Theses and Dissertations (Anatomy)

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Investigating the effects of the heavy metals mercury, nickel and manganese, alone and in combination, on human erythrocytes and components of the coagulation system
(University of Pretoria, 2019) Oberholzer, Hester Magdalena; Taute, Helena; Van Rooy, Mia-Jeanne; masekobusisiwe@yahoo.com; Maseko, Precious Busisiwe
Heavy metals are major pollutants across the globe. Heavy metals are used in various industries and the waste matter is discarded in a manner that allows them to enter the soil, rivers and other parts of the environment. The widespread usage of heavy metals within different sectors such as agricultural, domestic and industrial areas raises an alarming concern over their impact on the environment and human health because of the wide spread contamination. Some metals are known to pose a danger to human health, while others such as copper and chromium are considered essential metals to humans and animals. However, chronic exposure to heavy metals may result in various ailments such as cardiovascular diseases, neurological- and behavioural disorders, and those affecting the immune system and kidneys. Blood cells play a crucial role in cardiovascular health where erythrocytes are responsible for the transportation of oxygen in the body and platelets and fibrin networks play a crucial role in the coagulation system also known as haemostasis. Abnormalities in haemostasis can result in haemorrhage or thrombosis. Heavy metals have been reported to cause alterations in erythrocytes influencing their function, morphology and distribution across the body, thus contributing to the pathophysiology of cardiovascular diseases. The aim of this study was to investigate the effects that the metals mercury, nickel and manganese alone and in combination, have on erythrocyte morphology and other components of the coagulation system by using the haemolysis assay, scanning electron microscopy and confocal microscopy. The metals in the study where chosen based on the likelihood of being exposed to them in South Africa. In this study, human blood was exposed to the heavy metals mercury, nickel and manganese ex vivo at concentration ranges of 1x, 10x, 100x, 1000x and 10000x the World Health Organization safety level standards for each respective metal. The World Health Organization safety level standards for these metals are: mercury = 6µg/L; nickel = 20µg/L; manganese = 400 µg/L. Blood samples were obtained from healthy male donors after written informed consent was obtained. Exposure of mercury caused increased haemolysis compared to nickel and manganese alone and in combination. At the highest concentration of 10000x all metals including the double and triple combination caused increased haemolysis. Results indicate that the erythrocytes membrane integrity was compromised resulting in haemoglobin leaking. Results provided by ultrastructural analysis indicated that the heavy metals (mercury, nickel and manganese) significantly impact on the shape of erythrocytes and structure of platelets and fibrin networks altering the coagulation system. Scanning electron microscopy results showed that with an increase in heavy metal exposure the erythrocytes lose their typical biconcave morphology and become echinocytic with a bulging appearance visible with increased membrane roughness. Platelet membrane spreading and presence of pseudopodia increases, and fibrin networks appeared unorganized with increased membrane roughness observed in all the single metal groups (Hg, Ni and Mn) and combinations (Hg+Ni, Hg+Mn, Mn+Ni and Hg+Ni+Mn). Confocal microscopy results showed that the membrane phospholipid, phosphatidylserine, was translocated from the internal membrane leaflet to the outer surface of the membranes of erythrocytes exposed to all three metals alone (Hg, Ni and Mn) and in combination (Hg+Ni, Hg+Mn, Mn+Ni and Hg+Ni+Mn), this could indicate eryptosis of erythrocytes. The morphological changes of erythrocytes, platelets and fibrin networks may cause weakened capacity for erythrocytes to carry oxygen effectively, impair the coagulation system resulting in thrombosis and additionally prevent the restoration of homeostasis of the body. The outcome of this study provides a better understanding of the effect of these metals on the coagulation system and the negative impact on human health.
Creating guidelines for the approximation of the eye and periorbital regions of South Africans using cone beam computed tomography scans
(University of Pretoria, 2024-05-31) Oettlé, Anna Catherina; L'Abbé, Ericka Noelle; Ridel, Alison Fanny; duplessis.son@gmail.com; van der Walt, Soné
Introduction: South Africa is experiencing a rise in unidentified remains yearly, and due to poor access to healthcare and illegal immigration, standard identification methods often fail. The foundational data used to reconstruct South African faces are based on North American cadavers which result in inaccurate reconstructions. This study aimed to create guidelines for approximating the eyeball and periorbital structures for South African groups using cone-beam computed tomography (CBCT) scans. Methods: Retrospective CBCT scans of 206 South African adults (45 black females, 52 black males, 57 white females, and 52 white males) were included in the study, of which 187 had open eyes (32 black females, 51 black males, 52 white females, and 52 white males). Three-dimensional landmarks were placed manually on the hard- and soft-tissue renderings of the face and skull as well as the outline of the eyeball in 2D using the MeVisLab © v.3.0.2 software. The 3D coordinates of these landmarks were used to calculate the linear dimensions of the orbit, eyeball, palpebral fissure, and the position of the eyeball in relation to the orbital rim. Predictive equations and predictions based on proportionality for the position of the eyeball in relation to the orbital rim, eyeball and palpebral fissure dimensions were derived from these linear dimensions. The effect of sex and population affinity on the shape of the orbit and palpebral fissure was investigated using geometric morphometric methods (GMM). The second part of the study entailed the creation and validation of prediction models based on the relationship between shape of the bony orbit and palpebral fissures using an automatic landmarking method. Results: Sex and population affinity significantly affected the dimensions and shape of the orbit, eyeball and palpebral fissures. Black females had significantly smaller eyeballs which protruded more from the superior orbital margin than the other sex-population groups. Eyeball position, eyeball dimensions and palpebral fissure dimensions could be predicted with greater accuracy based on proportionality compared to linear regression formulae. Variations in the palpebral fissure dimensions in black South Africans were driven by shape, while it was driven by size in white South Africans. Population affinity had a greater effect on the shape of the orbital region and palpebral fissures than on the linear dimensions. The shape analysis based on the automatically placed landmarks concurred with this finding which resulted in the accurate prediction of the open eye from the underlying bony tissue with a small measurement error, especially when population affinity was added as a factor. Conclusion: When reconstructing South African faces, it should be noted that black South African females had significantly smaller eyeballs compared to all other groups, while the eyeball protruded more in the vertical plane in black South Africans than white South Africans. Black compared to white South Africans had a greater inner canthal distance and less upward slanting palpebral fissures. Instead of depending on normative dimensions, the palpebral fissure and eyeball position can be predicted based on the morphology of each individual without considering sex or population affinity. The open eyelids could be accurately predicted from the underlying bony tissue for the use in automatic facial approximations. These prediction results should be combined with prediction models of other facial features to create accurate, objective and less time-consuming automated facial approximations of South Africans.
Prediction of the soft-tissue facial morphology matrices in a European population, a Geometric Morphometric study using Cone- Beam Computed Tomography.
