Quantitative differentiation of thoracolumbar transitional vertebrae : possible embryological origins and associations with other anomalies in the vertebral column

INTRODUCTION: Transitional vertebrae result from overlapping developmental fields in the spine and can be located at any regional junction in the vertebral column. Consequently, transitional vertebrae retain features from the two respective adjacent regions. Based on the current literature, a need to further investigate TLTV with regards to repeatable differentiation, classification and clinical significance had been identified. MATERIALS AND METHODS: Therefore, this project aimed to identify vertebral anomalies and to determine whether TLTV can be quantitatively differentiated from thoracic and lumbar vertebrae using skeletal remains from Pretoria and the Western Cape of South Africa (n=287). This was achieved by measuring the superior zygapophyseal facet angle. This project also evaluated whether the measuring tool can be applied to living persons. Therefore this study additionally aimed to evaluate whether measurements can be used to differentiate vertebrae at the thoracolumbar junction using CT scans (n=175) representative of the Windhoek population in Namibia. This study also aimed to evaluate whether associations exist among congenital malformations of the spine and to explore the embryological events that lead to the formation of various anomalies in the spine. RESULTS: The results show that the prevalence of TLTV ranges between 7.5% (Windhoek), 30% (Western Cape) and 33.2% (Pretoria) in the reference samples. The results also clearly demonstrate that each vertebral type (thoracic, lumbar, TLTV) falls into separate distributions and confidence intervals. The results show that the mean angles and confidence intervals in skeletal remains for T12 is 189 ±9.5o (CI: 188o-190o), 110.6o ±7.88 (CI: 109.7o - 111.6o) for L1, and 137o ± 24.11 (CI: 133.5o - 140.5o) for TLTV. The mean confidence interval in CT-scans for T12 is 182.8 ± 10.4o (CI: 181.6o-183.9o), 112.3 ± 7.27o (CI: 111.5o-113o) for L1, and 136 ± 23.18o (CI: 125o- 147o) for TLTV. These results infer that each type of vertebra has independent measurable criteria to identify it. High correlation coefficients demonstrated the repeatability of the measurements using skeletal remains (0.94 < r < 0.97) and CT-scans (0.978< r < 0.997). CONCLUSION: The results strongly infer that quantitative morphometry from the superior articular facets of vertebrae can differentiate between T12, L1 and TLTV using radio-images or skeletal remains. This study also concludes that individuals with one defect or congenital malformation in the spine are more likely to have at least one other associated anomaly of the spine.Thesis (PhD (Anatomy))--University of Pretoria, 2021.AnatomyPhD (Anatomy)Unrestricte

Congenital anomalies in the vertebral column associated with thoracolumbar transitional vertebrae

Thesis (MSc)--Stellenbosch University, 2017ENGLISH ABSTRACT : According to Byrd & Comiskey (2016), disrupted ossification during development results in abnormal skeletal development. A study conducted on congenital anomalies by Masnicová & Beňuš (2003), stipulated that most skeletal congenital defects are located in the vertebral column. The most common skeletal defects of the vertebral column are neural tube defects (NTD’s), spondylolysis and cranial-caudal border shifts (Masnicová & Beňuš 2003). In reviewed literature, case studies have reported various congenital defects that are simultaneously present within the vertebral column of an individual. There is, however, a lack of evidence to substantiate whether the mutually inclusive observations resulted by chance, or whether an association between the defects is present. The aim of this study was to determine whether associations exist among random congenital defects in the vertebral column. The objective of this study was to identify and determine the frequency of random congenital defects from a subset of defects in the vertebral column. A selection of skeletal remains were taken (n=35) from a subset in the Kirsten Skeletal Collection at Stellenbosch University. The subset comprised specimens from the population (N=±1100) with congenital defects in the vertebral column that has a reviewed prevalence of 0.5/1000 worldwide. This study hypothesised that there is an association between random congenital defects that results from border shifts or disrupted neural arch formation. The congenital defects considered in the study included: lumbosacral transitional vertebrae (LSTV), thoracolumbar transitional vertebrae (TLTV), spondylolysis, NTD’s and sacro-coccygeal fusion. Descriptive analysis was performed to determine the frequencies of defects in the selection. The descriptive analyses are illustrated in frequency distribution tables for each type of defect evaluated in the study. This study found that every specimen in the selection had TLTV and one or more additional random congenital defect in the vertebral column. Based on the finding, it can be claimed that an association exists between TLTV and other congenital defects of the vertebral column. TLTV were identified based on intermediary characteristics between the thoracic and lumbar regions present in the vertebra. This study concludes that when TLTV is present, it will be associated with one or more random defect in the vertebral column discussed in this study. The association between TLTV and other congenital defects provides an indirect association between all cases where various congenital defects are simultaneously present.AFRIKAANSE OPSOMMING : Volgens Byrd & Comiskey (2016), wanneer ossifisering tydens ontwikkeling ontwrig word, lei dit tot abnormale skelet strukture. 'n Studie wat deur Masnicová & Beňuš (2003) voltooi was het tot die gevolgtrekking gekom dat meeste van die aangebore skeletgebreke in die vertebrale kolom geleë was. Die mees algemene skeletgebreke van die vertebrale kolom word deur ontwikkelingsagterstande van die vertebrale elemente veroorsaak (Masnicová & Beňuš 2003). In die literatuur meld gevalstuddies verskeie aangebore gebreke aan wat binne die vertebrale kolom van individue teenwoordig is. Daar is egter nie genoeg bewyse om te staaf of die waarnemings met mekaar assosieer kan word en of dit toevalig voorgekom het nie. Die doel van hierdie studie was om gebreke van 'n substel van gebreke in die vertebrale kolom vorm te identifiseer en om te evalueer of die gebreke met mekaar assosieer is. ‘n Seleksie van vertebrale kolomme (n = 35) is geneem uit 'n substel groep van die Kirsten skeletversameling by Stellenbosch Universiteit. Hierdie studie het voorspel dat daar ‘n assosiasie tussen verskeie aangebore gebreke in die vertebrale kolom is. Hierdie studie het bevind dat torakale en lumbale oorgangswerwels in al die skelete van die seleksie beskou kon word. Daar was, boonop, ten minste een ander addisionele aangebore afwyking in die vertebrale kolom van elke individu se skelet. Gebaseer op die bevinding, kom hierdie studie tot die gevolgtrekking dat 'n assosiasie tussen tarokale-lumbale oorgangs werwels en ander verskeie gebreke van die vertebrale kolom bestaan