying health conditions, and environmental conditions at the time of death can influence the level of infectivity in deceased individuals. These findings are not only crucial for establishing safety protocols for forensic investigators who handle cadavers but also for informing public health guidelines that govern the management of bodies during and after outbreaks. As we investigate the implications of post-mortem SARS-CoV-2 infectivity, it becomes imperative to establish comprehensive protocols to mitigate risks associated with the handling and disposal of infected bodies, thereby protecting public health and ensuring the safety of those working in forensic environments. This paper aims to elucidate the mechanisms of infectivity in cadaveric tissues, explore the persistence of the virus in various tissue types, and assess the broader implications for public health and forensic investigations, ultimately contributing to a safer approach in dealing with COVID-19-related fatalities. [ABSTRACT FROM AUTHOR]

The skills necessary to perform diagnostic perineural anesthesia in equids belongs to one of the Day One Competences of a veterinarian, so every veterinary graduate should be able to perform them correctly. For logistical, hygienic and ethical reasons, practical exercises on cadaver limbs are not accessible to all students. Two equine distal limb simulators were developed and evaluated as an additional instructional tool to train the required skills. Both simulators were designed and built with an integrated success control, with Simulator I (S1) designed to be a simplified anatomical model and Simulator II (S2), a more realistic model. The simulators were tested by 68 students in the 5th year who were divided into two groups. Thirty-four students received a training session using the simplified anatomical model (S1) and the other 34 students one on cadaver limbs, the usual instructional tool. The practical learning success of both groups was validated using S2. Additionally, data on self-efficacy were collected. The results show that the two groups did not differ significantly in their practical learning success, whereas self-efficacy of both groups increased significantly after the sessions. An evaluation performed by 7 veterinarians and 49 students of the 5th year indicate that the simulators are suitable for teaching perineural anesthesia in the equine distal limb. However, S2 could be more realistic. The simulators will be used as a supplement to exercises on cadaver limbs to enable all students to practice perineural anesthesia. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to define a new surgical method using a neurotized platysma free flap to provide dynamic reanimation, enhanced functional recovery, and low morbidity for blepharoptosis repair. Methods: Ten hemifaces and neck halves of five formalin-fixed cadavers were included in the study. The origin of the neurovascular structures of the pedicle was identified at the submandibular triangle. A 5 × 3 cm platysma flap was dissected. For the recipient side, the main donor vascular structures were observed at the frontal part of the temporal region. The diameters of the donor structures were measured with a digital Vernier caliper. The statistical analysis of the study was performed with Jamovi statistical software version 2.3.36. P < 0.05 was accepted as a statistically significant value. Results: At the donor region, the pedicle included branches of the cervical branch of the facial nerve and the facial artery in all specimens. However, the venous graft pedicle origin could be either the facial vein or the lingual vein. At the recipient region, the mean diameters of the most anterior nerves, arteries, and veins were 1, 2.03, and 2.37 mm respectively. In a side comparison of pedicle variables, only pedicle artery diameter and lateral palpebral commissure-anterior superior point of auricula distance had statistically significant differences between hemifaces. Conclusion: A 5 × 3 cm size platysma flap located in the submandibular trigone would be a good choice for functional blepharoptosis surgery. The thin structure and the appropriate neurovascular pedicle structure should enable performing a successful flap transfer. [ABSTRACT FROM AUTHOR]

Background: The radial nerve (RN) is a peripheral nerve that originates from the posterior bundle of the brachial plexus and carries C5-Th1 fibres. In the cubital fossa, the radial nerve divides into a superficial branch of the radial nerve (SBRN) and a deep branch of the radial nerve (DBRN). Next, the DBRN enters under the arcade of Frohse (AF) and changes its name to posterior interosseous nerve of antebrachii (PIN). The AF, first described in 1908 by Frohs and Frankel, is the superior proximal part of the supinator muscle, which can be tendinous or membranous. Materials and methods: Eight dissected upper limbs were examined to measure the distances and characteristics of the RN, DBRN, SBRN and AF, using a precise electronic caliper. Results: The average distance from the point of branching of the RN into its terminal branches to the AF was 54.64 mm. In half of the cases, the DBRN divided before entering the AF. The average distance from the point of branching of the DBRN to the AF in these cases was 13.88 mm. The average width of the AF was 8.60 mm. Five tendinous AF and three membranous AF were identified. Conclusions: A thorough understanding of the anatomy of the radial nerve and its branches in the cubital fossa, as well as the AF, is important for the proper understanding of anatomy, and may also contribute to the reduction of surgical complications during procedures in this area. [ABSTRACT FROM AUTHOR]

