Translational Research in Anatomy最新文献

Research purpose

The sinoatrial node (SN) is the main pacemaker site, and it is located in the junctional area of the superior vena cava within the right atrium (RA). The precise micro-anatomy of the SN in males and females in ageing and obesity remains unclear.

Basic procedures

Human SN/RA specimens were dissected from 25 post-mortem hearts (preserved in 4 % formaldehyde solution), under Polish local ethical rules. The SN/RA tissue blocks were embedded in paraffin. Masson's Trichrome staining and immunohistochemistry for CD31 (a marker of endothelial cells) and CD68 (a marker of macrophages) were performed. Images at different magnifications were taken and analysed. 12-lead ECGs from 24 patients under Polish local ethical rules were obtained. Heart rate and P wave morphologies from lead II, lead III and lead aVF were analysed. Statistical analysis was performed with the unpaired t-test.

Principal results

Heart weight to body weight ratio was significantly higher in aged obese males vs. their female counterparts. In the RA samples, there was an increase in connective tissue and decreased myocyte content from aged obese females compared to aged obese males. Aged non-obese males had significantly increased cellular hypertrophy than the aged non-obese females. Both the aged obese and aged non-obese females showed more CD3 but less CD68 expressing cells than males. In the SN samples, CD31 and CD68 expressing cells were higher in both aged non-obese and aged obese males than their female counterparts.

Major conclusions

Ageing and/or obesity are more likely to impact these cardiac tissues through increased inflammation, increased immune response and hypertrophy.

Background

Arbor vitae cerebelli (tree-like branching white matter of the cerebellum) has a complex spatial configuration that is challenging to assess using conventional morphometric methods. This study proposes a fractal approach to describe and quantify the anatomy of Arbor vitae cerebelli. For this purpose, a new “contour scaling” method for fractal analysis of cerebellar white matter was developed.

Material and methods

The cerebella of 100 cadavers (50 male and 50 female) who died from causes unrelated to brain pathology, aged 20–95 years, were examined. Mid-sagittal sections of the cerebellar vermis were studied. The fractal dimension values of the cerebellar white matter were determined using both the developed fractal analysis method and the conventional “box counting” method, along with measurements of non-fractal parameters including cerebellar weight, area and perimeter of the vermis cross-section, perimeter-to-area ratio, and circularity.

Results

Considering the cerebellar white matter as a tree-like fractal, it was found to have 7 or 8 primary branches, which subdivide into 10-18 second-iteration branches, 19–38 third-iteration branches, and 34–53 fourth-iteration branches. Females more often had 8 primary branches compared to males, while males had a greater number of branches in the second to fourth iterations. The mean fractal (Hausdorff) dimension was 1.697 (1.721 in males, 1.674 in females, P = 0.01). The fractal dimension correlated most strongly with the perimeter and area of the vermis cross-section and had no significant relationship with age.

Conclusion

The fractal (Hausdorff) dimension, determined using the novel “contour scaling” method, quantitatively assesses the degree of branching of the cerebellar white matter. An increase in the absolute size of the cerebellum leads to a higher degree of branching of its white matter and an increase in the number of its constitutive components – white matter branches and folia.

Background

The value of formalin-fixed postmortem computed tomography (PMCT) has significantly increased in human anatomy education and research. However, improving embalmed PMCT images with high noise, low contrast, and multiple artifacts is an important challenge in enhancing the quality of clinical images. Retrospective denoising methods for embalmed PMCT data are essential for anatomical education and research when new-generation CT scanners with denoising functions are unavailable.

Methods

The three currently available standalone software denoising methods, including image summation methods (Fused CT), noise-reduction system methods (iNoir), and iterative reconstruction (IR, SafeCT), were used to analyze the retrospective noise-reduction effect on 13 human formalin-fixed PMCT datasets.

Results

Fused CT had some advantages; however, it was not useful for embalmed cadavers because of high noise, which doubled with the addition. iNoir and SafeCT improved the visual image quality of the noisy cadaver images. Statistical examination showed a 22–67 % and 18–56 % improvement in noise reduction in the non-artifact and metal artifact parts, respectively, depending on the methods and denoising intensities. However, this improvement was not statistically or morphologically significant in the presence of strong metal artifacts. In contrast, the scattered metal and streak artifacts peculiar to cadaveric images showed effective morphological and statistical improvement.

Conclusions

Retrospective denoising of embalmed PMCT images showed significant morphological and statistical improvements in noise reduction and is feasible for current anatomy education and research.

Background

Occipitalisation is the most prevalent congenital abnormality at the craniovertebral junction; however, it is rare in the general population. There is a paucity of literature on osteological prevalence studies within the South African Black and broader African populations. This study aimed to establish baseline data for the prevalence of occipitalisation in the South African Black population group.

Methods

One thousand two hundred thirteen skulls from a South African Black population were initially sampled, and after exclusion criteria were applied, the sample was reduced to 1119 skulls (male 766; female 353). A morphological description of the skulls that exhibited occipitalisation was included in this study.

Results

Occipitalisation was observed in three skulls (3/1119; 0.27 %); two of the skulls were female (2/353; 0.57 %), and one was male (1/766; 0.13 %). The three occipitalised skulls exhibited fusion in three areas of the atlas: the anterior arch, lateral masses, and transverse processes. No skulls exhibited posterior arch fusion of the atlas.