(University of Pretoria, 2023) Ridel, A.F. (Alison); L'Abbe, Ericka Noelle; thandombonani83@gmail.com; Mbonani, Thandolwethu Mbali
The increasing number of unidentified and unclaimed bodies at state mortuaries in Gauteng, the smallest yet most densely populated province in South Africa, has become a cause for concern for the Health Department (Sobuwa, 2023). The socioeconomic backgrounds of these victims pose challenges in the identification process, as the usual methods like dental records or DNA/fingerprint comparisons are often unavailable. This is primarily due to the high cost of DNA testing and the lack of regular dental care among most South Africans, resulting in a lack of comparative records. Consequently, alternative approaches such as craniofacial reconstruction need to be explored to facilitate the identification process. The purpose of this research was to examine the impact of various factors, such as population affinity, sex, age, and allometry, on the variation in craniofacial shape. Additionally, the study aimed to investigate the correlation between the morphology of hard and soft tissues in the face using cone-beam computed tomography (CBCT) scans, and to develop prediction models based on these findings. For this study, a total of 76 white South Africans and 108 French nationals, with ages ranging from 18 to 80 years, were included. The CBCT scans utilized in this research were obtained retrospectively from two different sources. Specifically, the CBCT scans of the South Africans were collected from the University of Pretoria's Oral and Dental Hospital as well as the Groenkloof Life Hospital in South Africa. On the other hand, the CBCT scans of the French nationals were obtained from the University of Bordeaux in France. Landmarks were selected on both the facial skeleton (including orbits, nasal bones, anterior nasal aperture, zygoma, and maxilla) and the soft features of the face (ears, eyes, nose, and mouth) to create regions of interest. A total of 43 craniometric landmarks, including 559 sliding landmarks, were registered on the hard-tissue surfaces, while 50 capulometric landmarks were registered on the soft-tissue surfaces using the MeVisLab© v. 2.7.1 software. Geometric morphometric techniques were employed to analyze the craniofacial shape differences associated with population affinity, sex, age, and allometry. Furthermore, two- blocks partial least squares (PLS) analyses were used to assess the covariation between the matrices of hard and soft tissues in each sample. Finally, the Projection onto Latent Structures Regression (PLSR) algorithm was utilized to develop predictive statistical models based on the obtained data. The analysis of the physical structure of both hard and soft tissues in the facial region can aid in identifying the degree of connection between the underlying skull and the soft facial features. This can lead to a more comprehensive understanding of the factors that contribute to the variations in craniofacial morphology among diverse populations. The interrelation between the bony structures of the face and the soft facial features is crucial for the development of craniofacial reconstruction techniques, and comprehending this association can facilitate the creation of precise predictive models. The shape variation of the facial skeleton and soft facial features were influenced by population affinity, sexual dimorphism, ageing, and allometry, according to the findings. The impact of population affinity was the most significant (p-value < 0.05), with population- specific differences observed between white South Africans and the French. The effects of sexual dimorphism and ageing differed between the two populations, with specific hard and soft tissue elements affected by these variables. Additionally, the correlations between hard and soft tissue matrices were notably different between the two populations. Overall, the study highlights the importance of considering population affinity, sex, and age when reconstructing the face and emphasizes the need for accurate prediction models specific to different populations. The PLSR method was utilized in this study to create reliable predictive models, which were further improved by incorporating additional parameters such as population affinity, sex, and age. The study found that age and sex were crucial factors to include as supplementary information in order to enhance prediction performance. The analysis was conducted on 184 specimens, and the precision of the estimated soft-tissue shape of the ears, eyes, nose, and mouth was evaluated using metric deviations on both trained and untrained datasets. The trained data showed that the prediction errors for the ears, eyes, nose, and mouth for white South Africans were 2.299 mm (SD 0.132), 2.069 mm (SD 0.154), 2.523 mm (SD 0.145), and 3.573 mm (SD 0.003), respectively, while prediction errors for the French group were 2.693 mm (SD 0.064), 2.248 mm (SD 0.040), 2.643 mm (SD 0.165), and 3.585 mm (SD 0.003). On the other hand, prediction errors on non-trained data were slightly greater, with errors of 3.038 mm (SD 0.132), 1.976 mm (SD 0.154), 3.266 mm (SD 0.317), and 3.774 mm (SD 0.301) reported for white South Africans' ears, eyes, nose, and mouth, respectively, whereas prediction errors of 3.432 mm (SD 0.064), 2.155 mm (SD 0.040), 3.386 mm (SD 0.317), and 3.572 mm (SD 0.294) were recorded for the French group. The present study aimed to assess the effects of population affinity, sex, age, and allometry on the shape components of facial matrices composed of hard and soft tissues. The findings of this investigation demonstrated notable variations in craniofacial morphology between white South Africans and French individuals. These results underscore the importance of comprehending and quantifying the impact of these factors, as it can significantly improve the accuracy of prediction models when applied to specific populations. Ultimately, this research contributes to a better understanding of the intricate relationship between population characteristics and facial shape.
Evaluating external and internal root and canal morphology of first molars in Black South Africans
(University of Pretoria, 2023-12-12) Oettle, Anna Catherina; Foschi, Federico; L’Abbé, Ericka Noelle; casper.jonker@plymouth.ac.uk; Jonker, Casper Hendrik
Introduction The aims and objectives of this project were to: 1) to standardise the determination of the orifice location of root canals using micro-CT and the pulp floor, 2) describe main root canal configurations using the Ahmed et al. classification system criteria, 3) describe a novel classification system for complex root canal configurations and 4) describe the root and canal morphology of mandibular and maxillary first molars in Black South Africans. Methods This is a descriptive, retrospective, observational and cross-sectional study evaluating root and canal morphology of 187 first molars. Firstly, orifice location was determined using Avizo software and stable landmarks. Root canal configurations were determined by using the Ahmed et al. classification system criteria (main canals) and the newly developed method (complex configurations). The new classification system consists of four groups (A to D) and three subtypes (1 to 3). Root and canal morphology were evaluated which included a calculation of the number of roots and canals. The relationships between sex and arch sides on root and canal morphology were recorded. Results The newly developed methodology to determine orifice location could accommodate all molars using minor modifications. According to the Ahmed et al. classification, the most common maxillary configuration was 3MXFM MB1DB1P1 (n=33/93, 35.5%) (three separate roots). Configurations in mandibular molars were more diverse and the most common configuration was 2MDFM M1-2 D1 (n=8/84, 9.5%). According to the new classification system, the most common type of configuration in all teeth was Type 3 (A3, B3, C3, and D3). Maxillary molars more often classified as A3 (n=47/101, 46.53%) and D3 more often in the mandible (n=26/86, 30.23%). In maxillary molars, a relationship was found between configuration type and age groups but not between sides or sex. No relationship was noted between sides, sex and age and configuration types in mandibular teeth. Statistical significance level was set at a 5%. All maxillary molars had three roots (separate or fused). Root fusion was found in 7.9% of maxillary molars (n=8/101). Most mandibular molars had two roots and no fusion was noted. A Radix Entomolaris (RE) was found in 2.3% of teeth (n=2/86). Three and four canals were common in maxillary and mandibular molars: 39.6% (n=40/101), 50.49% (n=51/101) and 55.81% (n=48/86), 24.42% (n=21/86), respectively. In maxillary molars, the second mesiobuccal canal was identified in 60.39% (n=61/101), the third mesiobuccal canal in 5.94% (n=6/101) and fourth mesiobuccal in 0.99% (n=1/101) of teeth. In mandibular molars, the middle-mesial and middle distal canals were found in 18.60% (n=16/86) and 3.49% (n=3/86) of molars, respectively. Conclusions The proposed classification system was repeatable and could 1) accommodate all complex configurations, 2) compare root canal configurations between jaws, 3) determine the degree of complexity of the root canal complex with possible clinical implications, 4) indicate which teeth should be considered for referral for specialist care and 5) be useful in future studies. Root canal anatomy of mandibular molars is more complex than previously thought. Treating clinicians should take note for diagnostic and treatment planning purposes for Black South Africans.
