The risk of olfactory disturbance from conchal plate injury during ethmoidectomy

Background: Even though the olfactory function usually is improved or unchanged after ethmoidectomy some patients complain of olfactory disturbance, which may be caused by direct injury to the olfactory nerves. However, the detailed anatomic pathway of the olfactory nerves that leave the olfactory mucosa and after going through the cribriform plate insert into the olfactory bulb is uncertain. In the studies of lateral nasal wall, we referred to the thin bone that connects the middle, superior, and supreme turbinates to the skull base as the "conchal plate." We undertook this study to determine the anatomic relation between the conchal plate and the olfactory nerve. Methods: Ten midsagittal sections from adult cadaver head specimens were used for gross anatomy and the midportion of the conchal plate vas taken and fixed in 10% formalin. The microscopic structures of the conchal plate were observed after hematoxylin and eosin staining. Results: The olfactory nerves originated from the olfactory mucosa lining the middle and superior turbinates and ran upward within the bone of the conchal plate. These results suggest that the olfactory nerve may be injured inadvertently in the conchal plate during ethmoidectomy and that this injury is likely to be one of the possible causes of olfactory disturbance. Conclusion: We propose a possibility that injury to the conchal plate call affect olfactory function. Therefore, care should be taken to a void damage to the conchal plate during ethmoidectomy.