Purpose: The exit points of the supraorbital nerve and its branches hold significant importance in various medical procedures, including supraorbital endoscopic surgeries, forehead–facial aesthetic plastic surgeries, medical aesthetic applications and maxillofacial surgeries. Therefore, the primary objective of the present study was to precisely define the dimension, location and clinical significance of the supraorbital foramen/notch. By doing so, we aimed to enhance our understanding of this anatomical structure and its implications for surgical and aesthetic interventions in the supraorbital region. Methods: For our study, we conducted anatomical dissections and bone measurements to assess the significance of anatomical variations of the supraorbital foramen/notch. We utilized a sample consisting of 28 cadavers and 38 skulls. The supraorbital foramen/notch was bilaterally analyzed in all 28 cadavers and 38 dry bones. We morphometrically analyzed the distance between the supraorbital foramen/notch and various anatomical landmarks, including the nasion, supraorbital margin, infraorbital margin, temporal crest, glabella, frontal cavity and midline of the face. Additionally, we measured the distance between the supraorbital foramen/notches and the frontal foramen/notches, and the width of the supraorbital foramen/notch and the distance between both supraorbital foramina/notches. Results: There are 32 (57.14%) supraorbital foramina, and the remaining are 24 (42.86%) supraorbital notches in cadavers and there are 36 (47.37%) supraorbital foramina, and the remaining are 40 (52.63%) supraorbital notches in skulls. We observed consistency in the dimension and location values of anatomical measurement parameters between cadavers and dry skulls on both right and left sides, with the exception of the parameter "distance from temporal crest" (p=0.042). Furthermore, our correlation analysis revealed a significant positive relationship between the right and left sides across all parameters, except for the following instances: in dry skulls, "distance from supraorbital margin" and in cadaver parameters, "distance from temporal crest, " "distance from frontal cavity" and "width." Conclusion: In our study, we observed that the distributions of supraorbital foramina and notches were nearly similar. Furthermore, our findings indicated comparable measurements between the right and left sides in both cadavers and skulls. These results suggest a degree of consistency in supraorbital anatomy within our study sample, regardless of the specimen type (cadavers or skulls) or laterality (right or left side). No Level Assigned: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 [ABSTRACT FROM AUTHOR]

BackgroundThe calcaneal enthesis, an osseous footprint where the Achilles tendon seamlessly integrates with the bone, represents a complex interface crucial for effective force transmission. Bone adapts to mechanical stress and remodels based on the applied internal and external forces. This study explores the relationship between the elasticity of the Achilles tendon enthesis and the bone microstructure in the calcaneal crescent.MethodsIn total, 19 calcaneal-enthesis sections, harvested from 10 fresh-frozen human cadaveric foot-ankle specimens (73.8 ± 6.0 years old, seven female), were used in this study. Indentation tests were performed at the enthesis region, and Hayes' elastic modulus was calculated for each specimen. Micro-CT scanning was performed at 50-micron voxel size to assess trabecular bone microstructure within six regions of interest (ROIs) and the cortical bone thickness along the calcaneal crescent.ResultsSignificant Spearman correlations were observed between the enthesis elastic modulus and trabecular bone thickness in the distal entheseal (ROI 3) and proximal plantar (ROI 4) regions (R = 0.786 and 0.518, respectively).ConclusionThis study highlights the potential impacts of Achilles tendon enthesis on calcaneal bone microstructure, which was pronounced in the distal calcaneal enthesis, suggesting regional differences in load transfer mechanism that require further investigation.