Assessment of the associations of age with the classic skeletal sex indicators
(University of Pretoria, 2024) Liebenberg, Leandi; Brits, Desiré; Myburgh, Jolandie; sarahkellyhouston@gmail.com; Houston, Sarah-Kelly
Forensic anthropologists are often required to establish a biological profile from skeletal remains, which includes the estimation of biological sex. The Walker and Phenice traits are morphoscopic methods frequently utilised to estimate sex from unknown skeletal remains. The methods employ five traits located on the skull and three on the os coxae and are considered the classic morphological skeletal sex indicators. Previous literature has stated that the growth and deterioration related to aging that occurs throughout an individual’s life may affect the classic morphological skeletal sex indicators and therefore the estimation of sex. More specifically, females are reported to become more robust with older age, while younger males appear more gracile. This overlap in sexual dimorphism leads to greater misclassification and decreased accuracy in medicolegal casework. The aim of this study was to assess if age needs to be considered when attempting to classify sex using the classic morphological sex indicators. The sex indicators were scored on a sample of 453 skulls and 429 os coxae of modern South Africans. The scores were then compared among ten different age cohorts. Separate age-specific classification models were created to assess if age affects the positive predictive performance of the sample. Significant differences were identified for the nuchal crest between age cohorts younger and older than forty years of age with the sample pooled. None of the other cranial traits demonstrated any significant differences. Regarding the classification models, accuracies increased for the younger group when separated from the older group, but the opposite was shown to be true for the older group. The os coxae did not show significant differences between the ten age cohorts. However, when separated into three large cohorts (younger, middle-aged, older) differences in accuracy was apparent between the cohorts. The results indicate that preselection of age prior to sex estimation is not necessary in a South African population. Further research is required to identify additional explanations for misclassification with sex estimation, as age does not appear to be a major influential factor for the classic morphoscopic sex indicators.
Creating a statistical shape model to aid in the estimation of incomplete soft tissue segments of the surface of South African faces
(University of Pretoria, 2024-02-14) Oettlé, Anna Catharina; L'Abbe, Ericka Noelle; Matthews, Harold; franci.dorfling@gmail.com; Swanepoel, Heléne Francia
Introduction: A critical gap exists in population-specific data for facial morphology of black South Africans which are essential for the accurate reconstruction of facial features in fields such as aesthetic and reconstructive surgery, prosthodontics and extra-oral facial prosthetics, as well as forensic facial approximations. The objectives of this research were to generate normative reference values of black South African faces for various inter-landmark distances, and to derive a statistical shape model (SSM) of 3D facial shape variation which can be applied to estimate missing soft tissue segments on simulated defective faces. Methods: The study included of 235 computed tomography (CT) and cone-beam computed tomography (CBCT) scans from black South African individuals between the ages of 18 and 87 years. The scans were collected from retrospective records of three medical institutions and excluded individuals that showed conditions potentially affecting facial morphology, including orthodontic treatments, pathological conditions, facial asymmetry, or any history of facial reconstructive surgery. The scans were processed to obtain 3D facial meshes and landmarks were placed at anatomically important loci. For the first objective, inter-landmark distances were calculated, statistically analysed, and compared to published literature on other populations. For the second objective, correspondence of the 3D meshes utilising the landmarks were achieved, and generalised Procrustes analysis and principal component analysis conducted. These steps are crucial in obtaining an SSM comprising the modes of variation and the normal range variance along each mode, which together defines multinormal parameterisation of shape variation. Defect estimations were done by using the SSM to estimate the linear combination of the modes of variation that most closely approximates the intact regions of each face, and estimate the missing regions using a weighted projection onto the modes of variation. Results: Chapter 3 reports on normative facial capulometric measurements specific to the black South African population. It highlights significant differences in facial parameters between sexes and between different populations. The data reveal notable similarities with other African populations, especially in oral features, but significant disparities with non-African groups. Chapter 4 introduces the innovative SSM for extra-oral prosthetic design. This model accurately estimates missing soft tissues, demonstrating a high degree of precision with root mean square errors consistently below 2.58 mm for various facial defects. Conclusion: The normative measurements highlight the unique facial characteristics of the black South African population, demonstrating the necessity of population-specific data in clinical and forensic applications. The development of the SSM represents a novel advancement in digital reconstruction methodologies. It offers a more objective and patient-specific approach in prosthetic design, especially in addressing complex facial defects such as bi-orbital defects or those crossing the facial midline in a demographic that has been largely overlooked in previous research. This model, by reducing the subjectivity and artistic skill previously required in prosthetic design, aligns with the evolving digital trends in medical technology and aims to address specific local needs and challenges in South Africa, and also have potential for global application.
An evaluation of the cranial variation of Indian South Africans in comparison to other modern South Africans
(University of Pretoria, 2024-02-13) L'Abbe, Ericka Noelle; Jantz, Richard L.; gabi.kruger@up.ac.za; Krüger, Gabriele Christa
Constant re-evaluation of standards used in forensic anthropological analyses are necessary, particularly as new methods are explored or populations change. Even though Indian South Africans are not a new addition to the South African population, the lack of skeletal material available for analysis has resulted in a lack of information on the variation present in the crania of this group. Furthermore, although black, white and coloured South African crania have been previously researched and standards created, by similarly making use of three-dimensional (3D) models created from computed tomography (CT) scans, the data are comparable to the Indian South African data collected and all four groups could be explored simultaneously. The aim of this project was to use 3D CT models to explore cranial variation in Indian South Africans when compared to current black, coloured and white South Africans to distinguish among the groups when estimating sex and population affinity from the cranium. 3D cranial models were created from 409 head CT scans of black, coloured, white and Indian South Africans (equal sex and population distribution). A total of 42 landmarks were recorded on each skull. The coordinates were used to assess shape differences using geometric morphometrics, generalized Procrustes analysis and principal component analysis. Standard and non-standard interlandmark distances (ILD) were also created from the landmark coordinate data and assessed using analysis of variance for significant sex and population differences, and symmetric percent differences for comparisons of the degree of sexual dimorphism among the different population groups. Furthermore, linear discriminant analysis (LDA) was used to assess the classification potential of the various ILDs to estimate sex and population affinity. Four morphoscopic traits were also scored on each cranium according to the methodology by Walker (2008). The scores were then assessed for their ability to separate between the sexes in each of the population groups using ordinal logistic regression and random forest modelling. Indian South Africans obtained the highest correct classification rates for sex using morphoscopic traits (95.7%) and demonstrated substantial differences between Indian South African males and females for the ILDs. Similarly, the remaining three population groups had excellent correct classification rates for the morphoscopic traits (88.0% - 91.5%) and sex could be estimated with high rates using ILDs (90.7%). Furthermore, acceptable classification rates were obtained when estimating population affinity for the four South African populations when the ILDs (up to 62.2%) and 3D coordinates (up to 63.8%) were assessed, indicating cranial differences among the four groups. Even though population affinity could be estimated, substantial overlap between coloured, Indian and white South Africans was noted, most likely due to the similarities in genetic influences that have contributed to the various populations. The assessment of current Indian South Africans as well as the exploration of the cranial variation present in the other three larger current South African populations, was only possible through the use of 3D cranial models created from head CT scans, and was able to provide novel information that can be applied in both biological and forensic anthropology. Keywords: computed tomography, sex estimation, population affinity, Indian South Africans, cranial variation, morphoscopic, random forest modelling, geometric morphometrics, linear discriminant analysis, interlandmark distances.
