Browsing by Author "Louw, Graham J"

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    An investigation into variations in the venous drainage pattern in brains of adolescents and adults
    (2020) du Toit, Francesca; Louw, Graham J
    It is well established that the brain changes dramatically in appearance during gestation and even after birth. Due to the multi-channelled origins and the number of developmental options, the adult venous system is characterised by a higher incidence of anatomical variations than the arterial system. Limited information is available on anatomical variation of the complete cerebral venous system. It is important to have an understanding of the usual drainage pattern the cerebral venous system and its anatomical variations to provide a foundation for future studies on anomalous venous structures. The extent to which fetal drainage patterns persist postnatally has yet to be established. The goal of the current study was to accurately describe the cerebral venous drainage patterns, including persistence of fetal drainage patterns in children, adolescents and adults in order to understand anatomical variations and the clinical impact during cerebrovascular interventions. For the current study 302 magnetic resonance images with contrast medium from the Groote Schuur and Red Cross Children's War Memorial Hospitals were retrospectively reviewed. The volumes of the dural venous sinuses were traced using a novel approach developed for the study. The approach included constructing 3D models of the dural venous sinuses and using the tracings for statistical and morphological analyses. No images of children met the inclusion criteria and therefore further analyses of the subset was not possible. Statistical analyses were performed to determine if there are any associations between venous sinus volume and sex, age, cerebral dominance and/or variations. Significant differences were noted for sex, dominance and variations of the cerebral venous system. The confluence of sinuses (CS) showed the most abundant number of variations. Although many studies and classifications have been made regarding the variations of these structures, there is a lack of a comprehensive classification that includes all variations. The goal of the current study was to determine the anatomical variations more comprehensively particularly at the level of the superior sagittal sinus (SSS) and confluence of sinuses. The study improved on the current literature by using contrast enhanced images as opposed to nonenhanced images or results obtained at autopsy. It is also the first study to establish a tracing protocol for venous volume to determine cerebral dominance and describe variations of the dural venous sinuses.
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    An ultrasonographic analysis of the activation patterns of abdominal muscles in children with spastic type cerebral palsy and in typically developing individuals: a comparative study
    (BioMed Central, 2018-06-05) Adjenti, Saviour K; Louw, Graham J; Jelsma, Jennifer; Unger, Marianne
    Abstract Background Abdominal muscles have stiffer appearance in individuals with spastic type cerebral palsy (STCP) than in their typically developing (TD) peers. This apparent stiffness has been implicated in pelvic instability, mal-rotation, poor gait and locomotion. This study was aimed at investigating whether abdominal muscles activation patterns from rest to activity differ in the two groups. Method From ultrasound images, abdominal muscles thickness during the resting and active stages was measured in 63 STCP and 82 TD children. The thickness at each stage and the change in thickness from rest to activity were compared between the two groups. Results Rectus abdominis (RA) muscle was the thickest muscle at rest as well as in active stage in both groups. At rest, all muscles were significantly thicker in the STCP children (p <  0.001). From rest to active stages muscle thickness significantly increased (p <  0.001) in the TD group and significantly decreased (p <  0.001) in the STCP children, except for RA, which became thicker during activity in both groups. In active stages, no significant differences in the thickness in the four abdominal muscles were found between the STCP and the TD children. Conclusion Apart from the RA muscle, the activation pattern of abdominal muscles in individuals with STCP differs from that of TD individuals. Further studies required for understanding the activation patterns of abdominal muscles prior to any physical fitness programmes aimed at improving the quality of life in individuals with STCP. Trial registration HREC REF: 490/2011 . Human Research Ethics Committee, Faculty of Health Sciences, University of Cape Town, South Africa. November 17, 2011.
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    An assessment of muscle insertion sites and biomechanical beam analaysis in living subjects
    (2001) Sanders, Virginia M; Morris, Alan G; Louw, Graham J; Constant, Deborah A
    The main aim of this study is to examine the gross morphology of the radial tuberosity, brachialis insertion site and supinator crest in living subjects, and to correlate this with muscle strength.
