Piriform Height and the Clival Length as Predictors of the Size and Surgical Freedom of the Transclival Corridor

The transclival corridor is a commonly used endoscopic endonasal approach to treat pathologies of the central and posterior skull base. We present a predictive model that uses the piriform height and clival length to predict the size of and the surgical freedom of this corridor. A total of 103 computed tomography scans of the head were selected. Exclusion criteria included patients <18 years of age, radiographic evidence of trauma, neoplasm, infection, or previous surgery. The images were analyzed using OsiriX MD (Bernex, Switzerland). We measured the clival length, clival surface area, and sagittal and coronal angles of the transclival corridor. We used univariate linear regression to create a prediction model, and cross folding to test the validity of the model. We included 103 patients with an average age of 44.9 years and 47% males. The mean clival length was 44.8 mm (SD ± 3.7), surface area 8.6 cm² (SD ± 1.5), and coronal FOM 32.4 degrees (SD ± 4.1). The sagittal FOM and the piriform heights were 61.1 degrees (SD ± 4.3) and 32.1 mm (SD ± 4.4), respectively ([Fig. 1]). Using the clival length and piriform height, our model showed good fitness and validity in predicting the size and freedom of movement of the transclival corridor. It can be used clinically to help guide neurosurgeons to determine the optimal surgical corridor using patients' anatomy.

Fig. 1

Publication History

Article published online:
12 February 2021