South African cranial variation : a combined metric-macromorphoscopic method for ancestry estimation
(University of Pretoria, 2023-11-20) L'Abbe, Ericka Noelle; Stull, Kyra Elizabeth; leandi.liebenberg@up.ac.za; Liebenberg, Leandi
Ancestry is a fundamental parameter of the biological profile. To date South African forensic anthropologists are only able to successfully apply a metric approach to estimate ancestry from skeletal remains. While a non-metric, or macromorphoscopic (MMS) approach exists, limited research has been conducted to explore its use in a South African population. The method has not been sufficiently tested and validated which is required for anthropological methodology to be compliant with standards of best practice. This study aimed to explore the MMS traits and its covariation with cranial measurements to develop improved methodology for the estimation of ancestry from skeletal remains in South Africa. A suite of 17 MMS traits and 25 standard linear measurements were collected from 660 crania of black, white and coloured South Africans. Inter- and intra-observer agreement was closely scrutinized as visual methods have been shown to be prone to error. The intra-observer agreement ranged from moderate to perfect, with three traits (inferior nasal margin, nasal bone shape, and nasal overgrowth) yielding slightly lower repeatability. Inter-observer agreement was assessed among five individuals with varying levels of general experience and familiarity with the traits. Overall, the observers demonstrated poor to substantial agreement. A group discussion on the scoring procedure, followed by subsequent rescoring of the crania showed a slight increase in overall agreement, with kappa values ranging between moderate and substantial. While general experience does not appear to translate to proficiency with the method, familiarity with the traits and scoring procedure contributes to consistent scores. Thus, method-specific training is essential prior to employing the MMS traits in practice. Technical error of measurement was used to assess the repeatability of the measurements, where the intra-observer error was noted to be lower than the inter-observer error. The greatest disparity was observed with the inter-orbital breadth and mastoid height for both the inter- and intra-observer assessments. The MMS trait frequency distributions revealed substantial group variation and overlap. Ultimately, not a single trait can be considered characteristic of any one population group. Kruskal-Wallis and Dunn’s tests demonstrated significant population differences for 13 of the 17 traits. Black and coloured South Africans, and coloured and white South Africans shared similarities for many of the traits, but black and white South Africans did not present with significant overlap for any trait. ANOVA and Tukey’s honestly significant difference (HSD) test revealed that all measurements were significantly different for ancestry, except the foramen magnum length. Substantial variation and overlap were observed for the measurements among all three groups. Random Forest Modelling (RFM) was used to develop classification models to assess the reliability and accuracy of the variables in identifying ancestry. Models were created for the traits and measurements separately to gauge the discriminatory power of each dataset. A combined model including all data was also created to test if mixed data can better capture cranial variation than individual methods. The MMS model outperformed the metric model, with classification accuracies of 79% and 72%, respectively. Ultimately, the best results were obtained with the mixed model, which yielded an accuracy of 81%. The results indicate that the combination of size and shape data (as quantified with the mixed model) can effectively distinguish between black, white and coloured South Africans despite significant group overlap. Thus, this study has shown the MMS traits to be a valid and tested method, and the population-specific data from this study can be used to add MMS analyses to forensic casework and skeletal analyses in South Africa.
Descriptive anatomical study of the dorsalis pedis artery for use in clinical and surgical procedures
(University of Pretoria, 2023) Mogale, Nkhensani; Tshabalala, Zithulele Nkosinathi; Myburgh, Jolandie; obakengc.modisane@gmail.com; Modisane, Obakeng
Variations of the dorsalis pedis artery (DPA) are quite common, and may result in complications and misdiagnosis. A variation that results in a deviated DPA from the anterior ankle or one with an abnormal origin may lead to misdiagnosis of peripheral arterial disease due to an undetected/absent pulse. Complications that may occur include haemorrhages caused by severed arteries as a result of variations that lead to changes in positions/locations on the foot from their known origins. Non-viable flaps and grafts may be selected due to variations that result in reduced arterial supply and changes in calibres of blood vessels. As a result of these complications suggestions of amputations may be considered due to misdiagnosis of an absent pulse and the presence of peripheral arterial disease. The DPA is the main blood supply of the dorsum of the foot and the continuation of the anterior tibial artery. The DPA branches into the medial and lateral tarsal arteries, the arcuate artery (which branches into the second to fourth dorsal metatarsal arteries), the first dorsal metatarsal artery and deep plantar artery. The DPA is clinically essential for the detection of pedal pulsation. DPA and its branches can be used as flaps/pedicles for bypass grafts during plastic and reconstructive repairs, in complications that involve amputations of ischaemic limbs in diabetic patients. The current study investigated the anatomy of DPA, its branching pattern and position on the anterior ankle joint in a cadaveric sample and by using angiograms. The proposed sample size for the cadaveric component of the study was 200 feet from 100 formalin-fixed adult cadavers, while only 18 cross-sectioned computed tomography (CT) scans were used from a total of 21 scans. The cadaveric study concluded that, a common branching pattern of the DPA was found in an incidence of 11.56% in 147 feet, while fourteen (14) branching patterns of the DPA (A to N) were recorded. The findings of the current study suggest that variations of the DPA are common. Results from the cadaveric study show the average distance of the intermalleolar line (LM-MM) was reported as 69.30 mm. The average distances from the lateral and medial malleoli to the origin of the DPA were 47.19 mm and 39.61 mm, respectively. The average diameter of the DPA was found as 2.37 mm. Comparisons were made between the cadaveric study and angiogram study, with both studies revealing that the position of the DPA on the ankle was slightly located on the medial side. Vascular mapping of the small and distal arteries of the foot remains a challenging task to perform. The DPA remains at risk of injury during surgical interventions such as reconstructive and plastic repairs, as well as ankle arthroscopy. Thorough knowledge of the anatomy of the DPA and its branches is essential in the correct and accurate vascular mapping of the distal arteries of the foot for teaching, as well as in clinical and surgical interventions. This knowledge will assist clinicians and surgeons in the correct detection of the pedal pulsation, thus reducing occurrence of misdiagnosis. This knowledge will also assist surgical planning prior to surgical interventions such as ankle arthroscopy, in preventing risk of injuries to the DPA, as well as finding viable bypass grafts in treating ischaemic limbs, thus reducing lower limb amputations.
