Morphometric analysis of sacral corridor in the upper three sacral segments to prevent neurovascular injury

Morphometric analysis of sacral corridor in the upper three sacral segments to prevent neurovascular injury

Although studies of the sacral corridor dimension have been reported in the European population, little attentionhas been paid to this issue in the Asian population. The purpose of the study is to estimate the safe dimension of the corridorto avoid neurovascular damage during the fixation of the sacral fracture. The study aimed to examine the cephalocaudal(vertical) and the anteroposterior diameter of the bony passage in the upper three sacral segments. The study furtherexamines the effect of age and sex on corridor dimensions at different sacral levels. Three-dimensionally reconstructed sacrafrom computed tomography of normal subjects were included in the study. Cephalocaudal and anteroposterior diameterswere measured in coronal and axial sections using Geomagic Freeform Plus software. Anteroposterior diameter of thesacral corridor at the first, second, and third sacral segments are significantly higher in males (P=0.013, 0.0011, and <0.0001,respectively). The length of the sacrum also revealed sexual dimorphism (P<0.00016). The anteroposterior diameter ofthe second sacral segment (ap-S2c) correlated moderately with the first sacral anteroposterior diameter (ap-S1c) (R=0.519,P<0.001). The ap-S2c exhibited a moderate correlation to the third sacral segment (ap-S3c) (R=0.677, P<0.001). The sacralcorridor at the level of S1 has the largest cephalocaudal (18.25 mm) and anteroposterior diameter (17.11 mm). Placement of thescrew in the first sacral corridor may avoid damage to the neurovascular bundle during the fixation of the sacral fracture.