Anatomy

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An anatomical exploration of the extracranial (V1-V3) and intracranial (V4) components of the vertebral arteries in a select KwaZulu-Natal population.
(2021) Omotoso, Bukola Rukayat.; Lazarus, Lelika.; Satyapal, Kapil Sewsaran.; Harrichandparsad, Rohen.
The risk of injury to the vertebral artery is a significant complication of surgery. The presence of anatomical variation in the course of the vertebral artery increases the likelihood of injury. Due to inadequate understanding of the presence and location of anatomical variations in the morphology and morphometry, the vertebral artery can be injured during surgical intervention. Apart from the vascular injury that can occur during surgical intervention, anatomical variations have implications for some pathologies in the posterior circulation territory. These include aneurysm formation, cerebrovascular disorders, posterior circulatory stroke, and some neurovascular problems. In this retrospective observational study, we investigated the anatomical features of the extracranial (V1-V3) and intracranial (V4) components of the vertebral arteries in a South African population. The study is an observational, retrospective chart review of 554 consecutive South African patients (Black, Indian, and White) who had undergone computed tomography angiography (CTA) at Lenmed Ethekwini Hospital and Heart Centre, Durban, South Africa, from January 2009 to September 2019. The vertebral artery exhibited various morphological variations in its course. We report the incidence of variant origin of the left vertebral artery (6.9%). The level of entry into the transverse foramen ranged between C7-C3. We report the incidence of vertebral artery tortuosity at V1, V2: 76.6%, and 32.1%, respectively. We observed fenestration at V3 (0.18%) and V4 (0.4%) segments. We registered the incidence of the persistent first intersegmental artery (1.1%), extradural PICA origin (2.8%), atresia (6.7%), and hypoplastic terminal vertebral artery (13.2%). Average length and diameter at each vertebral artery segment were registered; we also report on hypoplasia of the vertebral artery. Anatomical variations of the vertebral artery are common in the South African population studied in the present study. Imaging of the complete segments of the vertebral artery from the origin to the point of convergence to form the basilar artery may be necessary to decide a treatment strategy for interventions in the vicinity of the vertebral artery. Understanding the patterns of anatomical variations of the vertebral arteries will contribute significantly to the diagnosis of various diseases in the posterior circulatory territory. The average diameter was significantly larger on the left in all the racial groups, but there were no significant gender differences. We registered a left dominance pattern in all the segments (V1-V4). Iqoqa Ingozi yokulimala emithanjeni yomgogodla iyinkinga enzima kakhulu yokuhlinzwa. Ukuba khona kokwehlukahlukana kokwakheka komzimba ekuhambeni komthambo womgogodla kwandisa amathuba okulimala. Ngenxa yokuqonda okunganele kokukhona kanye nendawo yokwehlukahlukana kwesakhikwo somzimba ekwakhekeni nokulinganisa umumo, umthambo womgogodla ungalimala ngesikhathi sokuhlinzwa. Ngaphandle kokulimala kwemithambo yegazi okungenzeka ngesikhathi sokuhlinzwa, ukuhlukahlukana kwemithamdo yomgogodla kunomthelela ngezinye izimbangela ngokuthola umsuka wesifo ngokuhamba kwegazi emigudwini. Lokhu kubandakanya ukwakheka kokuvuvukala komthambo, ukuphazamiseka kokuhamba kwegazi engqondweni, ukushaywa yisifo sohlangothi, nezinye izinkinga ngezinzwa nemithambo. Kulolu cwaningo lokubheka ngokuqhathanisa abanesifo nabangenaso, sibheke ukwakheka komzimba kwamathambo ekhanda ngaphandle (V1-V3) kanye nokwakheka kwawo ngaphakathi (V4) nezingxenye zemithambo yomgogodla emphakathini waseNingizimu Afrikha. Ucwaningo lungukuzibonela ngqo, ukuqhathanisa ngokubuyekeza amashadi eziguli zaseNingizimu Afrikha angama-554 ngokulandelana (abaNsundu, amaNdiya, nabaMhlophe) abafakwe emshinini bahlolwa wonke umzimba ngekhompuyutha ukubona okusemithanjeni (isibonathambomzimba) (CTA) esibhedlela i-Lenmed Ethekwini neSikhungo seNhliziyo, eThekwini, eNingizimu Afrikha, kusukela kuMasingana wowezi-2009 kuya kuMandulo wowezi-2019. Umthambo womgogodla ukhombisa ukwehlukahluka kwesakhiwo ekuthubelezeni kwawo. Sibika isehlakalo semvelaphi esehlukile somthambo