Morphometry of <i>Occipital condyles</i>: Implications for transcondylar approach to craniovertebral junction lesions

Abstract

Partial occipital condylectomies are commonly done in trans-condylar approach to craniovertebral junction lesions. Following such procedures, post-operative atlanto-occipital joint instability and hypoglossal nerve palsies have been reported and has been attributed to population-specific variations in the occipital condyle (OC) dimensions. Determination of these dimensions may aid in minimizing these complications. One hundred and four (104) OC from 52 skulls (27 males, 25 females) were obtained from the osteology department, National Museums of Kenya. Occipital condyle length (OCL), width (OCW), height (OCH), anterior (AID) and posterior (PID) intercondylar distances and the distance from posterior tip of OC to hypoglossal canal (HC) were obtained using a pair of digital Vernier calipers. The data obtained were entered into SPSS for analysis. The mean OCL, OCW and OCH were 20.59±2.05 mm, 12.23±1.28 mm and 8.65±1.08 mm respectively while AID and PID were 19.66±2.70 mm and 38.52±3.09 mm respectively. Moderate OC type was the most predominant (60.6%). Males and females had predominantly moderate and short OC type respectively (p=0.001). The HC was located 9.62±1.62 mm from the posterior tip of the OC. Males had significantly larger OCL (p<0.001), OCH (p=0.001), PID (p=0.002) and posterior tip of OC to HC distance (p=0.008). Our study population generally has smaller OC dimensions compared to other populations. Females had significantly smaller OCL, OCH, OC-HC distance and PID. Clinicians should therefore take this information into consideration during preoperative planning in craniovertebral junction surgeries among Kenyans and  particularly in females.

Key Words: Occipital condyles, Morphometry, Transcondylar approach