Height and Shape of Skull Base as Risk Factors for Skull Base Penetration during ESS

ABSTRACT

BACKGROUND AND OBJECTIVES: CT/MRI has identified several risk factors for life threatening complications of skull base penetration during endoscopic sinus surgery (ESS). We compared these risk factors in groups of patients with and without penetration. MATERIALS AND METHODS: Retrospective review of direct coronal paranasal sinus computed tomography (CT) scans was done. Using preoperative CT scans of 100 patients without penetration, and 7 with penetration, we classified height into 4 groups and contour into 2 groups. The frequencies of shape and height differences of the right and left skull base were calculated in each group. RESULTS: 6 of the 7 patients who had skull base penetration, ESS was performed by a resident or junior staff member having less than 3 years experience with this technique. Shape asymmetry was significantly higher in with penetration (4 out of 7 patients (57%)) and much less in without penetration (18 out of 100 patients, 18%, p=0.032). The frequencies of low skull base and height difference were seen in 15% and 28%, respectively. CONCLUSION: The most important risk factor for inadvertent skull base penetration during ESS is the surgeon's experience and asymmetric shape of the right and left skull base.