Evaluation of the bioactivity and stability of gold nanoparticles conjugated with Os-C(W5) against Candida albicans biofilms
(University of Pretoria, 2023) Bester, Megan J.; Gaspar, A.R.M. (Anabella Regina Marques); Jeanmonepalm@gmail.com; Palm, Pierre Jean-Moné
The increased prevalence of antimicrobial resistance has led to the need for new antimicrobial drugs with novel modes of action. Antimicrobial peptides (AMPs) are cationic peptides that, in contrast to traditional antimicrobials targeting specific cellular components, exhibit varied mechanisms of action by engaging in a non-specific manner to disrupt the integrity of microbial membranes, thereby diminishing the probability of resistance development. Although promising antimicrobial agents, the main challenges are low activity in physiological environments and loss of activity in the presence of proteases. These limitations can be overcome with several different approaches including amidation, tryptophan (Trp) tagging, inclusion of unnatural amino acids, and various formulation strategies. Os-C is a cationic AMP, an analogue derived from a defensin identified in the midgut of the tick Ornithodoros savigny. Despite Os-C exhibiting noteworthy antibacterial and antifungal properties, Os-C exhibited reduced activity in physiological environments, impeding potential clinical application. The attachment of five Trp residues to the terminal ends of Os-C led to analogues (W5)Os-C and Os-C(W5), which exhibit antimicrobial activity in physiological environments. To further develop these analogues for antifungal treatment it was necessary to further reduce their susceptibility to proteases. Recent studies have shown that the presence of Trp residues on the N-terminal of a peptide reduces gold (III) chloride, resulting in the formation of gold nanoparticles (GNPs) coated with peptide. This method offers the advantage of easy synthesis without the use of toxic chemicals or the formation of toxic by-products. Therefore, it is ideal for physiological applications. The aim of this study was to synthesise and characterise (W5)Os-C and Os-C(W5) conjugated onto GNPs. For the more stable peptide-coated GNPs, then to determine the antifungal activity against C. albicans biofilms, cytotoxicity against human epidermal cells and nitic oxide (NO) anti-inflammatory properties. Both Os-C(W5)@GNPs and (W5)Os-C@GNPs were successfully synthesised. Os-C(W5)@GNP proved to be the most stable, and further studies were conducted with this analogue. Os-C(W5)@GNPs had a quasi-spherical structure with an average diameter of 14.62 ± 0.31 nm. High-magnification TEM imaging revealed a distinct corona, affirming the presence of peptides on the surface of the GNPs, quantified at 2.4 ± 0.15 nm. Approximately,174.96 of peptides were estimated to be bound per nm2. Subsequent circular dichroism studies revealed that Os-C(W5) retained a disordered secondary structure when bound to the GNP surface. As this was the first study in which AMPs were bound to GNPs using this method of non-covalent conjugation, it was necessary to determine if the antibiofilm activity of Os-C(W5) is v retained. The activity of Os-C(W5)@GNP against C. albicans was assessed using the biofilm inhibition (50% biofilm inhibitory activity (BIC50)), eradication (50% biofilm eradication activity (BEC50)), and degradation (50% biofilm degradation activity (BDC50)) assays, with miconazole as a drug control and Tyr@GNP as a GNP control. Compared to Os-C(W5), the BIC50 for cell viability and biomass of Os-C(W5)@GNP was similar. The BIC50 for cell viability was 7.40 ± 0.42 μM for Os-C(W5) and 8.93 ± 1.24 μM for Os-C(W5)@GNP. The respective BIC50 values for biomass were 7.07 ± 0.57 μM and 5.99 ± 2.28 μM. Light microscopy of stained biofilms revealed a less dense biofilm with some budding hyphae. The GNP control, Tyr@GNP, displayed no biofilm inhibitory activity, suggesting that released Os-C(W5) rather the GNPs inhibited the development of C. albicans biofilms. Determining the BEC50 for Os-C(W5)@GNP was not feasible since the GNPs reached their maximum concentration at 37.5 μM, which was still below the anticipated BEC50. Nevertheless, notable effects were observed at this highest concentration, including, 50% inhibition of cell viability and 15% inhibition of biomass. The BDC50 for Os-C(W5)@GNP was 45.7 ± 5.9 μM and >150 μM for cell viability and biomass respectively, indicating that Os-C(W5)@GNPs was cell targeting rather than targeting the biofilm synthesis pathway. Os-C(W5)@GNPs showed no cytotoxicity after evaluated in the HaCat cell line when compared with melittin, a cytolytic AMP. Os-C(W5)@GNPs maintained biofilm inhibitory activity in artificial saliva, a physiological salt solution lacking the biomolecules present in human saliva. A lack of activity was observed in human saliva, potentially due to the presence of salivary proteins, proteases, and mucin. Previous studies have shown that Os-C and related analogues, such as Os, are multifunctional and possess anti-inflammatory activity, which is related to the ability of these AMPs to scavenge NO. In contrast to glutathione and Os, Os-C had reduced activity. Trp tagging and subsequent binding to GNPs did not increase NO scavenging activity. To conclude, Os-C(W5)@GNP localises a high concentration of Os-C(W5) onto GNPs, via non-covalent bonding. Compared with Os-C(W5), biofilm inhibitory activity was retained while biofilm eradication and degradation activity were minimal. Os-C(W5)@GNP was not cytotoxic at the concentrations evaluated and lacked NO scavenging activity.
Neopterin and neurophysiological measurements as markers of anxiety and stress
(University of Pretoria, 2023) Bipath, Priyesh; Du Toit, Peet J.; rouxzanc@gmail.com; Cronje, Rouxzan
Background: Mental health is an increasing global crisis. It has large social, economic, and health costs, with stress and anxiety disorders accounting for a large portion of the impact. Biomarkers may help to improve the understanding and management of mental health conditions. Aim: The aim of this study was to investigate whether neopterin and certain neurophysiological measures could be used as complementary markers for stress and anxiety symptoms as determined by the Depression, Anxiety, and Stress Scale (DASS-21). Methods: A sample cohort of 158 respondents completed the DASS-21 and biographical questionnaire, which were used to stratify Health Science university students between Group A (n=20), who had high levels of symptoms, and Group B (n=20) who had normal levels of stress and anxiety. Neurophysiological measurements were taken from these participants, namely heart rate variability (HRV), blood pressure (BP), blood-volume pulse (BVP), electrodermal activity (EDA), and quantitative electroencephalography (qEEG). The participants also donated a urine sample which was tested for neopterin concentration (a non-specific biomarker of inflammation) using an enzyme-linked immunosorbent assay (ELISA). Results & Discussion: Neopterin positively correlated with the stress and anxiety scores, while HRV and BVP were negatively correlated with these scores. In terms of qEEG, delta and hibeta wave activity increased in the left and frontal brain regions in participants with high mental health scores, whereas alpha wave activity decreased in these regions. High DASS scores were associated with elevated neopterin concentration and neurophysiological changes (brain waves, HRV, and BVP). Conclusion: The associations between inflammation, neurophysiology, and mental health need to be addressed and further investigated to mitigate further health and economic burden.
Anatomical investigation of the interthalamic adhesion
(University of Pretoria, 2023) Venter, Gerda; Prigge, Lané; Taute, Helena; nicole.vanheerden@tuks.co.za; Van Heerden, Nicole
Due to the lack of literature investigating the function of the interthalamic adhesion (IA), uncertainty surrounds its significance and clinical importance within the brain. However, existing literature has been able to show a physical anatomical correlation with neurological disorders, such as schizophrenia. Only recently have studies provided limited insight into the role of the IA in the neural network of the brain, thus opening new avenues of investigation that will further our understanding of the neuroanatomy and the associated clinical implications. The aim of this study was to conduct a descriptive, observational cross-sectional investigation of the IA in a sample of the South African population. This anatomical investigation included reports on the prevalence, location, shape, size and area of the IA and further correlated these factors with age and sexual dimorphism. In addition, this study included a histological investigation of the neuron arrangement within the IA to observe a possible implication of cell architecture for IA function. This study used a sample of human brains dissected from bodies donated to the Faculty of Health Sciences at the University of Pretoria. Digital photography of midsagittal brain sections and scientific image-processing software (ImageJ) was used to generate the necessary measurements. The data collected in this study was compared to known literature on the IA, noting the differences and similarities. The significance of the results was reported on. This study provided an anatomical foundation on which to conduct further functional investigation in research of the IA within the human brain and provided a novel look into the histology of the IA and surrounding periventricular region (PVR).
