xRead - Nasal Obstruction (September 2024) Full Articles

20426984, 2021, 3, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/alr.22741 by Stanford University, Wiley Online Library on [01/07/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License

230

International consensus statement on rhinosinusitis

Arteries suspended below the skull base are more susceptible to injury during sinus surgery. Damage to the artery can result in hemorrhage, CSF leak, or orbital hematoma.

Inadvertent injury to the skull base is more likely in the presence of an asymmetric skull base or areas of bony dehiscence. Similarly, injury to the orbit, carotid artery, and optic nerve is increased with areas of bony dehiscence/abnormalities.

TABLE I-7 Anatomic relationships to consider during sinus surgery to prevent complications Anatomic Findings Description Importance Maxillary-to-Ethmoid Ratio Ratio of the maxillary sinus height to the posterior ethmoid height (just posterior to the basal lamella) in the coronal plane Inadvertent injury to the skull base is more likely to occur if the maxillary to ethmoid vertical height ratio is greater than 1:1. Height of the Lateral Lamella (Keros Classification) The length of the lateral cribriform lamella relative to the fovea ethmoidalis ∙ Keros I: 1-3 mm ∙ Keros II: 3-7 mm ∙ Keros III: 8-16 mm Risk for intracranial injury is positively correlated with higher Keros classification. It is critical to note for any asymmetry of the skull base or areas of bony dehiscence. Sphenoid Sinus Pneumatization/Onodi Cell

The sphenoid sinus is helpful in identifying the anterior skull base. There is an increased risk of optic nerve injury if an Onodi cell is present or there is bony dehiscent present.

Risk of carotid artery injury increases if there is an insertion of an intersinus septation or overlying bony dehiscence.

Ethmoidal Arteries Determine if the location of the anterior and posterior ethmoid arteries are traversing through the skull base or suspended below ∙ Intersinus septation inserting onto carotid canal ∙ Dehiscence over the carotid canal or optic nerve Skull Base Asymmetry/Bony Dehiscence Table adapted from May et al. 104 and Asaka et al. 100 Classify the pneumatization pattern of the sphenoid sinus (conchal, presellar, sellar).Identify the presence or absence of: ∙ Onodi cell

Evaluate for any areas of asymmetry (height and thickness) within the skull base. Examine the continuity of the bone overlying the lamina papyracea, carotid canal, and optic nerve