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    An investigation into the value of supplementing dissection of the human body with alternative resources: Perceptions of students and staff at the University of Cape Town
    (2017) Ramgoolam, Shakira; Louw, Graham J
    The purpose of this study was to explore the perceived value of supplementing the traditional cadaver dissection course at the University of Cape Town's Faculty of Health Sciences (UCT FHS) with alternatives in order to aid students in their learning of anatomy. The study aimed to collect information which could be used to provide insight into facilitating a deeper educational experience for students and teachers alike in the future with the aim of better retention of knowledge over time. The intention of the study was to obtain results which could potentially provide insight into the feasibility of adopting a contemporary view on anatomy education at UCT FHS and thus inform the anatomy course in the future by acquiring feedback directly from the students and staff of the university. Data was collected by way of a 22 question survey delivered to second to sixth year MBChB students as well as the staff and postgraduate students at UCT FHS. The survey was entirely voluntary. A total of 190 complete responses were collected. The results of the study indicate that both staff and students feel that the cadaver dissection course is an irreplaceable part of the curriculum, and if the faculty chose to use any technological alternatives to teach anatomy, that they should supplement and not replace traditional dissection. Furthermore, the study showed that the staff and students are comfortable with technology in general, and are open to the use of various technologies such as online material, virtual software, media sites, applications and the like in order to bolster their learning. These results may provide insight into the viability of adopting a contemporary view on anatomy education at UCT FHS and may thus inform changes to the anatomy curriculum in the future.
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    Lumbosacral transitional vertebrae morphology: a South African population
    (2021) Paton, Glen James; Louw, Graham J; Williams, Scott A; Nalla, Shahed
    Lumbosacral transitional vertebrae (LSTV) are defined as congenital anatomical variations, observed unilaterally or bilaterally, in which the transverse process of the last lumbar vertebra exhibits signs of dysplasia evident as increased craniocaudal height, with varying degrees of articulation or fusion to the ‘first' sacral vertebra. Such variations give rise to vertebral morphology that may display lumbar or sacral characteristics at the terminal lumbar spine, together with subsequent enumeration variation. The purpose of this study was to establish baseline data on the prevalence rates of LSTV and to describe the morphological characteristics (Type, subtype, frequency of side and spinal enumeration) of LSTV in the South African population. This study was subdivided into two main sections, namely Part 1: medical imaging appraisal and Part 2: osteological morphology appraisal. In Part 1, both retrospective and prospective cohort randomised sampling methods of data collection of medical images were used. The appraisal of the medical images included radiographs, magnetic resonance imagers and computerised tomography scans. Prevalence rates, utilising the Castellvi et al. (1984) classification, were established via radiographs only. Additionally, lumbar spine enumeration, namely lumbarisation and sacralisation, was made through the appraisal of lumbar radiographs. Images were obtained from medical radiology practices located at Groote Schuur Hospital in Cape Town, Western Cape Province and Charlotte Maxeke Johannesburg Academic Hospital in Johannesburg, Gauteng Province. The total imaging cohort included 3096 individuals of which 308 individuals (10%) were found to contain LSTV. Prevalence rates were further evaluated by subdivision of the three largest ancestries in South Africa. Ancestries were classified as African (n=1032), Mixed (n=1032) and European (n=1032). The prevalence of LSTV in the three ancestral groups was 10.5%, 9.3% and 9.9% respectively and the sex distribution was greater in females (52.1%) then in males (47.9%). The morphological assessment found the prevalence of LSTV by Type was Type II (67.9%) followed by Types III (27.6%) and IV (4.5%). The most frequent subtype by prevalence was Type IIA (41.9%) followed by Type IIB (26%), Type IIIB (21.8%), and Type IV (5.8%). Additionally, the frequency of side was bilateral (47.7%), left (26.6%), right (21.1%), and other (4.5%). Comparison of ancestry and spinal enumeration analyses established statistical significance for individuals of African-ancestry (67.0%) and Mixed-ancestry (72.9%) both of which demonstrated a greater affinity of prevalence for sacralisation (p=0.008), with a small effect size (V=0.178) over the European-ancestry subgroup (52.4%). Furthermore, a statistical significance with a medium effect size (V=0.256) was found in males (p=0.010) when comparing ancestry and spinal enumeration between sexes. In Part 2, a systematic search of the total cadaveric skeletal collection housed at the University of Witwatersrand (the Dart Collection of skeletons) yielded 1797 human skeletal specimens of between 21 and 65 years of age at time of death. One-hundred and fourteen skeletal remains were identified as containing LSTV. Damage and loss of vertebral elements resulted in a subset of 91 LSTV for study. A sex balanced control group cohort of 30 males and 30 females was selected at random from the Dart Collection for comparative analyses. A number of osteometric measurements were evaluated comparing the LSTV and control group cohorts. Numerous osteometric comparisons were statistically significant highlighting the many changes in lumbar and sacral morphology associated with LSTV. There are several original findings to emerge. Thisis the first study to establish the prevalence of LSTV in a large sample from the South African population, subdivided into the three largest ancestral groups. Novel findings associated with LSTV include iliolumbar articulation, bipartition of the sacral foramen, intra-articular vacuum phenomenon of accessory articulations of LSTV, enlargement of the contralateral TVP associated with Types III and IV LSTV, lumbar ossified bridging syndrome and a novel complex named by the researcher as the transverso-sacro-iliac articulation. Furthermore, the researcher has proposed three modifications to the Castellvi et al. (1984) classification, namely (1) that there should be a sub-classification of the Type IV LSTV into right and left nomenclature, (2) the inclusion of a new subtype of Type II LSTV morphology, a unilateral right or left iliolumbar articulation associated with contralateral Type IIA morphology, and (3) a modified morphological classification of LSTV based on the presence of an extended sacroiliac articulation either directly or via the transverso-sacro-iliac articulation. The latter effectively increases the size of the sacroiliac joint and is thought to increase spinopelvic stability. The transverso-sacroiliac articulation was demonstrated for all clinically significant LSTV Types (II-IV), both unilateral (right or left) and bilateral. Finally, this is the first study to incorporate an in situ and an ex situ study in the same population by examining spinal morphology of LSTV using medical images and skeletal remains for descriptive analyses.
