Looking for landmarks in medial orbital trauma surgery.

Knowledge of the precise location of anatomical landmarks such as the anterior (AEC) and posterior ethmoid (PEC) canals facilitates medial orbital wall surgery and is of major importance for the protection of the orbital nerve. The aim of this study was to identify these anatomical structures in 100 consecutive CT scans and measure the distance between them. The authors investigated whether a predictable symmetry existed between the left and right side. The AEC was not identified unilaterally in one patient, the PEC was not identified unilaterally in six patients and not bilaterally in one patient. An additional PEC was found unilaterally in 12 and bilaterally in five patients. If an anatomical structure was found bilaterally, the authors obtained a strong Pearson's correlation between the sides (r=0.798–0.903, p<0.001). An anatomical variation was found in nearly every fourth patient. The authors think that these data call into question the use of the PEC and AEC as reliable surgical landmarks in medial orbital surgery.