womgogodla kwesokunxele (6.9%). Izinga lokungena esikhaleni esiphakathi komthambo womgogodla laliphakathi kwe-C7 ne-C3. Sibika isehlakalo esihambisana nokuguga komthambo womgogodla nomfutho wegazi okulinganiselwa phakathi kuka-V1, V2: 76.6% no-32.1%, ngokulandelana. Sibone ukuhlinzwa kwesakhiwo sendlebe ngaphakathi kwezingxenye ezingu-V3 (0.18%) nezingu-V4 (0.4%). Sabhalisa izehlakalo zomthambo wokuqala ngezingxenye ezilokhu zikhona ngo-1.1%, imvelaphi ye-PICA yamathambo ekhanda (2.8%), isicubu esingenayo embotsheni ngokwemvelo (6.7%), nokungakhuli kwesitho ngokuphelele (13.2%). Isilinganiso sobude nobubanzi engxenyeni ngayinye yomthambo womgogodla yabhaliswa; siphinde sibike ngokungasebenzi ngokwejwayelekile komthambo womgogoda. Ukwehlukahlukana kokwakheka komthambo womgogodla kuvamile kubantu baseNingizimu Afrikha ocwaningweni lwamanje. Ukufanekisa kwezingxenye eziphelele zomthambo womgogodla lapho zihlangana khona ukwenza umthambo ophakathi nendawo ekhanda kungadingakala ukunquma ngamasu okwelapha ngokungenelela endaweni eseduze nomthambo womgogodla. Ukuqonda ukuphiceka kwesakhiwo esahlukahlukene semithambo yomgogodla kuzodlala indima ebalulekile ekuhlonzeni izifo ezahlukahlukene ekuhlinzekweni kokuhamba kwegazi. Isilinganiso sobubanzi besisikhulu kakhulu kwesokunxele kuwo wonke amaqembu ezinhlanga, kodwa kwakungekho mehluko obalulekile phakathi kobulili. Sibhalise indlelakwenza ebihamba phambili kuzo zonke izingxenye ebe ngu-V1-V4.
An anatomical investigation of intracranial meningiomas.
(2021) Anirudh, Ezra Earl.; Lazarus, Lelika.; Harrichandparsad, Rohen.
Meningiomas are generally benign, highly vascularised, slow-growing tumours arising from the arachnoid cap cells of the arachnoid villi. The clinical presentation of these tumours is usually location dependant due to the vast expanse covered by the meninges. Resection of a meningioma is generally performed after preoperative embolisation. A feeder vessel is selected and embolised in an attempt to reduce excessive blood loss and postoperative complications. However, embolisation requires a sound knowledge of the vasculature of the meninges since these vessels supply portions of the cranial nerves. Literature consulted have investigated anatomical features of meningioma’s; however, there is a scarcity of studies investigating patients specifically referred for preoperative embolisation. Therefore, this study aimed to investigate the anatomical features, namely the location, histology, volume and vascularity of intracranial meningiomas referred for preoperative embolisation. This entailed using Magnetic resonance imaging (MRI), Digital subtraction angiography (DSA), and the histological reports obtained from the data bank at the central regional hospital in Durban, South Africa. A retrospective chart review yielded 103 patients that met the inclusion criteria, of which 98 patients (subset 1) presented with a single meningioma and 5 patients (subset 2) presented with multiple meningiomas. The average age of patients (at the time of diagnosis) was reported within the 40–49-year group and primarily within the female population (subset 1: 67.3%; subset 2: 80%). The benign grade of meningiomas was reported as the most common (70.4%), of which the meningothelial subtype (48%) was predominant. Meningiomas were mostly observed within the supratentorial region (subset 1: 57.2%; subset 2: 91.7%) with almost equal incidences in subset 1 and a majority on the right side in subset 2. Regarding tumour volume, subset 1 revealed the largest meningiomas within the supratentorial region (90.9 cm3), and subset 2 revealed an average tumour volume of 43.9 cm3. In terms of meningioma vascularity, within the supratentorial region, the external carotid arteries were noted to be a common primary feeder vessel, for the skull base region the primary arterial supply is the internal carotid artery. This study provides insight into the anatomical basis of intracranial meningiomas within a select South African population as it has introduced a novel methodology of meningioma vascularity. This may assist endovascular surgeons in assessing the feeder vessel contributions of meningiomas and understand the prevalence of these anatomical parameters in this population.
Anterior synostotic plagiocephaly: a quantitative analysis of craniofacial features using computed tomography.
(2021) Mohan, Nivana.; Lazarus, Lelika.; Madaree, Anil.; Harrichandparsad, Rohen.