INTRODUCTION: Patients suffering from trauma are at risk of death from uncontrolled external bleeding, therefore witnesses to the incident and emergency medical services should promptly implement appropriate procedures, which requires prior training. The purpose of this study is to comparatively analyze the didactic effectiveness resulting from the use of cadavers – human-based unfixed preparations, and training devices, during practice-based teaching of medical students on how to stop external hemorrhage. MATERIALS AND METHODS: Fifty-four medical students participated in the study. At the initial stage, training was provided including procedures for stopping external hemorrhages using hand maneuvers, tourniquets, and hemostatic dressings. Randomization was performed by selecting a study group (procedures performed on human unfixed specimens) and a control group (procedures performed on a training model). During the practical test, the time to perform the procedure until the hemorrhage was effectively stopped was evaluated. The students were also asked to perform a self-assessment of their skills, as well as to indicate their level of satisfaction with the training. Statistical analysis allowed to obtain correlations of variables, taking age, sex, height, body mass and hand sizes of the subjects into account. RESULTS: The study group consisted of 35 women (64.81%) and 19 men (35.19%). Intergroup comparisons confirmed the absence of significant differences between groups in Mann-Whitney U tests for unrelated variables for the criterion of sex (p=0.403), age (p=0.081), height (p=0.472), body mass (p=0.883), hand width (p=0.653) and hand length (p=0.355). Group A performed the procedures on training models, while Group B performed the procedures on appropriately prepared cadavers. Direct manual compression was performed in an average of 2.85 seconds (group A) and 5.23 seconds (group B), wound packing in an average of 42.48 seconds (group A) and 50.97 seconds (group B), passing a tourniquet fastened into a loop in an average of 27.66 seconds (group A) and 26.01 seconds (group B), and an unfastened tourniquet over bleeding site in an average of 27.70 seconds (group A) and 29.14 seconds (group B). The manual wound compression procedure was performed significantly longer on the cadaver (p=0.005) than on the training model. The level of satisfaction and self-assessment after the training increased comparably in both groups. CONCLUSIONS: Unfixed human-body-based preparations constitute an important part of medical student education. Simulations of external hemorrhage stopping allowed noticing prolonged procedure performance time in the case of cadaver-based exercises, especially regarding the procedure for manual wound compression. The results suggest that selected rescue procedures are more difficult to perform on human specimens, compared to training models, therefore cadaver-based training may prove more effective

Background: It is very well known that the supraclavicular nerve (SCN) which occupies the inferior part of the superficial cervical plexus basically originates from the ventral rami of C2–C4, then travels caudally into the investing layer of the deep cervical fascia (IL-DCF) alternatively termed the “prevertebral fascia.” Methods: This cadaveric study (a total of 6 soft-embalmed cadavers and bilateral dissections, i.e. 12 specimens) intended to ascertain the location of SCN within the layers of the IL-DCF. We hypothesized that ultrasonography identification of SCN within the IL-DCF and needle tip positioned between the layers of IL-DCF provide an alternative site for the blockade of the SCN. Results: After dissection, we described a compact double-layered IL-DCF hosting the SCNs and a specific topographic arrangement at the C4 root with SCN lateral and C4 branches of the phrenic nerve medial to the C4. Conclusion: We recommend another alternative site for the SCN block at a site in the compact double layer of IL-DCF. We conclude that a caudal site at the exit of SCN from the IL-DCF would be appropriate to perform the intervention.

Abstract The high incidence of deep vein thrombosis (DVT) in evacuees has been recognized since the 2004 Niigata-Chuetsu Earthquake in Japan. We hypothesized that the number and location of communicating branches of the soleal veins might influence thrombus development and that the median septum of the soleus muscle influences the venous network of the soleal veins. This study aimed to investigate how the network of soleal veins varies with the shape and thickness of the median septum and to elucidate factors predisposing soleal veins to DVT. The lower legs of 30 sides from 15 formalin-preserved cadavers were observed. The central soleal vein, the predilection site for thrombus among the six veins within the soleus muscle, divides into three branches: medial, central, and lateral. The soleus muscle has a unique architecture with converging muscle fibers on the anterior surface of the median septum. We examined the positional relationship between the central soleal vein and the median septum. The median septum morphology was either straight (14 sides, 46.7%) or curved (16 sides, 53.3%). The number of communicating branches was significantly higher in the curved type. The curved type also had a communicating vein penetrating the median septum, with the central branch passing deeper than in the straight type. The median septum could restrict the enlargement of communicating branches, causing thrombosis through disturbance of venous blood flow. Future research will clarify the median septum’s influence on the soleal vein, potentially identifying soleus muscles at high risk of developing DVT.

