Prevalence of the Caroticoclinoid Foramen in Brazilian Dry Skulls

Introduction: The Caroticoclinoid Foramen (CCF) is a variation found in the sphenoid. It gives passage to the internal carotid artery and it is a surgically significant structure when dealing with the cavernous sinus. There is debate, however, regarding its prevalence, especially in populations from South America. Aim: The aim of this study was to assess the prevalence and size of the CCF in a Brazilian sample. Materials and Methods: This was a cross-sectional study carried out for a period of 10 months during March 2019 and January 2020. The present study was conducted in 365 dry human skulls from two Universities in the Southeast region of Brazil. The caroticolinoid foramen was observed and if present, measured. Results: Of the 365 skulls examined, the foramen was present in 101 (prevalence of 27.6%). The foramen was bilateral in 88 cases, while 13 skulls presented this variation unilaterally (7 on the right and 6 on the left side), thus reaching a total of 189 foramina. The mean anteroposterior diameter was 4.87±0.69 mm (right side) and 4.86±0.79 mm (left side), and the Transverse Diameter (TD) was 4.85±0.75 mm (right side) and 4.74±0.73 mm (left side). Sixty-nine skulls had data regarding sex and age. The age ranged from 1 month old to 104-year-old (mean of 37.79±21.85-year-old). The male to female ratio was 2:1, being the only relation with statistical significance (p<0.05). Conclusion: The CCF can be a common variation depending on the population analysed. Thus, the surgeon should always be concerned of its presence, as its misidentification may lead to a negative surgical outcome.

Morphological Variation of Anterior Clinoid Process in Dry Human Skulls

Introduction: The anatomical relationship of the Anterior Clinoid Process (ACP) with its neighboring structures in the base of the skull is complex with different variations. Thus, study of its morphology is essential in defining and directing surgery. Objective: This study aims to investigate the anatomy of the anterior clinoid process and prevalence of Caroticoclinoid foramen (CCF) to highlight its variations. Methodology: The measurements were performed in 31 dry human skulls to define the structure of ACP, the presence of CCF and other relevant landmarks using digital Vernier Calipers. Results: The mean length, basal width and thickness of the right ACP was 9.88+/- 1.36 mm, 8.72+/-1.50 mm, and 5.21+/-1.83 mm respectively and that of the left was 10.30+/-1.47, 8.73+/-1.71, and 5.33+/-1.60 mm respectively. Paired t-test was used to compare the mean of these sides. Type III was the most common form of ACP for both the sides. Out of 31 skulls, CCF was observed in 12 (38.7%) skulls with 7 (22.6%) in right and 5 (16.13%) in left side. Distances between neighboring ACP’s, between Posterior Clinoid process (PCP), between ACP to Crista Galli (CG) and ACP to PCP were 24.41+/-2.32, 20.01+/-3.23, 31.6+/-2.20, and 8.30+/-3.10 mm respectively. Conclusion: This article highlights the detailed morphology of ACP. There is variation in relation to its dimensions across other studies. This study also explores the prevalence of CCF and parasellar landmarks in relation to ACP giving an idea of the exposure achievable during surgical approach of the region.

The caroticoclinoid foramen in fetal and infantile orbitosphenoid, presphenoid, and sphenoid bones: developmental and neurosurgical considerations

