Exploring the Influence of Olfactory Epithelium Histology on Age-Related Olfactory Recovery after Endoscopic Endonasal Anterior Skull Base Surgery

Introduction: Utilizing the endoscopic trans-sphenoidal approach (TSA) for anterior skull base procedures has demonstrated an impact on postoperative olfactory function. Age is acknowledged as a notable factor influencing olfactory recuperation following damage to the olfactory organ. This study aims to explore the connection between age and postoperative olfactory recovery following endoscopic TSA, as well as to investigate how histological features of the olfactory epithelium interact with age-related olfactory recovery after endoscopic TSA.

Methods: We conducted a retrospective analysis on patients who underwent endoscopic TSA combined with unilateral posterior ethmoidectomy, large-sized rescue flap, and olfactory strip elevation. Excluded from the study were patients with a history of revision surgery due to CSF leakage, intracranial hemorrhage, or tumor recurrence. We assessed pre- and postoperative olfactory function using the Cross-Cultural Smell Identification Test (CCSIT) and olfaction questionnaires and examined the relationship with demographic and tumor characteristics. In an additional patient cohort, we sampled the lower 1/3 of the superior turbinates during endoscopic TSA and subjected them to immunofluorescence staining for histological analysis of olfactory epithelium to determine their impact on age-related olfactory outcomes after endoscopic TSA.

Results: We analyzed a group of 46 patients, with a mean age of 54.5 (±14.7) and a male-to-female ratio of 26:20. Pituitary adenoma was the most frequently diagnosed tumor type, affecting 73.9% of the patients. Age exhibited a negative correlation with olfactory function at both 3-month (rho = −0.367, p = 0.022) and 6-month (rho = −0.389, p =0.028) postoperative time points. Additionally, we assessed 21 patients histologically regarding the olfactory epithelium, and the number of OMP/PGP double-positive cells (mature olfactory sensory neurons), p63 positive cells (horizontal basal cells), and Mash 1 positive cells (globose basal cells) showed a negative association with age (rho = −0.56, p = 0.004; rho = − 0.616, p =0.001; rho = −0.676, p < 0.001, respectively). Among these patients, 9 underwent postoperative olfactory testing. The number of OMP/PGP double-positive cells, as well as Mash 1 positive cells, showed a trend towards association with olfactory recovery, but this association did not reach statistical significance (rho = −0.283, p = 0.460; rho = −0.305, p = 0.425, respectively).

Conclusion: There exists a negative correlation between age and olfactory recovery following endoscopic endonasal skull base surgery. It appears that histological characteristics with a higher number of mature olfactory sensory neurons and basal cells are linked to more favorable olfactory outcomes in younger patients.

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Artikel online veröffentlicht:
05. Februar 2024