Background: The aim of this systematic review was to investigate the available literature on the biomechanical characteristics of the acromioclavicular (AC) joint to identify trends in translational parameters and contributions of the various ligamentous structures supporting the joint. Methods: A comprehensive literature search was conducted in the Web of Science, Scopus, and PubMed databases until October 2023 to identify articles reporting on the biomechanical characteristics of the AC joint. Non cadaveric or projects involving reconstruction were excluded. Consistent parameters evaluated were anterior, posterior, superior, and inferior translation. The data were extracted from the included articles and summarized. Results: 11 biomechanical papers were reviewed from six different countries — United States (n = 6), France (n = 1), Austria (n = 1), Thailand (n = 1), United Kingdom (n = 1), and Japan (n = 1). The total number of specimens included across the reviewed papers was 141. All 11 papers reported the data on an intact model (coracoclavicular and AC ligaments intact). Seven papers assessed the translational results of the AC sectioned condition, finding a greater increase in anterior-posterior (AP) laxity relative to SI. 3 papers evaluated coracoclavicular ligament sectioning, finding increased superior-inferior laxity relative to AP. Only one study involved ligament sectioning isolating the anterior-inferior bundle of the AC joint. Conclusion: This review highlights the key AP and superior-inferior constraints of both the intact and ligament sectioned AC joint. The inconsistency of AC joint testing parameters and the lack of thorough translation studies indicate a necessity for increased attention in the overall assessment of shoulder stability to close the gap in the foundational biomechanical research.

Abstract Background Dark-field radiography imaging exploits the wave character of x-rays to measure small-angle scattering on material interfaces, providing structural information with low radiation exposure. We explored the potential of dark-field imaging of bone microstructure to improve the assessment of bone strength in osteoporosis. Methods We prospectively examined 14 osteoporotic/osteopenic and 21 non-osteoporotic/osteopenic human cadaveric vertebrae (L2–L4) with a clinical dark-field radiography system, micro-computed tomography (CT), and spectral CT. Dark-field images were obtained in both vertical and horizontal sample positions. Bone microstructural parameters (trabecular number, Tb.N; trabecular thickness, Tb.Th; bone volume fraction, BV/TV; degree of anisotropy, DA) were measured using standard ex vivo micro-CT, while hydroxyapatite density was measured using spectral CT. Correlations were assessed using Spearman rank correlation coefficients. Results The measured dark-field signal was lower in osteoporotic/osteopenic vertebrae (vertical position, 0.23 ± 0.05 versus 0.29 ± 0.04, p

Abstract Background Understanding human anatomy is fundamental to building medical competencies. This study explored the diverse perceptions of medical students in Saudi Arabia and Egypt concerning virtual dissection applications. Methods Students from different Saudi and Egyptian governmental universities were invited. The online questionnaire covered the sociodemographic characteristics, students’ perception of the advantages of virtual anatomy applications, satisfaction with their efficiency, and their recommendation to use them. Comparisons were performed in country-wise and then university-wise patterns. Significance was considered with a P