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    Variations in arterial supply via the external and internal carotid arteries to the bony orbit and eyeball in full-term fetuses, infants, children, adolescents, and adults – a South African perspective
    (2022) Mpolokeng, Kentse Sana; Louw, Graham J; van der Merwe, Elizabeth
    The anatomy of the orbital region is of great importance for many highly specialised clinical disciplines such as ophthalmology, maxillofacial surgery, and neurosurgery. The main source of arterial blood supply to the orbital region is by the ophthalmic artery, a branch of the internal carotid artery, and to a lesser extent by the anastomotic patterns which are formed through the external carotid artery. A range of arterial variations which may be developmental in origin, or which may develop due to pathologies later in life, may affect the ophthalmic artery in terms of its origin, course, and branching. If clinicians are not aware of the variations occurring in this region, the eye of the patient may be at risk of injury during invasive procedures, which may lead to partial or complete visual loss. Up until the present time, there have been only a few cadaveric studies that revealed some of the variant patterns and the overall frequencies of the recorded anastomotic patterns for the orbital blood supply. Whilst the anatomical variations are known, the frequencies of variations in the population are not. Furthermore, no published data exists regarding the variations in the orbital blood supply in a South African population. Therefore, the aim of this study was to investigate the orbital vascular supply within the South Africans of different age groups, to document and describe any variations in anastomotic patterns and record their frequencies. The current study was conducted through dissections of bodies in the Department of Human Biology, University of Cape Town, and patients' angiograms from Groote Schuur Hospital. The angiograms included data obtained from other hospitals within the Cape Town area and were reviewed retrospectively. The dissection sample included six full term fetuses and 63 adults, and the angiograms accounted for 870 individuals. The ophthalmic artery was studied from the point of origin from the internal carotid artery and its course in relation to the optic nerve, and both sides were compared to note any similarities or differences. Statistical analyses were performed to record the frequencies of the patterns of variations and to note whether there were any associations between sex, age, sidedness, and these variations. The results revealed statistically significant associations between age and sex for the patterns of variation. Several variations were noted in the current study. Among the novel findings were those in the origin of the ophthalmic artery from the internal carotid artery, whereby a lateral and inferior origin were recorded in both samples (dissected bodies and angiograms). In addition, it was noted that the ophthalmic artery may take origin from the A2 segment of the anterior cerebral artery, which is also a novel finding. This study, therefore, adds significantly to the current body of knowledge regarding the patterns of arterial supply to the ophthalmic region in a South African sample.
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    Variations in the insertions of the tibialis posterior muscle and the structure of the medial longitudinal arch
    (2014) Sadler, Maxwell Jennings; Louw, Graham J
    This study utilized cadavers to examine the variable insertions of the tendon of tibialis posterior muscle. Both feet from 29 cadavers were dissected and six variable connections to intrinsic foot structures were documented (frequencies indicated as a per cent): sustentaculum tali (93.1%), abductor hallucis muscle (44.8%), flexor hallucis brevis muscle (22.4%), fibularis longus tendon (58.6%), plantar calcaneonavicular (spring) ligament (17.2%), and the long plantar ligament (34.5%). The frequencies for each variable insertion were also reported individually for sex and population group, as well as the most common combinations of insertions. Measurements describing the medial longitudinal arch of the feet were taken, using a soft tissue intact method (arch index) and the post-dissection method (talus-first metatarsal angle). The insertion data were then compared to the arch measurements, as well as foot side, age, sex, and population group. There was a weak negative correlation between the talus-first metatarsal angle measurement and the presence of an insertion on to sustentaculum tali, as well as a connection to the tendon of fibularis longus. Arch measurements were shown to be statistically significantly similar for left and right feet for each individual. Knowing the arch index on one side of the body allows for an accurate prediction of the arch index on the opposite side within an individual. The right arch index was larger in 55% of the sample. All other correlations were negligible, and the presence or absence of specific insertions was not an accurate predictor of either arch measure. The accumulation of multiple variable insertions did not have any impact on the arch measurements.