Conclusion

This study established a baseline prevalence of occipitalisation in the South African Black population at 0.27 % and found no significant association between sex and occipitalisation (p = 0.236). This study highlights the need for further studies in the other African population affinity groups.

Background

Recurrent laryngeal nerve (RLN) injuries account for most successful litigations against surgeons following head and neck surgery. Most injuries to the RLN occur during thyroidectomy with the best strategy to reduce injury to the RLN being through intraoperative monitoring of its normal anatomy, extra-laryngeal trajectory and topography. Identification of the RLN during thyroidectomy is possible at the tracheoesophageal groove (TEG), where it crosses the inferior thyroid artery (ITA) and or pierces the suspensory ligament of the thyroid gland (ligament of Berry). The extra-laryngeal course and branching patterns of the RLN are highly variable, increasing the likelihood of iatrogenic injury.

Materials and methods

The current study investigated the extra-laryngeal course, branching patterns and topographical relationships of the RLN in the TEG in adult cadavers and patients who underwent thyroidectomy. The study examined 30 thyroidectomy patients and 50 adult cadavers.

Results

The mean diameters of the RLN were 1.74 ± 0.59 mm and 1.63 ± 0.47 mm on the left and right sides, respectively, with no statistically significant difference between the genders and sides (P ≥ 0.05). The majority of the RLNs on the left side coursed in the first 0–15⁰ relative to the TEG while on the right side the majority deviated from the TEG at an angle ranging between 0 and 30⁰. The distribution of the RLN in relation to the inferior thyroid artery in the cadaveric sample was as follows: 29.6 % posterior to the artery, 33.7 % anterior to the artery and 36.7 % in-between its branches with statistically significant differences between genders (P ≤ 0.05). The majority of the RLN exhibited two or more branches on both sides, with a maximum of four branches being observed. In the surgical cohort, majority of the RLN ran posterior to the ITA followed by the anterior course and least in-between the branches of the ITA.

Conclusions

The present findings augment the vital information about the course, topography and branching patterns of the RLN along the TEG by outlining differences between the a cadaveric and a surgical sample as well as between two major South African population groups in order to minimise the iatrogenic injuries to the RLN and also to improve the diagnoses and management of the disorders of the neck, larynx and voice production.

Sacroiliac (SI) joint fixation is a technique used for SI joint fractures, SI joint dislocations and sacral fractures. Sacral screws can be placed either into the S1 or the S2 vertebrae if S1 is insufficient. Malpositioning of the screws is a common surgical complication as sacral variations exists amongst populations. Complications associated with the misposition of screws can lead to injury of the sacral venous plexus, iliac vessels, or sacral nerve roots. Therefore, this study aimed to evaluate sacral variations in a South African sample by determining distances between the first and second sacral foramina and classifying the common types of sacra found.

A quantitative cross-sectional comparative study was conducted. One hundred and twenty (n = 120) dry human sacra and 11 formalin-fixed cadavers were measured to determine the linear distances between the first two anterior and posterior sacral foramina. Additionally, the dry human sacra were classified according to Mahato's classification system. A cadaver SI joint fixation simulation was performed by an orthopaedic surgeon.

The mean sacral promontory height was found to be 31.81 mm and 37.52 mm in osteological and cadaver specimens, respectively. The mean anterior pedicle height was significantly different for the left (18.81 mm) and right (21.67 mm) side measurements. A statistically significant difference was found between cadavers and osteological samples for all measurements taken. In the osteological sample, ancestry and age mostly influenced the variations noted.

Using Mahato's classification system, sacra with five sacral segments, auricular surfaces extending from the superior part of S1 to the middle of S3 and no accessory L5/S1 articulations had the highest prevalence of 59.17 %.

The South African sample exhibited similarities but did not fully compare to other populations. The results in this study should be considered as a reference for surgeries involving the SI joint and sacral foramina. However, where possible, the exact anatomy with possible variations of the patient should be evaluated preoperatively using X-rays and angiograms.

Introduction

The present study evaluated the consistency and reliability of five anatomical landmarks in the external auditory meatus using CBCT (cone beam computed tomography) scans. The goal was to determine if these landmarks could reliably replace the commonly used point Porion for superimposing CBCT scans in clinical practice. Consistent anatomical features in the external auditory meatus are essential for accurate cranial assessments in dentistry and medicine. Despite their importance, these features have been underexplored, making this study a valuable contribution to improving clinical evaluation accuracy.

Materials and methods

22 CBCT scans were analyzed using ITK-Snap software. The shape of the External Auditory Meatus had been rendered by segmentation. These segmentations were used as a basis to locate the landmarks. The spread in location of the suggested landmarks concerning a reference coordinate system was treated as a measure for consistency. For that purpose, the absolute mean distance from all registered landmarks to the center of the location cloud was calculated for each dataset.

Results

The smallest spread in locations was measured for the so-called Epitympanic Notch, with 4.3 mm on average (SD 1.7). However, recognizing this landmark in the segmented images appeared to be relatively difficult. The landmark with the second smallest spread in locations (4.4 mm (SD 2.2)) and an easier recognition in the segmented image was the most superior point of the external auditory meatus. The most inferior point appeared to be the least reliable of all five landmarks.

Conclusion

Based on the present study, a consistently reliable landmark in the External Auditory Meatus to replace point Porion could not be identified. The hypothesis that any landmark could suffice for superimposing CBCT scans was not confirmed.