Objective: The purpose of this cadaveric investigation was to provide a detailed morphologic description of the proximal gastrocnemius within the popliteal region of the knee and test the hypothesis that the gastrocnemius is anatomically positioned to function as an antagonist to the anterior cruciate ligament (ACL) of the knee. Methods: Twenty-two lower limbs from 11 embalmed cadavers underwent detailed dissection and anatomical analysis. Results: The results indicate that 63.3 ± 5.8% of the popliteal region is comprised of the hamstrings and the gastrocnemius, whereas 36.8 ± 5.7% is occupied by free space (fossa). Within the popliteal region, the gastrocnemius had a length crossing above the knee joint line of 5.4 ± 1.2 cm, which would likely result in a posterior pull on the femur during muscular contraction. Data provide an in-depth description of length and width morphology of the gastrocnemius and provide a detailed comparison between the medial and lateral heads of the muscle. Our results agree with earlier reports in the literature which suggest that the medial head is significantly longer and wider than the lateral head of the gastrocnemius. The medial head length was 23 ± 3.4 cm, compared to a lateral head length of 20.5 ± 2.9 cm. The medial head maximum width was 5.5 ± 1.6 cm, compared to a lateral head maximum width of 4.2 ± 1.1 cm. Conclusion: This research expands on past descriptions of the femoral origin of the gastrocnemius muscle’s medial head and confirms past descriptions of the lateral head origin on the femur. Our data clearly illustrate that the femoral attachment of the medial head of the gastrocnemius was much different (or more complex) than previously described and that it wraps around the posterior side of the medial femoral condyle and attaches more anteriorly. Further research should be directed at exploring the functional significance (if any) of these differences and examining the effect they may have on ACL function and knee joint kinematics.

Abstract Background Distal radioulnar joint (DRUJ) instability is a common post-traumatic complication, often leading to chronic pain and dysfunction. Current reconstructive techniques, such as the single suture button construct, offer suboptimal stabilization in certain motions. This study aimed to evaluate whether a double suture button construct provides greater stability than the single construct in a cadaver model of DRUJ instability. We hypothesized that the double suture button construct would more effectively minimize dorsal translation of the radius relative to the ulna. Methods We used nine freshly frozen human cadaver upper extremities, destabilized the DRUJ, and then reconstructed the joint using three different suture button constructs: single transverse, double (transverse + oblique), and single oblique. The specimens were secured in a custom-designed testing apparatus to measure dorsal translation of the radius. The study proceeded in five stages: stable DRUJ, unstable DRUJ, and reconstruction using a single transverse, double (transverse + oblique), and single oblique suture button construct. Dorsal translation was measured at neutral, 45° pronation, and 45° supination. Statistical comparisons of mean values were conducted for each stage. Results Reconstruction with the transverse, transverse plus oblique, and oblique suture button constructs resulted in statistically significant reductions in dorsal translation compared to the unstable DRUJ (p

Background: Dry needling (DN) has emerged as a popular therapeutic intervention for managing musculoskeletal pain. While major adverse events are generally rare, those that have been reported in vulnerable areas such as the spine and thorax can be serious and warrant further investigation regarding safe techniques in and around these areas. Purpose: The purpose of this study was to reproduce the methods employed by Williams et al. but with an inferior-medial multifidus DN technique to determine if a dry needle can penetrate the ligamentum flavum (LF) and breach the spinal canal at the thoracolumbar junction. Study Design: Descriptive Cadaveric study. Methods: The procedure was performed on a cadaver in the prone position. The needle was advanced under ultrasound guidance to determine if a 0.30 x 40 mm dry needle inserted lateral to the spinous process of T12 and directed inferior-medially could penetrate the LF and enter the spinal canal. Results: A 0.30 x 40 mm dry needle inserted 1.9 cm lateral to the spinous process of T12 was able to traverse the space between the vertebral laminae of T12 and L1, penetrate the LF, and enter the spinal canal with an inferior-medial needle angulation of 33-degrees medial and 18-degrees inferior. Conclusion: The results of this study demonstrate the feasibility of a dry needle entering the spinal canal at the thoracolumbar junction using an inferior-medial technique. These findings support the potential role of ultrasound guidance in the training and clinical practice of DN, especially in regions where safety issues have been documented. Level of Evidence: Level IV. [ABSTRACT FROM AUTHOR]