OBJECTIVEThe presence of a caroticoclinoid foramen may increase the likelihood of adverse neurosurgical events. Despite the clinical importance of the caroticoclinoid foramen, its study has been mostly limited to adult populations. Therefore, the object of this study was to describe the prevalence, morphology, and development of the caroticoclinoid foramen among varied sexes and races in early life.METHODSThe study analyzed caroticoclinoid foramina in dry orbitosphenoid, presphenoid, and sphenoid bones from a population of 101 fetal and infantile crania of varied sex and race.RESULTSA caroticoclinoid foramen, whether complete, near complete, or partial, was found in 36 of 199 sides (18.1%). Of the 98 crania with bilaterally intact sides, 21 (21.4%) had the presence of at least one caroticoclinoid foramen. Caroticoclinoid foramina were found unilaterally and bilaterally, in both female and male crania (9/41, 22.0%; 12/57, 21.1%, respectively) and, likewise, in crania of both black and white races (9/54, 16.7%; 12/44, 27.3%, respectively). Caroticoclinoid foramina were formed from cornuate bony projections from the anterior clinoid process, middle clinoid process, or both anterior and middle clinoid processes. Caroticoclinoid foramina were also found in isolated orbitosphenoid bones from individuals as young as 4 months’ fetal age.CONCLUSIONSThe caroticoclinoid foramen occurs in approximately one of every 5 sides and in one in every 5 individuals of perinatal age and should, therefore, be considered a common finding in both fetuses and infants. It is common in both females and males as well as in both black and white races, alike. Furthermore, the caroticoclinoid foramen can be found in individuals as young as 4 months of fetal age. Failure to anticipate the presence of a caroticoclinoid foramen will place important neurovascular structures, including the internal carotid artery, at risk of injury. Neurosurgeons should, therefore, anticipate the caroticoclinoid foramen even in their youngest patients.

Morphology of the anterior clinoid process in a select Kenyan population

Knowledge of the morphological variations of the anterior clinoid process is pertinent during anterior clinoidectomy to prevent injury to the adjacent neurovascular structures as well as in the interpretation of skull base radiographs. Fifty-one open crania (102 anterior clinoid processes) were obtained from the Departments of Human Anatomy in three Kenyan Universities. Caroticoclinoid foramen was present in nine (17.6%) out of the 51 skulls studied. Of the 9 skulls, 2 had bilateral complete foramina while the remaining 7 had unilateral foramina, all on the left side. The mean length of the anterior clinoid process ranged between 5.0 and 18.8mm with a mean of 10.92±2.79 mm. The mean width was found to be 10.43±2.67 mm (range: 5.3-18.0mm) while the average thickness was 5.43±2.02mm (range: 1.3-11.9mm). There were no statistically significant side differences in the dimensions of the anterior clinoid process. Type IIIb anterior clinoid process was the commonest (47.1%) while type IIIa was the least common (7.8%). Compared to other populations, the anterior clinoid process in our setting shows some differences involving its type and the caroticoclinoid foramen. These features should be taken into account when interpreting skull base radiographs and planning for anterior clinoidectomies.Keywords: Clinoid Process, Kenya, Morphology

Surgically Relevant Bony Anatomical Variations in Paraclinoid Aneurysms-Three-Dimensional Multi-Detector Row Computed Tomography-Based Study

ABSTRACT Objective: To evaluate the proportion of surgically relevant anatomical variations such as caroticoclinoid foramen, interclinoid osseous bridge, and anterior clinoid pneumatization in patients with paraclinoid aneurysms based on computed tomography (CT) cerebral angiography studies. Materials and Methods: Fifty-four CT cerebral angiography studies showing paraclinoid aneurysms involving the cavernous, clinoid, and supraclinoid internal carotid artery (ICA) were retrospectively evaluated. Source images were processed for three-dimensional reconstructions to evaluate the presence and type of caroticoclinoid foramen, interclinoid osseous bridge, and multiplanar reconstructions with bone algorithm to study the type of pneumatization. Results: The study included 30 female and 24 male patients with mean age of 45.61 (10.47) years. Among the 108 sides studied in 54 patients, caroticoclinoid foramen was seen in 24 cases (22.22%), interclinoid osseous bridge was seen unilaterally in 1 case (0.9%), and pneumatization of anterior clinoid process occurred in 12 cases (11.11%). Incomplete caroticoclinoid foramen (11 cases) and Type I pneumatization (7 cases) were seen to be predominant subtypes. There was no statistically significant gender difference in the occurrence of caroticoclinoid foramen and anterior clinoid pneumatization. Seventy-four aneurysms were detected in 54 patients. Based on their location, 46 aneurysms involved supraclinoid ICA, 18 aneurysms in the clinoid segment, and 10 aneurysms in the cavernous segment. Caroticoclinoid foramen was most prevalent in clinoid aneurysms with 12 cases occurring in the clinoid segment. Conclusion: Notable proportions of caroticoclinoid foramen and pneumatization occur in cases of paraclinoid aneurysm. Radiological reports should emphasize on these surgically relevant bony anatomical variations.