A cadaveric study to test the viability of pre-determined safe zones for arthroscopic portal placement into the posterior knee
(University of Pretoria, 2022) Mogale, Nkhensani; van Zyl, Reinette; Keough, Natalie; Hohmann, Erik; greenwood.kelsi@gmail.com; Greenwood, Kelsi
The posterior compartments of the knee are currently accessed arthroscopically through anterior, posteromedial or posterolateral portals. A direct posterior portal to access the posterior compartments has been overlooked due to a perceived high-risk of injury to the popliteal neurovascular structures. Therefore, this study aimed to investigate the safety and accessibility of a direct posterior portal into the knee. Method: This cross-sectional study comprised a sample of 95 formalin-embalmed cadaveric knees and 9 fresh-frozen knees. Cannulas were inserted into the knees in pre-defined safe zones. Measurement of the distance between the cannula and popliteal neurovascular structures was performed and damage to neurovascular structures noted. Fresh-frozen knees underwent needle arthroscopy to assess the technique in clinical settings. Results: Incidence of neurovascular damage was 9.6% (n=10); 0.96% for the medial cannula and 8.7% for the lateral cannula. The medial cannula damaged one small saphenous vein (SSV). The lateral cannula damaged one SSV, seven common fibular nerves (CFN) and both the CFN and lateral cutaneous sural nerve in one specimen. All incidences of damage occurred in formalin-embalmed knees. The posterior horns of the menisci were accessible in all specimens. Conclusion: A medial-lying direct posterior portal into the knee is safe in 99% of occurrences and holds higher clinical viability in terms of accessibility and visibility during arthroscopic procedures. The lateral-lying direct posterior portal is of higher risk to the CFN and is challenging to access arthroscopically.
The effects of aging and tooth loss to the microstructure of the mandible in South Africans
(University of Pretoria, 2022) Oettle, Anna Catherina; Steyn, Maryna; charlotte.theye@gmail.com; Theye, Charlotte E.G.
The mandible plays a crucial role in many biological functions (especially mastication, swallowing and speech) and its efficiency to perform these functions depends on its intactness. Aging and tooth loss are biological processes that may compromise the normal functioning of the mandible by changing its morphology. While many studies address the macroscopic mandibular variations, there is a paucity regarding its microstructure. The aim was to investigate microstructural mandibular changes, with reference to the macrostructure, with advancing age and across various tooth loss patterns in South Africans. As the reasons why individuals are differently affected (extent, rate) by senescence or tooth loss are unclear, the influence of other biological factors (sex, ancestry) was also considered. Using micro-focus X-ray Computed Tomography (micro-CT) scans of 333 mandibles, external dimensions, and inner parameters, namely the cortical thickness (CtTh) and cortical density (approximated by histomorphometric parameters, BV/TV) were measured. To assess whether the mandible ages in the same way and rate as the rest of the skeleton, a comparison of mandibular and femoral cortical BV/TV, using a micro-CT subsample of 68 individuals, was included. A comprehensive assessment of the mandibular morphology and cortical microstructure of fully dentate individuals highlighted that the smaller the alveolar height is, the thicker and denser the cortical bone. An inner cortical asymmetry between basal, buccal, and lingual areas was described for CtTh, but was absent for BV/TV. Sexual dimorphism and ancestral variations were confirmed for the external distances and CtTh, but not for BV/TV. With tooth loss, a general decrease in external distances (aggravated by edentulism), CtTh and BV/TV was observed, except at the midline where the lingual CtTh increased with edentulism. Sexual dimorphism and ancestral variations of the external dimensions and CtTh were emphasised in edentulous mandibles. The cortical density decreased with aging, corroborating the general decline in bone mass of the skeleton, as noted in the femur. By contrasting the effects of tooth loss and aging, it was concluded that both external distances and CtTh were mainly influenced by tooth loss and not age, whereas the cortical bone density displayed an age-related decrease independent of tooth loss. To ascertain the applicability of the findings in a dental setting, where Cone-Beam Computed Tomography (CBCT) is commonly used, measurements were performed on 24 mandibles scanned by both CBCT and micro-CT (considered as the reference). The accuracy and repeatability of CBCT was confirmed for large-scale measurements, and CtTh in a lesser manner, whereas results were uncertain for BV/TV, revealing a distinct lack of reliability. In conclusion, this thesis inferred the precise role of aging and tooth loss, but also sex and ancestry, on the variations of the mandibular macro- and microstructure. Not only does knowledge and understanding of these changes have implications in dentistry fields, as cortical thickness and density are essential for many dental procedures; but also in biological anthropology, in which the microstructure of extant human mandibles gives valuable insights into intra- and interspecific variations (e.g., sexual dimorphism), or functional considerations (mastication, diet) of archaeological/fossil specimens.
Establishing the safe use of the Bridging Infix method for anterior pelvic fixation in a South African sample
(University of Pretoria, 2022) Mogale, Nkhensani; Keough, Natalie; jerolizevs@outlook.com; Van Schalkwyk, Jerolize
The Bridging Infix was proposed as a novel minimally invasive technique for anterior pelvic fixation. The novel method was proposed with the objective of reducing known complications of the established INFIX or Pelvic Bridge techniques. The complications encompass lateral femoral cutaneous nerve (LFCN) impingement, femoral nerve palsy, spermatic cord compression, heterotopic ossification, and patient discomfort leading to explant and neuropraxia. With regard to the placement of the Bridging Infix, it was hypothesized that structures in the vicinity of the ASIS would be at risk and therefore were considered in the current study. Additional and more pertinent distances to the implant were also needed in order to establish the safety of the Bridging Infix in this reference sample. Currently the LFCN is the most prevalent structure of concern mentioned in publications relating to anterior pelvic fixation. When comparing the Bridging Infix to the established techniques, it was found that the LFCN can be considered to be a safe distance from the cortical screws when they are directly inserted into the iliac crest. The LFCN was found to be a minimum distance of 18.40 mm medial to the most proximal cortical screw. In the current study, no other surrounding anatomical structure, namely the iliohypogastric nerve, ilioinguinal nerve, superficial epigastric vessels, superficial circumflex iliac vessels, femoral vein, femoral artery, femoral nerve or spermatic cord were found to be injured as a result of the implant procedure. Literature has described various surgical risks associated with subcutaneous anterior fixation; which include compression concerns and injury to both the LFCN and femoral nerve. The femoral neurovasculature lie deep to the subcutaneous tunnel and inguinal ligament and are therefore at minimal risk of injury. The closest distance of the femoral nerve to the ASIS was 35.74 mm on the right of one specimen. Anatomical venous variations are known to have a high prevalence and thus are widely reported. During dissection, a unique variation, relating to the course, size, and shape of the superficial external pudendal vein was noted. The superficial external pudendal vein anastomosed on the midline of the anterior abdominal wall and coursed in a tortuous manner across the anterior abdominal wall to the proximal thigh. The diameter of the vessel ranged between 3.01 mm – 7.75 mm which is much larger than reported in literature. Although the variation of the superficial external pudendal vein is an anomaly, surgeons should still be mindful of this during surgical procedures involving the anterior abdominal wall to circumvent bleeding complications. In conclusion, the Bridging Infix procedure can be considered safe if layer by layer dissection is employed, the screws are directly inserted on the iliac crest, and the musculature is properly retracted during the lateral window dissection, with no pressure being applied within three finger breadths medial to the ASIS. These results are of interest to orthopaedic surgeons operating to reduce pelvic fractures using a minimally invasive technique. These results could assist in reducing post-operative complications following anterior pelvic fixation.