Objectives The lateral supraorbital (LSO) approach is a less-invasive alternative to the pterional craniotomy that provides rapid transsylvian access. Establishing familiarity with the LSO technique and its features as compared with other anterolateral approaches is an important component of advanced skull base training. We present a step-by-step demonstration of the LSO approach using cadaveric dissection in a manner that is digestible for trainees at various levels. Design This is anatomic step-by-step dissection and representative case series. Setting This study was carried out in the cadaveric dissection laboratory. Participants A formalin-fixed, latex-injected cadaveric head specimen was dissected under microscopic magnification by a neurosurgery resident under faculty supervision. Following dissection, representative case applications were reviewed. Main Outcome Measures Dissection and case illustration were the main outcome measures. Results A single-layer myocutaneous flap is developed, and a single-burr-hole technique is used, followed by extensive drilling of the sphenoid wing. The dura is opened in a C-shaped fashion centered on the Sylvian fissure, exposing the inferior frontal and superior temporal lobes. Labeled photographs of dissections with pertinent anatomical structures are presented. Three case examples illustrating the versatility of the LSO approach, including the resection of a large pituitary adenoma, an inferior frontal melanoma metastasis presenting to the Sylvian surface, and a frontoinsular low-grade glioma, are reviewed. Conclusion As compared with the pterional craniotomy, the LSO approach involves a shorter incision, smaller craniotomy, and faster exposure; it can be conveniently tailored to various indications. Understanding the step-by-step dissection and indications of the LSO approach is of paramount importance to neurosurgery trainees. [ABSTRACT FROM AUTHOR]

INTRODUCTION: Patients suffering from trauma are at risk of death from uncontrolled external bleeding, therefore witnesses to the incident and emergency medical services should promptly implement appropriate procedures, which requires prior training. The purpose of this study is to comparatively analyze the didactic effectiveness resulting from the use of cadavers -- human-based unfixed preparations, and training devices, during practice-based teaching of medical students on how to stop external hemorrhage. MATERIAL AND METHODS: Fifty-four medical students participated in the study. At the initial stage, training was provided including procedures for stopping external hemorrhages using hand maneuvers, tourniquets, and hemostatic dressings. Randomization was performed by selecting a study group (procedures performed on human unfixed specimens) and a control group (procedures performed on a training model). During the practical test, the time to perform the procedure until the hemorrhage was effectively stopped was evaluated. The students were also asked to perform a self-assessment of their skills, as well as to indicate their level of satisfaction with the training. Statistical analysis allowed to obtain correlations of variables, taking age, sex, height, body mass and hand sizes of the subjects into account. RESULTS: The study group consisted of 35 women (64.81%) and 19 men (35.19%). Intergroup comparisons confirmed the absence of significant differences between groups in Mann-Whitney U tests for unrelated variables for the criterion of sex (p=0.403), age (p=0.081), height (p=0.472), body mass (p=0.883), hand width (p=0.653) and hand length (p=0.355). Group A performed the procedures on training models, while Group B performed the procedures on appropriately prepared cadavers. Direct manual compression was performed in an average of 2.85 seconds (group A) and 5.23 seconds (group B), wound packing in an average of 42.48 seconds (group A) and 50.97 seconds (group B), passing a tourniquet fastened into a loop in an average of 27.66 seconds (group A) and 26.01 seconds (group B), and an unfastened tourniquet over bleeding site in an average of 27.70 seconds (group A) and 29.14 seconds (group B). The manual wound compression procedure was performed significantly longer on the cadaver (p=0.005) than on the training model. The level of satisfaction and self-assessment after the training increased comparably in both groups. CONCLUSIONS: Unfixed human-body-based preparations constitute an important part of medical student education. Simulations of external hemorrhage stopping allowed noticing prolonged procedure performance time in the case of cadaver-based exercises, especially regarding the procedure for manual wound compression. The results suggest that selected rescue procedures are more difficult to perform on human specimens, compared to training models, therefore cadaver-based training may prove more effective. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this cadaveric investigation was to provide a detailed morphologic description of the proximal gastrocnemius within the popliteal region of the knee and test the hypothesis that the gastrocnemius is anatomically positioned to function as an antagonist to the anterior cruciate ligament (ACL) of the knee. Methods: Twenty-two lower limbs from 11 embalmed cadavers underwent detailed dissection and anatomical analysis. Results: The results indicate that 63.3 ± 5.8% of the popliteal region is comprised of the hamstrings and the gastrocnemius, whereas 36.8 ± 5.7% is occupied by free space (fossa). Within the popliteal region, the gastrocnemius had a length crossing above the knee joint line of 5.4 ± 1.2 cm, which would likely result in a posterior pull on the femur during muscular contraction. Data provide an in-depth description of length and width morphology of the gastrocnemius and provide a detailed comparison between the medial and lateral heads of the muscle. Our results agree with earlier reports in the literature which suggest that the medial head is significantly longer and wider than the lateral head of the gastrocnemius. The medial head length was 23 ± 3.4 cm, compared to a lateral head length of 20.5 ± 2.9 cm. The medial head maximum width was 5.5 ± 1.6 cm, compared to a lateral head maximum width of 4.2 ± 1.1 cm. Conclusion: This research expands on past descriptions of the femoral origin of the gastrocnemius muscle's medial head and confirms past descriptions of the lateral head origin on the femur. Our data clearly illustrate that the femoral attachment of the medial head of the gastrocnemius was much different (or more complex) than previously described and that it wraps around the posterior side of the medial femoral condyle and attaches more anteriorly. Further research should be directed at exploring the functional significance (if any) of these differences and examining the effect they may have on ACL function and knee joint kinematics. [ABSTRACT FROM AUTHOR]