Anterior synostotic plagiocephaly (ASP) is caused by the premature fusion of one coronal suture, which results in severe craniofacial asymmetry that can be challenging to correct. The various methods of the surgical procedures, as well as the distinctive facial characteristics of ASP, have been well documented. However, there is a paucity of literature pertaining to the quantitative analysis of the craniofacial features that are affected in ASP. This study used preoperative computed tomography (CT) scans to document and compare the morphometry of the anterior cranial fossa (ACF), orbit, and ear on the ipsilateral (synostotic) and contralateral (non-synostotic) sides in a select South African population of patients diagnosed with ASP. The dimensions of the ACF, orbit and the position of the ear on the ipsilateral and contralateral sides were measured using a set of anatomical landmarks on two-dimensional (2D) CT scans of 18 consecutive patients diagnosed with non-syndromic ASP. The differences between the ipsilateral and contralateral sides were computed and expressed as a percentage of the contralateral side. The findings of this study revealed that there was side-to-side asymmetry in the ACF, orbit, and ear. All ACF parameters decreased significantly (t-test; p<0.001) on the ipsilateral side when compared to the contralateral side, resulting in the volume of the ACF being the most affected (-27.7%). In terms of the orbit, on the ipsilateral side, the length-infraorbital rim (IOR), height, and surface area parameters increased significantly (t-test; p<0.001), with the height being the most affected (24.6%). The remaining orbital parameters (length-supraorbital rim (SOR), breadth and volume) decreased significantly (t-test; p<0.001), with the length-SOR parameter being the most affected (-10.8%). Furthermore, the ipsilateral SOR was noted to be displaced more cranially by an average of 3.89mm from the contralateral SOR. With regards to the position of the ipsilateral ear, it was found to be displaced anteriorly (9.33mm) and caudally (5.87mm) from the contralateral ear. This study augments the existing literature by providing actual values to corroborate the hallmark characteristics of ASP. These measures may help surgeons plan the technique and extent of surgical correction of the affected craniofacial structures during corrective surgery as it will provide them with an indication of the extent of the deformity on the ipsilateral side as compared to the contralateral side. The results of this study have the potential to propose a grading system in ASP patients according to severity of the condition if the sample size is increased.
Scaphocephaly in a select South African population: a morphometric analysis of the cranial fossae and ventricular access points.
(2021) Bisetty, Vensuya.; Lazarus, Lelika.; Madaree, Anil.; Harrichandparsad, Rohen.
Scaphocephaly is a cranial deformity that results from premature fusion of the sagittal suture and is characterized by an elongated and narrowed skull. Patients with this condition present with varying clinical features including frontal bossing and occipital protrusion. This study comprised two subsets, analysing different aspects related to this cranial deformity. Most morphological and morphometrical studies in patients with scaphocephaly focus on the cranial vault. Literature on the morphometry of the cranial base and its fossae in these patients is sparse. Therefore, the first subset aimed to analyse and compare the morphometry of the cranial fossae in patients with scaphocephaly. Due to varying cranial morphology among patients with these deformities, ventricular access using conventional techniques is often a challenge. Although ventricular access may not be frequently required in paediatric scaphocephalic patients, it is vital that an ideal location of the access points be established for safe ventricular catheterization. Accordingly, the second subset aimed to document the morphometry of Kocher’s and Frazier’s points in scaphocephalic patients using known craniometric and surface anatomical landmarks. Dimensions of the anterior, middle and posterior cranial fossae (ACF, MCF and PCF) were measured using select anatomical landmarks on computed tomography (CT) scans of 24 consecutive patients diagnosed with scaphocephaly between 2014 and 2020, and 14 non-affected/ normal paediatric patients selected as controls. Parameters of Kocher’s and Frazier’s points were measured in relation to known cranial surface anatomical landmarks on scans of the scaphocephalic patients utilized in subset 1. The study found that ACF and PCF are most affected in scaphocephalic patients, with elongation along the anteroposterior (AP) plane (lengths) (ACF, p=0.041 and PCF, p=0.018). Minimal changes were observed in the transverse plane (widths) in scaphocephaly versus non-affected/normal controls. Regarding subset 2, Kocher’s point was located between 91.6mm and 140mm posterior to the nasion, and between 20.5mm and 34.6mm lateral to the midline in patients with scaphocephaly. Frazier’s point was located between 60.9mm and 82.8mm superior to the inion, and 25.9mm and 41.4mm lateral to the midline. Parameters measured in the AP plane were found to be more affected than those measured lateral from the midline. This study contributes to the literature by providing novel morphometric data based on a select South African population. Data obtained could aid craniofacial surgeons in understanding which cranial fossa is most affected in scaphocephaly and to what extent, to decide on the most appropriate method of treatment. Additionally, the study concluded that the traditional landmarks used for ventricular access are relatively unreliable in scaphocephalic patients. This study provides data for neurosurgical consideration regarding ventricular catheterization procedures in patients with scaphocephaly.

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