Anatomical variation of the carotid bifurcation in a Stellenbosch University cadaver cohort

Dreyer, Rita Liezl (2019-04)

Thesis (MSc)--Stellenbosch University, 2019.

Thesis

ENGLISH ABSTRACT: The carotid bifurcation is the point where the common carotid artery bifurcates into the internal and external carotid artery. A precise anatomical knowledge of the carotid bifurcation is required for various medical specialities. The anatomy of the carotid bifurcation influences the risks, location and prognosis of related pathology. Furthermore, the anatomy of the carotid bifurcation affects treatment as it determines which surgical techniques can be used in an area of high risk. The aim of the study was to determine the anatomical variations of the carotid bifurcation in a Stellenbosch cadaver cohort. One hundred and twenty-eight specimens were examined. This research focuses on the height, angle, general structure, and diameters of the carotid bifurcation, as well as the length and diameter of the carotid sinus. The internal anatomical variation of the carotid bifurcation was added as the study progressed. This study used the gonion as the landmark when measuring height. The Stellenbosch cadaver cohort had a high frequency of high bifurcation with the mean distance of 2.12 cm on the right and 2.06 cm on the left. The angle of bifurcation was 18.53° on the right and 20.24° on the left and was smaller than previous reports in the literature, which ranged between 51-67°. Females had a higher bifurcation and larger angle of bifurcation than males. Sex affected the correlation between angle and height of the bifurcation. The general structure correlated with the standard description and was not influenced by other factors pertaining to the carotid bifurcation, sex or age. Kinks were found in the internal and external carotid artery. The diameters of the carotid bifurcation were larger on the left than on the right. The height of the bifurcation did not influence the probability of kinks in this study, contrary to the literature. The diameters of the internal, external and common carotid arteries in addition to the carotid sinus diameter were larger on the left side and in males. The external carotid had the weakest correlation with the other diameters, which was due to the external carotid artery’s embryological origin. The length of the carotid sinus was 1.74 cm on the right and 1.83 cm on the left. The diameters and the length of the carotid sinus was larger in the males. All external variation slightly increased with age over time as the elasticity of arteries decreased. A variation of the flow diverter was observed in 59% of the cadaver cohort. Supplementary flow diverters were a rare abnormality observed in the internal, external and common carotid arteries. The reason for the carotid bifurcation to present with supplementary flow diverters is still up for debate as this has not been observed in living patients; however, a pathological origin was suggested. Folds in the common carotid were observed. Internal anatomical variation was not affected by external variation or age; however, men had a higher probability of presenting with variation. The Stellenbosch cadaver cohort illustrated variations in the carotid bifurcation which was population-specific. Sex influenced various aspects and correlations of the carotid bifurcation, which means discrepancies can occur and should be considered. Further studies on the carotid bifurcation are needed.

AFRIKAANSE OPSOMMING: Die karotis bifurkasie is die punt waar die gemene karotis arterie verdeel in die interne en eksterne karotis arteries. Presiese anatomiese kennis van die karotis bifurkasie is nodig vir verskeie mediese spesialiteite. Die anatomie van die karotis bifurkasie beïnvloed die risiko's, van ligging en prognose van patologie. Verder, anatomie van die karotis bifurkasie afeckteer behandeling as dit bepaal watter chirurgiese tegnieke gebruik moet word in 'n area van hoë risiko. Die doel van die studie was om die anatomiese variasies van die karotis bifurkasie te bepaal in 'n Stellenbosch kadaver groep. Een honderd agt-en-twintig kadawers was ondersoek. Hierdie navorsing fokus op die hoogte, die hoek, algemene struktuur, en deursnee van die karotis bifurkasie asook die lengte en deursnee van die karotis sinus. Die interne anatomiese variasie van die karotis bifurkasie was by gevoeg later in die studie. Hierdie studie gebruik die gonion as die landmerk baken om die hoogte te meet. Die Stellenbosch kadaver groep het 'n hoë voorkomsvan hoë bifurkasie met n gemiddelde afstand van 2.12 cm aan die regterkant en 2.06 cm aan die linkerkant. Die hoek van bifurckasie was 18.53° aan die regterkant en 20.24° aan die linkerkant en was heelwat kleiner as vorige literatuur. Vroue het hoër bifurkasie en groter hoeke van bifurkasie as mans getoon. Seks bewerkstellig die korrelasie tussen hoek en hoogte van die bifurkasie. Die algemene struktuur gekorreleer met standaard beskrywing en was nie beïnvloed deur ander faktor met betrekking tot die karotis bifurkasie, geslag of ouderdom. Kronkels is gevind in die interne en eksterne karotis arterie. Die deursnee was groter aan die linkerkant as aan die regterkant. Hoogte van die bifurkasie het nie die waarskynlikheid van kronkels in hierdie studie beinvloed nie in teenstelling met wat die literatuur se. Die deursnee van die interne, eksterne en algemene karotis arteries benewens die karotis sinus deursnee was groter aan die linkerkant en by mans. Die eksterne karotis het die swakste korrelasie met die ander diameters, en is die gevolg van sy embriologiese oorsprong. Die lengte van die karotis sinus is 1.74 cm aan die regterkant en 1.83 cm aan die linkerkant. Die deursnee en die lengte van die karotis sinus was groter by die manlike kadawers. Alle eksterne variasie neem effens toe met ouderdom as gevolg van die elastisisteit wat verminder. Variasie van die vloei-herleiers was in 59% van die studie groep waargeneem. Aanvullende vloei herleier was 'n seldsame abnormaliteit waargeneem in die interne, eksterne en algemene karotis areries. Daar is tans geen opvallende rede vir die karotis bifurkasie se aanvullende vloei herleier nie. Verdere navorsing word steeds benodig om te bevestig of hulle waargeneem word in lewende pasiënte. Daar word voorgestel dat die karotis bifurkasie se anvullende vloei herleier van patologiese oorsprong is. Voue in die algemene karotis was waargeneem. Interne anatomiese variasie is nie beïnvloed deur eksterne variasie of ouderdom, maar seks het geïllustreer dat mans het 'n hoër waarskynlikheid van voorkoms van die variasie Die Stellenbosch kadaver groep geïllustreer variasie in die karotis bifurkasie wat bevolking spesifieke is. Geslag beinvloed die verskillende aspekte van die karotis bifurkasie wat beteken teenstrydighede kan voorkom indien dit nie in ag geneem word nie, nie oorweeg. Verdere studies is nodig op die karotis bifurkasie.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/105882
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