The high incidence of deep vein thrombosis (DVT) in evacuees has been recognized since the 2004 Niigata-Chuetsu Earthquake in Japan. We hypothesized that the number and location of communicating branches of the soleal veins might influence thrombus development and that the median septum of the soleus muscle influences the venous network of the soleal veins. This study aimed to investigate how the network of soleal veins varies with the shape and thickness of the median septum and to elucidate factors predisposing soleal veins to DVT. The lower legs of 30 sides from 15 formalin-preserved cadavers were observed. The central soleal vein, the predilection site for thrombus among the six veins within the soleus muscle, divides into three branches: medial, central, and lateral. The soleus muscle has a unique architecture with converging muscle fibers on the anterior surface of the median septum. We examined the positional relationship between the central soleal vein and the median septum. The median septum morphology was either straight (14 sides, 46.7%) or curved (16 sides, 53.3%). The number of communicating branches was significantly higher in the curved type. The curved type also had a communicating vein penetrating the median septum, with the central branch passing deeper than in the straight type. The median septum could restrict the enlargement of communicating branches, causing thrombosis through disturbance of venous blood flow. Future research will clarify the median septum's influence on the soleal vein, potentially identifying soleus muscles at high risk of developing DVT. [ABSTRACT FROM AUTHOR]

Heterotopic ossification (HO) is a pathological condition characterized by ectopic bone formation in soft tissues. This study presents a rare case of anterior intercostal HO discovered in a 62-year-old Korean male cadaver during an educational dissection. The HO structure, which connected multiple ribs, underwent radiological examination (X-ray and CT scans) and histological analysis. Radiographic findings revealed that mature bone had formed adjacent to the ribs, surrounded by fibrous tissue. Histological analysis demonstrated a progression from fibrous tissue to mature bone, indicative of endochondral ossification, with no proliferative activity detected in the Ki-67 immunostaining. This case provides valuable insights into intercostal HO's morphological, radiological, and histological characteristics, providing significant information in anatomy and pathology for educational purposes. [ABSTRACT FROM AUTHOR]

