Tsiouris Christos, Triantafyllou George, Karangeli Nektaria, Botis George G, Papadopoulos-Manolarakis Panagiotis, Kalamatianos Theodosis, Tsakotos George, Piagkou Maria
Department of Anatomy, School of Medicine, Faculty of Health Sciences, National and Kapodistrian University of Athens, 11527 Athens, Greece.
Biomedical Engineering Laboratory, School of Electrical and Computer Engineering, National Technical University of Athens, 15773 Zografou, Greece.
Diagnostics (Basel). 2025 May 28;15(11):1359. doi: 10.3390/diagnostics15111359.
The morphology of the occipital condyles (OCs) and foramen magnum (FM) is critical for neurosurgical planning and forensic identification. However, pooled reference values and the impact of study-level moderators on morphometric estimates remain underexplored. A systematic review and meta-analysis were conducted to estimate pooled morphometric values of the OCs and FM. Databases were searched for studies reporting relevant data in adult human subjects. A random-effects model was used to calculate pooled means and mean differences (MDs) by sex and side (left vs. right). Risk of bias and study quality were assessed. Subgroup analyses were conducted based on study design (osteological vs. imaging) and geographical region. Meta-CART (classification and regression trees) was used to explore moderator interactions and identify data-driven subgroups contributing to heterogeneity. A total of 61 studies comprising 8010 adult skulls met the inclusion criteria. Substantial heterogeneity was observed across studies; most were assessed as having low-to-moderate methodological quality and a high risk of bias. The pooled mean values were as follows: OC length (OCL): 21.51 mm, OC width (OCW): 11.23 mm, OC thickness (OCT): 9.11 mm, FM length (FML): 35.02 mm, and FM width (FMW): 28.94 mm. Morphometric values reported in imaging-based studies were consistently lower than those from osteological studies. Evident sexual dimorphism was identified, with males exhibiting larger dimensions than females. The most pronounced sex-based mean differences (MDs)-approximately 2 mm-were found in OCL, FML, and FMW. In contrast, differences in OCT and OCW were under 1 mm. No significant side-related asymmetries were observed overall. Subgroup analysis revealed that sex-related MDs were more prominent in imaging studies, particularly for the right OCL and OCW. Meta-CART analysis identified study design as the strongest moderator for OCL, OCW, and FML. Sexual dimorphism was more pronounced in imaging studies but statistically insignificant in osteological samples. Furthermore, sex emerged as a stronger predictor for OCL than OCW, while geographical region had a greater impact on OCW. For OCT, geographical region was the main influencing factor, whereas sex was the primary moderator for FMW. OC and FM morphometry exhibit substantial heterogeneity across studies. Imaging-based methods more effectively detect sex-related differences, underscoring their utility in forensic identification and neurosurgical planning. These findings emphasize the need for more standardized, high-quality morphometric research to support population-specific anatomical reference data.
枕髁（OCs）和枕骨大孔（FM）的形态对于神经外科手术规划和法医鉴定至关重要。然而，汇总参考值以及研究水平的调节因素对形态测量估计值的影响仍未得到充分探索。进行了一项系统综述和荟萃分析，以估计OCs和FM的汇总形态测量值。检索数据库以查找报告成年人类受试者相关数据的研究。采用随机效应模型按性别和侧别（左侧与右侧）计算汇总均值和均值差异（MDs）。评估偏倚风险和研究质量。基于研究设计（骨学研究与影像学研究）和地理区域进行亚组分析。使用Meta-CART（分类与回归树）来探索调节因素的相互作用，并识别导致异质性的数据驱动亚组。共有61项研究（包括8010个成年颅骨）符合纳入标准。各研究间观察到显著的异质性；大多数研究被评估为方法学质量低至中等，且偏倚风险高。汇总均值如下：枕髁长度（OCL）：21.51毫米，枕髁宽度（OCW）：11.23毫米，枕髁厚度（OCT）：9.11毫米，枕骨大孔长度（FML）：35.02毫米，以及枕骨大孔宽度（FMW）：28.94毫米。基于影像学研究报告的形态测量值始终低于骨学研究中的值。确定了明显的性别二态性，男性的尺寸大于女性。在OCL、FML和FMW中发现基于性别的最显著均值差异（MDs）约为2毫米。相比之下，OCT和OCW的差异小于1毫米。总体未观察到显著的侧别相关不对称性。亚组分析显示，与性别相关的MDs在影像学研究中更为突出，特别是右侧的OCL和OCW。Meta-CART分析确定研究设计是OCL、OCW和FML的最强调节因素。性别二态性在影像学研究中更明显，但在骨学样本中无统计学意义。此外，性别对OCL的预测作用比OCW更强，而地理区域对OCW的影响更大。对于OCT，地理区域是主要影响因素，而性别是FMW的主要调节因素。OC和FM的形态测量在各研究间表现出显著的异质性。基于影像学的方法能更有效地检测与性别相关的差异，突出了它们在法医鉴定和神经外科手术规划中的实用性。这些发现强调需要更标准化、高质量的形态测量研究，以支持针对特定人群的解剖学参考数据。
