Anatomic study of the occipital condyle and its surgical implications in transcondylar approach

Abstract

Background:Craniovertebral surgeries require the anatomical knowledge of craniovertebral junction. The human occipital condyle (OC) is unique bony structure connecting the cranium and the vertebral column. A lateral approach like transcondylar approach (TA) requires understanding of the relationships between the OC, jugular tubercle, and hypoglossal canal. Hence, the aim of the present study was to analyze the morphological variations in OCs of dry adult human skull.Materials and Methods:The study was carried out on 142 OC of 71 adult human dry skulls (55 males and 16 females). Morphometric parameters such as length, width, thickness, intercondylar distances, and the distances from the OC to the foramen magnum, hypoglossal canal and jugular foramen were measured. In addition, the different locations of the hypoglossal canal orifices in relation to the OC and different shapes of the OC were also noted.Results:The average length, width and height of the OC were found to be 2.2, 1.1 and 0.9 cm. The anterior and posterior intercondylar distances were 2.1 and 3.9 cm, respectively. Maximum and minimum bicondylar distances were 4.5 and 2.6 cm, respectively. The intra-cranial orifice of the hypoglossal canal was found to be present in middle 1/3rd in all skulls (100%), and extra-cranial orifice of the hypoglossal canal was found to be in anterior 1/3rd (98%) in relation to OC. The oval shaped OC (22.5%) was the most predominant type of OC observed in these skulls.Conclusion:Occipital condyle is likely to have variations with respect to shape, length, width and its orientation. Therefore, knowledge of the variations in OC along with careful radiological analysis may help in safe TAs during skull base surgery.

Foramen magnum, occipital condyles and hypoglossal canals morphometry: anatomical study with clinical implications

“…To our view, the sample size is the major factor that influences Parvindokht et al [28] findings. Side symmetry of the OCs thickness and higher values were detected in our sample in males (right, 10.13 ± 1.53 mm and left side, 10.17 ± 1.38 mm) and females (right, 10.09 ± 1.66 mm and left side, 9.88 ± ± 1.51 mm) in contrast to findings of Kalthur et al [14] who found side asymmetry among genders calculating OCs thickness in males (right, 10.4 ± 2.0 mm and left side, 9.9 ± 1.4 mm) and females (right, 9.5 ± 2.0 mm and left side, 8.6 ± 1.4 mm).…”

Morphological Analysis of Occipital Condyles and Foramen Magnum as a Guide for Lateral Surgical Approaches

“…Although some studies suggested these did not have a correlation with the sagittal and the transverse diameter of the FM [43], other studies reported a sexual dimorphism for FM dimensions with all parameters being significantly higher in males [44]. Kamath et al [45] found sex predictability (higher values in males) for FM area (70.3%), followed by sagittal diameter (69.6%), and least for transverse diameter (66.4%), similar to the study of Uthman et al [46] for FM area and Raghavendra Babu et al [47] with higher predictability for FM area and sagittal diameter compared to transverse diameter [9]. Rai et al [48] found OC and FM dimensions higher in males compared to females No stastistically significant difference was found in adults for different age groups for the OC [49] and FM [50].…”

“…and intrinsic lesions [9]. Occipitocervical synostosis is one of the most frequent osseous anomalies of the CVJ and may compress the brainstem, vertebral artery and cranial nerves [10].…”

Morphological Analysis on the Occipital Condyles and Review of the Literature

“…There are several anatomical studies in the literature reporting the importance of morphometric variations of the occipital condyles (Kumar & Nagar, 2014, Kavitha et al, Natsis et al, Bayat et al, Das et al, Naderi et al, Ozer et al, Kizilkanat et al, Muthukumar et al, Avci et al, 2011, Bozbug˘a et al, 1999, Kalthur et al, 2014, El-Gaidi et al, 2014, Gapert et al, 2009) and radiological studies have also been conducted (Avci et al, Le et al, 2011, Hong et al, 2011, Noble & Smoker, 1996. Knowledge of the topography of different neurovascular structures located around the region of the occipital condyles is highly important with regard to conducting neurosurgical procedures (transcondylar approach) and obtaining good results.…”