Anatomical investigation of the accessory nerve
(University of Pretoria, 2021-12) Venter, Gerda; Roode, Giel; Prigge, Lané; u14118883@tuks.co.za; Harangee, Jayshree
The eleventh cranial nerve, known as the accessory nerve (CN XI), consists of a cranial and a spinal component. The spinal root is responsible for the motor innervation of the sternocleidomastoid (SCM) muscle and the trapezius (TZ) muscle. During neck dissection, shoulder syndrome presents in patients due to the injury of the CN XI, which inadvertently leads to the paralysis of the SCM muscle and TZ muscle. The specific function of the CN XI is not well-known as the anatomy described in the literature is inconstant, and variation is found with regard to the anastomotic connections with other nerves. The purpose of this research was to investigate the anatomical description of the CN XI in the posterior triangle, as well as its possible connections to the posterior root of the first cervical nerve (C1). Ten cadaveric spinal cord specimens were used in the examination of the CN XI's possible connections to other nerves, and 38 adult embalmed cadavers were used in the investigation of the CN XI's course through the posterior triangle of the neck. The results obtained indicated that the spinal root of the CN XI arises mainly from rootlets of C1 to C5 spinal nerves. The most common variation found was the posterior root of C1 spinal nerve joining the CN XI and ending at the point of anastomosis (Type IV). This type of anastomosis was seen in four cadavers (40%) on both sides and this connection type was found more in males than in females. Using the average lengths of the SCM muscle and TZ muscle to divide the posterior triangle into a superior, middle and inferior third it was found that nerve mainly coursed from the middle third of the SCM muscle to the inferior third of the TZ muscle in 32/76 (42.11%) specimens and this was seen more in males than females. From the data collected, the nerve's position, course, and branching were not statistically significant (p>0.05) when compared to sex (male and female) and side (left or right) of the cadaver. However, it was found that using the superior borders of the sternal and acromial ends of the clavicle can be used to narrow down the entry and exit points of the CN XI. There was also a high intra/inter-rater reliability for the measurements using the clavicle as a bony vi landmark. However, when using the soft tissue landmarks, the measurements varied significantly between the observers. Based on the results from the present study there is great variability of interconnections with the CN XI found in the posterior triangle and spinal cord. These anatomical findings can attempt to explain why function loss may also vary in different patients when the CN XI is injured. Due to the great variation found within the CN XI's origin, course and function this study concludes that when conducting surgical neck dissection, one should avoid removing any nerve, including the cervical plexus nerves. Keywords: Accessory nerve, Clavicle, Erb’s point, First cervical spinal nerve, Nerve of McKenzie, Spinal accessory nerve palsy, Sternocleidomastoid, Trapezius
A geometric morphometric study on variations in the hard and soft tissue auditory matrices of South African populations
(University of Pretoria, 2021) Ridel, A.F. (Alison); L'Abbe, Ericka Noelle; meg-kyla.erasmus@up.ac.za; Erasmus, Meg-Kyla
The ear is a complex structure that has been mostly ignored in facial approximation. Thus, information is limited on how to reliably estimate its shape for craniofacial approximations. Current manual facial approximation methods employed in South Africa use standard ear casts, with no consideration of the influence of sex, age, and ancestry on the morphological structure of the ear. As the field of facial approximation moves towards automated and computerised methods, more studies are being aimed at developing sex-, age-, and ancestry-specific databases. This study aims to assess variations and associations in ear shape and the eyes, nose, and mouth; and the underlying hard tissues of the external auditory meatus (EAM), nasal bones, nasal aperture, orbits, zygoma, and maxilla, in a sample of 40 black South Africans and 76 white South Africans between the ages of 18 and 90 years of age. A total of 50 capulometric and 43 craniometric landmarks were automatically placed on a sample of Cone Beam Computed Tomography (CBCT) scan reconstructions using MeVisLab 2.7.1. A further 559 semi-landmarks were automatically placed along the curves of the EAM, orbits, and anterior nasal aperture. The cartesian coordinates were recorded and analysed using geometric morphometric methods (GMM). General Procrustes Analysis (GPA), Principal Component Analysis (PCA), and multivariate normality testing were performed on all hard and soft tissue matrices for the entire sample, and each ancestral group separately. Both hard- and soft-tissue auditory matrices resulted in statistically significant asymmetry (p-value = 0.007). Thus, left and right matrices for the ears and EAM were assessed individually. Statistical analysis performed using MANOVA, revealed highly significant variation in ear shape between groups for ancestry (p-value = 0.001), while sex and age were only significant between the white South African sub-sample (p -value < 0.05). The influence of ancestry in EAM shape was also found to be highly significant (p-value = 0.001), with sex only significantly influencing the right EAM and age not being significant. Size was only found to significantly influence shape on the auditory hard-tissues and not the soft-tissue ear. Strong positive correlations were observed between the soft-tissue ear and EAM (r2 > 0.7). The ear was also tested for correlations against other facial features, with strong positive correlations observed between shapes of the ear and orbit, mid-facial matrix, and nose – iv which is the facial feature most cited in the literature as the base of understanding for estimating the size and shape of the ear. The results of this study support the use of automatic landmarking procedures to collect data on large samples, and the accurate placement of sliding landmarks will allow a better understanding of the shape of curves. Variations between groups indicate a need for population-specific databases for estimating the shape of the ear in South Africa. When estimating the shape of the ear, other facial features should be considered and factors such as the influence of ancestry included in the approximation. Sex and age will be of lesser concern when creating predictive models, as well as the influence of allometry.
A comparison of arterial measurements between a South African cadaver and living sample as affected by age, sex, height and weight
(University of Pretoria, 2020) Van Schoor, Albert-Neels; Du Toit, Peet J.; naude.marelize@hotmail.com; Naude, Marelize
Knowledge of the normal arterial diameter at a given anatomical point is the first step towards quantifying the severity of cardiovascular diseases. According to several studies, parameters such as age, weight, height, Body Mass Index and sex, can explain morphometric variations in arterial anatomy. There is no specific differentiation point between normal age-related arterial changes and pathological changes. Therefore, it remains challenging to distinguish between physiological and pathological processes as structural changes in arteries are bound to occur with the advancement of age. There is no point at which an artery can be said to have stopped growing or developing and started to degenerate or becoming diseased. Hence the knowledge of changes in arterial anatomy with age is vital for understanding arterial pathology. Arterial dimensions studied by other researchers were measured on cadaveric material or diagnostic imaging methodologies such as magnetic resonance imaging, computed tomography and ultrasound. The comparability and compatibility of cadaveric and image diagnostic methodology measurements has often been fiercely debated; repeatedly raising the question on the validity of cadaveric research. The primary purpose of this study was thus to compare the measurements taken on cadaveric material with measurements taken with computed tomography and ultrasound. The aim was to establish whether there is a statistically significant difference between arterial measurements taken via these different approaches. In addition, the study also aimed to examine the effects of various demographic parameters on the arterial diameters of a South African population. Digital arterial measurements were taken on computed tomography images at selected arterial sites and the age and sex of each individual were noted. These computed tomography images, representative of a living South African population, were retrospectively selected from the database of diagnostic images at the Department of Radiology, Steve Biko Academic Hospital. The arterial diameter at the identified arterial sites was measured with the assistance of computer software. Digital measurements of arteries on ultrasound images were also measured at the selected arterial sites and the age, sex, weight, height and Body Mass Index of each individual were noted or calculated. Ultrasound images were taken on volunteers in the Department of Anatomy, University of Pretoria. Demographic information, including age, sex, weight and height, was gathered via a paper-based questionnaire. Body Mass Index was calculated. Newly available cadaveric data was added to the cadaveric database compiled during two pilot studies that took place in the Department of Anatomy at the University of Pretoria. The collected data allowed for the comparison of diameters measured with the different methodologies. The South African sample was divided into comparable age and sex groups that also allowed for the determination of correlations between the changes in arterial diameters and the changes in the demographic parameters. Analyses of these correlations answered questions such as whether arterial diameter increase or decrease with an increase in age, height or weight. This study found that age is a vital demographic parameter when assessing change in arterial dimensions. Age was also found to influence muscular and elastic arteries differently. Even though some sexual dimorphism was noted, sex had a significantly smaller effect on arterial dimensions compared to age. Weight, height and BMI correlated weakly with a change in arterial dimension. Comparisons between the different populations indicated that cadaver measurements compared well to CT measurements as well as ultrasound measurements, but that CT measurements and ultrasound measurements were significantly different. Arterial pathology is a major contributor to cardiovascular disease and mortality. Data on normal arterial dimensions for a South African population is scarce, but essential when evaluating whether a dilatation or stenosis are pathological. Studies on the arterial morphology on a cadaver sample are thus comparable to living populations and support the premise that there is an age-related increase in the dilatation of the arterial lumen. The arterial diameter is a useful indicator of the vascular ageing process. This study provided us with valuable information regarding the validity and comparability of several arterial measuring methodologies as well as vital information regarding arterial changes in a South African population.