Introduction Warfighters are issued hard body armor designed to defeat ballistic projectiles. The resulting backface deformation can injure different thoracoabdominal organs. Developed over decades ago, the behind armor blunt impact criterion of maximum 44 mm depth in clay continues to be used independent of armor type or impact location on the thoracoabdominal region covered by the armor. Because thoracoabdominal components have different energy absorption capabilities, their mode of failures and mechanical properties are different. These considerations underscore the lack of effectiveness of using the single standard to cover all thoracoabdominal components to represent the same level of injury risk. The objective of this pilot study is to conduct cardiac impact tests with a live animal model and analyze biomechanical injury candidate metrics for behind armor blunt trauma applications. Materials and Methods Live swine tests were conducted after obtaining approvals from the U.S. DoD. Trachea tubes. An intravenous line were introduced into the swine before administering anesthesia. Pressure transducers were inserted into lungs and aorta. An indenter simulating backface deformation profiles produced by body armor from military-relevant ballistics to human cadavers delivered impact to the heart region. The approved test protocol included 6-hour monitoring and necropsies. Indenter accelerometer signals were processed to compute the velocity and deflection, and their peak magnitudes were obtained. The deflection-time signal was normalized with respect to chest depth along the impact axis. The peak magnitude of the viscous criterion, kinetic energy, force, momentum and stiffness were obtained. Results Out of the 8 specimens, 2 were sham controls. The mean total body mass and soft tissue thickness at the impact site were 81.1 ± 4.1 kg and 3.8 ± 1.1 cm. The peak velocities ranged from 30 to 59 m/s, normalized deflections ranged from 15 to 21%, and energies ranged from 105 to 407 J. The range in momentum and stiffness were 7.0 to 13.9 kg-m/s and 22.3 to 79.9 N/m. The maximum forces and impulse data ranged from 2.9 to 11.7 kN and 1.9 to 5.8 N-s. The peak viscous criterion ranged from 2.0 to 5.3 m/s. One animal did not sustain any injuries, 2 had cardiac injuries, and others had lung and skeletal injuries. Conclusions The present study applied blunt impact loads to the live swine cardiac region and determined potential candidate injury metrics for characterization. The sample size of 6 swine produced injuries ranging from none to pure skeletal to pure organ trauma. The viscous criterion metric associated with the response of the animal demonstrated a differing pattern than other variables with increasing velocity. These findings demonstrate that our live animal experimental design can be effectively used with testing additional samples to develop behind armor blunt injury criteria for cardiac trauma in the form of risk curves. Injury criteria obtained for cardiac trauma can be used to enhance the effectiveness of the body armor, reduce morbidity and mortality, and improve warfighter readiness in combat operations. [ABSTRACT FROM AUTHOR]

Introduction Ventral hernia repair cost the U.S. healthcare system nearly 3 billion dollars annually. Surgical repair is a critical competency for residents yet hernia recurrence rates following mesh-based repair range from 0.8% to 24%. Improving surgical techniques using cadavers is often cost-prohibited for many education programs and limited research exists using simulation models with a corresponding hernia repair curriculum in the graduate medical education setting. This pilot project aimed to develop a low cost, easily reproducible novel abdominal wall reconstruction model and pilot-test the ventral hernia repair curriculum to inform further refinement prior to formal evaluation. Material and Methods This descriptive study pilot-tested the newly refined Abdominal Wall Surgical Skills Operative Model (AWSSOM) simulator for ventral hernia repair with mesh and its corresponding 2-h training curriculum for use at all levels of general surgery graduate medical education. The AWSSOM is a 3D printed synthetic anatomically realistic abdominal wall model consisting of silicone cured layers of skin, fat, rectus abdominis and a posterior rectus sheath fascia, and silicone tubules to simulate lateral neurovascular bundles. The curriculum incorporated didactic content reflecting surgical practice guidelines, hands-on practice, and faculty guidance promoting interactive critical thinking development during task performance. A pre-/post-assessment included a 10-item knowledge test, a 19-item psychomotor assessment, and 4-items confidence survey to examine changes in performance, knowledge, and confidence in competently completing the ventral hernia repair technique. Descriptive statistics were used to report the limited results of six military surgical resident participants and inform further model and curriculum refinement prior to formal evaluation. Results The five-layer AWSSOM model was manufactured in 65 h at a material cost of $87 per model frame, is reusable model, and secure base. Six surgical residents were recruited; only four completed both pre- and post-tests due to resident schedule conflicts. The average increase in knowledge was 25%, although variable changes in confidence were observed over the four program year participants. A larger sample size and a control group are needed to demonstrate curriculum effectiveness at improving knowledge, performance, and confidence in ventral hernia repair with mesh and better delineate if high scores translate to better operative skills. A key improvement requested by residents was a more secure model base for dissection and performance of the hernia repair. Conclusions The novel abdominal wall surgical skills operative model fills an important proof of concept gap in simulation training. It is low cost with the potential to improve cognitive and psychomotor skills, as well as confidence to competently complete ventral hernia repair with mesh in the graduate medical education setting. Prior to formal effectiveness testing, our lessons learned should be addressed in both the model and curriculum. Future studies must include an adequately powered statistical evaluation with a larger sample across all levels of training. [ABSTRACT FROM AUTHOR]