A multidisciplinary approach to investigate the manifestations of Diffuse Idiopathic Skeletal Hyperostosis (DISH) in modern South African skeletal remains
(University of Pretoria, 2020) L'Abbe, Ericka Noelle; Steyn, Maryna; rachelholgate@hotmail.com; Holgate, Rachel Lucy Victoria
Diffuse idiopathic skeletal hyperostosis (DISH) is a pathological condition that primarily affects the spine. The focus of this study was to investigate the possible link between a diet rich in animal proteins and DISH using carbon and nitrogen isotope analysis, while also making observations on the development and underlying structure of the spinal manifestations of individuals diagnosed with DISH using micro-computed tomography (micro-CT). This investigation into DISH was undertaken in three steps. Firstly, a macroscopic analysis of DISH was conducted to identify individuals diagnosed with DISH according to accepted diagnostic criteria from three cadaver-derived South African skeletal populations (including the Pretoria Bone Collection, The Raymond A. Dart Collection of Human skeletons, and the Kirsten Collection of Human remains). Secondly, stable isotope ratios (δ¹3C and δ¹⁵N) were measured from human bone collagen samples (rib and femur), to investigate the relationship between diet and DISH, specifically a diet high in animal protein. The isotopic values (δ¹3C and δ¹⁵N respectively) were compared for both the rib and femur samples jointly and separately, between the DISH group and a control group, to see if differences existed according to sex, ancestry, BMI, BMI and ancestry combined and collection source. Thirdly, the underlying structure associated with the calcification/ossification associated with DISH (in the spine) was assessed using micro-CT scanning. Across all three skeletal collections, 127 (77% male and 23% female) individuals had characteristics associated with DISH (3.3%), with no difference in prevalence between males and females. DISH was found to be most prevalent among white South African males, indicating something (perhaps genetic or cultural) within the group, giving rise to their propensity to developing the disease. No association between BMI classification and prevalence of DISH was found. Stable isotope analysis indicated that while individuals with DISH generally had elevated δ15N values, but δ15N was also high among the control group, with both groups displaying a mean of 13.0‰. Most black South Africans diagnosed with DISH were enriched in δ¹3C, but relatively depleted in δ¹⁵N, while the white and coloured South Africans showed a positive correlation between δ¹⁵N enrichment and δ¹3C enrichment. Within the DISH group, overweight individuals were generally more enriched in δ¹⁵N and depleted in δ¹³C, while the underweight individuals were more enriched in δ¹³C and depleted in δ¹⁵N. The isotope analyses presents a complex narrative between diet and DISH. While elevated δ15N values among individuals diagnosed with DISH could be interpreted as consumption of animal protein, it was not exclusive to those with DISH and was also noted in non-DISH individuals. Any variations in the δ¹3C and δ15N values found between the DISH and control groups are most likely reflecting different dietary patterns, associated with temporal changes, cultural practices, religious and economic factors, independent of DISH. Observations from the micro-CT scans corroborate some of the clinical interpretations within the literature, such as flowing ossification being limited to the right lateral portion in the anterior aspect of contiguous vertebrae (except in one case where situs inversus was a possibility) and retention of the intervertebral disc space. In contrast to the literature, a possible erosive/inflammatory process was noted in the spinal development of DISH, preceding new bone formation. This was characterised by the destruction of the original vertebral wall underneath the fluid ossification/new bone formation. In summary, the finding from the micro-CT scans is worth further exploration in future research, while the isotopic analysis lends no support to the theory that the presence of DISH is associated with a diet high in protein.
The anatomical description of the erector spinae, paravertebral and epidural block for post-operative pain management in paediatric care.
(University of Pretoria, 2020-01) Van Schoor, Albert-Neels; Bosenberg, A.T.; u11083647@tuks.co.za; Govender, Sabashnee
Summary The anatomical description of the erector spinae -, paravertebral - and epidural block for post-operative pain management in paediatric care S Govender Supervisor: Prof AN van Schoor Co-supervisor: Prof AT Bosenberg Department of Anatomy: Clinical Anatomy, School of Medicine, Faculty of Health Sciences, University of Pretoria, South Africa The fundamental indicative constituent for any successful clinical procedure is patient satisfaction, which is directly related to post-operative analgesia. In paediatric care, due to the nature of the patient – and depending on the age group – it is often difficult, or even impossible, to fully understand the extent of pain perceived, leading to insufficient pain management. A variety of regional anaesthetic techniques have been thoroughly investigated for the ease of administration, as well as enhanced patient satisfaction. Coupled with image modalities, these blocks can be safe and efficient. However, these investigations mainly apply to an adult population. Paediatric procedures may be inaccurately extrapolated from an adult population, when the anatomical discrepancies that exist between population groups are not taken into consideration. Until recently, the gold standard for paediatric truncal procedures relied solely on paravertebral and epidural blocks. With the discovery of the novel interfascial erector spinae plane block, however, this is no longer the case. This block is hypothesised to target the ventral and dorsal rami of spinal nerves, as local anaesthetic is deposited into the erector spinae fascial plane space. The therapeutic effect of the block is attributed to the cranio-caudal spread of anaesthetic over multiple vertebral levels within the tissue plane. This ‘happily accidental’ block serves as a “paravertebral block by proxy” and is an alternative approach, targeting similar nerves as in the paravertebral and epidural blocks. However, the anatomy of the erector spinae plane block is not fully understood. This study aimed to investigate the anatomical differences of these three blocks for the management of post-operative pain in paediatric care, based on observations and measurements from a fresh paediatric cadaver sample, as well as ultrasound and computed tomography scans. Apart from the easily identifiable bony landmarks, together with the distant application of the erector spinae plane block, the block offers a higher safety profile with various clinical advantages such as improved pre- and post-operative pain management, as well as reduced opioid requirement. In conclusion, it is vital to acknowledge the anatomical differences that exist in a paediatric population for the safe and successful administration of any regional technique to improve the management of pain in a vulnerable population. Keywords: Erector spinae plane block, paravertebral block, epidural block, interfascial block, paediatric, regional anaesthesia, pain management

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